OPTIMAL TUNING OF PID CONTROLLERS FOR SINGLE AND CASCADE CONTROL LOOPS

Design of one parameter tuning of three-mode PID controller was develo ped in this present study. The integral time and the derivative time o f the controller were expressed in terms of the time constant and dead time of the process. Only the proportional gain was observed to be de pendent on the implemented tunable parameter in which the stable regio n could be predetermined by the Routh test. Extension of the concept t owards designing cascade PID controllers was straightforward such that only two parameters for the inner and outer PID controllers required to be tuned, respectively. The optimal tuning correlative formulas of the proportional gain for single and cascade control systems were obta ined by the least square regression method.