Physical Interpretation of Transfer Function Zeros for Simple Control Systems With Mechanical Flexibilities

Abstract

Physical interpretation of the transfer function zeros of simple control systems with mechanical flexibilities is presented. It is shown that for discrete spring-mass systems and elastic beams, the poles are the resonant frequencies of the flexible structure and the complex conjugate zeros are the resonant frequencies of a substructure constrained by the sensor and actuator. It is also shown that when the flexible control systems become nonminimum phase, the real zeros are the results of nonpropagation of energy within the substructure.