A Self-Tuning Hybrid Fuzzy-PID Controller for First Order Hydraulic Systems

Abstract

A Self-Learning Hybrid Fuzzy-PID Controller is developed for pressure control in a first order hydraulic tank system. The system is closed loop wherein a hybrid Fuzzy-PID controller prescribes the duty cycle of a PWM generator which controls an ON-OFF valve connected to a hydraulic tank. The hydraulic tank is modeled as a first order system. Appropriate fuzzy rules and membership functions are developed for inputs such that the self-organizing Fuzzy-PID controller readjusts the initial tuning parameters Kp, Ki and Kd during system operation, with respect to the reference signal eliminating the need to manually readjust the Proportional, Integral and Derivative gains (Kp, Ki, Kd) for each control signal. Modeling and initial analysis have been done in MATLAB-Simulink which shows excellent characteristics compared to classical PID Control.