Effect of center of gravity location on optimum performance of random vibratory vehicle suspension

This study provides the analysis for the optimal design of a conventional vehicle suspension system, consisting of a sprung mass (vehicle body) and two unsprung masses (wheel frame), accentuated by the implementation of a damped absorber to the unsprung masses. Further, the effect of the c.g. (center of gravity) location of the vehicle body is investigated. A two dimensional, four degrees of freedom linear model is chosen. Randomly profiled terrain is assumed to impart hyperbolically distributed stationary vertical random displacements to the front and rear wheels. For generalization, nondimensional design parameters are selected. Criteria for optimization include the tire-terrain normal force as an indication of vehicle controllability and ride safety, vertical acceleration of the sprung mass as a measure of ride comfort, as well as the relative displacement of the suspension components referred to as the rattle space . Optimum parameter synthesis is performed, producing a family of trade-off curves represented in three dimensional space