6 example 举例
ORDER1: ros2 run turtlesim turtlesim_node
//run turtle 运行小乌龟
open anther window 打开另外一个窗口
ORDER2: ros2 topic pub /turtle1/cmd_vel geometry_msgs/msg/Twist “{linear: {x: 1.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.0}}”
//小乌龟画圈 见效果图

//run turtle as line see in picture 让小乌龟按线性前进 效果见截图 
ORDER3: ros2 topic echo /turtle1/pose
//listen turtle postion see in picture
监听小乌龟坐标 效果见截图 