Superiority of using interval type-2 fuzzy PID controller over the conventional type-1 fuzzy controller in a chlorine flow control system

A precise flow control of Chlorine in an industrial Chloroacetic acid production line is essentially important for the safety and quality of the production. Due to the time variability properties and non-linear characteristics of the system, an enhanced controller over the conventional PID controller is sought to be utilized for controlling a Chloroacetic acid reaction kettle. In this paper, the performance of an Interval Type-2 Fuzzy-PID (IT2F-PID) controller is assessed and compared with the Type-1 Fuzzy-PID (T1F-PID) and conventional PID controllers for flow control of Chlorine gas in a Chloroacetic acid production process. Specially, the Type-1 and Type-2 Fuzzy systems are employed for online parameter adjustments of the PID controller. The outcomes of MATLAB simulation obtained in this study illustrate that the efficiency of the Interval Type-2 Fuzzy-PID controller is considerably improved compared to the Type-1 Fuzzy-PID controller. In addition, the studied control system shows a faster response using the Type-2 Fuzzy-PID having the minimum Integral Squared Error (ISE) value and Integral Absolute Error (IAE) over the Type-1 Fuzzy-PID and the conventional PID controllers. The IAE is 18.57 for IT2F-PID, which is less than that for PID (24.53) and T1F-PID (19.14) controllers. Similarly, the ISE for IT2F-PID is 13.23 that indicates a better value in comparison with PID (16.7) and T1F-PID (13.34) controller.