电制动器制动力的计算方法

电制动器制动力的计算 电制动器制动力的计算 SAE 1999-01-0482 摘要: Continental Teves (欧洲ITT汽车公司的前身) 和Darmstadt 工业大学正联合开发一种不需要以制动力、制动转矩作为反馈低成本电制动系统的控制策略。然而，由于机电化制动系统中齿轮效率变化范围很大，致使这项工作非常棘手。 这篇文章首先描述了Continental Teves公司的第三代制动器的装置和运行，他们仍然使用了一个集成的制动力传感器，并介绍了Darmstadt工业大学的开发环境，包括一个制动器测试台、一个复杂的制动器模型和一个简化的制动器模型。并对可从制动器上获取的两个信号——电机转子位置和电机电流作了仔细分析，就可能应用的制动力算法讨论了其利弊。 基于制动器的简化模型和信号分析，介绍了只从转子位置和电机电流角度对制动力进行优化的算法。为了能在不同力传感器下调整间隙，我们研究了一种检测制动片和制动盘接触点的算法。 第一个制动力计算和间隙处理的实验结果也在文章中作了介绍。 介绍: 现在登记注册装有ABS、TCS、EPS等现代电子控制系统的汽车数量在不断增多。然而，要在普通的液力制动系统中融入这些功能，却需要大量的电液元件。近年来，汽车工业界和许多生产厂家都因此而在开发电制动系统。目前，有两种构想广为接受，一种是电液系统，另一种是纯机电系统，电液系统仍然使用了制动液和常规的制动器，但引用了一些比例阀。据预测，这种系统将在市场上作为首选。 然而，随着电液制动系统(制动液、制动电路、比例阀等)弊端的出现，纯机电制动系统就成为一种很有前景的构想，而且值得去深入研究。 这项工作的重心就在于在车辆制动器上实现产生制动力的纯机电系统。 图1 图1像我们展示了Continental Teves公司研究的机电制动器，用一种理想的方法使机电系统将一个电子信号值转化为制动力，或是一个作用于制动器的外力。在这一套硬件系统中可以实现常规的和先进的制动功能，控制单元的软件模式和传感装置就决定了电制动系统的功能。 减少汽车硬件和整个系统的重量并不是开发纯电制动系统的唯一动因所在，还由于它不需制动液且很少需要维修(只有制动块和制动盘)。它的分离式的制动踏板可以被安装在既防撞又不占用乘客空间的地方。由于对踏板特点的设计没有什么约束，所以人机和安全就很容易考虑和实现。这种“即插即用”的构想采用了尽可能少的部件降低了生产和后勤的花费。 然而，电制动系统也有些不足。其一就是就是由于恶劣的工作条件和磨损造成制动器效率的不断变化，见图3。每一个子系统，比如机电驱动器、齿轮单元摩擦制动器及轮/路/车系统传输的特性参数变化范围都很大。因此，一个独立的车轮制动器必须在一个闭环控制系统下工作。对盘式制动器来说，一个很明显的需要控制的参数就是制动力[参阅参考文献[8]。然而一个力传感器是很难集成到电制动系统中的，价格昂贵且需要独立标度。 solicited opinions and suggestions Article 265, including: four problems to 171. Deepening special regulation, State line State modified, side check side modified, total solution highlight problem 19 a; to rectification spirit carried out party political life, in-depth carried out heart talk, serious carried out criticism and self-critical; put built chapter State business throughout activities always, full cleanup and established perfect a involved "four wind" aspects of system provides, new 12 items, amendment perfect 15 items, abolition 3 items. Through educational practices, "four winds" problem significantly curb, party members and cadres ' apparent change of consciousness and ability of serving the masses increased significantly. (C) to promote the sustained and healthy development of economy and society. Adhere to the "party-led township, prospering Township, eco-village, projects promoting Township and industrial Township, industry-rich Township, harmony Township, stabilization control" development strategy, take economic construction as the Center, strengthen leadership over the economic work in earnest, closely around the target determined earlier this year to deal with and try to resolve the various adverse factors, pay close attention to the work. Efforts to promoting the construction of major projects. To transportation, water conservancy, urban infrastructure construction, focusing on implementation of a number of industrial structure adjustment and optimization and upgrading of key projects for leading roles; Completed has XX village pass village Highway, and township location lights bright of, and XX meters "beautiful village", and township public rental and Xiang hospitals public rental, and 270 sets rural housing room 这篇文章对所用的社机电驱动制动器介绍了一种新颖的构想，一种不太传统的方法——不采用力传感器。为了这一目的，首先讨论了在已经可以实现的量，分别建立了一个复杂的和简化的制动器模型。基于简化模型和信号分析，我们想出了一种仅从电机电流和转子位置来计算制动机构效率的方法。计算得到的效率可用于调整制动机构模型。通过调整好的制动模型，就可以算出制动力。 为了在不使用力传感器条件下检测和调整空间间隙，引入了一种基于电机信号的方法。 模拟结果和首次试验结果明了这些方法的应用潜力。 开发环境: 开发过程中的一个主要问题就是创造一个使灵活快速算法得以实现的环境。以下的三套环境皆为开发制动力算法和计算处理所建: . 拥有配置了单轮模型的可加热制动盘的测试台 . 复杂的机电制动盘模型 . 简化的机电制动盘模型 车轮模块——一个由一个配有伺服放大器的机电制动器和微控制单元组成的车轮模型，见图2。 为了使用适于大批量生产的零部件，采用一个16位微控制器作为数控计算的控制平台。微控制器对制动力和位置进行控制、处理间隙并对负责车轮模块的信号传输和监控。 为了驱动车轮制动器的无刷电机，采用一个结构紧凑功能强大的伺服放大器。他对分解器所提供的电机转子位置进行处理，以实现电子信息的传输。另外，伺服放大器还有两个模拟控制器，一个电机电流控制器和一个转子转速控制器。 由机电转换器、齿轮、摩擦制动片及传感器所组成的“智能化盘式制动器”的设计重量轻、结构紧凑的思路下完成的。基于可靠已成功应用的FN制动片，Continental Teves 公司开发了一种结构非常紧凑的电制动器，参考文献1给出了Continental Teves的第二代制动驱动器。见图4给出的是配有附加行星齿轮、制动力传感器及其他调整装置的第三代制动驱动器。 推动内部制动块的不再是活塞，而是主轴。行星转子齿轮的螺帽是由无刷转矩电机通过行星齿轮驱动的。通过把伺服电机的线圈直接嵌入制动器壳内并只用一个中心轴承支撑齿轮单元，就使结构紧凑成为了可能。然而，中心轴承就同时受到径向和轴向力。分解器用以测量转子的位置以传输电信号。 为了对当前Continental Teves公司机电制动器进行制动过程控制和对制动力的变化进行计算，Darmstadt 工业大学开发了一种集成于主轴的力传感器，如图5所示。主轴为传感器的安装提供了很好的条件，它承受了所有的制动力，保护了传感器不受外界恶劣环境影响，并使之在制动过程中不发生转动。 为了估算开发的主轴力传感器的性能，我们将另外一个制动力传感器(装在外部制动片和制动块之间)的输出信号与主轴力传感器的输出作了对比。制动盘在工作过程中可能会加热到不同的温度，而外部的制动力传感器则为了避免高温疲劳而采用水冷处理，图6就向我们展示了传感器的测试结果，对角线状的曲线显示了内部制动力传感器所测的制动力的变化，较低的一组曲线就显示了不同温度下的相对误差。由图可知相对误差非常小，而且没有出现高温疲劳。? 测试台——制动器测试台如图7所示，他是为了达到开发与测试灵活计算的目的而建的。在这个软件中绝大多数变化可以实现与测试，而不需要真车驱动测solicited opinions and suggestions Article 265, including: four problems to 171. Deepening special regulation, State line State modified, side check side modified, total solution highlight problem 19 a; to rectification spirit carried out party political life, in-depth carried out heart talk, serious carried out criticism and self-critical; put built chapter State business throughout activities always, full cleanup and established perfect a involved "four wind" aspects of system provides, new 12 items, amendment perfect 15 items, abolition 3 items. Through educational practices, "four winds" problem significantly curb, party members and cadres ' apparent change of consciousness and ability of serving the masses increased significantly. (C) to promote the sustained and healthy development of economy and society. Adhere to the "party-led township, prospering Township, eco-village, projects promoting Township and industrial Township, industry-rich Township, harmony Township, stabilization control" development strategy, take economic construction as the Center, strengthen leadership over the economic work in earnest, closely around the target determined earlier this year to deal with and try to resolve the various adverse factors, pay close attention to the work. Efforts to promoting the construction of major projects. To transportation, water conservancy, urban infrastructure construction, focusing on implementation of a number of industrial structure adjustment and optimization and upgrading of key projects for leading roles; Completed has XX village pass village Highway, and township location lights bright of, and XX meters "beautiful village", and township public rental and Xiang hospitals public rental, and 270 sets rural housing room 1试。在图7 的右侧，用一个原有的轮轴来支撑制动盘和机电制动器?，制动力传感器信号由一个频率运载放大器采集处理。制动盘上装有五个加热线圈和一个温度传感器。通过加热器控制单元，制动盘能被加热到800?，这样，就可以模拟参数变化并对机电制动器传输特性的影响进行研究。 图7，制动盘可加热的机电盘式制动器测试台 用一个配有Transputer数据采集台的486芯片作为在线测量系统。从一个非常友好的用户控制界面可以看到12个模拟信号输入通道和4个模拟信号输出通道，并以2KH的频率进行采样。桌面采用MATLAB编写，以确保在制动器模拟 6环境下数据便于携带。采用一个可测量相位的电流测量仪?测量电机及电池的相位电流。微控制器及伺服放大器装在一个盒中。 第二个PC是用RS232接口下载和调整在RAM和EEPROM的算法。 复杂的制动器模型——参考文献1中给出了Continental Teves公司的第二代机电制动器。根据模块设计，这一模型很容易改进到第三代。新的参数是分开设计下零件厂商在不同测试台上进行测量确定的。模型是在PC奔腾Pro200机上用MATLAB/SIMULINK模块中实现的，见图8。 图8 盘式制动器模型的SIMULINK模块图 微控制器模块包含了力和唯一传感器，二者具有一定的比例关系，他们的参数可以直接由微控制器软件获取。 在模拟控制块中，考虑了伺服放大器的速度和电流控制器。速度控制器是一个PI控制器，而电流控制器是一个串接的第一级滞后元件。它们在外环与速度控制器串接，见参考文献,,,( 图8模块结构图中下一个模块是电机。为了简化，数据无刷电机可建模为一个的数控电机，其输出扭矩Tm是和电机电流Im成正比的: Tm,Im，, 为了确认电机参数，我们建了一个测试台，让电机以任意选择的扭矩运行。通过电机在不同扭矩下运行及测量电机电流Im，就可以由曲线斜率测出磁通量ψ。 单独的制动器元件的转动惯量和质量可以由CAD程序测出。比如，为了得出电机子系统的转动惯量，电机的分离器、轴承球及转子的转动惯量都得加上。 如图9，行星齿轮可建模为两个串接得齿轮单元。第一个齿轮单元是中心轮单元，第二个是行星架单元。每个支承单元都得考虑支承摩擦和及由齿TTFB1FB2 Cd牙摩擦。每一个齿轮单元的刚度和阻尼都以和表示。为了计算惯性和TGGFT 摩擦损失，要特别注意各元件之间的速度比，在元件供应商的帮助下，所有的参数都可以测量出来。图10 描述了一个齿轮单元的双质量模型。 一项最富挑战性的工作就是PRG(行星滚动轮子系统)的设计。PRG可建模成一个支承件，由于其螺帽,转子及芯轴,转子接触而具有摩擦的双质量振子。由于行星滚动轮的线面接触线与螺帽,转子及芯轴,转子一样，其角接触的轮廓和角接触球轴承相同，因此，模型的摩擦损失可由参考文献,11,中提供的轴承模型解出.最重的PRG子系统应包括以下几部分(见图11): 螺帽、主轴、滚子的刚度(综合考虑为一个刚度和一个阻尼) , solicited opinions and suggestions Article 265, including: four problems to 171. Deepening special regulation, State line State modified, side check side modified, total solution highlight problem 19 a; to rectification spirit carried out party political life, in-depth carried out heart talk, serious carried out criticism and self-critical; put built chapter State business throughout activities always, full cleanup and established perfect a involved "four wind" aspects of system provides, new 12 items, amendment perfect 15 items, abolition 3 items. Through educational practices, "four winds" problem significantly curb, party members and cadres ' apparent change of consciousness and ability of serving the masses increased significantly. (C) to promote the sustained and healthy development of economy and society. Adhere to the "party-led township, prospering Township, eco-village, projects promoting Township and industrial Township, industry-rich Township, harmony Township, stabilization control" development strategy, take economic construction as the Center, strengthen leadership over the economic work in earnest, closely around the target determined earlier this year to deal with and try to resolve the various adverse factors, pay close attention to the work. Efforts to promoting the construction of major projects. To transportation, water conservancy, urban infrastructure construction, focusing on implementation of a number of industrial structure adjustment and optimization and upgrading of key projects for leading roles; Completed has XX village pass village Highway, and township location lights bright of, and XX meters "beautiful village", and township public rental and Xiang hospitals public rental, and 270 sets rural housing room PRG轴向附加载荷所产生的库仑摩擦 T,FR PRG的死区 , 螺帽的转动惯量、转子的转动惯量、滚子的转动惯量及主轴质量,,,,,RK 和振子质量(综合考虑为一个质量和一个转动惯量) mmS, 图11 行星滚动轮 图12 摩擦制动的模型 如图12，在摩擦制动器子系统中，制动片的静态及动态行为、制动块及制 动盘都建立了模型。制动片刚度由一个特别设计的测量单元决定。采用了一台通用机器对串接放松的新制动片进行随机测量。 两种必须区分的摩擦制动器工作状态 制动块未接触制动盘?间隙(空间间隙)必须考虑在内(,0) x,AG 制动块接触到制动盘?无间隙(,0) x,AG 对任一状态，质量、转化摩擦力、刚度及阻尼必须单独计算。mFCdBFBBB 根据间隙值，模型在两种状态之间变换。 xAG 图13 复杂制动器模型的图形用户界面 一个用以测量中间轴承系统参数的轴承测试台可以在不同的轴向力和转速下测量摩擦力矩。通过一个很简单的图形用户界面，就可以实现人工信号激励和测量的仿真。界面可以容许改变仿真参数和集成方法。外部和内部模型信号可以选择显示。图13描绘了图形用户界面的窗口桌面。 图14 简化制动器模型的模块图 简化制动器模型——作为开发制动力计算方法的基础，建立了如图14的简化制动器模型。 ,为了简化制动器模型，我们将不同的物理参数结合起来。考虑了所有转tot d换的加速质量和转动惯量。参数包括了各个制动器元件的粘滞摩擦力矩。参tot ,v数考虑了所有的附加载荷，齿数比综合考虑了串接的行星齿轮齿数比和行tottot 星滚动轮的齿数比。 , ,,,,T,T,T,T totmF。VF。Cuse T,d,,,sign(,),(T，,F),vF , (2) mtotmmF0totcltotcl Fx制动力建模为一个依赖于主轴行程的非线形方程的特征曲线 clAG solicited opinions and suggestions Article 265, including: four problems to 171. Deepening special regulation, State line State modified, side check side modified, total solution highlight problem 19 a; to rectification spirit carried out party political life, in-depth carried out heart talk, serious carried out criticism and self-critical; put built chapter State business throughout activities always, full cleanup and established perfect a involved "four wind" aspects of system provides, new 12 items, amendment perfect 15 items, abolition 3 items. Through educational practices, "four winds" problem significantly curb, party members and cadres ' apparent change of consciousness and ability of serving the masses increased significantly. (C) to promote the sustained and healthy development of economy and society. Adhere to the "party-led township, prospering Township, eco-village, projects promoting Township and industrial Township, industry-rich Township, harmony Township, stabilization control" development strategy, take economic construction as the Center, strengthen leadership over the economic work in earnest, closely around the target determined earlier this year to deal with and try to resolve the various adverse factors, pay close attention to the work. Efforts to promoting the construction of major projects. To transportation, water conservancy, urban infrastructure construction, focusing on implementation of a number of industrial structure adjustment and optimization and upgrading of key projects for leading roles; Completed has XX village pass village Highway, and township location lights bright of, and XX meters "beautiful village", and township public rental and Xiang hospitals public rental, and 270 sets rural housing room 2 (3) F,,,,，x，,clBBBsp 信号分析: 以下部分的目的是在制动器可实现的信号根据其对制动力计算的可行性进行计算。 电机转子位置——由于电机是电子整流的，转子位置信号在制动器上就可以实现。如果整个机构的刚度已知，就可以由转子位置计算制动力。 要通过测量电机转子位置的可行性来计算制动力，就应测出每一个制动元件的刚度及其变化，为了对第三代产品进行刚度分析，将制动器的以下结构元件进行单独处理: 齿轮单元 (行星齿轮、行星滚轮及中心轴承) , 制动片 , 制动盘 , 制动块 , 系统总刚度根据串接元件的刚度由以下公式算出: 1 (4) C,制动器1112，，，CCCC制动片制动块齿轮制动盘 齿轮单元的刚度在设计过程中用CAD程序算出。刚度曲线在微小作用力下是渐变的，外力较大时呈线形特征，它约占总刚度的5,。 Continental Teves公司采用一台专用的测试台测试制动片的刚度。球墨铸铁制动片在完全装配好的机电制动器下受力发生的应变并不与外力呈线性关系。就像制动片的刚度曲线一样，是渐变的。它约占制动器总刚度的72,。 制动盘刚度可通过测量盘厚和制动盘有效工作区域及应用灰铸铁的弹性模量算出，其约占制动器总刚度的2,。 我们采用了对串接放松的新制动块进行随机测量的通用机械测量制动块刚度，如图15所示。制动块在冷却条件下11mm厚时约占系统总刚度的21,。 图15 不同厚度与温度下的制动块刚度 图16 描绘了制动器各元件刚度在总刚度中所占的比例。 图16 Continental Teves公司第三代制动器中各元件占系统总刚度的百分比。 齿轮单元和制动片的最高温度只有200?。因此，它们受温度影响对制动器总刚度的变化是可以获略的。 尽管制动盘在温度上升到800?时，刚度约变化大约20,，但由于其只占总刚度的2,，所以，其对系统总刚度的变化还是可以获略的。 制动块由于磨损和温变产生的影响可达原值的200,，而且由于其占系统总刚度的21,，所以其影响是非常大的。 为了证明其影响，图17给出了四种不同的刚度特征曲线。制动块的厚度和温度不仅影响刚度，而且影响电机转子转角和制动力响应的滞后。 solicited opinions and suggestions Article 265, including: four problems to 171. Deepening special regulation, State line State modified, side check side modified, total solution highlight problem 19 a; to rectification spirit carried out party political life, in-depth carried out heart talk, serious carried out criticism and self-critical; put built chapter State business throughout activities always, full cleanup and established perfect a involved "four wind" aspects of system provides, new 12 items, amendment perfect 15 items, abolition 3 items. Through educational practices, "four winds" problem significantly curb, party members and cadres ' apparent change of consciousness and ability of serving the masses increased significantly. (C) to promote the sustained and healthy development of economy and society. Adhere to the "party-led township, prospering Township, eco-village, projects promoting Township and industrial Township, industry-rich Township, harmony Township, stabilization control" development strategy, take economic construction as the Center, strengthen leadership over the economic work in earnest, closely around the target determined earlier this year to deal with and try to resolve the various adverse factors, pay close attention to the work. Efforts to promoting the construction of major projects. To transportation, water conservancy, urban infrastructure construction, focusing on implementation of a number of industrial structure adjustment and optimization and upgrading of key projects for leading roles; Completed has XX village pass village Highway, and township location lights bright of, and XX meters "beautiful village", and township public rental and Xiang hospitals public rental, and 270 sets rural housing room 图17 不同制动块厚度和制动盘温度下整个制动机构的刚度 对电机转子位置的分析表明只要能找到一种调整刚度曲线的方法，就可实现根据刚度特性曲线计算电机转子位置。 电机电流——电机电流是对制动力修正的可行的第二个机电制动器信号。 图18 不同制动状态下制动力与电机电流的关系 图18描绘了在控制制动钳力的条件下制动器在不同状况下运行时电机电流和制动力的关系制动夹紧曲线和松开曲线之间的区域就表明了机电制动器的Fcl 效率。间隙越大，则效率越差。图18所示，电机电流制动曲线中，当制动力很小时，低谷后有一峰值，这是由于制动机构刚刚启动时，需要一个相对较大的转矩加速其惯性质量以消除制动器的运动间隙。 然而，图18主要体现的时在不同制动条件下制动曲线的形状。由图3我们已经知道机电制动器转换参数中主要影响因素时温度和磨损，所以，为了深入研究，就不断改变二者之间的影响。在温度变化上，可以通过将制动力持续施加5分钟，以使其制动温度达到400?，这样，制动热就扩散到了整个制动机构。温度升高可以提高润滑脂的粘性，进而会降低中心轴承和行星滚轮的摩擦，摩擦降低也就是效率的升高，图18也体现了这一点。 为了模拟磨损的影响，采用人为磨损过的主轴，其结果时大大增加了主轴坏道与滚子间的摩擦。以这种形式造成的效率降低会致使PRG在各制动力下产生自锁，见图18。 对于巨大的滞后和变化的齿轮效率，仅仅使用电机效率来对制动力进行修正是不大可行的，仅由一个特定的电机电流值，在效率和制动条件未知的情况下，是不可能算出制动力的精确值的。 制动力计算: 为了了解开发制动力算法中的问题，有必要进一步分析简化制动器模型的方程(2)，将方程(1)代入等式(2)，然后将可测量的量全部移到左边，可以得出: , ,I,,,,T，T，T mtotmFcFvuse.. ,T，T F.cuse sign(,)(T，,F)，,F , mF0totcltotcl , sign(,)(T，,c,)，,c, , (5) F0tottotmtottotmm 即使在制动过程中，粘滞摩擦相对与外加扭矩和库仑摩擦转距是可以忽略 ,c,的，仍然还有两个未知参数和，且二者都和电机转子转角相联系而作tottotm为输入变量。从技术角度来看，可用转矩和摩擦转矩一起体现了机电转换器的载入。没有内部信号可以将二者在参数上分开。因此，有参考文献(12)的算式(2)，未知参数不能由普通的参数识别方法算出。 然而，可以利用机电制动器的一个特性在摩擦损失未知的情况下算出当前的制动力。制动器有两种工作状态:夹紧和放松。再看一下算式(5)，摩擦损失的solicited opinions and suggestions Article 265, including: four problems to 171. Deepening special regulation, State line State modified, side check side modified, total solution highlight problem 19 a; to rectification spirit carried out party political life, in-depth carried out heart talk, serious carried out criticism and self-critical; put built chapter State business throughout activities always, full cleanup and established perfect a involved "four wind" aspects of system provides, new 12 items, amendment perfect 15 items, abolition 3 items. Through educational practices, "four winds" problem significantly curb, party members and cadres ' apparent change of consciousness and ability of serving the masses increased significantly. (C) to promote the sustained and healthy development of economy and society. Adhere to the "party-led township, prospering Township, eco-village, projects promoting Township and industrial Township, industry-rich Township, harmony Township, stabilization control" development strategy, take economic construction as the Center, strengthen leadership over the economic work in earnest, closely around the target determined earlier this year to deal with and try to resolve the various adverse factors, pay close attention to the work. Efforts to promoting the construction of major projects. To transportation, water conservancy, urban infrastructure construction, focusing on implementation of a number of industrial structure adjustment and optimization and upgrading of key projects for leading roles; Completed has XX village pass village Highway, and township location lights bright of, and XX meters "beautiful village", and township public rental and Xiang hospitals public rental, and 270 sets rural housing room 绝对值在制动力相同时沿两个方向作用是相等的。用相同的方法，T，,FFF0totclcl 假使某一电机转子转角在很短的时间内传给两个相反的转动方向，致使尚,ctmtot未发生改变，输出转角相同，摩擦损失的绝对值在两个方向都是T，,c,F0tottotm ,相等的，由可用的电机转矩(根据惯性损失修正过)，由方程(2)导出了以Tm 下制动方程: , T,(T，,F)，,Fm,clF0totcltotcl , (6) (T，,c,)，,c,F0tottotmtottotm 释放制动时: ,T,,(T，,F)，,Fm,rlF0totcltotcl , (7) ,(T，,c,)，,c,F0tottotmtottotm 将两式相加，就可以得出某一电机转子转角下的制动力: ,,T，Tmclmrl,, (8) F,cl2,tot ,,TT图19描绘了使用电机制动转矩和释放转矩。制动器效率小于100,时制,,mrlmcl 动曲线就到了理想状况下(效率为100,)的上方。而释放时曲线就位于其下方。两种状态下，到理想曲线的距离总是相等。 图19 循环计算下机电制动器的效率图 通过在一个振幅很小的由驾驶员或电子安全系统发出的控制信号上附加一个高频的位置输入信号，制动器机构可以很快在两个方向达到指定的转角。激励信号应由一个处理标准来控制，以便当输入信号梯度很小时可以加上。这样，电机转矩转角曲线就覆盖了很小的区域，如图19效率曲线所示。 为了提高制动力计算值的精度，对沿这一区域的所有点进行测量。因此，就使用了很多种方法，图20显示了复杂制动器模型的7种方法的计算结果。方法2计算了线的纵坐标，它在垂直方向上将区域两等分。另一种方法就是算出这一条线(比如使用最小二乘法)，使之最佳地符合由方程(8)得出的与区域内转子转角对应的值。然后，由计算曲线与转子转角的交点就可以得出所需的制动力(方法7)。方法5采用计算区域重心纵坐标的方法。由于最后一种方法得出的仿真效果最好，而且易于在微控制器上实现实时计算，就被用于深入研究。 图20 不同计算方法下制动力的计算结果 为了证实粘滞摩擦可以忽略这一假设，图21分别描绘了考虑与忽略粘滞摩擦 T下设置不同制动力值时计算制动力的值。然而，用转动惯量对制动转矩进行m修正是必要的。特别是在制动力很小的情况下，电机转矩也很小，转动惯量对计solicited opinions and suggestions Article 265, including: four problems to 171. Deepening special regulation, State line State modified, side check side modified, total solution highlight problem 19 a; to rectification spirit carried out party political life, in-depth carried out heart talk, serious carried out criticism and self-critical; put built chapter State business throughout activities always, full cleanup and established perfect a involved "four wind" aspects of system provides, new 12 items, amendment perfect 15 items, abolition 3 items. Through educational practices, "four winds" problem significantly curb, party members and cadres ' apparent change of consciousness and ability of serving the masses increased significantly. (C) to promote the sustained and healthy development of economy and society. Adhere to the "party-led township, prospering Township, eco-village, projects promoting Township and industrial Township, industry-rich Township, harmony Township, stabilization control" development strategy, take economic construction as the Center, strengthen leadership over the economic work in earnest, closely around the target determined earlier this year to deal with and try to resolve the various adverse factors, pay close attention to the work. Efforts to promoting the construction of major projects. To transportation, water conservancy, urban infrastructure construction, focusing on implementation of a number of industrial structure adjustment and optimization and upgrading of key projects for leading roles; Completed has XX village pass village Highway, and township location lights bright of, and XX meters "beautiful village", and township public rental and Xiang hospitals public rental, and 270 sets rural housing room 算结果的误差影响很大。 图21 粘度修正和惯性修正对计算结果的影响 进一步对复杂制动系统进行模拟分析，以找到对外加激励信号的优化频率和幅值。而且模型仿真对电机电流和转子转角信号的滤波器进行了证明。 图22 实际制动器模型的制动力计算结果 将MATLAB的制动力算法转化为微控制器程序平台的C语言格式。图22给出了实际制动器在16位微控制器下的计算机结果。 由于微控制器对小电机电流值AD转换时量化误差的不断增加及采用相对误差进行描述的原因，在制动力小的情况下有很大的相对误差。 图23 制动力修正方法的模块图 然而，计算出的制动力不可以直接用于制动器的控制，因为其以一种非常小 ,的频率发生无的更新。因此，第二种方法可以通过使用计算的制动力数值Fcl调整简化制动器模型(如刚度特性曲线)。调整时可以忽略一些因素，采用最小二乘法，参阅参考文献,12,。为了控制制动器，要对调整后的制动器模型的制动力输出进行处理。 图23以图块的形式描绘了总制动力修正的算法。为了实现这一过程，刚度特性曲线选作位可调整模块。由图17，我们可以发现不同温度和不同制动块厚度下，刚度特性曲线很相似。仅用一个比例因子将不同的制动力和转子转角关系分开。 为了调整刚度特性曲线，因此只需以图表形式存入一条基本特性曲线，然后 ,，再不断减少制动力计算值F与模型输出的误差采用不同的比例因子F,,cl,estclest 就行了，见图24。在实际应用中，将一常规的磨损过的制动块(约厚8mm)的刚度曲线作为一个毫无迟滞的中性线存入微控制器的存储单元中。对这些曲线上的点之间的值，用插值法求取。为了找到模型误差最小的曲线点，可以用Simplex算法优化处理。 图25给出了对曲线点优化过的刚度特性曲线。 图24 同一化方法的模块图 图25 以曲线点形式存入的刚度特性曲线 间隙处理: 有两个原因使间隙处理成为电制动器低成本控制中的一大问题。与液压释放后间隙可以自动调整的液压制动器相比，机电制动器必须要主动调整间隙。第二个要找到其接触点的原因是因为这一点就是刚度特性曲线的零值点，见图25。接触点测量的准确程度就直接影响到制动力计算的精度。 在这种动因下，我们研究了一种只根据电机转子位置和电机电流来检测制动 ,dTm,,块与制动盘接触点的方法。通过计算刚度商数:，使检测与制动力信号d,m 设置值相独立。这一值在超过某一边界值时可以被检测到。 用这种启动方法在系统启动后可以对制动器进行初始化。它也可以对正常制动下每一次制动的信号进行处理，以适应刚度曲线的零值。 为了证实这种新方法使用的可重复性，对其进行了192次运行检测。图26描绘了绝对检测误差的分布情况。 solicited opinions and suggestions Article 265, including: four problems to 171. Deepening special regulation, State line State modified, side check side modified, total solution highlight problem 19 a; to rectification spirit carried out party political life, in-depth carried out heart talk, serious carried out criticism and self-critical; put built chapter State business throughout activities always, full cleanup and established perfect a involved "four wind" aspects of system provides, new 12 items, amendment perfect 15 items, abolition 3 items. Through educational practices, "four winds" problem significantly curb, party members and cadres ' apparent change of consciousness and ability of serving the masses increased significantly. (C) to promote the sustained and healthy development of economy and society. Adhere to the "party-led township, prospering Township, eco-village, projects promoting Township and industrial Township, industry-rich Township, harmony Township, stabilization control" development strategy, take economic construction as the Center, strengthen leadership over the economic work in earnest, closely around the target determined earlier this year to deal with and try to resolve the various adverse factors, pay close attention to the work. Efforts to promoting the construction of major projects. To transportation, water conservancy, urban infrastructure construction, focusing on implementation of a number of industrial structure adjustment and optimization and upgrading of key projects for leading roles; Completed has XX village pass village Highway, and township location lights bright of, and XX meters "beautiful village", and township public rental and Xiang hospitals public rental, and 270 sets rural housing room 图26 接触点绝对测量误差的分布 进而，也对主轴/制动块在不同起始条件下接触点的测量方法进行了测试。图27表明在改进方法下起始点对测量精度没有影响。 图27 不同起始点下间隙调整结果 实验结果: 为了证明新的制动力算法包括间隙处理方法的潜力，我们对两个制动测试回路进行了分析。首先，用一套实际的制动力设备对BMW318i进行驾驶试验，置以信号值，并将其作为车轮模块的输入。修正的制动力由制动力控制器处理以作为反馈。为了证明计算的准确性，图28对修正的制动力信号和集成传感器的参考信号作了对比。二者非常吻合。 图28 BMW318i进行制动力设值的计算结果 第二个试验是在修车厂进行制动块变化。磨损坏的制动块(厚度2mm)换成新制动块(11，8mm)，图28所示，对于就制动块，制动循环过程呈三角状运行。由于严重磨损过的制动块刚度曲线比一般磨损的制动块刚度曲线更陡，所以比例因子就更大。更换制动块后，算法就复位了，在下一个制动循环中，系统很快, 就将比例因子调整到0.7。这一过程必须在具有初始化程序的修车厂完成。相, 应的，图29也描绘了仅由基线而不对进行调整的情况。很显然，对刚度特性曲, 线的调整对计算制动力是必不可少的。 图29 制动块改变的三个制动循环测试 图30 更换制动块后的调整 , 结论: 开发电制动系统制动力算法这一挑战性的任务必须要有一个灵活开放的环境。本文所指的开发环境包括复杂的和简化的制动测试平台。通过这些工具，就可能实现制动力控制和制动力计算算法的快速设计。 在本文中，模型和测试台首先测出在可能的制动力下电机电流和电机转子转角值。据表明，二者在没有制动力传感器下都有缺陷，因为其与制动力的关系会发生很大的变化。 所以，我们开发了一种算法，以调整电机转子转角和制动力(刚度特性曲线)的关系，一个智能的处理制动块与制动盘间隙的方法。它可以很好地反复地检测制动盘与制动块地接触点并调整间隙。 最后，两个制动测试循环显示了这种新颖的制动力算法的精度质量。 solicited opinions and suggestions Article 265, including: four problems to 171. Deepening special regulation, State line State modified, side check side modified, total solution highlight problem 19 a; to rectification spirit carried out party political life, in-depth carried out heart talk, serious carried out criticism and self-critical; put built chapter State business throughout activities always, full cleanup and established perfect a involved "four wind" aspects of system provides, new 12 items, amendment perfect 15 items, abolition 3 items. Through educational practices, "four winds" problem significantly curb, party members and cadres ' apparent change of consciousness and ability of serving the masses increased significantly. (C) to promote the sustained and healthy development of economy and society. Adhere to the "party-led township, prospering Township, eco-village, projects promoting Township and industrial Township, industry-rich Township, harmony Township, stabilization control" development strategy, take economic construction as the Center, strengthen leadership over the economic work in earnest, closely around the target determined earlier this year to deal with and try to resolve the various adverse factors, pay close attention to the work. Efforts to promoting the construction of major projects. To transportation, water conservancy, urban infrastructure construction, focusing on implementation of a number of industrial structure adjustment and optimization and upgrading of key projects for leading roles; Completed has XX village pass village Highway, and township location lights bright of, and XX meters "beautiful village", and township public rental and Xiang hospitals public rental, and 270 sets rural housing room