Humble fake controller moveit partially broken

[Tejas-Shastha]

Tested within the dev container by following the instructions here and launching moveit with fake controllers (i.e. not a real robot):

• I was able to get into the dev container, build and launch the fake moveit instance.
• Rviz popper up, I planned to a valid goal, and hit execute.
• The console in VSCode showed positive feedback and eventually execution success after some seconds as expected.
• The MotionPlanning visualization in rviz also showed execution success after some seconds
• But the robot did not actually move. This can be verified by introspecting the robot state visually, tf tree etc..

[BarisYazici]

I am guessing the issue might be that the MoveIt with JTC currently only using effort command interface and that's only changing the effort values in the fake hardware. So the fake hardware's position values are never changing.

This could be potentially solved when we support joint position command interface. Then the JTC can directly command the joint position values to the fake hardware which would make the robot actually move.

[Tejas-Shastha]

I am guessing the issue might be that the MoveIt with JTC currently only using effort command interface and that's only changing the effort values in the fake hardware. So the fake hardware's position values are never changing.

This could be potentially solved when we support joint position command interface. Then the JTC can directly command the joint position values to the fake hardware which would make the robot actually move.

Yes indeed I came to a similar conclusion a few days ago after some brief experimentation as well. As you say, only the position command interface works with the fake controllers for the demo (which also requires adding this into the URDF), and only the effort command interface works with the robot. They are mutually exclusive and cannot both be defined simultaneously. I would imagine an elegant solution probably means propagating the use_fake_hardware flag a bit deeper to switch between these contexts.

[BarisYazici]

Joint position command interface will be supported soon. But until then if you wanna use fake hardware, you could add the position command interface in the URDF file and change the interface in this file https://github.com/frankaemika/franka_ros2/blob/humble/franka_moveit_config/config/panda_ros_controllers.yaml#L21

[SCerq]

Dear BarisYazici,

we are currently facing a similar problem. Could you provide more detail regarding the solution you proposed? specifically, in relation to this part? "you could add the position command interface in the URDF file"

Thank you

[LeonYo153]

Dear Baris Yazici,

I also met this problem, is there any updates? I'm also confused about"you could add the position command interface in the URDF file"

Thank you