[apalrd]

What do we use?

Drivetrain: We have integrated P control (implemented like I) for drive velocity. We have some special handling for special cases, to fix annoyances in the 20% of situations where the I controller works worse than a human.

Camera: We have a P controller to position.

Mechanisms: We run a P position controller for our motors, and also have a basic on/off controller for window motor mechanisms on Spikes. Depending on how it handles, we might implement D and/or a gain scheduler.

Autonomous: We run a P controller to distance (on each side) or a P controller to heading, depending on autonomous command. The output of either is fed to the P velocity controller above. We do not use the line sensors at all.

Tuning: We determined the highest speed of the slowest side on the ground in both directions in each gear (a total of 4 tuning constants), since the slower side determines the maximum top speed. We have separate sets of gains for each gear, and there are 3 tuning constants (used by the gain scheduler).

Actually, we have 11 motors on our robot. 10 of them have some sort of feedback control on them (velocity or position), and the last has a state-machine controller but no velocity or position control. We like easy, automated control.