基于液力缓速器换挡控制的半挂汽车列车制动稳定性

Braking stability of tractor-semitrailer based on gear-shifting strategy of hydraulic retarder

针对液力缓速器改变半挂汽车列车车轮制动力分配会影响制动稳定性的问题,提出了一种液力缓速器换挡控制策略。根据牵引车后轴车轮与半挂车车轮的转速关系,对液力缓速器工作挡位进行主动调控。以半挂汽车列车车轮最佳抱死顺序为控制目标,采用Matlab/Stateflow设计换挡控制策略,并与半挂汽车列车整车动力学Matlab/Simulink模型联合仿真,分别模拟直线制动车轮抱死情况和直线制动受侧向力时的横向运动情况。仿真结果表明:本文换挡控制策略能使半挂汽车列车保持最佳抱死顺序,减小在部分路面上的制动距离,并且提高汽车列车直线行驶制动受侧向力作用时的横向稳定性。

The hydraulic retarder may change the distribution ratio the braking power of the tractor- semitrailer that negatively affects the braking stability. To solve this problem, a gear-shifting strategy of the hydraulic retarder is proposed. The strategy is designed to actively change the gear of the hydraulic retarder based on the relationship between the rear wheel of the tractor and the wheel of the semitrailer. With goal to optimize the locking sequence of the tractor-semitrailer, the Matlab/ Stateflow is applied to design the gear-shifting strategy. Then this strategy is associated with the dynamic model of the tractor-semitrailer built with Matlab/Simulink to study the braking sequence during straight braking and the lateral motion during straight braking with lateral force. Simulation results show that the proposed strategy can help keep the optimum braking sequence, decrease the braking distance on the road with particular tire-road adhesion and improve the lateral stability of the tractor-semitrailer.