A Self-tuning Hybrid Fuzzy-PID Controller for first order Hydraulic systems

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 K-p, K-i and K-d during system operation, with respect to the reference signal eliminating the need to manually readjust the Proportional, Integral and Derivative gains (K-p, K-i, K-d) for each control signal. Modeling and initial analysis have been done in MATLAB-Simulink which shows excellent characteristics compared to classical PID Control.