机械工程专业英语 施平 没翻译课文补充
戴南高级中学-关系网站
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4、工程机械概述
As we look around
us we see a world full of “things”: machines,
devices, tools;
things that we have
designed, built, and used; things made of wood,
metals, ceramics,
and plastics. We know
from experience that some things are better than
others; they
last longer, cost less, are
quieter, look better, or are easier to use.
正如我们环顾四周我们看到世界的“东西”机器全设备工具;事情我们已经设
计建造和使用;木材金属
陶瓷制成的东西和塑料。我们从经验知道有些事情是比
别人做得更好他们去年更长成本更低更安静看起来更好或者更容易使用。理想的
情况.
Ideally, however, every such
item has been designed according to some set of
“functional requirements” as perceived by
the designers — that is, it has been
designed so as to answer the question,
“Exactly what function should it perform?”
In the world of engineering, the major
function frequently is to support some type
of loading due to weight, inertia, pressure,
etc.
但是每个这样的项目已按设计一些“功能要求”由设计者认为也就是说
它的设
计以回答这个问题“究竟是什么职能应是执行在工程世界”频繁的主要功能是如此
的
支持由于一些装载重量惯性压力式
From the
beams in our homes to the wings of an airplane,
there must be an
appropriate melding of
materials, dimensions, and fastenings to produce
structures
that will perform their
functions reliably for a reasonable cost over a
reasonable
.
.
lifetime.
从我们家中的光束飞机的一个机翼等必须对产品的材料尺寸适当的融合
件生产结构将执行一个较合理的成本合理的一生中其职能可靠。
In practice, engineering mechanics
methods are used in two quite different ways:
(1) The development of any new device
requires an interactive, iterative
consideration of form, size, materials, loads,
durability, safety, and cost.
(2) When a
device fails (unexpectedly) it is often necessary
to carry out a study
to pinpoint the
cause of failure and to identify potential
corrective measures. Our
best designs
often evolve through a successive elimination of
weak points.
在实践中工程力学方法用于在两个完全不同的方式
和紧固
1.任何新设备的发展需要一个互动形式尺寸材料载荷耐久性安全性和cost.
2.迭代审议。当一个设备出现故障往往是要进行一项研究以查明故障原因并找出
潜在的纠正措施。我们最优秀的设计往往演变的薄弱环节通过逐步消除。
To many engineers, both of the above
processes can prove to be absolutely
fascinating and enjoyable, not to mention (at
times) lucrative.
对许多工程师上述过程都可以被证明是绝对精彩和愉快的更不用提有利可图。
In any “real” problem there is never
sufficient good, useful information; we
seldom know the actual loads and operating
conditions with any precision, and the
.
.
analyses are seldom exact.
While our mathematics may be precise, the overall
analysis
is generally only approximate,
and different skilled people can obtain different
solutions. In the study of engineering
mechanics, most of the problems will be
sufficiently “idealized” to permit unique
solutions, but it should be clear that
the “real world” is far less idealized, and
that you usually will have to perform
some idealization in order to obtain a
solution.
在任何“真正”的问题从来就没有足够好的有用的信息我们很少知道实际的载荷和
精确操作的任何条件准确的分析很少。虽然我们可以精确的数学综合分析一般只是近
似不同技能的人可以得到不同的解决方案。在工程力学研究中大多数问题都将得到充分
的“理想化”允许独特的解决方案但应该清楚“现实世界”远不如理想而且你通常会
在命令必须执行一些理想化获得一个解决方案。
The
technical areas we will consider are frequently
called “statics” and
“strength of
materials,” “statics” referring to the study of
forces acting on
stationary devices, and
“strength of materials” referring to the effects
of those
forces on the structure
(deformations, load limits, etc.).
在技术领域中我们将考虑的是通常称为“静”与“材料力学”“静”指的是对固定设
备作用力学风和“材料力学”指的是这些部队在结构上的影响。
While a great many devices are not, in fact,
static, the methods developed here
are
perfectly applicable to dynamic situations if the
extra loadings associated with
the
dynamics are taken into account (we shall briefly
mention how this is done).
.
.
static
尽管许多设备都没有事实上静态的这里开发的方法是完全适用于动态的情况如果
与动态相关联的额外负荷考虑。.
Whenever
the dynamic forces are small relative to the
static loadings, the system
is usually
considered to be
每当动态势力相对较小的静态负荷系统通常被认为是静态的。
In engineering mechanics, we will appreciate
the various types of approximations
that
are inherent in any real problem:
Primarily, we will be discussing things which
are in “equilibrium,” i.e., not
accelerating. However, if we look closely
enough, everything is accelerating. We
will consider many structural members to be
“weightless” — but they never are.
We
will deal with forces that act at a “point” — but
all forces act over an area.
We will
consider some parts to be “rigid” — but all bodies
will deform under load.
在工程力学我们赞赏逼近了在任何类型的固有的各种现实问题
首先我们将要讨论的事情这是在“均衡”即没有加速。但是如果我们仔细观察
的话一切都正在加速。我们会考虑很多构件是“失重”但是他们从来没有的。我们将按
照部队的这种行为在一个“点”但所有力量在一个区域的行为。我们会考虑的某些部分
“刚
.
.
性”但所有机构将在负荷下变形。
We will make many assumptions that
clearly are false. But these assumptions
should always render the problem easier, more
tractable. You will discover that the
goal is to make as many simplifying
assumptions as possible without seriously
degrading the result.
我们会作出这样的假设显然是错误的。但是这些假设应始终呈现的问题更容易更容
易处理。你会发现他们的目标是使尽可能多的简化假设没有严重退化的结果。
Generally there is no clear method to
determine how completely, or how precisely,
to treat a problem: If our analysis is too
simple, we may not get a pertinent answer;
if our analysis is too detailed, we may not be
able to obtain any answer. It is usually
preferable to start with a relatively simple
analysis and then add more detail as
required to obtain a practical solution.
一般来说没有明确的方法来确定如何彻底或如何精确地说对待一个问题如果我
们的分析过于简单我们可能无法获得相关的答案如果我们的分析过于详细我们可能
无
法获得任何答案。它通常是最好先从相对简单的分析然后添加更多的细节因为需要得到
实际的解决办法。
During the
past two decades, there has been a tremendous
growth in the
.
.
availability of computerized methods for
solving problems that previously were
beyond solution because the time required to
solve them would have been prohibitive.
At the same time the cost of computer
capability and use has decreased by orders
of magnitude. We are experiencing an influx of
“personal computers” on campus,
in the
home, and in business.
在过去的二十年来一直在为解决以往无法解决的问题进行电脑化方法的途径巨大增
长因为所需的时间来解决这些问题将被禁止。在同一时间内计算机能力和使用成本下降
了几个数量级。我们正经历一个“个人电脑”校园涌入在家里和商业活动中。
26、车床
The general characteristics of
the machine tools used in cutting operations are
reviewed in
this text. The equipment can
be classified in different categories depending on
their function
and the accessories
involved. The major categories are described
below.
在切割操作中使用的机床的一般特征在这篇文章进行阐述。依据功能和所包含的配
件设备可分为不同类别。主要类别如下所述。
Lathes Lathes
are generally considered to be the oldest machine
tools and were developed
in the basic
operations carried out on a lathe are turning,
boring, and facing.
车床
车床通常被认为是最古老的机床并在1750s产生.车床上进行基本操作有车削
镗和端面车削。
.
.
The basic components of the most common lathe(
engine lathe ) are the bed, headstock,
tailstock, and carriage. One end of the
workpiece is clamped in a chuck that is mounted on
the spindle, the spindle rotates in the
headstock. The other end of the workpiece is
supported
by the tailstock. The
headstock contains the drive gears for the spindle
speeds, and through
suitable gearing and
the feed rod, drives the carriage and cross slide
assembly. The carriage
provides motion
parallel to the axis of rotation, and the cross
slide provides motion normal
to it. A
cutting tool, attached to a tool post and to the
carriage, removes material by traveling
along the bed. The cutting operation is
performed at a certain desired peripheral speed of
the workpiece, feed rate, and depth of
cut
最常见的车床普通车床的基本组成部分是床身床头尾座和.托架。工件的一端
是被一个安装在主轴的夹头夹紧主轴在床头旋转。工件的另一端是由尾座支撑。床头包含
主轴转速传动齿轮并通过适当的齿轮和进给杆驱动车架使滑动装配滑动。托架提供运
动平行旋转轴横滑板提供了正常的运动。切削刀具连接到一个刀架和托架沿床消除材
料。切割操作是按工件所需的一定的外设速度进给速度切削深度运行。
A
further development is the automatic lathe. The
movements and controls
are actuated by
various mechanical means, such as cams and
numerical and computer
control, thus
reducing labor or requiring less skilled labor.
进一步发展的是自动车床。通过各种机械手段运动和控制更加精确。如凸轮和数控
.
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和计算机控制从而减轻了工人的劳动或要求不太熟练的劳动力。
Turret lathes (developed in the
1850s)carry out multiple cutting operations,
such as turning, boring, drilling, thread
cutting, and facing. Various cutting tools,
usually up to six are installed on a turret.
The operation is quite versatile. It
may
be operated by hand or automatically and, once set
up properly, it does not
require skilled
labor. There are a great variety of turret lathes
available for
different purposes.
转塔车床在19世纪50年代开发的能够进行了多种切割操作如车削镗钻
线切割端面车削。各种切削工具通常在最多六个炮塔上安装。操作相当灵活。它可能是
手工操作或自动一旦正确安装它并不需要熟练的劳动力。有种类繁多的炮塔车床可用于
不同的目的
Screw machines (the first
screw lathe was developed in the 1770s)are
designed for high
production rate
machining of screws and similar parts. All the
operations are performed
automatically
with tools attached to a special turret. The bar
stock is fed automatically after each
screw has been machined to a finished product.
These machines may be equipped with single or
multiple spindles to reduce the cycle
time per piece.
螺杆机在18世纪70年代开发了第一个螺丝车床是专为高产率自动化生产螺钉
和类似部件的设计的。所有的操作都由连接到一个特殊的炮塔的工具自动执行。每个螺丝
加
工成成品后棒料自动送入。这些机器可能会配有单个或多个主轴
.
.
Milling Machines
These are among the most versatile and useful
machine tools because
they are capable
of performing a variety of cutting operations.
There is a large selection of milling
machines (developed in the 1860s)available
with numerous features.
The basic types
are outlined -and-column type milling machines
are the most
common and are used for
general-purpose machining. The spindle, to which
the milling cutter is
attached, may be
horizontal (for slab milling), or vertical (for
face milling).
铣床铣床是最通用和最有用的工具机因为它们能够执行各种切割操作。有大量的
提供众多特性的铣床可供选择在19世纪60年代开发的。基本类型概述如下。
升降台式铣床是最常见的用于一般用途的加工。连接铣刀的主轴可水平板坯铣
削或垂直面铣。
Bed-type milling machines
have the table mounted on a bed (replacing the
knee) and can
move only in the
longitudinal direction. These machines are simple
and rigidly constructed and
are used for
high-quantity production. The spindles may be
horizontal or vertical and can be of
duplex or triplex types (that is, with two or
three spindles for simultaneous machining of two
or
three surfaces on a part). Other
types of milling machines are also available,
such as the
planer type for heavy work
and machines for special purposes
床身式铣床上安装一个平台只可以在纵向方向移动。这些机器很简单严格装配并
用于高量产。主轴可水平或垂直可以双工或三工类型即有两个或三个主轴同时加工两
个或三个部分表面。其他类型的铣削机也可用如用于繁重的工作的龙门式和特殊用途的
机器。
.
.
Among
accessories for milling machines, one of the most
widely used is the universal
dividing
head. This is a fixture that rotates the workpiece
to specified angles between individual
machining steps. Typical uses are in milling
parts with polygonal surfaces and in machining
gear
teeth.
铣床使用最广泛的配件是通用的分度头。这是一个夹具在各个加工步骤使工件旋
转到指定角度。典型的用途是加工铣削有多边形表面的零件和加工齿轮齿。
Planers and Shapers These machine tools are
generally used for machining large flat
surfaces although other shapes, such as
grooves, can also be machined. In a planer, the
workpiece travels under the cross-rail
equipped with cutting tools, whereas in a shaper
the
tool travels and the workpiece is
stationary
龙门刨床和牛头刨床这些机床一般用于加工大平面
虽然其他形状如凹槽也
可以加工。在龙门刨床工件上在装有刀具的下轨移动而在牛头刨床工具移动和工件是
固定的。
Because of the size of the
workpieces involved, planers are among the largest
machine tools.
Shapers may be horizontal
or vertical and are also used for machining
notches and keyways
由于所涉及的工件的大小龙门刨床是位于最大的机床之列。刨边机可水平或垂直
也用于加工凹槽和键槽。
Broaching Machines
These machines push or pull broaches, either
horizontally or vertically,
to generate
various external or internal surfaces. They are of
relatively simple construction and
are
actuated hydraulically and have only linear
motion of the broach. Because of the great variety
of
shapes and parts involved, broaching
machines are manufactured in a wide range of
designs and
sizes.
.
.
拉床 这些机器推或拉拉刀水平或垂直从而加工各种内部或外部的表面。他们的构
造相对简单液压驱动可实现拉刀只有直线运动。由于涉及的形状和部分种类繁多拉床
被制造成各式的设计和尺寸。
Drilling Machines These machines are used for
drilling holes, tapping, counterboring,
reaming, and other general-purpose boring
operations. They are usually vertical, the most
common one being a drill press. Drilling
machines are manufactured in a wide variety of
sizes,
from simple bench type units to
radial drills and large production machines with
multiple
spindles.
钻孔机这些机器用于钻孔攻丝锪孔铰孔和其他通用的镗操作。它们通常
是垂直的最常见的一种是钻床。钻床制造成种类繁多的尺寸从简单的板凳类型单元到摇
臂钻床和有多个主轴的大型生产设备。
46课
Computer-aided design
product
CADinvolves the use of computers to create
design drawings and
models. Computer-aided
design is usually associated with interactive
computer graphics
known as a
CAD
system.
计算机辅助设计(CAD)涉及到电脑的使用来创建设计图纸和产品模型。计算
机辅助设计通常
是与交互式计算机图形学(称为CAD系统)。 Computer-aided
design systems are powerful tools
and are used
in the mechanical design and geometric
modeling of products and components
计算机辅助设计系统是强大的工具,用于产品的机械设
计和几何建模和组件 In CADthe
drawing board is replaced by electronic input and
output
devices. When using a CAD systemthe
designer can conceptualize the object to be
designed
.
.
more easily on the
Graphics screen and can
consider
alternative designs or modify a particular design
quickly to meet the necessary design
requirements or changes.
在CAD图纸被电子输入和输出设备。当使用CAD系统中,设计人员
可以概念化设计的对象
更容易在图形屏幕上,可以考虑替代设计或修改一个特定设计迅速满足必要的设计要求或更
改。 The designer can then subject the design to
a variety of engineering analyses and can
identify potential
problems such as
an excessive load or deflection. The speed and
accuracy of such analyses
far
surpass what is available from traditional
methods.
设计师可以设计各种各样的工程分析和可
以识别潜在的问题(如过度负荷或偏转)。这种分析
的速度和准确度远远超过可以从传统的方法是什么。 Draft productivity
rises dramatically.
When something is drawn
onceit never has to be drawn again.
草案生产率大幅上升。当有
了一次,它从来没有再画。 it can be retrieved
from a library ,and can be duplicated, stretched,
sized, and changed in many ways
without having to be redrawn。Cut and paste
techniques are used as labor-saving aids.
它可以从
库检索,可以复制,拉伸,大小,改变在许多方面不用粘贴技术用作省力
艾滋病。 CAD makes possible multiview 2D drawings
and the drawings can be reproduced in
different levels of
reduction and
enlargement. CAD使可能的多视图2
d图纸,图纸可以复制在不同程度的减少和
扩大。 It gives the mechanical
engineer the ability to magnify even the smallest
of components
to ascertain if assembled
components fit properly.
它让机械工程师的能力放大甚至最小的组
件来确定如果组装组件配合得当。 Parts with
different characteristicssuch as movable or
stationary can be assigned different colors on
the display. 部分具有不同特点,如移动或静止
不动的,可以指定不同的颜色显示。
Designers have even more freedom with the advent
of 3-D
parts and manipulate them in endless
variations to achieve the desired results.
设计师有更多自
由随着3 d部分和操纵他们无穷无尽的变化来获得期望的结果。 Through
finite element
analysis stresses can be
applied to be a computer model and the results
graphically displayedgiving the designer
quick feedback on any inherent problems in a
design
before
the creation of a
physical prototype.
通过有限元分析,压力可以被应用到一个计算机模型,结
果以图形方式显示出来,给设计师提
.
.
供快速反馈任何固有的问题在设计物理原型的创建。 In addition to the
design’s geometric
and dimensional
featuresother information such as a list of
materialsspecification and manufacturing
instructionsis stored in the CAD database.
Using such
information ,the designer
can then analyze the economics of alternative
designs.
除了设计的几
何和空间特性,其他信息(如材料的清单,规范,和生产指令)存储在CAD数据库。
使用这些信息,设计师可以分析替代的经济设计。 Computer-aided
manufacturing(CAM)
involves the uses of
computers and computer technology to assist
in all the phases of manufacturing a
product
machining
including process
and production planning
schedulingmanagement
and quality control. Computer-aided design and
computer-aided
manufacturing are often
combined into CADCAM systems.
计算机辅助制造(CAM)涉及计算机
和计算机技术的使用,协助生产一个产品的所有阶段,包括
过程和生产计划、加工、调度、管理和质量控制。计算机辅助设计和计算机辅助制造通常结
合到CAD CAM系统。 This combination allow the
transfer of information from the design stage
into the stage of of planning for
the manufacture of a productwithout the need
to reenter the data on part geometry manually.
这种组合允许转让信息从设计阶段的阶段,规划产品的生产,而不需要手动重新输入数据部
分几何。 The database developed during CAD is
stored then it is processed furtherby CAM
into
the necessary
data and instructions for
operating and controlling production
machinery
equipment
material-handling
and automated testing and inspection for
product quality.
在CAD开发的数据库存储;然后进一
步处理,通过凸轮,到所需的数据和指令操作和控制生产
机械、设备来源,自动化测试和检验产品质量。 In machining
operationsan important feature
of CADCAM is
its capability to describe the tool path for
various operationssuch as NC turningmillingand
drilling. 在加工操作中,CAD
CAM的
一个重要特性是其能力来描述刀具轨迹的各种操作,如数控车
.
.
削、铣削和钻孔。 The instructions
programsare computer generatedand they can be
modified by the programmer to
optimize the tool path .
计算机生成的指令(程序),他们可以由程序员修改优化刀具轨迹。 The
engineer or
technician can then display and visually check the
tool path for possible tool
collisions with
fixtures or other interferences. The tool path can
be modified at any time
accommodate other part
to
shapes to be machined.
工程师或技术员可以显示和视觉检查刀具轨迹的可能的工具与设备
碰撞或其他干扰。工具路
径随时可以修改,以适应其他部分形状加工。 Some typical applications
of CADCAM area
programming for NCCNCand
industrial robots
bdesign of tools and
fixtures and EDM electodescquality control and
inspection
for instancecoordinate-measuring
machines programmed on a CADCAM
workstation
dprocess planning and
scheduling andeplant layout. 一些典型的CAD
CAM的应用是:(a)为数控编程,数控,
和工业机器人;(b)设计的工具和夹具
和EDM electodes;(c)质量控制和检查,例如,坐标测量机CAD
CAM工作站程序;(d)工艺规
划和调度;(e)工厂的布局。 The
emergence of CADCAM has had a major impact on
manufacturingby standardizing product
development and by reducing design
efforttryoutand prototype workit has made
possible significantly
reduced costs
and improved productivity. CAD
CAM的出现已经对生产产生重大影响,通过标
准化产品开发和减少设计工作,调试,和
原型工作;它可能显著降低成本和提高生产力。 The two-engine Boeing
777 passenger airplane
for example, was
designed completed by computer
paperless
design
an
. The plane is constructed
directly from the CADCAM software developed
enhanced CATIA systemand no prototypes or
mockups were built such as were required for
previous
models.
双引擎的波音777客机,例如,设计完成的计算机(无纸化设计)。飞机构造直接从开发
的CAD
.
.
CAM软件(一个增强的CATIA系统)和任何原型和模型建立,如需要以前的模型。
50课 Today, computer numerical control machine
tools are widely used in manufacturing
enterprises.
Computer numerical
control is the automated control of machine tools
by a computer and
computer
program.
今天,计算机数控机床广泛应用于制造企业。计算机数控机床的自动控制是计算机
和计算机
程序。 The CNC machines still perform essentially
the same functions as manually operated
machine toolsbut
movements of the
machine tool are controlled electronically rather
than by hand. CNC machine
tools can
produce the same parts over and over again
with very little variation. They can run day and
night
week
after weekwithout getting
tired. These are obvious advantages over manually
operated
machine tools
which need a
great deal of human interaction in order to do
anything.
数控机器仍执行相同的
函数作为手动机床,但机床控制电子的运动,而不是用手。数控机床可
以产生相同的部分,一次又一次变化很少。他们可以日夜不停地运转,一周又一周,没有累了。
这些明显的优势在手动机床,需要大量的人工交互为了做任何事。 A CNC
machine tool differs
from a manually operated
machine tool only in respect to the specialized
components that make up the CNC system.
The CNC system can be further divided into three
subsystemscontroldriveand feedback. All
of these subsystems must work together to
form
a complete
CNC system.
数控机床不同于一个手动机床只有在尊重专业的组件构成的数控系统。数控系
统可以进一步
分为三个子系统:控制、驱动,和反馈。所有这些子系统必须共同努力,形成一个完整的数控系
统。 1. control system 1。控制系统 The
centerpiece of the CNC system is the control.
Technically
the control is called the machine
control
.
.
unitMCUbut
the most common names used in recent years are
controllercontrol unit
or just plain
control. This is the computer that stores and
reads the program and tells the other components
what to
do.
数控系统控制的核心。技术控制称为机控制单元(MCU),但近年来最常用的名字是控制器,
控
制单元,或者就是简单的控制。这是计算机存储和读取程序,告诉其他组件该做什么。 2.
Drive
system. 2。驱动系统。 The drive system is
comprised of screws and motors that will finally
turn
the part program into motion.
The first component of typical drive system is
a high-precision lead screw called a ball
screw
Fig.50.1.
Eliminating backlash
in a ball screw is very important for two reasons.
Firsthigh-precision
positioning
can
not be achieved if the table is free to move
slightly when it is supposed to be stationary.
Second
materials can be climb-cut
safely if the backlash has been eliminated. Climb
cutting is usually the
most
desirable method for machining on a CNC
machine.
螺丝和汽车的传动系统是由部分程序,最
终将变成运动。第一个组件的典型的驱动系统是一
种高精度丝杠称为滚珠丝杆(Fig.50.1)。消除反应在滚珠螺杆是非常重要的两个原因。首先,
不能实现高精度定位如果表是免费的移动略当它应该是固定的。第二,材料可以安全地同向
如果反弹已经消除。爬上切割通常是最可取的方法在数控加工机器。 Drive
motors are the
second specialized component in
the drive system. The turning of the motor will
turn
the ball screw to directly cause
the machining table to move. Several types of
electric motors are
used on
CNC
control systemsand hydraulic motors are also
occasionally used.
驱动电机驱动系统中的
第二专业组件。电动机的转动将滚珠螺杆直接导致加工表。几种类型
的电机是用在数控控制系统和液压马达也偶尔使用。 The simplest type of
electric motor used
in CNC positioning systems
is the stepper motorsometimes
.
.
called a stepping motor. A
stepper motors rotates a fixed number of degrees
when it receives
an
electrical pulse
and then stops until another pulse is received.
The stepping characteristic makes
stepper
motors easy to control.
最简单的类型的电动机用于数控定位系统是步进电机(有时称为步进
电机)。步进电机旋转固
定数量的度当它收到一个电脉冲,然后停止,直到接收到一个脉冲。步进特性使步进电机容易
控制。 It is more common to use servomotors in
CNC systems today. Servomotors operated in a
smooth
continuous motion—not like
the discrete movements of the stepper motors. This
smooth motion
leads to
highly
desirable machining characteristicsbut they are
also difficult to control. Specialized
hardware
controls and feedback
systems are needed to control and drive these
motors. Alternating current
AC
servomotors are currently the standard choice
for industrial CNC machine tools.
这是今天使用
伺服电机在数控系统中更为普遍。伺服电机运行在一个光滑、连续的活动,如
离散运动的步进电机。这光滑的运动导致高度理想的加工特点,但他们也难以控制。需要专
门的硬件控制和反馈系统控制和驱动这些汽车。交流电伺服电机目前工业数控机床的标准选
择。 3. Feedback System 3。反馈系统 The function of a
feedback system is to provide the control
with
information about the status of the motion
control systemwhich is described in Figure
50.2. 反馈系统的功能是为控制提供运动控制系
统的状态信息,如图50.2所示。 The
control can compare the desired condition to the
actual
condition and make corrections. The
most obvious information to be fed back to the
control on a
CNC machine
控制可以比较所需的条件的实际条件和改正。最明显的信息反馈给控制数控机
器上 tool is
the position of the table and the velocity of the
motors. Other information may also
be fed back
that is not directly related to motion controlsuch
as the temperature of the motor
and the load
on the
spindle—this information protects
the machine from damage.
工具的位置表和汽车的速度。其
他信息也可以反馈,不是直接关系到运动控制,如电动机的温
.
.
度和负载spindle-this信息保护机器免受损坏。
There are two main types of control
systems
open-loop and closed-loop. An open-loop
system does not
have any device to
determine if the instructions were carried out.
For examplein an open-loop
system
the
control could give instructions to turn the motor
10 revolutions. Howeverno information
can come
back to the control to tell it if it
actually turned。All the control knows is that it
delivered the
instructions.
Open-
loop control is not used for critical systemsbut
it is a good choice for inexpensive motion
control
systems in which accuracy
and reliability are not critical.
主要有两种类型的控制系统:开环和闭
环。一个开环系统没有任何设备来确定指令进行。例
如,在一个开环系统,控制可以给指令将电动机10革命。然而,任何信息可以回到控制告诉它,
如果它实际上控制知道是它的指示交付。开环控制不用于关键系统,但这是一个不
错的选择廉价的运动控制系统的精度和可靠性并不是最关键的。 Closed-loop
feedback uses
external sensors to verify that
certain conditions have been met. Of course
position and velocity feedback is of primary
importance to an accurate CNC system. Feedback is
the only
way to ensure that the
machine is behaving the way the control intended
it to behave.
闭环反馈
使用外部传感器验证某些条件已经满足。当然,位置和速度反馈是最重要的一个精
确的数控系统。反馈是唯一的办法,以确保机器的行为控制计划的行为方式。
.