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.

Steering Control of Wheeled Armored Vehicle with Brushless DC Motor

Considering the steering characters of one type of wheeled armored vehicle, a brushless direct current （DC） motor is adapted as the actuator for steering control. After investigating the known algorithms, one kind of algorithm, which combines the fuzzy logic control with the self-adapting PID control and the startup and pre-hrake control, is put forward. Then a test-bed is constructed, and an experiment is conducted. The result of experiment confirms the validity of this algorithm in steering control of wheeled armored vehicle with brushless DC motor.

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.

Blended Regenerative Anti-Lock Braking System and Electronic Wedge Brake Coordinate Control Ensuring Maximal Energy Recovery and Stability of All-Wheel-Motor-Drive Electric Vehicles

ABS is an active safety system which showed a valuable contribution to vehicle safety and stability since it was first introduced. Recently, EVs with in-wheel-motors have drawn increasing attention owing to their greatest advantages. Wheels torques are precisely and swiftly controlled thanks to electric motors and their advanced driving techniques. In this paper, a regenerative-ABS control RABS is proposed for all-in-wheel-motors-drive EVs. The RABS is realized as a pure electronic braking system called brake-by-wire. A coordination strategy is suggested to control RABS compromising three layers. First, wheels slip control takes place, and braking torque is calculated in the higher layer. In the coordinate interlayer, torque is allocated between actuators ensuring maximal energy recovery and vehicle stability. While in the lower layer, actuator control is performed. The RABS effectiveness is validated on a 3-DOF EVSimulink model through two straight-line braking manoeuvres with low and high initial speeds of 50 km/h and 150 km/h, respectively. Both regular and emergency braking manoeuvres are considered with ABS enabled and disabled for comparison. Simulation results showed the high performance of the proposed RABS control in terms of vehicle stability, brake response, stopping distance, and battery re-charging.

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.

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.

基于MPC的轮毂电机驱动车辆轨迹跟踪控制

为解决轮毂电机驱动车辆在复杂工况下轨迹跟踪精度低、横摆稳定性差的问题,提出一种协调控制方法。通过神经网络动态辨识以车辆质心侧偏角-质心侧偏角速度相平面划分的稳定域边界,并基于边界线特征值得出失稳因子;将该因子作为目标函数权重影响参数,构建轨迹跟踪MPC模型,输出前轮转角和四轮力矩控制量,同时,采用滑模控制方法防止车轮过度滑转。仿真表明,该轨迹跟踪控制策略与单目标MPC轨迹跟踪控制策略相比,在低附着路面车辆最大横向跟踪误差降低了61.7%,最大质心侧偏角降低了75.7%,车辆高速行驶时,运动状态均保持在稳定域范围内,实现了轨迹跟踪精度与车辆横摆稳定性能的综合提升。

FSEC赛车轮边行星齿轮减速器的设计与优化

为了提高中国大学生电动方程式大赛(FSEC)赛车在急加速及过弯时,极限工况条件下的传动效率,文章介绍了轮边减速器系统及其工作原理,对系统各项设计参数进行了具体的研究计算,简要描述了系统零件的研究设计及ANSYS静力学仿真分析的过程。研究结果表明,轮边行星齿轮减速器运行稳定可靠、装配方便,整体质量相对于其他传动方式较轻,传动效率较高;该系统将装配在辽宁工业大学万得电车队10号赛车上,以实际验证其设计合理性。研究结果可为后续赛车的轮边系统设计提供参考,以提高赛车的传动效率,满足赛车的轻量化要求,提高赛车性能。

Wireless Head Gesture Controlled Robotic Wheel Chair for Physically Disable Persons

A robotic wheelchair is assumed to be capable of doing tasks like navigation, obstacle detection, etc. using sensors and intelligence. The initial part of the work was development of a cap controlled wheelchair to test and verify the gesture operation. Following that, a real time operating wheelchair was developed consisting of mode changing option between joystick control mode and head gesture control mode as per as the user’s requirement. The wheelchair consists of MPU6050 sensor, joystick module, RF module, battery, dc motor, toggle switch and Arduino. The movement of the head is detected by MPU6050 and the signal is transmitted to the microcontroller. Then the signal is processed by controller and motion of wheelchair is enabled for navigation. The wheelchair was capable of moving left, right, forward and backward direction. The speed of the wheelchair was 4.8 km/h when tested. Design objective of the wheelchair included cost effectiveness without compromising safety, flexibility and mobility for the users.

Interaction of subway LIM vehicle with ballasted track in polygonal wheel wear development

This paper develops a coupled dynamics model for a linear induction motor （LIM） vehicle and a subway track to investigate the influence of polygonal wheels of the vehicle on the dynamic behavior of the system. In the model, the vehicle is modeled as a multi-body system with 35 degrees of freedom. A Timoshenko beam is used to model the rails which are discretely supported by sleepers. The sleepers are modeled as rigid bodies with their vertical, lateral, and rolling motions being considered. In order to simulate the vehicle running along the track, a moving sleeper support model is introduced to simulate the excitation by the discrete sleeper supporters, in which the sleepers are assumed to move backward at a constant speed that is the same as the train speed. The Hertzian contact theory and the Shen– Hedrick–Elkins’ model are utilized to deal with the normal dynamic forces and the tangential forces between wheels and rails, respectively. In order to better characterize the linear metro system （LMS）, Euler beam theory based on modal superposition method is used to model LIM and RP. The vertical electric magnetic force and the lateral restoring force between the LIM and RP are also taken into consideration. The former has gap-varying nonlinear characteristics, whilst the latter is considered as a constant restoring force of 1 kN. The numerical analysis considers the effect of the excitation due to polygonal wheels on the dynamic behavior of the system at different wear stages, in which the used data regarding the polygonal wear on the wheel tread are directly measured at the subway site.

MK3-15 Wagon Wheel便携式钻机在中东地区的应用与改进

本文介绍了MK3-15 Wagon Wheel便携式钻机的原理、功能及在中东地区山地钻井作业中的应用情况,对该钻机气动马达容易损坏的原因进行了分析,给出了相应的改进方法。

Electric Drive for an In-wheel Fractional-slot Axial Flux Machine

This paper describes the electric drive for an in-wheel fractional-slot axial flux machine,designed for achieving a wide flux-weakening operating region.By using a slotted stator with fractional-slot windings and additional cores enclosing end windings,the axial flux machine reaches a wide constant power speed range.The machine is designed for increasing flux-weakening capability while obtaining low harmonic back-electromotive force and low cogging torque.A 10 N.m axial flux machine exhibiting 3 to 1 flux-weakening speed range has been built.A flux-weakening controller,able to maximize the output torque in the flux-weakening region,is designed and implemented.The goodness of both design and control algorithm is proved by experimental tests.However,such a fractional-slot machine has not only advantages.Rotor losses are very high,and they have to be properly considered during the design process.

基于状态估计的轮毂电机驱动控制策略研究

为克服轮毂电机响应慢,控制精度和抗干扰性差的难题,本文在滑模控制(Sliding mode control,SMC)的基础上,开发基于转速和角度在线状态估计的超螺旋滑模(Super-twisting sliding mode control,STSMC)轮毂电机转速转矩联合控制策略。采用单移线工况,轮毂电机汽车匀速换变道时分别对各轮毂电机进行转速控制,满足阿克曼转向要求,变道后采用正弦过渡方法对各轮毂电机进行转矩控制,电机快速平滑输出期望转矩,车辆直线加速。为防止转速和角度传感器误差或者损坏,轮毂电机控制中采用最大相关熵平方根广义高阶容积卡尔曼算法(Maximum correlation entropy square root generalized high-order cubature Kalman filter,MCSRGHCKF)对转速和转子角度进行无传感器估计,实验测试得到转子角度估计误差为-0.05 rad,转速误差为0.3 r/min,满足电机控制要求。从电机启动到匀速运行阶段采用STSMC算法控制,转速超调量为6.33%,最大输出转矩为0.35 N·m,响应时间为0.22 s,稳态转速脉动为±0.5 r/min,转矩脉动为±0.01 N·m,相比PID和SMC算法,控制效果更佳。在转速切换转矩控制,转矩可按照正弦函数平滑过渡,最大超调仅为2.86%,电机运行平稳。

以谐波为导向的轮辐式磁场调制永磁轮毂电机转速波动抑制研究

结合车辆轮毂直驱应用场合需求,以“低速大转矩”能力出色的轮辐式磁场调制永磁轮毂电机为研究对象,系统性开展以谐波为导向的电机转速波动抑制研究。分析齿槽转矩这一引起电机转矩波动的重要因素,确定与之相关联的主导谐波阶次。并且,将关联谐波作为优化设计目标,有效削弱齿槽转矩,从而有助于在电机设计层面实现电机转速波动的抑制。此外,面临轮毂直驱场合复杂工况及恶劣路况的驱动需求,在电机控制层引入“扰动抑制能力出色”的自抗扰控制技术,在自抗扰控制器误差反馈控制律中针对性引入电机齿槽转矩主导谐波的抑制环节,提出谐波导向型线性状态误差反馈控制律,进一步抑制了电机的转速波动。理论分析与实验结果验证了研究的合理性。

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。

基于主动后轮转向的车辆稳定性控制策略

为实现四轮轮毂电机驱动车辆的操纵稳定性控制,提出了主动后轮转向和附加横摆力矩复合控制策略。针对高速行驶转向灵敏度大的问题,对前后轮转向比进行优化。策略采用分层式控制框架,上层基于线性时变模型预测控制算法,建立了四轮轮毂驱动车辆时变预测模型,推导和跟踪包含后轮转向系统的理想输出轨迹,并计算了跟踪理想状态轨迹所需附加力和力矩。下层通过求解四轮转矩分配优化问题,实现了滑移率阈值控制,解决了再生制动和机械制动的分配问题。仿真结果表明,提出的复合控制策略能够达到预期控制效果,改良了车辆横纵向稳定性。

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。

聚磁式永磁轮毂电机多目标优化设计

集成二级行星减速器轮毂驱动系统对电机电磁和力学性能提出了更苛刻需求。为进一步提升永磁轮毂电机转矩密度和弱磁范围,提出一种聚磁式永磁轮毂电机拓扑结构,分析转子关键参数对转矩密度、弱磁能力和转子强度的影响规律,确定电机初始优化目标;进一步利用有限元及响应面法构建输出转矩、特征电流及转子应力的代理优化模型,并利用改进布谷鸟算法进行多目标优化设计;对比分析优化前后电机电磁和机械性能。最后,试制75 kW聚磁式永磁轮毂电机,试验结果验证所提多目标优化算法的可行性和有效性。

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。