Decentralized Dynamic Event-Triggered Communication and Active Suspension Control of In-Wheel Motor Driven Electric Vehicles with Dynamic Damping

This paper addresses the co-design problem of decentralized dynamic event-triggered communication and active suspension control for an in-wheel motor driven electric vehicle equipped with a dynamic damper. The main objective is to simultaneously improve the desired suspension performance caused by various road disturbances and alleviate the network resource utilization for the concerned in-vehicle networked suspension system. First, a T-S fuzzy active suspension model of an electric vehicle under dynamic damping is established. Second,a novel decentralized dynamic event-triggered communication mechanism is developed to regulate each sensor's data transmissions such that sampled data packets on each sensor are scheduled in an independent manner. In contrast to the traditional static triggering mechanisms, a key feature of the proposed mechanism is that the threshold parameter in the event trigger is adjusted adaptively over time to reduce the network resources occupancy. Third, co-design criteria for the desired event-triggered fuzzy controller and dynamic triggering mechanisms are derived. Finally, comprehensive comparative simulation studies of a 3-degrees-of-freedom quarter suspension model are provided under both bump road disturbance and ISO-2631 classified random road disturbance to validate the effectiveness of the proposed co-design approach. It is shown that ride comfort can be greatly improved in either road disturbance case and the suspension deflection, dynamic tyre load and actuator control input are all kept below the prescribed maximum allowable limits, while simultaneously maintaining desirable communication efficiency.

MPC-based Torque Distribution for Planar Motion of Four-wheel Independently Driven Electric Vehicles:Considering Motor Models and Iron Losses

The most critical obstacle for four-wheel independently driven electric vehicles(4WID-EVs)is the driving range.Being the actuators of 4WID-EVs,motors account for its major power consumption.In this sense,by properly distributing torques to minimize the power consumption,the driving range of 4WID-EV can be effectively improved.This paper proposes a model predictive control(MPC)-based torque distribution scheme,which minimizes the power consumption of 4WID-EVs while guaranteeing its tracking performance of planar motions.By incorporating the motor model considering iron losses,the optimal torque distribution can be achieved without an additional torque controller.Also,for this reason,the proposed control scheme is computationally efficient,since the power consumption term to be optimized,which is expressed as the product of the motor voltages and currents,is much simpler than that derived from the efficiency map.With reasonable simplification and linearization,the MPC problem is converted to a quadratic programming problem,which can be solved efficiently.The simulation results in MATLAB and CarSim co-simulation environments demonstrate that the proposed scheme effectively reduces power consumption with guaranteed tracking performance.

The Summary of the Research on the Compound Braking Strategy of Four Wheel Hub Motor Drive Electric Vehicle

This paper describes in detail three kinds of typical compound braking strategy of wheel motor drive electric vehicle and summarizes the current commonly used strategies based on the three typical strategies developed. In the end, a new compound braking strategy is proposed;that is, we take braking mode classify, ECE regulations and SOC value of the battery as an important reference of braking force that joins the motor braking force, as well as we join the different identification models;according to the different braking modes, the purpose is that we can apply the different braking program.

Torque Distribution of Electric Vehicle with Four In-Wheel Motors Based on Road Adhesion Margin

With the worsening of energy crisis and environmental pollution,electric vehicles with four in?wheel motors have been paid more and more attention. The main research subject is how to reasonably distribute the driving torque of each wheel. Considering the longitudinal motion,lateral motion,yaw movement and rotation of the four wheels,the tire model and the seven DOF dynamic model of the vehicle are established in this paper. Then,the torque distribution method is proposed based on road adhesion margin,which can be divided into anti ? slip control layer and torque distribution layer. The anti?slip control layer is built based on sliding mode variable structure control,whose main function is to avoid the excessive slip of wheels caused by road conditions. The torque distribution layer is responsible for selecting the torque distribution method based on road adhesion margin. The simulation results show that the proposed torque distribution method can ensure the vehicle quickly adapt to current road adhesion conditions,and improve the handling stability and dynamic performance of the vehicle in the driving process.

Multi-objective Optimization of Differential Steering System of Electric Vehicle with Motorized Wheels

A differential steering system is presented for electric vehicle with motorized wheels and a dynamic model of three-freedom car is built.Based on these models,the quantitative expressions of the road feel,sensitivity,and operation stability of the steering are derived.Then,according to the features of multi-constrained optimization of multi-objective function,a multi-island genetic algorithm(MIGA)is designed.Taking the road feel and the sensitivity of the steering as optimization objectives and the operation stability of the steering as a constraint,the system parameters are optimized.The simulation results show that the system optimized with MIGA can improve the steering road feel,and guarantee the operation stability and steering sensibility.

轮毂电动机驱动车辆并联式复合制动策略

基于并联式轮毂电动机驱动实车构型,分析影响制动能量回收效率的主要因素,采用联邦卡尔曼滤波纵向车速估计算法,提出了三层式复合制动控制策略.该策略中的制动决策层根据踏板输入信号和行驶状态来识别制动工况,并进入相应的制动模式.制动控制层根据制动决策层的指令,在常规制动工况下通过粒子群优化(PSO)算法优化前、后轮电制动力矩分配,实现电池有效回收效率最大化;紧急制动工况下,通过模糊自整定PID算法实现车辆在不同附着路面上各轮滑移率的安全有效控制,优化了制动防抱死控制的鲁棒性,提高制动安全性.制动执行层响应制动控制层的指令,设计了电制动补偿机制,以迅速补偿调节各轮轮缸的压力误差,提高车辆制动稳定性.最后实车验证了该复合控制策略的有效性.

A Fuzzy-based Sliding Mode Control Approach for Acceleration Slip Regulation of Battery Electric Vehicle

Due to quick response and large quantity of electric motor torque,the traction wheels of battery electric vehicle are easy to slip during the initial phase of starting.In this paper,a sliding mode control approach of acceleration slip regulation is designed to prevent the slip of the traction wheels.The wheel slip ratio is used as the state variable for the formulation of system dynamics model.The fuzzy algorithm is utilized to adjust the switch function of sliding mode controller.After stability and robustness analysis,the sliding mode control law is transferred into C code and downloaded into vehicle control unit,which is validated under wet and dry road conditions.The experimental results with a small overshoot and a quick response during starting indicate that the sliding mode controller has good control efect on the slip ratio regulation.This article proposes an acceleration slip regulation method that improves the safety during acceleration for battery electric vehicle.

考虑道路识别的四驱电动汽车再生制动策略

为了充分利用路面附着条件分配再生制动力,提高制动能量回收率,根据双电动机四驱结构电动汽车复合制动系统的特点,对其制动能量回收控制策略进行了研究.分析了驱动轮与地面附着特性,设计了道路识别器来计算每个轮胎与当前路面之间的峰值附着系数,并使用模糊控制策略确定每个车轮与8种道路的滑移率和附着利用率的相似输入.根据双电动机外部特性的制动力分配关系,提出了使更多制动能量回馈给电池的策略.结果表明:制动强度为0.3时,能量回收率为65.55%,具有较高的回收效率.

基于路面影响因子的轮毂电机驱动车辆自适应转矩控制

为实现轮毂电机驱动越野车辆在附着条件多变、路面起伏不定的复杂环境中动力性和稳定性的多目标优化,提出一种基于路面影响因子的自适应转矩控制策略。以滚动阻力差异、空气阻力归一化比例、坡度阻力归一化比例、路面附着差异方差以及最小路面附着系数5个特征参数作为输入,并基于模糊理论方法搭建路面影响因子五参数辨识模型。基于辨识出的路面影响因子,开发整车动力性和稳定性多目标优化自适应转矩控制策略,构建了三层式控制架构:顶层引入路面影响因子对加速度紧迫程度进行判定,采用模型预测控制算法得到期望总驱动力;中层为目标决策层,以最优滑转率为目标决策驱动防滑力矩,并基于路面行驶阻力,决策期望前馈补偿力矩;下层为转矩分配层,以需求总驱动力及轮胎利用率作为控制目标,引入路面影响因子优化两者权重系数,以多约束条件的混合优化算法对转矩进行自适应控制。利用Matlab/Simulink-CarSim联合仿真平台进行仿真,基于实车进行验证。结果表明,在低附着路面,在0.2s内快速完成滑转率抑制;在对开路面,侧向位移接近0;在大扭曲路面,避免腾空车轮出现大滑转率,滑转率最高0.2。

永磁轮毂电机技术发展综述

电传动技术是车辆实现全电化的重要基础,电驱动系统是电动车辆的动力核心,而轮毂电驱系统是电驱动系统的终极驱动形式,轮毂电机的性能在轮毂电驱系统中具有决定性作用。首先,该文介绍了轮毂电驱系统的结构形式,对不同磁场类型的轮毂电机的优缺点进行了分析;其次,调研了目前市场主流轮毂电机产品的性能参数,为轮毂电机的研发提供参考目标;然后,针对轮毂电机高功率/转矩密度、宽转速运行范围、高运行效率和高可靠性等需求,分别调研了径向磁场、轴向磁场和横向磁场等不同类型的永磁轮毂电机的研究现状;最后,展望了不同磁场类型的永磁轮毂电机的发展方向。

分布式驱动电动汽车执行器失效容错控制研究

为了提高单电机故障状态下分布式驱动电动汽车的稳定性,提出了一种驱动力重构和主动前轮转向(AFS)结合的容错控制方法。首先,设计滑模控制器,控制输入量为横摆角速度和质心侧偏角,进而对所需横摆力矩和前轮附加转角进行控制。其次,建立电机故障状态下的整车驱动力优化分配模型。当车辆电机出现故障时,运用二次规划算法对各电机转矩进行重构分配。同时,当某一电机发生故障且同侧电机出现输出饱和而无法提供足够的横摆力矩时,通过主动前轮转向提供附加横摆力矩。最终搭建CarSim/Simulink联合仿真模型进行验证,结果显示,所采用的容错控制方法可有效提高车辆稳定性和动力性。

小曲率路面车辆差动转向与横摆稳定性集成控制研究

为减小车辆在前轮转向系统失效的负面影响,保证转向系统的瞬态控制性能,本文提出差动转向控制与横向稳定性控制相结合的控制方法,通过调节左右轮毂电机转矩形成横摆力矩,实现对系统完全失效车辆的转向控制与横向稳定性控制。首先设计基于LQR差动转向控制器跟踪参考前轮转角与参考横摆角速度,保证车辆轨迹跟踪能力,然后设计基于模糊PID横向稳定性控制器跟踪参考质心侧偏角,保证车辆横摆稳定性,两者构成双闭环控制系统将控制量最终转化为横摆力矩,实现车辆的集成控制。最后通过Simulink-Carsim联合仿真验证,仿真结果表明差动转向系统能够在前轮转向系统失效情况下实现车辆转向控制,并在横向稳定性控制系统的作用下有效地提高了车辆瞬态控制性能。

Primary studies on integration optimization of differential steering of electric vehicle with motorized wheels based on quality engineering

The model of the differential steering system(DSS) of electric vehicle with motorized wheels and the three-degree-of-freedom dynamic model of vehicle are built.Based on these models,the concepts and quantitative expressions of steering road feel,steering portability and steering stability are proposed.Through integrating the Monte Carlo descriptive sampling,elitist non-dominated sorting genetic algorithm(NSGA-II) and Taguchi robust design method,the system parameters are optimized with steering road feel and steering portability as optimization targets,and steering stability and steering portability as constraints.The simulation results show that the system optimized based on quality engineering can improve the steering road feel,guarantee steering stability and steering portability and thus provide a theoretical basis for the design and optimization of the electric vehicle with motorized wheels system.

Multidiscipline collaborative optimization of differential steering system of electric vehicle with motorized wheels

Based on the multidiscipline design optimization theory, a multidiscipline collaborative optimization model of the differential steering system of electric vehicle with motorized wheels is built, with the steering economy as the main system and the steering road feel, the steering flexibility and the mechanic character of the steering sensors as the subsystems. Considering the coupled relationship of each discipline, the main system is optimized by the multi-island algorithm and the subsystems are optimized by the sequential quadratic programming algorithm. The simulation results show that the steering economy can be optimized by the collaborative optimization, and that the system can get good steering road feel, good steering flexibility and good mechanic character of the steering sensors.

The influence of various grease compositions and silver nanoparticle additives on electrically induced rolling-element bearing damage

Leakage currents accelerate surface degradation of metal contacts via small scale arcing across lubricating films,but recent observations suggest that metallic nanoparticle additives in lubricants may be useful to improve contact performance.These findings prompted a study that examined electrically induced surface pitting of steel contacts in the presence of several lubricating greases including some containing nanometer-sized colloidal silver(Ag)particles.Reciprocating rolling sphere-on-disk experiments were conducted under electro-tribological loads employing polyurea greases derived from mineral and synthetic base oils with and without additives.Friction forces and electrical resistance were monitored continuously during the tests;surface changes were characterized by means of optical spectroscopy,stylus profilometry,and scanning electron microscopy(SEM)including compositional analysis using energy dispersive spectroscopy(EDS).The observations demonstrate that surface pitting induced by arcing occurs mainly at the points were the rolling motion changes direction and that eroded metal is deposited along the wear grove.Micron-sized pits are formed which contain carbon and oxygen indicating that arcing causes decomposition of the hydrocarbon lubricants.Numerous findings indicate a significant inhibition of pitting is induced by the Ag nanoparticles;some greases containing other additives exhibit a similar,although less pronounced,effect.

轮毂电机温度场与水冷散热分析

由于轮毂电机发热率较高,散热性能较差,电机温度过高会降低电机工作效率以及影响电机工作稳定性。本文利用Maxwell软件建立的轮毂电机电磁仿真模型得出了电机相应的热源损耗;通过温度场计算模型计算了电机各部件的生热率以及电机重要表面的换热系数;设计了一种冷却电机的双螺旋冷却通道结构,利用Ansys软件对电机温度场及冷却结构进行了模拟,分析了冷却前和冷却后的温度场分布。结果表明,该冷却结构能大幅度降低电机工作时产生的温升影响,相较于传统单水道结构,双水道结构冷却效果更佳,对轮毂电机散热系统研究具有一定的参考价值。

基于计算流体力学冷却风机性能参数设计分析

冷却风机作为电动轮车辆轮边牵引电机冷却系统最重要的部件,其性能优劣对冷却系统的效果有直接的影响。针对强制冷却系统的结构特点,结合牵引电机的冷却需求,对影响风机冷却风量和压差的关键参数进行设计;在此基础上,基于CFD搭建风机的流场分析模型;采用差异化网格划分技术,对不同区域选取不同网格尺寸;对整机和叶片静压场进行分析,并对整机全压场和流道区域速度场进行分析,获取关键参数值,并与设计值进行对比。结果可知:风机内部的流场十分复杂,多处存在二次流和尾流-射流现象,但是流动趋势符合流体力学原理;模拟所得流量结果为3.86m^(3)/s与设计流量4m^(3)/s误差为3.63%,模拟功率结果为29.4kW与设计功率29.92kW的误差为1.77%,二者结果一致,表明设计和分析结果是合理的。参数设计计算和流场分析结果一致性,为同类型冷却风机设计提供参考。

面向经济性最优的电动汽车转矩动态分配策略研究

为了提高四驱电动汽车的整车能效,提出了根据电机系统效率最优法进行前后电机转矩动态分配的策略。在Cruise中建立了整车仿真模型,在Simulink中搭建了转矩分配策略模型,通过联合仿真计算了不同车速、不同轮端转矩下的前后电机转矩分配与电耗。通过对多种转矩分配策略计算结果的对比分析以及对试验车辆在测试场地的实测数据与仿真结果的对比分析,证明了所提出的转矩动态分配策略是可行的。另外,探讨了四驱车型在低转矩阶段采用脱开装置之后,电机效率提高和整车电耗降低的可行性。

矿用卡车MT5500电动轮典型故障分析及检修工艺优化

介绍了MT5500矿用卡车电动轮装配工艺的改进和密封设计的优化,旨在解决牵引电机压盖螺栓断裂和漏油故障问题;通过调整装配工艺和改进密封设计,提高了电动轮的使用寿命,降低了配件更换频率和检修工时。应用表明:新工艺的应用不仅提高了卡车的出动率,还降低了维修的劳动强度。

道路交通事故车辆类型司法鉴定实践

随着我国经济的快速发展,交通通行的需求快速增加,用于上下班通勤及短距离运输及载客的需求尤为显著。两轮电动车、三轮电动车、四轮电动车、两轮燃油车、三轮燃油车等轮式车辆随处可见。交通事故发生后,涉案车辆是机动车还是非机动车,在道路交通事故责任认定中至关重要。文章以实际鉴定工作为背景,结合具体案例,具体分析鉴定工作中常见的两轮、三轮及四轮车属于机动车还是非机动车,旨在帮助解决交通事故处理中各方对车辆属性(类型)的不理解。