Tremor durring trajectory execution

[leo1614]

I use your driver to operate the robot. I copied Karel programs by installation script and use streamer to send points to the robot.
As you can see in this video robot has a tremor during trajectory execution. Did you faced this situation?

[gavanderhoorn]

What the video shows seems to be stop-and-go motion, not necessarily a tremor (but I understand why you describe it that way).

Unfortunately, for (relatively) dense trajectories, this is currently expected behaviour.

See Fanuc robot slows down at each trajectory point despite CNT is set to 100 for a discussion of the behaviour you're seeing specifically, and see Motion performance between fanuc_driver/fanuc_driver_exp vs offline trajectory generation (and the linked Q&As and issues there) for instance for a previous discussion about the general problem.

Other examples of similar discussion: How to make Fanuc CRX-10iA/L move faster?

[gavanderhoorn]

Note: personally, I believe this will always happen when using Fanuc robots in this way. At least when using a Karel+TP program to control them via a network socket. Either the controller can use look-ahead and smooth out your trajectory to maintain motion continuity, or it doesn't smooth anything and you get stop-and-go motion.

This is what you can control in a TP program using the CNT modifier.

fanuc_driver_exp doesn't allow the controller to use its look-ahead, so the stop-and-go is even more pronounced, but it's a fundamental 'limitation' I believe due to how (ind) robot controllers work (even Fanuc's own RMI would exhibit the same thing if you don't have CNT set high enough).

Something like J519 would allow you to control motion very accurately, but getting that to work reliably is far from easy.