A Method of Output Feedback Adaptive Nonstationary Control (Its Application to Positioning Control of Vibration Systems)

Abstract

One of the authors has proposed an adaptive nonstationary control (ANSC) method and its applications to positioning control of vibration systems. In that control method, the time-varying feedback gains are obtained by online computations of a time-varying Riccati equation taking the parameter variations of the controlled object into account. However, the previous paper discussed as the state feedback control method. Its improvement to the output feedback control method is one of important issues for actual applications. Generally, the output feedback controller of the optimal control includes Kalman filter as the observer. However, the use of Kalman filter for the ANSC method requires much computational load in actual implementations because it is designed by another time-varying Riccati equation. Therefore, this paper proposes a practical output feedback control method of ANSC without Kalman filter. The proposed method corresponds to a two-degree-of-freedom control system which consists of an online simulator and a sliding mode controller. This structure enables us to reduce the computational load. The effectiveness of the method is verified theoretically and experimentally.