Micro-XRCE-DDS-Client/docs/samples.md

示例程序

examples/example_uros.c: 包含了uros ping-pong的实例代码。Client端(BSP)订阅/microROS/ping消息，收到消息后，发送/microROS/pong消息到Agent端(ROS2).

准备工作

• 在Ubuntu 20.04 LTS上安装ROS 2 Foxy FitzRoy，参考链接

• 安装完ROS2后，使用如下指令安装Micro-ROS

  # Source the ROS 2 installation
  source /opt/ros/foxy/setup.bash
  
  # Create a workspace and download the micro-ROS tools
  mkdir microros_ws
  cd microros_ws
  git clone -b $ROS_DISTRO https://github.com/micro-ROS/micro_ros_setup.git src/micro_ros_setup
  
  # Update dependencies using rosdep
  sudo apt update && rosdep update
  rosdep install --from-path src --ignore-src -y
  
  # Install pip
  sudo apt-get install python3-pip
  
  # Build micro-ROS tools and source them
  colcon build
  source install/local_setup.bash
  

• 创建Micro-ROS Agent

  # Download micro-ROS-Agent packages
  ros2 run micro_ros_setup create_agent_ws.sh
  # Build step
  ros2 run micro_ros_setup build_agent.sh
  source install/local_setup.bash
  

• 运行Micro-ROS Agent

  • UDP: ros2 run micro_ros_agent micro_ros_agent udp4 --port 8888
  • TCP: ros2 run micro_ros_agent micro_ros_agent tcp4 --port 8888
  • Serial: ros2 run micro_ros_agent micro_ros_agent serial --dev [device]

运行示例

• 配置menuconfig使能Micro-XRCE-DDS-Client软件包并包含示例代码
• pkgs --update获取软件包代码
• 编译运行bsp/qemu-vexpress-a9
• 在控制台输入uros_test指令
• 如果成功将创建跟Micro-ROS Agent的连接，并等待/microROS/ping的消息

• 在电脑上打开新的终端，输入如下指令监听/microROS/pong。注意这时还没有消息发过来，因为还未发送ping指令给Client

  source /opt/ros/foxy/setup.bash
  ros2 topic echo /microROS/pong
  

• 打开另外一个新的终端，输入如下指令，发送/microROS/ping消息给Client端

  source /opt/ros/foxy/setup.bash
  # Send a fake ping
  ros2 topic pub /microROS/ping std_msgs/msg/Header '{frame_id: "fake_ping"}'
  

示例结果

RTT控制台输出结果:

msh />uros_test
Micro-ROS ping-pong demo.
msh />Wait for ping topic
Received topic: fake_ping, sec: 0
Send pong topic: Hello RT-Thread!, sec: 120
Received topic: fake_ping, sec: 0
Send pong topic: Hello RT-Thread!, sec: 121
Received topic: fake_ping, sec: 0
Send pong topic: Hello RT-Thread!, sec: 122
Received topic: fake_ping, sec: 0
Send pong topic: Hello RT-Thread!, sec: 123

终端输出结果：

~/src/microros_ws$ ros2 topic echo /microROS/pong
stamp:
  sec: 120
  nanosec: 450000000
frame_id: Hello RT-Thread!
---
stamp:
  sec: 121
  nanosec: 450000000
frame_id: Hello RT-Thread!
---
stamp:
  sec: 122
  nanosec: 450000000
frame_id: Hello RT-Thread!
---
stamp:
  sec: 123
  nanosec: 450000000
frame_id: Hello RT-Thread!
---