Autonomous: Mixing Drive Distance PID's with Turn Angle PID's.

[Jared Russell]

The method of adding the two outputs that you propose will work (and work well once the loops are tuned). The limitation of what happens when one drive side is saturated (e.g. can't go any faster) is a problem - as you noted.

The simplest/best strategy for dealing with this problem in my experience is a function which detects this case and adjusts both outputs (left and right) to ensure that the proper ratio between left and right drive power is maintained, while neither output exceeds +/-1. Note that it helps to have a linear response curve before doing this (e.g. use Jaguars, or write a linearization function for your Victors). If you look at the newly-posted 2011 Team 254 code, you will see code to deal with this scenario.