3NB-1300钻井泥浆泵-泵壳的设计【含CAD图纸、说明书】
本科毕业设计外文文献及译文文献、资料题目:Numerical Control And Robot文献、资料来源:期刊(著作、网络等)文献、资料发表(出版)日期:2000.3.25院 (部):专 业:班 级:姓 名:学 号:指导教师:翻译日期:毕业设计外文文献及翻译- 0 -外文文献: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 毕业设计外文文献及翻译- 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.毕业设计外文文献及翻译- 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 毕业设计外文文献及翻译- 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 robots 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 毕业设计外文文献及翻译- 4 -movement is provided by the manipulators 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 robots 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 毕业设计外文文献及翻译- 5 -wrist flange. The wrist flange allows the robot user to connect different tooling to the wrist for different jobs.The manipulators 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 robots 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 manipulators 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 毕业设计外文文献及翻译- 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 robots 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. 毕业设计外文文献及翻译- 7 -中文译文:数控技术及机器人数控技术数控是可编程自动化技术的一种形式,通过数字,字母和其他一些符号来控制加工设备。数字,字母和符号用适当的格式编码为一个特定工件定义指令程序。当工件改变时,指令程序就改变。这种改变程序的能力使数控适合于中小批量生产,写一段新程序远比对加工设备做大的改动容易得多。数控机床有两种基本形式:点位控制和连续控制(也称为轮廓控制) 。点位控制机床采用异步电动机,因此,主轴的定位只能通过完成一个运动或一个电动机的转动来实现。数控系统有以下组件组成: 数据输入装置,带控制单元的磁带阅读机,反馈装置和切削机床或其他形式的数控设备。数据输入装置,也称“人机联系装置” , 可用人工或全自动方法向机床提供数据。人工方法作为输入数据唯一方法时,只限于少量输入。人工输入装置有键盘,拨号盘,按钮,开关或拨轮选择开关,这些都位于机床附近的一个控制台上。拨号盘通常连到一个同步解析器或电位计的模拟装置上。在大多数情况下,按钮,开关和其他类似的旋钮是数据输入单元。人工输入需要操作者控制每个操作,这是一个既慢又单调的过程,除了简单加工场合或特殊情况,已很少使用。几乎所有情况下,信息都是通过卡片,穿孔纸带或磁带自动提供给控制单元,在传统的数控系统中,八信道穿孔纸带是最常用的数据输入形式,纸带上的编码指令由一系列称为程序块的穿孔组成。每一个程序块代表一种加工功能,一种操作或两种的组合。纸带上的整个数控程序由这些连续数据单元连接而成。带有程序的长带子像电影胶片一样绕在盘子上,相对较短的带子上的程序可通过将纸带两端连接形成一个循环而连续不断地重复使用。带子一旦安装好,就可反复使用而无需进一步处理。此时,操作者只是简单的上下工件。穿孔纸带是在带有特制穿孔附近的打字机或直接连到计算机上的纸带穿孔装置上做成的。纸带制造很少不出错,错误可能由编程,卡片穿孔或编码,纸带穿孔时物理损害等形成。通常,必须要试走几次来排除错误,才能得到一个可用的工作纸带 。虽然纸带上的数据是自动进给的,但实际编程却是手工完成的,在编码纸带做好前,毕业设计外文文献及翻译- 8 -编程者经常要和一个计划人员或工艺工程师一起工作,选择合适的数控机床,决定加工材料,计算切削速度和进给速度,决定所需刀具类型,仔细阅读零件图上尺寸,定下合适的程序开始的零参考点,然后写出程序清单,其上记载有描述加工顺序的编码控制指令,机床按顺序加工工件倒图样要求。控制单元接受和储存编码数据,直至形成一个完整的信息程序块,然后解释程序指令,并引导机床得到所需运动。为更好理解控制单元的作用,可将它与拨号电话进行比较,即每拨一个数字,就储存一个,当整个数字拨好后,电话就被激活,也就完成了呼叫。装在控制单元里的纸带阅读机,通过其内的硅光二极管,检测到穿过移动纸带上的孔漏过的光线,将光束转变成电能,并通过放大来近一步加强信号,然后将信号送到控制单元里的寄存器,由他将动作信号传到机床驱动装置。有些光电装置能以高达每秒 1000 各字节的速度阅读,这对保持机床连续动作是必须的,否则,在轮廓加工时,道具可能在工件上产生划痕。阅读装置必须要能以比控制系统处理数据更快的速度来阅读数据程序块。反馈装置是用在一些数据设备上的安全装置,它可连续补偿空置位置与机床运动滑台的实际位置之间的误差。装有这种直接反馈检测装置的数控机床有一个闭环系统装置。位置控制通过传感器实现,在实际工作时,记录下滑台的位置,并将这些信息送回控制单元。接收到的信号与纸带输入的信号相比较,他们之间的任何偏差都可得到纠正。在另一个称为开环的系统中,机床仅由响应控制器命令的步进电动机驱动定位,工件的精度几乎完全取决于丝杠的精度和机床结构的强度。在这个系统中,没有信息反馈到控制单元的自矫正过程。出现错误动作时,控制单元继续发出电脉冲。比如,一台数控铣床的工作台突然过载,阻力矩超过电机转矩时,并没有响应信号送回到控制器。因为,步进电机对载荷变化不敏感,所以许多数控系统设计允许电机停转。然而,尽管有可能损坏机床结构或机械传动系统,也有使用带有特高转矩步进电机的其他系统,此时,电动机有足够能力来应付系统中任何偶然事故。最初的数控系统采用开环系统。在开,闭环两种系统中,闭环更精确,一般说来更昂贵。起初,因为原先传统的步进电动机的功率限制,开环系统几乎全部用于轻加工场合,最近出现的电液步进电动机已越来越多的用于较重的加工领域。机器人工业机器人是在生产环境中用以提高生产效率的工具,它能做常规乏味的装配线工作,毕业设计外文文献及翻译- 9 -或能做哪些对于工人来说是危险的工作,例如,第一代工业机器人是用来在核电站中更换核燃料棒,如果人去做这项工作,将会遭受到有害放射线的辐射。工业机器人亦能工作在装配线上将小元件装配到一起,如将电子元件安放在电路印制板,扎样, 工人就能从这项乏味的常规工作中解放出来。机器人也能按程序要求用来拆除炸弹,辅助残疾人,在社会的很多应用场合下履行职能。机器人可以认为时将手笔墨段的工具,传感器和手爪移到程序指定位置的一种机器。 当机器到达位置后,它将执行某种任务。这些任务可以使焊接,密封,机器装料,拆卸机装配工件。除了编程以及系统的开停之外,一般来说这些工作可以在无人干预下完成。如下叙述的是机器人系统基本术语:1.机器人是一个可编程,多功能的机械手,通过给要完成的不同任务编制各种动作,它可以移动零件,材料,工具以及特殊装置。这个基本定义引导出后续段落的其他定义,从而描绘出一个完整的机器人系统。2.预编程位置点是机器人为完成工作而必须跟踪的轨迹。在某些位置点上机器人将停下来做某些操作,如装配零件,喷涂油漆或焊接。这些预编程点储存在机器人的储存器中,并为后续的连续操作所调用,而且这些预编程点像其他数据一样,可在日后随工作需要而变化。因而,正是这种可编程的特征,一个工业机器人很像一台计算机,数据可在着了储存,后续调用与编程。3机械手是机器人的手臂,它使机器人能弯屈,延伸和旋转,提供这些运动的是机械手的轴,亦是所谓的机械手的自由度。一个机械手能有 3-16 轴,自由度一词总是与机器人轴数相关。4工具和手爪不是机器人自身组成部分,但它们是安装在机器人手臂末端的附件。这些连在机器人手臂末端的附件可使机器人抬起工件,点焊,刷漆,电弧焊,钻孔,打毛刺以及根据机器人的要求去做各种各样的工作。5机器人系统还可以控制机器人的工作单元,工作单元是机器人执行任务所处的整体环境,该单元包括控制器,机械手,工作平台,安全保护装置或者传输装置。所有这些为保证机器人完成自己任务二必需的装置都包括在这一工作单元中。另外,来自外设的信号与机器人通讯,通知机器人何时装配工件,取工件或放工件到传输装置上。机器人系统有三个基本部件:机械手,控制器和动力源。A . 机械手机械手做机器人系统中粗重工作,它包括两部分:机构和附件,机械手也联接附件基毕业设计外文文献及翻译- 10 -座。机械手基座通常固定在工作区域的地基上,有时基座也可以移动,在这种情况下基座安装在导轨或轨道上,允许机械手从一个位置一道另一个位置。正如前面所提到的那样,附件从机器人基座上延伸出来,附件就是机器人的手臂,它可以使直动型,也可以是轴节型手臂,轴节型手臂也是大家所知的关节型手臂。机械臂使机械手产生各轴的运动。这些轴连在一个安装基座上,然后再联到托架上,托架确保机械手停留在某一位置。在手臂末端上,连接着手腕,手腕有辅助轴和手腕凸缘组成,手腕是让机器人用户在手腕凸缘上安装不同工具来做不同种工作。机械手的轴使机械手在某一区域内执行任务,我们将这个区域为机器人的工作单元,该区域的大小与机械手的尺寸相对应,催着机器人机械结构尺寸的增加,工作单元的范围也必须相应增加。机械手的运动由执行元件或驱动系统来控制,执行元件或驱动系统允许各轴在工作单元内运动。驱动系统可用电器,液压和气压动力,驱动系统所产生的动力经机构转变为机械能,驱动系统与机械传动链相匹配。由链,齿轮和滚珠丝杠组成的机械传动链驱动着机器人的各轴。B.控制器机器人控制器是工作单元的核心,控制器储存着预编程序供后续调
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