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2021年1月12日发(作者：阎逊初)
Unit1 Metals
The use of metals has always been a key factor in the
development of the social systems of man. Of the
roughly 100 basic elements of which all matter is
composed, about half are classified as metals. The
distinction between a metal and a nonmetal is not
always clear-cut. The most basic definition centers
around[以…为中心] the type of bonding existing
between the atoms of the element, and around the
characteristics of certain of the electrons[某种电
子] associated with these atoms. In a more practical
way, however, a metal can be defined as an element
which has a particular package of properties.
Metals are crystalline[adj.晶体的] when in the solid
state and, with few exceptions[极少例外] (e.g.
mercury), are solid at ambient[周围环境的]
temperatures. They are good conductors of heat and
electricity and are opaque[不透明的] to light. They
usually have a comparatively high density. Many
metals are ductile[柔软的；易延展的]-that is, their
shape can be changed permanently[永久地，长期不变地]
by the application of a force without breaking. The
forces required to cause this deformation and those
required to break or fracture a metal are
comparatively high, although, the fracture forces is
not nearly[ =far from,much less than] as high as would
be expected from simple consideration of the forces
required to tear apart the atoms of the metal.
One of the more significant of these characteristics
from our point of view is that of
crystallinity[crystallinity [,krist'linti]]. A
crystalline solid is one in which the constituent
atoms are located in a regular three-dimensional
array as if they were located at the corners of the
squares of a three-dimensional chessboard[n. 棋盘].
The spacing of the atoms in the array is of the same
order as the size of the atoms, the actual spacing
being a characteristic of the particular metal. The
directions of the axes of the array define the
orientation of the crystal in space. The metals
commonly used in engineering practice are composed of
a large number of such crystals, called grains[晶粒].
In the most general case[一般情况下], the crystals of
the various grains are randomly oriented in space. The
grains are everywhere in intimate contact with one
another and joined together on an atomic scale. The
region at which they join is known as a grain boundary.
An absolutely pure metal (i.e.[也就是] one composed
of only one type of atom) has never been produced.
在人类社会的发展中，金属的
应用起着关键性的作用。构成
物质的大约100种基本元素中，
大约有一半为金属。金属和非
金属之间的区别不是特别明
显。最基本的定义集中在元素
原子间存在的连接形式和与这
些原子相关联的电子的某些特
性。然而，在实际应用中，可
以将具有某些特性集合金属定
义为某种元素。
除了少数例外金属在常温下是
固态的。它们是热和电的良导
体，不透光。它们往往具有较
高的密度。许多金属具有延展
性，也就是说，在不被破坏的
情况下它们的形状在外力的作
用下可以发生变化。引起永久
变形所需的力和最终使金属断
裂所需的力相当大，尽管发生
断裂所需的力远没有像所预期
的撕开金属原子所需的力那么
大。
从我们的观点来看，在所有的
特性中结晶性是最重要的。结
晶体是这样一种结构，组成它
的原子定位在规则的三维排列
中，仿佛位于三维棋盘的方格
的角上。原子间距随着原子大
小呈规律性变化，原子间距是
金属的一种特性。三维排列的
轴线决定了晶体在空间中的方
向。在工程实践中应用的金属
由大量的晶体组成，这些晶体
称之为晶粒。在大多数情况下，
晶粒在空间中是自由排列的。
在原子范围内，晶粒之间相互
接触紧密结合。晶粒之间连接
区域被称为晶界。
绝对纯净的金属从来也没有被
生产出来过。即使绝对纯净的
Engineers would not be particularly interested in
such a metal even if it were to be produced, because
it would be soft and weak. The metals used
commercially inevitably[不可避免地] contain small
amounts of one or more foreign elements, either
metallic[metallic [mi'tlik, me-]adj. 金属的，含金属
的] or nonmetallic. These foreign elements may be
detrimental[有害的], they may be beneficial, or they
may have no influence at all on a particular property.
If disadvantageous, the foreign elements tend to be
known as impurities[杂质]. If advantageous, they tend
to be known as alloying elements[合金元素]. Alloying
elements are commonly added deliberately[故意地，蓄
意地] in substantial[adj. 大量的；实质的；内容充实
的substantial evidence:实（质）体证据|实质性证据|
实质证据substantial order:大宗订单|大订单] amounts
in engineering materials. The result is known as an
alloy.
The distinction between the descriptors “metal” and
“alloy” is not clear-cut. The term “metal” may be
used to encompass both a commercially pure metal and
its alloys. Perhaps it can be said that the more
deliberately an alloying addition has been made and
the larger the amount of the addition, the more likely
it is that the product will specifically be called an
alloy. In any event[无论如何，不管怎样], the chemical
composition of a metal or an alloy must be known and
controlled within certain limits if consistent[一致
的] performance is to be achieved in service. Thus
chemical composition has to be taken into account when
developing an understanding of the factors which
determine the properties of metals and their alloys.
Of the 50 or so metallic elements, only a few are
produced and used in large quantities in engineering
practice. The most important by far is iron[铁], on
which are based the ubiquitous[普遍的，无处不在的]
steels and cast irons (basically alloys of iron and
carbon). They account for about 98% by weight of all
metals produced. Next in importance for structural
uses (that is, for structures that are expected to
carry loads) are aluminum[铝], copper, nickel, and
titanium[ [tai'teinim, ti-]n. [化]钛（金属元素）].
Aluminum accounts for about 0.8% by weight of all
metals produced, and copper about 0.7%, leaving only
0.5% for all other metals. As might be expected, the
remainders are all used in rather[相当] special
applications. For example, nickel alloys are used
principally[主要地] in corrosion-and heat- resistant
applications, while titanium is used extensively[广
泛地] in the aerospace industry because its alloys
金属可以生产出来，工程师们
对它们也并不会特别感兴趣，
因为它们很柔软、脆弱。实际
应用中的金属往往都包含着一
定数量的一种或多种外来金属
或非金属元素，这些外来元素
可能是有害的也可能是有益的
或者它们对某种特定的属性没
有影响。如果是有害的，这些
外来元素被认为是杂质。如果
是有益的，它们被认为是合金
元素。在工程材料中往往被特
意地加入一定数量的合金元
素。得到的物质被叫做合金。
金属和合金区别不大。金属这
个词可以包括工业用纯金属和
它的合金。也许可以这样说，
合金元素越故意的被添加，被
添加的合金元素的量越大，那
么生产出来的产品越倾向于被
称之为合金。不管怎样，如果
想使一种金属或合金在使用中
表现出稳定一致的特性，在其
中添加何种化学成分，它的量
多大都应该在控制范围之内。
因此，当想了解决定金属和合
金性质的因素时，应充分考虑
它们的化学组成。
在50种左右的金属元素里，工
程实践中只有少数金属被大量
生产和使用。到目前为止最重
要的是铁，以它为基础构成了
处处可见的钢和铸铁。（主要由
铁和碳构成的合金）它们的重
量占所有生产出来的金属重量
的98%。在结构应用（也就是说，
可以承受载荷的结构）中居于 其次位置的是铝、铜、镍和钛。
在所有的金属产量中，铝占
0.8％，铜占0.7％，剩下的占
0.5％。剩下的金属用于相对特
殊的用途。例如，镍合金主要
用于抗磨损和耐高温的用途，
由于钛合金具有高强度和低密
度的综合特性，钛被广泛应用
于航空工业中。镍合钛有高成
have good combinations of high strength and low
density. Both nickel and titanium are used in
high-cost, high-quality applications, and, indeed,
it is their high cost that tends to restrict their
application.
Unit2 Selection of Construction Materials
There is not a great difference between “this” steel
and “that” steel; all are very similar in mechanical
properties. Selection must be made on factors such as
hardenability[n. 可硬化性；淬硬性], price, and
availability[是产品在被调用时能够运行（即未处于失效
或修复状态）的概率。此量度考虑了产品的可靠性（多久
会失效）和可用性（多久能被修复）。 ], and not with the
idea that “this” steel can do something no other can
do because it contains 2 percent instead of 1 percent
of a certain alloying element, or because it has a
mysterious[adj. 神秘的；不可思议的；难解的](神秘的，
不可思议的) name. A tremendous[adj. 极大的，巨大的；
惊人的] range of properties is available in any steel
after heat treatment; this is particularly true of
alloy steels.
Considerations in fabrication(制造)
The properties of the final part (hardness, strength,
and machinability[n. 切削性；机械加工性]), rather
than properties required by forging, govern the
selection of material. The properties required for
forging have very little relation to the final
properties of the material; therefore, not much can
be done[无论做什么都是白费力，都改变不了既定的现
实] to improve its forgeability. Higher-carbon steel
is difficult to forge. Large grain size is best if
subsequent heat treatment will refine the grain size.
Low-carbon, nickel-chromium(铬) steels are just
about as plastic at high temperature under a single
520-ft·lb(1 ft·lb=1.35582J) blow[at a single blow=
at one blow
at a single blow:一下子|一举|一击] as plain steels of
similar carbon content. Nickel decreases
forgeability of medium-carbon steels, but has little
effect on low-carbon steels. Chromium seems to harden
steel at forging temperatures, but vanadium[](钒) has
no discernible(可辨别的) effect; neither has the
method of manufacture any effect on high- carbon
steel.
Formability
The cold- formability of steel is a function(功能) of
its tensile strength combined with ductility. The
tensile strength and yield point must not be high or
too much work will be required in bending（弯曲）;
likewise（同样地）, the steel must have sufficient
本和高质量的使用特性，事实
上，它们高的成本限制了它们 的应用。
在钢之间没有太大的区
别；所有的钢在机械性能方面
都是近似的。它们的选取标准
是诸如脆硬性，价格，和可用
性等。不仅仅是因为这种钢含
有2％的合金元素另一种钢含
有1％而使前者具有了后者没
有的某些能力，或者是某种钢
具有神奇的名字。经过热处理
后，任何一种钢都具有大范围
的特性；这种性质同样在合金
钢中存在。
关于加工的考虑
最后零件的特性（硬度、
强度和可加工性）而不是锻造特性决定了材料的选择。可锻
性与材料的最后特性联系不
大；因此，提高金属的可锻造性价值不大。高碳钢很难锻造。
如果在随后的热处理过程进行
细化，大尺寸晶粒是最好的。
在高温下低碳，镍铬合金
钢在受到520-ft·lb的冲击下
表现出与相同碳含量普通钢几
乎同样的塑性。镍减少了中碳
钢的可锻性，但对低碳钢影响
不大。铬在锻造温度下时使钢
硬化，但钒没有明显的效果；
两种加工方法对高碳钢没有影
响。
成形
钢的冷成形是它的拉伸强
度和延展性相结合的结果。拉
伸强度和屈服点不能太高否则
在发生弯曲时需要做很多工
作；与之相类似，钢应该有高
（充足的） ductility to flow to the required shape
without cracking. The force required depends on the
yield point, becausedeformation starts in the plastic
range above the yield point of steel. Work-hardening
also occurs here, progressively（日益增多地）
stiffening（使变硬） the metal and causing difficulty,
particularly（独特的，显着的） in the low-carbon
steels.
It is quite interesting in this connection（关于这
一点，就此而论） to discover that deep draws can
sometimes be made in one rapid operation that could
not possibly be done leisurely（缓慢地，从容不迫地）
in two or three. If a draw is half made and then
stopped, it may be necessary to anneal（退火） before
proceeding, that is（换句话说）, if the piece is given
time to work-harden. This may not be a scientific
statement, but it is actually what seems to happen.
Internal stresses
Cold forming is done above the yield point in the
work-hardening range, so internal stresses can be
built up easily. Evidence of this is the springback
（回弹） as the work leaves the forming operation and
the warpage（翘曲，扭曲） in any（任何一种） subsequent
heat treatment. Even a simple washer might, by virtue
of[由于，凭借](依靠) the internal stresses resulting
from punching（冲压） and then flattening（整平）, warp
（弯曲） severely（严格地，激烈地） during heat
treating. （virtue n.德行, 美德, 贞操, 优点, 功效,
效力, 英勇 believed in the virtue of prayer.相信祈
祷的力量
When doubt exists as to（关于） whether internal
stresses will cause warpage, a piece can be checked
by heating it to about 1100 and then letting it cool.
If there are internal stresses, the piece is likely
to（可能） deform. Pieces that will warp severely while
being heated have been seen, yet （然而）the
heat-treater[热处理炉] was expected to[有望做某事；
被期待做某事] put them through[put through 完成] and
bring them out better than they were in the first
place.
Welding
The maximum carbon content of plain carbon steel safe
for welding without preheating or subsequent heat
treatment is 0.3%. higher-carbon steel is welded
every day, but only with proper preheating. There are
two important factors: the amount of heats that is put
in the rate at which it is removed.
Welding at a slower rate puts in more heat and heats
a large volume of metal, so the cooling rate due to
loss of heat to the base metal is decreased(减少). A
延展性，使其在没有断裂的情
况下成形。加工力的大小取决
于屈服点，因为钢在屈服点之
上才开始变形。与此同时，加
工硬化也同时发生，金属变得
越来越硬，增加加工难度，尤
其在低碳钢中容易发生。
在这方面，相当有趣的是你将
发现有时可通过一次快速加载
完成大拉伸，但以缓慢的方式
两三次加载却不能实现。如果
拉伸进行了一半就停止了，那
么在再加工之前应先退火，也
就是说工件是否有时间进行加
工硬化。这不是一种科学的叙
述方法，但确实是发生了。
内应力
在高于屈服点的加工硬化区进
行冷加工很容易产生内应力。
例如工件停止成型加工后会发生回弹，在随后的热处理后，
工件会发生翘曲。即使是一个
简单的垫圈，由于打孔和随后 的平整加工中产生内应力，也
会在热处理中呈现严重的翘
曲。
当是否内应力会引起翘曲的怀
疑存在时，可以通过将工件加
工至1100然后进行冷却来验
证。如果存在内应力，工件会
发生变形。经过热处理的工件
像我们看到的那样会发生严重
的翘曲，但是我们仍然希望工
件被扔到热处理炉中被处理，
这样好过它存在内应力的状
态。
焊接
不需要预热或之后进行热处理
就能安全焊接的最高碳含量为
0.3％。高碳钢通过合适的预热
通常也可焊接。有两点值得注
意：吸收热量的多少；移除速
度。
低速焊接带来了更多的热
量，这对金属的大量体积进行
了加热，所以冷却速度降低。
preheat will do the same thing. For example, sae4150
steel, preheated to 600 or 800, can be welded readily
（容易地）. When the flame or arc is taken away from
the weld, the cooling rate is not so great, owing to
the higher temperature of the surrounding metal and
slower cooling results. Even the most rapid
air- hardening（风硬钢） steels are weldable if
preheated and welded at a slow rate.
Machinability
Machinability（机械加工性能） means several things.
To production men it generally means being able to
remove metal at the fastest rate, leave the best
possible finish, and obtain the longest possible tool
life. Machinability applies to（应用于） the tool- work
（工具，零件） combination.
It is not determined by hardness（硬度） alone, but
by the toughness（韧性）, microstructure, chemical
composition（成分）, and tendency（倾向） of a metal
to harden under cold work. In the misleading
expression “too hard to machine”, the word “hard”
is usually meant to be synonymous（同义的） with
“difficult”. Many times a material is actually too
soft to machine readily. Softness and toughness may
cause the metal to tear（撕裂） and flow ahead of the
cutting tool rather than cut cleanly. Metal that are
inherently（天性地，固有地） soft and tough are
sometimes alloyed to improve their machinability at
some sacrifice[n. 牺牲；祭品；供奉.]（牺牲） in
ductility. Examples are use of lead（铅） in brass
（黄铜） and of sulfur[]（硫磺） in steel.
Machinability is a term used to indicate the relative
（比较的） ease（不费力） with which a material can
be machined by sharp cutting tools in operations such
as turning（车）, drilling（钻）, milling（铣）,
broaching[n. 拉削；拉孔；推削；扩孔v. 钻孔；开口]
（拉削）, and reaming（铰）.
In the machining of metal, the metal being cut, the
cutting tool, the coolant, the process and type of
machine tool（机床）, and the cutting conditions all
influence the results. By changing any one of these
factors, different results will be obtained. The
criterion[n. （批评判断的）标准；准则；规范；准据]
（标准） upon which the ratings（等级） listed are
based(等级评定的标准) is the relative[adj. 相对的；
有关系的；成比例的] volume of various（不同种）
materials that may be removed by turning under fixed
conditions to produce an arbitrary（任意的） fixed
amount of tool wear.
Unit3 Mechanical Properties of Materials
预热可以取得与之相当的效
果。例如当被预热至或
时可以很好的焊接。由于周围
金属的较高温度，当焊接弧移
开焊接点后，冷却速度不会太
快，产生了低速冷却的结果。
即使是冷作硬化速度最快的金
属也可以通过预热和慢速焊接
达到良好的焊接效果。
可加工性
可加工性意味着几件事情。对
于加工者来说，它意味着可以 快速的移除金属，取得最好的
加工效果，得到最长的刀具寿
命。可加工性是刀具和零件的
结合。
加工性不仅仅只由硬度决定，
它还由韧性，微观结构，化学
成分和在冷加工下金属所呈现
的硬化特性所决定。在容易混
淆的表示“难加工”中，“hard”
与“difficult”同义。许多时
候，因为材料过软而难于稳定
加工。材料柔软性和韧性能够
产生金属撕裂，使金属在完成
切削前流动至刀具前端。柔软
的金属往往会被加入合金从而
牺牲它的延展性来提高加工性
能。如黄铜中加入铅钢中加入
硫磺。
机械加工性能是在指对工件材
料使用刀具进行诸如车、钻、
铣、拉削、铰加工时的难易程
度。
在对金属进行加工时，被切削
的金属，切削刀具，冷却液，
使用的机床的种类，切削条件
均影响着切削效果。改变任何
一种均会产生不同的切削效
果。切削效果评定的准则是：
车削时在固定的切削条件下产
生一定量的刀具磨损时，被加
工试件相应的材料去除量。
The material properties can be classified into three
major headings: (i) Physical, (ii) Chemical, (iii)
Mechanical.
Physical properties
Density or specific gravity, moisture[n. 水分；
湿度；潮湿；降雨量] content, etc., can be classified
under this category.
Chemical properties
Many chemical properties come under[归入] this
category. These include acidity[n. 酸度；酸性；酸过
多；胃酸过多] or alkalinity[n. 碱度；碱性],
reactivity[化学反应的活性] and corrosion. The most
important of these is corrosion which can be explained
in layman’s terms as the resistance of the material
to decay[腐朽，腐烂] while in continuous use in a
particular atmosphere.
Mechanical properties
Mechanical properties include the strength
properties like tensile, compression, shear,
torsion, impact, fatigue and creep[n. 爬行；毛骨悚
然的感觉；谄媚者vi. 爬行；蔓延；慢慢地移动；起鸡皮
疙瘩creep:蠕变|潜变|渐变creep strength:蠕变强度|
潜变强度|蠕变弱度creep strain:蠕变变形|蠕动应变|蠕
变应变]. The tensile strength of a material is
obtained by dividing the maximum load, which the
specimen bears by the area of cross-section of the
specimen.
This is a curve plotted between the stress along
the Y-axis(ordinate) and the strain along the
X-axis(abscissa[n. [数]横坐标；横线]) in a tensile
test. A material tends to change or changes its
dimensions when it is loaded, depending upon the
magnitude[大小] of the load. When the load is removed
it can be seen that the deformation disappear s. For
many materials this occurs up to[一直到；相当于；忙
于，在做；由决定的] a certain value of the stress
called the elastic limit. This is depicted by the
straight line relationship and a small deviation[n.
偏差；误差；背离average deviation:平均偏差|平均差|
平均偏差，均差] thereafter, in the stress-strain
curve.
Within the elastic range, the limiting value of the
stress up to which the stress and strain are
proportional, is called the limit of proportionality.
In this region, the metal obeys Hooke’s law, which
states that the stress is proportional to strain in
the elastic range of loading (the material completely
regains its original dimensions after the load is
removed). In the actual plotting of the curve, the
proportionality limit is obtained at a slightly lower
材料特性主要分为三类：(i)物
理特性，(ii)化学特性，(iii)
力学性能。
物理特性
密度或特定的重力，湿度
等都属于此范畴。
化学特性
许多化学特性都归入到这
个范畴。其中包括酸性或碱性，
活性和耐腐蚀性。而在这其中
最重要的是耐腐蚀性，通俗的
解释是材料在特定大气中长期
使用时，抵抗腐蚀的能力。
力学特性
力学特性包括诸如拉伸，
压缩，剪切，扭转，冲击，疲
劳和蠕变等强度特性。一种材
料的拉伸强度由试件承载的最
大载荷除以试件的横截面积得
到。
如图所示为在拉伸试验中沿着
X轴（横轴）的应变和沿着Y轴
（纵轴）的应力之间的关系曲
线。材料在加载时，随着载荷
大小的变化，尺寸会发生改变。
当卸载时，变形消失。对于许
多材料来说，上述情况发生的
应力极限值称为弹性极限。在
应力- 应变曲线中，直线关系和
随后的小小的弯曲描述了上述
的加载和卸载。
在弹性范围内，应力应变成比
例的应力极限值称为比例极
限。在这个区域中，金属服从
胡克定律—阐述了在加载的弹
性范围内，应力和应变成比例
关系（材料在卸载后，能够完
全回复它原来的尺寸）。在曲线
的实际绘制中，比例极限值要
稍微比弹性极限值低。这可能
val ue of the load than the elastic limit. This may be
attributed to the time-lag in the regaining of the
original dimensions of the material. This effect is
very frequently noticed in some no- ferrous[有色金
属][铁的，含铁的] metals.
While iron and nickel exhibit[n. 展览品；证据；
展示会vt. 展览；显示；提出（证据等）vi. 展出；开展
览会] clear ranges of elasticity, copper, zinc（锌）,
tin（锡）, etc, are found to be imperfectlyadv. 有
缺点地；不完美地；未完成地] elastic even at relatively
（相当地） low values of stresses. Actually the
elastic limit is distinguishable（可区分的） from the
proportionality（比例性） limit more clearly
depending upon the sensitivity（灵敏性） of the
measuring instrument.
When the load is increased beyond the elastic
limit, plastic deformation starts. Simultaneously
the specimen gets work-hardened. A point is reached
when（这时） the deformation starts to occur more
rapidly than the increasing load. This point is called
the yield point Q. the metal which was resisting the
load till then, starts to deform somewhat rapidly, i.
e. , yield. The yield stress is called yield limit.
The elongation of the specimen continues form Q
to S and then to T. the stess-strain relation in this
plastic flow period is indicated by the portion QRST
of the curve. At T the specimen breaks, and this load
is called the breaking load. The value of the maximum
load S divided by the original cross-sectional area
of the specimen is referred to as the ultimate tensile
strength of the metal or simply the tensile strength.
Logically speaking, once the elastic limit is
exceeded, the metal should starts to yield, and
finally break, without any increase in the value of
stress. But the curve records an increased stress even
after the elastic limit is exceeded. Two reasons can
be given for this behavior:
1， the strain hardening of the material;
2， the diminishing[adj. 逐渐缩小的；衰减的v. 减少；
递减；衰减；削弱的权势] cross-sectional area of
the specimen, suffered on account of [On account
of the weather, we had to cancel the projected
outing.]the plastic deformation.
The more plastic deformation the metal undergoes,
the harder it becomes, due to work- hardening. The more
the metal gets elongated the more its diameter(and
hence, cross- sectional area) is decreased. This
continues until the point S is reached.
After S, the rate at which the redution in area takes
是由于材料回复原尺寸需要的
时间延迟。这种现象在一些有
色金属中常常出现。铁和镍存在明显的弹性范围，
铜，锌，锡等即使在相当低的
应力值下弹性也表现得不是很 充分。实际上依靠测试仪器的
精确性可以使比例极限和弹性
极限区分得更清晰。
当在弹性极限之上增大载荷时
会产生塑性变形。同时，试件
发生加工硬化。到达某点后变形的速度快于载荷增加的速
度。这一点叫做屈服极限点。
一开始一直在抵抗载荷的金属在这一点后开始迅速地发生形
变，也就是，屈服。屈服应力
叫做屈服极限。
试件从Q到S在到T不断地延
长。在这个塑性流动期间的应
力-应变关系表示为曲线上的
Q RST段。在T点试件断裂，此
时的载荷称为断裂载荷。最大
荷载值S除以试件的横截面积为金属的最大拉伸强度或简单
地称为拉伸强度。
逻辑上来说，一旦超过弹性极
限，金属应该就会屈服直至最
后断裂，在应力值上应该没有
增加。但是实际的曲线却记录
了在超过弹性极限后的增加了
的应力。这种现象的发生可能
有两种原因：
1材料的应变强化；
2由于塑性变形引起的试件横
截面积的缩小。
由于加工硬化，金属在发生塑
性变形时会变得越来越硬。金
属拉伸越长它的直径越小。这
种现象一直持续到曲线上的S
点。
超过S点后，面积减少的速度
place, exceeds the rate at which the stress increases.
Strain becomes so high that the redution in area
begins to produce a localized effect at some point.
This is called neching.
Reduction in cross-sectional area takes place
very rapidly; so rapidly that the load value actully
drops. This is indicated by ST. Failure occurs at this
point T.
Then percentage elongation and reduction in area
indicate the ductility or plasticity of the material:
Where and are the original and the final length of the
specimen; and are the original and the final
cross-sectional area.
Unit6 Manufacture Process(1)
Computer- Aided Manufacturing
The scientific study of metal-cutting and
automation techniques is products of ,he iw.-n tieth
century. Two pioneers of these techniques were
Frederick Taylor and Henry Ford. During the early
1900s, the improving U. S. standard of living brought
a new high m pervxi- al wealth. The major result was
the increased demand for durable goods. This
increased demand meant that manufacturing could no
longer be treated as a blacksmith trade, and the use
of scientific study was employed in manufacturing
analysis. Taylor pioneered studies in
management
men and machines were studied. Taylor also conducted
metal cutting experiments at the Midvale Steel
Company that lasted 26 years and produced 400 tons of
metal chips. The result of Taylor's metal-cutting
experiments was the development of the Taylor
tool-life equation that is still used in industry
today. This tool-life equation is still the basis of
determining economic metal cutting and has been used
in adaptive controlled machining.
超过了应力增加的速度。应变变得很大，面积的减少在某些
点产生了局部效应。叫做颈缩。
横截面积减小的速度非常快；
以至于实际上载荷降低。
伸长率和面积减少率表示
了材料的延展性。
Henry Ford's contributions took a different turn from
Taylor's. Ford refined and devel-oped the use of
assembly lines for the major component manufacturer
of his automobile. Ford felt that every American
family should have an automobile, and if they could
be manufac-tured inexpensively enough then every
family would buy one. Several mechanisms were
developed at Ford to accommodate assembly lines. The
automation that Ford developed was built into the
hardware, and Ford realized that significant demand
was necessary to offset the initial development and
production costs of such systems.
计算机辅助制造
对金属切削和自动化技术的科
学研究时二十世纪的产物。泰
勒和亨利是这些技术的先驱。
1900年代早期，美国日益提高
的生活水平将个人财富带到了
一个新的高度。这种现象主要
影响就是对耐用品德需求的增
长。日益增长的需求意味着制
造业不再是简单的手工作坊式
的行业，而应该在制造业中引入科学化的研究手段。泰勒开
创性的对“科学管理”进行的
研究，研究对象包括用手工和 机器两种生产方式的方法。泰
勒还领导了在费城穆德维尔钢
铁公式进行的金属切削实验，
该实验持续了26年，产生了400
吨金属切削，近视切削实验最
后得到了工业上至今还在使用
的泰勒刀具寿命公式。
该道具寿命公式仍然是决定金
属切削经济性的依据，他还被
应用于自适应控制机床中。
亨利福特的贡献与泰勒的不
同。福特改进和发展了为他的
汽车生产主要零部件的装配线
（的应用）。福特认为每个美国
家庭都应该有一部汽车，如果
生产出来的汽车足够便宜那么
每个美国家庭都会买一部。福
特工厂制造了一些机械装置以
适应装配线。福特使用的制动
化时集成于硬件中的，他意识
到了为了弥补系统的早期开发
和制造成本必须有非常大的产
Although manufacturing industries continued to
evolve, it was not until the 1950s that the next major
development occurred. For some time, strides to
reduce human involvement in manufacturing were being
taken. Specialty machines using cams and other
logic controllers had been developed. The
U. S. Air Force recognized the development time
required to produce this special equipment and that
the time required to make only small sequence changes
was excessive. As a result, the Air Force commissioned
the Massachusetts Institute of Technology to
demonstrate programmable or numerically controlled
(NC) machines (also known as
With this first demonstration in 1952 came the
beginning of a new era in manufacturing. Since then,
digital computers have been used to produce input
either in a directed manner to many NG machines，direct
numerical control (DNC)，or in a more dedicated
control sense, computer numerical control (CNC).
Today, machine control languages such as APT
(Automatic Programming Tool) have become the standard
for creating tool control for NC machines.
It is interesting to note that much of the evolution
in manufacturing has come as a response to particular
changes during different periods. For instance, the
technology that evolves in the nineteenth century
brought with it the need for higher- precision
machining.(This resulted in the creation of many new
machine tools, a more refined machine design,诵 and
new production processes. ) The early twentieth
century became an era of prosperity and 1
industrialization that created the demand necessary
for mass-production techniques. In the ：^ 1950s it
was estimated that as the speed of an aircraft
increased, the cost of manufacturing ！ the aircraft
( because of geometric complexity) increased
proportionately with the speed- The | result of this
was the development of NC technology.
A few tangential notes on this history include the
following. As the volume of parts I manufactured
increases, the production cost for the parts decrease
(this is generally known | as “economy of scale”）.
Some of the change in production cost is due to fixed
versus variable 1 costs. For instance，if only a single
part is to be produced (such as a space vehicle) , all
of 1 the fixed costs for planning and design (both
product and process) must be absorbed by the | single
item. If, however, several parts are produced，the
fixed charge can be distributed over 1 several parts.
品需求。
制造业持续发展，但直到20实
际50年代才出项了下一个重要
的突破。长期以来，人们一直
致力于减少制造过程中的人为
参与。那是已经开发出了使用
凸轮和其他“硬布线”逻辑控
制器的专用机床。美国空军意
识到此类专门设备的开发时间
和对设备的工做顺序进行微小
改动所学的时间过长。因此，
美国空军委托麻省理工学院来开发一种可编程的或者数字化
的控制的机器（也称为“软布
线”机械）。制造业的新纪元从
1952年的这次首创开始了。从
此以后，电子计算机被用来进
行数据输入，或者以直接的方
式用在去多NC机床上(DNC)，
或者以更专业的方式用在计算
机数控机床上（CNC）。
有意思的时制造业的许多发张
都对应与不同历史时期的特殊
变化。例如，19世纪工业技术
的发展带来了对高精密加工的
需求。（因而产生了许多新型的
机床，更精细化的机械设计和
新的生产工艺。）20世纪初期成
为繁荣的工业化时代带来了对
大规模生产技术的需求。20世
纪50年代，人们认为随着飞机
飞行速度的增加，飞机的制造
成本也成比例的增加（由于几
何结构的复杂性），正是这个原
因导致了NC技术的发展。
关于这段历史的还有下面一些
值得关注的地方。随着零件生
产数量的增加，零件的生产成
本降低（这就是众所周知的规
模经济）。生产成本变化部分的
时由于固定成本对可变成本比
例的变化。例如，如果仅仅生
产单独一个零件（例如太空飞
行器），所有用于计划，设计（包
括产品和工艺两方面）的固定
成本都要集中在这一个零件
Chang es in production cost，not reflected in this
simple fixed-versus variable- | cost relationship，
are usually the result of different manufacturing
procedures—transfer- line techniques for
high-volume items versus job-shop procedures for
low-volume items①.
Automated Manufacturing Systems
An automated manufacturing system consists of a
collection of automatic or semiauto- 1 matic machines
linked together by a “intrasystem”
material-handling system- These systems have been
around since before Henry Ford began to manufacture
his Model T on his moving j assembly line. These
automated systems have been used to produce machined
components， assemblies, electrical components, food
products, chemical prod”—° …一techniques tor
high-volume items versus job-shop procedures for
low-volume items^. Automated Manufacturing SystemsAn
automated manufacturing system consists of a
collection of automatic or semiauto-matic machines
linked together by a “intrasystem”
material-handling system. These systems have been
around since before Henry Ford began to manufacture
his Model T on his moving assembly line. These
automated systems have been used to produce machined
components, assemblies, electrical components, food
products, chemical products, etc. The total number of
products produced on a single system varies with the
production methods. However, the principles of
designing the production systems are the same
independently of the product being manufactured. The
workstations in a production system can be manual，
semiautomatic or fully automatic. The automatic
stations can be programmable or hardwired.
The purpose of any production system is to produce a 任何生产系统的目的都是为了
product or family of products in { the most economical 以最经济的方式生产一种或一
manner. Automated production systems are no different 系列产品。自动化生产系统与
from any other j type of manufacturing system. In 其他的制造系统没有区别。自
order to employ any form of automation，the 动化的任何实现方式在经济性
implementa- 1 tion must be economically justifiable. 上必须是合理的。自动化通常
Automation has traditionally b厶en most appropriate 适用于高附加值产品。然而，
for high-value products. However, flexible 柔性自动化装备也应用于一些
automation equipment has brought automation to some 低价值产品的生产。
relatively low value products.
Unit7 Shapers, Planers, Milling and Grinding Machines
Shapers 刨床
Shapers are machine tools used primarily in the 刨床是主要用于加工平面和斜
上。如果该零件生产了多个，
固定支出就能够被分摊到多个
零件上。不能用上述简单的固
定成本——可变成本的关系进
行解释的生产成本的变化通常
是采用不同制造方法的结果—
—————自动成产线用于大
批量生产，加工车间用于小批
量生产。
自动化制造系统
自动化制造系统由一系列的自
动化机床或半自动化机床，及
将他们连接到一起的内部物料
传送系统组成。这种系
统从亨利福特在他的移动装配
线上生产他的T型汽车之前就
已经得到了应用。这些
自动化系统被用来生产机器零
部件，装配件，电器元件，食
品，化工产品等。一套
系统生产的产品总量随着生产
方法的不同而不同。在
一个系统内生产的数量随着加
工方法的不同而不同。
然而，不管生产的产品是什么，
设计生产系统的原理是一样
的。再生产系统中的工
作站可以是手工的，也可以式
半自动的或者全自动的。
全自动的工作站可以是可编程
的也可以是硬布线的。
production of flat and angular surfaces. In addition,
the shaper is used to machine irregular shapes and
contours which are difficult to produce on other
machine tools. Internal as well as external surfaces
and shapes can be pro-duced on the shaper. Common
shapes produced on the shaper are flat，angular,
grooves, dovetails，T-slots, key ways, slots,
serrations, and contours. Single-point cutting tools
sim-ilar to the type used on the lathe are used in
machining most surfaces on the shaper. Contour
surfaces can be produced with either a single-point
tool or a formed cutting tool. When using a
single-point cutting tool for contour surfaces, the
depth of cut must be constantly regulated by the
machine operator to achieve the proper contour
①.Profiling attachments can be used on some shapers
to regulate the feed motion and provide duplication
of other parts. Numeri-cal control units also enable
the production of irregular surfaces with constant
regulation of the depth of cut.
Shapers are classified by the plane in which the
cutting action occurs, either horizontal or vertical.
In addition the horizontal-type shapers are further
classified as push or pull cut. A push-cut shaper cuts
while the ram is pushing the tool across the work, and
a pull cut ma-chine removes material while the tool
is pulled toward the machine②.Vertical shapers use
a pushing-type cutting action and are sometimes
referred to as slotters or keyseaters.
Planers
Planers are similar to shapers because both machines
are primarily used to produce flat and angular
surfaces. However, planers are capable of
accommodating much larger work- pieces than the
shaper. In planer operations the workpiece is mounted
on the table which re-ciprocates in a horizontal plane
providing a straight-line cutting and feed action.
Single-point cutting tools are mounted on an overhead
cross rail and along the vertically supported
col-umns. The cutting tools are fed into or away from
the workpiece on either the horizontal or vertical
plane, thus being capable of four straight-line feed
motions.
Cutting speeds are slow on the planer because of the
workpiece size and type of cutting tool being used.
In order to increase the production of the planer,
multiple tooling stations are employed. Two tooling
stations are located on the overhead cross rails, with
usually one tooling station on the vertical supports.
Another method of increasing production on the planer
面的机床。此外，刨床还可以
用于加工在其他机床上难以加
工的不规则形状的轮廓（如内
花键，齿轮）。内外表面和形状
都可以在刨床上加工。刨床还
可以加工的形状通常有平面，
斜面，沟槽，燕尾槽，t型槽键
槽，窄槽，锯齿和外形轮廓。
刨床加工大多数形状时使用与
车窗刀具类似的单点切削刀
具。轮廓面可以单点切削刀具
加工，也可以用成型刀具加工。
用单点切削刀具加工轮廓面
时，操作人员必须不停的调整
切削深度以加工出合适的轮
廓。在一些抱床上可以用方形
附件调整进给运动，复制其他
零件（的轮廓）。使用数字控制
单元连续第调整切削深度也可
以实现不规则表面的加工。
按照其切削运动所处的平面，
刨床可分为立式刨床和卧室刨
床。卧室刨床还可以进一步分
为=推刨和拉刨。推刨是指滑枕
推动刀具向工件方向运动时进
行切削，拉刨是指刀具被拉向
机床方向时切除金属，采用推
刨的方式的立式刨床又是被称
为插床或键槽插床。
龙门刨床
龙门刨床于刨床类似，因为两
者都主要用来加工平面或斜
面。但龙门刨床适合加工尺寸
更大的工件。在龙门刨床的加
工过程中，工件安装在工作台
上，工作台在水平面内往复运
动，提供直线切削和进给运动。
单点切削刀具安装在上方的交
叉导轨上，延立柱方向垂直安
装。刀具在追平面和垂直面内
都可以朝向工件或远离工件做
进给运动，因此刀具具有四个
直线进给运动。
因为工件尺寸和使用刀具类型
的关系，龙门刨床的切削速度
比较慢。为了提高龙门刨床的
生产效率可采用多个刀架同时
切削。通常在上方导轨上会安
装两个刀架，在垂直导轨上会
安装一个。另一种提高龙门刨
is to mount a number of workpieces on the table at the
same time. This method is on-ly feasible when the
workpieces require the same cut and are relatively
small in size. The planer size is designated by the
maximum workpiece capacity of the machine. The
height. width, and length of the workpiece that can
be accommodated on the planer's worktable va-ries
with the type of planer.
Milling Machines
Milling machines are probably the most versatile
machine tools used in modern manufac-J
turing with the exception of the lathe. Primarily
designed to produce flat and angular sur-Tfaces, the
milling machine is also used to machine irregular
shapes，surfaces, grooves, and ]slots. The milling
machine can also be used for drilling, boring,
reaming，and gear-cutting 1operations.
A number of different types of milling machines are
manufactured in order to serve the ]multitude of needs
and the diverse applications. Milling machines are 琴
sified according totheir structure and include
column-knee, fixed bed, planer, and special machines.
Grinding Machines
Grinding machines utilize abrasive grains，bonded
into various shapes and sizes ofwheels and belts to
be used as the cutting agent. Grinding operations are
used to impart ahigh-quality surface finish on the
workpiece. In addition, the dimensional accuracy of
theworkpiece is improved since tolerances of 0. 00001
in. [0. 00025mm] are possible in grindingoperations.
Both internal and external surfaces can be ground by
using the variety of grindingmachines available.
Related operations~ which use abrasives in various
forms such as past^，powder, and grains—include
lapping, honing, and drum finishing.
生产率的方法是在工作台上同
时装夹多个零件，这种方法只
有在工件加工内容相同且尺寸
较小时才能采用。龙门刨的规
格是由机床所能加工零件的最
大尺寸决定的。龙门刨型号不
同，其工作台上能够安装的零
件长，宽，高也不同。
铣床
铣床可能是现代制造业中除了 车床外应用最广一种机床，铣
床主要涉及用于加工平面和斜
面，也可以用来加工不规则形
状，曲面，沟槽，窄槽。铣床
还可以进行钻，镗，铰和齿轮
加工。
大量不同种类的铣床被制造出
来以适应于各种不同的需求和
应用场合。铣床通过其结构来
定义其类型，包括柱膝式，固
定工作台式，龙门式和专用铣
床。
磨床
磨床使用磨粒进行切削，磨粒
粘接在一起形成各种形状和尺
寸的砂轮和砂带（供磨床使
用）。磨削可以带来高质量的工
件表面。工件的尺寸精度也可
以提高，因为磨削加工的公差
可以达到0.00025mm。现有的各
类磨床可以加工工件的内外表
面。与磨床有关的其他加工方 法还包括研磨，和抛光（布，
橡胶，木鼓轮）————需要
使用不同形式的研磨剂诸如糊
状，粉状和粒状。
Grinding machines are classified according to the 磨床按照加工表面类型来分
type of surface produced. Common surfacesand 类。常见的平面磨，内外圆磨，
classifications of grinding machines are surface ’ 和专用磨床等。
cylindrical，and special machines.
Unit 9 NC Machines
Machine may be classified according to the number 机器根据多轴数控运动方面笛
of axes of numericallycontrolled movements with 卡尔某某坐标可分为多种。有
respect to Cartesian X-Y-Zcoordinates. There may be 可能是其他运动的数字控制。
other movement not numerically controlled. A 一种双轴机将表的纵向和横向
two-axis machine would have the table movedlengthwise 移动在水平面三轴机将有额
and crosswise in a horizontal plane; athree-axis 外的主轴垂直运动例如四
machine would have an additional vertical movement of -五-或提供额外的线性轴
the spindle,for example, Four-, five-, or six-axis 机或旋转运动。
machines provide additional linear or rotary
movements.
Three classes of NC systems are commonly recognized. 在三类数控系统中。其中一类
One of these iscalled point-to- point or positioning 被称为逐点或位置调节数控
NC, where a cuttingtool and workpiece are positioned 在这类数控系统中进行切削
with respect to each other before a cut is taken, 之前切削刀具和工件彼此之
asexemplified by an NC drill press~. The path between 间的位置就被确定了数控钻
points is of little concern and is notparticularly 床就是一个例子。点之间的路
controlled. Another class,known as a straight-cut 径不太重要不是特别控制。
NC system, involves movementsbetween points like 另一类称为数控纵切系统
point- to-point NC but along straight or curved paths 涉及运动点像点位数控但沿直
determined by themachine ways or slides. An NC turret 线或曲线路径决定的方式或过
lathe may beof the second class. A third class is 程。数控转塔车床可能是二类。
continuous-path NC, or more formallycontinuous tool 三分之一类是连续轨迹数控
pathcontrol, which does contouring or profiling of 或更正式的连续轨迹控制其
lines, curves, or surfaces, ofall shapes. Oneway of 轮廓或轮廓线曲线或表面
achieving continuous path NC is to move the workpiece 各种形状。得到数控连续路
or cutter frompoint to point along a straight line 径的一种方式是使工件或刀具
or curve (aparabolic path between points is used on 沿一直线或曲线做点到点的运
some machines) with many points spacedclosely enough 动在某些机床上点之间采
together so that the composition path of the 用抛物线路径许多点的间隔
cutapproximates a desired curve within limits 足够小一边在要求的限度内
required~. Another way is to drivemachine members, 使切削组合的路径接近一预想
say a saddle and the table on it,along coordinate axes 的曲线。。另一种方法是驱动机
at varying velocities controlled so that the 器的成员说一个鞍状结构
resultantmotion is along a particular line or curve. 沿坐标轴以不同的速度控制
由此产生的运动是在一个特定
的直线或曲线。
An NC machine may be controlled through an open-loop 数控机床可控制通过一个开环
or closed-loopcircuit as depicted in Fig. 9.1. The 或闭环电路如图9.1所。开环
open-loop system is the simplest andcheapest but does 系统是最简单和便宜但不保证
not assure accuracy. A signal that is an order for a 准确性。一个信号,表明是一个
certainaction (such as to turn on the coolant, start 为了一个特定操作(例如打开
the spindle, or move the table toa certain position) 冷却剂,启动主轴,或的表移动
is issued by the control unit. This travels through 到某一个位置)发出控制单元。
thedrive mechanism which imposes the action upon the 这个过程,通过驱动机制规定
controlled member of the basic drive 行为控制机器的成员。在开口
mechanism for a table or other machine member in an 回路系统中一工作台或其他
open- loop systemis a stepping motor, also called a 机器构件的基本的驱动机制是
digital or pulse motor. It has, for example,49 poles 步进电动机,也称为数字或
around the armature inside of 50 poles around the 脉冲发动机。比如,它在电枢内
stator. Two poles are always aligned. Poles 部49波兰人在定子的50波兰
areenergized to align the next two poles and turn the 人。两个极点总是一致的。波
armature through a definitesmall angle each time a 兰人有足够的精力来调整下两
pulse of electricity is received. The motor turns 个极点,将通过一个明确的小
theleadscrew, which moves the table a corresponding 角度电枢每次收到的脉冲电。
distance. If, for example, a pulse stands for a 马达转动的有,移动表对应的
0.001mm movement, and a movement of 0.05 mm is 距离。比如说,如果一个脉冲代
desired, the control unit issues50 pulses; the motor 表一个0。001毫米的运动,和
turns through 50 steps and turns the leadscrew, and 一个运动的0.05毫米是很明显
thetable (or other member) is driven the 0.05 mm 的控制单元50脉冲;马达
required. The rate at which the pulsesare issued
determines the rate of feed. The power of a stepping
motor islimited, and if the resistance to movement is
large, the motor may just stalland miss steps. There
is no feedback to report the omission, and accuracy
islost. Direct drive with a stepping motor is confined
to light service atfractional horsepower. For more
power and heavy service, a stepping motor ismatched
with a hydraulic motor through a servo valve for table
drives up to7.5kW (10 hp) and more.
It is common inclosed-loop systems for the pulsed
command signal for the movement of the table(or other
member) of the machine to be converted to a steady
analog signal turns on the power to the
drive mechanism. Hydraulic and ac but mostly dc
electric motorsare all used for NC machine drives. The
intensity of the signal is determinedby the feed
velocity ordered. For a higher feed, pulses are issued
at a fasterrate andor the analog signal is larger,
which turns on more power to the motorto drive the
table faster. A tachometer in the motor drive sends
back a signalthat is compared to the feed rate order
to assure that the required feed rateis being
delivered and to make corrections if it is not.
Commonly, a resolveris driven by the leadscrew and
returns a signal showing how far the tablemoves. More
accuracy for a longer period of time is obtained with
the feedbackdevice attached directly to the table,
but such devices are more costly. Thefeedback signal
is compared to the order, and where the feedback
equals theorder and signifies the required movement
has been completed, the power is shutoff, and the
movement stops. Since they are controlled through
separatechannels, all movements may act at the same
time. Indeed, it is necessary thatthey act
simultaneously and be synchronized accurately for
contouring.
Unit 10 Hydraulic System
液压系统
一、New words and expressions
二、Translation
Hydraulic System
液压系统
1、The history of hydraulic power is a long one, dating from man’s prehistoric efforts
to harness the energy in the world around him. 水力的历史由来已久，它始于人类史前的为
利用其周围的能源而做出努力。history 历史 power 动力 dating from…源于…，追溯回…
prehistoric 史前 effort 功夫工夫成就 harness 利用驾驭治理
转动到50步和将有和表( 或其
他)是0.05毫米驱动所需的。
脉冲的速率决定的速度进给。
步进电机的力量是有限的,如
果抵抗运动是大型汽车可能只
是停滞,错过的步骤。没有反馈
报告遗漏,和失去了准确性。与
步进电机直接驱动仅限于光服
务在分马力。更多的力和沉重
的服务, 一个步进电机配个通
过伺服阀液压马达为表驱动
7.5千瓦(10点)和更多。
这是常见的闭环系统的脉冲信
号指挥运动或其他的机器
转换到一个稳定的模拟信号。
信号打开电源的驱动机制。液
压但大多都是采用直流电机驱
动的数控机床。发出脉冲的频
率确定进给的频率。一个较高
的进给脉冲发出以更快的速度
和或模拟信号较大这将在更
大功率电机驱动表更快。转速
的电机驱动发送信号假如不是
相对于进给率为保证所需的进
给和交付的配合。通常一个解
析器是由丝杠和返回信号显示
多长久表达动作。更准确的更
长的时间是反馈装置直接连接
到表，但这种装置是更昂贵。
反馈信号是相对于顺序并在反
馈等于输入意味着所需的运动
已经完成在电源关闭并停止移
动。因为他们是通过控制不同的渠道所有的运动可在同一时
间。事实上这是必要的他们的
行为的同时同步准确的轮廓。
The only sources readily available were the water and the wind——two free and moving
stream s.那时，易于得到且可供利用的仅有资源就是水和风——两种免费和运动的流体，水流和气
流。 source 来源源头根源 readily 容易爽快乐于 available 可用的 streams 流溪流
河流流水喷射
2、The watermill, the first hydraulic motor, was an early invention. 水磨，最早的水力
发动机，就是一种早期发明。 watermill 水磨水车 motor 马达发动机 invention 发明发
现
One is pictured on a mosaic at the Great Palace in Byzantium, dating from the early fifth
century. 有一幅画，以马赛克的形式被精雕在拜占庭的神殿内，其源于5世纪早期。mosaic 镶
嵌拼花的马塞克 Palace 宫殿 Great Palace 大宫殿 Summer Palace 颐和园 Byzantium 拜占
庭，古罗马城市
The mill had been built by the Romans. 画中的水车由古罗马人制造。
But the first record of a watermill goes back even further, to around 100 BC, and the
origins may indeed have been much earlier. 但关于水车的首次记录可以追溯到更早时期的大
约公元前100年左右，而实际出现还可能会更早。BC—Before Christ 公元前 Christ 救世主，基
督 origins 起源 indeed 确实的确
The domestication of grain began some 5000 years before and some enterprising farmer
is bound to have become tired of pounding or grinding the grain by hand. 谷物的人工种
植大约始于5000年以前，而从业农民肯定会疲于舂米和磨面的手工操作。 domesticate 驯养
domestication 驯化 grain 谷物= corn enterprising
a.
有事业心的;富进取心的;有魄力的
enterprise
n.
事业，进取心 bound 边界范围 be bound to 肯定，注定；一定会…，必然 tire
累疲倦 pound
v.
捣碎，猛击，敲打
n.
磅（1磅=0.454kg） grind
v. n.
磨碾
Perhaps, in fact, the inventor was some farmer’s wife, since she often drew the heavy
jobs. 事实上，水车的发明者也许是某个农夫的妻子，因为她们常常从事重体力劳动。 invent
v.
发明 inventor
n.
发明者 draw
v.
划画绘制描写拉拖拉长拖长拔提取 deep cold
drawing深度冷拔
3、Many mills stayed in use until the end of the 19th century, but they had been in the
process of being replaced by the steam engine as a source of power for the previous 150
years. 尽管很多水车直到十九世纪末仍在应用，但是，近150年来，以蒸汽机作为动力后，它们
就一直处于被替代的进程中。 stay
v.
留下逗留待停 process
n.
过程进程加工
v.
处理提
炼 steam
n.
蒸汽,水蒸汽气流 steam engine 蒸汽发动机 source
n.
源来源源头根源
previous
a.
以前过去
The transmission of the power generated by the waterwheels was by shafting and crude
gears or pulleys. 由水轮产生的动力通过传动轴、原始的齿轮或带轮来传递。 transmission
n.
传送，传播；传动装置，变速器 transformer
n.
变压器 generate
vt.
产生，发生；造成，引起；
生育，生殖 generator 发生器发电机 shaft
n.
轴
v.
安装配上 crude
a.
粗糙未加工天然的
粗野
n.
原油 gear
n.
齿轮 pulley
n.
皮带轮滑轮
The steam engine for the first time employed an enclosed moving stream of fluid (steam)
under pressure — the principle to be later employed in hydraulic power transmission —
for transmitting power continuously from the point of generation to the place where it
was used. 蒸汽机首次利用了在压力下的封闭的运动流体（或气流） — 该原理后来被用于液压传
动 — 压力下的运动流体被用来连续不断地把动力从源点传送到使用点。 employ
v.
采用雇佣
使用聘用 enclose
vt.
围住圈起关闭住封入
4、The transmission of hydrostatic power to a distant point began long before that, however.
但是，静液压远距离动力传送，早在此前就已开始了。 hydrostatic 静水静液压流体静力
hydrostatic power 静液压传动系统的能量 distant
a.
遥远远端离
Hero of Alexandria, in the first century AD, built a device in which a fire on the temple
altar expanded air in a closed container. 早在公元1世纪，即亚历山大时期的希罗就制造了
一种装置，该装置是用神坊之火加热一个密闭容器里的空气使之膨胀。 Hero希罗, 亚历山大时
期, 亚历山大城的机械师。 Alexandria亚历山大，古希腊文化鼎盛时期，也是当时的世界文化
中心之一。现为埃及北部港市。 AD——Anno Domini（拉丁语）公元 device 设备装置 temple
寺庙 altar 祭坛 expand 膨胀扩张扩大 closed container 密封容器。
The air pressure forced water to travel along a tube to the temple doors where, spilling
into a container, it provided the force through ropes and pulleys to magically open the
doors．空气的压力推动水通过一个管子到达庙门，在庙门，水流进一个容器，这个容器提供动力
并通过绳索和带轮神奇地把门打开。 pressure
n.
压力 force
n.v.
力动力强制 tube
n.
管子
桶 spill
v.
溢出溅出倾倒出 provide
v.
提供供应 rope
n.
绳子 pulley
n.
皮带轮
magically
adv.
不可思议地，有魔法地，神奇地
5、Hero also produced a steam engine of sorts.希罗还制造了一台类似的蒸汽机。sort
n.
类分
类种类
Its motion depended on the reaction forces from jets of steam, as in the present steam
turbine, but it was little understood and it was no more than an interesting curiosity.
如同当今的蒸汽轮机一样，依靠蒸汽的喷射作用力而产生运动，但人们对它理解甚少，对他的奇特
也失去了兴趣。 motion
n.
议案运动动作动力 depend on 依靠取决于依赖 reaction
n.
反应应对 reaction force 作用力 jet
v.
喷出射出
n.
喷嘴喷出物喷射器
a.
黑玉的乌黑发
亮的喷气推进的 turbine
n.
涡轮机汽轮机叶轮机 curiosity
n.
好奇心珍品奇珍奇特性
6、The invention of early forms of the hydraulic pump has a similarly early origin. 早
期形式的水泵的发明与水车应在同一时期。 invention
n.
发明发现 hydraulic
a.
水利的液压
的 hydraulic pump 液压泵 origin
n.
起源来源根源
The first pumps were not used to develop hydraulic power, however, but only to transfer
water for irrigation or to remove it from mines. 最早的水泵并非用于产生液压动力，而仅
仅是用于灌溉或抽出矿井中的水。 irrigation n.灌溉 mine
n.
我的矿山矿井地雷水雷坑
道
7、Archimedes applied the principle of the screw to hydraulic machines in the third century
BC. 早在公元前3世纪阿基米德就把螺杆原理应用到水力机械中。 principle
n.
原则原理道
理 screw
v.
拧紧
n.
螺旋螺丝钉
His screw pumps were used to raise water for irrigation or to the level of aqueducts.
他的螺旋泵用于提水灌溉或把水提升到引水渡槽的高度。 irrigation
n.
灌溉 aqueduct
n.
水道
沟渠
The piston pump, the first mechanical device capable of generating pressure in a column
of liquid, is believed to have come from Egypt at a similarly early date. 柱塞泵是历史
上第一台能使液压缸筒内产生压力的机械装置，人们认为它源于埃及，并与螺旋泵有同样悠久的历
史。piston
n.
活塞 device
n.
设备装置 mechanical device 机械装置 capable
a.
能力能干
有资格 generate
v.
生产产生发生 pressure
n.
压力 column
n.
圆柱，圆柱状物；（报纸、杂
志的）专栏，段 liquid
n.
液体
Like the screw pump, it was used only as a means for moving water and not as a means
for generating hydraulic power. 同螺旋泵一样，它只是被用来作为一种移水工具，而不是作为
一个产生液压力的手段。 means
n.
手段方法工具（mean
v.
意味着）
8、In more recent years, the role of leadership in hydraulic power application has been
taken over largely by some of the larger earthmoving and construction equipment
manufacturers. 近年来，一些规模较大的土建设备生产制造商在液压动力应用方面占有主导地位。
role
n.
角色任务 leadership
n.
领导，领导地位；领导才能 take over接管取代 earthmoving
土方工程 construction
n.
施工
The total power involved is often greater than that required in even the largest aircraft
systems. 动力总值通常总是稍大于所需的动力值，即使在最大型的航空器系统中也是如此。
involve
v.
涉及包含包括连累
The concentration of this power in a few very large loads, as compared to the multitude
of smaller loads in an airplane, has spurred the system designer to find new, creative
ways to distribute and control the power. 在一架飞机上，与多个小载荷相比，少数几个较
大载荷的动力集中的要求更能刺激系统的设计者去发现新的、创造性的方法去分配和控制动力。
concentration
n.
浓度专心精选集中 compare
v.
比较相比 as compared to 相比于
multitude
n.
多数 spur带动驱动刺激 distribute
v.
分配分布散布发布分发
This he has succeeded in doing to obtain maximum precision of control and productivity
while minimizing power consumption. 设计者在以最小的动力消耗去获得最精确的控制和最高
的效率方面，已经很成功了。 precision
n.
精确缜密 productivity
n.
产量生产率
minimizing 最大限度的减小 consumption
n.
消费消耗量
9、In modern mobile and industrial applications, the system designer has made full use
of the wonderful flexibility and adaptability of hydraulics. 系统设计者已经完美的将液
压技术灵活贴切的全面用于现代汽车和工业实际中。 application
n.
应用运用采用
flexibility
n.
灵活性挠性机动性 adaptability
n.
适应性 hydraulics
n.
水力学水利液压
It can readily be directed around corners and past involving joints that virtually defy
mechanical power transmission. 液压传动可以很容易地转过弯角，实现动力传递。而这种传动
是机械动力传输根本无法实现的。 readily
ad.
容易爽快乐意 direct
a.
直接
v.
指导指挥导
演指令主持 around
ad.p.
周围 corner
n.
角落 past
n.a.
过去
ad.
通过 involve
v.
涉及包
含牵涉 joint
n.v.
关节联接联合 virtually
ad.
实质上简直 defy
v.
藐视抗拒违抗
mechanical power transmission 机械动力传输
It can be divided easily to serve individual loads or recombined to power a high,
single-load demand. 液压可以方便的将动力分成多个载荷分支，也可以方便的将动力重新组合
以适应单一的大载荷。 divide
v.
划分分裂隔开瓜分划开 serve
v.
服务 individual
a.
个
人个别个体分别 recombined 重组
Electrical and pneumatic power distribution have similar flexibility, but lack the
compactness and certain of the other important characteristics of hydraulics. 电力与气
动在动力分配上具有同样的灵活性，但与液压相比，缺乏紧凑性和一些其他的重要特性。
electrical 电 pneumatic
a.n.
气动风动空气的 distribution
n.
分布分配分发布局
flexibility
n.
灵活性挠性机动性 lack
v.n.
缺乏短少 compactness
n.
紧凑简洁 certain
a.n.
一些某些肯定确定 important a.重要 characteristic n.特点特性特征 hydraulics
n.
水力学水利液压
10、A very significant feature of hydraulic power is its extreme power density. Fig.10.1
shows a comparison of a 400 hp(1hp=0.7457kW) hydraulic pumping source with a diesel engine
and an electrical motor of the same power capacity. 液压传动的一个显着特性就是它具有
极高的能量密度，如图10.1所示，一个400马力(1hp=0.7457kW)的液压泵和相同功率的柴油发动
机以及电动机的比较图。 significant
a.
重大重要显着有意义 feature
n.
特性特点特征
hydraulics
n.
水力学水利液压 extreme
a.
极端极度偏激
n.
极点 density
n.
密度 power
density 动力密度比功率 comparison
n.
对照比拟 pump
v.
抽抽水
n.
抽水机 source
n.
源
源头根源 diesel
n.
柴油机 diesel engine 柴油发动机 electrical motor 电力马达电动机
capacity
n.
容量
The contrast is obvious and is one that offers both an opportunity to the user of hydraulic
power and a challenge to the designer of hydraulic components. 差别是明显的，而且这种
对比不仅仅对液压系统的使用者是一个机遇，对液压组件的设计者也同样是一个挑战。 contrast
n.
对比对照比照
v.
比较 obvious
a.
明显显然 offers
v.
提供 opportunity
n.
机会机遇时
机 challenge
n.v.
挑战 component
n.
元件构件组成部件
11、The high- power density in a hydraulic pump or motor creates design challenges beyond
those found in many other products. 液压系统的高能量密度还对液压系统以外的其他产品的设
计构成了挑战。 power density 动力密度比功率 create
v.
创建创造制造造成创作导致
design
v.n.
设计计划 challenge
n.v.
挑战 beyond
p.
以外 found
v.
创立创建建立制造
product
n.
产品
High loads on rapidly sliding surfaces, extreme fluid velocities and rapidly recurring
pressure applications on pumping elements (vanes, pistons, gears) demand careful design
attention to assure long life, complete reliability and efficient operation. 快速滑动
表面上的大载荷、高速的流体以及作用于泵原件（叶片、活塞、叶轮）上的快速恢复压力，这些
都需要经过精心的设计去实现保证长寿命、可靠性和高效执行。 rapidly
ad.
急速赶紧 slide
n.v.
滑动滑行 surface
n.
表面面
a.
表面的肤浅的 extreme
a.
极端极度偏激
n.
极点 fluid
n.a.
流体液体 velocity
n.
速度 recur
v.
复发回到 pressure
n.
压力 application
n.
应用
运用采用 pumping elements 泵体零件 vane
n.
叶片 piston
n.
活塞 gear
n.
叶轮 demand
n.v.需求需要 attention
n.
注意关注 attention to 注意 assure
v.
保证担保保险承担
应诺 complete
v.a.
完成完毕完整完全完善彻底全部 reliability
n.
可靠性 efficient
a.
有效的 operation
n.
操作行动作业手术
The user, on the other hand, reaps the benefit of a family of apparatus that is highly
responsive, finely controllable and simple to apply. 同时，使用者得到的回报是全系列的
产品，而且，这些产品还是高回报、精细控制、简单易用。 reap
v.
收割收获 benefit
v.n.
好
处利益效益盈利 apparatus
n.
设备 response
n.
响应反应应对解答 finely 精细良好
优良
When the designer understands the user’s needs and the user understands the equipment’
sfull capabilities, the maximum potential of hydraulic power can be achieved. 当设计
者了解了客户的需求，使用者明白了这些设备的各种功能以后，液压系统的潜能得到了最大的发挥。
potential
n.a.
潜力趋势势能 PT电压测试仪
Unit 12 Fluid Mechanics in Engineering
流体力学的应用
一、New words and expressions
二、Translation
Fluid Mechanics in Engineering
流体力学的应用
1、Fluid Mechanics is the branch of engineering science that is concerned with forces and
energies generated by fluids at rest and in motion.
fluid
n.a.
流体液体
mechanics
n.
力学，机械学
branch
n.
分支部门
concerned 关心关系有关 be concerned with与…有关
energy
n.
能源能量能力
rest
n.v.
休息
流体力学是工程学的一个分支，它是研究流体在静止状态与运动中的情况下所产生的力与能量的一
门科学。
The study of fluid mechanics involves application of the fundamental principles of
mechanics and, to a lesser degree, of thermodynamics to develop a qualitative understanding
and quantitative analysis techniques that an engineer can apply to design or evaluation
of equipment and processes that involve fluids.
involve
v.
涉及包括牵涉包含涉牵扯累及卷入带有意味着牵连波及连累累意味
缠攀带累笼罩
application
n.
应用申请应用程式运用申请书用途采用用场诉状采取议案意见
fundamental
a.
根本基本的
n.
基本原理基调
principle
n.
原则原理道理信念学说道意向机宜
fundamental principles基本原理
thermodynamic 热力热力学热动力学
qualitative
a.
质的性质上的定性的qualitative analysis定性分析
quality
n.
质量品质素质质性质品性成色色
a.
最高品质的
quantitative
a.
量定量的 quantitative analysis定量分析 quantity
n.
数量量份量额
technique
n.
技术技巧术手法表演法
analysis
n.
分析分解
evaluation
n.
评价评估评测 evaluate
v.
评估评价评定估价鉴定作价评说折价
equipment
n.
设备装备装置具武装
process
n.
过程进程加工对...处置
v.
处理提炼
流体力学研究的内容包括应用力学基本原理和少量热力学基本原理来发展一种定性理解和定量分析的方法，使工程师能用于设计或评估与流体有关的设备和工艺过程。
2、You are probably reading this book because fluid mechanics is a required course in your
curriculum.
course
n.
课程过程进程历程期间航向航线航道经过轨道路程轨程序 required
course 必修课 selected course 选修课
curriculum n.课程课表
你也许正在读这本书，因为流体力学是你所修课程中的一门必修课。
The study of fluid mechanics is included in most engineering curricula because the
principles and methods of fluid mechanics find many technological applications.
curricula
n.
课程
在多数工科教学中都包含有流体力学的学习内容，因为流体力学的原理和方法得到了很多巧妙
的应用。
To illustrate a few applications, we will consider the following fields:
① Fluid transport；
② Energy generation；
③ Environmental contro1;
④ Transportation．
illustrate
t.
（用图、实例等）说明，阐明显示演示图解说明绘图
下列领域，或多或少的都会涉及到流体力学：
① 液体传输
② 能量形成
③ 环境控制
④ 运输业
3、Fluid transport is movement of a fluid from one place to another so that the fluid may
be used or processed.
transport
n.
运输输送运转运输航运
v.
传输运送搬运搬盘运盘
流体运输是指将液体从某地到另外一个地方的运动过程，以便对流体进行利用或加工。
Examples include home and city water supply systems, cross-country oil, natural gas,
and agricultural chemical pipelines, and chemical plant piping.
include
v.
包括包含括包囊括收录包罗收入并把赅算
supply
v.
提供供应供给供给补给输送补输接应给以资上补发赍
n.
输送输
agricultural
a.
农业的农艺的 agriculture
n.
农业农农农艺
比如：家庭和市区的供水系统，跨国石油管道，天然气管道，农业化学品管线以及化工厂管网
等。
Engineers involved in fluid transport might design systems involving pumps,
compressors, pipes, valves, and a host of other components all directly involved with
motion of fluids.
involve
v.
涉及包括牵涉包含涉牵扯累及卷入带有意味着牵连波及连累累意味
缠攀带累笼罩
transport
n.
运输输送运转运输航运
v.
传输运送搬运搬盘运盘
pump
v.
抽抽水打气
n.
抽水机
compress
v.
压缩压紧压碎 compressor
n.
压缩机
valve
n.
阀阀门瓣膜瓣活门活塞闸门灯
a host of许多，大量
component
n.
元件部件组成构件分枝
a.
组成的
涉及流体输送的工程师们在系统设计时，需要包含各种与流体运动直接相关的泵、压缩机、管
道、阀门以及大量的，与流体运动直接相关的其它部件。
In addition to the design of new systems, engineers may evaluate the adequacy of
existing systems to meet new demands or they may maintain or upgrade existing systems.
evaluate
v.
评估评价评定估价鉴定作价评说折价 evaluation
n.
评价评估评测
adequacy
n.
充足适当足够是否足够是否充足充足性充足率
maintain
v.
保持维持维护保留维修保养保持主张养护认定保全树立安定拥护
maintenance n.维持，保养，维修，抚养
upgrade
n.
升级
v.
提升
除了设计新的系统之外，工程师们还需对现有系统进行充裕性评估以满足新的需要，或是对现
有系统进行维护或升级。
4、In the field of energy generation, we find that, with the exception of chemical batteries
and direct energy- conversion devices such as solar cells, no useful energy is
generated without fluid movement.
exception
n.
例外反驳不赞同不赞成责备
battery
n.
电池组炮台炮兵连 chemical battery 化学电池
cell
n.
细胞电池元件牢房蜂房密室 solar cell 太阳能电池
在能源生产领域，我们知道，除了化学电池和能量直接转化装置如太阳能电池之外，其它所有有
效能源的产生均离不开流体运动。
Typical energy- conversion devices such as steam turbines, reciprocating engines, gas
turbines, hydroelectric plants, and windmills involve many complicated flow processes.
steam turbines 蒸汽轮机蒸汽涡轮机
reciprocating engines往复式发动机
gas turbines燃气轮机
hydroelectric plant 水电站
windmill 风车
complicate 复杂
典型的能量转化装置，诸如如蒸汽轮机、往复式发动机、燃气轮机、水力发电厂以及风车都涉
及到许多复杂的流体过程。
In all of these devices, energy is extracted from a fluid, usually in motion.
extract vt.抽出用力取出使劲拔出提取提炼摘录选用
在所有这些装置中，能量均从某种流体中得到，而流体通常是运动中的。
The thermodynamic cycles of these devices usually require fluid machinery such as pumps
or compressors to do work on the fluid.
thermodynamic 热力热力学热动力学
cycle
n.
周期循环周学时
v.
骑车轮转
machinery
n.
机械机器机械装置
这些装置的热力学循环，通常需要有流体机械，如泵类、压缩机，对流体做功。
Auxiliary equipment such as oil pumps, carburetors, fuel-injection systems, boiler,
draft fans, and cooling systems also depends on fluid motion.
auxiliary
a.
副辅附属辅助的附加的
n.
辅助者辅助物
carburetor n.化油器
fuel-injection systems 燃油喷射系统
boiler n.锅炉 boil
v.
烧开熬煮煲滚沸煮熟烹n.沸腾脓肿
draft fan 抽风机
辅助设备，诸如油泵、化油器、燃油喷射系统、锅炉、排风扇以及冷却系统也都依赖于流体的
运动。
5、Environmental control involves fluid motion.
environmental
a.
环境的 environment
n.
环境周围
环境控制也涉及流体运动。
An estimated 75 percent of American homes are heated by forced-air systems，in which
the home air is continually recirculated to transport heat from the combustion of fuel.
estimate
v.
估计预计估估量测度计量揣度揣臆测
n.
预算量
force
n.
力力量武力部队动力势力暴力势强兵威武
v.
强行迫使强迫逼迫逼迫
胁迫强加胁要逼勒
continually
ad.
不断持续继续连续
recirculate 循环 circulate
v.
流通流传发行 circul 圆弧 circu 环流
transport
n.
运输输送运转运输航运
v.
传输运送搬运搬盘运盘
heat
n.
热热力热度热气燥热暑暑气
v.
发热煲
combustion
n.
燃烧
fuel
n.
燃料薪
v.
加燃料
据估计大约75%的美国家庭利用压力气体系统来取暖，在该系统中，家庭内的空气连续不断地进
行循环以传送来自燃料燃烧的热量。
In air- conditioning systems the circulating air is cooled by a flowing refrigerant.
circulate
v.
流通流传发行 circul 圆弧 circu 环流recirculate 循环
refrigerant 制冷剂 refrigerantor 冰箱电冰箱冷藏室freezer 冷冻室
在空调系统里，循环的空气被流动的致冷剂冷却。
Similar processes occur in automobile engine cooling systems, in machine tool cooling
systems, and in the cooling of electronic components by ambient air.
ambient 环境环境温度周围环境
在汽车发动机冷却系统中，机床冷却系统中和电子器件的冷却系统中都是与此过程相类似的，电
子器件的冷却是由周围的空气来完成。
6、With the exception of space travel, all transportation takes place within a fluid medium
(the atmosphere or a body of water).
exception
n.
例外反驳不赞同不赞成责备
除了太空旅行，所有运输均发生在流体介质内（或大气中或水体里）。
The relative motion between the fluid and the transportation device is responsible for
the generation of a force that opposes the desired motion.
流体和运输工具间的相对运动，产生了期望运动方向的反力。
This force can be minimized by the application of fluid mechanics to vehicle design.
这种反力可以通过车辆的流体力学上的设计而降低到最小。
The fluid often contributes in a positive way, such as by floating a ship or generating
lift by air motion over airplane wings.
contribute
v.
有助于贡献捐助捐献缴纳捐赠投稿捐建树合作立功contribution
n.
贡献捐助汗马功劳功绩 contributive
ad.
贡献出资
float
v.
浮动浮漂浮飘漂飘动飘荡泛
n.
浮筒浮游物彩车
generat
v.
产生generator发生器发电机母线
lift
n.
电梯elevator 升降机升程
v.
抬举起举提掀起升高开放拔揭剽窃空运抄袭
竖起昂扬
wing
n.
翼翅膀翅羽翼边锋膀膀子
v.
空运装以翼
ship
n.
船舰；飞船，飞艇，大型飞机（美口语）
by
prep
.(介词)就…来说（表关系）
流体也常有正面的作用，比如利用掠过机翼的空气所产生的浮力可以托起一架飞机。
In addition, ships and airplanes derive propulsive force from propellers or jet engines
that interact with the surrounding fluid.
derive
v.
派生导出推导推导出中获得导源
propulsive 推进推进力
propeller
n.
螺旋桨推进器
interact
v.
相互作用相互影响
n.
幕间休息
surround
v.
环绕包围周围围围住抱拱抱拱困
n.
镶边
同时，船和飞机从螺旋桨或喷气式发动机获得推进力，这个推进力是螺旋桨或喷气式发动机与
周围流体之间的相互作用而获得的。
7、These examples are by no means exhaustive.
by no means exhaustive 不胜枚举并非详尽无遗exhaustive
a.
详细彻底的全面的 exhaust
v.
排气耗尽排出尽竭尽竭用光耗竭穷竭殚澌吃殚竭废语枯窘
n.
用尽排气尾气
类似的例子不胜枚举。
Other engineering applications of fluid mechanics include the design of canals and
harbors as well as dams for flood control.
canal
n.
运河，沟渠，水道
harbor
n.
港湾，海港；避难所，避风港
dams
n.
水坝
flood
n.
洪水水灾洪汛滥
v.
泛滥淹没注满滔喷
流体力学在工程方面的应用还很多，比如运河、港口以及为控制洪水的堤坝。
The design of large structures must account for the effects of wind loading.
account
n.
帐户帐记事诉说诉状
v.
占认为认定
大型建筑的设计必须考虑风载的影响。
In the relatively new fields of environmental engineering and biomedical engineering,
engineers must deal with naturally occurring flow processes in the atmosphere and lakes,
rivers, and seas or within the human body.
environment n.环境周围 environmental a. 环境的
biomedical 生物医学
deal with
v.
处理处置应付办理周旋处从事办待应经手来往贩营支应
natural
a.
自然天然固有当然迹先扑质蒙昧的
n.
白痴天然的东西naturally
ad.
自然理
所当然自是
occur
v.
发生遇遇见蕴蓄来遇合蕴
在环境工程和生物医学等相对新兴领域，工程师们还必须应付自然存在的流体的流动过程，包括
在大气中、湖泊中、河流中、大海中以及人体内的流动过程。
Although it is not usually considered an engineering discipline, the phenomena of fluid
motion are central to the field of meteorology and weather forecasting.
consider
v.
考虑认为研究虑思量算看成酌量思深思思虑思忖酌意动脑筋忖讲
熟思
disciple
n.
弟子门徒徒弟信徒 discipline
n.
纪律学科专业纪规律课程风纪学术
v.
惩戒训练律惩锻
phenomena
n.
现象
meteorology
n.
气象
weather forecasting 天气预报
尽管一般来讲，不认为气象学和天气预报是工程类学科，但是，流体运动现象仍是气象学和天气
预报的核心。
8、Few engineers can function effectively without at least a rudimentary knowledge of fluid
mechanics.
rudimentary
a.
初步起码低级
很少有工程师能够一点不懂流体力学的基本知识，就能有效地发挥作用的。
Large numbers of engineers are primarily involved with processes, devices, and systems
in which a knowledge of fluid mechanics is essential to intelligent design, evaluation,
maintenance or decision making.
primarily 主要
involve
v.
涉及包括牵涉包含涉牵扯累及卷入带有意味着牵连波及连累累意味
缠攀带累笼罩
process
n.
过程进程加工对...处置
v.
处理提炼
essential
a.
必要必不可少必需根本要紧
n.
要点要领
intelligent
a.
智能聪明聪慧聪颖慧聪懂事心灵机灵合理的
evaluation
n.
评价评估评测 evaluate
v.
评估评价评定估价鉴定作价评说折价
maintain
v.
保持维持维护保留维修保养保持主张养护认定保全树立安定拥护
maintenance n.维持，保养，维修，抚养
decision
a.
决断定案果断主意裁
多数工程师从事工艺、设备和系统等方面的工作，在这些工作中，流体力学的知识对于聪颖的设
计、评估、维护与决策制定是至关重要的。
You probably cannot foresee exactly what problems you will be called on to solve in your
professional career; therefore, you would be wise to obtain a firm grasp of the fundamentals
of fluid mechanics.
foresee
v.
预知预料料到预卜未卜先知意想意意料预段
exactly
ad.
准确究竟恰好刚好恰恰就是恰整刚刚 exact
a.
确切精确准确准过份周
到的过份注意的
v.
索取索掊罚金罚款 exaction n.勒索苛求摊派
professional
a.
专业的行
n.
专业人才
career
n.
事业生涯速度
wise
a.
明智英明高明合理聪哲
firm
n.
公司企业厂商果断
a.
坚定坚决牢固稳固坚固坚严格硬稳健固牢牢靠决
心狠刚确刚强硬性监磐严竣
v.
加固加强弄结实
ad.
坚固地坚硬地
grasp
v.
把握掌握了解领会握把秉捉持执意识掺操
fundamental
a.
根本基本的
n.
基本原理基调
你也许不能准确预见你的职业生涯中将会面对什么样的问题，但你牢固把握流体力学的基础知识
肯定是应明智的。
9、These fundamentals include a knowledge of the nature of fluids and the properties used
to describe them, the physical laws that govern fluid behavior, the ways in which these
laws may be cast into mathematical form, and the various methodologies (both analytical
and experimental) that may be used to solve engineering problems.
fundamental
a.
根本基本的
n.
基本原理基调
natural
a.
自然天然固有当然迹先扑质蒙昧的
n.
白痴天然的东西naturally
ad.
自然理
所当然自是
cast
v.
投投射抛撒下撇付
n.
铸件抛掷辗转
methodology
n.
方法论
这些基础包括对下列问题的了解：流体的种类，以及用来描述流体的那些属性、支配流体行为的
物理学定律、由这些物理学定律生成的数学模型方法和那些用来解决实际问题的方法（既包括分析
的方法，也包括实验的方法）。
Unit 14 Quality Assurance and Control (1)
质量保证与控制
产品质量是生产中最重要的。如果放任质量恶化下去，生产者会很快发现销售量锐减，可
能从而会导致产业的失败。用户期望他们买的产品质量性能好，而且如果制造商想建立并
维
持其信誉，
必须在产品制造前制造过程中及制造过程后进行质量控制和质量保证。
一般来说，
质量保证包括所有的活动，
其包括质量建立和质量控制。
质量保证可以被分为三个主要领域，
他们如下所述：
①制造之前的原材料的检查
②在制造加工过程中的质量控制
③制造之后的质量保证
生产制造后的质量控制包括保证书和面对产品用户的服务。
生产制造之前的原材料检验
质量保证常常在实际生产制造之前就开始了。
这些都是生产者在供应原材料、
散件或配件
的车间里进行检验。生产制造公司的原材料检验员到供应厂并且检查原材料及于制造的另
配
件。原材料检验为生产者提供了一次机会，那就是在原料及散件被运到生产车间之前先进
行
挑选淘汰。原料检察员的责任是去检查原料和零件是否达到设计规格并且淘汰那些未达到
特
殊指标的原料。原料检验有很多于检查产品相同的检验。其如下所述：
①目测
②冶金测试
③尺寸测试
④损伤检验
⑤性能检验
目测
目测检验一种产品或原料的某些特征，如颜色、纹理、表面光洁度或部件的总体外观，从
而判断其是否具有明显的缺损。
冶金测试
冶金测试常常是原料间严厉的一个很重要的部分，
尤其是像棒料、
建筑材料毛坯一些原材
料。金属测试包含所有主要的检验类型，其中有目测，化学检验，光谱检验和机械性能检验，
其包括硬度、伸缩性能、剪切性能、压缩性能和合成成分的光谱分析。冶金测试既可用于
成
品件也可用于预制件。
尺寸检验
质量控制的一些领域是重要的生产件的要求尺寸。
尺寸在检验过程中，
像其在生产过程中
一样重要。如果这些零件是为总成供应的，那尺寸尤其严格。一些尺寸在生产车间用标准
测
量工具进行检验，像特种接头、造型和需求的功能标准度量。符合尺寸规格对所制造多部
件
的互换性和对多部件成功组装成复杂的装置，如汽车、轮船、飞机和其他多部件产品都地
极
其重要的。
损伤检验
在一些情况下，
对原材料或零部件采取损伤测试的原始测验是很必要的。
特别是涉及到大
批的原材料时。例如，在被运到生产车间作最终机器之前，对铸件进行
X-
射线、电磁离子、
染色渗透剂技术的探伤是很必要的，又对机器总成的电子或持久运作测试而确定的规格，
是
无损测试的又一例证。有时，对材料及零件的测试是很必要的，但由于无损测试的花费和
成
本及时间不是任何时候都允许的。
例如，有压力测试决定在设计中其是否安全。损伤测试经常用于设计样机的测试，
而不是
原材料或零件的常规检验。一旦设计达到了所希望的材料强度，通常对零件做进一步的损伤
测试是不必要的，除非他们确实存在疑点。
性能测试
性能测试在零部件被其他产品被安装之前，
检查部件的功能，
尤其是那些机械构造复杂的
部件。例如电子设备零件，飞机和汽车发动机，泵、阀及其他需要在装运和最后安装前进行
性能测验的机械系统。
选自《现代材料和制造工艺》
Unit15controlsystemfundamentals
(1)Numeric allycontrolledmachinesoftenweighupto100tonsandyeta rerequiredtopositionacutt
trolsystemmustmovethe toolatfederatesas
highas8achinem
usthavedyna micresponsecharacteristicsthatenableittofollowintr icatecontourswithaminimu
y,theserequirementsdic tateacontrolsystemthatismatchedtothemechanic
al characteristicsofthemachineitdrives.
数控机械通常重达1 00吨，可是却要求安装一个精度高达0.002mm数量级的切削刀具。在遇到预定
路径下载荷变化较大的情况时，控制系统仍要以高达8厘米秒的进给速度下移动刀具。数控机床
必须具有动态响应特性，使它能够复制较复杂的轮廓线，并具有最小的路径误差。显然，这些条件
要求控制系统必须与它所驱动的机器机械特征相匹配。
(2)Acontrolsystemisacombinationofdev icesthatregulateanoperationbyadministeringtheflow ially,acontrolsystemismadeupofi
nterrelateds ubsystemsthatperformtaskswhichinorthodoxmachiningp rocessesaremanagedbyani
ntelligenthumanoperator .
控制系统是一组设备的组合，他通过管理能量流和与该操作有关的其它资源来控制操作。从本质上 说，控制系统由相互关联的子系统组成，并有它们执行传统上通常由只能人工操作员控制的机械加
工过程。
(3)ThecontrolsystemsforNCmachinestherefor eservetoreplacethehumanmachineoperatorandsig
ta nalogycanbemadebetweennumeri
:
因此，数控机床的控制系统用于代替人工机器操作员并可显着地改进即使最好的人工操作。可从以
下几个方面对数字控制系统和它们代替的人工操作员直接进行类比：
①Sensethecurrentstatusofthemachine;
②Makel ogicaldecisionswhicharerequiredtoaccomplishatask;
③Communicatedecisionstothemachinebyactuatingpr opermechanicaldevices;
④Havetheabilitytostorei nformation:instructions,data,andtheresultsoflogica l
decisions.
①检测机器的现状；
②做出完成任务所需的逻辑决策；
③通过操纵机械设备向机器传送决策信息；
④具有储存指令、数据、与逻辑决策结果等各种信息的能力。
(4)Insummary,a machinecontrolsystemisacombinationofelectroniccirc uitry,sensingdevices,
andmechanicalcomponentswh ichguidethecuttingtoolalongapredefinedpath.总之，机械控制系统
是电路系统、检测装置以及机器零件的结合体，并指导切削刀具沿着预定路径实现进给动作。 (5)Inthesectionsthatfollow,thereaderisintroduced tothetheoryofmachinecontrol.以下的内
容，将给读者介绍机械控制的原理。
(6)Wehaveattributedfourmajorcharacteristics toanycontrolsystem:theabilitytosensedata;m
akel ogicaldecisions;communicateandactuate;temperfo
rmsthesefunctionswithouttheaidofahumanoperator,byd efinitionitautomaticallycontrolsagi
onsiderones uchsimpleoperation.
译文：我们已经总结了所有控制系统具有的四个主要特征：监测数据的能力；做出逻辑决策；通讯
及操纵机械；及在内存中存储信息。如果系统在不借助人工帮助下执行这些操作，根据定义它是自
动地控制给定任务。让我们考虑下面这个简单的操作。
(7) Supposethatane
eratesmoothlytheconveyormustmain tainaconstantspeedasadditionalloadsareaddedfromloa din
ssumethatthespeedofrotationofanelectricmoto risdirectlyproportionaltothe
stheloadincreaseso ntheconveyor,thetorquerequirement
ofthemotorisi us
uallyachievedbyincreasingthesupplyvoltage. 译文：假设电子马达被用于某建筑物两层楼的货物传送，为了顺利操作，当额外的载荷被加上时，
传送带必须维持恒定的速度。我们可以假设，电动机马达的转速和直接所供给的电流成正比。因此，
当传送带上的载荷增加时，马达的扭矩要求增加，因此为了维持恒定的速度必须提供附加的动力，
这通常通过增加供给电压来实现。
（8）
Ifamotorspeedindicatoriswith insightofahumanoperator,hecancontroltheconveyorspe edbyinc
ystemisillustratedschematicallyin
如果一个电机的速度指示器在人类操作者的视线范围内，他可以通过手动增加或减小电源电压来控
制传送带速度。该系统如图15.1所示。
（9）
AsindicatedbyFig.15.1(a ),
ically,unicatesadecision,
byactuatingthep owersupplycontrollever,toincreasevoltageuntilthede siredspeedreadingiso
.15.1(b)thedesiredspeedisr ead;hence,oadis
decreasedsothataspeedgreatertha nthedesiredvalueisregisteredinFig.15.1(c),theopera torw
illdecreasevoltage.
（10）
Theprocess describedaboveisillustratedschematicallyinThesyste mindicatedinthefigureisno
r,ifthehumanoperatorb lockwerereplacedwithadevicethatperformedthefunc
tionsshown,anautomaticcontrolsystemwouldberealize d.上述过程如示意图15.2所示。图中所示
的系统并不会自动化的。然而。如果操作员模块用一个设备替换，并执行所显示的功能，自动控制
系统将会实现。
（11）
mechanis mmaybeacomplex
arrlessofthecom
plexityofthes ervomechanism,italwaysexhibitsthefeaturesillustrat edin
自动控制系统有时被称作伺服机械。伺服机械或者是机电元件的复杂组合，或者就是一个简单的机
械装置。不管伺服机械是否复杂，它总是具有如图15.2所示的那些特性。
(12)C onsiderasimplemechanicaldevicethatperformstheautom aticcontrolfunctionforourconve
yorsystem(Fig,15 .3).Suchadevice,calledaWattspeedgovernor,canautoma ticallycontrolthesp
eedofanelectricmotor.
考虑执行我们的输送机系统的一个简单的机械设备(Fig.15.3)。这样的设备，称为瓦特调速器，可
以自动地控制一台电动机的速度
(13)AsshowninFig.15.3,theWatts peedgovernorconsistsoftwoweightedarmsconnectedtoas haft,
S2,orshaft,S1,iscoupledtothegovernorshaft ,S2,sothattherotationalvelo
rspeedincreases,cen trifugalforcemovestheweights,W,ou
tward,causing theweightedarmstorotatethroughsomeangle,
θ.Thew eights,angle,andsleevepositionarechosensothatthepr operspeedwillcausethevoltage
ionsinspeedwillcau setheappropriatem
ovementofthesleeveandlever.
。
Unit 16 Open-loop and Closed-loop Control
Open-loop Control Systems (Nonfeedback Systems) 开环控制系统（无反馈系统）
The word automatic implies that there is a certain amount of sophistication in the
control system. By automatic, it generally means that the system is usually capable of
adapting to a variety of operating conditions and is able to respond to a class of inputs
satisfactorily. 自动化一词意味着在控制系统中有一定数量采用先进的技术，它通常意味着系统
有普遍适应的能力，对于操作环境的变化能够响应一类令人满意的输入However, not any type of
control system has the automatic feature. Usually, the automatic feature is achieved by
feeding the output variable back and comparing it with the command signal. When a system
does not have the feedback structure, it is called an open-loop system， which is the
simplest and most economical type of control system. 然而，不是任何一个控制系统都具有
自动化特征。通常，控制特征是通过反馈输出变量和比较控制信号获得的。当一个系统没有反馈结构，这称为开环系统，开环系统是最简单而且最经济的控制系统类型。Unfortunately ,open-loop
control systems lack accuracy and versatility and can be used in none but the simplest
types of applications. 不幸的是，除了最简单的应用类型，开环控制系统，由于缺乏精确度和
多功能不被应用。
Consider, for example, control of the furnace for home heating. Let us assume that
the furnace is equipped only with a timing device, which controls the on and off periods
of the furnace. To regulate the temperature to the proper level, the human operator must
estimate the amount of time required for the furnace to stay on and then set the timer
accordingly. When the preset time is up, the furnace is turned off. 考虑一下，例如，用
于家庭取暖的火炉的控制。假设火炉仅配有时间装置，控制火炉周期内的开启和关闭。操作者必须
估计火炉达到理想温度所需要的时间，然而设置计时器，当达到预先设计的时间时火炉关闭，
However, it is quite likely that the house temperature is either above or below the desired
value， owing to inaccuracy in the estimate. Without further deliberation, it is quite
apparent that this type of control is inaccurate and unreliable. 房间的温度也可能高于
或者低于期望值，原因就是估计不精确不从长远考虑，很明显这样控制的类型是不精确不可靠的。
One reason for the inaccuracy lies in the fact that one may not know the exact
characteristics of the furnace. The other factor is that one has no control over the outdoor
temperature, which has a definite bearing on the indoor temperature This also points to
an important disadvantage of the performance of an open-loop control system，in that the
system is not capable of adapting to variations in environmental conditions or to external
disturbances. 一个列出事实关于精确性的原因可能是不知道火炉准确的特征，另一个原因是不能
控制外界的温度确切的对室内温度的影响，这也指出了开环系统特征的重要缺点，因此不能适应环
境条件或者外部干扰的变量。 In the case of the furnace control, perhaps an experienced
person can provide control for a certain desired temperature in the house; but if the doors
or windows are opened or closed intermittently during the operating period, the final
temperature inside the house will not be accurately regulated by the open-loop control.
关于火炉控制，一个经验丰富的人可能能够控制室内的温度，但是如果门窗都开着或者在火炉运行
期间间歇地关闭，屋内最终的温度通过开环控制系统就不会被调整得很精确了。
An electric washing machine is another typical example of an open-loop system, because
the amount of wash time is entirely determined by the judgment and estimation of the human
operator. A true automatic electric washing machine should have the means of checking the
cleanliness of the clothes continuously and turn itself off when the desired degree of
cleanliness is reached. 洗衣机也是开环系统中一个典型的例子，因此洗衣的时间是通过操纵者
来判断和估计的，一台真正的自动洗衣机应该具有连续检查衣服的清洁度的方法。当衣服达到一定
的清洁度时自动关闭 Although open-loop control systems are of limited use, they form the
basic elements of the closed-loop control systems. In general the elements of an open-loop
9

control system are represented by the block diagram of Fig. 16. 1. An input signal or command

r
is applied to the controller, whose output acts as the actuating signal
e;
the actuating
signal then actuates the controlled process and hopefully will drive the controlled
variable c to the desired value. 尽管开环控制系统使用受限，它是形成闭环控制系统的基本
元件，通常一个开环系统的元件如图16所示，一个输入信号或者命令r应用到控制器上，它的输
出作为激励信号e，然后激励信号激励控制过程希望通过驱动控制变量C得到预期值。
What is missing in the open-loop control system for more accurate and more adaptable
control is a link or feedback from the output to the input of the system. 在开环控制系
统中为了获得更高的精确性和更高的适应性，所缺少的是一个环节或者从系统的输出到输入的反馈
In order to obtain more accurate control，the controlled signal
c(t)
must be fed back
and compared with the reference input, and an actuating signal proportional to the
difference of the output and the input must be sent through the system to correct the error
①. 为了获得更精确的控制，必须将被控制信号C（t)反馈回去与参考输入量相比较，且须将与输
出和输入之差成比例的促动信号送给系统以矫正偏差A system with one or more feedback paths
like that just described is called a closed-loop system. Human beings are probably the
most complex and sophisticated feedback control system in existence. 如刚才所说的一样，
含有一个或者多个反馈路线的系统称为闭环系统，人类可能现有最复杂最精密的反馈系统A human
being may be considered to be a control system with many inputs and outputs, capable of
carrying out highly complex illustrate the human being as a feedback control
system, let us consider that the objective is to reach for an object on a desk. As one
is reaching for the object, the brain sends out a signal to the arm to perform the task.
The eyes serve as a sensing device which feeds back continuously the position of the hand.
The distance between the hand and the object is the error, which is eventually brought
to zero as the hand reaches the object. This is a typical example of closed-loop control.
人类可以被认为含有很多输入输出的控制系统，具有执行相当复杂的操作能力，让我们考虑一下，
目标是够到桌子上的一个物体，当人正接近物体时，大脑发出信号手臂执行任务，眼睛作为窗安装
置不停地反馈物体位置，手和物体之间的距离是误差，误差最终变为0时，手刚好够到物体，这就
是一个典型闭环反馈的例子However, if one is told to reach for the object and then is
blindfolded, one can only reach toward the object by estimating its exact position. It
is quite possible that the object may be missed by a wide margin. With the eyes blindfolded,
the feedback path is broken, and the human is operating as an open-loop system. The example
of the reaching of an object by a human being is described by the block diagram shown in.
然而，如果一个人蒙着眼睛去够物体，他仅仅是通过估计去接近物体的真实位置，在很大程度上他
可能丢失目标，由于眼睛被蒙上，反馈路线被破坏，人的操作就变成了开环系统，人够物体的例子
可以描述成图16.2
As another illustrative example of a closed-loop control system, Fig. 16. 3 shows the
block diagram of the rudder control system of a ship. In this case the objective of control
is the position of the rudder, and the reference input is applied through the steering
wheel. The error between the relative positions of the steering wheel and the rudder is
the signal, which actuates the controller and the motor. When the rudder is finally aligned
with the desired reference direction, the output of the error sensor is zero. 另一个
闭环系统的例子，图16.3所示的船舵控制系统，在这个例子中控制的目标是船舵的位置，参考输
入是舵轮，舵轮的相对位置和船舵之间的误差是一个信号。信号激励控制器和发动机，当船舵最
终调整到期望的参考位置时，传感器的输出误差为0
The basic elements and the block diagram of a closed-loop control system are shown
in
Unit
17
Feedback and Its Effects
The concept of feedback plays an important role in control system.s. Feedback is
a major requirement of a closed-loop control system. Without feedback, a control system
would not be able to achieve the accuracy and reliability that are required in most
practical applications. 在控制系统中，反馈充当着一个重要的角色。闭环控制系统中一定存
在反馈，如果没有反馈，一个控制系统就不能够获得在实际应用中所要求的精度和可靠性In
reality, the reasons for using feedback carry far more meaning than the simple one of
comparing the input with the output in order to reduce the error. The reduction of system
error is merely one of the many effects that feedback may bring upon a system. 事实
上，运用反馈有着很重要的意义，而不仅仅是为了减小误差比较输入与输出。系统误差的减小仅
仅是引入反馈带来的影响之一W e shall now show that feedback also has effects on such
system performance characteristics as stability, bandwidth* overall gain, impedance,
and sensitivity. 我们现在可以认识到反馈对于系统的性能特性也有很大的影响，例如稳定性、
带宽、总增益、阻抗和灵敏度。
To understand the effects of feedback on a control system, it is essential that we
examine this phenomenon with a broad mind. When feedback is deliberately introduced for
the purpose of control, its existence is easily identified. 为了了解反馈对于控制系统的
影响，很明显我们需要以一个开阔的思维去思考它。当为了控制而故意地引入反馈，那么反馈的存
在很明显 However, there are numerous situations wherein, a physical system that we normally
recognize as an inherently nonfeedback system may turn out to have feedback when it is
observed in a certain manner. 但是，在物理系统中有很多的状况，一些我们认为没有反馈的系
统，当我们换一种角度研究时，它是有反馈的。 In general we can state that whenever a closed
sequence of cause-and-effect relation exists among the variables of a system, feedback
is said to exist. This viewpoint will inevitably admit feedback in a large number of systems
that ordinarily would be identified as nonfeedback systems. 通常，我们可以指出，只要系
统的变量之间存在闭合序列的因果关系，就认为存在反馈。在很多被认为无反馈系统中，这个观点
不可避免地承认了反馈。
We shall now investigate the effects of feedback on the various aspects of system
performance. Without the necessary background and mathematical foundation of linear system
theory, at this point we can only rely on simple static system notation for our discussion.
我们将研究反馈对于系统性能的各个方面的影响。没有必要的背景和线性系统理论的教学基础，对
于我们的讨论我们只能依靠简单的静止系统注释Let us consider the simple feedback system
configuration shown in Fig. 17. 1, where r is the input signal, c the output signal,
e

the error, and 6 the feedback signal. The parameters
G
and
H
may be considered as constant
gains. By simple algebraic manipulations it is simple to show that the input-output
relation of the system isUsing this basic relationship of the feedback system structure,
we can uncover some of the significant effects of feedback. 让我们考虑一下图16 .1简单
的反馈系统外形，r代表输入信号，c代表输出信号，e是误差，b是反馈信号。参数G和H被认为
是常量增益，通过简单的代数运算，我们可以知道系统输入与输出之间的关系是M=CR，利用反馈
系统结构的基本关系我们能够发现反馈的一些影响因素。.
Sensitivity considerations often play important role in the design, of control
systems. since all physical element have properties that change with environment and age,
we can not always consider the parameters of a control system to be completely stationary
over the entire operating life of the system. For instance，the winding resistance of
an electric motor changes as the temperature of the motor rises during operation. In
general, a good control sys- {?m should be very insensitive to these parameter variations
while still able to follow the command responsively灵敏度因素在控制系统设置中起着重
要的作用。由于所有的物理元素都有着随着环境与时间的改变而改变的特性，我们不能总认为一
个系统在整个使用过程中，它的参数是完全不变的。例如，电机的线阻绕阻随着电机运行时温度
的升高而改变，通常，一个良好的控制系统应该对这些参数的变化很不敏感，而仍能灵敏地跟踪
指令
In general, the sensitivity of the system gain of a feedback system to parameter
variations t depends on where the parameter is located. The reader may derive the
sensitivity of the system in Fig. 17. 1 due to the variation of
H.
通常，反馈系统的增
益对参数变化的灵敏度取决于参数所在位置
Effect of Feedback on External Disturbance or Noise
All physical control systems are subject to some types of extraneous signals or noise
during operation. Examples of these signals are thermal noise voltage in electronic
amplifiers 2nd brush or commutator noise in electric motors. 在运行过程中，所有的物理
控制系统都会受到某些类型的外来信号或噪音的影响。比如，在电子扩音器中产生的热噪声电压信
号和电动机中产生的电刷或换升器噪声信号
The effect of feedback on noise depends greatly on where the noise is introduced into the
system； no general conclusions can be made. However, in many situations，feedback can
reduce the effect of noise on system performance. 反馈对噪声的作用主要是看噪声是在什么
地方加入了系统中，一般设有通用的结论。但是，在许多情况下，反馈可以减少噪声对系统性能的
影响
In general, feedback also has effects on such performance characteristics as bandwidth,
impedance, transient response，and frequency response. 通常情况下，反馈也对诸如带宽、
阻抗、瞬态响应、频率响应等运行特性有影响。
Unit 18
The most recent class of control techniques to be used are collectively referred to as
adaptive control. Although the basic algorithms have been known for decades,they have not been
applied in many applications because they are calculation-intensive. 大多数最近控制技术的
分类通常是共同归类于自适应控制，尽管十几年前就已经知道算法他们还是没有被应用于许多场
合，因为他们都是计算内在的However, the lid- vent of special-purpose digital signal processor
(DSP) chips has brought renewed interest in adaptive-control techniques. The reason is that
DSP chips contain hardware that can implement adaptive algorithms directly, thus speeding up
calculations. 然而特殊目的数字信号处理器芯片的优点在自适应控制技术中引起了新的关注，由
于DSP芯片包含具有直接贯彻执行自适应算法的硬件，因此计算速度提高了。
The main purpose of adaptive control is to handle situations where loads. inertias, and
other forces acting on the system change drastically. 自适应控制的主要目的是为了处理像载
荷、惯性和其他力的状况，使得系统剧烈变化
A classic example of a system with changing parameters is a guided missile. Missile mass
drops as fuel burns, and it encounters differing friction at different altitudes. 一个典
型的变参数系统的例子是巡航导弹，导弹的重量会随着燃料的减少而减少，而且他在不同的高度
遭受着不同的摩擦。
Some system changes can be unpredictable, and ordinary closed-loop systems may not respond
properly when the system transfer function varies. Sometimes, these effects can be handled
by conventional linear-control techniques such as gain scheduling (feed-forward control). 一
些系统的变化是不可预知的，而且一般的闭环系统在系统的传递函数变化时可能不会正确的相应。
有时候这些影响可以通过常见的像增益调节、线性控制技术去处理Conservat ive design practices
may also enable some systems to remain stable even when subjected to parameter changes or
unanticipated disturbances. 守旧的设计实践也许也能够使一些系统在受到参数变化或者意外的
干扰依然保持稳定
The price paid for such stability is suboptimal performance, however. Response to changes
may be sluggish. Errors may fail to stay within satisfactory limits, or designs muss compensate
for loose error tolerances in other ways. 这些稳定性的价值是次优特性。然而，变化的响应
可能成为惰性的，误差就不能保持在满意的范围之内，或者设计通过其他方法补偿无限制的错误
公差
Adaptive control can help deliver both stability and good response. The approach changes
the control algorithm coefficients in real time to compensate tor variations in the environment
or in the system itself. In general the controller periodically monitors the system transfer
function and then modifies the control algorithm. 自适应控制可以很好地实现稳定性和良好的
响应。自适应控制系统可以通过改变自身的参数来适应环境的变化或者自身系统的变化。通常，控制器周期的监控系统的传递函数，然后修改控制算法， It does so by simultaneously laming about
the process while controlling its behavior. The goal is to make the controller robust to a point
where the performance of the complete system is as insensitive as possible:: modeling errors
and to changes in the environment.它是通过同时了解控制自己行为的过程来完成的，目的是加强
控制器的适应性，尽可能使整个系统的性能对建模误差和环境变化不敏感。
Even ordinary feedback-control systems are adaptive in a limited sense,in that they can
compensate for changes at their input that are within the system bandwidth. But these changes
are comparatively small. Such systems can become unstable for large input swings, or may simply
be unable to compensate for sufficiently large input Ranges. 实际上普通的反馈控制系统在一
定范围内具有自适应的，所以它们能够补偿在系统带宽范围内输入的变化。但是这些变化是非常小
的。这样的系统在输入摆幅很大时就会变得不稳定或者可能在更大输入摆幅时不能进行补偿。
There are two main approaches to adaptive feedback- control design ： model adaptive control
(MR AC) and self-tuning regulators (STRs). In MRAC. a reference model describes system
performance. 有两个主要的方法去设计自适应反馈系统：模型参考自适应控制和自矫正调节器。在
模型参考自适应控制中,参考模型描述系统特性.The adaptive controller is then designed to force
the system. or plant to behave like the reference model. Model output is compared to the actual
output and the difference is used to adjust feedback controller parameters. 自适应控制器
被设计促进系统或者设备模仿参考模型，模型的输出与实际的输出相比较，通过他们的不同来调整
反馈控制器参数。
Most work on MHAC has focused on the design of the adaptation mechanism. This Mechanism
most note the output error and determine how to adjust the controller coefficients .It
mast also remain stable under all conditions. 大多数模型参考自适应控制的运行都关注自
适应机械装置的设计。这种机械装置必须记录输出误差并且决定怎样调节控制器系数，它也必须在
所有条件下保持稳定。 One problem with the approach is that there is no general theoretical
method of designing an adapter. Thus, moot adapter functions are specially keyed to some
kind of end application. 这种方法会带来一个问题，就是没有通用的自适应机构设计的理论方
法。因此，大多数自适应机构功能是在某种条件下应用到某种场合上。
An advantage of MRAC is that it provides quick adaptations for defined inputs. A
disadvantage is that it has trouble adapting to unknown processes or arbitrary disturbances.
模型参考自适应控制器的优点是在定义的输入下提供快速的自适应性。缺点就是而不能适应未知过
程或者任意干扰。
Model-reference controllers have an adaptation mechanism. The comparable component
in self-tuning regulators is a tuning algorithm. A self-tuning regulator assumes a linear
model for the process being controlled (which is generally nonlinear). It uses a
feedback-controllaw that contains adjust able coefficients Self-tuning algorithms change
the coefficients..
These controllers typically contain an inner and an outer loop. The inner loop consists
of an ordinary feedback loop and the plant. This inner loop acts on the plant output in
conventional ways. The outer loop adjusts the controller parameters in the inner feedback
outer loop consists of a recursive parameter estimator combined with a control
design algorithm. 模型参考控制器有自适应机械装置，与之相比较的组成自矫正调节器是改变算
法。自矫正调节器是采取直线模型去控制过程。它用于通过调整系数的反馈控制法则。自矫正算法
改变了系数。
The recursive estimator monitors plant output and estimates plant dynamics by
providing parameter values in a model of the plant. These parameter estimates go to a
control -lawdesign algorithm that sends new coefficients to the conventional feedback
controller in the inner loop. 这些控制器经典控制内环和外环，内环是由一个普通的反馈环和
设备组成，这些内环通过传统的方法作用于设备的输出，外环调节在内反馈的控制器参数，外环是
由一个递归的与控制设计算法相关的参数估计量组成的。
The above description tends to be abstract because many different types of controllers
and schemes are used to estimate parameters. Among the most widely used controllers areP1D
state controllers* and deadbeat controllers. Recursive parameter estimation technique^
include stochastic approximation，least squares,extended Kalman filtering, and the
maximum likelihood method. 这些参数估计通过一个控制法则设计算法，将新的系数传给内环中
常见的反馈控制器。上文所描述的主要因为不同类型的控制器和设计常常用来估计参数，其中PID
稳定控制器和非周期控制器是使用最广泛的控制器，递归参数估计技术包含随机近似值，最小二乘
法，扩展卡尔曼滤波和最大似然法等方法。
Unit 19 Process Control (1)
Automatic control is an essential feature of large-scale continuous processes. Many
modern chemical plants are so complex that it would be impractical, unsafe and unprofitable
to run them manually. 自动化控制是大规模连续控制中一个必须的特征许多现代的化工设备非
常的复杂如果采用人工控制是不现实、不安全、不经济的
By its nature process control is concerned with the dynamic behaviour of systems. It
is no longer sufficient to make the steady-state assumption. Because of the extra
mathematical complexity involved in a quantitative treatment of control this section will,
instead， concentrate on general concepts rather than detailed analysis of specific
applications. 因此自然过程控制关心的是系统的动态运行状况，它没有足够的情形去作出假设
由于控制的定量数学分析特别复杂本节将注意力放在一般概念上而不考虑具体应用的细节分析
过程控制的目标。
Objectives of Process Control
Ensuring safe plant operation is one of the most important tasks of a control system.
This is achieved by monitoring process conditions and maintaining variables within safe
operating limits. Potentially dangerous situations are signalled by alarms and a plant
may even be shut down automatically. 确保设备安全运行时控制系统最重要的任务之一，这可
以通过监控过程条件和在安全运行范围内维持变量获得潜在的危险状况可以通过警告和设备可
能甚至自动关闭来发出信号
Safe operation is consistent with the economic objective of process control，which
is to operate the plant in such a way to minimize total costs..This involves maintaining
product quality, meeting production targets and making efficient use of utilities such
as steam, electricity, cooling water and compressed air. 安全运行与过程控制的经济目标
是一致的，即使工厂以总成本降至最低的方式运行这包括维持产品质量、完成产品目标和使用像
登记处理、电力、冷却液和压缩空气的实用工具来提高效率控制环。
The control loop
The functional layout of a process control loop is shown in Fig. 19. 1. A process operates
subject to some disturbances e. g. vb^ ‘process, may be a preheater and the，disturbance，
a varying feed temperature (Fig, 19. 2), 如图19.1所示是过程控制环的功能布局，过程
控制受到一些干扰，例如过程可能是一个预热器，“干扰”可能是已变化的温度（图19.2） We
identify a variable which needs to be controlled, e. g. the temperature of the stream
leaving the preheater. This quantity is measured by a suitable measuring device such
as a thermocouple, The output horn the measuring device is passed to a controller where
it is compared with the setpoint for the controlled variable. A control signal is
generated and activates the final control element. 我们识别一个需要被控制的变量，例
如水蒸气离开预热器时的温度，这个量是通过像热电偶这类测量装置被测量的，测量装置的输出传递给控制器，为了控制的变量控制器和定位点相比较产生控制信号并激活最终的控制元
件usually a control valve. The control valve changes the value of the manipulated
variable、e. g. the flowrate of the hot stream to the heat exchanger. A more complex
process will typically have a number of control loops each controlling different process
variables. The loop described above is an example of a feedback control loop. 通常
是控制阀，控制阀改变操作变量阀，例如热蒸汽的流速改变热交换，更复杂的过程一般会有大
量的控制环，每个环控制不同的控制变量，上面对环的描述是一个反馈控制环的例子其他类型
的控制策略也可以Other types of control strategy are possible but the feedback
controller is the simplest and most widely used. The elements of the c6ntrol loop will
now be examined in turn. 不过反馈控制器是最简单的并且被广泛使用。控制环的元件现在将
会被逐一地测试。
Measuring Devices
The controlled variable in a process must be amenable to measurement—either directly
or indirectly. The most important types of variables controlled in chemical processes are
flow rate, temperature, pressure, composition and liquid level. 在过程中的控制变量必须
能够被直接或者间接地被测量，在化工过程中最重要的变量控制类型是流量，温度，压力，合成和液位。
? The characteristic required of a measuring device for process control may differ from
those of general purpose instruments,It is necessary to transmit a signal
representing the measurement from the measuring element to the controller一at one
time this was done pneumatically but now an electrical or optical signal would be
used. 为了达到过程控制的目的，测量装置的特征需求可能不同于那些普通用处的仪器，必
须来自测量元件，代表测量结果的信号传送到控制器中—有一段时间这一过程是由气动方式
实现的，但现在是用光信号或电信号进行传送的For example, a mercury-in- glass
thermometer may provide a sufficiently accurate temperature measurement but it is
difficult to convert it into an electrical signal. By contrast, the output of a
thermocouple is naturally an electrical signal and hence this device is a more
suitable choice for control a applications. 例如，水银柱式热敏电阻可以提供非常精
确温度测量。但是它很难转换成电信号，热电偶的输出本来就一个电信号，因此这个装置更
适合作为控制应用的选择。 Another important characteristic is the dynamic response
of the measuring system. For stable and effective control it is important to minimize
the time lag between, a variable moving off its setpoint and corrective action being
taken. A measuring element must therefore respond quickly to changes—this is not
always easy to achieve. 另一个重要的特征就是测量系统的动态响应，为了稳定和高效的
控制，重要的是在变量偏离定位点和改正被采取的行动之间最小的时间滞后。一个测量元件
必须对于变化能够迅速响应，这通常是不容易获得的For example, a thermocouple directly
immersed in a flow will respond more quickly than one welded to the outside of a
pipe but it may be subject to corrosion. The literature on measuring systems is
extensive. Table 19.1 lists some of the common measuring techniques used. 例如，
一个电偶被浸入到流体里将比焊在管外响应更迅速，但这可能被腐蚀，关于测量系统的书非
常多，表19.1列出一些普遍测量技术的使用。
UNIT 20
the role of measurement is to provide information on system status which,in a
mechatronic system, is used to control the operation of the system. this function is
performed by the measurement modules which incorporate the necessary sensors and
transducers together with any local signal processing. 在机电一体化系统中，测量的角色
是提供用于控制系统运行的系统状态信息。这个功能是通过必要的传感器和转换器结合局部信号处
理而形成的测量组件来完成的。
measurement technology is not a new science but can be traced back to origins in
trade,where the need to quantify,on a basis which was both repeatable and
representative,the nature of goods on offer led to the introduction of standards for
measures such as volume and weight. with the growth in science and technology as exemplified
by the renaissance, more and specific measuring instruments evolved to support the growing
interest in and investigation of the physical world. 测量技术不是一门新的光科学，他可
以追溯到交易的起源，在可重复性和典型性基础上，由于量化的需要，出售商品的自然特性导致了
像体积、重量等测量标准的引入。随着以文艺复兴时期为代表的科技发展，越来越多的专门的测量
工具逐步发展以支持我们队物理世界日益增加的关注和研究。
with the advent of the industrial revolution, instrumentation and measurement science
began to be applied to manufacturing. the early instruments were analogue in nature and
provided information about the basic physical parameters concerned with the operation
of the process. 随着工业革命的出现，工具盒测量科学开始应用与制造业。早期的工具是仿自然的，只提供与加工过程有关的物理参数的信息。feedback was achieved by the operator who read
the instruments and then made the necessary adjustments to maintain the process within
the required bounds. 反馈是通过操作人员读取仪器上的读数，然后做必要的调整，以把工艺过
程维持在所要求的范围之内来达到的。
the next step forward came with the introduction of the steam engine and automatic
feedback control mechanisms such as the watt governor for speed control. following this
lead, instrumentation gradually became more integrated with the process, providing
feedback information to a controller which then regulated the system behavior with minimum
of manual intervention. 向前推进的下一阶段是伴随蒸汽机以及瓦特调速器等自动反馈机械装置
的引入到来的。随之而来，仪器产业与过程结合越来越紧密，它提供反馈信息给控制器而使系统操
作依赖较少的人工干预。
by the late 1960s the advantages of discrete control had been recognized and production
processes were often controlled by relay based relay controllers, though
complex in configuration and layout, were relatively unsophisticated and incapable of
handling complex information. 到1960年代末，离散控制的优势被认知，生产工艺常由继电器
系统控制，然而，这种伺服控制在装配和布局上很繁琐，相对不长久且不能出来复杂信息the
performance requirements of their associated sensors and transducers were correspondingly
restricted to the supply of simple data at a level capable of being utilized by the
controllers. 与之相关的传感器和转换器的性能要求也相应被限定在提供能被控制体利用范围内
的简单数据。
there conditions were largely maintained with the introduction of computer monitored,
as opposed to controlled, systems in which the computer was used primarily in a supervisory
role as a central machine receiving information sequentially from a number of radially
connected outstations. with the advent of minicomputers such as the DEC PDP series,
computer controlled systems increased in both number and scope, though they were limited
in application by both processing power and cost. 这种状况由于与控制相反的引入较大范围
内得以保持，该系统中计算机主要作为中央机承担监管角色，不断从一系列线性相关的外部接收信
息。随着DEC，PDP等系列微型计算机的出现，计算机控制系统的数量更大范围更广，尽管由于处
理能力和成本等因素使得他们的应用受到限制。 more recently, sophisticated microprocessor
systems have resulted in the complex interconnected designs that are now found in both
products and manufacturing processes. 最近，复杂微处理器以可编程的逻辑控制和分布式嵌入
式的微处理机系统激起了错综复杂的内部联系设计，这些在产品和制造工艺中都能实习。
the growth in microelectronics and computing technologies from the mid 1970s that made
available low cost processing prower has resulted in a parallel growth in the demand for
information about system conditions. 从19世纪开始随着微电子技术和计算机技术的发展，使
低成本操作成为可能，也导致了信息系统状况的平行增长。 in many cases this increased demand
could not be met by existing sensors and transducers and resulted in the development of
a range of advanced sensors and transducers, often incorporating local processing power,
either integral with the sensing element on the same silicon slice or in the form of a
single chip microprocessor.在很多场合下，现有传感器和转换器不能满足这种增长需求，而引
起了一系列高级传感器和转换器的发展。他们通常配合局部处理能力，可能用于硅片上构成传感器
元件或者以单片机形式存在。
sensors, transducers and measurement传感器、转换器和测量
in any measurement system, sensors and transducers are used to provide information
about system conditions. unfortunately, the usage of the terms sensor and transducer is
complicated by the variety of different meanings adopted internationally, including in
some instances an apparent interchangeability. for the purpose of this book the following
definitions are adopted: 在许多测量系统中，传感器和转换器都被用于提供系统状态信息。不
幸的是，条件传感器和转换器的使用被国际上五花八门的应用形式复杂化了，包括在一些场合下明
显的可互换能力，处于这种目的，本书引入一下概念。
sensors that part of the measurement system that responds to the particular physical
parameter to be measured.传感器是测量系统的组成部分,能对特定的物理参数的测量。
Transducer That component of the system that transfers information in the form of energy
from one part of the system to another, including in some cases changing the form of energy
containing the information. 转换器系统的这个组成部分以能量的形式将信息从系统的一部分
传递到另一部分，包括在一些情况下改变带有信息的能量的形式
In addition to a sensortransducer, a measurement may include a pre-processing stage and
a post-processing stage, as shown in Fig. 20. 除了传感器、转换器以外，一个测试系统还可
能包括前处理单元和后处理单元。如图20.1所示The pre-processing stage serves to
characterize the information in the incoming signal before presentation to the sensing
element. this then detects and responds to the physical stimulus at its input and provides
the input to the transducers. The output signal from the transducer is then operated on
by the post-processing stage to produce the final output The relationship between these
stages is illustrated by the optical encoder used for speed measurement shown in Fig. ，
前处理单元在它把信息传给传感器之前描述输入信号的信息特征，然后检测并对其输入做出物理模
拟响应，将输入信号传送给转换器。从转换器传出的信号被后处理单元处理后生成最终的输出信号。
这些单元之间的关系可以通过用于速度测量的光学编码器来描述。 20. 2. Here, the light from
the sources is pre-processed by the slotted disc to produce a series of pulses. These light
pulses received by the transducer which converts the signal into a series of electrical
pulses. the post-processing stage then counts the number of pulses occurring in a defined
time interval to determine the speed of rotation of the shaft carrying the encoder. 如图20.2所示，这里，从光源发出的光被标码的圆盘进行前处理，产生一系列的脉冲，后处理单元通
过计算在特定的时间间隔内的脉冲数来确定带有编码器的轴的转速。
As has been stated the physical basis for the transmission of information by a
transducer is that of energy transfer. This concept has been developed by Middelhoek to
identify six signal energy domains for the transfer of domains are as
follows： radiant,mechanical, thermal，electrical, magnetic and chemical. 如上所述， 转换器传递信息的物理基础是能量传递，这个概念是由MIDDELHOEK发明的，用以确定传递信息的
六个信息能量领域，这些领域如下：光的、机械的、热的、电的、磁的和化学的。
Of these, the electrical output domain is the most significant in a mechatronics
context because of its information handling capability, and transducer outputs in other
domains may well be further processed to transfer the information into the electrical
domain. 在这些领域中，电输出领域在机电一体化领域中是最显着的，这是因为它的信息处理能力，
并且转换器在其他领域的输出也被进一步处理成电信号来传递信息。
Unit21
sensors are devices that provide an interface between electronic equipment and the
physical help electronic to 传感器
是在电设备和物理世界之间提供接口的装置、他们帮助电去“看”“听”“闻”“尝”和“触”，
他们和真实世界相连。in their interface with the real world, sensors typically convert
nonelectrical physical or chemical quantities into electrical signals. this chapter
provides a brief introduction to the world of sensors. 传感器将非电的物理和化学信号转
换成电信号，这章简要地介绍传感器世界入门。
introduction
microsensors have become an essential element of process control and analytical
measurement systems,finding countless applications in, for example,industrial
monitoring,factory automation the automotive industry,transportation,
telecommunications,computers and robotics,environmental monitoring,health care, and
agriculture; 微传感器已经成为过程控制和一些不重要测量系统中不可缺少的元件，例如在产业
监控，工厂自动化，自动化工业，交通运输，电信通讯，计算机和机器人，环境监控，医疗保健和
农业中in other words, in almost all spheres of our life. the main driving force behind
this process comes from the evolution in the signal processing. with the development of
microprocessors and application-specific integrated circuits, signal processing has
because cheap, accurate, and reliable-and it increased the intelligence of electronic
equip ment在其他方面，甚至我们生活的范围。主要的驱动力是在来自于信号处理衍化的过程之后
的，随着微型计算机和特定用途的集成电路的发展，信号处理变得廉价、精确而且可靠。他提高了
电子设备的能力 .in the early 1980s a comparison in performanceprice ratio between
microprocessors and sensors showed that sensors were behind. this stimulated research in
the sensor area, and soon the race was on to develop sensor technology and new devices.
new products and companies have emerged from this effort, simulating further advances of
microprocessors. application of sensors brings new dimensions to products in the from
of convenience, energy savings, and safety. 在19世纪80年代早期，在微处理器和传感器之
间性价比可知，传感器是落后的，这就刺激了传感器领域的研究，很快竞赛发展了传感器技术和新
的设备，新产品和公司也纷纷出现，很大程度上刺激了微传感器的发展，传感器的应用在产品的便
利，能源节约和安全方面带来了新的规模toda y, we are witnessing an explosion of sensor
applications. sensors can be found in many products, such as microwave and gas ovens,
refrigerators,dishwashers,dryers,carpet cleaners, air conditioners, tape recorders, tv
and stereo sets, compact and videodisc players. and this is just a beginning今天我们
正目击着传感器应用的激增，传感器已经应用到很多产品上，像微波燃气烤箱、挖煤机，烘干机。
地毯清洗机，空调，磁带录音机，电视，立体音响，VCD，播放机，而且这仅仅是一个开始.
sensor classification
sensing the real world requires dealing with physical and chemical quantities that are
diverse in nature. form the measurement point of view, all physical and chemical
quantities(measurands)can be divide into six signal domains传感器的分类感觉真实世界需
要处理在自然界中不同的物理量和化学量，以测试的角度看，所有的物理量和化学量都可分为六种
信号领域
1,the thermal signal domain: the most common signals are temperature, heat, and heat flow.
1热信号领域：最普遍的信号是温度、热量和热流量
2,the mechanical signal domain: the most common signals are force, pressure, velocity,
acceleration,and position. 力学信号领域：最普遍的信号是力、压力、速度、加速度和位置
3,the chemical signal domain: the signals are the internal quantities of the matter such
as concentration of a certain material, composition, or reaction rate. 化学信号领域：
信号是向某种单一物质的浓度组成或反应速度这些内在物质的量
4,the magnetic signal domain: the most common signals are magnetic field intensity, flux
density, and magnetization磁信号领域：最普遍的信号是磁场强度、磁通量和磁化强度
5,the radiant signal domain: the signals are quantities of the electromagnetic waves such
as intensity, wavelength,polarization, and phase. 光学领域：信号是电磁波量像强度、波长、
偏振效应和相位6电信号领域：最普遍的信号是电压、电流和电荷
6,the electrical signal domain: the most common signals are voltage, current, and charge.
6电信号领域：最普遍的信号是电压、电流和电荷
as mentioned,sensors convert nonelectrical physical or chemical quantities into
electrical signals. it should be also noted that the principle of operation of a particular
sensor is dependent on the type of physical quantity it is to sense. therefore, it is no
surprise that a general classification of sensors follows the classification of physical
quantities. accordingly, sensors are classified as thermal, mechanical, chemical,
magnetic, and radiant. 如上可知传感器是将非电的物理或化学量转换成电信号，应该注意某种
传感器的操作原则是依靠被设计成传感物理量的分类，因此传感器的分类是随着物理量的分类就不
惊奇了。因此传感器分类成热的、力的、化学的、磁的和光的
there is also a classification of sensors based on whether they use an auxiliary energy
source or not. sensors that generate an electrical output signal without an auxiliary
energy source are called self-generating or passive. an example of this type of sensors
is a thermocouple. sensors that generate an electrical output signal with the help of an
auxiliary energy source are called modulating or active. 也有根据传感器是否作为辅助能
源来分类的，没有辅助能源的电信号输出传感器称为自激励传感器或者被动传感器，这个传感器的
类型可以是热电偶，如果有辅助能源的电信号输出传感称为调制获得主动。
Unit23whatis“Mechatronics”
“Mech atronics”
isatermcoinedbytheJapanesetodescribet heintegrationofmechanicalandelectronicengineerinceptmayseemtobeanythingbutnew,sincewecanlookarou ndusandseeamyriadofproductsth
ronics,however,sp eciallyreferst
oamultidisciplined,esen
tsthe nextgenerationofmachines,robots,andsmartmechanisms necessaryforcarryingoutworkina
varietyofenviron ments-primarily,factoryautomation,officeautomation ,andhomeautomationa
sshownin译文：“机电一体化“是一个有日本人描述机械和电子集成的合成术语。这个概念看上去
不再新颖，自从我们能观察四周和看到无数那些利用机械和电子学科的产品。机电一体化，然而，
特别是涉及到许多学科，结合方法去生产和制造系统设计。他代表下一代机械，机器人和灵巧机构
必须执行工作在各种环境，首要的，工厂自动化，办公自动化，家庭自动化如图23.1所示。
Bybothimplicationandapplication,mec hatronicsrepresentsanewlevelofintegrationforadvanc
entistoforceamultidisciplinaryapproachtot
h esesystchatron
icapproachiscurrentlyspeedingupt healready-rapidJapaneseprocessfortransformingideas int
oproducts.
译文：通过两个含义和应用，机电一体化代表了一个集成先进制造技术和过程的新水平。目的是将
一个多学科的方法用到这些系统以及反复强调过程的作用的理解和控制。这个机械电子的方法目前
加快了日本人已经将观念转化到产品的快速进程。
Current ly,mechatronicsdescribestheJapanesepracticeofusing fullyintegratedteamsofproduc
tdesigners,manufac turing,purchasing,andmarketingpersonnelactingincon certwitheachother
todesignboththeproductandthem anufacturingsystem.
译文：目前，机电一体化阐述了日本人使用充分结合的队伍的实践，这一队伍包括产品设计者、制
造人员、采购人员，他们相互一致行动，既设计产品又设计制造系统。
TheJapaneserecognizedthatthefutureinproduct ioninnovationwouldbelongtothosewholearnedh
aliz ed,inparticula
r,thattheneedforthisoptimization wouldbemostintenseinapplicationofadvancedmanufactu rin
gandproductionsystemswhereartificialintelli gence,expertsystems,smartrobots,andadvance
dman ufacturingtechnologysystemswouldcreatethenextgener ationoftoolstobeusedinthefactor
yofthefuture. 日本人意识到生产创新的未来会属于那些掌握了怎样使电子和机械系统结合得最优的人。他们认识
到在用人工智能，专家系统，灵巧机器和先进制造技术来制造出将来工厂要使用到的新一代工具的
制造和生产系统，尤其需要这种机电一体化的结合。
Fromtheverybeginningsofre cordedtime,mechanicalsystemshavefoundtheirwayintoe veryaspect
plestmechanisms,suchasgears,pulleys, springs,andwheels,haveprovided
ctronicstechnolo gy,ontheotherhand,iscompletelytwentieth- cen
tury,allofitcreatedwithinthepast75years. 自有时间记录以来，机械系统出现在了我们社会的每一个方向。我们最简单的机构，例如：齿轮、
滑轮、弹簧、和轮子，组成了人类工具的基础。在另一方面，我们的电子技术在过去的75年里创
造了整个二十世纪。
Untilnow,theelectronicswereincludedtoenh ancemechanicalsystems’
performance,adneverbeena nymasterpl
ast,ce
ntly,however,becauseoftheo verwhelmingadvancesintheworldofelectronicsanditsca pabilityt
ophysicallysimplifymechanicalconfigur ations,thetechnicalcommunitybegantoreassessthemarriagebetweenthesetwodisciplines.
直到现在，电子产品被用于提高机械系统的性能，而且强调保留在机械产品中。在怎样做一体化方
面从来没有总体规划，在过去，它是在一件一件的基础上制作出来的。然而，近年来，由于电子世
界重要的先进性和它对机械外形的物理简化能力，技术界开始重新评估这两个学科之间的结合。
Themostobvioustrend inthedirectionofmechatronicinnovationcanbeobserved intheautomobilei
asatimewhenacarwasprimarilyame chanicalmarvelwithafewelectronicappendage
s. 在机电一体化改革方向最明显的趋势可以在汽车行业观察到。曾经有一段时间，汽车主要是一个有
几个电子附件组成的机械奇迹。
Firstcamethestartermotor,andthen thegenerator,eachmaikingtheoriginalproductabitbett ert
mesolid-stateelectronics,andsuddenlythemech anicalmarvelbecameane
’
smacineiscontrolledb ymicroprocessors,builtbyrobots,andfault-analyzedby acomputerconnec
tedtoits
“externalieterfacec onnector”.Automo-tivemechanicalengineersarenolonge rthemastersoft
heircreations.首先是起动机电机，然后是发生器，每个制造的原产品都比以前更好。然后是固体
电子学，突然变成了一个电气机械的奇迹。今天的机器是由微处理器控制，建立了机器人，和故障
分析的计算机连接到它的“外部接口连接器”。汽车的机械工程师不再是他们的创作大师。
Theprocessthatdescribestheevolutiono ftheautomobileissomewhattypicalofotherproductsino onicshasrepeatedlyimprovedtheperformanceofmecha nicalsystems,butthatin
tistheessenceofmechatron ics-thepre
plannedapplicationof,mechanicalandel ectronicstechnologytocreateanoptimumproduct.
这个过程,描述了在我们的社会中汽车的进化过程中有些典型的其他产品。电子一再提高机械系统
的性能, 但是,创新比设计更有可能。这是机电一体化应用的本质，机械和电子技术来创造一个最佳
的产品。 mentofcommercereportentitled“JTECHPanelreporton MechatronicsinJapan”
aneseresearchanddevelopmen ttrendsinspecificareasofmechatronicstechn
foraf ewareas,thetechnologynecessarytoaccomplishthedevel opmentofthenextgen
erationofsystemsembodyingthe principlesofmechatronicsisfullywithinthetechnologi calreac
hoftheJapanese.
最近美国商务部的报告题为“JTECH小组报告日本的机电一体化“相比美国和日本在特定领域的机
电一体化技术的研究和发展趋势。除了少数地区,开发下一代系统需要创新技术体现机电一体化的
原则上是必须在其技术达到的日本的程度
C omparisonsweremadeinthreecategories:basicresearch, advanceddevelopment,，
formachinevisionandsoftwa re,Japanesebasicresearchwasco
mparabletotheUnit edStates,withtheJapaneseclosinginfastonmachinevisi onsystemtechnology
..Japaneseartificialintellig enceresearchisfallingbehind,primarilybecausetheJap anesedo
notconsideritanessentialingredientofthe irfuturesystems,theyappearcapableofclosingeven
thatgap,dvanceddevelopmentandproductimplementation areas,Japanisequal
toorbetterthantheUnitedState s,andiscontinuingtopullaheadatthistime.
特别是在三个方面:基础研究、先进的开发,和产品实现。除了机器视觉和软件,日本的基本研究与
美国的相提并论, 日本的机器视觉系统技术开发的较快..日本的人工智能研究落后,主要是因为日
本不考虑这是他们的未来的一个重要组成部分,他们表现出的系统关闭甚至差距,如果需要。在先进
的开发和产品实现地区、日本接近或优于美国,将领先在一段时间
TheDepartmentofCommercerepor tconcludedthatJapanismaintainingitspositionandisin somecas
erogressinmecha
tronicsisimportantbe causeitaddressestheverymeansforthenextgenerationof data-drivenadva
,theDepartmentofCommercereportc oncludestha
tthishascreatedaregenerativeeffecto nJapan’smanufacturingindustries.
Toclosethegap ,ceptthefactthatmech
anicalsystemsoptimallycoup ledwithelectronicscomponentswillbethewaveofthefutu re,thenwe
mustalsounderstandthattherippleeffect willbefeltallthewaybacktotheuniversity,wherewenowkeepthetwodisciplinesofmechanicsandelectronicss eparatedandallowthemtomeetonlyinoccas
riculamus tbecreatedforanewhybridengineer---amechatronicseencanbeassuredthatfuturegenerationsofproductdesi gnersandmanufacturingen
gineerswillfullyseekexc ellenceinthesenewtechniques.
商务部报告结束后日本保持它的地位，和在某些情况下美国在机电一体化技术的应用程序中获得地
位。他们在机电一体化方面的进展是重要的，因为它涉及的数据驱动的下一代是手段先进的设计和
制造技术。事实上，商务部报告的结论造成了对日本制造业再生的影响。
为了减小差距，我们需要进一步研究而不仅仅是制造新的机器，如果我们接受机械系统优化和电子
元件将是未来的趋势，那么我们就不得不明白，它在大学中的的连锁反应，大学里，现在我们将机
械学科和电子学科分离，而仅仅在偶然的会议上才会碰面，所以作为一个新的复合工程师，必须建
立一门课程——机电一体化工程师，只有这样，我们才能够确保将来的产品设计师和制造工程师能够利用好这些新技术。
Weneedtorethinkourpresent-dayappr oachofseparatingourengineeringstaffsbothfromeachot he
togetherandcommunicatingindividualknowledgew illc
minteractionwillbethekeytooptimumdesignsan
dnewproductdevelopment.
我们需要重新思考我们今天的做法，我们的工程技术人员都从对方从生产工程师分离。个人知识的
共同生活和沟通，将创建一个新的产品协同效应。最大程度的互动将是最佳开发的关键
changethewaywedesign
ionth atfullyimplementstheru
dimentsofmechatronicsand vigorouslypursuesitwillleadthewordtoanewgeneration oftechnolog
yinnovationwithallitsprofoundimplic ations.
机电仪一体化的定义是更加重大颠倒的。它将改变我们设计并且引起高科技产品的下一代的方式。
国家，充分实现了机电一体化技术的基本原理和大力追求它将带领这个词对一代新的技术创新具有
其深远的影响。

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