Glycerin bleaching process response using fuzzy PI plus PID controller / Rshad Affandi

This paper was aimed to develop and implement a Fuzzy PI+PID Controller for a glycerin bleaching process. A proportional–integral–derivative controller (PID controller) is a generic control loop feedback mechanism (controller) widely used in industrial control systems – a PID is the most commonly used feedback controller. A PID controller calculates an "error" value as the difference between a measured process variable and a desired setpoint. The controller attempts to minimize the error by adjusting the process control inputs. Fuzzy controllers are very simple conceptually. They consist of an input stage, a processing stage, and an output stage. The input stage maps sensor or other inputs, such as switches, thumbwheels, and so on, to the appropriate membership functions and truth values. The processing stage invokes each appropriate rule and generates a result for each, then combines the results of the rules. Finally, the output stage converts the combined result back into a specific control output value. In this study, the ideal PID control structure was tuned by using Ziegler Nichols tuning method and Integral of Time and Absolute Error (ITAE) method. The performance of the system was evaluated in terms of settling time (Ts), rise time (Tr) and percentage overshoot. Apart from that, the performance for different membership function was also compared. The results revealed that Fuzzy PI+PID controller method improve the glycerin bleaching process performance.