Lateral stabilization of a four wheel independent drive electric vehicle on slippery roads

In this paper, a new controller is proposed for lateral stabilization of four wheel independent drive electric vehicles without mechanical differential. The proposed controller has three levels including high, medium and low control levels. Desired vehicle dynamics such as reference longitudinal speed and reference yaw rate are determined by higher level of controller. Moreover, using a neural network observer and a fuzzy logic controller, a novel reference longitudinal speed generator system is presented. This system guarantees the vehicle’s stable motion on the slippery roads. In this paper, a new sliding mode controller is proposed and its stability is proved by Lyapunov stability theorem. This sliding mode control structure is faster, more accurate, more robust, and with smaller chattering than classic sliding mode controller. Based on the proposed sliding mode controller, the medium control level is designed to determine the desired traction force and yaw moment. Therefore, suitable wheel forces are calculated. Finally, the effectiveness of the introduced controller is investigated through conducted simulations in CARSIM and MATLAB software environments.     

Parametric design and application of steering characteristic curve in control for electric power steering

Electric power steering (EPS) is considered as the future of power assisted steering technology for passenger cars. In this paper the authors study the process of how to design the steering characteristic curve, analyze the steering characteristic curve using the driver’s steering feel, and proposes a power sinusoidal steering curve, which is parametric and can be altered easily in the prototype tests. Furthermore the authors study the detecting process of steering torque sensor in EPS control systems, and distinguish between actual steering torque and an ideal one. Using this way the authors deduce a formula to calculate the reference torque, which is based on the variation of the system loads. Finally, experimental results on certain vehicles have indicated the feasibility of the adjustable parameters and the effectiveness of the deduced formula.     

基于PLC控制技术和气压传动控制技术的汽车前悬架与转向轮螺纹装配设备研发

在装配汽车前悬架与转向轮时需要拧紧螺纹,一旦操作不当就会出现前倾角过大的缺陷,加快车轮胎的磨损,降低小轴承及轮毂紧固螺母的使用寿命。对此,本文设计了一种基于PLC控制技术和气压传动控制技术的装配设备,能有效避免上述问题。     

基于模糊自适应的智能车驱动与转向协同控制研究

为改善智能车驱动电机调速与舵机转向的协调性,简化调参适配步骤,提出了基于MK60FN1(MK60)芯片的驱动与转向协同控制的模糊自适应控制方案。MK60计算出摄像头拍摄图像中车体与车道中线的位置偏差和角度偏差,根据位置偏差与舵机角度、角度偏差与测量到的车速,采用局部参数优化理论设计模糊自适应控制算法实时调整驱动电机和舵机的可调增益实现协同控制。与驱动、转向分开独立控制的策略相比较,本方案减小了稳态误差,智能车能够更快完成自主循迹,稳定性更好。     

电液控制四轮转向技术在电动搬运车中的应用研究

电液控制四轮转向技术是一种主要应用于工程车辆领域的智能控制技术,利用电液比例阀技术控制四组车轮同步转向的系统.电液四轮转向系统结合了液压系统独有的高扭矩特性以及四轮独立转向带来的小转弯半径特性,很好的解决了大吨位工程搬运车辆在狭小空间内搬运货物的难题.系统对主要部分进行建模仿真分析,验证了电液控制四轮转向技术的良好性能.     

基于AVR的纯电动车无刷直流电机驱动系统

根据整车参数要求。设计一种基于AVR单片机控制的纯电动汽车无刷直流电机驱动系统。该系统以MEGA48单片机作为控制芯片．进行了电源电路设计、系统硬件保护电路设计、三相全桥逆变电路设计、逆变器驱动电路设计,利用PI控制器进行电机电流速度的双闭环控制,并采用C语言进行模块化编程和结构化编程。该系统可以实现欠压、过流和堵转保护。在系统出错情况下具有自检功能,同时具有升级空间,便于用户二次开发。     

基于模糊控制的电动汽车再生制动系统的研究

再生制动能够降低能源的消耗量和延长电动汽车的行驶里程。它广泛的受到诸多学者的关注。本文提出了一个新颖的再生制动控制系统。该系统基于无刷直流电机的控制特性和电动汽车刹车时的制动特性,直流无刷电机采用传统的PID控制,刹车力采用模糊逻辑控制,刹车力矩可以由PID控制器实时的控制。通过Matlab/Simulink软件,仿真分析了电池的充电状态、制动力和直流侧线电流。实验和仿真结果均证实了在具有良好的刹车性能的前提下,该方法可以实现良好的再生制动性能和延长电动汽车的行驶里程,在工程上更加易于实现也具有更好的鲁棒性和更高的效率。     

Experimental analysis on autoresonant control of ultrasonically assisted drilling

The target of this paper is to employ autoresonant control technique to maintain the nonlinear oscillating mode at resonance (ultrasonic vibration at the tip of a drill bit at a desired level) during vibro-impact process. In order to achieve this, an autoresonant control system which intends to provide the possibility of self-tuning and self-adaptation mechanism for an ultrasonic vibrating system to maintain the resonant regime of oscillations automatically by means of positive feedback was developed and manufactured. The autoresonant control system was implemented through a ‘controlled variable’ transformation and amplification. Three feedback control strategies were employed depending on the attributes of the ‘manipulated variables’. Mechanical feedback control uses the displacement signal at the end of an ultrasonic transducer. The other two control strategies are current feedback control and power feedback control. The current feedback control employs the current flowing through the piezoceramic rings as the ‘controlled variable’ while power feedback control takes into account both current and power of an ultrasonic vibrating system.In order to investigate the tool effect on the established autoresonant control system, two sizes of drill bits with diameters 3 mm and 6 mm were employed in combination with three autoresonant control strategies. These were executed in drilling aluminium alloys 1050 with hardness 45 HV with a fixed rotational speed combined with several feed rates. Controlled variables, responding variables, feed force reduction were monitored. Holes quality and surface finish examinations supplement the analysis of the efficiency of the control systems.     

工业运输电动车往返自动控制系统设计

本文介绍继电控制系统在工业运输电动车中综合应用的基本工作原理,通过继电控制系统控制电动机供电线路,实现电机正转、反转、停机,从而达到了电动车正向、反向运行和随时停车的目的。该系统设计简单,适合控制往返重复运动的工业运输电动车,并且能降低工业生产成本,有效提高生产效率。     

基于ESO磁链观测器的直接转矩控制的研究

讨论直接转矩控制方法在永磁同步电机中的应用问题,利用MATLAB仿真工具对永磁同步电机直接转矩控制系统仿真。针对直接转矩控制低速时存在较大转矩脉动的问题,采用观测器方法克服传统磁链模型中参数的不确定性对磁链观测精度的影响,保证全速范围内磁链的准确估计,提高控制性能。仿真表明观测磁链具有较高的精度,对电阻的不确定变化具有较强的鲁棒性,并可准确估计无速度传感器的速度及位置。     

An adaptive hierarchical control approach of vehicle handling stability improvement based on Steer-by-Wire Systems

This paper proposes a novel adaptive hierarchical control approach for Steer-by-Wire (SbW) vehicles to improve the handling stability. The high-level stability control scheme contains a variable steering ratio (VSR) strategy based on the adaptive-network-based fuzzy inference system (ANFIS) and an active front steering (AFS) controller designed with the integral sliding mode method by tracking the expected yaw rate, in which the desired front wheel angle is generated to enhance the cornering stability performance. Besides, an adaptive tracking controller (ATC) for the SbW system is designed by using the adaptive sliding mode control method to achieve desired steering performance in the lower level. The proposed adaptive control strategy is validated with different driving circles from ISO standards in simulation tests and hardware-in-the-loop (HiL) experiments. The results demonstrate that the designed control approach improve the vehicle handling stability significantly, even in some extreme driving conditions.     

基于ESO磁链观测器的直接转矩控制的研究

讨论直接转矩控制方法在永磁同步电机中的应用问题,利用MATLAB仿真工具时永磁同步电机直接转矩控制系统仿真.针对直接转矩控制低速时存在较大转矩脉动的问题,采用观测器方法克服传统磁链模型中参数的不确定性对磁链观测精度的影响.保证全速范围内磁链的准确估计.提高控制性能.仿真表明观测磁链具有较高的精度,对电阻的不确定变化具有较强的鲁棒性.并可准确估计无速度传感器的速度及位置.     

音圈电机激光扫描器的线性扫描控制

建立了音圈电机驱动的激光扫描器的模型并进行了参数辨识。由于音圈电机驱动的激光扫描器反馈回路的高频噪声较大,利用光电精密跟踪的传统方法,如改进型PID控制算法,以及理想闭环特性(最佳二阶特性)的逆向设计方法,系统并不能稳定工作,易振荡。分析了造成振荡的原因,采用前馈复合控制方法,避开了振荡因子同时又减小了稳态误差,解决了稳态误差和振荡的矛盾。结合反馈回路噪声大的特点,将滤波器加入反馈回路中,使激光扫描器不仅能稳定工作,消除了扫描时候的抖动,同时减少了线性扫描时候的磁滞现象。     

电动客车用无刷直流电机控制系统仿真分析

针对电动客车提出了一种新的纯电动客车用无刷直流电机的系统建模方法,该无刷直流电机模型可以实现无刷直流电机的性能、同时可以实现无刷直流电机的过流、欠压及霍尔传感器缺相等故障保护的综合仿真,将此无刷直流电机模型应用于纯电动客车驱动系统。通过分析无刷直流电机数学模型和纯电动客车动力学方程,采用S函数和模块化建模方法,在Matlab7.0/Simulink环境下,建立了无刷直流电机驱动纯电动客车车速控制系统模型,并对该控制策略在某档位下进行了静、动态性能验证。仿真结果表明:车速调速策略具有超调小、响应速度快、鲁棒性好、自适应能力强等优点,同时验证了带有故障保护功能模型的有效性,为无刷直流电机驱动纯电动客车系统仿真提供了新的方法     

Numerical investigation of liquid cooling cold plate for power control unit in fuel cell vehicle

This paper proposed fifteen structure schemes of the liquid-cooled plate for thermal control of the power control unit (PCU) in fuel cell vehicle (FCV). At the given serpentine channel with inconstant width, pin fin arrays with various configurations were arranged to improve the performance of three heating zones with multiple heat sources. Based on the same setup and boundary conditions, numerical simulations were conducted for different schemes. The solutions were validated by grid independence check and comparison with previous researches. Effects of fin geometrical parameters (such as diameter, height, fin pitch and shape) on pressure drop and heat transfer characteristics were investigated. Furthermore, two dimensionless factors η_H and η_P were quantified to evaluate the heat transfer enhancement and pressure drop augmentation. The dimensionless performance evaluation factor P_EF was cited to assess overall performance of the cold plate. Based on three factors mentioned above, cooling performances of three heating zones and the whole plate were compared among all schemes. According to the performance comparison, scheme 12 employing circular fins with diameter of 4 mm was selected as the optimal solution for the cold plate.     

电流法在天线传动系统故障及跟踪性能分析中的应用

分析了天线传动系统影响电机电流特性的因素.提出了天线正常跟踪卫星的电流特性标准,电流在6 A以下属于正常范围.利用电机电流分析法,对测控天线传动系统的周期性故障、阻尼增大故障以及系统级故障进行定位判断,提出了产生故障的因素.同时,分析了上述三类故障对测控天线的跟踪性能的影响.结果表明,电机电流分析法可以对天线传动系统的...     

Modeling, identification, and real-time control of bucket hydraulic system for a wheel type loader earth moving equipment

>The earth moving equipment industry is quickly gearing up to achieve great gains in efficiency, performance, safety, and operator comfort by the rapid deployment of recent digital control technology in its products. There are two major types of earth moving equipment operating in large numbers: excavators and wheel type loaders. Excavators have received much attention by the industry recently. The wheel type loader product studied in this paper is another example of a high volume versatile machine at the opposite end of the configuration spectrum. A state of the art electro-hydraulic open centered non-pressure compensated valve control system is studied to evaluate the potential gains by implementing digital velocity servo control. The control objectives are to (1) meet operator perceived response requirements, (2) meet operator perceived smoothness requirements, (3) create a sub-system that could accept commands from an autonomous high level planning controller.

Closed loop digital velocity control is successfully implemented in the racking motion of a wheel loader using a standard proportional-integral (PI) and a dynamic valve transform algorithm. The dynamic valve transform is a function of hydraulic flow rate which is a function of engine speed and rod end cylinder pressure. Robustness of performance was verified through extensive system modeling, validation, and hardware tests on a large Caterpillar wheel loader model 990. © 1998 Published by Elsevier Science Ltd. All rights reserved.     

无人机扩频遥控链路Rake接收机设计

针对无人机起降阶段多径效应会引起遥控误码率性能下降的问题，提出了一种基于导频辅助的Rake抗多径算法。该算法通过在传输帧中插入导频符号和在遥控接收机中增加Rake抗多径模块的方式，使无人机遥控链路在多径信道下的误码率性能得到了显著改善。在高斯、莱斯、瑞利等信道条件下对算法进行了仿真，结果表明，该算法能够将无人机起降阶段的遥控误码率提高2～3个量级。实测数据进一步验证了该算法抗多径性能的有效性。