Changing kv and kp for CMC

[Mark Gordon]

I'm getting different answers when I change the values of kv and kp. Does that make sense?

If so, does that mean I have to leave them at their kind of default values in order to obtain accurate results for CMC?

If not, what might I be doing wrong?

[Ayman Habib]

Hi Mark,

Selection of kp and kv is not arbitrary. They define the behavior of the error dynamics for each q as a second order linear system. We can write the kp and kv for the desired system behavior in terms of system poles. For a (stable) critically damped system (real negative poles) kp = lambda^2 and kv = -2*lambda for some lambda. Changing lambda affects how the controller works and the values chosen in our setup files are there only because they were "reasonable" and worked best for our setup/data files.

Hope this explains,
-Ayman

[Mark Gordon]

I have been using the correct relationship between kv and kp (that you described using lambda). How do I determine what lambda to use? Do I just choose one that gives what I believe to be reasonable results? Is there a recommended range to stay within?

Thanks,

Mark