【作者】 曾鹏；

【导师】 王开凤；

【作者基本信息】 武汉理工大学 ， 道路与铁道工程， 2018， 硕士

【摘要】 我国西南山区和南方潮湿地区的路面在冬季寒冷气候下容易出现凝冰现象。路面凝冰冰层完全屏蔽了路面抗滑结构,使汽车轮胎与冰面直接接触,附着系数急剧降低,汽车在凝冰路面极易发生横向失稳,且制动距离大大增加。目前,汽车横向稳定控制的研究主要考虑湿滑积雪等一般低附着路面,对凝冰情况的考虑较少;对于凝冰行车安全的道路线形设计研究也有所欠缺。因此,本文依托于国家自然科学基金(51408446)“基于轮胎复杂接触效应的凝冰沥青路面抗滑特性研究”,针对汽车在凝冰路面行驶的横向与纵向安全性,分别从汽车的横向稳定控制和凝冰弯道路段的停车视距设计两个方面来研究,综合车辆控制和路线设计两方面来保证汽车冰面行驶安全性。论文首先介绍了路面凝冰的产生和除冰方法,对比试验和半经验轮胎模型确定凝冰时光滑冰面的附着系数。针对凝冰路面的超低附着特点,设计了以横摆角速度为目标变量,基于直接横摆力矩控制策略和滑模变结构控制算法的汽车横向稳定控制器;控制器采用单侧双轮制动来获得在冰面上更大的附加横摆力矩,并根据冰面附着椭圆的限制设计了制动力分配。在Matlab/Simulink中建立冰面仿真模型,验证横向稳定控制器在两种转向极限工况下的控制效果。仿真结果说明:无控制的汽车在凝冰路面即使低速行驶转向时汽车也会失稳侧滑;所设计的横向稳定控制器对汽车在冰面条件下的转向稳定性和操控性有较好的控制效果;控制器的控制效果有极限,在中高速的单移线极危工况下依然可能失稳。基于直线路段的停车视距计算,论文提出了弯道路段的停车视距计算方法,并通过CarSim的制动仿真试验,验证了计算模型的正确性。依据得到的弯道视距计算方法,给出了不同圆曲线参数下的凝冰弯道路段停车视距作为参考,并根据道路线性设计规范反算出现有道路发生凝冰时,弯道路段的安全通行车速。更多还原

【Abstract】 Ice easily occurs on road pavement which is in southwest mountainous areas and wet areas in the south of China.The ice layer on pavement completely shields the antisliding structure.So,tires contact with the ice directly and the road pavement adhesion coefficient is drastically reduced.Cars are prone to lateral instability on icing roads,and the braking distance is greatly increased.At present,the research on the lateral stability control of vehicle mainly considers generally low-adherent roads such as wet skis and snow,and there are few considerations for the icing conditions;There is also a lack of research on the road alignment design for icing road safety.In view of the horizontal and vertical safety of cars driving on icing roads,this paper which relies on the National Natural Science Foundation of China(51408446)"skid-resisting characteristics of asphalt pavement with glazing ice by considering complex contacting effect between tire and pavement",studies the lateral stability control of the car and the stopping sight distance design of the curve section on icing road respectively and combining vehicle control and route design to ensure the safety of car ice driving.Firstly,the generation and deicing methods of road condensing ice were introduced by this paper.According to the experimental and semi-empirical tire models,the adhesion coefficient of the smooth ice surface during freezing is obtained.Aiming at the ultra-low adhesion characteristics of icing road,a lateral stability controller based on direct yaw moment control strategy and sliding mode control is designed with yaw rate as the target variable;the controller adopts unilateral two-wheel braking.To obtain a larger additional yaw moment on the ice,and to design the braking force distribution based on the constraints of the ice attached to the ellipse.The controller uses a singlesided two-wheel brake to obtain a larger additional yaw moment on the ice surface,and a brake force distribution is designed based on the limit of the attached ice ellipse.Vehicle simulation model is established in Matlab/Simulink to verify the control effect of the lateral stability controller under two kinds of steering limit conditions.The simulation results show that the uncontrollable car will lose stability when the car turns on icing road at low speeds;The designed lateral stability controller has better control effect on steering stability and maneuverability of the car under ice conditions;Vehicles equipped with controllers may still be unstable under the extremely dangerous conditions of high-speed obstacle avoidance.Based on the calculation of stopping sight distance for the straight road,a stopping sight distance calculation method for curved road was proposed,and validates the correctness of the calculation model through CarSim’s braking simulation test.According to the curve stopping sight distance calculation method,the stopping sight distance of the icing road section with different parameters of the circular curve is given as a reference;According to the road linear design specification,it is used to calculate the safe traffic speed of the curved road when occurs on road.更多还原