Internal model based PI controller design for the coupled tank system: An experimental study

This paper presents an Internal Model Based (IMC) tuned PI controller for real-time control of a coupled tank liquid level system. The IMC is a model based controller design technique. In present scenario the IMC Controller method is widely used in almost every process control industries as it allows good set point tracking along with sulky disturbance response especially for the process with a small time delay. In the present work the model of the coupled tank system has been developed based on system identification technique that employs least square error algorithm (LS) for parameter estimation. The proposed controller algorithm has been applied on the identified model. The performance of the proposed control algorithm has been compared with that of a Ziegler-Nichols tuned PI controller. From both the simulation as well as the experimental results, it is observed that the performance of the proposed PI control techniques is more efficient than the conventional PI controller which is tuned by Ziegler-Nichols approach.