Decoupling research on a car suspension using principal coordinate of oscillation equations

Under research on principal coordinate of oscillation equations of multiple-degree-of-freedoms, if the relation between sprung mass of a whole car suspension and four sprung masses supported by four wheel systems is determined, the mass distribution coefficient in automotive theory would be enriched. In this paper, based on vertical and lateral excitations under the wheels, a traditional car model with fifteen degree of freedoms is adopted as research background. With the help of force analysis of sprung mass in space and investigations on vertical, lateral, pitch angle, roll angle and yaw angle motions, the principal coordinate equations of a whole car from vertical and lateral sides are obtained. The ratio relations of coupling dynamics between a whole suspension and four quarter suspensions are deduced and achieved. The results obtained in this paper found the theoretical basis for future studies on vibration control of suspension system, steering and running stability in vehicle field.