Optimal tuning of PID controller for coupled tank liquid level control system using particle swarm optimization

Abstract

In this paper, particle swarm optimization (PSO) algorithm is presented for determining the optimal gains for a proportional-integral-derivative (PID) controller; which is implemented on a coupled tank control system to maintain the liquid level. Coupled tank system is a non-linear system and finds a wide application in industrial systems; and the quality of control directly affects the quality of uniform products, safety and cost. Initially, Ziegler-Nichols method has been used for the PID tuning but the method does not work perfectly due to lack of precision, long run time and lack of stability. The simulation results indicate that better performance has been obtained for the PSO tuned PID controller as compared with those obtained from GA & ZN tuned controllers. As per the results obtained in the paper, the proposed method is more effective in improving the time domain characteristics such as rise time, settling time, maximum overshoot and steady state error.