基于矢量空间纯电动车三自由度建模与验证

3-DOF Modeling and Verification for Electric Vehicle Based on Vector Space

建立电动车运动坐标系,利用矢量空间数学工具和刚体力学原理,建立四轮独立转向、四轮独立驱动的电动车运动学数学模型,模型包含了纵向、侧向、横摆3个自由度。同时根据直流无刷轮毂电机的电气特性建立了轮毂电机的数学模型。模型使用了课题组试验车的参数,在相同的油门输入与方向盘输入的情况下,分别做了实车实验与模型仿真实验,采集两组实验输出的速度、横摆角速度、质心侧偏角数据。通过比较试验车与仿真模型输出的数据验证了数学模型的准确性。利用已经建立的数学模型,研究高速状态下后轮转角对电动车的横摆角速度和质心侧偏角的影响,从实验结果可以看出,实施对后轮转角的控制可以有效改变电动车的横摆特性和质心侧偏角特性。此外,论文对模型的局限性进行了分析,明确该数学模型适用的场合以及使用该模型时应注意的事项。

A mathematical model for four-wheel-steering-four-wheel-driving electric vehicle is established based on the vector space and rigid body mechanics principle. This model contained three degrees of freedom including longitudinal freedom, lateral freedom and yaw freedom. Meanwhile, a model was established for hub motor based on its electrical characteristics. This model was built with parameters of an experimental car. Experiment was done with both real vehicle and mathematical model. By comparing the two experimental data, the mathematical model was proved to be accurate. With the established mathematical model, the paper studied four-wheel steering effects on EV control performance. Through the simulation results, implementation of control of the rear wheel Angle can effectively change the EV control performance. In addition, this paper analysed the limitation of the model, declared the model applicable occasions and matters that should be paid attention to when using the model.