DYNAMIC MODELING AND CONTROL OF SEMI-ACTIVE SUSPENSION SYSTEM FOR ROAD VEHICLE

Abstract

The vehicle suspension system is generally considered as the linkage between the vehicle body and wheels. The main task of the suspension system is to provide a comfortable and safe ride. The good ride quality requires high damping setting at low frequencies to suppress pitch, and lower damping setting at higher frequencies to prevent harshness. However, to improve handling performance, springs and dampers must be made stiffer at all frequencies to reduce body attitude. The design of a better-quality suspension system remains an important development objective for the automotive industry. An ideal vehicle suspension should have the capability to reduce the displacement and acceleration of the vehicle body, and thus; maximizing the ride comfort. Present work analyzes the dynamic behavior of a road vehicle through bond graph and MATLAB/Simulink®, where vertical and longitudinal dynamics have been evaluated. A two degrees of freedom quarter car model and a four degrees of freedom half car model have been considered for the performance assessment. Simulations have been carried out on SYMBOLS Sonata® and MATLAB® software environments. The results obtained are used to evaluate the performance of the system. The work also includes different types of suspension systems such as passive and semi-active suspension system, where physical and mathematical models of quarter car and half car have been evaluated. Different semi-active suspension control algorithms have been incorporated to the system models to optimize the efficiency of the vehicle for bump type and random road inputs.