PID controller cannot converge to zero.

[jc-bao]

Basic PID

The drone hovers at the point close to the origin.

Perturbating when the stuck

After adding disturbance to the controller: (change the angle if the force is vertical to the displacement to the center)

Observed oscillation.

What about always headed to the target angle?

[jc-bao]

Problem allocated: the first-order decay function included the disturbance force, which result in a constant shift of force.

After moving the disturbance out of the delay, the PID controller works well now.