A FORCE-BASED SUSPENSION MODELING APPROACH FOR VEHICLE STEADY-STATE HANDLING

This paper presents a modelling procedure for predicting steady-state cornering behaviour of four-wheeled vehicles. The method retains the s implicity and insightfulness of the traditional Kinematic Roll Centre approach, but requires less input data than multi-body simulations usi ng commercial computer programs. The core concept of the method is to model the suspension at each wheel with its equivalent swing-arm by id entifying the instant centre between each wheel and the chassis. Then, tyre contact patch forces can be decomposed into two force components , one normal to this swing arm which causes suspension deflection, and the other along the swing arm which transfers directly to the chassis . Using these force components, true chassis positions can be resolved , and accurate tyre forces predicted. The key advantages of this appro ach are (1) the contribution of lateral loads to chassis heave is incl uded, (2) a more accurate load transfer prediction results, (3) higher -order tyre effects, such as camber thrust, can be included, and (4) a ccurate predictions are possible at high levels of lateral acceleratio n. Significant insight into suspension behaviour also results from stu dies using this approach. The method presented in this paper is compar ed with the traditional Kinematic Roll Centre approach, and the effect s of suspension design on chassis roll and heave are discussed.