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1、毕业设计（论文）外文翻译 题 目 关于摩擦转矩补偿在主动杆 控制中的应用专 业 电子信息工程 班 级 三 学 生 指导教师 重庆交通大学 2010 年译文：关于摩擦转矩补偿在主动杆控制中的应用摘要： 随着具有可变力感应特征的主动的不断发展，合并位置和压力控制策略能通过由机械化采用2-轴内置式压力传感器和lvdt完成了。由操作员来感应的测量杆力量的，2-轴压力传感器，是由应变计和适当的仪器放大器组合而来。另外，再用数学模型的主动杆动力学推导，和多次实验结果比较，最终于获得了成功。但是摩擦转矩杆，由于几个零件的机械联络导致依赖于震级的激励信号和精确的闭环控制的实验性频率反应极为困难。因此，又设计了
2、实时估计主动杆摩擦转距的摩擦观察器，并被应用于闭环控制。它的好处在于能通过数值模拟仿真和进行实验核实摩擦观察器。关键字：主动杆；摩擦观察器；滞后; 2-轴压力传感器; 变力感应特征1、引言杆是一种指挥新一代装置，用于飞机，远程机器人，电脑游戏机器。传统杆只提供了弹力反反作用力在响应用户的用意。然而，在更多实际情况下，人们越来越需要有主动的控制杆，它能提供压力反馈给操作者。这意味着该压力，能使操作者满足规定的，多种多样，实时的具体的应用。主动杆的应用有，军事演习的飞行员用来操作现代飞机和机械装置的控制。主动手柄在数字控制系统中具有担当重要的角色，能提高飞行员的飞行能力使其能顺利的完成其飞行任务。
3、压力感应特性可随战斗局势改变强弱。另外，它还被应用于机械战斗控制系统中战斗行动模拟器的控制装载者航空器上。 这是因为得益于气囊铰链的瞬间变化的发展，主动杆已能够模仿飞行员紧握是的反作用力。主动杆的概念将被扩展作为输入装置，即一台优质游戏机的力量感觉控制杆。这样， 输入程序就可以通过力量感觉控制杆影响比赛的状态和输入的结果，即在比赛的状态转折点，通过力量感觉控制杆能力再转移到用户。本文中所描述的主动杆的发展重点解决以下三个技术性问题。其中一项是，主动杆里能通过程序随意改变位移特性。要想实现这种功能，首先，必须得采用合并地位和武力控制战略。另外，还得考虑怎样获得杆上的柄力，只是2轴内置式力传感器的
4、发展已解决了这一问题，即在杆内装置两套半桥式应变计来感应这种力量。最后的问题是关于扭矩的摩擦引起的主动杆性能退化。因为几个零部件的机械接触，即主要是装置于杆内的齿轮箱及机械被动弹簧的减少导致主动杆内的摩擦扭矩使杆力位移特性不准确。但是，机械系统内的摩擦又是一种必然的现象，是无法控制的。在控制工程中一种最常见的对付摩擦的办法就是采用估算来估计摩擦和抵消摩擦效应。最近又报道了几种确定摩擦的方法。适应控制技术也被用来确定摩擦的其它未知影响，例如：静态和动态现象中的库仑，并利用这一信息提高闭环控制的效率。Rayet al.提出了一个扩展的KalmanBucy flter来作为摩擦估算模型 。Fried
5、land等人则在李雅普诺夫样方法（本文中所采用的）的基础上设计了估算主动杆摩擦转矩的摩擦观察器。本文介绍了机械结构和动力学模型的发达主动杆，变力感觉特征的闭环结构同时也被提上议程。根据实验结果表明，主动杆内的摩擦扭矩是实现精确的力感觉特性的其中一个主要障碍。为了消除这种摩擦的影响，采用了Friedland等人的建议，在闭环运行加入了一个观测器。这样，使用摩擦转矩观测的闭环运行设计就能通过数值模拟和实验研究来验证。2 主动杆的设计2.1 主动杆的机械结构主动杆的机械结构模型如图一所示。圆柱组成的在右边的是一个无刷直流（无刷直流）马达驱动辊轴的杆。这个马达连接到辊轴减速箱。齿轮箱的旋转轴和俯仰轴是
6、通过支架相连接的。外部的齿轮箱的转轴是固定到杆的另外的结构上，从图1可以看出，此杆是与齿轮箱的俯仰轴的表面相互连接的。由于这样的机械结构，整个俯仰轴装置与轧辊轴一同转动，而只有杆包括外围的付在齿轮箱上的俯仰轴旋转时，为总俯仰轴驱动指挥。图1还显示内建被动式的弹簧和lvdts给抚养轴及轧辊轴。图12.2.2轴力传感器的设计为了能有效的感觉到压力，两个轴上的传感器降到所需的最低限度。在压力杆感应中旋转轴测量和压力感应定量过程中有LVDT，图2是2轴传感器的示意结构图。在图2的左侧示意咯杆轴紧紧连接在碟形压力感应器的边缘。碟形边缘有四个独立的叶子和滚动轴。其中四叶子是独立向上翘起，以尽量减少耦合效应
7、之间的间距和轧辊力传感。当操作者推或拉动操纵杆时，叶子的压缩力和扩展力随位于斜对面叶子的压力的改变而改变。这些压力可以通过应变计和适当的仪器放大器来获取。安装应变计的最佳地点由FEM通过分析来决定。3 .主动杆的动态模型3.1 .主动杆的动态建模图3表示了主动杆的动态闭环模型系统。通过压力信号和位移传感器，杆在某一瞬间的移动总是确定的.图3中的压力感应块在预先编程感应特征的基础上发送转动命令给杆。图3的闭环结构是基于位置的控制系统。杆的压力感应特征和类型可以通过调用简单的程序重调模块而改变。杆的开环动态运动特性满足下列方程。图2代表每个轴旋转的角度（ RAD数据通信公司） ，FST代表操作者产
8、生的杆力，TF代表摩擦力矩（ nm ），Vm代表永磁无刷直流电动机的驱动电压（ V ） 。然后，等式1中的其他变量在表一中都有总结。方程1的第二个等式则为永磁无刷直流电动机在当前使用下的动态模式，它具有以下特点为了证实方程1的开环动态模型，对实验频率反应进行了验证。图3图4显示了这些结果。虚线是磁无刷直流电动机驱动电压的旋转角度的分析后的开环频率响应。图中的实线是通过改变永磁无刷直流电动机的励磁信号的规模得到的实验频率响应。这些线都必须得对1.2 ，0.8 ，0.6和0.4峰峰值电压激励有很大反应。频率响应形状的多变性与输入幅度的变化是一个非线性系统自然属性。主动杆所固有的摩擦转矩是造成分析和
9、实验频率响应偏差的主要原因。其次才是在图4的低频区可以看到的杆动力的其他摩擦影响。3.2 闭环设计和试验 图5显示的是一个基于比例控制器的主动杆的仿真模型。ADC #1的输出信号是俯仰轴压力传感器的感应压力。再通过调整器的偏移和适配器的增益处理，为了抑制信号噪音，信号还通过截止频率为10 Hz的二阶低通滤波器（ LPF ）。俯仰轴的转动命令是操作者通过特有的压力感应块的外力来发起的。闭环的输出是 ADC 2的输出信号。俯仰轴的误差信号的增加是由于比例增益和输出向无刷直流电动机放大器两部分所致。图5 的下部分是轧辊轴控制，具有与俯仰轴相同的环路结构。数字控制器是dSPACE的ds1102控制 。
10、根据仿真模型图5编写机器代码并下载到ds1102的TMS320C31DSP上并实时性执行。图4图5闭环时域响应如图7所示。压力杆的前向倾斜，后向倾斜，左转，右转都得到了运用，第一副图和第二副图的数据表明了倾斜杆和转动杆通过传感器获得的压力。第三的虚线和第四的图象是倾斜杆与转轴的实时命令，可以有图5的压力感应块计算得出，实线是倾斜和转轴的实时输出。倾斜杆与转动轴之间的交叉耦合效应的变化和传感器之间的间距如图6的第一图像和第二图像表示。 瞬态误差和稳态误差有第三和第四图像表示。每个机械杆的实时输出总是滞后的，导致咯，这导致杆离相对位移有滞后的现象，表示在图11的左下脚。大量比例增益的利用降低咯稳态
11、误差，如图6所示。不过这个状态不是最好的状态，相反，得留心死循环。综上所述，摩擦转矩的内嵌杆是导致许多问题的根源。为了实验测定机械机构杆之间的静摩擦转矩。在开环运行条件下给BLDC电动机放大器施加一0.2hz正弦波、峰值1.4伏。图7显示了电机驱动信号的电压，产生直流电流的电流放大器的电，以及俯仰轴所转过的角度。嘈杂的信号和矩形形状的信号分别代表激励电流和旋转移位。激励电流驱动俯仰轴旋转，斜操纵杆的角位移的不对称性表征了静态摩擦力向量值的依赖特性。静态摩擦力的值可以利用表1中所列出的转拒常数和弹性常数估计计算得出，转拒常数和弹性常数分别是6.842nm的前面（在图7逆方向）和2.064nm尾部
12、（在图7正方向），在斜杆上运动。4 、摩擦效应补偿基于以上分析，结果表明，主动杆内本生就存在着相当多的摩擦。因此，如果没有摩擦效应补偿，杆是很难实现高精确度的运作的。Friedl 10等人提出的摩擦监测器被用来实时估算杆的摩擦。主动杆的摩擦转矩的定义是以下面方程(3)为基础的，这是类似库仑摩擦代表性的参数，a是由下列方程更新演变而来的。图6图7图8图9图10图11上述观察器的动力的运行必须始终是稳定的，以选择好指数U和获得正值的K。这些参数决定了速度a必须与真实值相吻合。用来核实上述摩擦观察器运行的数值仿真器已被制造出来了。在这次模仿中，假设是模拟图8的摩擦扭矩，图9即是这次模拟的模仿显示。
13、图9的上部是主力杆闭合回路动力学的摩擦模型图8。这次模仿采用的是0.05的比例增长。 低部显示的是在方程(4)中描述的摩擦观察器。 在大量的模仿以后， u的价值和k最终被确定为3和50，以保证摩擦观察器能有适当的动力。图10是对所有模仿结果的总结。 这个图第一部分是摩擦扭矩的时间记录，它在模拟过程中随着图8.的特征的变化而变化。第二种部分是用观察器估计的摩擦扭矩。它与摩擦扭矩的真实值并不完全一致,但是与其平均值相同。 第三和第四部分是第一和第二部分的其他补充介绍。 实验结果表明,Friedland等人提议的摩擦扭矩观察器并不能复制图8的静态摩擦和Stribeck作用，只是能够相当好地估计库仑摩
14、擦扭矩。图11显示一些实验性数据。在这个实验中,主动杆的闭合回路控制的结构里有一个与图9结构一样的摩擦观察器。 在图11上面部分的虚线和实线分别表示了旋转音调的命令和它的相应反应。 摩擦扭矩报偿的应用大大减少了相当数量的瞬变和稳态误差，这与图6中的第三部分比较起来显得尤为醒目。左下方展示了俯仰轴的实验性力感特征。可以看出，当主动杆的运动改变方向时，它会表现出滞后行为，并且摩擦扭矩总是变得更大。图11的最后部分是估计后主动杆的摩擦转距。经过一个开环实验性测试，它的结构得到了重建，摩擦扭矩的数量及其定向附属品与图8相似。5 、结论 主动杆感应力完全能反馈给操作者，是主动杆在研究方面的一大进展。主动
15、杆数学模型通过起初的思想到实验结果的反复比较达到了预期的目的。结果表明，摩擦扭矩应用杆的实现高精确度的操作，归功于杆的多部分零件的在机械连接中产生的大摩擦力。观测者认为操纵杆的摩擦力效果是被补偿的。摩擦观察员的功能通过数值模拟和实验研究得到验证。因为该观察员是自动的，精确回收的在静摩擦力和stribeck效果的恢复过程中有一定的精度局限性。然而，实验结果表明，这种摩擦观察员抄录实时摩擦扭矩平均水平。它验证了该应用的摩擦观察员在主动杆的闭环控制绩效相对与压力特性杆的有了较大的改善。原文Active stick control using frictional torque compensatio
16、nYoonsu Nam , Sung Kyung HongAbstractAn active stick which has variable force-feel characteristics is developed. A combined position and force control strategy is mechanized by using a 2-axis built-in force sensor and LVDT. The 2-axis force sensor, which measures the stick force felt by the operator
17、, is developed by using strain gages and appropriate instrumental amplifiers. A mathematical model of the active stick dynamics is derived, and compared with the experimental results. The frictional torque of the stick due to the mechanical contact of several parts causes the experimental frequency
18、responses to be dependent on the magnitude of the excitation signal and the precision closed loop control to be difficult. A friction observer which estimates the frictional torque of the active stick in real time is designed, and applied to the closed loop control. The benefit of using the friction
19、 observer is verified through numerical simulation and experiments.2004 Elsevier B.V. All rights reserved.Keywords: Active stick; Friction observer; Hysteresis; 2-Axis force sensor; Variable force-feel characteristics1. IntroductionA stick is a kind of command-generation device for an aircraft, tele
20、-robot, and game machine. The conventional stick provides only a spring-reaction force in response to the user intention. However, in more realistic situations, there is a growing need for an active stick, which supplies force feedback to the operator. This means that the force that the operator fee
21、ls can be varied in real time to meet the requirements of the specific applications. The application of an active stick can be found in a pilot inceptor of a modern aircraft and a control loading mechanism for fight motion simulation 15. An active stick in a digital fight control system plays an imp
22、ortant role in maximizing the pilots ability to perform his mission. The force-feel characteristic can be changed to be soft or strong, depending on the fight regime. Another application of an active stick is for a control loader in a fight motion simulator for aircrafts using a mechanical fight con
23、trol system. The active stick can simulate the reaction force from a pilot inceptors grip, which is developed due to the hinge moment variation in the hight envelope. The concept of an active stick is to be expanded as an input device, i.e. force-feel joystick, for a high-quality game machine. The i
24、nput through the force-feel joystick influences the state of a game, and the effect of this input, i.e. the state transition in a game, is again transferred to the user through the force-feel joystick capability.The development of the active stick which is to be described in this paper is focused on
25、 solving the following three technical problems. One of these is that the stick force versus displacement characteristic can be easily changed by programming. A combined position and force control strategy is necessary to fulfill this capability. A second concerns how to pick up the grip force on a
26、stick.A2-axis built-in force sensor is developed to resolve this problem. Two sets of half bridge strain gages are installed inside the stick to sense these forces. The final problem concerns the performance degradation of the active stick due to the frictional torque. This comes from the mechanical
27、 contact of several parts, i.e. mainly from the reduction gear box and mechanical passive spring installed inside the stick. The frictional torque in the active stick makesthe stick force versus displacement characteristic inaccurate.Friction is an inevitable phenomenon in the mechanical system and
28、can not be controlled. A common method in control engineering to deal with friction is that of estimating friction and canceling out the friction effect by using that estimated. Several methods for identifying friction have been reported recently. Adaptive control techniques are applied to identify
29、the unknown effects in friction, such as the Coulomb, static, and Stribeck phenomena, and to enhance the performance of the closed loop control by using this information 68. Rayet al. proposed an extended KalmanBucy flter for a friction estimating model 9. Friedland et al. designed a friction observ
30、er based on a Liapunov-like method 1012, which is adopted in this paper for the frictional torque estimation of the active stick.This paper describes the mechanical structure and dynamic model of the developed active stick. A closed loop structure for the variable force-feel characteristic is also p
31、roposed. Based on the experimental results, it turns out that the frictional torque inside the stick is one of the major barriers to achieving the precision force-feel characteristic. To cancel out this friction effect from the closed loop operation, an observer proposed by Friedland et al. is appli
32、ed. The performance of the closed loop design using a frictional-torque observer is veri?ed through numerical simulation and experiment.2. Design of an active stick2.1. Mechanical structure of the active stickFig. 1 shows the CAD modeling for the mechanical structure of the developed stick. The cyli
33、ndrical component on the right side is a brushless DC (BLDC) motor which drives the roll axis of the stick. This motor is connected to the roll-axis reduction gear box. The rotational axis of this gear box is combined with that of the pitch axis gear box through the bracket. The exterior of the roll
34、 axis gear box is fixed to the external frame of the stick. As can be seen from Fig. 1, the stick rod is connected to the exterior of the pitch-axis gear box. Because of this mechanical structure, the whole pitch-axis assembly of the stick rotates together with the roll-axis rotation, and only the s
35、tick rod including the exterior of the pitch-axis gear box rotates for the pitch-axis driving command. Fig. 1 also shows the built-in passive springs and LVDTs for the pitch and roll axes.2.2. Design of a 2-axis force sensorIn order to have force-feel capability, two sensors per axis are minimally r
36、equired. These are the LVDT for measuring the axis rotation and the force sensor for quantifying the stick force felt by the operator. The schematic structure of a 2-axis force sensor is depicted in Fig. 2. The stick rod is tightly connected with the dish-type force-sensing flange, which is shown on
37、 the left side of Fig. 2. The flange has four independent wings to pick up the pitch and roll-axis force, respectively. The four wings are isolated from each other to minimize the coupling effect between the pitch and roll force sensing. As the operator pushes or pulls the stick, the compression for
38、ce for one wing and the extension force for the other wing located diagonally opposite are developed. These forces can be picked up by using strain gages and appropriate instrumental amplifiers. The best locations for installing these strain gages are determined based on FEM analysis.3. Dynamic mode
39、l of an active stick3.1. Modeling of the active stick dynamicsFig. 3 represents the closed loop structure for the active stick. By using information from the force and displacement sensors, the stick force at a certain instant of stick movement is always identified. The force-feel characteristic blo
40、ck in Fig. 3 generates the rotational command for each axis, based on the pre-programmed feel characteristics. The closed loop structure of Fig. 3 is basically a position control system. The force-feel characteristics of the stick can be changed to any type by simply reprogramming this block. The op
41、en loop dynamics of the stick movement is governed by the following equations.Where is rotational angle for each axis (rad); FST is stick force generated by operator (N); Tf is friction torque (Nm); Vm is BLDC motor driving voltage (V). The other variables used in Eq. (1) are summarized in Table 1.
42、The second equation of Eq. (1) represents the dynamics of the current ampli?er for the BLDC motor, which has the following characteristicIn order to verify the open loop dynamic model of Eq. (1), the experimental frequency responses are investigated.Fig. 4 shows these results. The dotted line in Fig
43、. 4 is the analytical open loop frequency response of the pitch rotational angle for the BLDC motor driving voltage. The solid lines in this figure are the experimental frequency responses, which are obtained by varying the magnitude of the BLDC motor excitation signal. These lines in the order of h
44、aving large magnitude correspond to 1.2, 0.8, 0.6, and 0.4 peak-to-peak volt excitation. The variation of the frequency response shape with the input magnitude change is the natural property of a non-linear system. The frictional torque inherent in the stick is the main cause of the deviation of the
45、 analytical and experimental frequency response. The other frictional effect on the stick dynamics is the phase delay, which can be seen in the low frequency region of the phase plot in Fig. 4.3.2. Closed loop design and experimentsThe SIMULINK model of the active stick controller is shown in Fig. 5
46、, which is basically a proportional controller. The signal coming from ADC #1 is the output from the pitch axis force sensor. After offset adjustment and suitable gain processing, this signal is applied to the second-order low pass filter (LPF) having a cut-off frequency of 10Hz, in order to suppres
47、s the signal noise. A pitch-axis rotational command calculated based on the applied force by the operator is generated through the force-feel characteristic block. The loop is closed with the pitch LVDT output signal of ADC #2. The developed pitch-axis error signal is multiplied by the proportional
48、gain and output to the BLDC motor amplifier. The lower part of Fig. 5 is for the roll-axis control, which has the same loop structure as that of the pitch axis. The digital control is effected by the DS1102 board of dSPACE .The SIMULINK model of Fig. 5 is changed to the machine codes for a TMS320C31 DSP on a DS1102, downloaded and executed in real time.The closed loop time domain responses are shown in Fig. 7. These are obtained by applying the stick force in a sequence of t