本科畢業(yè)設(shè)計外文文獻(xiàn)及譯文文獻(xiàn)、資料題目：Numerical Control And Robot文獻(xiàn)、資料來源：期刊（著作、網(wǎng)絡(luò)等）文獻(xiàn)、資料發(fā)表（出版）日期：2000.3.25院 （部）：專 業(yè)：班 級：姓 名：學(xué) 號：指導(dǎo)教師：翻譯日期：畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 0 -外文文獻(xiàn)：NUMERICAL CONTROL AND ROBOTNumerical controlNumerical control is a form of programmable automation in which the processing equipment is controlled by means of number, letters, and symbols. The numbers, letters, and symbols are coded in an appropriate format to define a program of instructions for a particular work part or job. When the job changes, the program of instructions is changed. The capability to change the program is what makes N/C suitable for low-and medium-volume production. It is much easier to write programs than to make alterations of the processing equipment.There are two basic types of numerically controlled machine tools: point-to-point and continuous-path. Point-to-point machines use unsynchronized motors, with the result that the position of the machining head can be assured only upon completion of a movement, or while only one motor is running. Machines of this type are principally used for straight-line cuts or for drilling or boring. The N/C system consists of the following components: data input, the tape reader with the control unit, feedback devices, and the metal-cutting machine tool or other type of N/C equipment.Data input ,also called “man-to-control link ”，may be provided to the machine tool manually ,or entirely by automatic means. Manual methods when used as the sole source of input data are restricted to a relatively small number of inputs ,Examples of manually operated devices are keyboard dials , pushbuttons ,switches ,or thumbwheel selectors .These are located on a console near the machine . Dials are analog devices usually connected to a synchrony-type resolves or potentiometer. In most cases, pushbuttons, switches, and other similar types of selectors are digital input devices .Manual input requires that the operator set the controls for each operation. It is a slow and tedious process and is seldom justified except in elementary machining applications or in special cases.In practically all cases, information is automatically supplied to the control unit and the machine tool by cards, punched tapes, or by magnetic tape. Eight-channel punched paper tape is 畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 1 -the most commonly used form of data input for conventional N/C systems .The coded instructions on the tape consist of sections of punched holes called blocks .Each block represents a machine function ,a machine operation ,or a combination of the two . The entire N/C program on a tape is made up of an accumulation of these successive data blocks .Programs resulting in long tapes are wound on reels like motion-picture film .Programs on relatively short tapes may be continuously repeated by joining the two ends of the tape to form a loop. Once installed ,the tape is used again and again without further handling .In this case ,the operator simply loads and unloads the parts .Punched tapes are prepared on typewriters with special tape-punching attachments or in tape punching units connected directly to a computer system . Tape production is rarely error-free .Errors may be initially caused by the part programmer ,in card punching or compilation , or as a result of physical damage to the tape during handling ,etc .Several trial runs are often necessary to remove all errors and product an acceptable working tape .While the data on the tape is fed automatically ,the actual programming steps are done manually .Before the coded tape may be prepared ,the programmer ,often working with a planner or a process engineer ,must select the appropriate N/C machine tool ,determine the kind of material to be machined ,calculate the speeds and feeds ,and decide upon the type of tooling needed . The dimensions on the part print are closely examined to determine a suitable zero reference point from which to start the program .A program manuscript is then written which gives coded numerical instructions describing the sequence of operations that the machine tool is required to follow to cut the part to the drawing specifications.The control unit receives and coded data until a complete block of information has been accumulated .It then interprets the coded instruction and directs the machine tool through the required motions.The function of the control unit may be better understood by comparing it to the action of a dial telephone, where, as each digit is dialed, it is stored .When the entire number has been dialed, the equipment becomes activated and the call is completed.Silicon photo diodes ,located in the tape reader head on the control unit ,detect light as it passes through the holes in the moving tape .The light beams are converted to electrical energy , which is amplified to further strengthen the signal . The signals are then sent to registers in the control unit, where actuation signals are relayed to the machine tool drives.畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 2 -Some photoelectric devices are capable of reading at rate up to 1000 characters per second .High reading rates are necessary to maintain continuous machine-tool motion; otherwise, dwell marks may be generated by the cutter on the part during contouring operations .The reading device must be capable of reading data blocks at a rate faster than the control system can process the data.A feedback device is a safeguard used on some N/C installations to constantly compensate for errors between the commanded position and the actual location of the moving slides of the machine tool. An N/C machine equipped with this kind of a direct feedback checking device has what is known as a closed-loop system .Positioning control is accomplished by a sensor which, during the actual operation, records the position of the slides and relays this information back to control unit. Signals thus received are compared to input signals on the tape, and any discrepancy between them is automatically rectified.In an alternative system, called an open-loop system, the machine is positioned solely by stepping motor drives in response to commands by a controller. The degree of work precision depends almost entirely upon the accuracy of the lead screw and the rigidity of the machine structure .With this system ,there is no self-correcting action or feedback of information to the control unit .In the event of an unexpected malfunction , the control unit continues to put out pulses of electrical current .If ,for example ,the table on a N/C milling machine were suddenly to become overloaded , no response would be sent back to the controller .Because stepping motors are not sensitive to load variations , many N/C systems are designed to permit the motors to stall when the resisting torque exceeds the motor torque .Other systems are in use ,however , which , in spite of the possibility of damage to the machine structure or to the mechanical system ,are designed with special high-torque stepping motors .In this case ,the motors have sufficient capacity to “overpower”the system in the event of almost any contingency .The original N/C used the closed-loop system .Of the two systems, closed and open loop, closed loop is more accurate and, as a consequence, is generally more expensive .Initially, open-loop systems were used almost entirely for light-duty applications because of inherent power limitations previously associated with conventional electric stepping motors. Recent advances in the development of electro hydraulic stepping motors have led to increasingly heavier machine 畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 3 -load applications.ROBOTThe industrial robot is a tool that is used in the manufacturing environment to increase productivity .It can be used to do routine and tedious assembly line jobs , or it can perform jobs that might be hazardous to the human worker .For example ,one of the first industrial robots was used to replace the nuclear fuel rods in nuclear power plants .A human doing this job might be exposed to harmful amounts of radiation .The industrial robot can also operate on the assembly line ,putting together small components ,such as placing electronic components on a printed circuit board . Thus, the human worker can be relieved of the routine operation of this tedious task .Robots can also be programmed to defuse bombs, to serve the handicapped, and to perform functions in numerous applications in our society.The robot can be thought of as is a machine that will move an end-of-arm tool, sensor, and/or gripper to a preprogrammed location .When the robot arrives at this location, it will perform some sort of task .This task could be welding, sealing, machine loading, machine unloading, or a host of assembly jobs .Generally, this work can be accomplished without the involvement of a human being, except for programming and for turning the system on and off.The basic terminology of robotic systems is introduced in the following:1 A robot is a reprogrammable, multifunctional manipulator designed to move parts, materials, tools, or special devices through variable programmed motions for the performance of a variety of different task. This basic definition leads to other definitions, presented in the following paragraphs that give a complete picture of a robotic system.2 Preprogrammed locations are paths that the robot must follow to accomplish work. At some of these locations, the robot will stop and perform some operation, such as assembly of parts, spray painting, or welding. These preprogrammed locations are stored in the robot’s memory and are recalled later for continuous operation. Furthermore, these preprogrammed locations, as well as other program data, can be changed later as the work requirements change. Thus, will regard to this programming feature, an industrial robot is very much like a computer, where data can be stored and later recalled and edited.3 The manipulator is the arm of the robot. It allows the robot to bend, reach, and twist. This 畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 4 -movement is provided by the manipulator’s axes, also called the degrees of freedom of the robot. A robot can have from 3 to 16 axes. The term degrees of freedom will always relate to the number of axes found on a robot.4 The tooling and grippers are not part of the robotic system itself ; rather , they are attachments that fit on the end of the robot’ s arm .These attachments connected to the end of the robot’s arm allow the robot to lift parts , spot-weld , paint , arc-weld , drill , debar , and do a variety of tasks , depending on what is required of the robot.5 The robotic system can also control the work cell of the operating robot. The work cell of the robot is the robot is the total environment in which the robot must perform its task. Included within this cell may be the controller, the robot manipulator, a work table, safety features, or a conveyor. All the equipment that is required in order for the robot to do its job is included in the work cell. In addition, signals from outside devices can communicate with the robot in order to tell the robot when it should assemble parts, pick up parts, or unload parts to a conveyor.The robotic system has three basic components: the manipulator, the controller, and the power source.A. Manipulator The manipulator, which does the physical work of the robotic system, consists of two sections: the mechanical section and the attached appendage. The manipulator also has a base to which the appendages are attached. The base of the manipulator is usually fixed to the floor of the work area. Sometimes, though, the base may be movable. In this case, the base is attached to either a rail or a track, allowing the manipulator to be moved from one location to another.As mentioned previously, the appendage extends from the base of the robot. The appendage is the arm of the robot. It can be either a straight, movable arm or a jointed arm. The jointed arm is also known as an articulated arm.The appendages of the robot manipulator give the manipulator its various axes of motion. These axes are attached to a fixed base, which, in turn, is secured to a mounting. This mounting ensures that the manipulator will remain in one location.At the end of the arm, a wrist is connected; the wrist is made up of additional axes and a 畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 5 -wrist flange. The wrist flange allows the robot user to connect different tooling to the wrist for different jobs.The manipulator’s axes allow it to perform work within a certain area. This area is called the work cell of the robot, and its size corresponds to the size of the manipulator. As the robot’s physical size increases, the size of the work cell must also increase.The movement of the manipulator is controlled by actuators, or drive systems. The actuator, or drive system, allows the various axes to move within the work cell. The drive system can use electric, hydraulic, or pneumatic power. The energy developed by the drive system is converted to mechanical power by various mechanical drive systems. The drive systems are coupled through mechanical linkages. These linkages, in turn, drive the different axes of the robot. The mechanical linkages may be composed of chains, gears, and ball screws.B. Controller The controller in the robotic system is the heart of the operation. The controller stores preprogrammed information for later recall, controls peripheral devices, and communicates with computers within the plant for constant updates in production.The controller is used to control the robot manipulator’s movements as well as to control peripheral components within the work cell. The user can program the movement of the manipulator into the controller through the use of a hand-held teach pendant. This information is stored in the memory of the controller for later recall. The controller stores all program data for the robotic system. It can store several different programs, and any of these programs can be edited. The controller is also required to communicate with peripheral equipment within the work cell. For example, the controller has an input line that identifies when a machining operation is completed. When the machine cycle is completed, the input line turns on, telling the controller to position the manipulator so that it can pick up the finished part. Then, a new part is picked up by the manipulator and placed into the machine. Next, the controller signals the machine to start operation. The controller can be made from mechanically operated drums that step through a sequence of events. This type of controller operates with a very simple robotic system. The controllers 畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 6 -found on the majority of robotic systems are more complex devices and represent state-of-the-art electronics. That is, they are microprocessor-operated. These microprocessors are 8-bit, 16-bit, or 32-bit processors. This power allows the controller to be very flexible in its operation. The controller can send electric signals over communication lines that allow it to talk with the various axes of the manipulator. This two-way communication between the robot manipulator and the controller maintains a constant update of the location and the operation of the system. The controller also controls any tooling placed on the end of the robot’s wrist.The controller also has the job of communicating with the different plant computers. The communication link establishes the robot as part of a computer-assisted manufacturing (CAM) system.As the basic definition stated, the robot is a reprogrammable, multifunctional manipulator. Therefore, the controller must contain some type of memory storage. The microprocessor-based systems operate in conjunction with solid-state memory devices. These memory devices may be magnetic bubbles, random-access memory, floppy disks, or magnetic tape. Each memory storage device stores program information for later recall or for editing.C. Power supply The power supply is the unit that supplies power to the controller and the manipulator. Two types of power are delivered to the robotic system. One type of power is the AC power for operation of the controller. The other type of power is used for driving the various axes of the manipulator. For example, if the robot manipulator is controlled by hydraulic or pneumatic drives, control signals are sent to these devices, causing motion of the robot. For each robotic system, power is required to operate the manipulator. This power can be developed from either a hydraulic power source, a pneumatic power source, or an electric power source. These power sources are part of the total components of the robotic work cell. 畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 7 -中文譯文：數(shù)控技術(shù)及機器人數(shù)控技術(shù)數(shù)控是可編程自動化技術(shù)的一種形式，通過數(shù)字，字母和其他一些符號來控制加工設(shè)備。數(shù)字，字母和符號用適當(dāng)?shù)母袷骄幋a為一個特定工件定義指令程序。當(dāng)工件改變時，指令程序就改變。這種改變程序的能力使數(shù)控適合于中小批量生產(chǎn)，寫一段新程序遠(yuǎn)比對加工設(shè)備做大的改動容易得多。數(shù)控機床有兩種基本形式：點位控制和連續(xù)控制（也稱為輪廓控制） 。點位控制機床采用異步電動機，因此，主軸的定位只能通過完成一個運動或一個電動機的轉(zhuǎn)動來實現(xiàn)。數(shù)控系統(tǒng)有以下組件組成: 數(shù)據(jù)輸入裝置，帶控制單元的磁帶閱讀機，反饋裝置和切削機床或其他形式的數(shù)控設(shè)備。數(shù)據(jù)輸入裝置，也稱“人機聯(lián)系裝置” ， 可用人工或全自動方法向機床提供數(shù)據(jù)。人工方法作為輸入數(shù)據(jù)唯一方法時，只限于少量輸入。人工輸入裝置有鍵盤，撥號盤，按鈕，開關(guān)或撥輪選擇開關(guān)，這些都位于機床附近的一個控制臺上。撥號盤通常連到一個同步解析器或電位計的模擬裝置上。在大多數(shù)情況下，按鈕，開關(guān)和其他類似的旋鈕是數(shù)據(jù)輸入單元。人工輸入需要操作者控制每個操作，這是一個既慢又單調(diào)的過程，除了簡單加工場合或特殊情況，已很少使用。幾乎所有情況下，信息都是通過卡片，穿孔紙帶或磁帶自動提供給控制單元，在傳統(tǒng)的數(shù)控系統(tǒng)中，八信道穿孔紙帶是最常用的數(shù)據(jù)輸入形式，紙帶上的編碼指令由一系列稱為程序塊的穿孔組成。每一個程序塊代表一種加工功能，一種操作或兩種的組合。紙帶上的整個數(shù)控程序由這些連續(xù)數(shù)據(jù)單元連接而成。帶有程序的長帶子像電影膠片一樣繞在盤子上，相對較短的帶子上的程序可通過將紙帶兩端連接形成一個循環(huán)而連續(xù)不斷地重復(fù)使用。帶子一旦安裝好，就可反復(fù)使用而無需進(jìn)一步處理。此時，操作者只是簡單的上下工件。穿孔紙帶是在帶有特制穿孔附近的打字機或直接連到計算機上的紙帶穿孔裝置上做成的。紙帶制造很少不出錯，錯誤可能由編程，卡片穿孔或編碼，紙帶穿孔時物理損害等形成。通常，必須要試走幾次來排除錯誤，才能得到一個可用的工作紙帶 。雖然紙帶上的數(shù)據(jù)是自動進(jìn)給的，但實際編程卻是手工完成的，在編碼紙帶做好前，畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 8 -編程者經(jīng)常要和一個計劃人員或工藝工程師一起工作，選擇合適的數(shù)控機床，決定加工材料，計算切削速度和進(jìn)給速度，決定所需刀具類型，仔細(xì)閱讀零件圖上尺寸，定下合適的程序開始的零參考點，然后寫出程序清單，其上記載有描述加工順序的編碼控制指令，機床按順序加工工件倒圖樣要求。控制單元接受和儲存編碼數(shù)據(jù)，直至形成一個完整的信息程序塊，然后解釋程序指令，并引導(dǎo)機床得到所需運動。為更好理解控制單元的作用，可將它與撥號電話進(jìn)行比較，即每撥一個數(shù)字，就儲存一個，當(dāng)整個數(shù)字撥好后，電話就被激活，也就完成了呼叫。裝在控制單元里的紙帶閱讀機，通過其內(nèi)的硅光二極管，檢測到穿過移動紙帶上的孔漏過的光線，將光束轉(zhuǎn)變成電能，并通過放大來近一步加強信號，然后將信號送到控制單元里的寄存器，由他將動作信號傳到機床驅(qū)動裝置。有些光電裝置能以高達(dá)每秒 1000 各字節(jié)的速度閱讀，這對保持機床連續(xù)動作是必須的，否則，在輪廓加工時，道具可能在工件上產(chǎn)生劃痕。閱讀裝置必須要能以比控制系統(tǒng)處理數(shù)據(jù)更快的速度來閱讀數(shù)據(jù)程序塊。反饋裝置是用在一些數(shù)據(jù)設(shè)備上的安全裝置，它可連續(xù)補償空置位置與機床運動滑臺的實際位置之間的誤差。裝有這種直接反饋檢測裝置的數(shù)控機床有一個閉環(huán)系統(tǒng)裝置。位置控制通過傳感器實現(xiàn)，在實際工作時，記錄下滑臺的位置，并將這些信息送回控制單元。接收到的信號與紙帶輸入的信號相比較，他們之間的任何偏差都可得到糾正。在另一個稱為開環(huán)的系統(tǒng)中，機床僅由響應(yīng)控制器命令的步進(jìn)電動機驅(qū)動定位，工件的精度幾乎完全取決于絲杠的精度和機床結(jié)構(gòu)的強度。在這個系統(tǒng)中，沒有信息反饋到控制單元的自矯正過程。出現(xiàn)錯誤動作時，控制單元繼續(xù)發(fā)出電脈沖。比如，一臺數(shù)控銑床的工作臺突然過載，阻力矩超過電機轉(zhuǎn)矩時，并沒有響應(yīng)信號送回到控制器。因為，步進(jìn)電機對載荷變化不敏感，所以許多數(shù)控系統(tǒng)設(shè)計允許電機停轉(zhuǎn)。然而，盡管有可能損壞機床結(jié)構(gòu)或機械傳動系統(tǒng)，也有使用帶有特高轉(zhuǎn)矩步進(jìn)電機的其他系統(tǒng)，此時，電動機有足夠能力來應(yīng)付系統(tǒng)中任何偶然事故。最初的數(shù)控系統(tǒng)采用開環(huán)系統(tǒng)。在開，閉環(huán)兩種系統(tǒng)中，閉環(huán)更精確，一般說來更昂貴。起初，因為原先傳統(tǒng)的步進(jìn)電動機的功率限制，開環(huán)系統(tǒng)幾乎全部用于輕加工場合，最近出現(xiàn)的電液步進(jìn)電動機已越來越多的用于較重的加工領(lǐng)域。機器人工業(yè)機器人是在生產(chǎn)環(huán)境中用以提高生產(chǎn)效率的工具，它能做常規(guī)乏味的裝配線工作，畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 9 -或能做哪些對于工人來說是危險的工作，例如，第一代工業(yè)機器人是用來在核電站中更換核燃料棒，如果人去做這項工作，將會遭受到有害放射線的輻射。工業(yè)機器人亦能工作在裝配線上將小元件裝配到一起，如將電子元件安放在電路印制板，扎樣， 工人就能從這項乏味的常規(guī)工作中解放出來。機器人也能按程序要求用來拆除炸彈，輔助殘疾人，在社會的很多應(yīng)用場合下履行職能。機器人可以認(rèn)為時將手筆墨段的工具，傳感器和手爪移到程序指定位置的一種機器。 當(dāng)機器到達(dá)位置后，它將執(zhí)行某種任務(wù)。這些任務(wù)可以使焊接，密封，機器裝料，拆卸機裝配工件。除了編程以及系統(tǒng)的開停之外，一般來說這些工作可以在無人干預(yù)下完成。如下敘述的是機器人系統(tǒng)基本術(shù)語：1.機器人是一個可編程，多功能的機械手，通過給要完成的不同任務(wù)編制各種動作，它可以移動零件，材料，工具以及特殊裝置。這個基本定義引導(dǎo)出后續(xù)段落的其他定義，從而描繪出一個完整的機器人系統(tǒng)。2.預(yù)編程位置點是機器人為完成工作而必須跟蹤的軌跡。在某些位置點上機器人將停下來做某些操作，如裝配零件，噴涂油漆或焊接。這些預(yù)編程點儲存在機器人的儲存器中，并為后續(xù)的連續(xù)操作所調(diào)用，而且這些預(yù)編程點像其他數(shù)據(jù)一樣，可在日后隨工作需要而變化。因而，正是這種可編程的特征，一個工業(yè)機器人很像一臺計算機，數(shù)據(jù)可在著了儲存，后續(xù)調(diào)用與編程。3．機械手是機器人的手臂，它使機器人能彎屈，延伸和旋轉(zhuǎn)，提供這些運動的是機械手的軸，亦是所謂的機械手的自由度。一個機械手能有 3-16 軸，自由度一詞總是與機器人軸數(shù)相關(guān)。4．工具和手爪不是機器人自身組成部分，但它們是安裝在機器人手臂末端的附件。這些連在機器人手臂末端的附件可使機器人抬起工件，點焊，刷漆，電弧焊，鉆孔，打毛刺以及根據(jù)機器人的要求去做各種各樣的工作。5．機器人系統(tǒng)還可以控制機器人的工作單元，工作單元是機器人執(zhí)行任務(wù)所處的整體環(huán)境，該單元包括控制器，機械手，工作平臺，安全保護(hù)裝置或者傳輸裝置。所有這些為保證機器人完成自己任務(wù)二必需的裝置都包括在這一工作單元中。另外，來自外設(shè)的信號與機器人通訊，通知機器人何時裝配工件，取工件或放工件到傳輸裝置上。機器人系統(tǒng)有三個基本部件：機械手，控制器和動力源。A . 機械手機械手做機器人系統(tǒng)中粗重工作，它包括兩部分：機構(gòu)和附件，機械手也聯(lián)接附件基畢業(yè)設(shè)計外文文獻(xiàn)及翻譯- 10 -座。機械手基座通常固定在工作區(qū)域的地基上，有時基座也可以移動，在這種情況下基座安裝在導(dǎo)軌或軌道上，允許機械手從一個位置一道另一個位置。正如前面所提到的那樣，附件從機器人基座上延伸出來，附件就是機器人的手臂，它可以使直動型，也可以是軸節(jié)型手臂，軸節(jié)型手臂也是大家所知的關(guān)節(jié)型手臂。機械臂使機械手產(chǎn)生各軸的運動。這些軸連在一個安裝基座上，然后再聯(lián)到托架上，托架確保機械手停留在某一位置。在手臂末端上，連接著手腕，手腕有輔助軸和手腕凸緣組成，手腕是讓機器人用戶在手腕凸緣上安裝不同工具來做不同種工作。機械手的軸使機械手在某一區(qū)域內(nèi)執(zhí)行任務(wù)，我們將這個區(qū)域為機器人的工作單元，該區(qū)域的大小與機械手的尺寸相對應(yīng)，催著機器人機械結(jié)構(gòu)尺寸的增加，工作單元的范圍也必須相應(yīng)增加。機械手的運動由執(zhí)行元件或驅(qū)動系統(tǒng)來控制，執(zhí)行元件或驅(qū)動系統(tǒng)允許各軸在工作單元內(nèi)運動。驅(qū)動系統(tǒng)可用電器，液壓和氣壓動力，驅(qū)動系統(tǒng)所產(chǎn)生的動力經(jīng)機構(gòu)轉(zhuǎn)變?yōu)闄C械能，驅(qū)動系統(tǒng)與機械傳動鏈相匹配。由鏈，齒輪和滾珠絲杠組成的機械傳動鏈驅(qū)動著機器人的各軸。B.控制器機器人控制器是工作單元的核心，控制器儲存著預(yù)編程序供后續(xù)調(diào)