面向线控制动车辆单轮制动失效的稳定性控制

Single-wheel brake failure stability control for vehicle equipped with brake-by-wire system

基于线控制动系统四轮可独立控制的特点,提出一种协同线控转向与线控制动的制动力实时分配的控制方法。该方法根据三轮富余制动力能否补偿失效轮损失制动力,按制动强度分为轻度、中度和重度制动3种工况,针对重度制动工况下制动力补偿不足问题,基于积分滑模控制方法设计前轮主动转向器,综合考虑单轮制动失效时各轮垂直载荷的变化和前轮转角介入后轮胎力的耦合,采用序列二次规划算法(sequental quadratic programming,SQP),实时分配剩余三轮制动力。仿真结果表明:在不同制动强度及不同轮制动失效下所提控制方法相较于无控制,横向跑偏分别减少了89.98%、91.90%、96.96%、89.62%,制动强度至少达到正常制动时的97.5%。因此,该控制方法在保证横向稳定性的同时最大限度地满足驾驶员的制动期望,有效抑制因单轮制动失效导致的车辆跑偏甩尾等问题。

To address the issues of braking performance and stability in the event of a single-wheel brake failure in a brake-by-wire system,this paper proposes a control strategy for real-time optimization of braking force allocation between cooperative brake-by-wire and steer-by-wire systems.With this method,the braking intensity is categorized into light,moderate,and heavy levels based on whether the three remaining wheels can compensate for the loss of braking force from the failed wheel.To address the issue of insufficient braking force compensation under heavy braking conditions,a front wheel active steering gear based on integral sliding mode control method is designed.Considering the changes in the vertical load of each wheel when a single wheel brake failure occurs and the coupling effect of the tire forces after the intervention of front-wheel steering,we employ a Sequential Quadratic Programming(SQP)algorithm to distribute the remaining three wheel braking forces in real-time.Our simulation results demonstrate the proposed control method reduces lateral deviation by 89.98%,91.90%,96.96%,and 89.62%compared with the case without control under different braking intensities and different wheel brake failures.Meanwhile,it ensures the braking intensities reach at least 97.5%of the normal braking level and guarantees stability while satisfying the driver’s braking expectations to the maximum extent,effectively addressing issues such as vehicle deviation and over-steering caused by single-wheel brake failure.