济南大学自动化专业英语助考.doc

。1.11. In recent years the performance requirements for process plant have become increasingly difficult to satisfy. 近年来，对过程系统的性能改善需求变得越来越困难. 2. A further complication (复杂) is that modern processes have become more difficult to operate because of the trend toward larger, more highly integrated plants with smaller surge capacities (谐振能力) between the various processing units.更为复杂的情况是，由于现代制造业朝着规模更大,集成度更高的方向发展,而使不同的加工环节之间的协调能力更低, 所以加工过程更难控制.3. In fact, without process control it would not be possible to operate most modern processes safely and profitably (有利的), while satisfying plant quality standards.实际上，对于大多数现代工业，要满足安全、高效，产品质量的要求，没有控制系统是不可能的4. It is assumed that the inlet and outlet flow rates are identical (相同的) and that the liquid density (rho) remains consant, that is, the temperature variations are small enough that the temperature dependence of can be neglected. 假设输入和输出流量率是相等的，并且液体密度保持恒定也就是说温度变化足够小，密度对温度的影响可以忽略不计5 To determine the required heat input for the design operating conditions, we need to write a steady-state (稳态) energy balance (能量平衡) for the liquid in the tank. 要确定达到设计运行条件下的热量需求，我们需要写下槽内液体的稳态能量平衡式6 However, increased volume of tankage would be an expensive solution for an industrial plant due to the increased capital costs of the larger tank.然而，体积增加使得开支增加，会使工厂系统的解决方案变得更加昂贵. 7 It is important to make a distinction between negative feedback (负反馈) and positive feedback (正反馈). Negative feedback refers to the desirable situation where the corrective action taken by the controller tends to move the controlled variable toward the set point. 区分负反馈和正反馈很重要. 负反馈是指期望达到的形势，控制器的校正作用使得被控变量趋于给定值.8 Note that in feedforward control, the controlled variable T is not measured. 注意的是，在前馈控制中，被控变量T是没有被测量的。Plant 车间，工厂，系统 Strategy 策略 Surge capacity 谐振能力 Upset 混乱，扰乱 Process control 过程控制 Quality 质量 Stirred-tank 搅拌槽 Inlet 入口，进口 Variation 变化量 Constant 常数，恒量 Set point 设定值给定值 Terminology 术语 Gradient 梯度 Steady-state 稳态 Energy balance 能量平衡 Manual control 手动控制，人工控制 Automatic control 自动控制 Fluctuation 波动 Damp 阻尼；衰减 Feedback control 反馈控制 Negative feedback 负反馈 Positive feedback 正反馈 Feed forward control 前馈控制 Heat exchanger 热交换器 Heat loss 热损失 Perfect control 完美控制 process plant 过程系统process control 过程控制Automatic control 自动控制Manual control 手动控制，人工控制Feedback control 反馈控制Set point 设定值Controlled variable 被控变量密度 density负反馈 negative feedback正反馈 positive feedback前馈控制策略 feedforward control strategy控制器 controller1.21 The reduction of system error is merely (仅仅) one of the many important effects that feedback may have upon a system. 减少系统误差只是反馈对系统产生的重要作用之一2 In a practical control system, G and H are functions of frequency, so the magnitude of 1+GH may be greater than 1 in one frequency range but less than 1 in another.在实际的控制系统中，G和H都是频率的函数，因此1+GH的幅值在一种频段下可能增大系统的增益，而在另一频段下又可能减小系统的增益3 It can be demonstrated that one of the advantages of incorporating (包含) feedback is that it can stabilize an unstable system.可以证明，加入反馈的好处之一是能够使不稳定的系统稳定。4 The bottom line is that feedback can improve stability or be harmful to stability if it is not applied properly. 在实践中，GH是频率的函数，并且闭环系统的稳定性条件依赖于GH的幅值和相位。结论是反馈能够改进系统的稳定性，但如果使用不当，也有可能破坏稳定性.bandwidth 带宽/误差范冒 gain 增益 sensitivity 灵敏度 static-system 静态系统 magnitude 大小，幅值 phase 相角，相位 resistance 电阻，阻抗 thermal-noise 热噪声 voltage 电压，伏特数 impedance 阻抗 frequency response频率响应 Stability 稳定性 sensitivity 灵敏度Actuator 执行器 sensor 传感器 temperature 温度Flow rate 流速 pressure 压力Concentration 浓度 magnitude幅值 phase相角 closed-loop闭环 open-loop开环 model 模型 proportional比例 proportional plus derivative (PD)比例加微分 proportional plus integral (PI)比例加积分proportional plus integral plus derivative (PID)比例加积分加微分1.31 If the oscillation has a small amplitude and damps out (衰减) quickly, then the control system performance is generally considered to be satisfactory.如果振荡的幅值很小并且衰减很快，那么一般认为控制系统的运行状态是令人满意的 2 Before presenting various stability criteria, we introduce the following definition for unconstrained linear systems (无约束线性系统). 在介绍各种稳定性判据之前，我们先介绍关于无约束线性系统的定义3 Definition of stability. An unconstrained linear system is said to be stable if the output response is bounded (有界的) for all bounded inputs. Otherwise it is said to be unstable.稳定性的定义：对于一个无约束线性系统，如果对所有的有界输入，输出响应都是有界的，那么该系统是稳定的，否则就是不稳定的。4 General Stability Criterion. The feedback control system in Fig. 1.3.1 is stable if and only if all roots of the characteristic equation are negative or have negative real parts. Otherwise, the system is unstable.通用稳定性判据：图1.3.1所示的反馈控制系统是稳定的，当且仅当所有的特征方程的根都是负的或其实部是负的。否则，系统是不稳定的。5 Routh Stability Criterion劳斯稳定性判据6 A necessary and sufficient condition for all roots of the characteristic equation in Eq. (12) to have negative real parts is that : all of the elements in left column of the Routh array are positive.式（12）特征方程的所有根均具有负实部的充要条件是，劳思阵的左列的所有元素均为正值。 Criterion判据 准则Oscillatory 振动的Amplitude振幅 振荡Polynomial多项式Saturation 饱和Unconstrained 自由的 无约束的Rational function 有理函数Characteristic equation 特征方程Coefficient 系数Matrix 矩阵Unstable 不稳定地 Manipulated variable 操纵变量error 误差Process transfer function 过程传递函数Pole-zero cancellation 零极相消Self-regulating 自调节 拉氏变换 Laplace transform零点zero-point 极点 pole-point特征方程 characteristic equation 系数 parameter/coefficient偏差变量 deviation variable 1.41 Depending on the perceived deficiencies (缺乏) of the starting design, it might be necessary to change the control hardware基于所察觉的最初设计的缺陷，有可能必须改变控制的硬件.2 In principle, the flight control problem could be formulated as a general optimization problem: to minimize a mathematically specified performance index (索引、指标、指数) subject to mathematical constraints. 原则上，飞行控制问题可以被表述成一个通用的优化问题:在数学约束范围内，最小化一个指定的数学性能指标。Intuition 直觉Innovation 改革 创新Retard 延迟Methodology 方法论Constraint 约束 强制1.5 1 This activity is referred to as controller tuning or field tuning of the controller.这个活动被称为控制器整定，或控制器的现场整定。2 Flow and liquid pressure control loops are characterized by fast responses (on the order of seconds), with essentially no time delays (没有时间延迟). 流量和液压控制回路的特点是响应快速（秒级），基本上没有时间延迟。3 Disturbances in flow-control systems tend to be frequent but generally not of large magnitude.流量控制系统中的扰动较为频繁但通常幅值较小。4 Controller field tuning is often performed using trial and error procedures suggested by controller manufacturers.基于控制器生产厂家的建议，控制器的现场整定通常采用经试差法来完成。5 Step 3. Increase the controller gain Kc by small-increments (增加) until continuous cycling (循环，这里指振等幅连续) occurs after a small set-point or load change. The term “continuous cycling refers to a sustained oscillation with constant amplitude.第3步：逐步增加控制器增益Kc，使得系统输出经过一个较小设定或负载变化之后，达到连续循环. 术语“连续循环”指的是等幅振荡. 6 These tuning relations have been widely used in industry and serve as a convenient base case for comparing alternative control schemes.这些整定关系在工业中得到了广泛的应用，也为比较不同的控制方案提供一个方便的基础。Controller tuning 控制器整定Trail and error 试差法Vaporizer 蒸馏器Loop tuning 回路整定Decay ratio 衰减比Overshoot 超调Chart 图表Calibration 刻度 标度 标准Trial and error 试差法 residence time 滞留时间Decay ratio 衰减比率流量控制 flow control 液面控制 level control压力控制 pressure control 温度控制 temperature control 超调 overshoot 化学反应器 chemical reactor2.11 Atmosphere pressure is the pressure on the earths surface due to weight of the gases in the earths atmosphere and is normally expressed at sea level as 14.7 psi or 101.36 kPa.大气压指空气由于自身重力作用于地球表面的压力，通常表示为海平面大气压，14.7 psi 或 101.36 kPa.2 Absolute pressure is the pressure measured with respect to (相对于) a vacuum and is expressed in pounds per square inch absolute (psia).绝对压是相对于真空压测量到的压力，表示为磅每平方英寸 (psia).3 Gauge pressure is the pressure measured with respect to atmospheric pressure and is normally expressed in pounds per square inch gauge (psig).表压是相对于大气压测量到的压力，通常表示为磅每平方英寸 (psig)4 The Bourdon tube is normally used for measuring positive gauge pressures, but can also be used to measure negative gauge pressures. 波登管通常用于测量正值表压，但是也可以用于测量负值表压.Container 容器Metric unit 公【米】制单位Vacuum 真空 真空度 真空状态Atmospheric pressure 大气压Absolute pressure 绝缘Gauge pressure 表压Differential pressure 差压Diaphragm 膜片，膜盒 膜片 薄膜Capsule 小盒 膜合 容器Bellows 风箱 波纹管 弹簧皱纹管 膜合Bourdon tube 波灯管Silicon 硅Stainless gauge 应变仪 应变电阻Capacitance 容量 电容Semiconductor 半导体Atmospheric pressure 大气压absolute pressure 绝压Gauge pressure 表压differential pressure 差压 diaphragm 膜片Capsule 膜盒 bellow 波纹管Bourdon tube 波登管 silicon diaphragm 硅膜片英制 British system 公制 metric system差压变送器 differential pressure transmitter2.21 This unit discusses the measurement of the level of liquids and free flowing (自由流动) solids in containers (容器). 这一单元讨论容器内液体和自由流动固体的液面测量. 2 The detector is normally sensing the interface (界面) between a liquid and a gas, a solid and a liquid, or possibly the interface between two liquids. 探测器通常检测液体和气体，固体和液体，或者两种液体之间的界面. 3 Sensing liquid levels fall into two categories; firstly, single-point sensing (单点检测) and secondly, continuous level monitoring (监测). 检测液体液面可分为两类：一类是单点检测，第二类是对连续液面进行监测.4 Buoyancy (浮力) is an indirect method used to measure liquid levels.浮力是测量液面的一种间接方法5 Conductive probes are used for single-point measurements in liquids that are conductive and nonvolatile as a spark (火花) can occur. 导电电极(传感器) 用于单点液位测量，液体是导电的并且不可挥发，以防止电火花的产生. 6 Capacitive probes are used in liquids that are nonconductive and have a high and can be used for continuous level monitoring. 电容电极用于不导电并且具有很高的介电常数的液体，可以用于连续液面监测. 7 Ultrasonics can be used for single point or continuous level measurement of a liquid or a solid. 超声波(传感器)可以用于液体或固体的单点液位测量或连续液位测量. Overflow 溢出 溢流Specific weight 比重Buoyancy 浮力 浮动性Capactive probe 电容极性Nonconductive 不传导的 不到电的 非导电的Dielectric constant 介电常数Sight glass 玻璃液面计 观察玻璃 观察孔Pressurized container 带压容器 带压储罐Float 浮体 浮球 浮标 沉桶Conductive 传导的 导电的 传热的Rod 拉杆。连杆 container 容器buoyancy 浮力Capacitive probe 电容电极 Dielectric constant 介电常数 Float 浮体，浮球，浮标 浮球 float 标尺 scale电位计 potentiometer 导电电极 conductive probe电容电极 capacitive probe 2.3 1 Viscosity (粘度，粘性) is a property of a gas or liquid that is a measure of its resistance to motion or flow. 粘度是描述气体或液体对运动或流动的阻力的一种特性. 2 A viscous (粘性的) liquid such as syrup (糖浆) has a much higher viscosity than water and water has a higher viscosity than air. 粘性的液体比如糖浆，其粘度要远大于水，而水的粘度又高于空气. 3 Energy factors. Most flow equations are based on the law of energy conservation and relate the average fluid or gas velocity, pressure, and the height of fluid above a given reference point. 能量因素. 大多数流体方程基于能量守恒法，使液体或气体的平均速度，压力，以及流体高于给定参考点的高度联系起来. Velocity 速度Laminar flow 流层Turbulent flow 湍流Viscosity 粘性 黏度 内摩擦Poise 平衡剂 缓冲剂 泊（黏度单位）Centipoise 厘泊Kinematics 运动学Reynolds number R 雷诺数Energy losses 能量损失Flow rate 流率 流速Total flow 总体流量 Kinetic energy 动能 potential energy 势能2.41 Thermoelectric effect sensors rely on the physical principle that, when any two different metals are connected together, an e.m.f.,热电势效应传感器基于的物理原理是，当任意两个不同的金属连接在一起时2 Thermocouples are a very important class of device as they provide the most commonly use