汽车转向梯形故障检测机理研究

通过对汽车转向梯形机构进行合理简化,建立了相应的数学模型,推导出了汽车前轮转向前张角与转向梯形底角之间的变化规律:当汽车外侧车轮转到某一定值时,内侧车轮转角受同侧梯形底角的影响,并且内轮转角变化与同侧梯形底角变化成反比。经试验验证了此结论的正确性,由此使得利用现有的检测设备即可实现对汽车转向梯形工作状态的在线检测。     

Application of Inverse Models to Vehicle Optimization Problems

This paper presents a nonlinear inverse model of a road vehicle which simulates combined steering and braking/driving. The inputs to the model are the lateral and longitudinal acceleration of the vehicle's sprung mass center. The simulation returns the steering wheel angle and brake/drive torques required to obtain the desired accelerations. An example is presented which demonstrates the utility of inverse models for optimization purposes.     

Nähere Untersuchungen zur stationären Kurvenfahrt von Einspurfahrzeugen

Detailed Investigations of the Steady State Turning of Single Track Vehicles

In the paper the steady state turning of single track vehicles on a horizontal, even road is investigated, supposing the air to be at rest. The vehicle model used has six degrees of freedom: rolling, yawing, pitching and bouncing of the vehicle, rotation of the front wheel system (steering) relatively to the main frame and distortion of the rear wheel system due to limited stiffness of its linkage, and also takes into account wind drag and gyroscopic effects generated by wheels and other vehicle components. A special importance is given to the geometry of the vehicle

The results show a comparison of two types of motorcycles with different geometries and tires. To characterize the vehicle behaviour the roll, side slip and steering angle as functions of the normal acceleration are used. A more detailed study in respect to the steering torque is added.     

Influencing driver chosen cornering speed by means of modified steering feel

This paper presents an investigation about influencing the driver's behaviour intuitively by means of modified steering feel. For a rollover indication through haptic feedback a model was developed and tested that returned a warning to the driver about too high vehicle speed. This was realised by modifying the experienced steering wheel torque as a function of the lateral acceleration. The hypothesis for this work was that drivers of heavy vehicles will perform with more margin of safety to the rollover threshold if the steering feel is altered by means of decreased or additionally increased steering wheel torque at high lateral acceleration. Therefore, the model was implemented in a test truck with active steering with torque overlay and used for a track test. Thirty-three drivers took part in the investigation that showed, depending on the parameter setting, a significant decrease of lateral acceleration while cornering.     

基于模态分析的汽车转向盘怠速抖动优化

针对某轿车怠速开空调转向盘抖动的问题,对转向盘和排气系统模态进行分析,发现该车转向盘和排气系统在约束条件下的模态参数与发动机的2阶点火频率相一致.调整了其转向盘和排气系统的模态,并针对优化后转向盘进行了振动试验.结果表明,转向盘X方向的振动由0.90 m/s2降为0.31 m/s2,Y方向的振动由1.05 m/s2降为...     

某车型高速行驶方向盘摆振分析

研究高速行驶方向盘摆振影响因素与测试方法。针对某款乘用车方向盘摆振的现象进行原因分析,通过对其进行道路再现试验,测试分析轮胎至方向盘的灵敏度,可知该车对轮胎异相位的激励非常灵敏;以副车架为参考点,建立模型,通过ODS分析进一步验证摆振产生原因。该研究为高速行驶方向盘摆振问题的解决提供依据。     

分布式驱动电动汽车转向工况转矩分配控制研究

针对分布式驱动车辆转向工况在低速下期望提高转向机动性能，高速下期望保证行驶稳定性的需求，充分考虑转向行驶内外侧车轮的转向关系以及车辆动力学，制定了适应车速变化的四轮转矩分配策略，建立了四轮轮毂电机驱动模型以及二自由度参考模型。为了改善分布式驱动转向机动性能，建立自抗扰控制器调整内外侧车轮转矩，形成合理的转速差，减小转向半径，以提高转向机动性；对于高速转向行驶稳定性的需求，通过二次规划方法优化分配各车轮驱动力矩，分析轮胎纵横向附着裕度建立目标函数，并加入附加横摆力矩和路面附着力的限制，进行车轮驱动转矩的在线优化分配，提高车辆转向行驶的稳定性；另外为避免2种控制模式转换时驱动转矩突变，根据车速和稳定性参数制定模糊规则决策2种模式的协调系数，保证2种控制模式的平滑过渡。基于CarSim和MATLAB/Simulink进行联合仿真，并搭建硬件在环平台进行试验，对所提出的方法进行验证。结果表明：在低速转向工况下，提出的分配策略能够调节内外侧车轮产生差速效果，与转矩平均分配的策略相比，转向半径有所减小，提高车辆机动性；高速转向工况下，分配策略能够保证车辆稳定转向，与未考虑稳定性控制的分配策略相比，能更好地跟踪目标轨迹，且横摆角速度控制在参考横摆角速度附近，证明了所提控制策略的有效性。     

关于车辆方向盘摆振的补偿方法及补偿系统研究

研究电动助力转向系统对方向盘摆振补偿的功能,通过对影响方向盘摆振因素的分解,当整车基本参数确定的情况下可以采用EPS进行摆振补偿.通过摆振补偿功能开发到某车型实车测试验证,有效解决高速制动等工况下方向盘摆振问题.该研究为车辆方向盘摆振问题的解决提供采用EPS补偿万式提供方法及系统.     

Nonlinear PI front and rear steering control in four wheel steering vehicles

Vehicle steering dynamics show resonances, which depend on the longitudinal speed, unstable equilibrium points and limited stability regions depending on the constant steering wheel angle, longitudinal speed and car parameters.

The main contribution of this paper is to show that a combined decentralized proportional active front steering control and proportional-integral active rear steering control from the yaw rate tracking error can assign the eigenvalues of the linearised single track steering dynamics, without lateral speed measurements, using a standard single track car model with nonlinear tire characteristics and a non-linear first-order reference model for the yaw rate dynamics driven by the driver steering wheel input. By choosing a suitable nonlinear reference model it is shown that the responses to driver step inputs tend to zero (or reduced) lateral speed for any value of longitudinal speed: in this case the resulting controlled vehicle static gain from driver input to yaw rate differs from the uncontrolled one at higher speed. The closed loop system shows the advantages of both active front and rear steering control: higher controllability, enlarged bandwidth for the yaw rate dynamics, suppressed resonances, new stable cornering manoeuvres, enlarged stability regions, reduced lateral speed and improved manoeuvrability; in addition comfort is improved since the phase lag between lateral acceleration and yaw rate is reduced.

For the designed control law a robustness analysis is presented with respect to system failures, driver step inputs and critical car parameters such as mass, moment of inertia and front and rear cornering stiffness coefficients. Several simulations are carried out on a higher order experimentally validated nonlinear dynamical model to confirm the analysis and to explore the robustness with respect to unmodelled dynamics.     

Nonlinear PI front and rear steering control in four wheel steering vehicles

Vehicle steering dynamics show resonances, which depend on the longitudinal speed, unstable equilibrium points and limited stability regions depending on the constant steering wheel angle, longitudinal speed and car parameters.

The main contribution of this paper is to show that a combined decentralized proportional active front steering control and proportional-integral active rear steering control from the yaw rate tracking error can assign the eigenvalues of the linearised single track steering dynamics, without lateral speed measurements, using a standard single track car model with nonlinear tire characteristics and a non-linear first-order reference model for the yaw rate dynamics driven by the driver steering wheel input. By choosing a suitable nonlinear reference model it is shown that the responses to driver step inputs tend to zero (or reduced) lateral speed for any value of longitudinal speed: in this case the resulting controlled vehicle static gain from driver input to yaw rate differs from the uncontrolled one at higher speed. The closed loop system shows the advantages of both active front and rear steering control: higher controllability, enlarged bandwidth for the yaw rate dynamics, suppressed resonances, new stable cornering manoeuvres, enlarged stability regions, reduced lateral speed and improved manoeuvrability; in addition comfort is improved since the phase lag between lateral acceleration and yaw rate is reduced.

For the designed control law a robustness analysis is presented with respect to system failures, driver step inputs and critical car parameters such as mass, moment of inertia and front and rear cornering stiffness coefficients. Several simulations are carried out on a higher order experimentally validated nonlinear dynamical model to confirm the analysis and to explore the robustness with respect to unmodelled dynamics.     

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。     

Robust control and actuator dynamics compensation for railway vehicles

A robust controller is designed for active steering of a high speed train bogie with solid axle wheel sets to reduce track irregularity effects on the vehicle’s dynamics and improve stability and curving performance. A half-car railway vehicle model with seven degrees of freedom equipped with practical accelerometers and angular velocity sensors is considered for the H_∞ control design. The controller is robust against the wheel/rail contact parameter variations. Field measurement data are used as the track irregularities in simulations. The control force is applied to the vehicle model via ball-screw electromechanical actuators. To compensate the actuator dynamics, the time delay is identified online and is used in a second-order polynomial extrapolation carried out to predict and modify the control command to the actuator. The performance of the proposed controller and actuator dynamics compensation technique are examined on a one-car railway vehicle model with realistic structural parameters and nonlinear wheel and rail profiles. The results showed that for the case of nonlinear wheel and rail profiles significant improvements in the active control performance can be achieved using the proposed compensation technique.     

An analysis of driver’s steering behaviour during auditory or haptic warnings for the designing of lane departure warning system

We found that the steering vibration was effective for warning of lane-departure situations, especially when drivers did not know the meaning of warnings. It seems that many drivers have their own Mental Model for response to a haptic stimulus transmitted through the steering wheel. This mental model causes drivers to think that the vehicle is deviating from the lane when steering vibration was used as the warning signal. We can conclude that the mental model for the warnings should make interpreting vehicle conditions easy, especially when the haptic warning is transmitted through the steering wheel.     

某中型4×2载货车方向盘自动偏转问题的分析与改进

针对某中型4×2载货车空车到装满货物后方向盘自动偏转的问题,文章从转向传动系统与前悬架系统运动协调性的角度进行分析,分别借助作图法和ADAMS软件对转向传动系统与前悬架系统之间运动干涉量进行计算分析,并提出具体的优化改进措施,解决整车加载过程中方向盘偏转的问题。     

Simulation of curving at low speed under high traction for passive steering hauling locomotives

The traction control in modern electric and diesel electric locomotives has allowed rail operators to utilise high traction adhesion levels without undue risk of damage from uncontrolled wheel spin. At the same time, some locomotive manufacturers have developed passive steering locomotive bogies to reduce wheel rail wear and further improve locomotive adhesion performance on curves. High locomotive traction loads in curving are known to cause the loss of steering performance in passive steering bogies. At present there are few publications on the curving performance of locomotive steering with linkage bogies. The most extreme traction curving cases of low speed and high adhesion for hauling locomotives have not been fully investigated, with effects of coupler forces and cant excess being generally ignored. This paper presents a simulation study for three axle bogie locomotives in pusher and pulling train positions on tight curves. The simulation study uses moderate and high traction adhesion levels of 16.6% and 37% for various rail friction conditions. Curving performance is assessed, showing forced steering bogies to have considerable advantages over self steering bogies. Likewise it is shown that self steering bogies are significantly better than yaw relaxation bogies at improving steering under traction. As the required traction adhesion approaches the rail friction coefficient, steering performance of all bogies degrades and yaw of the bogie frame relative to the track increases. Operation with excess cant and tensile coupler forces are both found to be detrimental to the wear performance of all locomotive bogies, increasing the bogie frame yaw angles. Bogie frame pitching is also found to have significant effect on steering, causing increased performance differences between bogie designs.     

Steady-state steering of a tilting three-wheeled vehicle

The design of a narrow-track enclosed vehicle for urban transport was the subject of the CLEVER project. Due to its narrow track and requirement for car-like controls, an actively controlled tilting system was integrated into the chassis to allow for high lateral accelerations without rolling over. The cornering behaviour of this unique vehicle concept is investigated and compared with the ideal Ackermann response. The steer kinematics of this 1F1T (one front wheel, one wheel tilting) configuration are assessed through the use of a steady-state steering model, with attention focused on how steer parameters such as tilt axis height and inclination can be tuned to provide the required response. A prototype vehicle was designed and built and the results of experimental testing are presented to illustrate the real balancing performance of the combined steering and tilting approach used for the CLEVER vehicle. The experimental results follow the trends demonstrated in the model.     

线控转向系统路感模糊控制仿真分析

驾驶员希望通过转向盘的力矩信息感知汽车的行驶状态。文章主要研究汽车转向盘力特性与转向盘转角、车速、侧向加速度及转向阻力矩的关系,运用多变量模糊控制技术研究了线控转向系统的路感,通过ADAMS提供离线汽车数据,在Matlab／Simulink中对路感多变量模糊控制器进行了仿真,并对其中一种控制结构进行了硬件在环试验,给出了路感多变量模糊控制的一种参数调整方法以及路感数据。表明仿真同硬件在环仿真结果基本一致,验证了路感多变量模糊控制方法可行。     

SUV转向系统模态试验及优化

针对某SUV车转向系统方向盘怠速抖振过大的现象,采用模态试验技术得到转向系统的固有频率,找到产生这种现象的原因在于转向系统的固有频率和发动机怠速时的振动激励频率接近,从而引起了方向盘的过大振动。文章采用增大转向管柱的支架和车身连接处的接触面面积的方法进行结构优化,并对优化后的转向系统进行模态试验,再将优化前后方向盘的振动数据进行对比,发现优化后的转向系统振动明显改善,达到了减振的目的。     

某微型车方向盘抖动控制策略

针对某微型车在时速80 km/h以上出现方向盘抖动严重的问题,采用试验分析、数据统计及模态测试等方法,测得方向盘Y向振动加速度最高达到0.95 g,并确定方向盘抖动的主要原因为转向器模态与轮胎高速转动频率发生耦合.通过将转向器导套长度由10 mm增加到16 mm,控制齿轮条间隙在0.08 mm以下,提高了转向器刚度,从而将最大振动加速度降至0.12 g.经试验确认,改进后的方向盘抖动情况明显改善,满足改进目标.     

基于统一模型的转向-悬架系统最优综合控制方法

通过对车辆底盘系统中的转向和悬架系统建立统一的数学模型,利用M atlab/S imu link仿真,结合最优控制理论,分别对被动悬架兼前轮转向系统与主动悬架兼四轮转向综合控制系统进行了对比研究。理论分析与仿真试验表明,综合控制系统下车辆的操纵稳定性和平顺性都得到了很大的提高。