虚拟轨道有轨电车循迹特性及力矩分配研究

发布时间：2018-04-28 12:09

本文选题：虚拟轨道有轨电车 + 道路几何特性　；参考：《西南交通大学》2017年硕士论文

【摘要】：随着我国经济的飞速发展,城市交通方式呈现出多元化的发展态势。在汽车、地铁等现有城市交通工具的基础上,考虑能源利用、资源整合以及交通便利性等因素,提出一种新型城市轨道交通方式,即一种基于橡胶车轮和虚拟轨道技术的有轨电车。此种车辆属于四轮毂电机驱动的智能车辆,其既保有轨道交通大运量的特点又兼顾了汽车的机动灵活性。车辆自主循迹及驱动控制是虚拟轨道有轨电车的关键技术之一,为此针对虚拟轨道有轨电车系统,主要完成以下几个方面的研究内容:首先,建立包含侧向和横摆的线性二自由度车辆操纵模型,研究其动力学性能及操纵特性规律,并分析"魔术公式"轮胎模型在不同工况下的受力状况,然后建立包含纵向、侧向、横摆以及车轮旋转的七自由度车辆模型。其次,建立考虑道路几何特性对车辆循迹效果影响的控制模型,道路几何特性包括跟踪路径的大地坐标、道路曲率以及道路宽度,并采用离散数表的方式表示。根据公路线路设计相关理论,建立道路曲率和道路宽度对车辆理想纵向速度影响模型。在方向控制方面,建立基于侧向加速度反馈的驾驶员模型。在此基础上,综合考虑速度和方向联合控制,使用"预瞄-跟踪"驾驶员建模理论对任意路径进行循迹。再次,为描述车辆实际线路下的循迹效果,引入任意路径循迹误差计算方法,将循迹误差作为衡量线路循迹效果的评价指标,该指标为统计意义下的优化指标。针对大曲率道路工况下车辆循迹偏差较大的现象,为优化大曲率路段循迹效果,提出循迹误差最优准则。根据循迹优化指标对车辆理想纵向速度进行修正,并在此基础上建立方向盘转角修正模型,通过循迹误差最优准则选取不同速度区间下的修正系数,在大曲率道路工况下对车辆循迹进行修正,其适用于优化大曲率路段的循迹效果。最后,建立基于路径跟踪的全轮力矩分配算法,在线路循迹效果较优基础上,提取车辆路径跟踪所需的运动学及动力学参数,建立车辆轮胎附着系数最优作为优化目标的力矩分配方法,并推导出各轮胎瞬态的力值。考虑驱动-转弯联合工况下的"魔术公式"轮胎逆模型,根据轮胎瞬态的力值反求出轮胎滑转率和轮胎侧偏角,以此求出该瞬态下四轮转角指令和驱动力矩指令。综上所述,对虚拟轨道有轨电车循迹特性和力矩分配算法进行研究,为虚拟轨道有轨电车研制提供了理论基础和技术支持。
[Abstract]:With the rapid development of China's economy, urban transportation mode presents a diversified development trend. On the basis of existing urban vehicles such as automobiles and subways, and taking into account such factors as energy utilization, resource integration and transport convenience, a new type of urban rail transit is proposed. That is, a tram based on rubber wheels and virtual track technology. This kind of vehicle is an intelligent vehicle driven by four hub motors, which not only retains the characteristics of heavy rail traffic volume, but also takes into account the flexibility of the vehicle. Autonomous tracking and driving control of vehicles is one of the key technologies of virtual tram. For this reason, the following aspects are mainly studied in the virtual track tram system: first of all, A linear two-degree-of-freedom vehicle control model with lateral and transverse pendulum is established to study its dynamic performance and control characteristics, and to analyze the force condition of the "magic formula" tire model under different working conditions, and then to establish a longitudinal and lateral vehicle control model. A 7-DOF vehicle model of yaw and wheel rotation. Secondly, a control model considering the influence of road geometry on vehicle tracking effect is established. The road geometry includes geodetic coordinates, road curvature and road width, which are represented by discrete number table. According to the theory of highway route design, the influence model of road curvature and road width on the ideal longitudinal speed of vehicle is established. In the aspect of direction control, the driver model based on lateral acceleration feedback is established. On this basis, considering the combined control of speed and direction, the "preview-tracking" driver modeling theory is used to track any path. Thirdly, in order to describe the track effect of the actual vehicle, an arbitrary path tracking error calculation method is introduced, and the track error is taken as the evaluation index to evaluate the track tracking effect, which is an optimization index in the statistical sense. In order to optimize the track effect of large curvature road, the optimal criterion of tracking error is put forward in order to optimize the track effect of the large curvature road, aiming at the phenomenon that the vehicle track deviation is large under the working condition of the road with large curvature. According to the track optimization index, the vehicle ideal longitudinal velocity is modified, and the steering wheel angle correction model is established on this basis. The correction coefficient of different speed ranges is selected by the track error optimal criterion. The vehicle track is modified under the condition of large curvature road, which is suitable for optimizing the track effect of large curvature road. Finally, an algorithm of full wheel torque assignment based on path tracking is established, and the kinematics and dynamics parameters of vehicle path tracking are extracted on the basis of better track performance. The torque distribution method of vehicle tire adhesion coefficient as the optimization objective is established, and the transient force values of each tire are derived. Considering the "magic formula" tire inverse model under the combined driving and turning conditions, the tire slip rate and the tire side deflection angle are inversely calculated according to the transient force value of the tire, and the four wheel rotation angle instruction and the driving torque instruction under the transient condition are obtained. To sum up, the tracking characteristics and torque allocation algorithm of virtual track tram are studied, which provides the theoretical basis and technical support for the development of virtual track tram.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U482.1

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