Model Order Reduction and Controller Design of Discrete System Employing Real Coded Genetic Algorithm

Address for Correspondence Maulana Azad National Institute of Technology, Bhopal, Madhya Pradesh, India, Pin: 462051 e-mails: [email protected], [email protected], [email protected] ABSTRACT One of the main objectives of order reduction is to design a controller of lower order which can effectively control the original high order system so that the overall system is of lower order and easy to understand. In this paper, a simple method is presented for controller design of a higher order discrete system. First the original higher order discrete system in reduced to a lower order model. Then a Proportional Integral Derivative (PID) controller is designed for lower order model. An error minimization technique is employed for both order reduction and controller design. For the error minimization purpose, Real-Coded Genetic Algorithm (RCGA) has been employed. RCGA method is based on the minimization of the Integral Squared Error (ISE) between the desired response and actual response pertaining to a unit step input. Finally the designed PID controller is connected to the original higher order discrete system to get the desired specification. The validity of the proposed method is illustrated through a numerical example.