I am working on a dyamic control of a mobile robot. I have developed a nonlinear dynamic model. What I am not sure is how accurate the dynamic model is needed in order to have a stable optimal control output?
If the robot is stable by itself, set all your gains to zero.
If you want more than just a stable robot you may need to use more information than what you've shared with us.
I've got a pretty jaundiced view of "optimal control". It works great, as long as you jigger the process by putting a cost on the control variables. This is almost never done because the control variables are expensive -- it's done to fake the algorithm into making a 'safer' controller, and the margins are hard to figure out.
I suggest you try the high-control-variable-cost approach, but go back and check your system for stability as you vary the parameters of of your plant. If you want to do this in a formal manner, study up on robust control.
Thanks for your suggestions. Yes, I have picked a control cost and control variable and obtained a two point boundary value problem, which is solved by using relaxtion method. The process requires iteration. But it is not too bad for a P3 machine. What is the high-control-variable-cost approach? I have not studied robust control. What is the main difference between optimal control and robust control? Can you tell me the pros and cons of the two methods?
Thanks a lot and have a nice weekend,
Everett ps. You have given me quite a few suggestions already on the selection of brushless vs. step motor, optimal control etc before. Thanks a lot.