线控转向系统变角传动比设计及路感模拟

变角传动比设计及路感模拟是线控转向系统的核心部分。根据车辆的转向灵敏度和车速确定了变角传动比的设计方案。通过分析不同路感模拟的策略,考虑到“人-车-路”闭环系统各个环节间的相互关系,并结合不同驾驶员的偏好与转向系统对道路信息的反馈,基于权重法进行转向路感的模拟。通过Carsim/Simulink仿真双移线和双纽线工况,结果表明该转向系统不但减轻了驾驶员操作负担,而且还兼顾了驾驶员的偏好,并且能够及时响应道路变化,提高了车辆的操纵稳定性和转向轻便性。     

Experimental validation of steering torque feedback simulator through vehicle running test

This paper describes a force feedback system based on real-time multibody dynamic analysis. This system can provide the analyzed reactive force to the operator through the operational device. In this study, this system is used as a steering torque feedback simulator of an automobile. This simulator can provide the haptic sensation of the steering wheel to the operator. For the purpose of evaluating the validity of the developed simulator, we conducted some vehicle running tests with an experimental electric vehicle. The results of these tests were compared with the results simulated on the steering torque feedback simulator. It was shown that the developed simulator can provide a suitable steering torque to the operator. This paper was presented at the 4th Asian Conference on Multibody Dynamics(ACMD2008), Jeju, Korea, August 20–23, 2008. Dr. Taichi Shiiba received a Doctor of Engineering from The University of Tokyo in 2001. He became an Associate Professor at Meiji University in 2007. A Member of JSME and JSAE, his major areas are multibody dynamics, vehicle dynamics, and driving simulators. Wataru Murata received a B.S. degree in mechanical engineering from Meiji University in 2007. His research interests are vehicle dynamics, real-time analysis, and multibody dynamics.     

Improvement of the steering feel of an electric power steering system by torque map modification

This paper discusses a de motor equipped electric power steering (EPS) system and demonstrates its advantages over a typical hydraulic power steering (HPS) system The tire-road interaction torque at the steering tires is calculated using the 2 d o f bicycle model, in other words by using a single-track model, which was verified with the J-turn test of a real vehicle Because the detail parameters of a steering system are not easily acquired, a simple system is modeled here In previous EPS systems, the assisting torque for the measured driving torque is developed as a boost curve similar to that of the HPS system To improve steering stiffness and return-ability of the steering system, a third-order polynomial as a torque map is introduced and modified within the preferred driving torques researched by Bertollini Using the torque map modification sufficiently improves the EPS system     

STEERING SAFETY EVALUATION OF DRIVER-VEHICLE CLOSED-LOOP SYSTEM WITH RANDOM ROAD INPUT

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电动助力转向的转向感觉客观综合评价

针对电动助力转向(Electric power steering,EPS)系统进行整车转向感觉主观评价试验,分别对转向轻便性、回正性、中间位置转向和移线性能转向感觉客观评价指标进行分析。由于单个指标与驾驶员整体转向感觉评价之间并没有直接的对应关系。通过主成分分析的方法,获得互不相关的客观综合评价指标,将主观转向感觉量化为客观评价指标值,并且对客观评价指标与驾驶员主观评价进行相关性检验,检验EPS转向感觉客观评价指标的合理性和可靠性。转向感觉客观评价指标的确定便于对EPS转向感觉进行系统全面的评定,提高设计的可预见性。     

人体模块撞击汽车转向机构数值模拟与试验分析

根据国家标准《防止汽车转向机构对驾驶员伤害的规定》,人体模块以 2 4.1km/ h～ 2 5 .3 km/ h的速度水平撞击转向盘时 ,作用在转向盘上的水平力不得大于 1112 3 N。本文按国家标准建立了人体模块与某车型的转向机构有限元模型 ,并对试验过程进行数值模拟分析 ,仿真结果与试验结果吻合。因此 ,利用仿真技术对评价汽车转向机构碰撞安全性具有一定借鉴意义     

汽车ESC系统DIL/HIL仿真平台设计

全面准确地标定与测试是开发车辆电子稳定控制(electronic stability control,ESC)系统的关键环节。车辆控制过程是典型的强非线性系统,建立精确的车辆模型比较困难,驾驶员模型也很难准确模拟紧急工况下驾驶员的真实反应。在仿真系统中将难以精确建模的液压制动系统、ESC压力调节单元、转向及电子节气门装置采用真实硬件,并在试验平台中嵌入真实驾驶员,基于Matlab/Simulink/dSPACE环境和车辆动力学软件veDYNA,开发硬件在环(hardware-in-the-loop,HIL)和驾驶员在环(driver-in-the-loop,DIL)的仿真试验平台,并在此平台上对所设计的ESC系统进行仿真试验研究。试验结果表明,所设计的DIL/HIL仿真平台可以大幅提高ESC系统的开发效率和测试准确性。     

沙滩车电动助力转向系统故障诊断分析研究

为了更好的研究沙滩车电动助力转向系统,分析了沙滩车电动助力转向控制系统结构,控制策略采用PID控制算法。故障诊断是沙滩车行车安全的重要保障,因此结合故障树对故障诊断进行了详细分析研究,对不同的故障采用了不同的故障处理方法。用实车测试数据对控制策略及故障诊断进行了验证分析,分析结果表明,所研究的沙滩车控制方法达到了设计要求。     

HUMAN-SIMULATING VEHICLE STEERING CONTROL ALGORITHM

A new vehicle steering control algorithm is presented. Unlike the traditional methods do, the algorithm uses a sigmoid function to describe the principle of the human driver's steering strategy. Based on this function, a human simulating vehicle steering model, human-simulating steering control(HS) algorithm is designed. In order to improve the adaptability to different environments, a parameter adaptive adjustment algorithm is presented. This algorithm can online modify the value of the key parameters of the HS real time. HS controller is used on a vehicle equipped with computer vision system and computer controlled steering actuator system, the result from the automatic vehicle steering experiment shows that the HS algorithm gives good performance at different speed, even at the maximum speed of 172 km/h.     

轮毂电机独立驱动电动汽车差速转向路感控制研究

为改善电动轮汽车差速转向系统的转向路感,建立了电动轮汽车差速转向和整车系统的动力学模型。基于鲁棒控制理论,在保证H∞性能的前提下,设计了系统PID控制器,并进行了仿真分析。结果表明,基于H∞-PID控制的差速转向系统可在满足系统H∞鲁棒性能的基础上,进一步减小系统的静态误差,提高差速转向路感系统的灵敏度和系统精度,使驾驶员获得更为满意的转向路感。     

某汽车转向液压系统故障分析与改进

汽车动力转向系统是保证车辆安全行驶的重要系统,该系统为双回路液压系统,主要由分配阀、转向器、转向油箱、溢流阀、精滤器等组成。针对某型号车辆频繁出现的转向器故障,分析了转向系统的工作原理,并深入剖析了加在转向器上的力矩变化规律,找出了动力转向液压系统中转向器频繁损坏的原因,指出了该系统的不足,并提出了相应的改进措施。     

浅谈汽车的转向系统

转向系统是任何车辆都不可或缺的组成部分,其设计制造质量的优劣直接关系到车辆的操纵稳定性、安全性等技术性能。笔者阐述了汽车转向系统技术发展的状况,指出了各种转向系统的结构特点、工作原理及优缺点,并展望了汽车转向系统未来的发展方向。     

运动副间隙对汽车摆振系统非线性动力学行为影响分析

在前期研究中发现运动副间隙对机构的动力学响应影响显著,因此做出转向系统中的间隙也会对转向摆振系统的响应产生重要影响的推断。为此,将转向梯形机构简化为一个连杆机构,并就机构中运动副间隙对转向系统摆振的影响进行了分析。借助拉格朗日方程建立考虑转向机构运动副间隙的6自由度转向系统摆振动力学模型,基于该摆振模型,应用四阶龙格－库塔法对间隙参数发生变化时摆振系统的响应进行仿真分析。通过仿真分析结果发现：转向机构运动副间隙是诱发转向轮摆振系统混沌运动的重要因素,在摆振系统建模过程中应予以充分考虑;随着运动副间隙增大,转向摆振系统会由周期运动状态经过拟周期运动状态逐渐进入混沌状态,造成摆振运动加剧。相关结论可为转向系统摆振的有效控制奠定理论基础。     

Active disturbance rejection control in steering by wire haptic systems

This paper introduces a steering by wired haptic system based on disturbance rejection control techniques. High gain Generalized Proportional Integral (GPI) observers are considered for the estimation of tire and steering wheel dynamic disturbances. These disturbances are on line canceled to ensure tracking between the commanded steering wheel angle and the tire orientation angle. The estimated disturbances at the steering rack are feedback to the steering wheel to provide a haptic interface with the driver. The overall system behaves as a bilateral master-slave system. Very few sensors and minimum knowledge of the dynamic model are required. Experimental results are presented on a prototype platform that consists on: (1) half of the steering rack of a beetle VW vehicle, (2) a steering wheel.     

无人驾驶车辆路径跟踪控制预瞄距离自适应优化

基于道路信息,使用驾驶员预瞄模型产生执行器输入是无人驾驶车辆在路径跟踪中使用的主要方法之一,但对于车速较高与转弯半径小等工况,模型误差会导致较差的驾驶舒适性,车辆甚至失去稳定性。为提高无人驾驶车辆路径的跟踪精度,同时兼顾转向频度和车辆稳定性,提出基于粒子群多目标优化（Particle swarm optimization,PSO）算法的预瞄距离自适应驾驶员模型,并将之应用于路径跟踪控制。首先,基于单点预瞄偏差模型,采用滑模变结构设计转向控制器;其次,以路径跟踪精度、转向频度和车辆稳定性为综合性能指标,设计了PSO优化算法,实现了驾驶员模型预瞄距离的自适应寻优。最后,在搭建的CarSim-Simulink联合仿真平台与台架试验上,对所提出的预瞄距离自适应驾驶员预瞄模型进行了仿真和硬件在环试验验证。结果表明,经优化后的预瞄距离能够适应不同车速和道路曲率,驾驶员预瞄模型能兼顾路径跟踪精度、转向频度和车辆稳定性等需求。预瞄距离自适应驾驶员模型结合道路与车速信息,增大对路况与车况适应性,为无人驾驶车辆路径跟踪控制提供可靠的输入。     

人-车闭环中电动助力转向系统的基本特性分析

建立详细的四自由度电动助力转向(EPS)系统机械电气模型,考虑Fiala轮胎模型和二自由度整车模型,引入以转向盘输入角为反馈信号的驾驶员模型,构建装备EPS系统的人-车非线性闭环系统模型。采用模糊控制器确定目标电流并通过PID控制和脉冲宽度调制(PWM)实现其跟踪控制,构建电流闭环控制,并采用基于非线性控制设计(NCD)的单纯形自寻优法对参数进行优化。通过仿真计算,以转向盘输入转矩以及整车的横摆角速度、侧向加速度为指标,研究分析了EPS系统在人-车非线性闭环系统中的基本特性。     

线控转向车辆转向盘转矩特性研究

车辆线控转向系统取消了转向盘与转向轮之间的部分机械连接,车辆转向阻力矩无法直接反馈给驾驶员。从驾驶员偏好转向盘转矩的角度出发,在分析转向盘转矩影响因素的基础之上,提出一种考虑摩擦力矩、阻尼控制力矩、限位控制力矩以及主动回正力矩的线控转向系统转向盘转矩的模型,并通过试验数据对模型中的参数进行辨识。选取双纽线试验和中心区特性试验等进行仿真分析和硬件在环验证。结果表明,所建立的转向盘转矩模型能够保证低速时的转向轻便和高速时的路感清晰,并且很好地描述了车辆在不同行驶工况下的转向盘转矩特性,充分发挥了线控转向车辆转向盘转矩可以根据驾驶员需求自由设计的优势。     

Variable structure controller design for steer-by-wire system of a passenger car

The electric power steering (EPS) system was developed and the steer-by-wire (SBW) system achieves the purposes of EPS. The advantages of SBW are packaging flexibility, advanced vehicle control system, and superior performance. No mechanical linkage exists between the steering gear and steering column in the SBW system. The steering wheel and front-wheel steering can be controlled independently. The SBW system consists of two motors controlled by an electronic control unit (ECU). One motor is in the steering wheel and develops the steering feel of the driver and the other motor is in the steering linkage and improves vehicle maneuverability and stability. Moreover, the active front steering (AFS) system can be added to the SBW system. AFS reduces the difference between actual and estimated vehicle yaw rate. Up-to-date information from the steering wheel enables drivers to identify road conditions through the tire force, which should be fed back to the steering wheel. Furthermore, several control algorithms related to the vehicle and motor can be used together through the self-aligning torque, which is fed back to the steering wheel. This study proposes a method to control the vehicle yaw rate through an SBW system. This control method is based on a PID control method for the steering-wheel-motor controller, as well as on a sliding mode control (SMC) method for the front-wheel-motor controller and yaw stability controller. The SBW system is modeled using a bond graph method. Results imply that the controllers are robust enough when in contact with nonlinear properties of tire and road conditions. This study is expected to guide further research on the SBW system.     

一种简化辅助泊车模型的建立与仿真研究

通过简化运动与转向过程中的车辆以及停车位,提取出车辆以及停车位的主要参数,建立了一种基于运动学及转向模型的两阶段简化辅助泊车模型。应用该模型在MATLAB中进行模拟泊车分析,模拟计算结果与实车泊车入位过程一致性较好,该模型可推广应用于实车泊车系统没计。     

汽车移线轨迹的闭环最速控制模型及仿真

提出了汽车驾驶员移线控制的时间最小模型，该模型是考虑自动操纵汽车时常常采用的达到某一目标所需时间最小的原则，进一步采用闭环反馈开关控制进行轨迹拟合和优化控制，确定出最优轨迹和最优操纵时刻，称为最速控制。采用仿真方法验证了该模型及最速控制理论和方法的正确性，该理论和方法不仅可以作为智能汽车或汽车自动驾驶的控制方法，也可以作为一种驾驶员模型为汽车转向系统的合理设计提出方向。