The Development of a Fuzzy Predictive Control System for Automotive Anti-lock Braking System

This paper presents the model of one-tire kinetics、tires、the braking system and the model of control system.On virtual road,this paper builds a fuzzy predictive control system to insure the best attachment coefficient between tires and road. And it turns out to be that this fuzzy predictive control method has achieved good performances.

Integrated Active Suspension and Anti-Lock Braking Control for Four-Wheel-Independent-Drive Electric Vehicles

This paper presents an integrated control scheme for enhancing the ride comfort and handling performance of a four-wheel-independent-drive electric vehicle through the coordination of active suspension system(ASS)and anti-lock braking system(ABS).First,a longitudinal-vertical coupled vehicle dynamics model is established by integrating a road input model.Then the coupling mechanisms between longitudinal and vertical vehicle dynamics are analyzed.An ASS-ABS integrated control system is proposed,utilizing an H∞controller for ASS to optimize load transfer effect and a neural network sliding mode control for ABS implementation.Finally,the effectiveness of the proposed control scheme is evaluated through comprehensive tests conducted on a hardware-in-loop(HIL)test platform.The HIL test results demonstrate that the proposed control scheme can significantly improve the braking performance and ride comfort compared to conventional ABS control methods.

Application of shortened heat treatment cycles on A356 automotive brake calipers with respective globular and dendritic microstructures

Since the automotive industry has many possible applications for semi-solid metal (SSM)-high-pressure die casting (HPDC) parts, the newly developed heat treatment cycles, as well as the traditional heat treatment cycles, were applied to A356 brake calipers cast using a LK DCC630 HPDC machine.Vickers hardness measurements at a cross section of the brake calipers were performed, indicating that similar values can be obtained when using the significantly shorter heat treatment cycles.Finally, the typical tensile properties that can be obtained for SSM-HPDC A356 brake calipers are compared with those manufactured by gravity die casting.Results indicate that the differences in microstructures (globular or dendritic) do not have a noteworthy effect on the heat treatment response.This implies that the short heat treatment cycles originally developed for globular SSM-HPDC A356 castings can be successfully applied to dendritic liquid A356 castings too.

Identification and Modeling of Automotive Electrical Parking Brake System for SiL Simulation

To evaluate the software behavior of the electronic control unit （ECU） of automotive electrical parking brake （EPB）, a software- in-the-loop （SiL） simulation system is built. The EPB is simulated by ARX （auto-regressive with auxiliary input） model, ARMAX （auto-regressive moving average with auxiliary input） model, and NNARMAX （neural network ARMAX） model. By system identification, the ARX（3,4,2）, ARX（4,4,2）, ARMAX（3,3,1,1）, and ARMAX（4,4,3,2） models are derived. Validation results show that the four-order ARMAX model and the NNARMAX model better simulate the actuator of the EPB.

Design and Analysis of Electro-mechanical Hybrid Anti-lock Braking System for Hybrid Electric Vehicle Utilizing Motor Regenerative Braking

Braking on low adhesion-coefficient roads, hybrid electric vehicle＇s motor regenerative torque is switched off to safeguard the normal anti-lock braking system （ABS） fimction. When the ABS control is terminated, the motor regenerative braking is readmitted. Aiming at avoiding permanent cycles from hydraulic anti-lock braking to motor regenerative braking, a novel electro-mechanical hybrid anti-lock braking system using fuzzy logic is designed. Different from the traditional single control structure, this system has a two-layered hierarchical structure, The first layer is responsible for harmonious adjustment or interaction between regenerative system and anti-lock braking system. The second layer is responsible for braking torque distribution and adjustment. The closed-loop simulation model is built. Control strategy and method for coordination between regenerative and anti-lock braking are developed. Simulation braking on low adhesion-coefficient roads with fuzzy logic control and real vehicle braking field test are presented. The results from simulating analysis and experiment show braking performance of the vehicle is perfect, harmonious coordination between regenerative and anti-lock braking function, significant amount of braking energy can be recovered and the proposed control strategy and method are effective.

Development of a Low-cost Hardware-in-the-loop Simulation System as a Test Bench for Anti-lock Braking System

Nowadays validation of anti-lock braking systems（ABS） relies mainly on a large amount of road tests.An alternative means with higher efficiency is employing the hardware-in-the-loop simulation（HILS） system to substitute part of road tests for designing,testing,and tuning electronic control units（ECUs） of ABS.Most HILS systems for ABS use expensive digital signal processor hardware and special purpose software,and some fail-safe functions with regard to wheel speeds cannot be evaluated since artificial wheel speed signals are usually provided.In this paper,a low-cost ABS HILS test bench is developed and used for validating the anti-lock braking performance and tuning control parameters of ABS controllers.Another important merit of the proposed test bench is that it can comprehensively evaluate the fail-safe functions with regard to wheel speed signals since real tone rings and sensors are integrated in the bench.A 5-DOF vehicle model with consideration of longitudinal load transfer is used to calculate tire forces,wheel speeds and vehicle speed.Each of the four real-time wheel speed signal generators consists of a servo motor plus a ring gear,which has sufficient dynamic response ability to emulate the rapid changes of the wheel speeds under strict braking conditions of very slippery roads.The simulation of braking tests under different road adhesion coefficients using the HILS test bench is run,and results show that it can evaluate the anti-lock braking performance of ABS and partly the fail-safe functions.This HILS system can also be used in such applications as durability test,benchmarking and comparison between different ECUs.The test bench developed not only has a relatively low cost,but also can be used to validate the wheel speed-related ECU design and all its fail-safe functions,and a rapid testing and proving platform with a high efficiency for research and development of the automotive ABS is therefore provided.

New Method of Road Surface Identification in Anti-Lock Braking System

Based on the vehicle-road dynamic model, the road characteristic parameter, which depends on different types of road surfaces, is introduced and a new method of road surface identification for automotive anti-lock braking system (ABS) is proposed. According to the characteristics of vehicle-road dynamic model, a simple math resolution method of the model's factors is established. Only using the information of wheel speed, the vehicle reference velocity and the wheel slip ratio are estimated real-timely. And based on the wheel dynamic model, the road characteristic parameter is determined to identify the road surface for the determination of thresholds of ABS regulative parameters. With this new method, the road surface identification can be accurately obtained and calculation time is short that it can meet the ABS real time control need, and it also improves the performance of ABS.

汽车制动器系统稳定性响应的不确定性和相关性分析

在制动噪声现象中,汽车制动器系统参数不可避免地存在着不确定性和相关性,使得系统响应亦可能同时存在一定的不确定性和相关性,针对该问题开展了制动器系统稳定性响应的不确定性和相关性分析研究。采用多椭球凸模型描述系统参数的不确定性和相关性,以不稳定模态阻尼比表征系统稳定性响应。将多椭球凸模型分别与蒙特卡罗仿真、一阶摄动法和二阶摄动法相结合,提出了三种系统稳定性响应的不确定性分析方法;结合蒙特卡罗仿真和一阶摄动法,分别提出了两种系统不确定响应的相关性分析方法;基于不确定性和相关性分析方法,提出了建立系统响应椭球域的组合方法。通过算例分析验证了方法的有效性。分析结果表明,所提出的方法可有效地求得系统稳定性响应的边界区间、相关系数和椭球域,并且该方法具有较高的计算精度和效率。

泵控直驱式线控制动单元的设计与分析

为简化传统汽车制动系统结构,更好地满足智能网联汽车对制动力快速调节的需求,提出了一种泵控直驱式线控制动单元,采用泵控直驱容积伺服技术,通过伺服电机直接驱动双向齿轮泵,实现对制动轮缸压力的控制和快速调节,消除阀控系统的节流损失,有效提升系统效率。在泵控直驱式线控制动单元参数设计及数学建模的基础上,试制了制动单元样机与性能测试平台,分析了轮缸压力变化的响应曲线以及跟随特性。仿真和试验结果证明了泵控直驱式线控制动单元的可行性,12 MPa压力阶跃响应时间为200 ms,系统具有良好的响应速度和稳定性,为线控制动技术提供了一种新的实施方案。

汽车电子机械制动器失效容错控制方法研究

汽车电子机械制动器失效会产生多个方面的信号,在传输过程中易丢失,造成汽车电子制动可靠性降低,影响汽车行驶安全,为此提出了汽车电子机械制动器失效容错控制方法。从汽车电子机械制动器控制原理出发,利用支持向量机(SVM)构建失效行为检测模型,通过失效预测与失效辨识2部分,有效检测汽车电子机械制动器失效行为;设计自适应制动器失效容错控制模型,通过阻断、隔离导致制动器失效的传感器信号,以估计信号代替导致制动器失效传感器信号,完成汽车电子制动器失效容错控制。实验结果表明,该方法可实现汽车电子机械制动器失效容错控制,并且控制效果较好,可有效提升汽车制动可靠性。

平板式汽车制动检验台的使用探究

汽车制动性能检验是汽车安全技术检验的重要组成,也是汽车运行安全的基本保障。目前主要采用台式检验设备进行检验,其中平板式汽车制动检验台是运用较多的设备之一。在实际的机汽车制动性能检验工作中,由于检验人员对检验原理、检验标准、设备使用等理解不够,导致出现使用不当、数据偏离等现象,不能真实反映汽车制动系统状况。如何正确使用平板式汽车制动检验台进行检验,是检验机构从业人员应该认真学习、领会的技能。下面笔者从汽车制动原理切入,描述汽车在检验台的测试过程,并根据实践总结影响检验台测试结果的因素,以及如何正确使用检验台。

基于滚柱丝杠执行装置的汽车电子制动器设计

文章提出和建立了一套以行星滚柱丝杠作为执行机构的汽车电子制动的方法体系。该方法的核心是通过减小行星滚柱丝杠的实际导程,从而实现较大承载能力和等效减速比,进而取消减速机构,达到简化结构、缩小体积、减轻重量的目的。阐述了电机转子直接驱动行星滚柱丝杠的螺母从而实现一体化执行器的方法,分析了保证制动顺畅的运动和动力计算的基本关系。某型号汽车电子制动器设计实例表明,汽车电子制动器与现有液压制动器比较,电子制动钳径向尺寸略小,导程小于0.54,可实现的减速比大于5,可替代现有的液压制动器。

汽车用制动器衬片质量存在的问题和对策

汽车制动器性能的稳定与否直接关系到驾驶员和乘客的生命安全,制动器衬片作为制动系统的重要组成部分其质量的好坏对制动器的性能有着直接影响。本文将深入探讨汽车用制动器衬片质量存在的问题和对策,以期解决制动器衬片质量存在的问题,提升汽车制动器的安全性能。

汽车制动系统故障分析与维修策略

本文深入探讨了汽车制动系统的工作原理、常见故障及其原因,并提出了针对性的维修策略。通过对制动系统关键部件如制动液、制动器、制动管路的检查与维护,本文强调了定期维护的重要性,并指出这是确保汽车安全行驶、保护驾驶者及乘客安全的关键措施。此外,文章还讨论了制动系统故障对行车安全的影响,提醒车主意识到定期检查和适时维护的必要性。

Investigation into precision engineering design and development of the next-generation brake discs using Al/SiC metal matrix composites

Substantially lightweight brake discs with high wear resistance are highly desirable in the automotive industry.This paper presents an investigation of the precision-engineering design and development of automotive brake discs using nonhomogeneous Al/SiC metal-matrixcomposite materials.The design and development are based on modeling and analysis following stringent precision-engineering principles,i.e.,brake-disc systems that operate repeatably and stably over time as enabled by precision-engineering design.The design and development are further supported by tribological experimental testing and finite-element simulations.The results show the industrial feasibility of the innovative design approach and the application merits of using advanced metal-matrix-composite materials for next-generation automotive and electric vehicles.

重型载货汽车长下坡制动工况辨识

传统持续制动系统过度依靠驾驶人主观判断实现开启和关闭,易出现不当操作引起整车制动性能热衰退问题,为此该文提出了重型载货汽车长下坡制动工况构建及辨识方法,为持续制动系统介入或退出主动控制提供依据。以重型载货汽车长下坡试验数据为基础,包含制动踏板动作、车速及GPS数据,利用短行程划分、K聚类和编码技术,基于Markov-Monte Carlo方法构建了长下坡制动工况,总时长1194 s,路程21.18 km;基于滚动时间窗原理建立反向传播(BP)神经网络工况辨识模型并进行离线训练和识别验证,结果表明:一般制动和强制动工况识别准确率达到89.30%,显示出提出的重型载货汽车长下坡制动工况构建及辨识方法能够有效识别车辆制动状态。

大型货运车辆辅助制动性能试验研究

为了解决大型货运车辆在下长坡路段行驶时,长时间制动会造成主制动器的热衰退,容易引发道路交通事故的问题,合理利用车辆辅助制动,从而缓解主制动器的热衰退现象,通过车辆辅助制动滑行理论分析和实车试验,探究大型货运车辆的辅助制动性能。结果表明:在相同车速条件下,变速器挡位越低,发动机制动力和排气制动力均越大;在相同挡位条件下,随着车速的增大,发动机制动力和排气制动力逐渐增大,并且挡位越低,制动力随车速变化越快;在相同车速、挡位条件下,排气制动效能更高,制动力大于发动机制动力。

新能源汽车的电控制动系统分析

阐述汽车电机和电控系统的特性、电控机械制动系统结构特点,分析自动化系统的工作流程、制动系统功能,这些功能包括驻车制动、动态起步辅助、动态紧急制动、自动驻车,从而自主研发创新。

面向智能车辆的EMB系统功能安全分析及应用设计

为提高电子机械制动(EMB)系统的可靠性,基于ISO26262标准,开展EMB系统功能安全分析及设计。面向智能驾驶车辆,进行相关项定义;应用危害分析和风险评估(HARA)方法论,得到汽车安全完整性等级(ASIL)和系统安全目标,并建立系统安全机制,通过故障树(FTA)模型进行安全验证,实现安全目标的逐层分解;基于EMB系统安全机制搭建失效控制模块,设计制动力重构算法并利用联合仿真模型进行系统验证。结果表明:该系统设计方案同时满足应用于智能车辆的EMB系统的功能需求和安全需求。

基于本体论的AEB关键场景生成方法研究

为满足自动紧急制动功能仿真测试的复杂验证需求,解决海量测试场景无法进行全覆盖的遍历式测试问题。通过设计面向自动紧急制动(AEB)功能的环境本体生成测试用例,本体自动转换生成组合测试的输入模型,再使用组合测试生成测试用例,获得的抽象测试用例用于生成具体的测试场景。上述场景为验证AEB功能的仿真测试提供了基础。仿真结果表明,生成的测试场景能够满足AEB功能测试要求,检测到AEB功能关键场景,且相比于遍历式测试,能够提高测试效率。