DESIGN OF REPETITIVE CONTROL FOR REJECTING NONLINEAR MULTIPLE-PERIODIC DISTURBANCES

摘要

Many vibration signals appearing in engineering are nonlinear multi-periodic, i.e., superposition of finitely periodic signals with time varying harmonics. Such signals are dominant in industrial applications, such as machining tool, electrical power generation and transmission, power converters, and engines. Repetitive control has been developed to achieve disturbance rejection for periodic signals. It uses an internal model and achieves improved control by exploiting the periodic nature of the signals. Its applicability has been limited by the requirement of periodicity, and by the computational difficulty in getting a stable closed-loop system. This paper is aimed at overcoming these difficulties and making repetitive control a valuable technique to reject multiple-periodic vibration. Control performance and stability of the proposed repetitive controller with a multi-periodic disturbance are analyzed and its control scheme can be obtained. The decay rate of the error due to the multiple-periodic disturbance inputs is related to the peak value of a defined regeneration spectrum function. The control performance of the presented method is evaluated in an experimental disturbance rejecting control system. Both computer simulation and experimental results are presented to illustrate the effectiveness of the proposed repetitive controller design.