[Tom Bottiglieri]

kTurn was the P gain for a controller which tried to keep the robot's heading (measured by a gyro) on course with where it currently was in a pre computed 2d trajectory. I'd tune this by writing some code that tries to get your robot to turn 45 degrees in place and picking a gain that gets close the robot to the target with minimal overshoot. If you run the full controller and bot starts to wander off course and can't make harder turns, increase the gain. If you see oscillation, decrease the gain. If your drivetrain is relatively well balanced efficiency wise, you just need to be in the right ballpark.

Do you need 2d trajectories for your task?