Digital Two-Degree-of-Freedom LQI Servo Systems

Design Method and Its Application to Positioning Control of a Pneumatic Servo Cylinder

Abstract

In this paper, we propose a design method of LQI servo systems under digital control. There are few studies about digital servo systems that treated the state feedback case. In this paper, we study the output feedback case and give the optimal design method of an observer, as well as the state feedback gains. The LQI servo system obtained by this method is a two-degree-of-freedom optimal control system such that the reference tracking characteristics and disturbance rejection characteristics are both optimized with respect to separate quadratic performance indices. We apply the design method to the positioning control of a pneumatic servo cylinder, and demonstrate the effectiveness of the design method through experiments.