Modelling and dynamic simulation of braking stability in asymmetry chassis

This paper investigates the braking stability from the viewpoint of dynamic simulation. Braking stability refers to the abilities of the vehicle to keep straight or the controllability combined with steering wheel during braking. Suspension extra steer/toe angle caused by forces and moments could change the actual wheel angle directly as well as the tire slip angle, since there is a relationship between tire slip angle and lateral force, braking stability will be changed by the change of lateral force. The orientation of kingpin axis will change during braking, and Wheel alignment and the Position and Angle of the Kingpin Axis (PAKA) have a heavy influence on braking stability during emergence braking and braking on μ-split road. This paper analyzes the importance parameters of wheel alignment and PAKA in suspension K&C during braking stability for asymmetry chassis, and point out that ride-steer and Fx-toe are the key factors that affect braking stability. Vehicle dynamic model is built to analyze braking stability, which include precise description of suspension K&C characteristics, steering system model that can reflect the self-adaptive steering capacity of left and the right wheels, and non-linear UniTire model. Braking stability has been validated well using this vehicle model on the asymmetry chassis.