The Research Of Brake Performance Evaluation For Vehicle Equipped With ABS

In the initial development stage of automotive products, implementation performance evaluation for automobile equipped with chassis electronic control system, such as ABS, based on the vehicle dynamics model and chassis electric control system virtual prototype. On the one hand it makes vehicle manufacturers, in product design stage, can bring forward requirements to automotive electronics suppliers to improve product design and work on the performance prediction of control to vehicle equipped electronic control system, on the other hand, it can also reduce the development costs and shorten design cycle of vehicle manufacturers and automotive electronics vendors matching chassis electronic control system as furthest as possible, to settle the problems in the design of control system as early as possible. As far, it has become one of the main research techniques when major international vehicle manufacturers and automotive electronics suppliers in the design of matching chassis electronic control system.At present major domestic vehicle manufacturer lack the capabilities of performance prediction analysis, using virtual prototyping technology, to the vehicle after equipped with ABS in design stage and the domestic evaluation of ABS Performance basically based on GB / T 13594-2003. As the evaluation method in GB, set up test projects from the perspective of product quality certification, is far from satisfying the research needs in the vehicle braking performance design and development stage. Therefore, in the entire automotive product development cycle, domestic vehicle manufacturers mostly consign the matching design to foreign company and make use of ground test after vehicle equipped ABS to carry through validation of the test set by GB, the purpose of testing was only satisfied with the braking performance through the mandatory regulations.This paper, studied problems above and combined with the R & D needs of the project (863 Program "Chang'an export cars independent integration and industrialization - integrated chassis control") taken on by our Laboratory, focused on the following two issues:1,A set methods for evaluation the longitudinal and lateral braking performance of vehicle equipped with ABS was established and simulation analysis performance prediction for braking Performance to models of Chang'an CV11 vehicle equipped with ABS had been implemented. A set of evaluation norms for evaluation of longitudinal and lateral stability performance of vehicle equipped with ABS at the entire product design and development phase of the vehicle, based on comprehensive research and summarized the methods for evaluation the ABS performance in Europe, the United States, Japan and China, has been made. Test conditions attached, include braking on the high adhesion surface, braking on the low adhesion surface , braking from high adhesion surface to low adhesion surface, braking from low adhesion surface to high adhesion surface, braking on the high split adhesion surface, braking on the low split adhesion surface, braking in turn on high adhesion surface, braking in turn on low adhesion surface. Based on this, the forecast evaluation for braking performance to the models based on the virtual prototype of Chang'an CV11 vehicle equipped ABS has been developed.(1) The utilization adhesion of the vehicle of Chang'an equipped with ABS meet regulatory requirements, and its braking distance is short than vehicles unequipped ABS. Lateral offset is very small and has a stability braking process.(2) The deceleration of the vehicle rise to a proper at the right time value when the Chang'an CV11 vehicles equipped with ABS braking from the low-adhesion surface and enter to the high-adhesion surface with the provisions of speed. Braking torque has a proper minish when braking from a high-adhesion surface to a low-adhesion surface with the provisions of speed.(3) The lateral offset of the vehicle equipped general ABS is less than the corresponding lateral offset of the vehicle unequipped ABS when in turning braking conditions, but the effect is not very good. (4) The speed of Chang'an CV11 equipped ABS is no less than the vehicle without braking when in the simulation of change lane.2,From the perspective of theoretical exploration, put forward a enhanced ABS algorithm to dynamically adjust the work region of ABS based on the turning intention of driver to solve the problem that loss of lateral stability in turning braking conditions, found in the simulation.The algorithm takes into account the theory of general ABS system ,that is to fully make use of the longitudinal adhesion coefficient and sacrificing part of the lateral force to ensure maximum longitudinal braking force. Bring forward a enhance ABS algorithm from the perspect of concerted control between the longitudinal brake performance and lateral stability of the vehicle. Its theory is to dynamically adjust the braking force of the inboard wheel and outboard wheel based on the judgement of the driver turning intention. In a certain extent, the algorithm can enhance the lateral stability in turning braking condition. It can be proved through simulation contrast between the traditional ABS and enhanced ABS in turning braking condition. And it only added a steering wheel angle sensor and yaw rate sensor based on existing hardware and software resources of ABS system. So it attempt a new way to enhance the lateral stability in turning braking condition based on existing hardware and software resources of ABS system.