专业外语教学资料 专业英语－13 introduction to control engineering.ppt

English in Electric Automation,Sunny Shen,13 Introduction to Control Engineering,dial n.刻度盘,调节控制盘 calibration n.标定, 标准化 lubrication n.润滑,注油 arrangement n.结构 wear n.磨损, 耗损 subtle a. 微妙的, 巧妙的 transducer n.变送器 hand-wheel 手轮, 驾驶盘, 操纵盘 hydraulic a. 液压的; n. 液压传动装置 pneumatic a.气动的, 气体力学的 electro-hydraulic a.电动液压的 electro-pneumatic a电动气动的 coincidence n.一致,相等 faithful a.正确的, 可靠的 fidelity n.重现精度, 真实, 正确 oscillatory a.振动的, 摆动的 align v.调准, 调整,Vocabulary,centrifugal a. 离心的; n. 离心力,离心 whilst = while sphere n.球体 counteract v.抵抗,抵消,消除 joint n.关节,铰链 keyway n.键槽 pivot n.轴,支点 link n.连杆 throttle n.节流(气)阀,风门 synthesis n.综合(物) mass n. 物质,块,堆 classic a.古典的,经典的,传统的 steer v. 驾驶,操纵,引导 servomechanism n.伺服机构,伺服系统 actuate v.激励,驱动 intimately intimeitli ad .紧密地, 直接的 academic a.纯理论的,autonomic a.自治的 grossly ad .大概, 大体上 ideological a. 思想的 morally ad .道德上, 道义上 boredom n.讨厌, 无趣 deterioration n.变化, 降低品质 ambient a.环境的 remarks rima:ks n.附注, 要点 differential pressure transducer 差压变送器 profile milling machines 仿形铣削 I.R.E.=Institute of Radio Engineers 无线电工程师学会(美已改名为IEEE),profile n.轮廓, 仿行 milling machines 铣床 gyroscope n. 陀螺仪 launcher n.发生器, 启动装置 inertial a.惯性的, 惯量的 electrolytic a.电解的 plate v.(电)镀 distillation n.蒸馏 blend v.混合, 调和, 配料 philosophy n.基本原理 analytical a. 分析的, 分解的 orifice n.测流孔, 隔板 diaphragm n.膜, 隔板 knob n.钮, 圆形把手 nomenclature n.术语 liable a.有责任的 ambiguity n.模糊, 多义,In recent times there has been a considerable advance made in the art of automatic control. 近期，在自动控制策略方面已经取得了很大的进步。 An undesirable feature which accompanies a system which has been designed to be very sensitive to speed changes is the tendency to hunt or oscillate about the final speed. The real problem in the synthesis of all systems of this type is to prevent excessive oscillation but at the same time produce good regulation. 对于被设计成对速度变化非常敏感的系统来说，一个不希望有的特性是在最终速度附近的“摆动”或振荡。所有这类系统综合的真正问题是要在获得良好的调整率的同时，防止有过大的振荡。,难句参考翻译,Regulation is defined as the percentage change in controlled quantity on load relative to the value of the controlled quantity under condition of zero load. 调整率定义为负载条件下被控量相对空载条件下被控量数值的百分比变化。 Classic work was performed by N. Minorsky in the USA in the early 1920s on the automatic steering of ships and the automatic positioning of board ships. 早在本世纪20年代，美国的N.米诺斯基在船舶的自动驾驶和舰载炮的自动定位方面完成了经典工作. He defined a servomechanism as a power amplifying device in which the amplifier element driving the output is actuated by the difference between the input to the servo and its output . 他将伺服系统定义为“由伺服系统的输入与输出的差值激励的功率放大装置，用于驱动输出”。,Even nowadays complete academic design of process control systems is virtually impossible owing to our poor understanding of the dynamics of processes. 由于我们对过程动力学缺乏了解，所以直到今天，也实质上无法得到关于过程控制的完整的理论设计。 In a simple closed-loop system, the controller is no longer actuated by the input but the error. 在简单的闭环系统里，控制器不再受输入而是受“偏差”激励。 The speed of response to changes in load is also very much faster than that of the open-loop system. 对于负载变化的响应速度也比开环系统的响应速度快得多。 A detailed description of some of the devices used in control systems will be given. 后面将给出用于控制系统的一些部件的详细说明。,The regulator, whose object is to maintain the value of some physical quantity at a fixed level in spite of disturbances, is an important example of a closed-loop system. 调节器是闭环系统的一个重要例子，其目标是即使有扰动也要将某些物理量维持为恒值。 Equally important and certainly more challenging as an exercise in engineering design is the servomechanism whose object is to follow input commands. An example of such a device is the position-control servomechanism which must reproduce at some remote point the motion applied to a handwheel located at a local command station. 在工程设计应用中，同样重要和当然是更具挑战性的任务是位置控制伺服系统，其目的是跟随输入。这种装置的一个例子是这样一种位置伺服控制系统：在远处复制施加于本地控制中心的手轮之上的运动。 The low-power error signal is used to drive an amplifier which also receives power from an external source and delivers controlled power to the motor. 小功率的误差信号用于驱动放大器，放大器还从外部电源获取功率并将被控功率传输到电动机。,It is emphasized that the object of system is to make the rotatable mass copy as nearly as possible the motion of the hand-wheel. 需要强调的是：系统的目标是，使旋转物体尽可能近似地复制手轮的运动。 Only when exact coincidence occurs does the amplifier receive zero signal and thus the motor is forced to move either one way or the other until all motion dies away. 只有当（给定输入和反馈）完全一致时，放大器接收零值信号，因此电动机向某个方向或反方向旋转直至运动逐渐消失。 A system in which oscillations build up is said to be unstable and much of the design work in control engineering is associated with producing a stable system. 工作于振荡状态的系统称为不稳定系统，控制工程的许多设计工作都与建立一个稳定系统相关。,The computer usually acts partly as a memory which is able to reproduce a variety of complicated commands in a certain sequence and partly as arithmetic device to perform subtraction and produce highly accurate error signals on reception of digitized measurements of the output positions of the various servomechanisms under its control. 计算机通常部分起存储器的作用，用于在某一序列中再生各种复杂指令，部分起到算法装置的作用，进行相减运算、并在其控制下，在数字式测量设备的接收端产生高精度误差信号，这些数字式测量设备位于各种伺服装置的输出位置。 注：最后一句直译是“在各种伺服装置的输出位置的数字式测量设备的接收端产生高精度误差信号”，定语过长，阅读时过于拗口，难于理解，翻译时断成两部分。,The slight difference between input and output position would be of such magnitude as to produce an output torque from the motor sufficient to drive the mass at the required velocity against frictional torques. 输入与输出位置的轻微差别能够达到如此的幅度，足以产生足够的电动机输出转矩，能够克服摩擦转矩后以所需速度拖动控制对象。 Another object of the position control system is that it must be capable of holding the output position equal of the command in the presence of severe load disturbances. 位置控制系统的另一个目标是它在恶劣的负载扰动下保证输出位置和命令相同。,A feedback control system is a control system comprising one or more feedback control loops ,which combines functions of the controlled signals with functions of the commands to tend to maintain prescribed relationships between the commands and the controlled signals A servomechanism is a feedback