全挂车底盘制动系统故障树分析

采用故障树分析法对全挂车底盘制动系统进行了分析，计算了制动系统的失效率，并分析了影响制动系统失效的主要因素，提出了相应的改进建议。     

反力式挂车冲击制动系统检测试验平台设计

根据某型挂车的实际状况,设计出目前国内内较为少见的反力式挂车冲出制动系统检测试验平台.该试验平台采用整体式框架结构,单轴反力式双滚筒技术方案,能够对挂车的制动性能进行多项检测,且使用经济、便捷,为挂车装备保障提供了技术依据.     

挂车气制动系统响应时间测试系统设计与实现

正挂车气制动响应时间是评价其制动系统性能的重要指标,直接关系到行车安全性。通过分析挂车气制动系统结构和原理,针对GB 12676-2014《商用车辆和挂车制动系统技术要求及试验方法》标准中挂车制动响应时间性能要求,设计了挂车气制动系统响应时间检测系统,经过测试试验验证,测试系统满足标准GB 12676中的要求,为挂车气制动系统响应时间测试及设备研制提供了参考。     

解放牌CA141型载货汽车点制动的合理使用

对解放牌CA141型载货汽车制动系统进行了改造,解决了拖带挂车时,主车“点”制动而挂车无制动问题。改造后,还克服了原挂车断气制动一管两用放气时不能充气的弊病,确保下长坡过程中的行车安全。     

关于影响挂车自动制动响应时间的简单探讨

国内牵引车和挂车采用气压制动系统,其系统压力为0.85MPa,挂车在常规制动、紧急状况下的自动制动都可以通过牵引车来控制。挂车制动气源来自牵引车驻车回路,挂车与牵引车是通过两条管路进行连接的,其中红色管路为供能管路常有气,黄色管路为控制管路控制着挂车的制动和紧急状况下的自动制动。挂车分为半挂车和全挂车,本文讨论的是半挂车,对应的牵引车为半挂牵引车。     

装备EMB系统的挂车制动性能试验与分析

装备机械式电子制动系统(EMB,Electronic Mechanical Brake System)的挂车的制动性能特性与常规制动系统性能有很大区别,EMB系统具有响应时间短,制动效能高的特点,结合EMB制动系统的制动性能,搭建制动性能测试平台,对装备EMB系统的单轴和双轴挂车进行试验,从制动效能与制动协调性2个方面对装备EMB系统的挂车整车制动性能进行评价,分析制动过程中的制动减速度、制动力和制动距离的变化情况;并依据大量试验数据对比EMB系统与常规制动系统,验证EMB系统特性。     

一种新型的汽车列车行车制动系统

针对挂车列车行车制动时挂车制动延迟的问题,介绍了一种新型的行车制动系统的原理。     

手制动阀与挂车手制动阀的连接

对于载货车尤其是牵引车而言，要实现制动过程中主车和挂车的同步并不容易，常用的方法就是对挂车制动控制阀（装于主车上）以及挂车制动阀（装于挂车上）的控制口和出气口的气压值进行设定，使得阀体出气口的气压略高于控制口的气压，以达到略微提前于控制口动作的目的。但是实际效果并不理想，也就是说由于挂车制动控制及制动系统距离主车相对于主车制动系统要远很多，要实现挂车制动超前主车就更困难了。     

重型挂车的气制动控制

重型挂车的气制动类型,按其控制方法的不同来分,一般有充气制动和断气制动两种。一、充气制动系统,是将挂车的制动系通过软管与牵引车的制动系联成一体。由于动力气源的供应方法不同,又可分为单管路和双管路两种。1.单管路制动:挂车上不装储气筒,挂车的制动管路与牵引车的管路串联成一个整体。当牵引车的控制阀开启时,同时将压缩空气分配到牵引车和挂车的各车轮制动器气室。这种制动系统的结构虽然较简单,但由于从牵引车流向挂车的管路较长,气流受管道的阻力影响,使前、后轮的制动略有时差,故一般仅适用于半挂车或轮组较少的挂车。2.双管路制动:在挂车上装有一组储气筒,挂车车轮制动器所需的压缩空气由挂车储     

铰接车辆电涡流缓速器联合制动系统研究

提出利用联合制动系统将电涡流缓速器应用到铰接车辆上的方法。联合制动系统由拖车上的电涡流缓速器和挂车电控制动系统组成,二者在ECU控制下可以保证拖车与挂车制动力的合理分配以及对拖车及挂车的制动实施时间进行干预。采用该系统还可以减少铰接车辆行驶中某些事故的发生。     

Lateral dynamics of motorcycles towing single-wheeled trailers

A motorcycle towing a single-wheel trailer may provide useful transport for light cargo on narrow tracks and off-road use, particularly in rural areas of developing countries. Four designs of such trailers are described. Linear models are derived for the lateral dynamics of an off-road motorcycle towing this type of trailer straight ahead at constant speed. The trailers were tested behind an instrumented motorcycle. Linear autoregressive models were fitted to the experimental data using system identification techniques. Analytical and experimentally derived models largely agreed on frequency, damping and shape of the weave, wobble and trailer sway normal modes. The trailers made the motorcycle's steering heavier but the analytical models did not predict this. The location of the articulation axes between the motorcycle and the trailer were found to be critical for stability. The best trailer design handled well with loads up to 200 kg and speeds up to 70 km/h.     

Lateral dynamics of motorcycles towing single-wheeled trailers

A motorcycle towing a single-wheel trailer may provide useful transport for light cargo on narrow tracks and off-road use, particularly in rural areas of developing countries. Four designs of such trailers are described. Linear models are derived for the lateral dynamics of an off-road motorcycle towing this type of trailer straight ahead at constant speed. The trailers were tested behind an instrumented motorcycle. Linear autoregressive models were fitted to the experimental data using system identification techniques. Analytical and experimentally derived models largely agreed on frequency, damping and shape of the weave, wobble and trailer sway normal modes. The trailers made the motorcycle’s steering heavier but the analytical models did not predict this. The location of the articulation axes between the motorcycle and the trailer were found to be critical for stability. The best trailer design handled well with loads up to 200 kg and speeds up to 70 km/h.     

汽车列车的转弯半径计算

由于运输效率提升的需要,一辆汽车会拖挂多台挂车,为了满足后期运营场景,在设计之初就应对这种汽车列车的最小转弯半径进行计算,评估运营场地或道路情况。文章主要通过汽车列车转动时没有相对转动角速度这一前提条件,对拖拽多台挂车的汽车列车的最小转弯半径进行分析计算,从而得出拖拽3台挂车的最小转弯半径公式,并由此推导出拖拽n台挂车的转弯半径的计算公式。运用该公式对某一机场牵引列车进行计算,该公式的计算结果与实际运营场景相符,证实该公式可用于工程开发和实车应用评估。     

Investigation of influential factors of a brake corner system to reduce brake torque variation

This paper investigates the brake corner system to reduce brake torque variation in the brake judder problem. A numerical model for determining brake torque variation was constructed using the multi-body dynamics model. Using this model, the brake torque variation for a given disc thickness variation was obtained in the time domain. The multi-body dynamics model was verified by a dynamometer test via the comparison of brake torque variation and load distribution patterns of the pad. To reduce the simulation time and cost required to determine factors that influence the reduction in brake torque variation, a simple mathematical model was constructed and used to determine both the brake torque variation and influential factors. The multi-body dynamics model and dynamometer test were modified on the basis of the results of the simple mathematical model and deformed shape of the multi-body dynamics model. These influential factors were verified to reduce the brake torque variation.     

Ride Vibration Measurements of Agricultural Tractor and Trailer Combinations

SUMMARY

Tractor ride vibration levels have been measured when operating with and without a two wheel (2W) unbalanced and a four wheel (4W) balanced trailer. Measurements were made in the vertical, pitch, longitudinal and roll directions with the trailers unladen and laden over four typical farm surfaces

The results showed that tractor ride vibration levels were usually increased in all directions-particularly the longitudinal direction- when operating with the laden trailers. But for the unladen trailers, they were increased only in the longitudinal direction. Predominant tractor frequencies tended to be lower with the trailers attached, and coupling between the tractor longitudinal, vertical, roll and pitch co-ordinates was generally increased

Comparisons of the results with the trends predicted by a simplified theoretical model of a tractor and 2W trailer, suggested that the model should be extended to include, (a) the roll direction, (b) more realistic ground inputs, and (c) a 4W trailer     

Ride Vibration Measurements of Agricultural Tractor and Trailer Combinations

Tractor ride vibration levels have been measured when operating with and without a two wheel (2W) unbalanced and a four wheel (4W) balanced trailer. Measurements were made in the vertical, pitch, longitudinal and roll directions with the trailers unladen and laden over four typical farm surfaces

The results showed that tractor ride vibration levels were usually increased in all directions-particularly the longitudinal direction- when operating with the laden trailers. But for the unladen trailers, they were increased only in the longitudinal direction. Predominant tractor frequencies tended to be lower with the trailers attached, and coupling between the tractor longitudinal, vertical, roll and pitch co-ordinates was generally increased

Comparisons of the results with the trends predicted by a simplified theoretical model of a tractor and 2W trailer, suggested that the model should be extended to include, (a) the roll direction, (b) more realistic ground inputs, and (c) a 4W trailer     

Model-based control of an electropneumatic brake system for commercial vehicles

A properly functioning brake system is critical for ensuring the safe operation of any vehicle on roadways. Commercial vehicles such as trucks, tractors-trailers and buses are equipped with an air brake system that uses compressed air as the energy transmitting medium. This paper presents a model-based control scheme for an electropneumatic brake system for use in commercial vehicles. A mathematical model for an electropneumatic brake system was developed and corroborated with experimental data. A control scheme was developed based on this model and was used to regulate the pressure of air inside the brake chamber according to a desired pressure trajectory. This control scheme was implemented on an experimental test bench, and its performance was studied for various values of the controller parameter. The control scheme was tested for various desired pressure trajectories reflecting actual brake operation.     

Model-based analysis of the mechanical subsystem of an air brake system

Most commercial vehicles such as buses and trucks use an air brake system, often equipped with an S-cam drum brake, to reduce their speed and/or to stop. With a drum brake system, the clearance between the brake shoe/pad and the brake drum may increase because of various reasons such as wearing of the brake shoe and/or brake drum and drum expansion caused by high heat generation during the braking process. Hence, to ensure proper functioning of the brake system, it is essential that the clearance between the brake shoe and the brake drum is monitored. In this paper, we present a mathematical model for the mechanical subsystem of the air brake system that can be used to monitor this clearance. This mathematical model correlates the push rod stroke transients and the brake chamber pressure transients. A kinematic analysis and a dynamic analysis of the mechanical subsystem of the air brake system were performed, and the results are corroborated with experimental data.     

发动机制动、排气制动与缓速器联合作用时的非连续线性控制系统的研究

针对客车发动机制动、排气制动的制动扭矩比较小的问题,提出采用发动机制动、排气制动与缓速器联合作用的持续制动方式,并且针对汽车在山区道路下坡行驶过程中对稳定车速的要求,进行了相应的控制系统设计。模拟分析结果表明:该控制系统可以保证汽车在不采用行车制动器的条件下,利用发动机制动、排气制动与缓速器联合作用的持续制动方式,在各种坡度的坡道上以希望的车速稳定下坡行驶,为汽车在山区道路连续下坡行驶的制动安全性提供了一个合理的解决方案。     

基于混杂理论的电磁与摩擦集成制动方法

鉴于传统电子液压制动系统连续制动易产生"热衰退"现象，结构缺陷导致的制动响应慢，制动系统与电控系统衔接差等缺点，提出了一种基于混杂自动机模型的电磁与摩擦集成制动方法。首先分析集成制动器制动时的工作特点以及不同情况下对应的工作模式（纯电磁制动、纯摩擦制动以及集成制动），并确定3种制动模式的切换条件，通过逻辑门限算法将其实现。根据制动时车辆既具有连续运动状态又有离散状态的混杂特性，使用MATLAB/Stateflow建立基于制动模式切换系统的推广自动机模型，并根据制动模式切换控制策略，对3种制动模式切换进行试验，验证制动模式切换控制策略的合理性。最后选取车辆制动初速度为28 m·s^-1的直线制动工况，分别在高附着系数（0.85）以及低附着系数（0.3）的路面条件下，通过试验平台对控制算法和制动系统性能进行试验验证。研究结果表明：所提出的汽车混杂理论模型以及优化方法在在低附着系数（0.3）路面条件下，集成制动方法较传统液压制动系统缩短5.12%的制动距离，缩短制动时间0.3 s；在高附着系数（0.85）路面条件下，集成制动方法较传统液压制动系统缩短5.66%的制动距离，缩短制动时间0.2 s，能有效提高制动效能。