Observer-Based Control Design for DC Servo Motors: Pole Placement and State Estimation for Enhanced Time Response and Stability Margins

Abstract

Nowadays, both state and frequency methods have their places in the control engineer's design kit. In most cases, the frequency domain is a better way to define specifications. On the other hand, it appears that the state methods are suited to numeric work. This paper shows the linkages between the two. Pole placement requires that the whole state vector be available, a condition that is often not met in practice. This paper proposes a dynamic system called an observer to generate estimates of the states. Observer-based control has been applied to the control of a DC servo motor, where the estimates of angular position, the angular velocity and the armature current are used to generate the control signal. In this paper, we studied a design method that is fundamentally different from the classical methods. In state feedback, the controls are generated as a linear combination of the state variables. Observer-based controller has been successfully used to control a DC servo motor. The controller poles are selected to give good time response specifications and good stability margins.