STUDYING THE EFFICACY OF ROAD DISTURBANCE AMPLITUDE AND SPEED INCREASING ON PERFORMANCE OF SEMI ACTIVE SUSPENSION SYSTEM

In this paper the performance of designed semi active suspension for a passenger car has been investigated under different road condition and different vehicle speeds. Semi active suspension is an appropriate scheme for vibration control in vehicles due to its high performance, which is close to active suspensions. However semi active suspension has less cost and energy usage than active suspension. Two most significant parameters in designing process of each suspension system are ride quality and handling parameters of the vehicle, which have been used for studying the performance of suspension system. Transferred chassis acceleration to the passenger has been assumed as a ride quality and tire deflection has been assumed as handling of vehicle. Parameters of the Renault Megane Coupe have been used for modelling and simulation of a vehicle moving at speeds of 80, 108 and 130 [Km/hr] in a rough road with disturbance amplitudes of 0.02, 0.05 and 0.08 [m]. For investigating the performance of semi active suspension system a quarter car model with two degrees of freedom has been used. Performance of the semi active suspension system has been investigated in the range of damping coefficients from 1000 to 6000 [N.s/m]. The obtained results show that by increasing the vehicle speed and road disturbance amplitude, transferred acceleration to the passenger and tire deflection will be increased. This means that ride quality and handling of the vehicle have been decreased. Also the range of 1000-2000 [N.s/m] for damping coefficient and disturbance amplitude domain from 0-0.06 [m] is the most appropriate amount due to its low rate of sprung mass acceleration and tire deflection.