ROS2 Control For VESC (motor controller) not working with two VESCs

[Persius48]

Hello Evryone
I am currently working on a project to make a four-wheeled differential drive robot using 4 VESCs with ROS2 as the means of communication. Two vesc will be masters and the rest two will be slaves. I found the vesc_hw_interface in which I used for one VESC and it was okay. But when I tried to use two VESCs with some modification in the ros2_control_xacro by including two hardware and two joints, there was an error like the following

Invalid checksum [ros2_control_node-1] [ERROR] [1693755709.123338959] [VescHwInterface]: Out-of-sync with VESC, discarding 49 bytes. [ros2_control_node-1] [ERROR] [1693755709.128419540] [VescHwInterface]: Invalid end-of-frame character [ros2_control_node-1] [ERROR] [1693755709.128438065] [VescHwInterface]: Invalid payload length [ros2_control_node-1] [ERROR] [1693755709.128448735] [VescHwInterface]: Out-of-sync with VESC, discarding 21 bytes. [ros2_control_node-1] [ERROR] [1693755709.163161253] [VescHwInterface]: Invalid end-of-frame character [ros2_control_node-1] [ERROR] [1693755709.163192823] [VescHwInterface]: Out-of-sync with VESC, discarding 8 bytes. [ros2_control_node-1] [ERROR] [1693755709.203127802] [VescHwInterface]: Invalid end-of-frame character [ros2_control_node-1] [ERROR] [1693755709.203179020] [VescHwInterface]: Out-of-sync with VESC, unknown data leading valid frame. Discarding 1 bytes.

I tried using the controllers (joint_state_broadcaster and velocity_controller), which worked with a single VESC, launching it with two VESCs with two ros2_control tags including two separate actuator-type hardware. I also tried to change the velocity controller to diff_drive_controller and tried the same thing with two VESCs. But it fails every time. I am attaching the screenshot of my configuration and xacro file. Any suggestion will be really helpful.

[NB. I commented out the servo parameters and used parameters that are required for velocity as command interface and positional and velocity for state interfaces]

[sidtalia]

Hi, Apologies for the late response, we do not currently support ROS2. However, as a hunch, the two vescs have different port names. If you execute

ls /dev/ttyACM*

you should probably see

/dev/ttyACM0
/dev/ttyACM1

You would then need to specify the port name for each vesc (usually given in the launch file).

Thanks,
Regards,
Sidharth.