A Self-tuning PID Controller Design based on Fuzzy Logic for Nonlinear Chemical Processes
Yohn García · 2020
A fuzzy self-tuning Proportional-Integral-Derivative (PID) controller, the f-SmartPID, was designed to promote high quality and stable control, and to save time and energy by ensuring continuity in nonlinear chemical processes. Because PID controllers were developed using linear structures, its performance is severely affected when working with nonlinearities of the process. A PID fuzzy filter was designed to deal with nonlinearities. Two fuzzy inference systems were incorporated to the conventional PID controller to modify the closed loop time constant when required, originating a fuzzy closed loop time constant. f-SmartPID updates the controller gain to avoid undesirable oscillations and maintain stability in the control loop under extreme conditions. This controller was tested in a highly nonlinear process facing disturbances and set point changes, showing optimal performance in linear and nonlinear conditions. It was compared with the Conventional PID controller and the IMC (Internal Model Controller).