自动化控制系统;自动化专业英语翻译
自动化控制系统
Abstract: the information age high-tech traditional industries, in the rapid development of mechanical industry automation appeared in some new technology: the movement control loop ac servo motor drive technology, computer technology and programmable controller, the movement control CARDS, etc. This paper analyzed and summarized the new technology of basic principle, characteristics and application status, etc.
Keywords: linear motor servo drive technology, computer, programmable controller, motion control
1 introduction
Information age of high-tech flow caused by the traditional industry, the profound change. As one of the traditional industry, machinery industry in this new technology revolution and product structure and production system structure is a new species, microelectronics technology, the rapid development of computer technology and information, intelligent mechanical device and power equipment, machinery industry, combining began a massive mechatronics technology revolution.
Along with the computer technology, electronic power technology and sensor technology development, the advanced countries mechtronie product emerge in endlessly. Machine tools, automotive, instrument, electrical appliances, light industrial machinery, textile machinery, packaging machinery, printing machinery, metallurgy, machinery, chemical machinery and industrial robots, more attention by all aspects of people's lives, it in improvement, improve work efficiency and save energy and reduce the material consumption, strengthen the competitiveness of the great aspects plays a role.
In the rapid development of the electromechanical integration technology, motion control technology as its key part, also an unprecedented development, and each manufacturer launched motion control of new technology, new product. This article mainly introduced the closed-loop AC Servo drive technology (Full Closed Servo Motor, AC drive technology (go), which Linear Programmable Controller (Programmable Controller is Computer, the PCC) and the movement control CARDS (Board) Motion needed several representative of new technology.
2 the closed-loop ac servo drive technology
In the rapid development of the electromechanical integration technology, motion control technology as its key part, also an unprecedented development, and each manufacturer launched motion control of new technology, new product. This article mainly introduced the closed-loop AC Servo drive technology (Full Closed Servo Motor, AC drive technology (go), which Linear Programmable Controller (Programmable Controller is Computer, the PCC) and the movement control CARDS (Board) Motion needed several representative of new technology.
Along with the computer technology, electronic power technology and sensor technology development, the advanced countries mechtronie product emerge in endlessly. Machine tools, automotive, instrument, electrical appliances, light industrial machinery, textile machinery, packaging machinery, printing machinery, metallurgy, machinery, chemical machinery and industrial robots, intelligent robots and many other categories of products every year there are new developments. Mechatronics technology has been more and more concerned by various aspects, it in improving people's life, improve work efficiency and save energy and reduce the material consumption, strengthen the competitiveness of the great aspects plays a role.
In some of the positioning accuracy and the dynamic response of the demand is higher, electromechanical product ac servo system is widely used, including digital ac servo system with digital control mode is more, but the trend is very simple, debugging, use is popular. The servo drive system of the use of advanced Digital Signal Processor (DSP) Digital Signal Processor, to the motor shaft back-end department of photoelectric encoder and on location in the drive and sampling motor between the position and speed closed-loop control system, and give full play to the high speed Digital Signal Processor (DSP), automatic gain control of the servo system, and can even load changes, the real-time tracking control system; gain Some drivers have fast Fourier transform (FFT) function, the measure of GongZhenDian mechanical equipment, and through a notch filter to eliminate mechanical resonance.
Normally, the digital ac servo system mostly in half of the closed-loop control work, namely the encoder feedback servo motor speed loop, also be for position loop. This kind of control mode for transmission chain of clearance and error cannot overcome
or compensation. In order to obtain higher control precision, should be in the final of the installation precision detection devices (such as: grating feet, photoelectric encoder, etc.), i.e. the closed-loop control. Comparison of the traditional method is: the closed-loop control servo systems only accept instruction, speed loop control loop control by the superior position controller (most of the closed-loop system is nc). This greatly increases the difficulty of the upper controller, servo system is limited. Currently, foreign already appeared a more perfect, can achieve higher accuracy of the closed-loop digital servo system, the realization of high automation equipment more easily. The control principle, as shown in figure 1.
This system has overcome the defect of half a closed-loop control system, servo drive can direct sampling in final mechanical part position feedback element (such as grating feet, magnetic grid feet, revolving encoder, etc.), as the position loop, and the motor speed feedback at only as coder. Such servo system can eliminate the mechanical transmission of gear gap, gap (e.g., etc), ball screw clearance compensation of mechanical transmission manufacturing error (such as ball screw pitch error, etc), and realize the closedloop position control functions, higher precision. And this whole closed-loop control are accomplished by servo drive, without increasing the burden and supervisory controller in its growing industry automation equipment and developed, and start using this kind of servo system.
In some of the positioning accuracy and the dynamic response of the demand is higher, the mechtronie product in communication
This system has overcome the defects of the closed-loop system and the position loop, sampling can directly from in final position on the mechanical components (such as
gratings' feedback, magnetic gate ruler, revolving encoder, etc), and the motor speed loop at only as encoder, the feedback can eliminate all the gap existing in machinery, and the servo system, but also can appear on the mechanical transmission error compensation, achieve real closed-loop function, achieve the high position control. And this whole closed-loop control are accomplished by drive, without increasing the burden of supervisory controller.
Owing to the closed-loop ac servo system can get high precision, and does not need to increase the complexity of supervisory control system. So it is widely used in nc machine tools, precision CNC equipment design, etc.
This system has overcome the defect of half a closed-loop control system, servo drive can direct sampling in final mechanical part position feedback element (such as grating feet, magnetic grid feet, revolving encoder, etc.), as the position loop, and the motor speed feedback at only as coder. Such servo system can eliminate the mechanical transmission of gear gap, gap (e.g., etc), ball screw clearance compensation of mechanical transmission manufacturing error (such as ball screw pitch error, etc), and realize the closedloop position control functions, higher precision. And this whole closed-loop control are accomplished by servo drive, without increasing the burden and supervisory controller more industry
In the numerical control lathe, especially in computer nc machine tools, because it has closed servo drive system work reliably, high precision and strong anti-interference, relative to the open-loop servo drive system is more commonly used. But due to the increased closed servo drive system, feedback, comparative position detection, and step into the open loop system, its structure is more complex, debugging is relatively more difficult.
A closed-loop servo drive system, the actuator
Along with the development of numerical control technology, the requirement of actuators are summed up and increasingly high, basically have the following:
(1) to minimize the rotational inertia of the motor, in order to improve the system of fast dynamic response,
(2) improve motor overload ability to adapt often appear the impact of the phenomenon,
(3) improve speed and stability operation of motor, to ensure the uniformity of speed
servo system accuracy.
Due to the particularity of mechanical processing, general motors can not meet the nc machine tools for servo control requirements. At present, in the nc
The machine is widely used in the dc servo motor and ac servo motor.
1 dc servo motor
The dc servo motor was used in machine tool servo system is a kind of actuators. In the servo system used in the dc servo motor servo motor for dc motors, such as low inertia and wide speed motor, etc. Although these servo motor, have the features of different structure, but its working principle and dc motor are similar.
(1) low inertia dc servo motor. Main whether slot dc servo motor armature and other types of motor. No slots dc servo motor armature the working principle and structure of the same dc motor, the difference and features are: the armature core is smooth without trough, the armature winding circles with epoxy resin curing and binder in the armature core on the surface, the length and diameter of the armature five times more than in the air-gap size than the average dc motor is 10 times greater than. Its output power in dozens of watts to 10 kW. Mainly used for fast movement, power system.
(2) wide speed dc torque motor. With the motor torque method to improve to improve the dynamic performance. Its structure and general dc motor, usually by similar separate-excited him. Almost all https://www.sodocs.net/doc/e36040392.html,bined with armature control. It has the following features:
(3) dc servo motor control principle of pulse width. The dc servo motor speed adjustment method is mainly to adjust the armature voltage. Currently the most widely used methods are transistors pulse width omdulatros - dc motor speed (PWM - M). It has the fast response, high efficiency, wide range of speed and noise pollution is small, simple and reliable.
Pulse width modulator, using the basic working principle of switch power transistor, dc voltage must be converted into the frequency voltage, add to the dc motor armature. Through each pulse width control, wave the armature voltage change of average, adjust the speed of the motor. Figure 5-9 - M system of PWM is working principle diagram. Figure 5-9 will set the switch (a) to close, disconnect K cycle, start-up and shut-down cycle is T. In a period of time, the time for τ, disconnect for T -
respectively. If the power supply voltage U plus is constant, add to the electric power of the armature voltage waveform is a square column, its height for U,
Width for τ, as shown in figure 5-9 (b). It is the average
（5-2
Type in the delta = τ/T, called conduction rate. When T unchanged, as long as the continuous change, can make the armature voltage average (namely dc component) from 0 to U, and continuous changes continually changing motor speed. The actual system with high PWM - M triode switch K. 2 ac servo motor
Ac servo motor drive is the latest development of new servo system, the machine is driven system for a new trend. The dc motor drive system ZhengLiuZi brush and often repair, motor and using environment size restriction shortcomings. It can speed in a wide range of torque, produce the ideal of simple structure, reliable operation, used for numerical control machine tool, to drive system for precision into position control.
The working principle of ac servo motor with two phase asynchronous motor is similar. However, due to it in the nc machine tools as actuators, ac signal conversion for the angular velocity or on the rotor speed requirements, so how can reflect the control signal phase, it is not turning control signals. Especially when it has in turn, if control signals disappear, it immediately stop turning. But ordinary induction motors turn, if the control signal to disappear, it often can't stop immediately and will continue to roll.
Also by ac servo motor stator and rotor. The stator windings and control winding is excitation, the difference in the space of two winding Angle of 90 ° electricity. If the two phase windings in amplitude and phase equal 90 ° Angle of the electric motor on voltage, the symmetry of air gap in the circular rotating magnetic field. If two voltage amplitude range for 90 ° or phase Angle of electric, magnetic fields produced by a rotating magnetic oval. Add in the control signal is different, the winding magnetic field generated by the ellipse is different also. For example, load torque must change control signals, and can change the ellipse, magnetic control servo motor speed. Ac servo motor control mode has 3 kinds: amplitude and phase control amplitude and phase hybrid control
3 linear motor drive technology
General motors is turning to work. But with rotating motor drive traffic tools (such
as electric locomotive and city in the trolley, etc) need to do with rotating linear motion of the motor driving machine parts also should make linear motion. This will need to increase the rotation movement into a set of linear motion can directly use device. The motor to drive straight movement, eliminating this suit? Several decades ago, people put forward this problem. Now has made a straight-line movement of the motor, linear motor.
Linear motor principle is not complicated. Imagine an induction motor rotate along the movement direction of the radius and flattening dividing, it became a linear induction motor (chart) in the linear motor, equivalent to rotate the motor stator, called primary, The equivalent of motor rotor spinning, subprime. Primary zhongtong to exchange, subprime on electromagnetic force under the action of linear motion along the primary do. Then primary do very long, extends to the movement of the need to achieve, but does not need so long subprime. Actually, linear motor can regard primary do very long, also can make long; secondary Can both primary and secondary mobile, fixed fixed, junior secondary also can move.
Linear motor is a new kind of motor, in recent years, wide application. Maglev train is driven by motor.
Maglev train is a kind of brand-new. Generally, because the train wheel and rail, limit the friction between the speed increase, it can reach the highest speed than 300km/n. maglev train, with magnetic suspension is to train and guide, by reducing friction, from contact, improve speed. By the linear motor train traction. Linear motor in the ground level, a fixed extends far to guide together, Another level installation on the train to exchange links. Primary, train the guide. Train is equipped with magnets (some fat&oil linear motor coil magnet), with the train when motion, make in the ground wire (or metal plates induced current in the magnetic induction current, and trains the magnet (or coil) of the electromagnetic force between the train is suspended. The advantages of suspension trains is running smoothly, no turbulence, low noise, small, as long as the traction for thousands of power can make kw suspension speed of trains to 550km/h. suspension trains deceleration, magnetic field changes, also reduced, magnetic induction current abate, causing levitation force trains were suspended. Equipped with a wheel device, it's like aircraft wheel, in the procession, timely income can train stops down to support the train.
To make the quality of the huge magnetic levitation train on, need strong magnetic field, the practical need with HTS windings such strong magnetic field.
Linear motor except for maglev train, also widely used in other aspects, such as system, electrical QiChui, electromagnetic mixer etc. In China, the linear motor is also gradually get promotion and application of the principle of linear motor. Though not complicated, but in the design and manufacturing has its own characteristics, the product is still not mature, motor that further research and improvement.
Linear motor servo system in the application in the world, in recent years has also get attention, machine tool industry in western industrialized region and a "hot" linear motor.
The machine adopts feeding system, in line with the direct drive motor rotate motor drive the biggest difference is cancelled from motor to workbench (dragging plate) between mechanical transmission link, the machine into the length of the transmission chain to zero, the transmission way has been called the "zero transmission". Because of this "zero" manner, driving the rotating motor driving mode can achieve performance index and advantages.
1.the high response system directly cancelled due to some of the response time constant of mechanical transmission parts (such as ball screw, etc.), make whole closed-loop control system dynamic performance greatly improve sensitive reaction.
2 precision linear drive system cancelled due to the ball screw transmission mechanism of such errors and reduce the gap and the interpolation of transmission system lags movement of the tracking error. Through the line position detection
In 1987 the International electrotechnical commission (Electrical)
issued by the International aid of PLC in the draft standards PLC made below definition:
"PLC is a specialized in industrial environment design and application of the electronic device digital computing operations. It can be used for the storage, programming in its internal logic operation sequence execution, storage, timing, counting and arithmetic operation instruction, and through digital or analog input and output, the control of various types of machinery or production process. PLC and related peripheral equipment should be easy and industrial control system according to form a whole, easy to expand its functional principle and design.
The characteristics of PLC
(1), high reliability and anti-interference ability
The traditional relay control system USES a lot of time relay, middle relays. The poor, easy contact fault occurs. Instead of using the software of PLC relay and time relay, between left and the input and output of the related hardware, can reduce a connection to the relay control system of 1/10 ~ 1/100, because of the failure caused by poor contact point is greatly reduced.
High reliability is the key performance of electrical control equipment. PLC with modern large scale integrated circuit technology, adopting strict production process manufacturing, internal circuit adopted advanced anti-interference techniques, and has high reliability. Such as mitsubishi company production of F series PLC MTBF $30 million hours. Some use redundancy CPU PLC is the average time longer trouble-free. The machine from PLC, using PLC circuit control system, and the same form of relay contact system, electrical wiring and compared to switch contacts have one hundreds and even thousands of fault is greatly reduced. In addition, PLC hardware malfunction with function, malfunction can timely warning message. In software applications, users can also into outer device of fault diagnosis procedure,
第九讲高中英语翻译技巧与能力训练(上)[讲义]
高考英语翻译技巧与能力训练 高考英语中的翻译（中译英）题要求考生能应用所学过的语法和词汇来准确地表达思想，是一种要求相当高的考查形式。要求考生把中文的句子译成通顺的、语法结构正确的、符合英语表达习惯的英语句子，并能准确地传达中文句子中的每一个信息。该题型全面地考查学生英语词汇、语法等知识的综合运用能力，它对学生的动词时态、语态、名词的单复数、冠词、形容词、副词、介词等应用能力，还对学生的词组、句型、句子结构等进行了全面考查。翻译不仅在高考英语主观题中占不小的比例，而且翻译能力还直接影响考生在作文中的表现。 高考评分标准: 1．每题中单词拼写、标点符号、大小写错误每两处扣一分；2．语法错误（包括时态错误）每处扣一分；3．译文没用所给的单词扣一分。 如何才能提高中译英水准，在高考中获得理想的分数呢？考生除了必须具备比较扎实的语言基础外，关键还在于学会总结规律，找准中译英的切入点。 一、分析句子结构、寻找合适的句型 中文必须仔细读，一定要看的就是题目给我们的关键字或关键的词组，也就是我们常说的key words。尤其是最后两句翻译句子，它们大都在句子结构上提高了难度。读什么？读出句子结构：对于简单句，辨别出主谓宾，分清定语、同位语和状语；对于并列句，记住两个语法意义上独立的分句，须由连词连接起来；对于复合句，须区分定语从句，名词性从句以及状语从句。一般来说，中译英的句型可分为三大类：1.简单句；2.并列句；3.复合句；同时我们也要注意非谓语动词及其他一些特殊结构。回顾近几年的高考试题时，也不难发现试题中考了一些特殊句式。如：It句型(近几年考得较为频繁)、倒装句、with结构。 例1: 昨天我的电脑坏了。(wrong) 解析：本题考查：1)简单句There be结构；2)wrong的用法；3)中英文表达的差异。 译句：There was something wrong with my computer yesterday. 例2: 遇到困难的时候，我们需要的不是彼此埋怨，而是互相帮助。(not…but) 解析：本题考查：1)复合句：when引导的状语从句；what引导的主语从句；2)not…but结构；3)“彼此埋怨”的英文翻译。 译句：When(we are)in difficulty/When we meet with difficulties/When we have difficulties ,what we need is not to blame each other but to help each other. 例3：我们能做什么来阻止这种疾病蔓延呢？（prevent） 分析：如果有学生没有读全中文原句的话，就很有可能看成是以前所做的“我们要做些什么来阻止这种疾病的蔓延”，而译为We should do something to prevent the spread of this disease.因为这个原因而造成扣分，就太不应该了。 译句：What can we do to prevent the spread of this disease? 例4：他很有可能通过自己的努力得到驾驶执照。（likely） 译句：He is likely to get the driving license with his own efforts. 分析：有些学生一看到有可能，就会想到自己比较熟悉的possible，想当然地翻译成It is possible that…的结构。其实，学生对likely这个key word的使用也是会的，完全能够使用be likely to do或It’s likely th at…的结构。 例5：上海近几年经历了许多变化，如今已成为世界闻名的经济中心。（go through） 分析：乍一看，学生很容易轻易下笔，Shanghai has gone through…,it has become…，这已成为很多学生的一个习惯，句子和句子中随便用逗号隔开，英语不像中文，必须要考虑到句子的结构，逗号也不能随意使用。而此句中，就要想到用并列句中的连接词and来连接两个成分。
自动化专业英语考试翻译
PART 3 Computer Control Technology UNIT 1 A 计算机的结构与功能 这一节介绍计算机的内部体系结构，描述了指令如何存储和译码，并解释了指令执行周期怎样分解成不同的部分。 从最基本的水平来讲，计算机简单执行存储在存储器中的二进制编码指令。这些指令按照二进制编码数据来产生二进制编码结果。对于通用可编程计算机，四个必要部件是存储器、中央处理单元（CPU，或简称处理器），外部处理器总线，输入/输出系统，正如图 3-1A-1所示。 外部处理器总线 存储器CPU输入/输出 图 3-1A-1 计算机的基本元件 存储器储存指令和数据。 CPU读取和解释指令，读每条指令所需的数据，执行指令所需的操作，将结果存回存储器。CPU所需的操作之一是从外部设备读取或写入数据。这利用输入/输出系统来实现。 外部处理器总线是一套能在其他计算机部件之间传送数据、地址和控制信息的电导线。 存储器 计算机的存储器是由一套连续编号的单元所组成。每个存储单元是一个能存二进制信息的寄存器。单元的编号称为地址。初始地址为0。制造商定义处理器的一个字长为单元的整数长。在每个字中，各位表示数据或指令。对于英特尔8086/87和摩托罗拉MC68000微处理器来说，一个字是16位长，但每个存储单元仅为8位，因此两个8位单元来存取获得一个数据字长。
为了使用存储器中的内容，处理器必须取来右边的内容。为了完成这一次读取，处理器把所需单元的二进制编码地址放到外部处理器地址总线的地址线上，然后，存储器允许处理器读取所寻址的存储单元的内容。读取存储单元的内容的这一过程并不改变该单元的内容。 存储器中的指令存储器中的指令由CPU取来。除非发生程序转移，它们按在存储器中出现的顺序来执行。用二进制形式所写的指令叫做机器语言指令。一种得到（指令）有效形式的方法是将（这些）位分成段，如图3-1A-2所示。每一段都包含一个不同类型信息的代码。 在简单的计算机中，每条指令可分为四段，每段有四位。每条指令包括操作代码（或操作码，每条指令有唯一的操作码）、操作数地址、立即数、转换地址。 在一个实际的指令集中，有很多指令。也有大量的存储单元来存储指令和数据。为了增加存储单元的数目，如果我们使用同样的方法，地址段的指令一定长于16位。除了增加指令长度外，还有很多增加微处理器寻址范围的方法：可变指令段、多字指令、多寻址模式，可变指令长度。我们不将详细讨论它们。 存储数据数据是存储器中代表代码的信息。为了有效利用存储空间和处理时间，大多数计算机提供了不同长度和表示方法的处理数据能力。能被处理器识别的各种不同表示称作数据类型。常用的数据类型有：位、二进制码、十进制数字（4位字节，BCD）、字节（8位）、字（2个字节）、双字（4个字节）。 有一些处理器提供了可处理其他数据类型。例如单精度浮点数据类（32位）和双精度浮点数据（64位）等的指令。还有另一类的数据–––特征数据。通常也表示为8位。在标准键盘上，每个计算机终端键和键的组合（例如shift和control功能键）有定为美国信息交换标准码的7位码。 存储器类型在数字控制系统的应用中，我们也关注不同存储技术的特征。对主存储器来说，我们需用它临时存储信息，并逐次地从不同单元写入或获得信息。这种类型的存储器称作随机访问存储器（RAM）。在某些情况下，我们不想让存储器中的信息丢失。因此我们愿使用特殊技术写入存储器。如果写入只在物理改变连接时才能实现，那么这种存储器称为只读存储器（ROM）。如果相互连接的模式可由程序设定，那存储器叫做可编程只读存储器（PROM）。如果需要实现改写的情况，我们有可擦的可编程只读存储器（EPROM）。电可擦除的PROM缩写为EEPROM。
科技英语翻译专业词汇-材料
Materials Science and Engineering arc welding 电弧焊 calcinations 煅烧 casting 熔铸 ceramic 陶瓷 chemical properties 化学性能 cold brittleness 低温脆性 colour liquid crystals 彩色液晶 congruent compound 合熔化合物 constant-deformation tests 定变形试验 Creep Strength 潜变强度 crystal pattern 晶体结构 data quartz fiber 数据石英光纤 die casting 拉模铸造 drawing & stamping 延轧 Dynamics of Forging System 锻压系统动力学 Edge Finish 边缘处理 Engineering Materials 工程材料 nano-material 纳米材料 ceramic 陶瓷 polymer 集合物 composite material 复合材料 biomaterial 生物材料semiconductor 半导体 conductor 导体 insulator 绝缘体 synthetic fabrics 合成纤维microstructures 显微结构 periodic table 周期表 Equipment for Heating Processing 热处理设备 Fatigue Test 疲劳测试 Features of Metal 金属的特性 Ferrous & Non Ferrous Metal 铁及非铁金属 forging 锻造 foundry 铸造 High Polymer Material & Processing 高分子材料及加工Impact Test 冲击测试 Intermetallic compound 金属间化物 Ionic Solids 离子晶体 Magnetic Transformation 磁性变态 Mechanic Testing of Engineering Materials 工程材料力学性能的测定Mechanical Property of Metal 金属机械性能 Metal Cutting Machine Tool 金属切削工具 Metal Erosion & Protection 金属腐蚀及防护 Metal Material Science 金属材料学 Metallic Solids 金属晶体Metallographic Techniques 金相技术Metallography 金属学 Metallography & Heat Treatment 金属学与热处理
论文：浅析英语翻译能力提升的障碍和策略
论文：浅析英语翻译能力提升的障碍和策略摘要：翻译能力是英语综合能力的重要组成部分，也是英语专业学生必需具备的基本能力。要全面提升英语翻译能力，需要了解英汉两种文化的差异性，具备深厚的语言功底，掌握熟练的翻译技巧。 关键字：英语翻译能力；提升；障碍；策略 中西文化差异是影响英语翻译能力提升的重要因素，除了文化因素外，英语翻译能力的提升还受到其他因素的影响，本文将进一步的展开叙述影响英语翻译能力提升的障碍及其相应的策略。 一、影响英语翻译能力提升的障碍 1．中西文化的差异性容易造成英语翻译误会 英语翻译就是汉语和英语相互转换的过程，这个过程不仅仅是一种语言现象，也体现了跨文化现象。具体来说，中西方的文化差异体现在文化传统、生活习惯、价值观念和思维方式等方面，而这些层面的差异性往往会造成人们对同一事物有着不同的理解和解释，因此不同文化的差异性容易造成英语翻译的误会。比如，生活中最常见的信封的写法，在中国，习惯的书写顺序是国名，省、市、县、街道，最后才是收信人姓名。而在西方国家信封的书写顺序恰好相反。因此在学习英语知识的同时，需要更加注意对英语文化知识的了解和掌握。
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小议科技英语翻译技巧
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科技英语中专业术语的翻译
科技英语中专业术语的 翻译 集团文件版本号：（M928-T898-M248-WU2669-I2896-DQ586-M1988）
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第二部分 控制理论 第1章 1.1控制系统的引入 人类控制自然力量的设计促进人类历史的发展,我们已经广泛的能利用这种量进行在人类本身力量之外的物理进程?在充满活力的20世纪中,控制系统工程的发展已经使得很多梦想成为了现实?控制系统工程队我们取得的成就贡献巨大?回首过去,控制系统工程主要的贡献在机器人,航天驾驶系统包括成功的实现航天器的软着陆,航空飞机自动驾驶与自动控制,船舶与潜水艇控制系统,水翼船?气垫船?高速铁路自动控制系统,现代铁路控制系统? 以上这些类型的控制控制系统和日常生活联系紧密,控制系统是一系列相关的原件在系统运行的基础上相互关联的构成的,此外控制系统存在无人状态下的运行,如飞机自控驾驶,汽车的巡航控制系统?对于控制系统,特别是工业控制系统,我们通常面对的是一系列的器件,自动控制是一个复合型的学科?控制工程师的工作需要具有力学,电子学,机械电子,流体力学,结构学,无料的各方面的知识?计算机在控制策略的执行中具有广泛的应用,并且控制工程的需求带动了信息技术的与软件工程的发展? 通常控制系统的范畴包括开环控制系统与闭环控制系统,两种系统的区别在于是否在系统中加入了闭环反馈装置? 开环控制系统 开环控制系统控制硬件形式很简单,图2.1描述了一个单容液位控制系统, 图2.1单容液位控制系统 我们的控制目标是保持容器的液位h 在水流出流量V 1变化的情况下保持在一定 可接受的范围内,可以通过调节入口流量V 2实现?这个系统不是精确的系统,本系 统无法精确地检测输出流量V 2,输入流量V 1以及容器液位高度?图2.2描述了这 个系统存在的输入(期望的液位)与输出(实际液位)之间的简单关系, 图2.2液位控制系统框图 这种信号流之间的物理关系的描述称为框图?箭头用来描述输入进入系统,以及
机械工程专业英语翻译合集
1.我们可以把钢再次加热到临界温度以下的某一温度，然后在慢慢让其冷却。We can heat the steel again to a temperature below the critical temperature, then cool it slowly. 2.无论任何简单的机床，都是由单一元件即通称为机械零件或部件组成的。However simple, any machine is a combination of individual components generally referred to as machine elements or parts. 3.这些金属不都是好的导体。 All these metals are not good conductors. 4. 在做带电实验的时候，再怎么小心都不为过。 You can't be too careful in performing an experiment. 5.利用发电机可以把机械能转变成电能。 The mechanical energy can be changed back into electrical energy by means of a generator or dynamo. 6.假定电源输入的电压保持不变。 Assume that the voltage input of the power supply remains the same. 7.化石燃料是发电过程中最为频繁使用的能源。 Fossil fuels are most frequently used source daring the power generation process. 8单个机械零件的可靠性成为评估整台机器使用寿命的基本因素。 The individual reliability of machine elements becomes the basis for estimating the overall life 9.说我们生活在一个电子时代，这一点都不夸张。 It's no exaggeration to say that we live in an electronic age. 10.发动机的转速不应超过最大允许值。 Engine revolution should not exceed the maximum permissible. 11.如能从大型核电站获得成本极低的电力，电解氢的竞争能力就会增强。（Electrolytic hydrogen）。 If extremely low-cost power were ever to become available from large nuclear power plants, electrolytic hydrogen would become competitive. 12.电子技术提供了一种新的显示时间的方法。 A new way of displaying time has been given by electronics. 13.远距离输电需要高压，安全用电需要低压。 High voltage is necessary for long transmission line while low voltage for safe use. 14.铝的电阻大约是同等尺寸的铜的1.5倍。 The resistance of aluminum is approximately half again as great as that of copper for the same dimensions = size 15.In fact,it is impossible for no force to be exerted on a body,since in this world everything is subject to the for ce of gravity. 事实上，物体不受外力作用是不可能的，因为在这个世界上任何物体都要受到重力的作用。 16.In a thermal power plant,all the chemical energy is not