ROS 1和2需要零代码！

现在，您已经安装了代理，每次运行ROS并开始将数据上传到Freedom时，ROS Shadow节点都会打开。

ROS 1和ROS 2

如果要使用启动脚本，播放ROS程序包或运行ROS节点，则无需执行其他任何操作。您的数据将自动开始上传到云端！在这里，我们将通过一个最小的示例向您展示更多有关其工作原理的信息。

没有ROS吗？

Freedom自动旋转一个节点（名为link_ros）以自省使用ROS发布的主题。启动某些内容并开始发布以进行检查-ROS袋也可以工作！

数据将显示在STREAM仪表板的Freedom App中。

ROS2：

   

    

     

      

     
     

      

       # Launch your own nodes and the Agent will automatically
      
     
    

     

      

     
     

      

       # start a node (link_ros) that listens to what is published.
      
     
    

     

      

     
     

      

       # Make sure to source your ROS workspace before launching. 
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       ros2 launch my_package my_launch.launch
      
     
   
  

ROS2 Bag：

   

    

     

      

     
     

      

       # Not many good quality ROS2 bags exist yet - here we show a
      
     
    

     

      

     
     

      

       # workaround with a ROS1 bag run in ROS2
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       # Make sure you have installed ros2 bag packages
      
     
    

     

      

     
     

      

       apt-get update
      
     
    

     

      

     
     

      

       sudo apt-get install ros-dashing-ros2bag-* ros-dashing-rosbag2*
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       # Source ROS1 workspace first
      
     
    

     

      

     
     

      

       source /opt/ros/melodic/setup.bash
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       # Now source ROS2 workspace
      
     
    

     

      

     
     

      

       source /opt/ros/dashing/setup.bash
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       # Download a ROS bag to play, saving it as rosbag-example.bag
      
     
    

     

      

     
     

      

       curl -L -o rosbag-example.bag https://bit.ly/freedom-rosbag-example-car
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       # Play the ROS bag and the Agent will listen to the topics it publishes
      
     
    

     

      

     
     

      

       ros2 bag play -s rosbag_v2 rosbag-example.bag
      
     
   
  

发送和接收消息

我们将通过一个示例演示ROS节点如何既可以将消息发送到Freedom，又可以响应从Freedom API发送的命令。

创建一个名为的文件，demo_node.py并复制下面的代码。

ROS2：

   

    

     

      

     
     

      

       #!/usr/bin/env python
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       # Please note that there are no references to Freedom in this ROS node.
      
     
    

     

      

     
     

      

       # The ROS Shadow node will automatically interact with this node and 
      
     
    

     

      

     
     

      

       # stream the data.
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       import time
      
     
    

     

      

     
     

      

       import rclpy
      
     
    

     

      

     
     

      

       import rclpy.logging
      
     
    

     

      

     
     

      

       from std_msgs.msg import String
      
     
    

     

      

     
     

      

       from sensor_msgs.msg import NavSatFix
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       logger = rclpy.logging.get_logger('node_logger')
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       # Create a callback to handle this topic
      
     
    

     

      

     
     

      

       def callback(data):
      
     
    

     

      

     
     

      

        logger.info("I heard {}".format(data.data))
      
     
    

     

      

     
     

      
 if data.data == "mission":
      
     
    

     

      

     
     

      

        logger.info("Running mission...")
      
     
    

     

      

     
     

      
 elif data.data == "shutdown":
      
     
    

     

      

     
     

      

        logger.info("Received shutdown command")
      
     
    

     

      

     
     

      

        rclpy.shutdown()
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       # There is nothing you need to do. The ROS Shadow node 
      
     
    

     

      

     
     

      

       # will automatically start when this starts
      
     
    

     

      

     
     

      

       if __name__ == '__main__':
      
     
    

     

      

     
     

      

        rclpy.init()
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

        node = rclpy.create_node('node_name')
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

        subscription = node.create_subscription(String, 'commands', callback, 10)
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      
 # Create our satellite GPS location topic
      
     
    

     

      

     
     

      

        pub_nav = node.create_publisher(NavSatFix, 'location', 10)
      
     
    

     

      

     
     

      

        nav_msg = NavSatFix(latitude=37.778454, longitude=-122.389171)
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

        rclpy.spin(node)
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      
 while rclpy.ok():
      
     
    

     

      

     
     

      

        pub_nav.publish(nav_msg)
      
     
    

     

      

     
     

      

        time.sleep(1)
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      
 # Destroy the node explicitly
      
     
    

     

      

     
     

      
 # (optional - otherwise it will be done automatically
      
     
    

     

      

     
     

      
 # when the garbage collector destroys the node object)
      
     
    

     

      

     
     

      

        node.destroy_node()
      
     
    

     

      

     
     

      

        rclpy.shutdown()
      
     
   
  

使用以下命令启动节点。

   

    

     

      

     
     

      

       # Source ROS2 workspace
      
     
    

     

      

     
     

      

       source /opt/ros/dashing/setup.bash
      
     
    

     

      

     
     

      
 
      
     
    

     

      

     
     

      

       # Execute created script with python3 (mandatory for ROS2)
      
     
    

     

      

     
     

      

       python3 demo_node.py