【作者】 林涛；

【导师】 赵又群；

【作者基本信息】 南京航空航天大学 ， 机械， 2023， 硕士

【摘要】 随着现代汽车工业的发展,人们对于车辆的操纵稳定性和行驶安全性提出了更高的要求。分布式驱动具有传动链短、传动效率高和响应速度快等特点,因此分布式驱动电动汽车在整车稳定性控制、优化车辆底盘结构、提高能量利用效率等方面有着很大的优势。车轮作为车辆与地面接触的唯一部件,机械弹性车轮克服了传统充气车轮由于不耐穿刺、易爆胎的缺陷。因此本文将选用匹配机械弹性电动轮(MEEW)的分布式驱动车辆作为研究对象,以提高车辆的横摆稳定性为目标,通过理论推导和模拟仿真验证的方式对车辆横摆稳定性控制的关键问题展开研究。本文主要研究内容包括以下方面:(1)匹配机械弹性电动轮的分布式驱动车辆动力学建模和质心侧偏角-质心侧偏角速度相平面稳定域边界的划分:在CarSim中将传统车辆模型改造成为分布式驱动电动汽车模型。对机械弹性车轮的结构工作原理等情况进行介绍。基于机械弹性车轮的纵向力和侧向力实验数据,选用魔术公式轮胎模型对轮胎力进行描述,并通过遗传算法对魔术公式轮胎模型的参数进行辨识。在Simulink中建立轮毂电机模型并建立驾驶员车速跟踪模型。根据所选车辆模型,建立质心侧偏角-质心侧偏角速度稳定性相平面图,分别考虑了车速,路面附着系数,前轮转角三个因素对于稳定性边界的影响,并对稳定性边界进行划分和参数拟合。(2)基于无迹卡尔曼滤波(UKF)和自适应无迹卡尔曼滤波(AUKF)的机械弹性电动轮式车辆状态估计:对卡尔曼滤波算法进行了概述,并给出了UKF和AUKF的详细推导过程以及比较分析。基于三自由度车辆模型,采用UKF和AUKF理论设计了匹配机械弹性车轮的分布式驱动车辆的状态估计算法。然后设置了不同的工况对上述估计器进行了验证,试验表明AUKF比UKF估计效果要好,可以很好的估计车辆的横摆角速度和质心侧偏角等参数,为后文的研究提供了有力的基础。(3)基于扩张状态观测器(ESO)的横摆稳定性控制器的设计:对车辆的稳定性特征参数进行分析,介绍了匹配机械弹性车轮的分布式驱动车辆横摆稳定性控制器的整体架构。建立了考虑车轮侧偏刚度不确定性摄动的车辆二自由度模型。在上层控制器中分别设计基于ESO的横摆角速度和质心侧偏角积分终端滑模控制器,并进行了稳定性和有限时间收敛证明。基于质心侧偏角-质心侧偏角速度相平面划分的稳定域边界,设计了切换控制权重系数,实现横摆角速度控制器和质心侧偏角控制器的平滑切换。在下层控制器中以轮胎利用率最小为优化目标,基于二次规划方法设计转矩优化分配控制器,实现下层转矩优化分配。(4)匹配机械弹性电动轮的分布式驱动车辆横摆稳定性控制仿真研究:在CarSim/Simulink联合仿真平台中对本文中设计的基于ESO的横摆稳定性控制器进行仿真验证,设置不同的路面附着系数进行双移线和蛇形工况的仿真试验。仿真结果表明,本文设计的基于ESO的横摆稳定性控制器可以明显提高匹配机械弹性电动轮的分布式驱动车辆的横摆稳定性,保证车辆的行驶安全。更多还原

【Abstract】 With the development of modern automobile industry,people raise higher requirements for vehicle handling stability and driving safety.Distributed drive has the advantages of short transmission chain,high transmission efficiency and fast response speed.Therefore,distributed drive vehicle has great advantages in vehicle stability control,optimization of vehicle chassis structure,and improvement of energy utilization efficiency.The traditional pneumatic wheel has potential safety hazards due to the shortcomings of imperviousness to puncture and easy tire blowout,while the mechanical elastic wheel(MEEW)overcomes above shortcomings.So this thesis selects the distributed drive vehicle matched with the mechanical elastic electric wheel as the research object,aiming to improve the yaw stability of the vehicle,and carry out research on the key issues of vehicle yaw stability control through theoretical derivation and simulation verification.The main research contents include:(1)Established vehicle model of distributed drive vehicle which matched mechanical elastic electric wheels and division of the phase plane stability domain between the slide slip angle and the slide slip angle rate: Retrofit traditional vehicles in CarSim to build a distributed drive electric vehicle model.The structure and working principle of mechanical elastic wheel are introduced.Based on the experimental data of longitudinal force and lateral force of the mechanical elastic wheel,the magic formula tire model is used to describe the tire force,and the parameters of the magic formula tire model is identified by genetic algorithm,and then the identified model is imported into the software.In-wheel motor model and the driver’s vehicle speed tracking model are built in simulink.According to the selected vehicle model,a phase plane diagram of slide slip angle-slide slip angle rate is established.The influence of vehicle speed,road adhesion coefficient and front wheel angle on the stability boundary is considered respectively,and the stability boundary is divided and parameters are fitted.(2)State estimation of mechanically elastic electric wheeled vehicles based on unscented Kalman filter(UKF)and adaptive unscented Kalman filter(AUKF): The Kalman filter algorithm is summarized,and the detailed derivation process and comparative analysis of UKF and AUKF are given.Based on the three-degree-of-freedom vehicle model,UKF and AUKF theories are used to design the state estimation algorithm for a distributed drive vehicle with mechanically elastic wheels.Then,different working conditions are set to verify the above estimator.The test results shows that AUKF has better estimation effect than UKF,and can estimate the vehicle’s yaw rate and slide slip angle well,which provides a powerful basis for the following research.(3)Design of yaw stability controller based on extended state observer(ESO): The stability characteristic parameters of the vehicle are analyzed,and the overall architecture of the yaw stability controller of the distributed driving vehicle with mechanical elastic wheels is introduced.A vehicle two-degree-of-freedom model considering the uncertainty of wheel cornering stiffness perturbation is established.In the upper controller,the ESO-based yaw rate and slide slip integral terminal slidingmode controllers are designed respectively,and the stability and finite-time convergence are proved.Based on the phase plane,the switching control weight coefficient is designed to achieve smooth switching between the yaw rate controller and the slide slip angle controller.Based on the quadratic programming method,the lower-layer torque optimal distribution controller is designed,and the optimization goal is to minimize the tire utilization rate to realize the lower-layer torque optimal distribution.(4)Simulation research on yaw stability control of distributed drive vehicle matching mechanical elastic electric wheel: In the CarSim/Simulink co-simulation platform,the yaw stability controller based on the extended state observer is simulated and verified,and different road adhesion coefficients are designed to carry out the simulation tests of double line shifting and serpentine conditions.The simulation results show that the yaw stability controller based on the extended state observer designed in this thesis can significantly improve the yaw stability of the distributed drive vehicle matched with the mechanical elastic electric wheel,and ensure the driving safety of the vehicle.更多还原