Masoud Khaksar Toroghi - Dept. of Chem. & Petroleum Eng., Sharif University of Technology, Tehran, I. R. Iran
Mohammad Ali Fanaei - Dept. of Chem. Eng., Faculty of Eng., Ferdowsi University of Mashhad, Mashhad, I. R. Iran
Mohammad Shahroki - Dept. of Chem. & Petroleum Eng., Sharif University of Technology, Tehran, I. R. Iran

In this paper, a fuzzy self tuning PID controller for unstable continuous stirred tank reactor is proposed. The essential idea is the on-line controller's gain tuning based on the error pattern (difference of controlled variable and its set point) and fuzzy rules. The performance of the proposed controller is compared with conventional PID. Simulation results show that when the gain of nonlinear process has a big change, proposed controller has better performances than PID controller.

Fuzzy self-tuning PID, PID control, unstable CSTR reactor