Design and Analysis of Semi-active Suspension Using Skyhook, Ground Hook and Hybrid Control Models for a Four Wheeler

The three main objectives that a suspension system of an automobile must satisfy are ride comfort, vehicle handling and suspension working space. The aim of this paper is to design and analyze the semi active suspension system models using skyhook, ground hook and hybrid control method. The two degree of freedom (2 DOF) quarter car model is used for analysis of vehicle body displacement, vehicle acceleration and suspension working space and dynamic tire deflection. Simulation of semi active control models are carried out in MATLAB SIMULINK which describes performance of passive system, skyhook on-off and continuous control, ground hook control and hybrid control methods. Time response analysis shows that, for road bump excitation of 70mm vertical displacement, skyhook on-off control improves ride comfort for the results of maximum peak to peak body displacement with 27.53% improvement than that of the passive suspension model. While ground hook control improves vehicle stability for the results of maximum peak to peak wheel displacement and dynamic tire deflection which has improvement of about 7.69% and 23.07% respectively when compared with passive suspension model. Where hybrid control improves ride comfort as well as road stability depending upon the controller gain. The semi-active quarter car simulation is enhanced with 3-D animation of car going on bump created in VRML tool in MATLAB. This study will help in better design and also in improving the ride comfort and vehicle handling performance of a four wheeler.