Comparison of Ziegler-Nichols and Cohen-Coon Tuning Methods: Implementation to Water Level Control Based MATLAB and Arduino
The purpose of this study is to design a proportional (P), proportional-integral (PI), and integral derivative (PID) controller for the water level control system. The system uses Arduino as a data acquisition running through MATLAB/Simulink. Tuning methods, Zeigler-Nichols (ZN) and Cohen-Coon (CC), are based on a first order plus dead time (FOPDT) model and open-loop tuning, and the results were compared. Due to the fast development of the process industry, the higher accuracy of the system is required. Kalman filter was also applied in this study to compensate for the errors of both water level measurement and the process model. Experimental results are shown for comparison of those tuning methods without Kalman filter and the best controllers of ZN and CC tuning methods is PI controller with Kalman filter. The rise time and settling time of the ZN-PI controller with Kalman filter are 40.3 s and 170 s, respectively. The rise time and settling time of the CC-PI controller are 39.3 s and 43.0 s, respectively. The CC-PI controller with Kalman filter has a better performance with a smaller rise time and settling time. After several tests with different tuning methods, this proves the useful application and the efficiency of Kalman filter.