INTELLIGENT CONTROL OF ACTIVE SUSPENSION FOR 2 DOF AND 3 DOF QUARTER CAR MODEL

Abstract

Suspension system plays most significant role in supporting the vehicle weight and isolating vehicle body from road shocks and vibrations. The aim of suspension system is to suppress uncomforting situations from road unevenness to driver and passengers and to provide road handling and stability of vehicles. The aim of this research work is to design different types of active controller for active suspension system. By using mathematical modelling 2 DOF and 3 DOF quarter car model are designed. The objective is to determine a control strategy to achieve better road quality and ride comfort by delivering better performance with respect to seat acceleration, seat displacement, suspension deflection, sprung mass displacement, tire deflection in terms of peak overshoot, settling time etc. Four different active controllers are designed using 2 DOF quarter car model as well as 3 DOF quarter car model to compare the performance of Four controllers with the passive suspension system. The Four controllers designed are PID, Fuzzy logic controller ,Fuzzy PID controller and Linear Quadratic Controller (LQR). Three different road profiles such as Step, Sine and Band limited white noise are taken as input disturbances. In this work, MATLAB/SIMULINK software is used for simulation purpose and simulation result demonstrate that active suspension system shows better results in comparison to passive suspension system with reference to body acceleration, suspension deflection, tire deflection. Also the result of comparison shows that Fuzzy PID controller based active suspension system gives better result and stability as compared to other active controllers and passive model.