Active vibration control of an automotive suspension system using PID controller

Abstract

The suspension system is an important and the integral part of an automotive system. The purpose of suspension system is not just limited to supporting the weight of the vehicle body but also to improve the safety, ride quality and comfort by minimizing the effect of vibrations that gets transferred through it by the uneven road surface. When the vehicle is operating in a rough terrain the suspension system must not create large oscillations to prevent the vibrations to get transferred to the car body and it does then it must be eliminated as quickly as possible. Apart from safety and comfort, the vehicle handling is a major responsibility, without suspension system it would be difficult for the operator to control the vehicle since all the vibrations and shock gets transmitted to cabin without any damping. Hence the automotive suspension system has gained a lot of research interest in couple decades and it is still an area of interest in automotive industry due to the recent advancement in the industry and in the field of modelling and simulation. Recent automotive suspension employs the passive type components that uses spring and damper with fixed design parameters only. Due to this limitation, it creates a conflict between two important aspects of good suspension system that is ride comfort and ride handling. Hence there exists a need to develop a system that can eliminate this constraint of passive suspension system. which is an open loop system. The main objective this thesis work is to develop a closed loop feedback mechanism by implementing a controller-based suspension system. A computer-based modelling and simulation software is utilized to build and implement a PID controller in a passive suspension system to improve its overall performance. A quarter car suspension model will be built in a MATLAB Simulink toolbox and a road hump as standard road disturbance will be used to simulate the model. The simulation results will determine the performance parameters of the system such as sprung mass and unsprung mass displacement and acceleration, overshoot and settling time etc. With this results a conclusion can be established between the passive and PID controlled system which offers the better overall performance it terms of ride comfort, road holding and ride handling capabilities.