【作者】 魏波；

【导师】 徐颖；

【作者基本信息】 深圳大学 ， 交通运输工程（专业学位）， 2019， 硕士

【摘要】 近年来,基于传统集中式驱动燃油车结构改造的电动汽车取得了巨大的进步。但是,这种只改变动力源,继承传统燃油车底盘结构和动力传输形式的改进,只能有限地改善整车性能。相比之下,四轮独立驱动轮毂电动汽车(下称轮毂电动汽车)采用线控系统,将驱动和制动系统集成在车轮内,从根本上改变了汽车的结构和控制。轮毂电动汽车作为一种全新的汽车形态,容易实现四轮驱动力矩和制动力矩的独立控制,在节能控制和主动安全方面具有独特优势。论文围绕优化轮毂电动汽车的转矩分配,在保证制动效能和制动稳定性的前提下,开展了轮毂电动汽车的节能与ABS的协调控制策略的研究工作,主要内容如下:(1)四轮独立驱动轮毂电动汽车的建模与仿真基于深圳大学四轮独立驱动轮毂电动汽车硬件平台,分析轮毂电动汽车的动力学原理以及各重要组成部分的工作原理,应用Matlab/Simulink和Car Sim软件搭建了四轮驱动轮毂电动汽车模型,其中包括整车动力学模型、驾驶员模型、电机模型、车载动力电池模型和电磁制动器模型。仿真时,采用Car Sim中基准车作为对比项,选取典型的汽车试验工况进行仿真试验,包括纵向的ECE速度跟踪仿真试验和纵横向耦合的双移线工况试验,完成轮毂电动汽车的动力学建模和人-车-路闭环控制系统的验证。(2)基于分层式控制框架的轮毂电动汽车节能控制策略研究依据轮毂电动汽车节能控制策略的总体结构,提出了包含参考车速输入层、运动跟踪控制层、转矩优化分配层、执行器执行层和状态观测层的分层式轮毂电动汽车节能控制结构框架。以转矩优化分配层为核心,针对驱动和制动分别建立了轮毂电动汽车能耗目标函数,考虑了ECE法规、电机最大转矩、再生制动时电池充电状态,建立了相关约束的等式和不等式,采用遗传算法和有限循环插值法对前后轴驱动和制动分配系数分别进行了寻优求解,并基于汽车实际运行工况中的影响因素,对电池SOC和车速这两个参数制定了相应的修正策略。仿真验证时,选取三种不同制动强度工况,典型循环工况NEDC和UDDS,以传统转矩分配策略作为对比进行仿真试验,完成轮毂电动汽车基于分层式控制框架的节能控制策略的有效性验证。(3)基于最佳滑移率的ABS控制策略研究分析了液压式ABS的组成和工作原理,从结构、控制目标和控制方法三个维度对比了传统液压式ABS和电磁机械式ABS。根据电磁机械式ABS的结构,结合路面类型在线识别,以最佳滑移率为控制目标,搭建了基于1/4车辆动力学模型的ABS滑模控制系统。仿真时,分别在高、低附着路面和对接路面条件下,比较了滑模控制器和PID控制器在ABS上应用的性能,以及基于最佳滑移率控制和基于固定滑移率控制的ABS制动性能。(4)再生制动与ABS的协调控制策略设计结合轮毂电动汽车的再生制动控制策略和ABS控制策略,以分层式控制结构为基础,并将采用滑模控制器的ABS植入整车制动模型,以制动强度、制动滑移率规划的再生制动转矩和电机最大再生制动转矩的最小值作为实际再生制动转矩值,设计了紧急制动工况下电磁制动器耦合再生制动的ABS的协调控制策略,并分别在高附着路面和低附着路面条件下进行了仿真验证。更多还原

【Abstract】 In recent years,great progress has been made in electric vehicles based on the structural modification of traditional centralized fuel vehicles.However,this kind of improvement inherits the traditional fuel vehicle chassis structure and power transmission form with power source changed,can merely improve the vehicle performance limited.In contrast,fourMotorized-Wheel Independent Drive Electric Vehicles(4MWIDEV)uses a wire control system,which integrates the drive and brake system into the wheel,and changes the structure and control of the vehicle fundamentally.As an all new vehicle structure,4MWIDEV can easily realize independent control of four-wheel driving and braking moment.Therefore,4MWIDEV has unique advantages in energy-saving control and active safety.Focusing on optimizing the torque distribution of 4MWIDEV,this paper studies the coordinated control strategy of energy-saving and ABS on the premise of ensuring braking efficiency and braking stability.The main work has been carried out is as follows:(1)Modeling and Simulation of 4MWIDEVBased on the hardware platform of the four-wheel independent driving electric vehicle of Shenzhen University,the dynamics of the 4MWIDEV and the working principle of its important components are analyzed.MATLAB/Simulink and Car Sim are used to establish the 4MWIDEV model,which includes vehicle dynamics model,driver model,motor model,on-board power battery model and electromagnetic brake model.For simulation,Car Sim benchmark vehicle is used as the contrast item.The typical vehicle test conditions are selected for simulation test,including the longitudinal ECE speed tracking test and the longitudinal-lateral coupling double lane change test.The results show that the dynamic modeling of 4MWIDEV and the verification of the Human-Vehicle-Road closed-loop control system are completed.(2)Research on Energy-saving Control Strategy of 4MWIDEV Based on Hierarchical Control FrameworkAccording to the overall structure of energy-saving control strategy for 4MWIDEV,a hierarchical energy-saving control structure framework is proposed,which includes reference speed input layer,motion tracking control layer,torque optimization distribution layer,actuator execution layer and state observation layer.Taking the optimal distribution layer of torque as the core,the objective functions of energy consumption for driving condition and braking condition of 4MWIDEV are established respectively.Moreover,relevant constraints such as ECE regulation,maximum torque of motor and battery charging state during regenerative braking are taken into consideration,so that the equations and inequalities are established.The optimal solutions of front and rear axle driving and braking distribution coefficients are obtained respectively by genetic algorithm and finite cycle interpolation method.Then,based on the factors affecting the actual operating conditions of automobiles,the corresponding correction strategies for battery SOC and vehicle speed are formulated.For simulation and verification,three different braking intensity conditions,typical cycle conditions NEDC and UDDS,are selected to carry out simulation tests by comparing with the traditional torque distribution strategy.The effectiveness of the energy-saving control strategy based on Hierarchical Control Framework for 4MWIDEV is verified.(3)Study on ABS Control Strategy Based on Optimal Slip RateFirst of all,the composition and working principle of hydraulic ABS are analyzed.Then,the traditional hydraulic ABS and electromagnetic mechanical ABS are compared from three dimensions: structure,control objectives and control methods.According to the structure of electromagnetic mechanical ABS,the on-line recognition system of road type and the ABS sliding mode control system based on 1/4 vehicle dynamics model is built.For simulation,the performance of sliding mode controller and PID controller applied in ABS,and the braking performance of ABS based on optimal slip rate control and fixed slip rate control were both compared under the conditions of high adhesion road,low adhesion road and opposite roads respectively.(4)Design of coordinated control strategy between regenerative braking system and ABS.Combined with regenerative braking control strategy and ABS control strategy of 4MWIDEVs,based on hierarchical control structure,ABS with sliding mode controller is embedded in braking system of the vehicle model.And then,regenerative braking torque is planned by braking intensity and slip rate.The coordinated control strategy of ABS for electromagnetic brake coupled regenerative braking system under emergency braking condition is designed and simulated on high and low adhesion road.更多还原