Simplified MIMO design of observer-based PI control in view of input saturation

Abstract In observer-based control integral or controller windup can systematically be prevented by the observer technique, i.e., by feeding the saturated plant input signal into the observer. This prevents all windup effects caused by the dynamics of the compensator. The possibly remaining windup effects are then the same as if constant state feedback control had been applied. When using the classic approach for robust rejection of persistent disturbances the state-plus-disturbance observer is subdivided into the state observer and the controlled signal model. Thus the observer technique is only applicable when taking additional measures or when resorting to a recently published dual design method. Here, a very simple design for MIMO PI compensators is suggested which directly yields the basis for the observer technique.