State Feedback Control and Kalman Filtering with MATLAB/Simulink Tutorials

5Disturbance Rejection and Reference Tracking via Observer Design

5.1 Introduction

Beginning with this chapter, reference signals and disturbance signals are introduced in the discrete‐time state feedback control. For the discrete‐time control system design, the reference and disturbance signals include step signal, ramp signal, sinusoidal signals, or any arbitrary combinations between them. Thus, the discrete‐time design allows the disturbance rejection and reference tracking of complex signals in a multi‐input and multi‐output system and offers a much broader scope in various control system applications than their continuous‐time counterpart.

The objective of this chapter is to introduce disturbance rejection and reference tracking with a disturbance‐ observer‐based approach. The chapter begins with the general discussions on disturbance signals and their characterizations (see Section 5.2). After having been familiar with the commonly used disturbance models, Section 5.3 proposes how to compensate the disturbances in the state estimation. In Section 5.4, a disturbance‐observer‐based state feedback control is introduced. In Section 5.5, the disturbance‐observer‐based control system is analyzed. With this disturbance‐observer‐based approach, an anti‐windup mechanism is naturally introduced for the controller implementation (see Section 5.6). Both MATLAB and Simulink tutorials are given in this chapter for the design and implementation of this state feedback controller.