Determination of pid control parameters by response surface methodology

Proportional – integral-derivative (PID) controllers are the most used systems in the industrial field and find the most research and application area in control engineering. The control output is generated by the addition of three terms called proportional, integral and derivative. Some experimental methods have been developed to tuning the PID control parameters. These methods are applied to the open-line systems without control, but the parameters determined by these methods may not be effective in nonlinear, variable parameter and unstable systems. In this case, it is necessary to determine the optimal PID control parameters. In the scope of this thesis, liquid level control system which operated in Van Yüzüncü Yıl University, Department of Chemical Engineering was used. Dynamic data for control variable was obtained with step change applied to manipulated variable. The dead time, time constant and gain values were determined with the process reaction curve was prepared using step change effect. The optimum values of the PID control parameters are determined by Response Surface Method (RSM). Kp, τI, τD as independent parameters and ISE and IAE values are chosen as dependent variables (responses). Numerical values of the responses for the runs in the design matrices determined using closed-loop PID controller with liquid level system block diagram which designed in MATLAB/Simulink. Simulations in the proposed list by the trial version of Design Expert 7.0 program were performed in order and the IAE and ISE values calculated after the simulations were processed by processing the results. The models were developed through RSM in terms of related independent variables to describe the ISE and IAE as the two responses. Keywords: PID control, IAE, ISE, liquid level, response surface methodology.