双十字轴万向节转向系统力矩波动的优化设计

汽车转向力是汽车操纵稳定性评价中的重要指标,转向力的力矩波动直接影响着驾驶感受,合理的相位角设计能够有效地减少力矩波动。本文阐述了转向系统力矩波动原理,并运用该方法进行了某车型转向系统的优化设计。     

汽车转向系统的力矩波动研究与优化

汽车转向力矩波动大会降低驾驶舒适性。为减少汽车转向力矩波动,本文以齿轮齿条式转向系统为研究对象,在尽可能减少原方案变更的前提下,应用三维建模软件CATIA建立转向系统的硬点结构模型;推导了力矩波动的原理公式,分析了影响转向力矩波动的重要因素;根据分析结果,分别设计了优化转向轴参数和优化转向机参数两种转向力矩控制方法,结果表明该两种方法均能使转向系统的力矩波动减小至1%以内,有效提升驾驶舒适性,保障驾乘安全。     

汽车转向系统力矩波动的匹配研究

转向力是汽车操纵稳定性评价中重要指标,其力矩波动直接影响着驾驶感觉,匹配正确的相位角能够有效地减少力矩波动。本文详细地阐明了汽车转向系统力矩波动原理。对某车型转向系统力矩波动情况进行匹配研究。     

位置可调转向管柱传动的运动学分析及应用

方向盘在前后伸缩或者上下角度调整之后,转向系统的不等速特性引起的力矩波动,方向盘幅角及转向管柱的摩擦力矩变化都会发生变化。通过建立局部坐标系,进行空间坐标转换,推导了输入轴和输出轴转角的关系式。使用该方法可以计算不同方向盘调节位置时转向管柱传动的不等速特性,转向管柱位置调节导致的方向盘幅角变化,转向管柱万向节的摩擦力矩变化。基于以上三个计算结果,提出了输出轴的初始相位的设定方法。     

基于ADAMS/View的汽车转向系统力矩波动优化设计

汽车转向过程中,转向力矩的波动直接影响驾驶员操作的舒适性和驾驶平顺性。文章在ADAMS/View中建立了参数化的汽车转向操纵系统双十字轴万向节传动运动学仿真优化分析模型,基于建立的仿真优化模型对某车型转向系统的力矩波动进行了仿真分析并进行了优化设计,得出了最佳的转向传动轴万向节叉的相位角及轴系布置方案,优化方案将转向系统的力矩波动控制在了允许的范围内,得到了满意的结果。     

基于MATLAB对转向力矩波动的应用研究

文章提出一种基于MATLAB数值分析方法,对汽车转向系统的力矩波动进行理论计算的思路和方法。并针对整车人机四向调节的转向管柱布置,能够较为准确的确定布置硬点。     

某微型纯电动车转向系统力矩波动优化改进

文章阐述了汽车转向系统的结构型式和转向力矩波动原理,并利用该原理,在某车型转向系统硬点不改变的情况下,确定转向系统的最佳中间轴相位角,使该车型转向系统力矩波动降到最低,并通过实车验证。     

双十字万向节式转向传动轴力矩波动研究

研究在轿车转向系统中,由于十字万向节的空间布置而产生的转向传动轴力矩波动问题。应用MATLAB建立数学模型,对力矩波动进行仿真及优化,仿真界面操作简单且易于使用。最后,对转向传动轴的空间布置提出了要求。     

汽车转向系统十字轴万向节传动优化设计

转向力是汽车操纵稳定性中一项重要的评价指标,其力矩波动直接影响驾驶感觉。文章对汽车转向轴的布置与力矩波动的关系进行了分析,并针对某车型转向系统的十字轴万向节结构进行优化设计。优化结果在matlab软件里仿真,得到较好的结果,波动力矩在允许的范围内。并得出最佳的中间轴相位角及轴系布置方案,对转向系统的优化设计有一定的参考价值,可作为实际车型开发中传动优化设计的技术依据。     

液压转向系统手力沉重原因及优化

在新车型开发过程中经常出现转向手力沉重的问题.通过原地转向手力矩测试,得到全行程沉重、末端沉重及波动沉重3种问题车型原地转向手力矩曲线.根据曲线走向,判定手力沉重的要因,从而实施验证方案解决转向沉重的问题.整改后的转向手力矩一般为4N·m,属于轻便型手感,满足一般用户驾驶需求.整改方案为液压转向系统手力沉重问题提供了解决思路,同时也为新车型开发提供了转向系统手力矩的设计方法.     

Torque ripple minimization control of permanent magnet synchronous motors for EPS applications

This paper identifies a control method used to reduce torque ripple of a permanent magnet synchronous motor (PMSM) for an electric power steering (EPS) system. NVH (Noise Vibration Harshness) is important for safe and convenient driving. Vibration caused by motor torque is a problem in column type EPS systems. Maintaining a very low torque ripple is one solution that allows for smoother steering. Theoretically, it is possible to design and drive the motor without torque ripple. However, in reality, a PMSM system torque ripple is caused by the motor itself (saturation in the iron core and EMF distortion) and the imperfect driver. This paper analyzes torque ripple of a PMSM system, and an advanced PMSM control method for the column typed EPS system is presented. Results of the analysis indicate that the compensation current is needed in order to minimize torque ripple when a PMSM is driven.     

基于驾驶员在环的EPS试验台开发

汽车转向系统性能与汽车的操纵稳定性和舒适性有关,对汽车的行驶安全起着至关重要的作用。随着动力转向系统的发展,电动助力转向系统的优势逐渐突出。这里运用七自由度汽车模型,拟设计出一种基于驾驶员在环的转向测试试验台,将驾驶员操纵的油门踏板和转向信号实时采集,通过信号运算和汽车动力学模型实时仿真,实现转向力矩的模拟和车辆状态信息的输出,并可以快速进行EPS系统的开发验证。     

Boundary conditions of active steering control of independent rotating wheelset based on hub motor and wheel rotating speed difference feedback

The source of torque ripple in a permanent-magnet synchronous motor was analysed. Based on the feedback of the rotating speed difference between the left and right wheels, the error value of torque ripple in an in-wheel motor was calculated. Next, a simulation model of active steering control of an independently rotating wheel (IRW) in an in-wheel motor was developed to investigate effects of torque ripple. The relationship between the accuracy of active steering control of an IRW in an in-wheel motor and wheel/rail profile was derived, and then the boundary conditions of active steering control were obtained. Finally, a method was proposed to improve the active steering control of an IRW by optimising the tread.     

基于计算机视觉的驾驶员转向操作实时监测研究

为实时监控驾驶员操纵转向盘的状态，构建了基于机器视觉汽车转向盘实时监控系统，并运用阈值分割和边缘检测方法对转向盘图像中感兴趣区域进行了图像分割，提出了转向盘转角的计算公式。试验结果表明，感兴趣区域图像分割与转向盘转角监测方法有效。     

Integrated fuzzy/optimal vehicle dynamic control

There are basically two methods to control yaw moment which is the most efficient way to improve vehicle stability and handling. The first method is indirect yaw moment control, which works based on control of the lateral tire force through steering angle control. It is mainly known as active steering control (ASC). Nowadays, the most practical approach to steering control is active front steering (AFS). The other method is direct yaw moment control (DYC), in which an unequal distribution of longitudinal tire forces (mainly braking forces) produces a compensating external yaw moment. It is well known that the AFS performance is limited in the non-linear vehicle handling region. On the other hand, in spite of a good performance of DYC in both the linear and non-linear vehicle handling regions, continued DYC activation could lead to uncomfortable driving conditions and an increase in the stopping distance in the case of emergency braking. It is recommended that DYC be used only in high-g critical maneuvers. In this paper, an integrated fuzzy/optimal AFS/DYC controller has been designed. The control system includes five individual optimal LQR control strategies; each one, has been designed for a specific driving condition. The strategies can cover low, medium, and high lateral acceleration maneuvers on high-μ or low-μ roads. A fuzzy blending logic also has been utilized to mange each LQR control strategy contribution level in the final control action. The simulation results show the advantages of the proposed control system over the individual AFS or DYC controllers.     

汽车操纵稳定性的中间位置转向试验

操纵稳定性中间位置转向试验最初是由美国德尔福公司制定的，是汽车在高速行驶条件下操纵性和稳定性的重要评价方法。通过试验的原始数据可以绘制出转向盘转角与侧向加速度、转向盘力矩与侧向加速度、转向盘力矩与转向盘转角等多条特性曲线，以作为不同的评价指标。以CAll41载货汽车作为实例分析，发现该车转向干摩擦偏大，转向刚度偏低，高速行驶时的非线性路感不够理想。     

载货汽车转向系统分析

阐述了载货汽午转向系统运动学特忭的计算方法和分析方法;研究了载货汽车原地转向阻力的主要组成及动力转向器的效率特性,给出了原地转向性能的计算分析方法。通过对4种动力转向系统匹配方案的分析表明,转向机构的传动比和动力转向器的效率对车辆原地转向性能具有重要影响。     

某氢燃料车型液压助力转向系统匹配设计

随着液压助力转向系统的不断应用与发展,人们对转向系统的要求越来越高。文章结合某氢燃料车型液压助力转向系统的设计,就该系统中的转向器和电动转向泵压力和流量进行匹配设计,对转向器垂臂摆角、转向油管的内径和油罐的容积、转向直拉杆的间隙和强度等进行设计和校核,确保了转向系统的安全性和合理性。     

Crosswind Feedforward Control - A Measure to Improve Vehicle Crosswind Behaviour

The theory of crosswind feedforward control was explained using the example of a vehicle with active front-wheel steering. Beforehand, the calculation formulas and frequency responses of the transient crosswind force and of the wind yaw moment acting on the vehicle were derived using the example of a simple vehicle fluid model. The influence of the transiency of crosswind disturbance on the dynamic crosswind behaviour of a vehicle was then presented. The results of simulation confirmed the analyses carried out in the frequency domain for feedforward control with front, rear and all-wheel steering. With front-wheel steering, the influence of crosswind on one of the vehicle movement variables (lateral acceleration or yaw rate) could be almost completely compensated by dynamic feedforward control. With rear-wheel steering, it is only possible to compensate directly for the influence on the yawing rate. Due to the setting of the side force in the same direction as the lateral wind force at the start, active rear-wheel steering is not so successful as active front-wheel steering. Nevertheless, the crosswind behaviour of a vehicle can be considerably enhanced by feedforward control with rear-wheel steering. The best crosswind behaviour was obtained with active all-wheel steering: the vehicle hardly responds at all to crosswinds and remains on course despite heavy gusts of wind.     

Modeling and control of an anti-lock brake and steering system for cooperative control on split-mu surfaces

The brake and steering systems in vehicles are the most effective actuators that directly affect the vehicle dynamics. In general, the brake system affects the longitudinal dynamics and the steering system affects the lateral dynamics; however, their effects are coupled when the vehicle is braking on a non-homogenous surface, such as a split-mu road. The yaw moment compensation of the steering control on a split-mu road is one of the basic functions of integrated or coordinated chassis control systems and has been demonstrated by several chassis suppliers. However, the disturbance yaw moment is generally compensated for using the yaw rate feedback or using wheel brake pressure measurement. Access to the wheel brake pressure through physical sensors is not cost effective; therefore, we modeled the hydraulic brake system to avoid using physical sensors and to estimate the brake pressure. The steering angle controller was designed to mitigate the non-symmetric braking force effect and to stabilize the yaw rate dynamics of the vehicle. An H-infinity design synthesis was used to take the system model and the estimation errors into account, and the designed controller was evaluated using vehicle tests.