Design of a hydraulic anti-lock braking modulator and an intelligent brake pressure controller for a light motorcycle

The object of this paper is to design a new hydraulic modulator and an intelligent sliding mode pulse width modulation (PWM) brake pressure controller for an anti-lock braking system, for application to light motorcycles. The paper presents a design principle and a mathematical analysis of the hydraulic anti-lock braking modulator. The intelligent sliding mode PWM brake pressure controller based on vehicle acceleration is designed and tested. A three-phase pavement experiment and a rear brake influence test are undertaken to verify the performance of the controller and the modulator. A light motorcycle is built for the real vehicle anti-lock braking experiments. The experimental results show that both the intelligent controller and the hydraulic modulator designed in the study perform well in the anti-lock braking operation.     

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.     

一种汽车ESP仿真模型的研究

基于Pacejka的"魔术公式"轮胎模型,建立了包括汽车纵向与横向移动、横摆、侧倾和4个车轮的转动的8自由度动力学模型.设计了由汽车仿真模型和驱动系统、四通道制动系统、制动踏板、转向盘与油门踏板等实物以及控制器(ESP)等部分组成的半实物仿真平台.以侧向加速度与横摆角速度为仿真控制变量对模型进行仿真测试.仿真与实车测试数据相当接近,为ESP的研究提供了有效的模型.     

Kinematics of a smart variable caster mechanism for a vehicle steerable wheel

The lateral force of a tyre is a function of the sideslip and camber angles. The camber angle can provide a significant effect on the stability of a vehicle by increasing or adjusting the required lateral force to keep the vehicle on the road. To control the camber angle and hence, the lateral force of each tyre, we can use the caster angle of the wheel. We introduce a possible variable and controllable caster angle ? in order to adjust the camber angle when the sideslip angle cannot be changed. As long as the left and right wheels are steering together according to a kinematic condition, such as Ackerman, the sideslip angle of the inner wheel cannot be increased independently to alter the reduced lateral force because of weight transfer and reduction of the normal load F _z . A variable caster mechanism can adjust the caster angle of the wheels to achieve their top capacity and maximise the lateral force, when needed. Such a system would potentially increase the safety, stability, and maneuverability of the vehicles. Using the screw theory, this paper will examine the kinematics of a variable caster and present the required mathematical equation to calculate the camber angle as a function of suspension mechanism parameters and other relevant variables. Having a steered wheel about a tilted steering axis will change the position and orientation of the wheel with respect to the body of the car. This paper provides the required kinematics of such a suspension and extracts the equations in special practical situations. The analysis is for an ideal situation in which we substitute the tyre with its equivalent disc at the tyre plane.     

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.     

Modeling and Analysis of Automotive Antilock Brake Systems Subject to Vehicle Payload Shifting

The steerability and stability of vehicles must be maintained during emergency stopping and evasive driving maneuvers on degraded road surfaces. The introduction of antilock brake and traction control systems (ABS/TCS) has expanded the envelope of safe vehicle operation for the majority of drivers. These mechatronic systems combine an electronic controller with wheel speed sensors, an electro-mechanical hydraulic brake actuator, and in some instances, engine intervention through the engine control unit, to regulate wheel slip. The development of ABS systems has traditionally depended on extensive in-vehicle testing, at cold weather proving grounds, which contribute to lengthy product development cycles. However, recent attention has been focused on the use of simulation and hardware-in-the-loop strategies to emulate test conditions in a controlled setting to shorten product design time and methodically address critical safety issues. In this paper, the effect of transient load shifting due to cargo movement on ABS performance in light-duty vehicles will be investigated. Analytical and empirical mathematical models are presented to describe the chassis, tire/road interface, wheel, brake modulator, and cargo dynamics. Two strategies, a model-free table lookup and model-based discrete nonlinear controller, are presented to regulate the ABS modulator's operation. These vehicle and controller dynamics have been integrated into a simulation tool to investigate the effect of transient weight transfers on the vehicle's overall stopping distance and time. Representative numerical results are presented and discussed to quantify the ABS systems' performance for various loading and operating conditions.     

汽车电子防抱制动系统仿真的研究

本文分析了汽车车轮制动瞬态动力学，结合精确的１５自由度空间刚体动力学模型，定量地分析了车轮抱死松开所获得的加减速度值，并为防抱制动提供了准确的加减速度阈值，同时考虑到防抱制动系统本身装置的特性，提出了最佳又符合实际的制动矩控制参数，使用仿真结果更接近实际，为电子防抱制动系统的研究提供较完整的理论体系和分析方法，并开发了汽车电子防抱制动系统模型（ＨＶＯＳＭ－ＡＢＳ）及模拟程序，该程序具有１６种不同的     

Nonlinear optimal integrated vehicle control using individual braking torque and steering angle with on-line control allocation by using state-dependent Riccati equation technique

This paper proposes the solution of state-dependent Riccati equation as a nonlinear optimal regulator to stabilise the motion dynamics of the vehicle model subjected to sudden disturbance inputs in the lateral direction. The proposed nonlinear regulator coordinates individually actuated wheel braking torque and steering wheel angle simultaneously in an optimal manner. Performance criteria are satisfied by solving the Riccati equation based on the given cost function subjected to the nonlinear vehicle dynamics. On-line control allocation in terms of optimal brake torque distribution enhanced by optimal wheel steering angle input is achieved. Furthermore, the proposed optimal nonlinear regulator is an active fault-tolerant control system against partial by-wire actuator failures while guaranteeing stability with good performance due to its capability to allocate the individual control inputs in an optimal way. The main aim is to stabilise the motion dynamics of the vehicle model during short-term emergency situations along the desired straight trajectory manageable by average drivers and to provide vehicle stability and handling predictability through the interaction of individual wheel braking and steering actuators. Simulation results are used to illustrate the effectiveness of the proposed methodology.     

汽车ABS液压调节器建模与分析

汽车ABS液压调节器是ABS的执行机构,它的性能好坏直接影响着汽车制动效能。为研究和评价ABS液压调节器性能,文章在分析调节器的组成和工作原理的基础上,基于AMESim建立了包括液压调节器、制动主缸及制动轮缸的模型,对影响调节器动态响应特性的制动液和控制阀(增、减压阀)结构因素进行了仿真分析;并针对某型号调节器进行了台架试验。试验结果表明,基于AMESim的汽车ABS液压调节器仿真结果与试验结果基本吻合。AMESim建模为调节器的研究提供了一种行之有效的方法。     

基于模糊PID的汽车防抱制动系统控制策略的研究

在基于滑移率的ABS控制策略的基础上,建立了11自由度的汽车急转制动仿真模型。提出了一种参数自整定模糊PID控制算法,并采用了Bang-Bang控制和模糊PID控制分别对汽车ABS进行了仿真,其结果表明:模糊PID控制比Bang-Bang控制可以达到更好的效果。     

基于模糊控制方法的防抱控制系统的研究

本文采用模糊控制方法对车辆防抱制动系统进行了模拟研究，采用单轮的车辆模拟模型，用两种方法研究了防抱系统，即基于车轮滑移率的连续控制系统和基于车轮加减速度及参考滑移率的非连续控制系统。     

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。     

基于MATLAB/SIMULINK的车轮外倾角对车辆高速转向稳定性的影响研究

基于Matlab/Simulink建立了考虑汽车车身侧倾转向的3自由度仿真模型,研究了车轮外倾角对汽车高速转向稳定性的影响。结果表明前轮正外倾角、后轮负外倾角有利于提高转向稳定性,特别是在大转角的危险工况可以避免发生侧滑和侧翻。     

System identification and attitude control of motorcycle by computer-aided dynamics analysis

System identification of the motorcycle model constructed by computer-aided dynamics analysis is introduced to design a control system for attitude stabilization of the motorcycle. The identified model can be reduced to the coupled mode system between the roll and the front steering. The front-steering control system using the roll angle is designed by H_∞ control theory, based on the reduced-order model and the full-order model, respectively. It is verified from simulation results that the motorcycle attitude against disturbance is stabilized by the H_∞ controller, and that the reduced-order controller exhibits efficient stabilization performance in comparison with the full-order controller.     

前轮定位角对汽车转向回正作用的影响

利用数学方法，通过将前悬挂系统简化为相关杆系，论述了车轮外倾角、主销内倾角和后倾角以及转向轮转角改变时对汽车转向回正作用的影响，并求出了使汽车具有转向回正作用时，上述有关角度之间的数学关系。     

丰田LAND CRUISER吉普车ABS系统分析

简要介绍ＡＢＳ系统的作用，结合丰田ＬＡＮＤ ＣＲＵＩＳＥＲ吉普车装用的ＡＢＳ系统，详细分析了车轮转速传感器，负加速度传感器，ＡＢＳ ＣＥＵ和油压调节器的结构和工作原理，同时给出了该系统自动故障检测的代码，以及代码的意义。     

Drive control system design for stability and maneuverability of a 6WD/6WS vehicle

This paper describes a drive controller designed to improve the lateral vehicle stability and maneuverability of a 6-wheel drive / 6-wheel steering (6WD/6WS) vehicle. The drive controller consists of upper and lower level controllers. The upper level controller is based on sliding control theory and determines both front and middle steering angle, additional net yaw moment, and longitudinal net force according to the reference velocity and steering angle of a manual drive, remotely controlled, autonomous controller. The lower level controller takes the desired longitudinal net force, yaw moment, and tire force information as inputs and determines the additional front steering angle and distributed longitudinal tire force on each wheel. This controller is based on optimal distribution control and takes into consideration the friction circle related to the vertical tire force and friction coefficient acting on the road and tire. Distributed longitudinal/lateral tire forces are determined as proportion to the size of the friction circle according to changes in driving conditions. The response of the 6WD/6WS vehicle implemented with this drive controller has been evaluated via computer simulations conducted using the Matlab/Simulink dynamic model. Computer simulations of an open loop under turning conditions and a closed-loop driver model subjected to double lane change have been conducted to demonstrate the improved performance of the proposed drive controller over that of a conventional DYC.     

防抱死制动系统模糊自学习控制研究

由于车辆参数和运行工况的复杂多变，针对特定参数和路面条件所设计的防抱死制动系统往往难以适应。为解决这一问题，文中首先建立了带有盘式制动器的双轮车辆直线制动系统的数学模型；而后提出了模糊自学习控制策略，该方案通过引入模糊学习机制以调整模糊控制器的规则集，可使车辆对象输出跟踪理想参考模型的输出；接着对所设计控制算法在不同路面条件下进行了性能模拟；最后开发了模糊自学习微控制器，基于硬件在环仿真技术，对设计控制器的性能进行了实验验证。     

紧凑型扭杆弹簧悬架设计中车轮定位参数的计算

紧凑型扭杆弹簧悬架是普及型轿车中采用的一种主要的悬架结构形式。它属于纵臂式悬架,只能用于后轮,且不能用于转向轮,因此其定位参数只有车轮前束和外倾角两种。决定后轮定位参数的主要是与纵摆臂中制动鼓定位销轴空间有关的轴和孔的加工精度。对其几何模型和力学模型进行了分析,给出了该悬架车轮定位参数的计算方法,并以某车型为例进行了对比计算。