Optimizing Kinematic Performance of Multi-Link Suspension for Rear Wheel Steering Implementation: A Suspension Level Development

The introduction of Rear Wheel Steering (RWS) to the existing multi-link suspension system requires careful analysis of kinematics & elasto-kinematics characteristics in order to deliver optimal vehicle dynamics performance. Since the existing multi-link suspension system is not optimized for the use of a steerable wheel, the introduction of RWS requires considerable hard point changes & geometric modifications in order to deliver optimal steerability performance. Steering parameters like kingpin inclination (KPI), caster orientation, scrub radius, caster trail, and lateral and longitudinal offsets of the KPI axis to the wheel center and tire contact patch become deciding parameters that must be given due consideration to ensure the desired steering dynamics. This research aims to identify principal vehicle dynamics K&C parameters important to the effective application of RWS without sacrificing handling and stability of the vehicle. The challenge is to compromise rear axle articulation with prevailing suspension geometry and packaging needs, especially for Sport Utility Vehicle (SUV) platforms with severe packaging conditions. Simulation-based design process with Adams software is utilized to iteratively tune suspension parameters while maintaining fundamental vehicle dynamics attributes. The overall research proposes a step-by-step methodology for the evaluation and optimization of suspension-level performance parameters that have influence on the vehicle dynamics characteristics of the vehicle, ultimately resulting in the synthesis of an efficient, dynamically robust, and packaging-conformant multi-link suspension system with rear wheel steering unit. The conclusions are highly valuable as feedback on vehicle dynamics adaptation techniques for advanced chassis systems with rear axle steering.