Fuzzy PID Controller Design for a Coupled Tank Liquid Level Control System

In industrial processes, the most important loop is the liquid-level control loop. The coupled tank system CT-100 becomes an essential apparatus for process control researchers. This paper introduces two controller techniques to control the water level in the second tank as a single input single output system. The PID controller is designed to control the linearized model, where the controller parameters are tuned using the Ziegler- Nichols tuning method. In addition, Fuzzy PID is designed based on adequate knowledge and experience. The proposed control approaches are simulated using MATLAB Simulink. Then, the obtained results using these controllers are compared in terms of time response specifications and the ITAE criterion. It is also, tested for step-change tracking signal and disturbance rejection. Finally, the simulation results showed that the Fuzzy PID controller has a robust performance.