[PC_HOST]/[RPI] Codage avec ROS2

[PC_HOST]/[RPI] Codage avec ROS2

Les exemples ci-dessous reprennent ceux du tutoriel ROS2

node1.svg

Echange de messages en local ( C++ )

resume_ros2.svg

Creation d’un package

mkdir -p ~/ros2_ws/src 	# Creation d'un workspace ros2_ws
cd ~/ros2_ws/src  		
ros2 pkg create --build-type ament_cmake cpp_pubsub

Ecriture du publisher et du subscriber node

cd ~/ros2_ws/src/cpp_pubsub/src
wget -O publisher_member_function.cpp https://raw.githubusercontent.com/ros2/examples/humble/rclcpp/topics/minimal_publisher/member_function.cpp
wget -O subscriber_member_function.cpp https://raw.githubusercontent.com/ros2/examples/humble/rclcpp/topics/minimal_subscriber/member_function.cpp

Modification de package.xml

cd ~/ros2_ws/src/cpp_pubsub  
nano package.xml  
<?xml version="1.0"?>
<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
<package format="3">
  <name>cpp_pubsub</name>
  <version>0.0.0</version>
  <description>TODO: Package description</description>
  <maintainer email="kerhoas@enib.fr">kerhoas</maintainer>
  <license>TODO: License declaration</license>

  <buildtool_depend>ament_cmake</buildtool_depend>
  
<!-- #################################################### -->
  <depend>rclcpp</depend>   <!-- A AJOUTER -->
  <depend>std_msgs</depend> <!-- A AJOUTER -->
<!-- #################################################### -->
 
  <test_depend>ament_lint_auto</test_depend>
  <test_depend>ament_lint_common</test_depend>

  <export>
    <build_type>ament_cmake</build_type>
  </export>
</package>

Modification de CMakeLists.txt

cd ~/ros2_ws/src/cpp_pubsub  
nano CMakeLists.txt   
cmake_minimum_required(VERSION 3.5)
project(cpp_pubsub)

# Default to C99
if(NOT CMAKE_C_STANDARD)
  set(CMAKE_C_STANDARD 99)
endif()

# Default to C++14
if(NOT CMAKE_CXX_STANDARD)
  set(CMAKE_CXX_STANDARD 14)
endif()

if(CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
  add_compile_options(-Wall -Wextra -Wpedantic)
endif()

# find dependencies
find_package(ament_cmake REQUIRED)
#######################################################################
find_package(rclcpp REQUIRED)			# A AJOUTER
find_package(std_msgs REQUIRED)			# A AJOUTER

# uncomment the following section in order to fill in
# further dependencies manually.
# find_package(<dependency> REQUIRED)

add_executable(talker src/publisher_member_function.cpp) 	# A AJOUTER
ament_target_dependencies(talker rclcpp std_msgs)			# A AJOUTER

add_executable(listener src/subscriber_member_function.cpp)	# A AJOUTER
ament_target_dependencies(listener rclcpp std_msgs)			# A AJOUTER

install(TARGETS							# A AJOUTER
  talker
  listener
  DESTINATION lib/${PROJECT_NAME}) 	
#######################################################################

  
if(BUILD_TESTING)
  find_package(ament_lint_auto REQUIRED)
  ament_lint_auto_find_test_dependencies()
endif()  		

Build and Run

cd ~/ros2_ws
rosdep install -i --from-path src --rosdistro humble -y
colcon build --packages-select cpp_pubsub
. install/setup.bash
ros2 run cpp_pubsub talker

Dans un autre terminal :

cd ~/ros2_ws
. install/setup.bash
ros2 run cpp_pubsub listener

Clean

cd ~/ros2_ws
rm -rv install build log

Echange de messages en local ( Python )

Creation d’un package

mkdir -p ~/ros2_ws/src 	# Creation d'un workspace ros2_ws
cd ~/ros2_ws/src  		
ros2 pkg create --build-type ament_python py_pubsub

Ecriture du publisher et du subscriber node

cd ~/ros2_ws/src/py_pubsub/py_pubsub
wget https://raw.githubusercontent.com/ros2/examples/humble/rclpy/topics/minimal_publisher/examples_rclpy_minimal_publisher/publisher_member_function.py
wget https://raw.githubusercontent.com/ros2/examples/humble/rclpy/topics/minimal_subscriber/examples_rclpy_minimal_subscriber/subscriber_member_function.py

Modification de package.xml

cd ~/ros2_ws/src/py_pubsub 
nano package.xml
<?xml version="1.0"?>
<?xml-model href="http://download.ros.org/schema/package_format3.xsd" schematypens="http://www.w3.org/2001/XMLSchema"?>
<package format="3">
  <name>py_pubsub</name>
  <version>0.0.0</version>
  <description>TODO: Package description</description>
  <maintainer email="kerhoas@todo.todo">kerhoas</maintainer>
  <license>TODO: License declaration</license>

<!-- #################################################### -->
  <exec_depend>rclpy</exec_depend>      <!-- A AJOUTER -->
  <exec_depend>std_msgs</exec_depend>   <!-- A AJOUTER -->
<!-- #################################################### -->

  <test_depend>ament_copyright</test_depend>
  <test_depend>ament_flake8</test_depend>
  <test_depend>ament_pep257</test_depend>
  <test_depend>python3-pytest</test_depend>

  <export>
    <build_type>ament_python</build_type>
  </export>
</package>

Modification de setup.py

cd ~/ros2_ws/src/py_pubsub  
nano setup.py 
from setuptools import setup

package_name = 'py_pubsub'

setup(
    name=package_name,
    version='0.0.0',
    packages=[package_name],
    data_files=[
        ('share/ament_index/resource_index/packages',
            ['resource/' + package_name]),
        ('share/' + package_name, ['package.xml']),
    ],
    install_requires=['setuptools'],
    zip_safe=True,
    maintainer='kerhoas',
    maintainer_email='kerhoas@enib.fr',
    description='TODO: Package description',
    license='TODO: License declaration',
    tests_require=['pytest'],
    entry_points={
        'console_scripts': [
                        'talker = py_pubsub.publisher_member_function:main',    # A AJOUTER
                        'listener = py_pubsub.subscriber_member_function:main', # A AJOUTER
        ],
    },
)

Build and Run

cd ~/ros2_ws
rosdep install -i --from-path src --rosdistro humble -y
colcon build --packages-select py_pubsub
. install/setup.bash
ros2 run py_pubsub talker

Dans un autre terminal :

cd ~/ros2_ws
. install/setup.bash
ros2 run py_pubsub listener 

Clean

cd ~/ros2_ws
rm -rv install build log

RQT

rqt est une interface graphique permettant d’analyser le réseau ROS2.

rqt

rqt.png