不同道路条件下汽车恒速下坡控制仿真研究

Simulation of vehicle downhill control at constant speed under different road conditions

实现汽车恒速下坡控制对于提高汽车运输效率和安全性具有重要意义。针对加装液力缓速器汽车恒速下坡控制的特点,通过分析汽车下坡缓速制动过程,建立汽车下坡缓速器制动仿真模型。根据缓速器缓速制动原理设计了基于Matlab/Stateflow逻辑控制的恒速控制器,在Matlab/Simulink中选取混凝土、卵石、砂石等不同路面条件对汽车恒速下坡过程进行仿真分析,得出了充液率调节值对车速变化的影响关系,得到了汽车在不同路面条件下实现恒速制动的充液率合理调节取值。仿真结果表明液力缓速器单独作用于汽车制动可以实现恒速下坡控制,路面条件与液力缓速器充液率调节值大小对恒速控制性能有着重要的影响。

It is of great significance for improving efficiency and safety of vehicle transport to achieve constant speed downhill control of vehicle.Aiming at the characteristics of constant speed downhill control with hydraulic retarder,the braking simulation model of vehicle downhill retarder was established through analyzing the slow braking process of vehicle downhill.According to the braking principle of retarder,a constant speed controller based on Matlab/Stateflow logic control was designed.In Matlab/Simulink,different road conditions such as concrete,pebble and gravel were selected to simulate and analyze the process of automobile constant speed downhill.The influence of the adjusting value of liquid filling rate on the change of vehicle speed was obtained,and the reasonable value of filling rate for realizing constant speed braking under different road conditions was obtained.The simulation results show that the hydraulic retarder acting alone on the brake of the vehicle can achieve constant speed downhill control.The pavement conditions and the adjustable value of the hydraulic retarder filling rate have an important impact on the constant speed control performance.