mpExRcsIncrementMove concerns

[mooonick]

i wonder to know when a increment value has been excuted completely and how to control the servo speed when using mpExRcsIncrementMove API. Because i have modified the motoman_driver to execute offline dense trajectory points other than online interplotaion by cubic polynomials algrithm. But I don't understand the mechanism of increment move. Can anyone help? Thanks a lot.

[ted-miller]

mpExRcsIncrementMove is supposed to be called at the rate of the robot's interpolation-clock. Generally, this is 4ms. The exact period can be obtained at runtime with GP_getInterpolationPeriod.

For each call of the IncrementMove function, you are commanding the amount of pulse counts (encoder increments) that each joint should move in that 4 ms window. So if you want to command a high speed, then you would provide larger increments.

[mooonick]

Thanks for your comments! Actually I find that the last increments is not running out in 4ms. If new increments is injected in by mpExRcsIncrementMove in every 4ms, increments will be accumalated one by one and you can not get a expected execute time of a whole trajectory.

[ted-miller]

There is a latency that occurs between calling mpExRcsIncrementMove and the robot's physical motion. Additionally, the robot controller does perform some filtering/smoothing of the data submitted to the motion API. #458 has a decent discussion on the topic. Plus, it shows a method to help improve upon the responsiveness of the motion.

[mooonick]

I have scrutinized the discussion, the HTRAJ functions with a new INIT_ROS seems like an elegant solution. I would like take a try. Thanks again for your quick response, if there is any progress, i will share it here.