Robust State Control


State control of modern control theory can achieve very high dynamics. It allows versatile tuning, either by defining desired locations for each pole of the plant (pole placement) or by applying one of several optimization criteria to the control response (e.g. LQR, H-infinity). However, without additional servo compensators or disturbance observers, state control does not guarantee zero steady-state error. Moreover, servo compensators increase robustness with respect to deviating plant parameters significantly. We have applied state control with servo compensators for dc applications as well as ac applications and have achieved excellent results.