I'm doing a autonomous robot based on a differential drive design (2 wheels controlled by 2 motors) and we're having difficulty setting up a good PID controller to allow the robot to go straight. I am interested in knowing how to parametrize a tiny DC motor that way I can use a state space approach for the PID controller. Any help will be greatly appreciated.

 

What type of feedback are you using to control the DC motors? If you use
a decent encoder to track error, you should have no problem making the
two motors track position well with a PID controller.

KEJR

 

For tuning each servo axes separately as first step, Application Note from Galil maybe suggested:

www.galilmc.com/support/appnotes/optima/note3413.pdf

But I think you need dual axes controller at least with possibility to perform crossing control between axes.