Comprehensive prediction method of road friction for vehicle dynamics control

Abstract

The contact friction characteristic between a tyre and the road is a key factor that dominates the dynamics performance of a vehicle under critical conditions. Vehicle dynamics control systems, such as anti-lock braking systems, traction control systems, and electronic stability control systems (e.g. Elektronisches Stabilitäts Programm (ESP)), need an accurate road friction coefficient to adjust the control mode. No time delay in the estimation of road friction should be allowed, thereby avoiding the disappearance of the optimal control point. A comprehensive method to predict the road friction is suggested on the basis of the sensor fusion method, which is suitable for variations in the vehicle dynamics characteristics and the control modes. The multi-sensor signal fusion method is used to predict the road friction coefficient for a steering manoeuvre without braking; if active braking is involved, simplified models of the braking pressure and tyre force are adopted to predict the road friction coefficient and, when high-intensity braking is being considered, the neural network based on the optimal distribution method of the decay power is applied to predict the road friction coefficient. The method is validated through a ground test under complicated manoeuvre conditions. It was verified that the comprehensive method predicts the road friction coefficient promptly and accurately.

Evaluation of Safety in Horizontal Curves of Roads Using a Multi-Body Dynamic Simulation Process

“…After examining the outputs of the designed tires, namely pac2002-235-40R18 and pac2002-255-40R19 tires, f xmax and f ymax were obtained as shown in Table 6 . The values obtained are inserted in the friction ellipse formula [ 30 ].…”

A physical-analytical model for a real-time local grip estimation of tyre rubber in sliding contact with road asperities

“…The tests, which are characterized by high computational loads, confirmed the accuracy of the stress fields calculated much more easily with the Kuznetsov-Gorokhovsky equations, which, once implemented, represent an optimal solution for the needs of a real-time physical model. Moreover, information from finite element analysis allowed us to neglect the stress components t xy , t xz and t yz , because their contribution to power dissipation is about one order of magnitude lower than that relative to the components s. Finally, indentation tests confirmed the contact zone extension provided by the work Knowledge of the described stress components allows us to calculate the numerical integral extended to the elementary tread volume of equation (20). With this aim, the volume was discretized in 200 nodes along x and y and in 50 nodes along z; this number represents an optimal trade-off between the stability of the results and the computational performances.…”

Adaptive Unified Monitoring System Design for Tire-Road Information

“…When the vehicle is under steering, the nonlinear extent of the yaw rate u and a y can be used to obtain the error of the friction which may compensate the detected lateral acceleration to estimate the road friction under steering conditions. The nonlinear extent of a y reflects the understeer condition and the nonlinear extent of u reflects the oversteer conditions [29]. Therefore, the comprehensive friction estimation method in Ref.…”