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附录一在汽车工程中的研究进展：制动辅助差速器锁止系统摘要：“它需要一个汽车组装螺栓至 8460、一个螺母到散布在它所有的路。” 在过去的 10 年中，一些最大的汽车技术领域的研究进展已经出现在汽车安全领域。由于微处理器的速度，缩形技术（miniaturization)、软件开发等技术的 发展的促进，汽车也继续发展。提出了一种新的方法，在这，我计划用一个电 子气动电路自动控制牵引车辆。在普通情况下，当车辆是驱动上下直道，或如 果两个速度之间的差异的（后）轮是在指定的限制之内，信号将不会生成的电 子电路。这将帮助汽车更好的控制差异。但是，如果速度之间的差异是定的超 越极限的信号，将生成的这将启动电路的电子气动电路。这将会逐渐的制动那 个最快的车轮，直到它受到牵引。因此，该轮将不会失去牵引力。对于现在存 在的并已经得到制造公司和最终的消费者成本意识的支持的系统，该系统能确 保减少超过 50%的资本投资。关键词：差速锁，牵引防滑控制差分，气动刹车1. 简介你真的是舒适的操纵你的车走过泥泞的小路吗？在干燥的条件下，当有足够的牵引力，到车轮的扭矩的量是被发动机和传动装置限制；在牵引力较小的情况， 例如当在冰上开车，扭矩的量是有限的最大量，不会造成车轮滑下条件。所以， 即使一辆车可以产生更大的扭矩，需要有足够的牵引力来传递扭矩到地面。只要轮胎抓住路面，提供一种抗旋转力驱动车辆前进即可。传动系统扭矩是均匀分布的两个后轮的驱动桥轴。当一个轮胎的遭遇道路上的滑点，失去牵引力，旋转阻力降低，车轮开始旋转，因为此时抵抗力有所下降，传递到车轮的扭矩变化，并且此时车轮不能被驱动行驶。车辆在这种情况下是静止，只有车轮在滑点旋转，因此，车辆不动。这种情况就是差动齿轮要解决的地方。随着牵引力减少，轮子以非常高的速度转动，产生的热量迅速增加， 润滑油膜破裂，金属金属发生接触，零部件损坏。如果现在轮突然有牵引，突然的冲击能使传动轴损坏严重。所以目前我们如何克服这些困难?为了克服这些问题，不同厂家开发了限滑差速器。在汽车应用，限滑差速器（LSD）是一个修改或衍生式差动齿轮装置，其允许在输出轴的旋转速度差一些， 但是不允许速度的差异增加超出了预置数值。在一辆汽车,这样的限滑差有时被用来代替标准的差异,在这里以更大的复杂性为代价，传达一定的动态优势。一种防滑的主要优势微分是考虑一个标准的情况下（或“打开”）在一轮差有没有联系所有地面。在这种情况下，接触轮将保持固定的，而非接触轮旋转的两倍预期速度传递的扭矩是相等的两车轮，但不会超过扭矩阈值移动车辆，使车辆保持静止。在日常使用的一般类型的道路，这样的情况几乎不可能的，所以正常的差就够了。对于更多使用要求，如驾驶越野车，或高车辆性能，这种状态是不可取的，但 LSD 可以用来处理这种情况。通过限制一对驱动轮之间的速度差，有用扭矩可被传递，只要有一些摩擦提供在至少一个轮子。离合器式 LSD 响应于驱动轴的扭矩。越多的驱动轴输入扭矩，离合器被挤压在一起越困难，因此更密切的驱动轮连接更好。限滑差速器的限制 a）热耗散导致润滑油膜破裂，金属金属接触的情况。b）如果通电离合器摩擦是整个组件损坏，必须拆卸。c）高质量的润滑要求。 D）由于机械大量存在部件，可靠性低。 E）随着车速的增加，车辆的噪声也增加。 f）复杂昂贵。二提出辅助锁止差速器系统在这种新的方法，有一个电子和一个气动回路自动控制车辆的牵引力。在正常情况下,当车辆行驶在直路,或者两个(后)轮子的转动速度之间的差异低于指定的限制,将没有将电子电路产生的信号。这有助于车辆协商更好的牵引力控制系统,微分动作是不变的。但如果速度差超过某一限度，信号由电子电路产生的， 它会启动气动回路。这导致渐进制动的速度直到它获得牵引轮。因此，车轮将永远不会失去牵引。根据输入的传感器数据，在 b ADL s 控制模块检测到车轮对滑，将脉冲常开电磁阀闭合，电路进。同时，该控制模块打开常闭电磁阀这个电路。这导致了气压作用在制动片上，形成人工制动。一旦影响其他轮回到相同的速度， 控制模块返回各自的阀门正常位置释放任何残余压力，消除气动刹车电路的影 响。图 1 示意电路 b ADL s图 2 在 b ADL s 电路工作图 2 BADLS 电路的工作流程图解释图 1 所示电路的工作首先在图 2 上面给出流程图显示了正常的工作打破电路,后者显示了工作时电路工作。在正常的突发状况电磁阀 1 是在封闭条件下,空气从主人绕过辅助缸流在主制动电路电路通过电磁阀 1,因此正常的打破行动是实现。状况下滑单片机常闭电磁阀的启动和常开电磁阀 2,因此人工制动应用于需要的轮子。A. BADLS 控制模块该系统提供了一种控制系统，至少两驱动轮，一个微分传输动力从发动机到驱动车轮，且在驱动轮之间允许相对速度。控制系统包括两个轮速传感器，比较器电路和控制电路。车轮速度传感器被配置为检测两驱动轮角速度和产生的信号。比较器电路耦合到车轮速度传感器并且传感器的配置为比较信号并生成一个代表的驱动车轮的滑移程度的信号。控制电路是耦和比较器电路和制动辅助微分锁定机构，并且被配置为在发生滑动时产生控制信号。三.架构FORBRAKE 辅助微分锁定系统控制电路所示图 3 配置接收代表车辆操作参数的信号(轮子滑动的条件)和生成对应于为了限制两个驱动轮相对速度的制动辅助微分锁机制状态的控制信号。传感器是与后轮相关联的控制逻辑通过不断循环的控制电路的执行确定微分锁定机制基于操作参数的期望状态。控制电路适用于一个适当由微分锁定机制引起的根据理想状态的结合或分离的控制信号。车轮速度传感器配置为检测两个后轮的速度和生成一个轮子速度给定信号作为输入到微控制器。一个比较器的电路耦合到微控制器车轮速度传感器产生代表驱动轮的滑度的信号。一个控制电路耦合比较器电路和微分锁定机制并且配置为当一个预先确定的滑动发生，生成控制信号同时应用微分锁定机制的控制信号来限制应用人工制动驱动电磁阀的驱动轮之间的相对速度控制微分电路进一步配置为当滑动的程度降低且低于预定阈值时脱离锁定机制车轮速度传感器提供为每个驱动轮,每个轮速度传感器被配置为生成轮速度信号和应用车轮速度信号比较器电路,其中控制电路配置为生成控制信号限制驱动车轮滑动时之间的相对速度。四.规范的电子组件 微控制器 模拟到数字转换器 信号调节器1。晶体管2。二极管a. 微控制器使用 BADLS：单片机的输入是两个车轮速度传感器所传输的速度。微控制器获得不同的速度传感器的输出之间的它的最大允许变化的比较。如果变化超出规定值，它可以激活电磁阀，从而使辅助电路，避免任何打滑的车轮b. 电磁阀使用 BADLS：他们作为 ON/OFF 开关和控制加压空气进入副回路流量。型： 滑阀式c. 模拟数字转换器使用 BADLS：从车轮速度的模拟速度信号传感器是由 ADC 转换成数字格式是提供给单片机输入d. 空气制动系统在空气制动的最简单的形式，称为直的空气系统，在气缸内压缩空气推动活塞。活塞连接到制动蹄，可与轮摩擦，使用所产生的摩擦，降低牵引。压缩空气来自一个空气压缩机和被流通的由管道和软管组成的气动线。为了应用制动力， 制动蹄和压缩空气被使用。在一般的空气制动系统包括一个压缩机单元，空气储液罐，制动气室和轮机构。随时保持足够的制动力，即使发动机不运转和空气储罐还是有必要具备的。保持空气压力，这是小的空气泵，使用。压缩机把空气从大气通过滤波和压缩空气送入通过卸荷阀的水库，被解除在一预定的储层压力和减轻压缩机负荷。储层中的空气到各种配件同时也对制动气室也称为膜单元在每一轮，通过制动阀。制动控制阀与司机可以控制强度打破按要求。卸荷阀空气制动系统用于调节管路压力五.测试和评价参数该系统已在巴哈的印度汽车研究协会（协会）测试车测试。这确实帮助巴哈队经常遭遇的类似 SAE 情况打滑的车轮。由于车辆滑移通常是大约 12-15%而转动，单片机的系统的设计是为了活跃在约 20%转动的条件和停用约 5%的滑动。该系统测试成功，下一步将是可行的一些小的修改后的汽车中的实现。车辆被顶起一轮与其他轮落在地面。这样做是为了模拟最大滑移条件。这种情况会出现在实际条件下，如当车辆正在岩石地形时，发动机启动和加速。由于一轮空气中， 车辆没有向前移动，顶车轮旋转过。现在，电磁阀被激活了提供了滑轮和人工制动。六.成本比较表从以上可以看出，此系统确保超过 50%的资本投资减少相较于现有的系统。七.优势A） 可以在车辆气动容易实现制动系统稍作修改。B） 电子电路使用，响应时间，控制和可靠性均优于现有的系统。C） 低级别润滑油可作为热损失减少。 D）最后但并非最不重要的，系统是经济的和简单的。八.局限性整体效率取决于组合效率无论是电子以及气动系统。九.应用该系统可以成功地将车辆气动/液压制动系统，提高牵引。它可以用在特别全地形车（ATV）和车辆的运行在高海拔地区（军用车辆），雪牵引过度流失的原因。该系统确保了超过 50%的资本投资减少相比于现有的系统，保证了“奋进号”的成本效益。致 谢作者感谢 r.b.patil 教授，系主任，陆军技术研究所，印度博士和 KC 埃武拉在印度汽车研究协会（协会），他们的指导和支持。参考文献【1】杰克厄尔贾维克，汽车技术-系统方法（德尔玛汤姆森学习，2000）【2】T.K.加勒特，K. W.牛顿，战马，机动车辆（巴特沃斯 heinmann，2001）附录二Advances in Automobile Engineering: Brake Assisted Differential Locking SystemKanwar Bharat SinghAbstract -“It takes 8,460 bolts to assemble an automobile, and one nut to scatter it all over the road.”Some of the biggest advances in the field of automotive technology in the past 10 years have come in the area of safety.Spurred by the improvements in the microprocessor speed,miniaturization, and software development, the automobile continues to evolve.In this new approach proposed, I am going to have an electronic and a pneumatic circuit to automatically control the traction of the vehicle.During ordinary conditions, when the vehicle is driven down a straight road, or if the difference between speeds of the two (rear) wheels is below a specified limit, no signal will be generated by the electronic circuit. This helps the vehicle negotiate the turns with better traction control as differential action is unaltered. But if the difference between speeds is beyond a specified limit, the signal will be generated by the electronic circuit which will actuate the pneumatic circuit. This causes gradual braking on the faster wheel until it gains traction. Hence, the wheels will never lose traction.This system ensures a reduction of more than 50% in the capital investment as compared to the already existing systems can tilt the scales in the favour of the manufacturing company and eventually the cost conscious consumer.Keywords Differential locking, traction control, Limited slip differential, pneumatic braking.I. I NTRODUCTIONAre you REALLY comfortable manoeuvring your vehicle through a muddy patch?In dry conditions, when there is plenty of traction, the amount of torque applied to the wheels is limited by the engine and gearing; in a low traction situation, such as when driving on ice, the amount of torque is limited to the greatest amount that willnot cause a wheel to slip under those conditions. So, even though a car may be able to produce more torque, there needs to be enough traction to transmit that torque to the ground .As long as the tyre grips the road, providing a resistance to turning, the drive train forces the vehicle forward.Manuscript received March 22, 2008. This work was supported in part by the Automotive Research Association of India (ARAI), pune, India. The Author is with Tata Motors Ltd, pune, India, phone: +919250006237 fax:91 124 2805140 e-mail: Kanwar.singhDriveline torque is evenly distributed between the two rear drive axle shafts by the differential. When one tyre encounters a slippery spot on the road, it looses traction, resistance to rotation drops, and the wheel begins to spin. Because the resistance has dropped, the torque delivered to both the wheels changes. The wheel with good traction is no longer driven. If the vehicle is stationary in this condition, only the wheel over the slippery spot rotates. Hence the vehicle does not move. This situation places stress on differential gears. As the traction fewer wheels rotates at a very high speed, amount of heat generated increases rapidly, lube film breaks down, metalto metal contact occurs, and the parts are damaged. Now if the spinning wheel suddenly has traction, then the shock of the sudden traction can cause severe damage to the drive axle assembly.So presently how do we overcome these difficulties?To overcome these problems, differential manufacturers have developed the Limited Slip Differential. In automotive applications, a limited slip differential (LSD) is a modified or derived type of differential gear arrangement that allows for some difference in rotational velocity of the output shafts, but does not allow the difference in speed to increase beyond a preset amount. In an automobile, such limited slip differentials are sometimes used in place of a standard differential, where they convey certain dynamic advantages, at the expense of greater complexity. The main advantage of a limited slip differential is found by considering the case of a standard (or open) differential where one wheel has no contact with the ground at all. In such a case, the contacting wheel will remain stationary, and the non-contacting wheel will rotate at twice its intended velocity the torque transmitted will be equal at both wheels, but will not exceed the threshold of torque needed to move the vehicle, thusthe vehicle will remain stationary. In everyday use on typical roads, such a situation is very unlikely, and so a normal differential suffices. For more demanding use however, such as driving off-road, or for high performance vehicles, such a state of affairs is undesirable, and the LSD can be employed to deal with it. By limiting the velocity difference between a pair of driven wheels, useful torque can be transmitted as long as there is some friction available on at least one of the wheels. The clutch type LSD responds to drive shaft torque. The more drive shaft input torque present, the harder the clutches are pressed together and thus the more closely the drive wheels are coupled to each other.L imitations of the Limited Slip Differentiala) Heat dissipation leads to lube film breakage, metal- to-metal contact occurs.b) If the friction lining of the energized clutch is damaged, the whole assembly has to be dissembled.c) High quality lubrication required.d) Due to presence of large number of mechanical components, reliability is less.e) As the speed increases, noise of vehicle also increases.f) Complicated and costly.II. PROPOSED INNOVATION-BRAKE ASSISTED DIFFERENTIAL LOCKING SYSTEM (BADLS)In this new approach, there is an electronic and a pneumatic circuit to automatically control the traction of the vehicle. During the ordinary conditions, when the vehicle is driven down the straight road, or if the difference between the speeds of the two (rear) wheels is below a specified limit, no signal will be generated by theelectronic circuit. This helps the vehicle negotiate the turns with better traction control, as the differential action is unaltered. But if the difference between the speeds is beyond a specified limit, the signal will be generated by the electronic circuit, which will actuate the pneumatic circuit. This causes gradual braking on the faster wheeluntil it gains traction. Hence, the wheels will never lose traction. The BADLS control module senses that a wheel is about to slip based on the input sensor data and in turn pulses the normally open inlet solenoid valve closed for that circuit. This allows fluid to enter the circuit. At the same time, the control module opens the normally closedsolenoid valve for that circuit. This leads to the application of pneumatic pressureon the brake pads, leading to the artificial braking. Once the affected wheel returns to the same speed as the other wheel the control module returns both the valves to their respective normal positions releasing any residual pressure in the pneumatic circuit of the affected brake.Fig. 1 SCHEMATIC CIRCIUT OF BADLSFig. 2 WORKING OF THE BADLS CIRCUITFlowchart to explain working of the circuit shown in Fig 1 is given above in Fig 2 First flowchart shows working of normal breaking circuit and the latter shows the working when the badls circuit is working. During normal breaking condition solenoid valve 1 is in closed condition so air from master cylinder flows in main braking circuit bypassing the auxiliary circuit through solenoid valve 1 and thus normal breaking action is achieved. .In slipping condition microcontroller actuates normally closed solenoid valve and normally open solenoid valve 2 and thus artificialbraking is applied to the required wheel.A. The BADLS Control moduleThe system is provided a control system, at least two driven wheels, a differential for transmitting power from the engine to the driven wheels and permitting relative velocity between the driven wheels. The control system includes two wheel velocity sensor, a comparator circuit and a control circuit. The wheel velocity sensor is configured to detect the angular velocity of the two driven wheels and to generate a signal. The comparator circuit is coupled to the wheel velocity sensor and is configured to compare the signals of the sensors and to generate a slip signal representative of the degree of slip of the driven wheels. The control circuit is coupled to the comparator circuit and to the brake assisted differential locking mechanism and is configured to generate control signals when a predetermined degree of slip occurs and to apply the control signals to the differential locking mechanism to limit relative velocity between the driven wheels.III. PROPOSED ARCHITECTURE FORBRAKE ASSISTEDDIFFERENTIAL LOCKING SYSTEMThe control circuit shown below in Fig.3 is configured to receive signals representative of vehicle operating parameters (condition of slipping of wheels) and to generate control signals corresponding to the desired state of the brake assisted differential locking mechanism for limiting relative velocity between two driven wheels. Sensors are associated with the rear wheels. Control logic executed by the control circuit in a continuously cycled routine determines the desired state of theFig. 3 PROPOSED ARCHITECTURE OF SYSTEMdifferential locking mechanism based upon the operating parameters. The control circuit applies an appropriate control signal to the differential locking mechanism causing engagement or disengagement in accordance with the desired state. Wheel velocity sensor are configured to detect the velocity of the two rear wheels and to generate a wheel velocity signal given as an input to the micro controller. A comparator circuit of the micro controller is coupled to the wheel velocity sensors generate a slip signal representative of the degree of slip of the driven wheel. A control circuit is coupled to the comparator circuit and to the differential locking mechanism and configured to generate control signals when a predetermined degree of slip occurs and to apply the control signals to the differential locking mechanism to limit relative velocity between the driven wheels by applying artificial braking by actuating the solenoid valves. The control circuit is further configured to disengage the differential locking mechanism when the degree of slip decreases to a level below a predetermined threshold. Wheel velocity sensor is provided for each of the driven wheels, each of the wheel velocity sensors being configured to generate wheel velocity signals and to apply the wheel velocity signals to the comparator circuit, and wherein the control circuit is configured to generate control signals for limiting relative velocity between the driven wheels when slip of any driven wheelexceeds apredeterminedthresholdvalue .IV. SPECIFICATIONS FOR ELECTRONIC COMPONENTS MICRO CONTROLLER ANALOG TO DIGITAL CONVERTER SIGNAL CONDITIONER1. Transistor2. DiodeA.MICROCONTROLLERUSE IN BADLS: The microcontroller input is the speed of the two wheel speed sensors. The microcontroller obtains the difference in between the two speed sensor outputs and compares it with the maximum allowable variation. If the variation is beyond the stipulated value, it activates the solenoid valves, thus enabling the auxiliary circuit, avoiding any slipping of the wheels.B.SOLENOID VALVEUSE IN BADLS: They act as ON/OFF switches and control flow of pressurized air into the Auxiliary Circuit. TYPE: Spool TypeC.ANALOG TO DIGITAL CONVERTERUSE IN BADLS: the analog speed signal from the wheel speed sensors is converted into the digital format by the ADC which is supplied as the input to the microcontrollerD. AIR BRAKING SYSTEMIn the air brakes simplest form, called the straight air system, compressed air pushes on a piston in a cylinder. The piston is connected to a brake shoe, which can rub on the wheel, using the resulting friction to slow the train. The pressurized air comes from an air compressor and is circulated by a pneumatic line made up of pipes and hoses. In order to apply the braking force to the brake shoes, compressed air isused. An air brake system in general includes a compressor unit, air-reservoir tank, brake chamber and wheel mechanism. For maintaining adequate braking force at all times even when the engine is not running and air-reservoir tank is also necessary. To maintain air pressure, which is small air pump, is used. The compressor takes air from the atmosphere through the filter and the compressor air is sent to the reservoir through the unloader valve, which gets lifted at a predetermined reservoir pressure and relieves the compressor load. From the reservoir the air goes to the various accessories and also to the brake chambers also called the diaphragm units at each wheel, through the brake valve. The control of brake valve is with the driver who can control the intensity of breaking according to the requirements. The unloader valve in the air breaking system serves to regulate the line pressure.V. TESTING AND EVALUATION PARAMETERSThe system has been tested on a SAE BAJA test vehicle at the Automotive Research Association of India (ARAI), pune. This was done keeping in mind that this application would be really helpful for SAE BAJA teams who encounter conditions like slipping of wheels very often. Since vehicle slip is usually about 12-15% while turning, this microcontroller of the system has been designed to active at about 20% slip conditions and deactivates at about 5% slip. The system was tested successfully and the next step would be practical implementation in automobiles after some minor modification. The vehicle was jacked up on one wheel with the other wheelresting on ground surface .This was done to simulate the condition of maximumslipping. This condition will be present in actual conditions when vehicle is negotiating rocky terrain. The engine was started and accelerated. Due to one wheel being in air, the vehicle did not move for