New Jacobian approach to the kinestatic analysis of a planar double-wishbone suspension mechanism

An understanding of the kinestatic relation between a suspension mechanism and a vehicle body is important for the design of a vehicle with the desired motion characteristics. In particular, when the mechanism has elastic springs, it is necessary to analyse the instantaneous kinematic and statics (or, briefly, kinestatics) relations simultaneously. This paper presents a new Jacobian approach to the kinestatic analysis of a planar half-vehicle model with double-wishbone suspension mechanisms. Introducing the reciprocal Jacobian method of a planar mechanism, the kinestatic relations of a quarter-vehicle model are first derived. Next two instantaneous rotation centres of a pair of quarter-vehicle models are determined and modelled as virtual joints to form a new parallel-type mechanism of a half-vehicle model. Finally, the Jacobian and reciprocal Jacobian of the parallel-type mechanism are found in order to complete the kinestatic relations of a half-vehicle model. Using an illustrated example, it is shown that this new kinestatic analysis can be utilized for determination of the best locations of the strut springs for the least rolling motion due to cornering of a vehicle.