Parameter estimation method for the unstable time delay process

Abstract

The paper considers the evaluation of all the three parameters of the unstable first order process with time delay by using the process data received from the closed loop step response under proportional control. The new method of analysis of parameters identification is presented. One is required to read five parameters from the closed loop step response for the purpose of applying the method. For the selected proportional controller gain and the received process gain, the time constant and time delay of the unstable first-order plus time delay model is received by solving a characteristic system equation using the features of the Lambert W function. The suggested way of parameter estimation is simple and it yields better results than the well-documented methods in literature which the present method is compared with. Simulation results are given for linear system and a nonlinear bioreactor system.