機器人1960 年初，約瑟夫·恩格柏格和喬治 ·迪沃爾聯(lián)合創(chuàng)建一個機器人公司——美國通用機械公司，從此工業(yè)機器人開始變?yōu)楝F(xiàn)實。機器人并不只是另一種自動化機器。自動化始于工業(yè)革命期間，用機器來完成先前人工完成的工作。然而，這種自動化機器僅僅能做到為它設(shè)計的特定工作，而機器人能執(zhí)行各種各樣的工作。機器人必須有一對手臂。在裝卸自動化機器、噴漆、焊接時，手臂必須能夠復制人類工人的動作，并且能成千上百次完成傳統(tǒng)自動化機器不能完成的工作。機器人的定義機器人工業(yè)協(xié)會(RIA)發(fā)表了一個機器人的定義，試圖闡明哪些機器僅僅是自動化機械，哪些機器才是真正的機器人。RIA 的定義如下：機器人是一種可重新編程的多功能機械手，為實現(xiàn)各種任務(wù)設(shè)計成通過可改變的程序動作來移動材料、零部件、工具、或?qū)ｉT裝置。這個定義比本書末尾 RIA 術(shù)語匯編的定義更加廣泛，是更合適機器人的定義。當我們看到這個短語的定義，我們會了解哪些機械是真正的機器人而哪些機械只是專用自動化機器。首先，機器人是“可重編程的多功能操縱手” 。RIA 的這句話告訴我們，機器人可以通過改變其內(nèi)存中存儲的信息進行示教（重編程）使機器人做不同的工作?？蓪C器人重新編程，使其裝卸自動化機器、噴漆、焊接以及做許多其他的工作（多功能） 。機器人是“機械手” 。機械手是手臂（或手）可以拿起或移動物品，在這一點上，我們知道，機器人是一個可以示教從而做各種不同工作的機械手臂。定義說，機器人“設(shè)計成通過可改變的程序動作來移動材料、零部件、工具、或?qū)ｉT裝置。 ”材料包括木材、鋼材、塑料、紙板在制造產(chǎn)品使用的任何材料。機器人也可以處理已加工完成的零部件。例如，機器人可以將一塊鋼裝入數(shù)控車床，并卸出車床中已加工完成的零件。除了處理材料和零部件，機器人還可以安裝如磨床、緩沖器、螺絲刀、焊槍等工具來執(zhí)行有效的工作。2在制造工廠中機器人也可以配備專門的儀器或設(shè)備來完成特殊的工作。機器人可以安裝攝像機來檢驗零件或產(chǎn)品。也可以配備激光器來精確測量正在加工的零件的尺寸。RIA 的定義用“通過可改變的程序動作來完成各種不同操作”這句話進行結(jié)尾，這句話強調(diào)的事實是：在制造工廠，機器人可以做許多不同的工作。機器人能做的工作種類只受限于應(yīng)用工程師的創(chuàng)造性。機器人的工作由機器人完成的工作可分為兩大類：危險性工作和重復性工作。危險性工作許多機器人應(yīng)用于對人類有危險的工作。這些工作因為有毒氣體、較重材料的處理、高溫材料的處理、在旋轉(zhuǎn)或沖壓機械旁工作或環(huán)境中含有高濃度的輻射而被認為是危險的工作。重復性工作除了擔任危險的工作外，機器人也非常適合做那些在制造工廠里必須做的完全重復的工作。許多工廠的工作要求一個人表現(xiàn)得更像一個機器，而不像一個人類。這項工作可能要將一個工件從這里取起并把它放到那里。同樣的工作每一天都要做上百次。這個工作對判斷力和能力要求較少。這并不是批評做這份工作的人,而是僅僅指出這些工作存在于許多行業(yè)，并且必須完整的完成產(chǎn)品的制作。機器人可以在這樣的工作情況下工作，并且不會抱怨和經(jīng)受與這些工作相關(guān)的疲勞和厭倦。機器人的速度雖然機器人提高了制造工廠的生產(chǎn)率，但是他們也并不是很快。目前，機器人正常運作速度或許已經(jīng)接近人類操作員的速度。機器人的每個主要運動通常需要大約 1 秒時間。對一個機器人來說,讓它們將一塊鋼從輸送機到裝載進數(shù)控車床大約需要十個不同的動作，這個動作將耗費 10 秒。人類操作員能在同樣的時間里完成相同的工作。生產(chǎn)力的增長是一致性的操作的結(jié)果。在工作期間人類操作員一遍一遍的重復同樣的工作，他或她就會慢下來。機器人在程序化的速度下連續(xù)的工作,因此在工作日內(nèi)能完成更多的零件。可以制造定制的自動化設(shè)備做與機器人同樣的工作。這種定制的自動化設(shè)備可以在3不到一半的時間里完成機器人或人們的裝載工作。問題是設(shè)計并制造這種特殊的機器,它只能完成特定的或定制的工作。如果在工作中有任何改變，這臺機器必須完全重建，或儀器必須報廢并設(shè)計制造另一臺新的機器。另一方面，機器人可以重新編程，并且在同一天就可以做新的工作。定制的自動化設(shè)備在工業(yè)中仍然有一定的作用。如果公司知道一份工作多年來不會改變，盡快的定制自動化機器仍然是一個不錯的選擇。在工廠中有其他的一些定制的自動化設(shè)備不能輕易的完成的工作。對于這些工作機器人可能是個不錯的選擇。其中一個例子就是噴漆，它是一項具有危險性的工作，因為從許多油漆散發(fā)出來煙霧都是有毒和易爆的?，F(xiàn)在由機器人來做外殼噴漆的工作。機器人已經(jīng)被“示教”進行噴涂由公司制造的不同大小的外殼尺寸。另外，機器人可以在噴漆室這種有毒的環(huán)境下工作，從而毋須考慮這種煙霧對工作在室內(nèi)的人長期的影響。柔性自動化機器人有另一個優(yōu)點:“他們在制造工廠可以做不同的工作” 。如果機器人在最初購買是用于裝卸沖床并且這個工作在產(chǎn)品設(shè)計上不再需要改變時,在工廠里機器人可以去做另一個工作。例如，它可以移到裝配操作的末端來卸載從輸送機運輸來的已完成的附件，并放到貨盤出貨。準確性和重復性機器人的一個重要特征是能準確的完成其任務(wù)。當機器人編制程序程以執(zhí)行特定的任務(wù)時，它被引導到確定特定的點并且編制程序來記錄所在點的位置，程序編制完成后，機器人轉(zhuǎn)向“運行”并執(zhí)行程序。可惜的是,這個機器人不會走到所有程序設(shè)定點的準確位置，例如，機器人可能會產(chǎn)生與確切點 0.025 英寸的誤差。機器人在第一次執(zhí)行點的計劃中，如果 0.025 英寸是最大誤差，就說明該機器人的精度為 0.025 英寸。除了準確性，我們也關(guān)心機器人的可重復性。一個機器人的重復性是衡量其每次程序執(zhí)行后返回到與其程序點之間的位置接近程度。舉例來說,第一次執(zhí)行程序時，機器人產(chǎn)生 0.025 英寸的誤差，在接下來的執(zhí)行計劃中，機器人在到達這個點之前的循環(huán)會產(chǎn)生 0.010 英寸的誤差。雖然機器人共有 0.035 英寸的誤差。但從最初的編程點，其精度為 0.025 英寸，其重復性為 0.010 英寸。4機器人的主要部件機器人的主要部件有機械手、電源、控制器。機械手用來抓取制造中所需要的資料，零件，或特殊工具。電源提供機械手運動的動力?？刂破饔脕砜刂齐娫?，使機械手完成其任務(wù)。機器人的軸運動機器人機械手的不同運動形式是由機器人的自由度數(shù)或軸來定義的。如果機器人的機械臂可以旋轉(zhuǎn)，這個機器人可以稱為是一個單軸機器人。如果機械手可以上下移動以及旋轉(zhuǎn)，機器人可稱為雙軸機器人。如果除了旋轉(zhuǎn)運動和上下運動，機械手也可以延長其手臂，或稱為“延伸” ，這個機器人可認為是一個三軸機器人(如圖 24.1)。大多數(shù)工業(yè)機器人都有三個主軸運動(旋轉(zhuǎn)、上下、延伸)以及一些短軸運動。圖 24.1 有兩個線性軸和一個旋轉(zhuǎn)軸運動的三軸機器手機器人的短軸存在于機器人的手腕，機器人的手腕與機器人手臂的末端連接。機器人手腕有三個可能的運動或軸：俯仰、翻轉(zhuǎn)、偏轉(zhuǎn)（如圖 24.2） 。手腕上下彎曲是俯仰運動，手腕的轉(zhuǎn)動是翻轉(zhuǎn)運動，手腕的側(cè)面運動偏轉(zhuǎn)運動。5圖 24.2 機器人手腕的三個自由度長軸與短軸的結(jié)合給了機器人六種能完成的動作(六軸或六個自由度數(shù))。許多工業(yè)機器人裝配了所有的六軸，然而，其中有三個長軸，僅僅只有一個或兩個短軸。機器人的分類機器人的手臂末端可以達到的總面積稱為工作區(qū)間。根據(jù)其工作區(qū)間，機器人可以分為四類：圓柱坐標機器人、直角坐標機器人、球坐標機器人和關(guān)節(jié)坐標機器人。也可以按控制方式，將機器人分為三種運動形式：拾取和放置運動、點到點運動、連續(xù)軌跡運動,這些術(shù)語描述機械手在其工作區(qū)間的動作。本文摘選自“機器人及自動化系統(tǒng)” ，羅伯特·L·胡克斯特拉，CmfgE，華南西部出版公司，1986 年。6Robots Industrial robots became a reality in the early 1960's when Joseph Engelberger and George Devol teamed up to form a robotics company they called “Unimation“.A robot is not simply another automated machine. Automation began during the industrial revolution with machines that performed jobs that formerly had been done by human workers. Such a machine, however, can do only the specific job for which it was designed, whereas a robot can perform a variety of jobs.A robot must have an arm. The arm must be able to duplicate the movements of a human worker in loading and unloading other automated machines, spraying paint, welding, and performing hundreds of other jobs that cannot be easily done with conventional automated machines.Definition of A RobotThe Robot Industries Association (RIA) has published a definition for robots in an attempt to clarify which machines are simply automated machines and which machines are truly robots. The RIA definition is as follows:A robot is a reprogrammable multifunctional manipulator designed to move material, parts, tools, or specialized devices through variable programmed motions for the performance of a variety of tasks. This definition, which is more extensive than the one in the RIA glossary at the end of this book, is an excellent definition of a robot. We will look at this definition, one phrase at a time, so as to understand which machines are in fact robots and which machines are little more than specialized automation.First, a robot is a “reprogrammable multifunctional manipulator.” In this phrase RIA tells us that a robot can be taught (reprogrammed) to do more than one fob by changing the information stored in its memory. A robot can be reprogrammed to load and unload machines, weld, and do many other jobs (multifunctional).A robot is a “manipulator”. A manipulator is arm (or hand) that can pick up or move things. At this point we know that a robot is an arm that can be taught to do different jobs.The definition goes on to say that a robot is “designed to move material, parts, tools or Specialized devices“ material, includes wood, steel, plastic, cardboard…anything that is used in the manufacture of a product.7A robot can also handle parts that have been manufactured. For example, a robot can load a piece of steel into an automatic lathe and unload a finished part out of the lathe.In addition to handling material and parts, a robot can be fitted with tools such as grinders, buffers, screwdrivers, and welding torches to perform useful work.Robots can also be fitted with specialized instruments or devices to do special jobs in a manufacturing plant .Robots can be fitted with television cameras for inspection of parts or products. They can be fitted with lasers to accurately measure the size of parts being manufactured.The RIA definition closes with the phrase,“… through variable programmed motions for the performance of a variety of tasks.” This phrase emphasizes the fact that a robot can do many different jobs in a manufacturing plant .The variety of jobs that a robot can do is limited only by the creativity of the application engineer.Jobs for RobotsJobs performed by robots can be divided into two major categories: hazardous jobs and repetitive jobs.Hazardous JobsMany applications of robots are in jobs that are hazardous to humans. Such jobs may be considered hazardous because of toxic fumes, the weight of the material being handled, the temperature of the material being handled, the danger of working near rotating or press machinery, or environments containing high levels of radiation.Repetitive JobsIn addition to taking over hazardous jobs，robots are well suited to doing extremely repetitive jobs that must be done in manufacturing plants .Many jobs in manufacturing plants require a person to act more like a machine than like a human. The job may be to pick a piece up from here and place it there. The same job is done hundreds of times each day. The job requires little or no judgment and little or no skill .This is not said as a criticism of the person who does the job, but is intended simply to point out that many of these jobs exist in industry and must be done to complete the manufacture of products. A robot can be played at such a work station and can perform the job admirably without complaining or experiencing the fatigue and boredom normally associated with such a job.8Robot SpeedAlthough robots increase productivity in a manufacturing plant, they are not exceptionally fast. At present, robots normally operate at or near the speed of a human operator. Every major move of a robot normally takes approximately one second. For a robot to pick us a piece of steel from a conveyor and load it into a lathe may require ten different moves taking as much as ten seconds. A human operator can do the same job in the same amount of time. The increase in productivity is a result of the consistency of operation. As the human operator repeats the same job over and over during the workday, he or she begins to slow down. The robot continues to operate at its programmed speed and therefore completes more parts during the workday.Custom-built automated machines can be built to do the same jobs that robots do. An automated machine can do the same loading operation in less than half the time required by a robot or a human operator. The problem with designing a special machine is that such a machine can perform only the specific job, or which it was built. If any change is made in the job，the machine must he completely rebuilt, or the machine must be scrapped and a new machine designed and built .A robot, on the other hand, could be reprogrammed and could start doing the new job the same day.Custom-built automated machines still have their place in industry. If a company knows that a job will not change for many years, the faster custom-built machine is still a good choice.Other jobs in factories cannot be done easily with custom-built machinery. For these applications a robot may be a good choice .An example of such an application is spray painting. Spray painting is a hazardous job, because the fumes from many paints are both toxic and explosive. A robot is now doing the job of spraying paint on the enclosures. A robot has been “taught“ to spray all the different sizes of enclosures that the company builds. In addition, the robot can operate in the toxic environment of the spray booth without any concern for the long-term effect the fumes might have on a person working in the booth.Flexible AutomationRobots have another advantage: they can be taught to do different jobs in the manufacturing plant. If a robot was originally purchased to load and unload a punch press and the job is no longer needed due to a change in product design，the robot can be moved to another job in the plant. For example, the robot could be moved to the end of the assembly operation and be used to unload the finished enclosures from a conveyor and load them onto a 9pallet for shipment.Accuracy and RepeatabilityOne very important characteristic of any robot is the accuracy with which it can perform its task. When the robot is programmed to perform a specific task, it is led to specific points and programmed to remember the locations of those points .After programming has been completed, the robot is switched to “run“ and the program is executed. Unfortunately, the robot will not go to the exact location of any programmed point，F(xiàn)or example，the robot may miss the exact point by 0.025 in. If 0.025 in. is the greatest error by which the robot misses any point during the first execution of the program，the robot is said to have an accuracy of 0.025 in. In addition to accuracy, we are also concerned with the robot's repeatability. The repeatability of a robot is a measure of how closely it returns to its programmed points every time the program is executed. Say, for example, that the robot misses a programmed point by 0.025 in. the first time the program is executed and that, fluxing the next execution of the program, the robot misses the point it reached during the previous cycle by 0.010 in. Although the robot is a total of 0.035 in. from the original programmed point，its accuracy is 0 .025 in, and its repeatability is 0 .010 in.The Major Parts of a RobotThe major parts of a robot are the manipulator, the power supply, and the controller. The manipulator is used to pick up material, parts, or special tools used in manufacturing. The power supply supplies the power to move the manipulator. The controller controls the power supply so that the manipulator can be taught to perform its task.Axes of Robot MovementThe various movements that the manipulator of a robot can make are defined by its degrees of freedom or axes. If a robot’s manipulator can rotate, the robot is said to be a single-axis robot .If the manipulator can move up and down as well as rotate, the robot is called a two-axis robot. If in addition to the rotational movement and the up-and-down movement，the manipulator can also extend its arm, or “reach“, the robot is said to be a three axis robot(Fig.24.1).Most industrial robots have all three major axes(rotational, up and down, and reach) as well as some minor axes of movement.10Fig.24.1 Three-axis robot with cylindrical (post-type) manipulator, illustrating two linear axes, and one rotational axis, of movementThe minor axes of a robot are found in the robot's wrist, The wrist of a robot is attached to the end of the robot’s arm. These are three possible movements or axes of a rolx3t wrist: pitch, roll and yaw (Fig.24.2).The pitch movement bends the wrist up and down .The roll movement is the twisting of the wrist. The yaw movement is the side-to-side movement of the wrist. 11Fig.24.2 The three possible movements or axes of a robot wristThe combination of the major axes and the minor axes gives the robot six possible movements ( six axes or six degrees of freedom ).Many industrial robots are equipped with all six axes robots, however, have the three major axes but only one or two of the minor axes. Classification of RobotsThe total area that the end of the robot’s: arm can reach is called the work envelope. T Robots can be classified according to their work envelopes into four types: the cylindrical coordinate robot, the rectangular coordinate robot, the spherical coordinate robot, and the jointed arm coordinate robot. They also can be classified by motion control .There are three major classifications of motion for robots: pick-and-place, point-to-point, and continuous path. These terms describe the movements the manipulator can make within its work envelope,Selected from “Robotics and Automated systems”, Robert L. Hoekstra, CmfgE, South-Western Publishing Co, 1986.12教師評語教師簽名：