An effective modeling approach for roll and heave motions for independent wheel suspension systems

Abstract

Abstract Kinematics of independent wheel suspensions are often described by the concept of roll centers. In this article, this concept is critically examined. To overcome the typical simplifications, an enhanced model for a single axle is presented which is able to describe the roll and heave motion without the need of defining a roll center. The focus is on the so-called jacking forces generated by the suspension geometry and constraints. These jacking forces are modeled using the principle of virtual work and enable the description of the geometric load transfer without assuming an arbitrary roll center. Although this transient model is simple compared to complete vehicle multi-body models, effects such as aerodynamic downforce or effects due to camber angle, specifically camber thrust, on the individual suspension system can be considered accordingly. Consequently, characteristics such as ride height changes can easily be determined. Additionally, unequal lateral tire forces on the left and right side of an axle during cornering, and its resulting jacking forces can be taken into account. The proposed model is compared to an existing model, which considers the kinematics of independent suspension systems, and to the classic roll angle calculation, both found in literature. Finally, a validation against a multi-body simulation shows that the proposed model is able to predict roll and heave motions of independent wheel suspension systems in an efficient and physically plausible manner.