Welcome to MicroROS Robot Expansion Board repository
Robot information release
Robot information release
Note: The virtual machine needs to be in the same LAN as the car, and the ROS_DOMAIN_ID needs to be consistent. You can check [Must read before use] to set the IP and ROS_DOMAIN_ID on the board.
1. Program function description
After the car is connected to the agent, it will publish sensor data such as radar and imu. You can run commands in the supporting virtual machine/Raspberry Pi 5 to query this information. You can also publish control data of sensors such as speed and buzzer.
2. Query car information
2.1. Start and connect to the agent
Taking the supporting virtual machine as an example, enter the following command to start the agent:
sudo docker run -it --rm -v /dev:/dev -v /dev/shm:/dev/shm --privileged --net=host microros/micro-ros-agent:humble udp4 --port 8090 -v4
Then, turn on the car switch and wait for the car to connect to the agent. The connection is successful, as shown in the figure below.
2.2. Query the car node information
Enter the following command in the terminal to query the node,
xxxxxxxxxxros2 node list
Then enter the following command to query which topics the node has published/subscribed to,
xxxxxxxxxxros2 node info /YB_Car_Node
It can be seen that the topics subscribed to include:
/beep：Buzzer control
/cmd_vel：Car speed control
/servo_s1：s1 servo gimbal control
/servo_s2：s2 servo gimbal control
Posted topics include:
/imu：imu module data
/odom：Odometer module data
/scan：Radar module data
We can also query the topic command and enter it in the terminal,
xxxxxxxxxxros2 topic list
2.3. Query topic data
Query radar data,
xxxxxxxxxxros2 topic echo /scan
Query imu data,
xxxxxxxxxxros2 topic echo /imu
Query odom data,
xxxxxxxxxxros2 topic echo /odom_raw
3. Publish car control information
3.1. Control the buzzer
First, query the relevant information about the following buzzer topics, enter it in the terminal,
xxxxxxxxxxros2 topic info /beep
Learn that the data type is std_msgs/msg/UInt16. Then enter the following command to turn on the buzzer and enter in the terminal,
xxxxxxxxxxros2 topic pub /beep std_msgs/msg/UInt16 "data: 1"
Enter the following command to turn off the buzzer, terminal input,
xxxxxxxxxxros2 topic pub /beep std_msgs/msg/UInt16 "data: 0"
3.2. Release speed control information
We assume that the released car moves at a linear speed of 0.5 and an angular speed of 0.2, and the terminal input is,
xxxxxxxxxxros2 topic pub /cmd_vel geometry_msgs/msg/Twist "{linear: {x: 0.5, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.2}}"
If parking, enter
xxxxxxxxxxros2 topic pub /cmd_vel geometry_msgs/msg/Twist "{linear: {x: 0.0, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.0}}"
3.3. Control the gimbal servo
What needs to be noted here is that the range of s1 servo is [-90,90], and the range of s2 servo is [-90,20]. If the value exceeds the range, the servo will not rotate.
We assume that the s1 servo is controlled to rotate 30 degrees, and the terminal input is,
xxxxxxxxxxros2 topic pub /servo_s1 std_msgs/msg/Int32 "data: 30"
In the same way, if the s2 servo is controlled to rotate -30 degrees, the terminal input will be
xxxxxxxxxxros2 topic pub /servo_s2 std_msgs/msg/Int32 "data: -30"
