Methodology to Determine Optimum Suspension Hard Points at Early Design Stage for Achieving Steering Returnability in any Vehicle 2019-26-0074
Steering returnability while driving is one of the most important parameter which affects the drive pleasure and handling of a vehicle. Steering returnability refers to the automatic returning response of the steering wheel after taking a full turn while vehicle is being steered during driving. Evaluating steering response characteristics of any vehicle in a virtual environment at early stage of a product development saves significant development time and cost. Through this paper an attempt has been made to develop a methodology for selection of suspension hard points which influences steering returnability characteristics for any vehicle at early product design stage. Conventionally, standard suspension kinematic parameters such as caster angle, king pin inclination (KPI), etc. are selected during suspension design stage to achieve desired steering returnability. However, at times vehicle level trials indicate that increasing caster angle or KPI does not guarantee a desirable increase in steering returnability. In this new methodology a set of iterative trials are done to vary hard points of lower ball joint of an independent front suspension (X, Y, Z co-ordinates) to create desired jacking effect or differential lifting at front wheel end of the vehicle during steer condition to facilitate and impart self-returning motion at steering wheel. Vehicle level test results conducted on a vehicle indicates an improvement in steering returnability by around 50% with reference to the base vehicle in which hard point modifications were incorporated to validate this methodology. Same methodology can be applied to other vehicles during their early design stage for faster and first time right approach.