基于S3C2410X的车辆制动监测装置研制

根据车辆104空气制动机的参数特征,研制了一种基于S3C2410X处理器的车辆制动系统监测装置,该装置可实现车辆制动系统常见故障的检测,并对检测结果及制动系统状态数据进行大容量存储,实现对制动机维护的计算机管理。监测装置由气体压力传感器和32位嵌入式计算机两部分组成。压力传感器检测列车制动管、制动缸和工作风缸的压力值。嵌入式计算机通过对传感器提供的信息进行分析处理,实现故障的判别、显示和报警。在单车试验台上进行了车辆制动机故障模拟试验,实验结果表明,该监测装置能够实现常见制动故障的实时检测和报警。     

装甲车辆传动装置试验台无损连接制动系统研究

传动装置试验台无损连接制动系统是传动装置试验台大转矩原位校准系统的重要组成部分,可实现对装甲车辆大转矩传动轴的无损连接制动.为了在满足现场空间要求的前提下保证原位校准的准确性,本文设计了一套与现场大转矩动力输出装置相匹配的无损连接制动系统.该系统不仅适用于现场狭小空间,而且可根据传动装置试验台输出转矩的大小提供与之匹配...     

厚壁金属管挤压变形缓冲制动响应特性研究

金属管挤压变形是高效缓冲制动的重要形式,但目前对不同结构形式在动态冲击条件下的响应特性缺少系统的认识;以厚壁金属管为对象,对其挤压变形缓冲制动响应进行数值研究。参照试验状态和结果建立厚壁金属管缓冲制动装置的有限元分析计算模型,进行准静态仿真模拟分析并校核;在此基础上利用有限元法和显示动力学算法,对厚壁金属管缓冲制动响应特性以及影响缓冲力的主要因素进行研究和分析。结果表明:①厚壁金属管缓冲制动结构具有尺寸小、冲击载荷平稳、变形能力强的特点;②利用此计算模型能够清晰地表征厚壁金属管缓冲制动装置的动态响应;③影响缓冲力大小的主要结构因素是缓冲筒下部内孔直径、上部内孔直径以及外部直径,缓冲筒上下内径比D1应控制在0.7~0.8,D2应控制在1.8~2.0,当比值越小时,冲击杆会出现反冲现象,当比值越大时,冲击杆受到较大的冲击力,缓冲筒的惯性制动段的制动也有较大波动的影响。针对工程应用中不同的缓冲制动需求,可以通过设置合理的缓冲筒内外廓直径参数来获得有效的制动载荷。可为相关研究和工程应用提供参考。     

Dynamic characteristics of hydraulic brake devices with magnetorheological control

Consideration is given to the magnetorheological principle of control of an electrohydraulic brake device. The level of dissipation losses in the channel of the control unit, which determines the braking force in such systems, is regulated by a magnetic field adjusting a magnetosensitive pressure fluid to a prescribed effective viscosity. In an experiment, control of the main parameters characterizing the force and frequency characteristics of the device has been accomplished. It is found that the characteristic time of developing a braking force is 10⁻³ sec, and the speed of response of the system is mainly limited by the frequency characteristics of the inductor of the magnetic field of the magnetorheological throttling valve. Academic Scientific Complex “A. V. Luikov Heat and Mass Transfer Institute,” National Academy of Sciences of Belarus, Minsk, Belarus. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 72, No. 5, pp. 874–880, September–October, 1999.     

超深矿井提升机制动盘热性能分析与优化

超深矿井提升机制动盘在紧急制动过程中由于受到摩擦循环热载荷的作用，内部产生较大的热应力，同时高温会导致制动盘和闸片摩擦制动性能下降甚至失效。针对制动盘制动热性能问题，根据热传导理论和有限元分析方法，建立了制动盘组件三维有限元模型，采取直接耦合方法对制动盘制动过程中的热应力场进行模拟研究，并通过实验验证了仿真参数设置的正确性。分析了闸片数量和排布方式对制动工况下制动盘温度和应力分布的影响。结果表明，在制动阶段，制动盘摩擦面温度先急剧上升，后缓慢下降，摩擦面温度呈现锯齿状波动性变化，制动过程中应力变化规律与温度变化规律相同。原制动盘在制动过程中的最高温度为134.8℃，最大应力为230.2 MPa，高温和大应力区域集中于摩擦面附近；增加闸片数量的制动盘最高温度为142.4℃，最大应力为251.1 MPa，高温和大应力区域同样集中于摩擦面附近；改变闸片排布方式的制动盘最高温度为86.5℃，最大应力为119.1 MPa，高温区域和大应力区域范围较小。由此可知，改变闸片排布方式更能显著降低制动盘温度和应力，并且温度场和应力场分布更均匀。研究结果可为制动盘热性能优化设计提供理论参考。     

Thermomechanical Behavior of Brake Drums Under Extreme Braking Conditions

Braking efficiency is characterized by reduced braking time and distance, and therefore passenger safety depends on the design of the braking system. During the braking of a vehicle, the braking system must dissipate the kinetic energy by transforming it into heat energy. A too high temperature can lead to an almost total loss of braking efficiency. An excessive rise in brake temperature can also cause surface cracks extending to the outside edge of the drum friction surface. Heat transfer and temperature gradient, not to forget the vehicle's travel environment (high speed, heavy load, and steeply sloping road conditions), must thus be the essential criteria for any brake system design. The aim of the present investigation is to analyze the thermal behavior of different brake drum designs during the single emergency braking of a heavy-duty vehicle on a steeply sloping road. The calculation of the temperature field is performed in transient mode using a three-dimensional finite element model assuming a constant coefficient of friction. In this study, the influence of geometrical brake drum configurations on the thermal behavior of brake drums with two different materials in grey cast iron FG200 and aluminum alloy 356.0 reinforced with silicon carbide (SiC) particles is analyzed under extreme vehicle braking conditions. The numerical simulation results obtained using FE software ANSYS are qualitatively compared with the results already published in the literature.     

基于TRIZ理论的输送带断带保护装置创新设计

目的 在运输物品过程中,输送带因长时间使用可能会发生断裂现象,目前断带保护装置无法及时进行保护,因此需要对断带保护装置进行改进。方法 应用TRIZ理论中的功能模型分析和因果链分析方法对整个系统进行分析,应用76条标准解、发明原理和分离原理等工具解决问题。结果 基于TRIZ理论对问题进行求解,得到了新型输送带断带保护装置的结构方案,该方案可以有效缩短断带保护所需时间,有效提高断带保护的精准性,从而保护生命财产的安全。结论 通过TRIZ理论对输送带断带保护装置进行创新设计,使新型输送带断带保护装置达到了快速反应、制动精准和结构简单的要求。     

Low‐Frequency Eddy Currents and Dissipative Processes under the Conditions of Magnetic Abrasive Treatment

The questions of generation of eddy currents for a rotating cylindrical metallic part in magnetic abrasive treatment have been considered analytically. The power of dissipative electromagnetic forces and the effective braking torque have been calculated in the approximation of a normal skin effect on the basis of macroscopic field equations with the use of the model condition of axial symmetry for an electric field and the dispersion relation.     

履带车辆紧急制动动力学仿真分析

摘 要：基于虚拟样机技术,用ADAMS/ATV模块建立了某型履带车辆的紧急制动动力学模型。通过实车的行驶试验和紧急制动试验对模型进行了VV&;A验证,结果表明所建动力学模型在反映履带车辆行驶及紧急制动动力学行为方面能够满足工程分析的需要。将其作为分析平台,对履带车辆进行了紧急制动动力学仿真分析,分析了3-6档平均车速下紧急制动的动力学响应;并通过紧急制动仿真实验得到了履带车辆的制动特性图。     

智能压力检测系统测量精度设计与分析

在对机车制动系统的压力信息在线监测必要性后，根据机车运行过程中制动系统在各工况下的实际工作情况。从理论上计算分析了压力检测系统必需达到的检测精度，以理论计算结果作为设计依据，对压力检测系统各环节的误差进行计算与分配，并根据计算结果对压力检测系统中各构成环节进行参数设计和元器件选择。实验结果表明根据各环节误差分析结果设计的系统的检测精度达到了设计要求。     

鼓式制动器制动不稳定时变特性分析

由于工作环境复杂多变,制动器工作不稳定而导致振动和噪声,鼓式制动器制动时的温度变化对制动不稳定性影响较大,研究制动不稳定性影响因素及其制动不稳定时变特性具有实际工程意义。基于鼓式制动器四自由度接触模型,分别在Hypermesh和ABAQUS中建立鼓式制动器制动鼓和制动蹄总成模型与摩擦制动接触模型并进行试验验证;通过热机耦合动态分析,研究制动鼓温度对制动应力的影响;分析弹性模量和热膨胀系数对鼓式制动器制动不稳定时变特性的影响。分析表明：制动不稳定性是摩擦力耦合所致;制动过程中制动鼓温度与应力相互作用且均先快速上升后缓慢下降;鼓式制动器制动不稳定时变特性主要体现在不稳定模态个数及不稳定倾向系数（tendency of instability, TOI）值的变化,制动温度变化导致弹性模量变化,引起不稳定模态个数和TOI值略有变化,弹性模量对鼓式制动器制动不稳定时变特性影响较小;制动温度变化导致热膨胀系数变化,引起不稳定模态个数和TOI值先大幅降低后略有升高,热膨胀系数对鼓式制动器制动不稳定时变特性影响较大。研究结果对改善汽车制动声品质具有一定指导意义。     

Non-uniformity in braking in coaching and freight stock in Indian Railways and associated causes

Non-uniform braking of wheel sets in locomotives and coaches/wagons can have disastrous consequences e.g. from wheel locking leading to derailments or thermal cracking, particularly under emergency braking conditions. Currently, while rigorous testing is used to characterize brake block characteristics and brake application time, no methods exist to determine the “variability” in braking across the different wheel sets, e.g. from differences in brake block characteristics, brake rigging, and performance of distributor valves. In this work, temperature rise in railway wheels is used to gauge normalized heat input coming in to wheels from braking. Two sets of field trial data are used to investigate variability of braking: (i) continuous rim temperature data for locomotive wheels and (ii) one time measurement of wheel rim temperatures of all wheels. The data is used to pin point the causes for non-uniformity in braking and to characterize the extent of non-uniformity. Non-uniformity in braking is found to be particularly severe in freight trains as compared to passenger trains. Faulty distributor valves are seen to result in maximum braking effort on wheels that is as high as seven times that of average braking effort in freight trains.     

Analysis of the stability of PTW riders in autonomous braking scenarios

While fatalities of car occupants in the EU decreased remarkably over the last decade, Powered Two Wheelers (PTWs) fatalities still increase following the increase of PTW ownership. Autonomous braking systems have been implemented in several types of vehicles and are presently addressed by research in the field of PTWs. A major concern in this context is the rider stability. Experiments with volunteers were performed in order to find out whether autonomous braking for PTWs will produce a greater instability of the rider in comparison to manual braking. The PTW's braking conditions were simulated in a laboratory with a motorcycle mock-up mounted on a sled, which was accelerated with an average of 0.35 g. The motion of the rider was captured in autonomous braking scenarios with and without pre-warning as well as in manual braking scenarios. No significant differences between the scenarios were found with respect to maximum forward displacement of the volunteer's torso and head (p < 0.05). By performing clustering analysis on two kinematic parameters, two different strategies of the volunteers were identified. They were not related to the braking scenarios. A relation of the clusters with the initial posture represented by the elbow angle was revealed (p < 0.05). It is concluded that autonomous braking at low deceleration will not cause significant instabilities of the rider in comparison to manual braking in idealized laboratory conditions. Based on this, further research into the development and implementation of autonomous braking systems for PTWs, e.g. by extensive riding tests, seems valuable.     

Locomotive wheel failure from gauge widening/condemning: Effect of wheel profile,brake block type,and braking conditions

A finite element model accounting for heat partitioning at brake block–wheel and rail–wheel interfaces is used to investigate the effect of locomotive wheel profile, wheel diameter, brake block type, nature of braking (independent, synchronized, and drag), braking frequency and braking cycles on wheel gauge for tread braked, locomotive wheel sets. A train running model estimates heat generation rates during braking for assumed operating and braking conditions. Wheel profiles and brake block types used in the work, match with that used by Indian Railways. Bending at hub–disc and disc–rim interfaces is seen to primarily control axial deflection of wheels. While gauge reduction is observed during braking, gauge increase is seen during subsequent cooling. Maximum gauge increase occurs as the wheels finally cool down to room temperature. S-shaped wheels are seen to be better suited than straight plate and parabolic profile wheels for avoiding excessive gauge change. Locomotive wheel failure from gauge widening and condemning, albeit at different times, is seen to occur with independent braking for locomotives fitted with straight plate, S-shaped as well as parabolic profile wheels.     

制动器动态特性的仿真研究

采用ADAMS建立双块式电磁制动器的动力学仿真分析模型,并对其进行模拟仿真,产生制动臂在制动过程中各个方向的加速度时域图。经过对各种曲线图的比较,明确在制动过程中弹簧的刚度系数、制动时间以及制动臂振动之间的相互关系。     

Locomotive wheel failure from gauge widening/condemning: Finite element modeling and identification of underlying mechanism

Gauge change in straight plate, locomotive, railway wheels is studied using finite element analysis. The study accounts for residual stresses generated during wheel manufacturing and fitment of the wheel on locomotive axle. A validated thermal model accounting for heat loss to rail, brake blocks and ambient air is considered for accurate prediction of wheel temperatures for a given train running and braking history. Results are obtained for low- and high-friction, composite brake blocks used by Indian Railways for two limiting braking scenarios: (i) synchronized braking where braking effort is uniformly distributed on all brake blocks and (ii) independent braking where braking effort to decelerate a train is provided solely by locomotive brake blocks. Results show that bending at hub–disc interface predominantly governs the gauge change. While compressive hoop stresses in the tread region, occurring from rim heating during braking, cause gauge reduction, tensile hoop stresses in the tread region, occurring during wheel cool down cause an increase in wheel gauge. Importantly, while gauge condemning is a transient phenomenon occurring only during braking, gauge widening is “permanent” as it exists even after the wheels cool to room temperature. Allowable reduction of wheel gauge of 0.5 mm, currently used by Indian Railways, is found to be highly restrictive. In fact, in service wheel failure based on this criterion is observed in all braking scenarios considered.     

Predictive Control Algorithm for Urban Rail Train Brake Control System Based on T-S Fuzzy Model

Urban rail transit has the advantages of large traffic capacity, high punctuality and zero congestion, and it plays an increasingly important role in modern urban life. Braking system is an important system of urban rail train, which directly affects the performance and safety of train operation and impacts passenger comfort. The braking performance of urban rail trains is directly related to the improvement of train speed and transportation capacity. Also, urban rail transit has the characteristics of high speed, short station distance, frequent starting, and frequent braking. This makes the braking control system constitute a time-varying, time-delaying and nonlinear control system, especially the braking force changes directly disturb the parking accuracy and comfort. To solve these issues, a predictive control algorithm based on T-S fuzzy model was proposed and applied to the train braking control system. Compared with the traditional PID control algorithm and self-adaptive fuzzy PID control algorithm, the braking capacity of urban rail train was improved by 8%. The algorithm can achieve fast and accurate synchronous braking, thereby overcoming the dynamic influence of the uncertainty, hysteresis and time-varying factors of the controlled object. Finally, the desired control objectives can be achieved, the system will have superior robustness, stability and comfort.     

湿喷机液压制动系统制动阀性能研究

为了研究串联式双回路液压制动阀对湿喷机制动性能的影响,根据制动阀结构及工作原理,考虑稳态液动力等非线性因素,采用键合图理论建立了液压制动系统的动力学模型,基于MATLAB平台仿真分析了制动阀的静、动态特性,并在湿喷机上搭建实验平台进行其制动性能测试。结果表明：制动阀输出压力具有比例特性,后桥制动响应快于前桥,且后桥制动压力约大于前桥制动压力0.2 MPa;制动阀双段制动压力梯度的设计可以满足湿喷机在高低速行驶时动能差别较大的制动需求;制动阀阶跃响应迅速,系统能在0.3 s内趋于稳定,且无明显压力超调,制动性能稳定;在制动阀复位阶段,制动油缸将工作腔油液迅速排入油箱,解除制动。制动压力的测试值与仿真值基本吻合,验证了所建模型的准确性。研究结果可以为制动系统的参数匹配和制动阀结构优化提供参考。     

Basis of conditions of braking of a flywheel of fiber composite material based on criteria of strength

A ring-type superflywheel with shell and chord windings under the action of the inertial forces of rotation and braking is considered. The condition of braking is represented as a quasisteady process. A network model of the composite was used. The problem is solved for large deformations. A solving system of equations determining the stressed and strained state of the flywheel is given. Examples are given of calculation of the braking conditions of shell and chord flywheels for two variations of boundary conditions corresponding to the methods used for fastening the filament in the area of the polar hole. With the limitations of the braking process with respect to tensile and compressive strength of the filament material the minimum braking time of the flywheel was determined.Translated from Problemy Prochnosti, No. 6, pp. 70–72, June, 1991.     

双线圈旁置式新型磁流变制动器的设计与优化

为提高传统单线圈混合式磁流变制动器的制动力矩,提出了一种双线圈旁置式新型磁流变制动器.利用一种新的线圈安装方式,增大了制动盘圆柱面的可控作用面积,从而增大了磁流变制动器的制动力矩.基于Herscher-Bulkley模型,提出了双线圈旁置式磁流变制动器的力矩模型与磁路设计方法,并在特定条件下对其进行了多目标优化.研究结果表明:与单线圈混合式相比,在相同体积条件下,双线圈旁置式能产生更大的制动力矩;而为了充分利用磁流变液的流变性能,获得更紧凑的结构,双线圈旁置式磁流变制动器的宽度应在80~100mm之间,长宽比的合理范围应在0.6~1.2之间;优化后在制动器质量基本维持不变的情况下,制动力矩提高了11%.研究结果可作为磁流变制动器的设计参考.