Patent ID: 8200347

Claim:
A controller for controlling a system, comprising: a feedforward module to produce a feedforward component az r , where a is a high frequency gain; a proportional module to produce a proportional component K pv z, where K pv is a proportional gain; an integral or lag module to produce respective integral or lag components, wherein the feedforward module and the proportional module and the integral or lag module form a controller having a state, and the integral or lag module is capable of resetting the state; and means for combining the feedforward component az r , the proportional component K pv z, and the integral or lag components to produce an input u for the system to be controlled, wherein the feedforward module is provided with a reference signal r and an error signal e, and wherein where the error signal is a difference between the reference signal and an output y of the system, and the error signal is also provided to the proportional module.