On the design and testing of a smart car damper based on electro-rheologicaltechnology

Abstract

This paper presents the different steps involved in designing, building and testing anintelligent damper, which is originally a classic passive damper retrofitted withelectro-rheological (ER) technology, that can be used for semi-active car suspensions.Following an overview of the essential features of ER fluids, this paper examines thedifferent design details required in building an efficient ER car damper. This particularmodel, filled with a ‘Rheobay VP AI3565’ ER fluid, was experimentally testedfor different speeds and under different electric fields. The experimental resultsobtained clearly show that, when the high electric field is turned on, the generateddissipative force, and hence the damping characteristics, could be greatly increased.The dynamics of this first ER damper prototype model were numerically analysed, with anemphasis placed on evaluation of the influence of the electrical field on the resultingdynamic response. The results show that the damping ability could be easily increased byincreasing the height of the moving electrode. However, this damping increase, whichincreases the stiffness of the ER damper, should be handled carefully by both the designerand the user. Indeed, there is always an optimal damping value which provides acompromise between car stability and ride comfort. Moreover, the simulation shows thatthe controller used to control the damper should not only apply an on/off policybut should also be able to deliver a variable value of the applied high voltage.