PID Issue

[Alan Anderson]

Originally Posted by rclothier

The robot is on blocks, so there's no real load on the wheels; shouldn't it work anyway? (We don't want to put it on the ground when it's acting crazy.)

Placing the robot on the floor might surprise you with how well-behaved it becomes. You're trying to tune a velocity PID when the system is essentially unloaded. As you have discovered, such a system is very unstable. There is not enough damping to keep it from immediately overshooting the set point and oscillating wildly.

If you put some load on the wheels, you will get much better results. You could also try to introduce some artificial inertia into the system by limiting the rate of change of the motor commands.