Self-tuning fuzzy PID controller for temperature control in Variable Air Volume air conditioning systems

Abstract

Considering the multi-variable, nonlinearity, time lag and time variation characters of Variable Air Volume (VAV) air conditioning systems, it is difficult for traditional Fuzzy Logic Controller (FLC) or Proportional Integral Derivative (PID) control to get good control performance. In order to overcome the shortcoming of conventional controller, the fuzzy PID composite control method is proposed. This paper builds the mathematical model of the controlled plant and proposes a self-tuning fuzzy PID (SFPID) controller in VAV air conditioning systems, which increases a fuzzy rule base to control the integral parameter of conventional Proportional Integral (PI) controller and applies the modifying factor in controller. Through online adjustment of the integral coefficient and the modifying factor, fuzzy control rule of conventional fuzzy controller is adjusted to improve its function. Simulation is carried to verify the presented theory. Obtained results show that the proposed controller not only is robust, but also gives excellent dynamic and steady-state characteristics compared with traditional controllers.