Design of PID Controllers Using Genetic Algorithms Approach for Low Damping, Slow Response Plants

Proportional-Integral-Derivative (PID) controllers are widely used in process control industry for years. Those plants are in general, slow-response with moderate or low damping characteristics. Zeigler-Nichols(ZN) tuning methods are some of design approaches for finding PID controllers. Basilio and Matos(BM) pointed out a systematic way to design PID to meet transient performance specifications. As for the low-damping, slow-response plants, the BM approach also failed to find the controller. We suggest two approaches to overcome this afore-mentioned difficulty. These two approaches are approach of using approximate 2nd order zeros to cancel the embedded plant poles, and GA-based fine-tuning approach.