Direct conversion of PID controller to fuzzy controller method for robustness

A new fuzzy control strategy, converted directly from the PID controller, was applied to control the Heating, Ventilating, and Air-Conditioning (HVAC) systems in this paper. It took full advantages of mature technologies of PID parameters tuning to improve the design of fuzzy controllers. The mathematical analytical expression of parameters between fuzzy controllers and linear gains coefficients of conventional PID controllers was got based on the structure analysis of fuzzy controllers. And the fuzzy controller was designed through gains tuning of PID controller based the analytical relations. Because HVAC systems are typical nonlinear time-variable multivariate systems with disturbances and uncertainties, then this new fuzzy controller was applied into temperature control in HVAC systems. The simulation test results compared with the conventional PID control showed that the proposed fuzzy controller is effective and this algorithm has less overshoot, shorter setting time and better robustness etc.