A New Design of Feedfoward Control for Non Minimum-Phase Systems Based on the Extended Inverse Function

Abstract

In principle feedback control can not change the non minimum-phase characteristics with undershooting phenomenon. An extended inverse function is introduced to realize the stable input-output dynamic inversion of all-pass functions involved in non minimum-phase characteristics. Responses of the non minimum-phase systems can be improved by the combination of the feedforward based on the extended inverse function and the feedback from the minimum-phase state of the object. Numerical example reveals that the feedforward control suppresses the undershooting phenomenon acconmpanied by the responses.