Optimization of automatic controller design coefficients

Abstract

Classical tuning methods of PID controller, such as the Ziegler-Nichols and Cohen-Coon tuning formulae are able to tune the mentioned controller easily, when they use for controlling the linear system. But, empirical studies have found that these conventional tuning methods result in an unsatisfactory control performance when they are used for processes experiencing the negative destabilizing effects of strong nonlinearities. It is for this reason that control practitioners often prefer to tune most nonlinear systems using trial and error tuning, or intuitive tuning. A need therefore exists for the development of a suitable tuning technique that is applicable for a wide range of control loops that do not respond satisfactorily to conventional tuning. Particle swarm which is developed by Eberhart and Kennedy (1995), have been utilized to solve many non-linear engineering problems. The Particle Swarm Optimization is the method which is implemented to tune the PID controller to control the exhaust temperature of gas turbine, model M5001. The result is compared to the conventional PID controller using Ziegler-Nichols method. Mathematical model of the exhaust temperature of mentioned gas turbine was extracted from simplified mathematical model which is developed by W.I.Rowen (1983). As it will be discussed in conclusion, simulation result illustrate that using PSO, to tune the PID controller improves the important parameters of the system such as, maximum overshoot, rise time and settling time and reduces the error rather than conventional tuning method such as Ziegler-Nichols technique.