https://airwiki.elet.polimi.it/api.php?action=feedcontributions&user=StefanoCapelli&feedformat=atomAIRWiki - User contributions [en]2024-03-29T11:52:26ZUser contributionsMediaWiki 1.25.6https://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12932Talk:Servomechanisms (aka "Servos")2011-01-27T13:19:07Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li><br />
<li><br />
found a convenient place, like a table, to support in keeping the servo still during the test, while allowing enough vertical room below of it (for the objects that provide the force)</li><br />
</ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second test run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up our servo for a new test run: this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br><br />
Final temperature: 48 °C<br><br />
Motion degradation: significantly slower, but still effective to rotate and lift the weight<br><br />
<br />
On the temperature chart (below, yellow line) we see that the servo heating looks normal only during the first five minutes, and since the final motion degradation in not acceptable, we decide to reduce the applied torque.<br />
<br />
At the same time we redefine our testing procedure:<br />
<br />
<ul><li>we want to use something stable for keeping the servo in place during our test, like a bench vice - so we mount our servo on its support (the one in use on E-2?), which we have previously attached on a Item 5 series profile.<br />
This way we can use the bench vice of AIRLab to make the Item profile and everything stand still (instead of holding it manually on the table's edge) so we can focus on the testing activity</li><br />
<li>we use a lower torque by reducing the arm's length, and we adopt a new horn (the one in the image) which does not interfere with the cord that holds the weight, during shaft operations<br>[[Image:Servo_arm_148SH.jpg]]<br>&nbsp;</li><br />
<li>we operate the servo during the first test like in the previous run: making the arm stand still in the horizontal position, to achieve the maximum torque, then at the end of the test we go down and up again</li><br />
<li>we do the second test applying continuously this pattern of movements:<br />
<ul><br />
<li>5 up and down cycles, normal speed: period of approx. 3 seconds (2 second to go up, 1 second down)</li><br />
<li>1 up and down cycle, quick</li><br />
<li>10 seconds standing in a low stress position</li></ul><br />
</li></ul><br />
<br />
We've had these same results for both the test runs:<br />
<br />
Torque applied: '''46.73 kgf*mm'''<br><br />
Final temperature: 41 °C<br><br />
Motion degradation: reasonably slower<br><br />
<br />
We can accept this new estimate, given the premises above regarding the continuous torque, and it's interesting to point out that this torque equals the 49% of the stall torque declared on the box of the servo.<br />
<br />
[[Image:Servo_test_runs.png]]</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12931Talk:Servomechanisms (aka "Servos")2011-01-27T13:11:42Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second test run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up our servo for a new test run: this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br><br />
Final temperature: 48 °C<br><br />
Motion degradation: significantly slower, but still effective to rotate and lift the weight<br><br />
<br />
On the temperature chart (below, yellow line) we see that the servo heating looks normal only during the first five minutes, and since the final motion degradation in not acceptable, we decide to reduce the applied torque.<br />
<br />
At the same time we redefine our testing procedure:<br />
<br />
<ul><li>we want to use something stable for keeping the servo in place during our test, like a bench vice - so we mount our servo on its support (the one in use on E-2?), which we have previously attached on a Item 5 series profile.<br />
This way we can use the bench vice of AIRLab to make the Item profile and everything stand still (instead of holding it manually on the table's edge) so we can focus on the testing activity</li><br />
<li>we use a lower torque by reducing the arm's length, and we adopt a new horn (the one in the image) which does not interfere with the cord that holds the weight, during shaft operations<br>[[Image:Servo_arm_148SH.jpg]]<br>&nbsp;</li><br />
<li>we operate the servo during the first test like in the previous run: making the arm stand still in the horizontal position, to achieve the maximum torque, then at the end of the test we go down and up again</li><br />
<li>we do the second test applying continuously this pattern of movements:<br />
<ul><br />
<li>5 up and down cycles, normal speed: period of approx. 3 seconds (2 second to go up, 1 second down)</li><br />
<li>1 up and down cycle, quick</li><br />
<li>10 seconds standing in a low stress position</li></ul><br />
</li></ul><br />
<br />
We've had these same results for both the test runs:<br />
<br />
Torque applied: '''46.73 kgf*mm'''<br><br />
Final temperature: 41 °C<br><br />
Motion degradation: reasonably slower<br><br />
<br />
We can accept this new estimate, given the premises above regarding the continuous torque, and it's interesting to point out that this torque equals the 49% of the stall torque declared on the box of the servo.<br />
<br />
[[Image:Servo_test_runs.png]]</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=File:Servo_test_runs.png&diff=12930File:Servo test runs.png2011-01-27T13:02:55Z<p>StefanoCapelli: </p>
<hr />
<div></div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12929Talk:Servomechanisms (aka "Servos")2011-01-26T19:32:39Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second test run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up our servo for a new test run: this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br><br />
Final temperature: 48 °C<br><br />
Motion degradation: significantly slower, but still effective to rotate and lift the weight<br><br />
<br />
On the temperature chart we see that the servo heating looks normal only during the first five minutes, and since the final motion degradation in not acceptable, we decide to reduce the applied torque.<br />
<br />
At the same time we redefine our testing procedure:<br />
<br />
<ul><li>we want to use something stable for keeping the servo in place during our test, like a bench vice - so we mount our servo on its support, which we have previously attached on a Item basic profile.<br />
This way we can use the bench vice of AIRLab to make the Item profile and everything stand still (instead of holding it manually on the table's edge) so we can focus on the testing activity</li><br />
<li>we use a lower force, by adopting a shorter arm, the one in the image, which has the advantage of not interfering with the cord during operations<br>[[Image:Servo_arm_148SH.jpg]]<br></li><br />
<li>we operate the servo during the first test like in the previous run: making the arm stand still in the horizontal position, to achieve the maximum torque, then at the end of the test we go down and up again</li><br />
<li>we do the second test applying continuously this pattern of movements:<br />
<ul><br />
<li>5 up and down cycles, normal speed: period of approx. 3 seconds (2 second to go up, 1 second down)</li><br />
<li>1 up and down cycle, quick</li><br />
<li>10 seconds standing in a low stress position</li></ul><br />
</li></ul><br />
<br />
We've had these same results for both the test runs:<br />
<br />
Torque applied: '''46.73 kgf*mm'''<br><br />
Final temperature: 41 °C<br><br />
Motion degradation: reasonably slower<br><br />
<br />
We can accept this new estimate, given the premises above regarding the continuous torque, and it's interesting to point out that this torque equals the 49% of the stall torque declared on the box of the servo.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12928Talk:Servomechanisms (aka "Servos")2011-01-26T19:30:13Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second test run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up our servo for a new test run: this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br><br />
Final temperature: 48 °C<br><br />
Motion degradation: significantly slower, but still effective to rotate and lift the weight<br><br />
<br />
On the temperature chart we see that the servo heating looks normal only during the first five minutes, and since the final motion degradation in not acceptable, we decide to reduce the applied torque.<br />
<br />
At the same time we redefine our testing procedure:<br />
<br />
<ul><li>we want to use something stable for keeping the servo in place during our test, like a bench vice - so we mount our servo on its support, which we have previously attached on a Item basic profile.<br />
This way we can use the bench vice of AIRLab to make the Item profile and everything stand still (instead of holding it manually on the table's edge) so we can focus on the testing activity</li><br />
<li>we use a lower force, by adopting a shorter arm, the one in the image, which has the advantage of not interfering with the cord during operations<br>[[Image:Servo_arm_148SH.jpg]]<br></li><br />
<li>we operate the servo during the first test like in the previous run: making the arm stand still in the horizontal position, to achieve the maximum torque, then at the end of the test we go down and up again</li><br />
<li>we do the second test applying continuously this pattern of movements:<br />
<ul><br />
<li>5 up and down cycles, normal speed: period of approx. 3 seconds (2 second to go up, 1 second down)</li><br />
<li>1 up and down cycle, quick</li><br />
<li>10 seconds standing in a low stress position</li></ul><br />
</li></ul><br />
<br />
We've had these same results for both the test runs:<br />
<br />
Torque applied: 46.73 kgf*mm<br><br />
Final temperature: 41 °C<br><br />
Motion degradation: reasonably slower<br><br />
<br />
We can accept this new estimate, given the premises above regarding the continuous torque, and it's interesting to point out that this torque equals the 49% of the stall torque declared on the box of the servo.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12927Talk:Servomechanisms (aka "Servos")2011-01-26T19:26:00Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second test run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up our servo for a new test run: this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br />
Final temperature: 48 °C<br />
Motion degradation: significantly slower, but still effective to rotate and lift the weight<br />
<br />
On the temperature chart we see that the servo heating looks normal only during the first five minutes, and since the final motion degradation in not acceptable, we decide to reduce the applied torque.<br />
<br />
At the same time we redefine our testing procedure:<br />
<br />
<ul><li>we want to use something stable for keeping the servo in place during our test, like a bench vice - so we mount our servo on its support, which we have previously attached on a Item basic profile.<br />
This way we can use the bench vice of AIRLab to make the Item profile and everything stand still (instead of holding it manually on the table's edge) so we can focus on the testing activity</li><br />
<li>we use a lower force, by adopting a shorter arm, the one in the image, which has the advantage of not interfering with the cord during operations<br>[[Image:Servo_arm_148SH.jpg]]<br></li><br />
<li>we operate the servo during the first test like in the previous run: making the arm stand still in the horizontal position, to achieve the maximum torque, then at the end of the test we go down and up again</li><br />
<li>we do the second test applying continuously this pattern of movements:<br />
<ul><br />
<li>5 up and down cycles, normal speed: period of approx. 3 seconds (2 second to go up, 1 second down)</li><br />
<li>1 up and down cycle, quick</li><br />
<li>10 seconds standing in a low stress position</li></ul><br />
</li></ul><br />
<br />
We've had these same results for both the test runs:<br />
<br />
Torque applied: 46.73 kgf*mm<br />
Final temperature: 41 °C<br />
Motion degradation: reasonably slower<br />
<br />
We can accept this new assessment, given the premises above regarding the continuous torque, and it's interesting to point out that this torque is circa 49% of the stall torque declared on the box of the servo.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12926Talk:Servomechanisms (aka "Servos")2011-01-26T19:25:27Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second test run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up our servo for a new test run: this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br />
Final temperature: 48 °C<br />
Motion degradation: significantly slower, but still effective to rotate and lift the weight<br />
<br />
On the temperature chart we see that the servo heating looks normal only during the first five minutes, and since the final motion degradation in not acceptable, we decide to reduce the applied torque.<br />
<br />
At the same time we redefine our testing procedure:<br />
<br />
<ul><li>we want to use something stable for keeping the servo in place during our test, like a bench vice - so we mount our servo on its support, which we have previously attached on a Item basic profile.<br />
This way we can use the bench vice of AIRLab to make the Item profile and everything stand still (instead of holding it manually on the table's edge) so we can focus on the testing activity</li><br />
<li>we use a lower force, by adopting a shorter arm, the one in the image, which has the advantage of not interfering with the cord during operations<br>[[Image:Servo_arm_148SH.jpg]]<br></li><br />
<li>we operate the servo during the first test like in the previous run: making the arm stand still in the horizontal position, to achieve the maximum torque, then at the end of the test we go down and up again</li><br />
<li>we do the second test applying continuously this pattern of movements:<br />
<ul><br />
<li>5 up and down cycles, normal speed: period of approx. 3 seconds (2 second to go up, 1 second down)</li><br />
<li>1 up and down cycle, quick</li><br />
<li>10 seconds standing in a low stress position</li><br />
<ul><br />
</li><br />
</ul><br />
<br />
We've had these same results for both the test runs:<br />
<br />
Torque applied: 46.73 kgf*mm<br />
Final temperature: 41 °C<br />
Motion degradation: reasonably slower<br />
<br />
We can accept this new assessment, given the premises above regarding the continuous torque, and it's interesting to point out that this torque is circa 49% of the stall torque declared on the box of the servo.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12925Talk:Servomechanisms (aka "Servos")2011-01-26T19:17:25Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second test run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up our servo for a new test run: this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br />
Final temperature: 48 °C<br />
Motion degradation: significantly slower, but still effective to rotate and lift the weight<br />
<br />
On the temperature chart we see that the servo heating looks normal only during the first five minutes, and since the final motion degradation in not acceptable, we decide to reduce the applied torque.<br />
<br />
At the same time we redefine our testing procedure:<br />
<br />
<ul><li>we want to use something stable for keeping the servo in place during our test, like a bench vice - so we mount our servo on its support, which we have previously attached on a Item element**.<br />
This way we can use the bench vice of AIRLab to hold the item element** still (instead of holding it manually on the table's edge) and we can focus on the testing activity</li><br />
<li>we use a lower force, by adopting a shorter arm, the one in the image, which has the advantage of not interfering with the cord during lifting movements<br>[[Image:Servo_arm_148SH.jpg]]<br></li><br />
<li>we do the first test making the arm stand still in the maximum torque position, as in the previous case, then at the end of the test we try to lift the weight</li><br />
<li>we do the second test applying a continuous pattern of movements, so defined<br />
<ul><br />
<li>5 up and down cycles, normal speed (approx 3 seconds, 2 sec up, 1 second down)</li><br />
<li>1 up and down cycle, quick</li><br />
<li>10 seconds standing in a low stress position</li><ul><br />
</li><br />
</ul><br />
<br />
We've had these same results for both the test runs:<br />
<br />
Torque applied: 46.73 kgf*mm<br />
Final temperature: 41 °C<br />
Motion degradation: reasonably slower<br />
<br />
We can accept this new assessment, given the premises above regarding the continuous torque, and it's interesting to point out that this torque is circa 49% of the stall torque declared on the box of the servo.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12924Talk:Servomechanisms (aka "Servos")2011-01-26T19:00:11Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second test run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up our servo for a new test run: this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br />
Final temperature: 48 °C<br />
Motion degradation: significantly slower, but still effective to rotate and lift the weight<br />
<br />
On the temperature chart we see that the servo heating seems normal during first five minutes.<br />
<br />
Inspired by the movement at the end of this test run, we decide to adopt a new, more rigorous **, testing approach:<br />
<br />
<ul><li>we want to use something stable for keeping the servo in place during our test, like a bench vice - so we mount our servo on its support **, which we have previously fixed on a Item element**.<br />
This way we can use our bench vice to hold the item element** still, instead of holding it on the table's edge, and we can focus on a more structured test</li><br />
<li>we use a lower force, by adopting a shorter arm, via the arm of this image, which has the advantage of not interfering with the cord during lifting movements [[Image:Servo_arm_148SH.jpg]]<br></li><br />
<li>we do the first test making the arm stand still in the maximum torque position, as in the previous case, then at the end of the test we try to lift the weight</li><br />
<li>we do the second test applying a continuous pattern of movements, so defined<br />
<ul><br />
<li>5 up and down cycles, normal speed (approx 3 seconds, 2 sec up, 1 second down)</li><br />
<li>1 up and down cycle, quick</li><br />
<li>10 seconds standing in a low stress position</li><ul><br />
</li><br />
</ul><br />
<br />
We decide that there is a new kind of test</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12923Talk:Servomechanisms (aka "Servos")2011-01-26T18:27:21Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
[[Image:Servo_arm_148SH.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second test run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up our servo for a new test run: this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br />
Final temperature: 48 °C<br />
Motion degradation: significantly slower, but still effective to rotate and lift the weight<br />
<br />
On the temperature chart we see that the servo heating seems normal during first five minutes.<br />
<br />
Inspired by the movement at the end of this test run, we decide to adopt a new, more rigorous **, testing approach:<br />
<br />
<ul><li>we want to use something stable for keeping the servo in place during our test, like a bench vice - so we mount our servo on its support **, which we have previously fixed on a Item element**.<br />
This way we can use our bench vice to hold the item element** still, instead of holding it on the table's edge, and we can focus on a more structured test</li><br />
<li>we use a lower force, by adopting a shorter arm, via the arm of this image, which has the advantage of nor interfering with the movements</li><br />
<li>we do the first test run normally</li><br />
<li>we do the second test run normally</li><br />
</ul><br />
<br />
We decide that there is a new kind of test</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12922Talk:Servomechanisms (aka "Servos")2011-01-26T18:12:38Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
[[Image:Servo_arm_148SH.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second test run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up our servo for a new test run: this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br />
Final temperature: 48 °C<br />
Motion degradation: significantly slower, but still effective to rotate and lift the weight<br />
<br />
On the temperature chart we see that the servo heating seems normal during first five minutes.<br />
<br />
Inspired by the movement at the end of this test run, we decide to adopt a new, more rigorous **, testing approach:<br />
<br />
<li><ul>we want to use something stable for keeping the servo in place during our test, like a bench vice - so we mount our servo on its support **, which we have previously fixed on a Item element**.<br />
This way we can use our bench vice to hold the item element** still, instead of holding it on the table's edge, and we can focus on a more structured test</ul><br />
<ul>we use a lower force, by adopting a shorter arm, via the arm of this image, which has the advantage of nor interfering with the movements<br>[[Image:Servo_arm_148SH.jpg]]</ul><br />
<ul>we do the first test run normally</ul><br />
<ul>we do the second test run normally</ul><br />
</li><br />
<br />
We decide that there is a new kind of test</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12921Talk:Servomechanisms (aka "Servos")2011-01-26T17:47:33Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
[[Image:Servo_arm_148SH.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.<br />
<br />
We've set up for a new run of our test, this time we're using a lower torque, annotating the temperature, and trying to rotate the shaft at the end of our test, to see the difference in movement - the results:<br />
<br />
Torque applied: 59.19 kgf*mm<br />
Final temperature: 48 °C<br />
Motion degradation: significantly slower, but still effective in lifting the weight<br />
<br />
On the temperature chart we see that the servo heating seems normal during first five minutes.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12920Talk:Servomechanisms (aka "Servos")2011-01-26T15:46:20Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
[[Image:Servo_arm_148SH.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=File:Servo_arm_148SH.jpg&diff=12919File:Servo arm 148SH.jpg2011-01-26T15:41:58Z<p>StefanoCapelli: </p>
<hr />
<div></div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12918Talk:Servomechanisms (aka "Servos")2011-01-25T11:51:30Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn (the red one in the image) on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their weight multiplied by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (OK?).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12917Talk:Servomechanisms (aka "Servos")2011-01-25T11:48:39Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''':<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12916Talk:Servomechanisms (aka "Servos")2011-01-25T11:48:28Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''';<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
<ul><li>opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
</li><li><br />
mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
</li><li><br />
arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.</li></ul><br />
<br />
''And we have assumed that:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
in the context of our robot's operation, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12915Talk:Servomechanisms (aka "Servos")2011-01-25T11:45:59Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''';<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<ul><li>we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
</li><li><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br />
</li></ul><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12914Talk:Servomechanisms (aka "Servos")2011-01-25T11:44:47Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
<span style="width:500px">aaa</span><br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''';<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12913Talk:Servomechanisms (aka "Servos")2011-01-25T11:44:17Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
<span width="500px">aaa</span><br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''';<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12912Talk:Servomechanisms (aka "Servos")2011-01-25T11:44:01Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
<span width="500px"></span><br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''';<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the ''continuous torque'' of HS-645MG.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12911Talk:Servomechanisms (aka "Servos")2011-01-25T11:41:53Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG''':<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB''';<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
[[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.19 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12910Talk:Servomechanisms (aka "Servos")2011-01-25T11:37:21Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]] [[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]] [[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site - contacted by us, one of Hitec's service managers wrote that the torque on the spec denotes the "stall torque" and to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.185 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12909Talk:Servomechanisms (aka "Servos")2011-01-25T11:25:42Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has currently adopted two types of servomechanisms to drive its mechanical parts.<br />
<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]] [[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]] [[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site: contacted by us, one of Hitec's service managers has denoted that spec as "stall torque", and told us to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.185 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12908Talk:Servomechanisms (aka "Servos")2011-01-25T11:25:07Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has adopted two kinds of servomechanisms as a means to drive its mechanical parts.<br />
<br />
Here they are:<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]] [[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]] [[Image:HITEC_HS-785HB.jpg]]<br><br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site: contacted by us, one of Hitec's service managers has denoted that spec as "stall torque", and told us to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.185 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12907Talk:Servomechanisms (aka "Servos")2011-01-25T11:24:43Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has adopted two kinds of servomechanisms as a means to drive its mechanical parts.<br />
<br />
Here they are:<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[Image:HITEC_HS-645MG.jpg]]<br><br />
[[Image:Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[Image:HS-785HB_with_drum.jpg]]<br />
<br><br />
[[Image:HITEC_HS-785HB.jpg]]<br />
<br><br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site: contacted by us, one of Hitec's service managers has denoted that spec as "stall torque", and told us to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.185 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12906Talk:Servomechanisms (aka "Servos")2011-01-25T11:23:57Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has adopted two kinds of servomechanisms as a means to drive its mechanical parts.<br />
<br />
Here they are:<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
[[HITEC_HS-645MG.jpg]]<br><br />
[[Servo_Hardware_Horns.gif]]<br><br />
<br />
'''HS-785HB'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
[[HS-785HB_with_drum.jpg]]<br />
<br><br />
[[HITEC_HS-785HB.jpg]]<br />
<br><br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site: contacted by us, one of Hitec's service managers has denoted that spec as "stall torque", and told us to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.185 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=File:HS-785HB_with_drum.jpg&diff=12905File:HS-785HB with drum.jpg2011-01-25T11:18:37Z<p>StefanoCapelli: </p>
<hr />
<div></div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=File:HITEC_HS-785HB.jpg&diff=12904File:HITEC HS-785HB.jpg2011-01-25T11:18:10Z<p>StefanoCapelli: </p>
<hr />
<div></div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=File:Servo_Hardware_Horns.gif&diff=12903File:Servo Hardware Horns.gif2011-01-25T11:17:54Z<p>StefanoCapelli: </p>
<hr />
<div></div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=File:HITEC_HS-645MG.jpg&diff=12902File:HITEC HS-645MG.jpg2011-01-25T11:16:58Z<p>StefanoCapelli: </p>
<hr />
<div></div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12901Talk:Servomechanisms (aka "Servos")2011-01-24T23:48:30Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has adopted two kinds of servomechanisms as a means to drive its mechanical parts.<br />
<br />
Here they are:<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
<br />
'''HS-785HB'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site: contacted by us, one of Hitec's service managers has denoted that spec as "stall torque", and told us to assume its 80 percent as continuous torque.<br />
<br />
''In order to test our servos we have done the following:''<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
<br/><br />
- mounted a horn on the shaft, then attached a wire at a known distance from the horn's center, using the farthest hole available on the horn. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will create the desired moment on the shaft<br />
<br/><br />
- arranged some objects (like bottles filled with water, wired together) with adjustable mass: their final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
''And we have assumed this:''<br />
<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br><br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br><br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.185 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12900Talk:Servomechanisms (aka "Servos")2011-01-24T20:06:28Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has adopted two kinds of servomechanisms as a means to drive its mechanical parts.<br />
<br />
Here they are:<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
<br />
'''HS-785HB'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site: contacted by us, one of Hitec's service managers has denoted that spec as "stall torque", and told us to assume its 80 percent as continuous torque.<br />
<br />
In order to test our servos we have done the following:<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
- mounted a horn on the shaft, to attach a wire. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will cause the desired moment on the shaft<br />
- arranged some objects (like water filled bottles, wired together) with adjustable weight: the final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
And assumed this:<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br />
<br />
So we've started our test, using Hitec's specification of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.185 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12899Talk:Servomechanisms (aka "Servos")2011-01-24T20:03:04Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has adopted two kinds of servomechanisms as a means to drive its mechanical parts.<br />
<br />
Here they are:<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
<br />
'''HS-785HB'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site: contacted by us, one of Hitec's service managers has denoted that spec as "stall torque", and told us to assume its 80 percent as continuous torque.<br />
<br />
In order to test our servos we have done the following:<br />
<br />
- opened the case of our servo and fitted a thermocouple near the circuitry, then closed it back<br />
- mounted a horn on the shaft, to attach a wire. The wire's end will be used to apply a force, which, using the horn as the lever's arm, will cause the desired moment on the shaft<br />
- arranged some objects (like water filled bottles, wired together) with adjustable weight: the final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
And assumed this:<br />
- we can apply a moment using a single force at an arm's end, thereby obtaining something different from a "pure" torque: our force induces rotation and translation, while a pure torque (a couple) causes only rotation.<br />
- in the context of our robot's functioning, a mere 10 minute's test time should be enough to characterize the tested torque as "continuous". In fact we may prevent prolonged stress for our servos via behavior rules - the basis for this is that we see no reason to keep the body in a completely bent configuration for more than a minute or two (VERIFY THIS).<br />
<br />
So we've started our test, using Hitec's designation of continuous torque (76.80 kgf*mm) as initial guess, and we've seen the measured temperature rising rapidly from 35° to 40° in the first three or four minutes of our test, so we've decided to abort this test, guessing that the actual temperature in the machinery/circuitry of our servo could be higher.<br />
<br />
We've prepared a second run with a lower torque (59.185 kgf*mm) and this time we've reached the same high temperature in 10 minutes, thereby deciding to adopt this second value as a better estimate of the "continuous" torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12898Talk:Servomechanisms (aka "Servos")2011-01-24T19:23:06Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has adopted two kinds of servomechanisms as a means to drive its mechanical parts.<br />
<br />
Here they are:<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with 90° shaft rotation (in the simplest configuration) or 180° with a special RC controller or using Hitec's servo stretcher.<br />
<br />
<br />
'''HS-785HB'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site: contacted by us, one of Hitec's service managers has denoted that spec as "stall torque", and told us to assume its 80 percent as continuous torque.<br />
<br />
In order to test our servo, we hatest Before our test we have follo<br />
Before testing, we have done the following:<br />
<br />
- opened the case of our servo, fitted thermocouple near the circuitry, then closed it back, with the four screws<br />
- mounted a horn on the shaft, to attach a wire. Then the wire's end will be used to apply a force, which, using the horn as the lever's arm, will apply a moment on the shaft<br />
- prepared some objects (like water filled bottles, wired together) with adjustable weight: the final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
<br />
Assuming that we can apply a moment using a single force, not a couple of forces equal in modulus (the real torque), we've started our test, using Hitec's designation of continuos torque () as initial guess.<br />
<br />
We've tried to provide that force to the horn of one the two servo models, to see what happens when the servo has to lift the mass and keep it still for some time: the measured temperature has risen from 25° to more than 40° in 4 minutes, and we've guessed that actual temperature could be so high as to suggest a lower value of continuous torque.<br />
<br />
We've made a second test using ... as the torque, and the same temperature rise has occurred in 10 minutes, which is a reasonable result to take this new value as our continuous torque estimation.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12897Talk:Servomechanisms (aka "Servos")2011-01-24T19:18:28Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has adopted two kinds of servomechanisms as a means to drive its mechanical parts.<br />
<br />
Here they are:<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with shaft angular movement ranging from -90° to +90°, or in the simplest configuration, 0°=>+90°.<br />
<br />
<br />
'''HS-645MG'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site: contacted by us, one of Hitec's service managers has denoted that spec as "stall torque", and told us to assume its 80 percent as continuous torque.<br />
<br />
In order to test our servo, we hatest Before our test we have follo<br />
Before testing, we have done the following:<br />
<br />
- opened the case of our servo, fitted thermocouple near the circuitry, then closed it back, with the four screws<br />
- mounted a horn on the shaft, to attach a wire. Then the wire's end will be used to apply a force, which, using the horn as the lever's arm, will apply a moment on the shaft<br />
- prepared some objects (like water filled bottles, wired together) with adjustable weight: the final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
<br />
Assuming that we can apply a moment using a single force, not a couple of forces equal in modulus (the real torque), we've started our test, using Hitec's designation of continuos torque () as initial guess.<br />
<br />
We've tried to provide that force to the horn of one the two servo models, to see what happens when the servo has to lift the mass and keep it still for some time: the measured temperature has risen from 25° to more than 40° in 4 minutes, and we've guessed that actual temperature could be so high as to suggest a lower value of continuous torque.<br />
<br />
We've made a second test using ... as the torque, and the same temperature rise has occurred in 10 minutes, which is a reasonable result to take this new value as our continuous torque estimation.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12896Talk:Servomechanisms (aka "Servos")2011-01-24T18:25:13Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has adopted two kinds of servomechanisms as a means to drive its mechanical parts.<br />
<br />
Here they are:<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with shaft angular movement ranging from -90° to +90°, or in the simplest configuration, 0°=>+90°.<br />
<br />
<br />
'''HS-645MG'''<br />
this is the bigger one, with shaft angular movement ranging from (-360°*2.5) to (-360°*2.5), two complete turns and a half per direction.<br />
<br />
<br />
Here we describe how we've tried to assess the continuous torque of one of these devices.<br />
<br />
Hitech gives a generic torque specification on the box of their servos and on their internet site: contacted by us, one of Hitec's service managers has denoted that spec as "stall torque", and told us to assume its 80 percent as continuous torque.<br />
<br />
In order to test our servo, we hatest Before our test we have follo<br />
Before testing, we have done the following:<br />
<br />
- opened the case of our servo, fitted thermocouple near the circuitry, then closed it back, with the four screws<br />
- mounted a wench on the shaft, to attach a wire. Then the wire's end will be used to apply a force, while the wench's arm will turn the force in a moment.<br />
- prepared some objects (like water filled bottles, wired together) with adjustable weight: the final weight, divided by the length of the winch's arm (19mm in our case) will equal the tested torque.<br />
<br />
<br />
Assuming that we can apply a moment using a single force, not a couple of forces equal in modulus (the real torque), we've started our test, using Hitec's designation of continuos torque () as initial guess.<br />
<br />
We've tried to provide that force to the wench of one the two servo models, to see what happens when the servo has to keep the weight still for some time: the measured temperature has risen from 25° to more than 40° in less than 5 minutes, and we've guessed that actual temperature could be so high as to suggest a lower value of continuous torque.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12895Talk:Servomechanisms (aka "Servos")2011-01-24T17:44:09Z<p>StefanoCapelli: </p>
<hr />
<div>The E-2? Robot project has adopted two kinds of servomechanisms as a means to drive its mechanical parts.<br />
<br />
Here they are:<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with shaft angular movement ranging from -90°=>+90°, or in the simplest configuration, 0°=>+90°.<br />
<br />
<br />
'''HS-645MG'''<br />
this is the smaller one, with shaft angular movement ranging from -90°=>+90°, or in the simplest configuration, 0°=>+90°.<br />
<br />
<br />
Here we describe the procedure adopted assess the continuous torque of these devices.<br />
<br />
Hitech gives an indication of the torque on the box of the servos and on their internet site: we have contacted them and they say that that torque is the stall torque, and the continuous torque is the 80 percent of that value.<br />
<br />
Starting from 80% of stall torque, we provide that moment for one of the two servo models, to test and see what happens.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:Servomechanisms_(aka_%22Servos%22)&diff=12894Talk:Servomechanisms (aka "Servos")2011-01-24T17:26:56Z<p>StefanoCapelli: New page: Andiamo qui a epsorre la modalità di misura adottata per stimare la coppia nominale dei servomeccanismi.</p>
<hr />
<div>Andiamo qui a epsorre la modalità di misura adottata per stimare la coppia nominale dei servomeccanismi.</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:E-2%3F_Body&diff=12821Talk:E-2? Body2011-01-03T18:24:20Z<p>StefanoCapelli: /* The second approach */</p>
<hr />
<div>== The first approach to the problem ==<br />
The body is made up of modules which allow the overall motion of body, while (possibily) preserving their self-sufficiency and separation in the structure.<br />
<br />
[[Image:E-2 neck 1.png]]<br />
<br/><br/><br />
The bottom and top modules are identical and, together, allow a -30 +60 degrees inclination of the body.<br />
<br/><br/><br />
[[Image:E-2 neck 3.png]]<br />
<br/><br/><br />
The middle module is not self sufficient or separated from the top and bottom modules, but relies on their structure to anchor its driver element.<br />
<br/><br/><br />
[[Image:E-2 neck 2.png]]<br />
<br/><br/><br />
== The second approach ==<br />
The three main configurations of E-2?'s Body, from a side view.<br/><br />
[[Image:E-2_Body_2nd_approach_1.png]]<br/><br />
<br/>This time the approach should be final, since the mechanisms involved in bending the neck are both defined and comprised of components we are already familiar with.<br/><br />
[[Image:E-2_Body_2nd_approach_2.png]]<br/><br />
<br/>Perspective of E-2?'s Body, bending forward<br/><br />
[[Image:E-2_Body_2nd_approach_3.png]]<br/><br />
<br/>Perspective of E-2?'s Body, bending back<br/><br />
[[Image:E-2_Body_2nd_approach_4.png]]<br/><br />
<br/>The back-and-forward bending module and (over) the lateral bending module<br/><br />
[[Image:E-2_Body_2nd_approach_5.png]]<br/><br />
<br/>Another perspective of the two modules<br/><br />
[[Image:E-2_Body_2nd_approach_6.png]]</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:E-2%3F_Body&diff=12820Talk:E-2? Body2011-01-03T18:15:15Z<p>StefanoCapelli: /* The second approach */</p>
<hr />
<div>== The first approach to the problem ==<br />
The body is made up of modules which allow the overall motion of body, while (possibily) preserving their self-sufficiency and separation in the structure.<br />
<br />
[[Image:E-2 neck 1.png]]<br />
<br/><br/><br />
The bottom and top modules are identical and, together, allow a -30 +60 degrees inclination of the body.<br />
<br/><br/><br />
[[Image:E-2 neck 3.png]]<br />
<br/><br/><br />
The middle module is not self sufficient or separated from the top and bottom modules, but relies on their structure to anchor its driver element.<br />
<br/><br/><br />
[[Image:E-2 neck 2.png]]<br />
<br/><br/><br />
== The second approach ==<br />
The three main configurations of E-2?'s Body, from a side view.<br/><br />
[[Image:E-2_Body_2nd_approach_1.png]]<br/><br />
<br/>This time the approach should be final, since the mechanisms involved in bending the neck are both defined and comprised of components we are already familiar with.<br/><br />
[[Image:E-2_Body_2nd_approach_2.png]]<br/><br />
<br/>Perspective of E-2?'s Body, bending forth<br/><br />
[[Image:E-2_Body_2nd_approach_3.png]]<br/><br />
<br/>Perspective of E-2?'s Body, bending back<br/><br />
[[Image:E-2_Body_2nd_approach_4.png]]<br/><br />
<br/>The back-and-forth bending module and (over) the lateral bending module<br/><br />
[[Image:E-2_Body_2nd_approach_5.png]]<br/><br />
<br/>Another perspective of the two modules<br/><br />
[[Image:E-2_Body_2nd_approach_6.png]]</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:E-2%3F_Body&diff=12819Talk:E-2? Body2011-01-03T18:12:06Z<p>StefanoCapelli: /* The second approach */</p>
<hr />
<div>== The first approach to the problem ==<br />
The body is made up of modules which allow the overall motion of body, while (possibily) preserving their self-sufficiency and separation in the structure.<br />
<br />
[[Image:E-2 neck 1.png]]<br />
<br/><br/><br />
The bottom and top modules are identical and, together, allow a -30 +60 degrees inclination of the body.<br />
<br/><br/><br />
[[Image:E-2 neck 3.png]]<br />
<br/><br/><br />
The middle module is not self sufficient or separated from the top and bottom modules, but relies on their structure to anchor its driver element.<br />
<br/><br/><br />
[[Image:E-2 neck 2.png]]<br />
<br/><br/><br />
== The second approach ==<br />
The three main configurations of E-2's Body, from a lateral view.<br/><br />
[[Image:E-2_Body_2nd_approach_1.png]]<br />
<br/>This time the approach may be final, since the mechanisms involved in bending the neck are both defined and comprised of components we are already familiar with.<br/><br />
[[Image:E-2_Body_2nd_approach_2.png]]<br />
<br/>E-2 Body's perspective, bending forth<br/><br />
[[Image:E-2_Body_2nd_approach_3.png]]<br />
<br/>E-2 Body's perspective, bending back<br/><br />
[[Image:E-2_Body_2nd_approach_4.png]]<br />
<br/>the back-and-forth bending module and (over) the lateral bending module<br/><br />
[[Image:E-2_Body_2nd_approach_5.png]]<br />
<br/>another perspective of the two modules<br/><br />
[[Image:E-2_Body_2nd_approach_6.png]]</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:E-2%3F_Body&diff=12818Talk:E-2? Body2011-01-03T18:04:51Z<p>StefanoCapelli: /* The second approach */</p>
<hr />
<div>== The first approach to the problem ==<br />
The body is made up of modules which allow the overall motion of body, while (possibily) preserving their self-sufficiency and separation in the structure.<br />
<br />
[[Image:E-2 neck 1.png]]<br />
<br/><br/><br />
The bottom and top modules are identical and, together, allow a -30 +60 degrees inclination of the body.<br />
<br/><br/><br />
[[Image:E-2 neck 3.png]]<br />
<br/><br/><br />
The middle module is not self sufficient or separated from the top and bottom modules, but relies on their structure to anchor its driver element.<br />
<br/><br/><br />
[[Image:E-2 neck 2.png]]<br />
<br/><br/><br />
== The second approach ==<br />
This is a overall view of E-2,bending back, normal position, and bending forth.<br/><br />
[[Image:E-2_Body_2nd_approach_1.png]]<br />
<br/>This time we have a "possible" solution, since both mechanisms involved in bending the neck are defined and comprised of components we are already familiar with.<br/><br />
[[Image:E-2_Body_2nd_approach_2.png]]<br />
<br/>Perspective of the neck, bending forth<br/><br />
[[Image:E-2_Body_2nd_approach_3.png]]<br />
<br/>Perspective of the neck, bending back<br/><br />
[[Image:E-2_Body_2nd_approach_4.png]]<br />
<br/>detail of the back and forth bending module and lateral bending module<br/><br />
[[Image:E-2_Body_2nd_approach_5.png]]<br />
<br/>detail of the back and forth bending module<br/><br />
[[Image:E-2_Body_2nd_approach_6.png]]</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:E-2%3F_Body&diff=12817Talk:E-2? Body2011-01-03T18:03:30Z<p>StefanoCapelli: /* The second approach */</p>
<hr />
<div>== The first approach to the problem ==<br />
The body is made up of modules which allow the overall motion of body, while (possibily) preserving their self-sufficiency and separation in the structure.<br />
<br />
[[Image:E-2 neck 1.png]]<br />
<br/><br/><br />
The bottom and top modules are identical and, together, allow a -30 +60 degrees inclination of the body.<br />
<br/><br/><br />
[[Image:E-2 neck 3.png]]<br />
<br/><br/><br />
The middle module is not self sufficient or separated from the top and bottom modules, but relies on their structure to anchor its driver element.<br />
<br/><br/><br />
[[Image:E-2 neck 2.png]]<br />
<br/><br/><br />
== The second approach ==<br />
This is a overall view of E-2,bending back, normal position, and bending forth.<br/><br />
[[Image:E-2_Body_2nd_approach_1.png]]<br />
<br/>A bit of perspective<br/><br />
[[Image:E-2_Body_2nd_approach_2.png]]<br />
<br/>This time we have a "possible" solution, since both mechanisms involved in bending the neck are defined and comprised of components we are already familiar with.<br/><br />
[[Image:E-2_Body_2nd_approach_3.png]]<br />
<br/>another perspective<br/><br />
[[Image:E-2_Body_2nd_approach_4.png]]<br />
<br/>detail of the back and forth bending module and lateral bending module<br/><br />
[[Image:E-2_Body_2nd_approach_5.png]]<br />
<br/>detail of the back and forth bending module<br/><br />
[[Image:E-2_Body_2nd_approach_6.png]]</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:E-2%3F_Body&diff=12816Talk:E-2? Body2011-01-03T18:02:36Z<p>StefanoCapelli: /* The second approach */</p>
<hr />
<div>== The first approach to the problem ==<br />
The body is made up of modules which allow the overall motion of body, while (possibily) preserving their self-sufficiency and separation in the structure.<br />
<br />
[[Image:E-2 neck 1.png]]<br />
<br/><br/><br />
The bottom and top modules are identical and, together, allow a -30 +60 degrees inclination of the body.<br />
<br/><br/><br />
[[Image:E-2 neck 3.png]]<br />
<br/><br/><br />
The middle module is not self sufficient or separated from the top and bottom modules, but relies on their structure to anchor its driver element.<br />
<br/><br/><br />
[[Image:E-2 neck 2.png]]<br />
<br/><br/><br />
== The second approach ==<br />
This is a overall view of E-2,bending back, normal position, and bending forth.<br/><br />
[[Image:E-2_Body_2nd_approach_1.png]]<br />
A bit of perspective<br/><br />
[[Image:E-2_Body_2nd_approach_2.png]]<br />
This time we have a "possible" solution, since both mechanisms involved in bending the neck are defined and comprised of components we are already familiar with.<br/><br />
[[Image:E-2_Body_2nd_approach_3.png]]<br />
another perspective<br/><br />
[[Image:E-2_Body_2nd_approach_4.png]]<br />
detail of the back and forth bending module and lateral bending module<br/><br />
[[Image:E-2_Body_2nd_approach_5.png]]<br />
detail of the back and forth bending module<br/><br />
[[Image:E-2_Body_2nd_approach_6.png]]</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:E-2%3F_Body&diff=12815Talk:E-2? Body2011-01-03T18:01:16Z<p>StefanoCapelli: /* The second approach */</p>
<hr />
<div>== The first approach to the problem ==<br />
The body is made up of modules which allow the overall motion of body, while (possibily) preserving their self-sufficiency and separation in the structure.<br />
<br />
[[Image:E-2 neck 1.png]]<br />
<br/><br/><br />
The bottom and top modules are identical and, together, allow a -30 +60 degrees inclination of the body.<br />
<br/><br/><br />
[[Image:E-2 neck 3.png]]<br />
<br/><br/><br />
The middle module is not self sufficient or separated from the top and bottom modules, but relies on their structure to anchor its driver element.<br />
<br/><br/><br />
[[Image:E-2 neck 2.png]]<br />
<br/><br/><br />
== The second approach ==<br />
This is a overall view of E-2,bending back, normal position, and bending forth.<br />
[[Image:E-2_Body_2nd_approach_1.png]]<br />
A bit of perspective<br />
[[Image:E-2_Body_2nd_approach_2.png]]<br />
This time we have a "possible" solution, since both mechanisms involved in bending the neck are defined and comprised of components we are already familiar with.<br />
[[Image:E-2_Body_2nd_approach_3.png]]<br />
another perspective<br />
[[Image:E-2_Body_2nd_approach_4.png]]<br />
detail of the back and forth bending module and lateral bending module<br />
[[Image:E-2_Body_2nd_approach_5.png]]<br />
detail of the back and forth bending module<br />
[[Image:E-2_Body_2nd_approach_6.png]]</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=Talk:E-2%3F_Body&diff=12814Talk:E-2? Body2011-01-03T17:50:42Z<p>StefanoCapelli: /* The first two approaches to the problem */</p>
<hr />
<div>== The first approach to the problem ==<br />
The body is made up of modules which allow the overall motion of body, while (possibily) preserving their self-sufficiency and separation in the structure.<br />
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[[Image:E-2 neck 1.png]]<br />
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The bottom and top modules are identical and, together, allow a -30 +60 degrees inclination of the body.<br />
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[[Image:E-2 neck 3.png]]<br />
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The middle module is not self sufficient or separated from the top and bottom modules, but relies on their structure to anchor its driver element.<br />
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[[Image:E-2 neck 2.png]]<br />
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== The second approach ==<br />
[[Image:E-2_Body_2nd_approach_1.png]]<br />
[[Image:E-2_Body_2nd_approach_2.png]]<br />
[[Image:E-2_Body_2nd_approach_3.png]]<br />
[[Image:E-2_Body_2nd_approach_4.png]]<br />
[[Image:E-2_Body_2nd_approach_5.png]]<br />
[[Image:E-2_Body_2nd_approach_6.png]]</div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=File:E-2_Body_2nd_approach_6.png&diff=12813File:E-2 Body 2nd approach 6.png2011-01-03T17:38:09Z<p>StefanoCapelli: </p>
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<div></div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=File:E-2_Body_2nd_approach_5.png&diff=12812File:E-2 Body 2nd approach 5.png2011-01-03T17:37:52Z<p>StefanoCapelli: </p>
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<div></div>StefanoCapellihttps://airwiki.elet.polimi.it/index.php?title=File:E-2_Body_2nd_approach_4.png&diff=12811File:E-2 Body 2nd approach 4.png2011-01-03T17:37:34Z<p>StefanoCapelli: </p>
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<div></div>StefanoCapelli