PIR controller design using optimization based on integral performance criteria

Nowadays, automatic control systems are widely used to stabilize industrial processes and achieve desired system responses. Proportional-Integral-Derivative (PID) controllers are one of the most preferred structures and improve system performance using its three basic components. However, the negative effect of the derivative term on system stability has brought alternative controller structures to the agenda. Proportional-Integral-Retarded (PIR) controllers, one of these structures, aim to produce more stable and balanced system responses by using a time-delayed component instead of the derivative term. In this thesis, firstly, the classical PID controller structure is examined and Ziegler-Nichols methods used in PID controller design are investigated. Using the Ziegler-Nichols PID controller design method, designs are made for different systems. Then PIR controllers, which are the research topic of this thesis, are introduced. A method based on integral performance criteria is presented for the design of the PIR controller. The integral performance criteria used are ISE (Integral Squared Error), IAE (Integral Absolute Error), ITSE (Integral Time-weighted Squared Error) and ITAE (Integral Time-weighted Absolute Error). For the PID, the structure K_p+K_i/s+K_d s is used. The PIR controller is modeled as K_p+K_i/s-K_r e^(-sh). The optimization method presented in this thesis is used to calculate the parameters K_p,K_i, K_r and h of the PIR controller. PID and PIR controllers are designed for different systems and their unit step responses are analyzed and their performance are compared by looking at response parameters such as overshoot rate, rise time, settling time. It is shown that the PIR controllers designed by optimization method provide good performance.