上海电力学院自动化专业英语句子

1、A: 1:A feedback system is often better able to cope with unexpected disturbances and uncertainties about the system s dynamic behavior. 一个反馈系统经常能更好的应付不期望的 扰动作用以及系统动态性能的不确定性,/However ,it need not be true that closed-loop control is always superior to open-loop control .然而, 闭环控制并不一定总是优 于开环控制,/When the

2、 measured output has errors which are sufficiently large ,and when unexpected disturbances are relatively unimportant ,closed-loop control can have a performance which is inferior to open-loop control.当输出的测量误差足够大或不 期望的扰动无关紧要时,闭环控制的性能就会比开环控制的 差2:An analog-to-digital converter(ADC is used to convert a

3、 continuously variable signal to a corresponding digital form which can take any one of a fixed number of possible binary values. 一模拟 -数字转换器(ADC 用来将连续变换信号编 程相应的数字量,这数字量可是可能的二进制数值中的一固 定值。3:A new phase in robot applications has been opened with the development of “ intelligent robot ” . 一个机器人应用的新局 面随着

4、“智能机器人”的发展而已近打开。4:An example is the speed control system of a turbine-generator set in a power station ,whose main purpose is to maintain the generator speed as nearly constant as possible 。电厂涡轮发电 机组就是一个例子,它的主要目的是维持发电机的转速尽可 能的接近于恒值。5:An example of this type of sensors would be a vision sensor uses t

5、o locate and identify objects and position of the robot itself ,combined with a tactile sensor used to detect the distribution of force and pressure ,and determine torque ,weight ,center of mass and compliance of the material it handles . 这类传感器的一例是视觉传感器,用于对物体和机 器人本身的定位和辨别;并结合触觉传感器用于探测力和压 力的分布和确定力矩,质

6、量,重心,按所抓取的材料决定握 持 力 。 /The hand-eye coordination for general-purpose manipulation will be extremely powerful in the industrial world .这种用于通用的手眼配合操作在工业界将会变得极为有效 力。6:A robot , once properly programmed ,will not put a chip in the wrong place .一旦适当地编程,机器人就不会将芯片发错 地方。C: 1:Care must be taken when connecti

7、ng logic circuits to ensure that their logic levels and current ratings are compatible连接逻辑电路时,必须小心翼翼,以保证它们的逻辑电平和 电流额定值是兼容的。 /The output voltages produced by a logic circuit are normally specified in terms of the worst case values when sourcing or sinking the maximum rated currents.由 逻辑电路产生的输出电压通以拉出或

8、灌入最大额定电流时, 按最弱情况下数值说定义。2:Consider the armature-controlled D.C .motor shown schematically in Fig.25.1. 图 25.1是电枢控制的直流电机。 /Such motors are fairly common components in systems of interest to control engineers . 这种电机是控制工程师在系统 中应用的比较普遍的元件。 /The torque m(t developed by the motor and hence its angular velo

9、city w(t (or in some applications ,its angular position are controlled by varying the voltage v(t applied to the armature winding . 可以靠改变电枢 绕组上的电压 v (t 去控制电机的转矩 m (t ,从而控制角速度 w (t ( 在某些应用中为角位移 。 /The stator (field winding is connected to a constant voltage source ,so that the current and hence the m

10、agnetic flux f in the field winding are approximately constant .定子(磁场绕组接到恒压电源上, 因此其电流所产生的磁场中的磁通 f 是接近于常数的。 D: 1:Denoting the mass moment of inertia of the armature as J ,and assuming that there is an externally applied load torquemL(t and a viscous friction torque Cw(t opposing the motion ,we may wr

11、ite 设电枢的转动惯量为 J , 外加负载转矩 为 mL (t ,摩擦转矩为 Cw(t,两者都是阻碍运动的,于是得 E: 1:Every time the interface is used to read a transducer ,the same operations must be carried out to convert the input number into a more convenient form.接口总是用于读取传感器的值, 同时还要将输入数值转换成更容易的形式。F: 1:Fig1.4 shows volt-ampere curves for a metal fi

12、lament lamp ,V1( , and for a carbonfilament lamp V2( ,图 1.4中的曲线 V1( 和 V2( 分别表示 -金属丝灯泡和碳丝灯泡 的伏 -安特性曲线, /As is seen , the relation between the voltage and the current in each lamp is other than linear . 如图 所示每个灯泡的电流和电压之间的关系并不是线性的, /The resistance of the metal-filament lamp increases ,and that of the c

13、arbon-filament lamp decreases with increase of current.随着电 流的增加,金属丝灯泡的电阻是增加的,而碳丝灯泡的电阻 是减少的。2:Figure 21.1 shows a common application of automatic control found in many industrial plants.图 21.1显示出了在许多工业工 厂所见到的常用的自动控制应用。 3:Fig.37.1 is a general representation of an open-loop control system . 图 37.1是对开

14、环控制系统的一般性表示。 /The input or control u(t isselected based on the goals for the system and all available a priori knowledge about the system .输入变量或控制作用 u (t 是根据本系统的目标以及所有可获取的先验知识而选定的。 /The input is in no way influenced by the output of the system ,represented by y(t . 输入变量绝不会受到 y(t 所表示 的系统输出变量的影响。 /If

15、unexpected disturbances act upon an open-loop system ,or if its behavior is not completely understood ,then the output will not behave precisely as expected .如果有不期望的扰动作用在开环系统上,或者如果 其行为不能完全掌握的话,则该系统的输出就不会完全如预 期般动作。4:Finally ,the computer interprets or understands what the image represents in terms of

16、 knowledge about the scene and gives the robot a symbolic description of its environment .最后, 计算机能就场景的辨别,理解图像所表示的含义或作出解 释,并使机器人用符号对环境的描述。5:For every process there must be final actuator that regulates the supply of energy or material to the process and changes the measurement signal . 对每一过程,均必须由最终的控

17、制器来 调节过程中能量或材料的供给量,并且改变测量值。 /Most often this is in some kind of valve , but it might also be a belt or motor speed ,louver position ,and so on .最常见的是由某种阀来完成,但这也可能是一条皮带,或者是马达速度,口径位 置等等。6:For example ,many transducers have variable resistance which must be converted to a voltage by a special circuit.

18、举例 来说,许多传感器具有电阻变换,这必须由一专门电路转换 成电压。 /This process of converting the transducer output into a voltage signal which can be connected to the rest of the system is called signal conditioning. 这种将传感器输出转换成电压信 号,并与系统的其它电路相连接的过程,称为信号调整。 7:For negative feedback to exist ,either A or B must be a negative quant

19、ity to give the loop phase inversion , and the return difference is always (1+AB for negative feedback .为了 形成反馈, A 或 B 必须为负量以使得环路形成倒向,因而对 于负反馈深度恒等于(1+ab .H: 1:However ,this advantage is more than outweighed by the disadvantages of open-loop control and the inherent advantages of feedback systems . 然

20、而, 这一优点比不上开环控制的缺点 和 反 馈 系 统 的 固 有 优 点 。 /First ,in many cases the implementation of the open-loop control suggested above would require a very sophisticated (and hence expensive computing device to determine the inputs required to counteract the predicted disturbance effects .首先,在许多情况下,实现上面所提到的开环控制需

21、要一台非常完善的(因而很费钱的计 算装置,一边用它算出抵消预估扰动影响所需的输入量。 /Second , a feedback system turns out to be inherently far less sensitive to the accuracy with which a mathematical model of the system has been determined.其次,反馈系统对数学模型的 精度并不是很敏感。I: 1:If all elemental equations are for all time ,then the system isa continuo

22、us time system . 如果所有的基础方程都定义整个 时间过程,那么,该系统也是连续时间系统。 /If ,as in sampling or digital systems ,some elemental equations are defined or used only at discrete points in time ,a discrete-time system is the result . 而假如,在采样问题或数字系统中常见 这种情况,有些基础方程仅定义于,或仅能应用于离散的时 间点上, 这就导致了离散时间系统。 /Continuous-time system are

23、 described by differential equation ,discrete-time systems by difference equation.连续时间系统用微分方程描述,而离散时 间系统则用于差分方程描述。2:If all elemental equations are linear ,so is the system .如果所 有的基础方程都是线性的,那么该系统也是如些。 /If one or more elemental equations are nonlinear ,as is the case for a diode ,then the overall syst

24、em is nonlinear .如果一个或多个基 础方程是非线性的,例如在应用二极管的场合,那么整个系统也就成了非线性的的。 /When all elemental equations can be described by a set of constant parameter values ,as in the familiar RLC circuit ,the system is said to be stationary or time-invariant or constant coefficient .当所有的基础方程都能 用一组定常参数值来描述, 正如熟知的 RLC 电路的情况

25、, 就 称该系统是稳态的, 或时不变的, 或常系数的。 /If one or more parameters ,or the very form of elemental equation ,vary in a known fashion with time ,the system is said to be time-varying .如果有一个或多个参数,甚至连基础方程本身都以一种已知 方式随时间而变化,则此系统就称为时变系统。 /Finally ,if there are no external inputs and the system behavior is determined e

26、ntirely by its initial conditions ,the system is said to be homogeneous or unforced . 最后, 如果没有外部输入信号, 系统的行为完全由自已的初始条件确定,该系统就称为齐次 或 非 强 迫 系 统 。 /With forcing functions acting ,a nonhomogeneous system must be considered .有强迫函数作用 于上的,则系统必须作为非齐次的来考虑。3:In each case ,the input circuit of the amplifier can

27、 be represented by an equivalent passive impendence Zi defined as the ratio of Vi/Ii or admittance Yi ,defined as Ii/vi. 在每种情况 下, 放大器的输入回路都可以用一个等值无源阻抗 Zi (Zi 是 vi 与 Ii 的比值 or 等值导纳 Yi (Yi 是 Ii 与 Vi 比值 来表示。4:In practice ,a RTD may be used with as much as 500 feet of three-conductor cable without creat

28、ing a perceptible error .实践 中,热电阻探测器可使用至多 500英尺的三导线电缆,而不 会产生任一可察觉的误差。5: In the process plant ,it is impractical to locate the control instruments out in the place near the process .在过程工厂中, 将 控制仪器安装在室外靠近过程的地方是不现实的。6:In this case the signal conditioning section must convert the incoming signal to a fo

29、rm which can be connected directly to the next part of the interface ,the input/output section of the microcomputer itself. 这种情况下,信号调理单元必须将输入 信号变换成为另一信号,也可直接与接口的下一部分,即微 计算机本身的输入输出单元相连接。7:It is assumed in each case that the forward-path amplifier of a negative feedback system is unilateral ,so that s

30、ignals can pass from input or output ,but not in the reverse direction from output to input ,and the only feedback path is through the network B。 而有种情况下,均假定负反馈网络中的放大器是单向的。于 是信号只能从输入端到输出端,而不能反方向传递。于是唯 一的反馈路径即通过网络 B 。8:It is hoped that these will not only give the reader some familiarity with the proc

31、ess of model-building but also satisfyhim that linear differential equations are ,in fact ,reasonable models for a wide range of real systems .希望这些工作不单是 使读者熟悉模型建立的过程,而且也使大家确信,线性微分 方程是各种实际系统的合理模型。I: 9:It is usually possible to vary the set value in such a system by manual adjustment of a control knob

32、 or by means of an auxiliary automatic control system. 通过手动调节控制旋钮或 者用辅助的自动控制系统可以改变这个设定值。10:It should be understood that any division of control engineering into “ regulators ” , ” servo-mechanisms ” and “ process-control systems” is very artificial and is really due to historic rather that logical r

33、easons , A process-control systems is often a regular .我们应该了解到 :把控制工程分成调节器、伺 服机构与过程控制系统是由人为因素造成的,这是由于历史 上的原因而不是逻辑上的原因。过程控制系统通常是一个调 节器。 /However ,a complicated process-control systems may possibly contain devices which could be defined as servo-mechanisms .The following are examples of control proble

34、ms usually classified as process control。 然而一个复杂的 过程控制系统可能包含好几个被称作伺服机构的装置。 11:Its standard range is from 4 to 20mA DC for the currentsignal or from 1 to 5V DC for the voltage signal .其标准范围对 电流来说是 4-20mA DC,对电压力信号来说是 1-5V DC。 M: 1:Measurement must be made to indicate the current value of the variable

35、 controller by the loop . 必须具有测量环节,以 指示被测回路所控制的变量当前值。 /Common measurement used in industry include flow rate, pressure , level, temperature ,analytical measurement (such as pH ,ORP and conductivity ,and many others particular to special industries. 在工业中所使用的常规测量包括流量,压力,物位,温度, 分析测量参数,如 PH 值, ORP 和电导率

36、,以及许多其他 特殊工业中的特殊参数。2: More precisely ,it is approximately proportional to the product of the field density and the current ,some nonlinearity being introduced by the distortion of the stator field due to the flux generated by the armature current .This so-called “ armature reaction ” is kept small b

37、y carefully motor design .更确切的说 , 转矩接近正比于场强与电流的乘积。电枢电流产生的磁通使 定子磁场畸变, 所以产生了某些非线性, 这叫做 “电枢反应” 。 在经周密设计的典籍中,这种电枢反应可以很小。3:Most classical control techniques were developed for linear constant coefficient systems with one input and one output (perhaps a few input and outputs .大多数经典控制技术都是带有一个输入、一个输出(也可有数个输

38、入和输出的线性、 常 系 数 系 统 而 发 展 起 来 的 。 /The language of classical techniques is the Laplace or z-transform and transfer function . 经典技术的表达语言室拉普拉斯或者 z 变换以及传递函数。 /When nonlinearities and time variations are present ,the very basic for these classical techniques is removed .一旦出现非线 性和时变性,经典技术最根本的基础就不复存在了。 /So

39、me successful techniques such as phase-plane methods ,describing functions ,and other ad hoc methods ,have been developed to alleviate this shortcoming . 诸如相平面方法、 描述函数法和其 它有关方法这样一些很成功的技术能够得以发展的原因就 是为了弥补这一短处。 /However ,the greatest success has been limited to low-order systems . 然而经典控制理论的最大成功 也是局限于低阶

40、系统中。 /The state variable approach of modern control theory provides a uniform and power-varying or constant coefficients . 现代控制理论的状态变量法提供了一 种统一、高效的方法来描述具有任意阶次、线性或非线性、 时变或常系数的各种系统。 /It provides an ideal formulation for computer implementation and is responsible for much of the progress in optimizatio

41、n theory .它也为计算机处理提供了一 种理想的表示方法,并引起了许多方面最优化理论的进展。 4:Most practical circuits may be classed as linear .Therefore ,astudy into the properties and analysis of linear circuits is of both theoretical and applied interest. 大多数实际电路可归类为线性 电路。因此,对线性电路性能和线性电路分析的研究就具有 理论和实践的双重意义。N: 1:Negative feedback also inc

42、reases the frequency bandwidth of the amplifier to which it is applied , because the gainbandwidth product of a linear amplifier is a constant , and negative feedback reduces the effective gain. 由于线性放大器 的增益带宽积是个常数,而负反馈的运用减小了有效增益, 因此,负反馈还能拓宽运用了负反馈的放大器的頻带宽度。 2: Negative feedback occurs when a portion

43、of the output signal of an amplifier is fed back and subtracted from the input signal, causing a reduction in the effective input signal. 所谓负反馈是 指输出信号的一部分被送回输入端,与输入信号相减,从而 削弱了有效输入信号, /The most important effect of this is to make the overall amplifier gain almost immune to changes in the amplifier un

44、it gain, and dependent almost entirely on the feedback network components. 负反馈的最重要作用在于使放 大器总增益不至于因基本放大器增益的改变而变化,其总增 益的大小完全取决于反馈网络的元件参数。3: Now ,another type of electrical signal ,which is becoming common , is the digital or discrete signal .当今,另一种电信号形式变得越来越常用,就是数字或者是离散信号。O: 1:One additional distincti

45、on not shown in Fig.38.1 could be made between large-scale system and small-scale system . 图 38.1中没有表示出来的另一种分类是大规模系统与小规模系 统。 /The degree of difficulty in analysis varies greatly among these system classification . 不同系统类型,对其进行分析难 度相差很大。 /These differences have motivated different methods of approach

46、. 这些差别已经促进了不同的方法的发 展。 /Modern control theory provides one of the most general approaches .现代控制理论提供了一种最一般性的方法。 2:One of the conductors is common to both sides of the bridge while the other two connect one to each side of the bridge . 三 导线中,其中一根对电桥两臂是相同的,而其它两根连在电 桥 的 两 臂 上 。 /Any change in cable tempe

47、rature will be cancelled as both sides of the bridge are changed a like amount .由于两桥臂的变化是一样的,所以电缆上的任何温度变化就 会被抵消。3:Operational amplifiers with very high gains are readily available , making the application of negative feedback on a large scale practical and inexpensive. 高增益的运算放大器是 容易得到的,这便使负反馈的使用现实而经

48、济。4:Output interface take a similar form (Fig.18.2 ,the obviousdifference being that here the flow of information is in the opposite direction. it is passed from the program to the outside world .输出接口采用相似的形式(图 18.2 , 明显的差别在于 信息流的方向相反,是从程序到外部世界。S: 1:Several factors provided the stimulus for the devel

49、opment of modern control theory :(1The necessity of dealing with more realistic models of systems .(2The shift in emphasis towards optimal control and optimal system design .(3The continuing developments in digital computer technology .(4The shortcomings of previous approaches .(5A recognition of th

50、e applicability of well-know methods in other fields of knowledge .有几个因素激励了现代控制理论的发展:(1处理 更加真实的系统模型的必要性 .(2研究重点朝向最优控制和 最有系统设计的转移 .(3数字计算机技术的不断发展 (4原 有方法的短缺 .(5对于将熟知方法在其它知识领域中应用的 广泛认同2. Should there be an uncompensated variation in the reference junction temperature ,there will be a corresponding cha

51、nge in millivolt with a resultant error in temperature measurement .例 如参考端温度的变化没被补偿,就会有相应的毫伏电压变 化,结果会导致温度测量的误差。3:Simple put ,robot hands-like robots legs ,or eyes ,or reasoningpowers-have long way to go before they can approach what the biological evolution has achieved over by the course of hundred

52、s of millions of years .简单来说,机器人的手 -如同机 器人的腿,眼睛或推理能力,在接近经过成亿年生物进化所 获得的能力之前,还有很长时间的路要走。4:Single-loop feedback systems with the structure of Fig.27.2 are often called servomechanisms because the controller usually includes a device giving considerable power amplification.具有 图 27.2结构的单回路反馈系统 , 通常称为伺服机件

53、 , 因为这种 控制器中常常包括了一个能给出相当大功率的放大装置 . 5:System models can be developed by two distinct methods .系 统 的 模 型 可 以 通 过 两 类 截 然 不 同 的 方 法 来 建 立 。 /Analytical modeling consists of a systematic application of basic physical laws to system components and the interconnection of these components . 解析建模是将物理学基 本定律系

54、统性地应用于系统各组成部分及其相互之间的关 联 关 系 进 而 获 取 结 果 方 法 。 /Experimental modeling ,or modeling by synthesis is the selection of mathematical relationship which seems to fit observed input-output data.经验 建模,或叫综合建模,是一种通过寻找数学关系而建立模型 的方法,这种数学关系应该能够与输入输出观测数据相配 合。T: 1:The armature voltage and external load torque are

55、inputs to the system ,If the are zero ,then clearly a knowledge of i(t and w(t at some value of t ,say t =0,is sufficient to allow the equations to be solved for all future values of time .电枢电压和 外负载转矩是系统的输入。假设他们是零,显然,如果知道 了某个时刻 t ,例如 t=0时的 i(t和 w(t,就可以解出方程在此 后任何时刻的数值。2:The artificial intelligence wi

56、ll enable the robot to respond to and adapt to changes in its task and in its environment ,and to reason and make decisions in reaction to those changes .人工智 能将是机器人能响应并适应其工作任务和环境变化,并且能 按照这些变化的反应进行推理和作出决定。3:The behavior of a process with respect to time defines its dynamic characteristics .Behavior n

57、ot involving time defines its static characteristics.时间过程行为显示它的动态特征, 不含时 间的行为显示它的静态特征。4:The kinds of processes found in industrial plants are as varied as the materials they produce,在工厂中所见的过程种类是随 其生产的材料而变的, /They range from the commonplace, such as loops to control flow rate ,to the large and comple

58、x ,such as distillation columns in the petrochemical industry . 所涉及的范围从比较平常的,如控制流量的环路,到大型复杂的,如石化厂的蒸馏塔。 /Whether simple or complex ,they all consist of some combination of capacity resistance and dead time 。 无论是简单还是复杂的, 它们都包 含某种容祖和迟滞时间。5:The last element of the loop is the automatic controller .Its j

59、ob is to control the measurement .环路的最后一个元件是自动控 制器, 其工作是控制测量值。 /To “ control ” means to keep the measurement at a constant ,acceptable value . “控制”意味着 将 测 量 值 保 持 在 某 一 可 接 受 的 恒 定 值 。 /All automatic controllers use the same general responses ,although the internal mechanisms and the definitions given for these responses may differ slightly from one another .所有的自动控制器都采用相 同的,普遍的响应,尽管这些响应的内部机理和含义各有差 异。6:T he mathematical tools require