[stevendhansen]

Just because controllers have proportional and integral terms does not mean they are PID controllers!

I'm not just being pedantic here, there is a world of difference between a modern servo controller and a simple (or advanced) PID controller. Good servo controllers include completely different topologies including state feedback decoupling, disturbance decoupling, state tracking feedforward terms, advanced notch filters, sliding mode gains, and many other techniques. This is not just an advanced PID loop, but a different controller design method altogether.

Source: I design servo (and other motor) controllers for a living