Abstract
Rollover is a serious vehicle safety problem, which can result in large financial and environmental consequences over the world. In order to improve roll stability most of modern vehicles are equipped with anti-roll bars to reduce roll motion of the car body during cornering or riding on uneven roads. This paper introduces the formulation of the forces generated by the anti-roll bars as functions of the anti-roll stiffness and the relative displacement between the car body and the left and the right wheels. A four-degree-of-freedom half car roll model that captures the essential vehicle dynamics associated with rollover phenomenon is represented. Numerical simulations are performed to demonstrate the contribution of roll stiffness to rollover stability and show the conflict between ride safety and ride comfort of the vehicle. This conflict is solved based on the multi-criterion optimization (MCO) approaches where both ride safety and ride comfort are considered as the objectives need to be optimized at the same time. The task of MCO problems is to find the so-called Pareto frontier or trade-off curve containing all of the Edgeworth-Pareto (EP) optimal solutions. An effective scalarization approach for obtaining a sample set of points of the Pareto frontier, called compromise method, is introduced and applied to define the optimal suspension parameters with respect to the best trade-off between ride comfort and ride safety. The obtained results show the significant effectiveness of the optimized suspension on both ride safety and ride comfort of the vehicle.
Keywords: anti-roll bar, rollover, vehicle roll model, ride comfort, ride safety, multi-criterion optimization.