Difference between revisions of "ROS summary"

Revision as of 18:12, 15 March 2013

This page is dedicated to experienced ROS users. Its purpose is to provide a brief summary of the most useful commands and configurations for ROS and for the external programs, with few additional explanations.

This page should not be used to provide general-purpose information about ROS or its elements, which is the task of ROS HOWTO and its secondary AIRWiki pages (e.g., ROS packages, ROS commands or ROS components).

Please note that some of the most commonly used commands are already described in a condensed form in the ROS Official Cheat Sheet.

ROS and IDE initial setup

Configure your environment

If you followed the ROS tutorial to configure your environment, the variable $ROS_PACKAGE_PATH should be set. This can be easily verified by check if the command echo $ROS_PACKAGE_PATH returns an output similar to:

/home/your_user_name/fuerte_workspace/sandbox:/opt/ros/<ROS DISTRIBUTION>/share:/opt/ros/<ROS DISTIBUTION>/stacks

If you use a different path (e.g.: ~/eclipse_workspace) you should add it to the $ROS_PACKAGE_PATH variable. The simplest way to achieve this is to edit the .bashrc file located in your home directory and add the line

export ROS_PACKAGE_PATH=~/eclipse_workspace:${ROS_PACKAGE_PATH}

NOTE: Please be sure to add this command AFTER the following line (that you should have added to your .bashrc, according to the tutorial) or you will get an error running make eclipse-project:

source /opt/ros/<ROS DISTIBUTION>/setup.bash

Eclipse

• To reuse your shell environment it is advisable to launch Eclipse with the following command:

bash -i -c /usr/lib/eclipse/eclipse

• To let ROS create the Eclipse project files you can use the following command:

make eclipse-project

Note that if you change anything to your manifest.xml, you will have to run this script again, which will overwrite your Eclipse project file and thereby reverting all manual changes to the project settings. Please refer to this page if you need further information.

• To add an existing project to Eclipse select File --> Import --> General --> Existing Projects into Workspace, select the project's root directory and be sure that the "Copy projects into workspace" option is NOT selected.

Package management

ROS packages can be managed using your linux distribution package manager and/or with the built-in ROS package manager.

ROS package environment

• To initialize the ROS package management environment:

(as root) rosdep init

• To update the package list:

rosdep update

ROS package installation

• To find a package:

browse to this page to browse a list of available packages.

• To check if a ROS package or stack is installed, use the following commands:

rospack find package_name

rosstack find [stack_name]

If you get an error, install the stack that contains the package with the package manager of your linux distribution (e.g.: sudo apt-get install ros-distribution_release_name-stack_name ), then check again if rospack can find the package. If not, install it with the command:

(as root) rosdep install package_name

New package creation

This command creates a new package in the current directory:

roscreate-pkg package_name package_dependency_1 package_dependency_2 package_dependency_3 ...

Please note that package dependencies can be explicitly specified when the package is created, but they can also be manually added afterwards to the manifest.xml file or with the rospack command. Take a look at this page if you need further information.

CMakeLists.txt

Official pages:
Full description of the syntax
Examples.

cmake_minimum_required(VERSION 2.4.6)
include($ENV{ROS_ROOT}/core/rosbuild/rosbuild.cmake)

# Set the build type.  Options are:
#  Coverage       : w/ debug symbols, w/o optimization, w/ code-coverage
#  Debug          : w/ debug symbols, w/o optimization
#  Release        : w/o debug symbols, w/ optimization
#  RelWithDebInfo : w/ debug symbols, w/ optimization
#  MinSizeRel     : w/o debug symbols, w/ optimization, stripped binaries
# Usage:
#     set(ROS_BUILD_TYPE build_type)
set(ROS_BUILD_TYPE Debug)

rosbuild_init()

# Set the default path for built executables to the "bin" directory
set(EXECUTABLE_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/bin)
# Set the default path for built libraries to the "lib" directory
set(LIBRARY_OUTPUT_PATH ${PROJECT_SOURCE_DIR}/lib)

# Uncomment if you have defined messages
#rosbuild_genmsg()

# Uncomment if you have defined services
#rosbuild_gensrv()

# **** Common commands for building c++ executables and libraries ****

# To add an executable cpp file: 
# Usage:
#     rosbuild_add_executable(${PROJECT_NAME} executable_path)
rosbuild_add_executable(test_read_map src/test_read_map.cpp)

# To add a library:
# Usage:
#     rosbuild_add_library(${PROJECT_NAME} libraries_path)
rosbuild_add_library(map
                    src/map/map_cspace.cpp
                    src/map/map_draw.c)

# To link a library to an executable file:
# Usage:
#     target_link_libraries(${PROJECT_NAME} library_name)
target_link_libraries(test_read_map map)

# To add boost directories:
# rosbuild_add_boost_directories()

# To link boost:
# rosbuild_link_boost(${PROJECT_NAME} thread)

# To add the dynamic reconfigure api:
# rosbuild_find_ros_package(dynamic_reconfigure)
# include(${dynamic_reconfigure_PACKAGE_PATH}/cmake/cfgbuild.cmake)
# gencfg()
# rosbuild_add_executable(dynamic_reconfigure_node src/dynamic_reconfigure_node.cpp)
# rosbuild_add_executable(FIRST_dynamic_reconfigure_node src/FIRST_dynamic_reconfigure_node.cpp)

Makefile

Be sure that the following line is present in the Makefile in order for the command make eclipse-project to work:

include $(shell rospack find mk)/cmake.mk

Manifest.xml

<package>
  <description brief="brief description of your package">

     [write here your package name]

  </description>
  <author>Your name</author>
  <license>BSD</license>
  <review status="unreviewed" notes=""/>
  <url>http://ros.org/wiki/package_name</url>
  <depend package="package dependance 1"/>
  <depend package="package dependance 2"/>
  ....
</package>

ROS commands

ROS Filesystem

• To change directory directly to a package or stack directory:

roscd package_name

or

roscd stack_name

External programs

rviz (ROS visualization system)

• To open rviz you will need roscore running in background (execute roscore in a different shell) and then run the following command:

rosrun rviz rviz

The rviz interface will pop up, to visualize something published by a node you will have to

• Add a type by clicking Add and selecting a display type (e.g.: poing cloud)
• Set the topic that you want to listen (the one specified in the node that is publishing)
• Set in the Global Options menu the desired Fixed Frame (typically /map )

Gazebo wrapped into Groovy (a.k.a. Questo matrimonio non s'ha da fare)

Don't waste your time trying to execute the tutorials available on the ROS website!! They are outdated and will almost surely not work in every ROS distribution later than electric. (Source). You can (almost) safely follow Gazebo's tutorials the gazebo standalone's tutorials, but be sure to select the right tutorials for the version of Gazebo included in your distribution of ROS (as of 15 March 2013, Groovy --> Gazebo 1.3) and to follow the following instructions.

How to correctly setup a Gazebo package with a plugin inside Groovy

Note: the following supposes a working and correctly configured ROS environment (follow the ROS official installation guide otherwise)

We use the Control model tutorial of gazebo standalone, as an example to show what to do to successfully complete Gazebo standalone's tutorials in the ROS-wrapped gazebo.

1. Create the ROS package, specifying the dependency on gazebo, and open it: roscreate-pkg gazebo_control_model gazebo; cd gazebo_control_model/
2. Create the .world file and the plugin file, as specified in the tutorial
3. Look for the <plugin> tag in the world file and modify the filename property adding "lib/" (without quotes) before the filename (e.g., from filename="libcontrol_model.so" to filename="lib/libcontrol_model.so")
4. Open the CMakeLists.txt file and add at the end rosbuild_add_library(control_model SHARED control_model.cc)
5. Create the build folder mkdir build; cd build
6. Run cmake and make cmake ..; make
7. Download and extract the following script in the package directory (in the main one, not under build), open it with your favorite text editor and modify the package_filename variable with the name of your package ("gazebo_control_model" in this example). Finally make it executable and run it: chmod ugoa+x zzz_launchers_generator.sh; ./zzz_launchers_generator.sh
8. The script will create two files, you can open your gazebo model just executing the launcher file

Interesting links for the future (to be tested)

This discussion proposes a method to use Gazebo's models included with Groovy and this one cites some model that seem to be working with the ROS-wrapped-Gazebo.

Common error messages

• Trying to execute the wrapped-into-Groovy Gazebo, you could encounter the following error:

Error [Rendering.cc:37] Failed to load the Rendering engine subsystem unable to find OpenGL rendering system. OGRE is probably installed incorrectly. Double check the OGRE cmake output, and make sure OpenGL is enabled

This can be due to two different issues:

1. The OGRE's package is not correctly installed: in this case install ogre with sudo apt-get install ros-groovy-visualization-common
2. The OGRE_RESOURCE_PATH variable is not correctly set in ROS: to solve this problem you will have to modify the "export OGRE_RESOURCE_PATH" in /opt/ros/groovy/stacks/simulator_gazebo/gazebo/scripts/setup.sh (potentially also in /opt/ros/groovy/stacks/simulator_gazebo/gazebo/setup.bash) with the correct OGRE path. This is usually located in one of the following folders:

/usr/lib/OGRE

/usr/lib/x86_64-linux-gnu/OGRE-1.7.4

/usr/lib/i386-linux-gnu/OGRE-1.7.4

Further information please refer to Gazebo answers

• Trying to spawn a model in gazebo, you could end up stuck with the following message forever:

waiting for service /gazebo/spawn_urdf_model

In this case the namespace could be wrong, try to specify the "gazeborver" namespace at the end of your spawing command, e.g.:

rosrun gazebo spawn_model -file object.urdf -urdf -model my_object -gazebo_namespace gazeborver

• Trying to spawn a model in gazebo, following the tutorial, you could receive an error like this:

Invalid <param> tag: Cannot load command parameter [table_description]: no such command [/opt/ros/groovy/share/xacro/xacro.py /opt/ros/groovy/stacks/simulator_gazebo/gazebo_worlds/objects/table.urdf.xacro].

Solution: as stated at the very beginning of this section, don't follow the tutorials on the ROS website!!