机械手设计外文翻译2

译文一

机械手

机器人是典型的机电一体化装置，它综合运用了机械与精密机械、微电子与计算机、自动控制与驱动、传感器与信息处理以及人工智能等多学科的最新研究成果，随着经济的发展和各行各业对自动化程度要求的提高，机器人技术得到了迅速发展，出现了各种各样的机器人产品。现代工业机器人是人类真正的奇迹工程。一个像人那么大的机器人可以轻松地抬起超过一百磅并可以在误差

+-0.006英寸误差范围内重复的移动。更重要的是这些机器人可以每天24小时永不停止地工作。在许多应用中（特别是在自动工业中）他们是通过编程控制的，但是他们一旦编程一次，他们可以重复地做同一工作许多年。机器人产品的实用化，既解决了许多单靠人力难以解决的实际问题，又促进了工业自动化的进程。

目前，由于机器人的研制和开发涉及多方面的技术，系统结构复杂，开发和研制的成本普遍较高，在某种程度上限制了该项技术的广泛应用，因此，研制经济型、实用化、高可靠性机器人系统具有广泛的社会现实意义和经济价值。由于我国经济建设和城市化的快速发展，城市污水排放量增长很快，污水处理己经摆在了人们的议事日程上来。随着科学技术的发展和人类知识水平的提高，人们越来越认识到污水处理的重要性和迫切性，科学家和研究人员发现塑料制品在水中是用于污水处理的很有效的污泥菌群的附着体。塑料制品的大量需求，使得塑料制品生产的自动化和高效率要求成为经济发展的必然。本文结合塑料一次挤出成型机和塑料抓取机械手的研制过程中出现的问题，综述近儿年机器人技术研究和发展的状况，在充分发挥机、电、软、硬件各自特点和优势互补的基础上，对物料抓取机械手整体机械结构、传动系统、驱动装置和控制系统进行了分析和设计，提出了一套经济型设计方案。采用直角坐标和关节坐标相结合的框架式机械结构形式，这种方式能够提高系统的稳定性和操作灵活性。传动装置的作用是将驱动元件的动力传递给机器人机械手相应的执行机构，以实现各种必要的运动，传动方式上采用结构紧凑、传动比大的蜗轮蜗杆传动和将旋转运动转换为直线运动的螺旋传动。机械手驱动系统的设计往往受到作业环境条件的限制，同时也要考虑价格因素的影响以及能够达到的技术水平。由于步进电机能够直接接收数字量，响应速度快而且工作可靠并无累积误差，常用作数字控制系统驱动机构的动力元件，因此，在驱动装置中采用由步进电机构成的开环控制方式，这种方式既能满足控制精度的要求，又能达到经济性、实用化目的，在此基础上，对步进电机的功率计一算及选型问题经行了分析。在完成机械结构和驱动系统设计的基础上，对物料抓取机械手运动学和动力学进行了分析。运动学分析是路径规

划和轨迹控制的基础，对操作臂进行了运动学正、逆问题的分析可以完成操作空间位置和速度向驱动空间的映射，采用齐次坐标变换法得到了操作臂末端位置和姿态随关节夹角之间的变换关系，采用几何法分析了操作臂的逆向运动学方程求解问题，对控制系统设计提供了理论依据。机器人动力学是研究物体的运动和作用力之间的关系的科学，研究的目的是为了满足是实时性控制的需要，本文采用牛顿-欧拉方法对物料抓取机械手动力学进行了分析，计算出了关节力和关节力矩，为步进电机的选型和动力学分析与结构优化提供理论依据。控制部分是整个物料抓取机械手系统设计关键和核心，它在结构和功能上的划分和实现直接关系到机器人系统的可靠性、实用性，也影响和制约机械手系统的研制成本和开发周期。在控制主机的选用上，采用结构紧凑、扩展功能强和可靠性高的PC工业控制计算机作为主机，配以PCL-839卡主要承担系统功能初始化、数据运算与处理、步进电机驱动以及故障诊断等功能;同时对PCL-839卡的结构特点、功能原理和其高定位功能等给与了分析。硬件是整个控制系统以及极限位置功能赖以存在的物质基础，软件则是计算机控制系统的神经中枢，软件设计的目的是以最优的方式将各部分功能有机的结合起来，使系统具有较高的运行效率和较强的可靠性。在物料抓取机械手软件的设计上，采用的是模块化结构，分为系统初始化模块、数据处理模块和故障状态检测与处理等几部分。主控计算机和各控制单元之间全部由PCL-839卡联系，并且由该卡实现抗干扰等问题，减少外部信号对系统的影响。步进电机的启停频率远远小于其最高运行频率，为了提高工作效率，需要步进电机高速运行并快速启停时，必须考虑它的升，降速控制问题。电机的升降速控制可以归结为以某种合理的力一式控制发送到步进电机驱动器的脉冲频率，这可由硬件实现，也可由软件方法来实现。本文提出了一种算法简单、易于实现、理论意义明确的步进电机变速控制策略:定时器常量修改变速控制方案。该方法能使步进电机加速度与其力矩——频率曲线较好地拟合，从而提高变速效率。而且它的计算量比线性加速度变速和基于指数规律加速度的变速控制小得多。通过实验证明了该方法的有效性。最后，对论文主要研究内容和取得的技术成果进行了总结，提出了存在的问题和不足，同时对机器人技术的发展和应用进行了展望。

研究机械手控制的目的是保持以计算机为基础的机械手的动态响应，以便与一些预先设定的系统性能和理想目标保持一致。一般情况下，机械手的动态性能直接依赖于控制算法的效率和机械手的动态模型。控制问题包括获得自然的机械手系统的动态模型，然后指定相应的控制规则或步骤以达到想要的系统响应和性能。

目前的工业机械臂控制将每一个机械臂的联合看做一个简单的联合伺服。伺服方法不能充分地模仿不同的动力学机械手，因为它忽略了机械手整体的运动和配置。这些控制系统的参数的变化有时是足够重要，以至于使常规的反馈控制方法失效。其结果是减少了伺服响应的速度和阻尼，限制了精度和最终效应的速度，使系统仅适用于有限精度的工作。机械手以这种方式控制速度降低而没有不必要的震动。任何在这一领域和其它领域的机械臂性能增益要求更有效率的动态模型、精密的控制方法、专门的计算机架构和并行处理技术。

在工业生产和其他领域内，由于工作的需要，人们经常受到高温、腐蚀及有毒气体等因素的危害，增加了工人的劳动强度，甚至于危及生命。自从机械手问世以来，相应的各种难题迎刃而解。机械手可在空间抓、放、搬运物体，动作灵活多样，适用于可变换生产品种的中、小批量自动化生产，广泛应用于柔性自动线。机械手一般由耐高温，抗腐蚀的材料制成，以适应现场恶劣的环境，大大降低了工人的劳动强度，提高了工作效率。机械手是工业机器人的重要组成部分，在很多情况下它就可以称为工业机器人。工业机器人是集机械、电子、控制、计算机、传感器、人工智能等多学科先进技术于一体的现代制造业重要的自动化装备。广泛采用工业机器人，不仅可以提高产品的质量与产量，而且对保障人身安全，改善劳动环境，减轻劳动强度，提高劳动生产率，节约原材料消耗以及降低生产成本，有着十分重要的意义。

机械部件有滚珠丝杠、滑轨、气控机械抓手等。电气方面有可编程控制器（PLC）、编程器、步进电机、步进电机驱动器、直流电机、光电传感器、开关电源、电磁阀、旋转码盘、操作台等部件。可编程控制器发出两路脉冲到步进电机驱动器，分别驱动横轴、竖轴的步进电机运转；直流电机拖动底座和手爪的旋转；接近开关、微动开关、旋转码盘将位置信号反馈给主机，由主机发出指令来实现对手臂的伸缩、上下、转动位置的控制；主机发信号到气动电磁阀，以控制手爪的张合来抓放物体。本设计可根据工件的变化及运动流程的要求随时更改相关参数，具有很大的灵活性和可操作性。

外文原文一

manipulator

Robot is a type of mechantronics equipment which synthesizes the last research achievement of engine and precision engine, micro-electronics and computer, automation control and drive, sensor and message dispose and artificial intelligence and so on. With the development of economic and the demand for automation control,

robot technology is developed quickly and all types of the robots products are come into being. The practicality use of robot products not only solves the problems which are difficult to operate for human being, but also advances the industrial automation program. Modern industrial robots are true marvels of engineering. A robot the size of a person can easily carry a load over one hundred pounds and move it very quickly with a repeatability of +/-0.006 inches. Furthermore these robots can do that 24 hours a day for years on end with no failures whatsoever. Though they are reprogrammable, in many applications (particularly those in the auto industry) they are programmed once and then repeat that exact same task for years.

At present, the research and development of robot involves several kinds of technology and the robot system configuration is so complex that the cost at large is high which to a certain extent limit the robot abroad use. To development economic practicality and high reliability robot system will be value to robot social application and economy development. With the rapid progress with the control economy and expanding of the modern cities, the let of sewage is increasing quickly: With the development of modern technology and the enhancement of consciousness about environment reserve, more and more people realized the importance and urgent of sewage disposal. Active bacteria method is an effective technique for sewage disposal，The lacunaris plastic is an effective basement for active bacteria adhesion for sewage disposal. The abundance requirement for lacunaris plastic makes it is a consequent for the plastic producing with automation and high productivity. Therefore, it is very necessary to design a manipulator that can automatically fulfill the plastic holding. With the analysis of the problems in the design of the plastic holding manipulator and synthesizing the robot research and development condition in recent years, a economic scheme is concluded on the basis of the analysis of mechanical configuration, transform system, drive device and control system and guided by the idea of the characteristic and complex of mechanical configuration, electronic, software and hardware. In this article, the mechanical configuration combines the character of direction coordinate and the arthrosis coordinate which can improve the stability and operation flexibility of the system. The main function of the transmission mechanism is to transmit power to implement department and complete the necessary movement. In this transmission structure, the screw transmission mechanism transmits the rotary motion into linear motion. Worm gear can give vary transmission ratio. Both of the transmission mechanisms have a characteristic of compact structure. The design of drive system often is limited by the environment

condition and the factor of cost and technical lever. ''''The step motor can receive digital signal directly and has the ability to response outer environment immediately and has no accumulation error, which often is used in driving system. In this driving system, open-loop control system is composed of stepping motor, which can satisfy the demand not only for control precision but also for the target of economic and practicality. On this basis，the analysis of stepping motor in power calculating and style selecting is also given. The analysis of kinematics and dynamics for object holding manipulator is given in completing the design of mechanical structure and drive system. Kinematics analysis is the basis of path programming and track control. The positive and reverse analysis of manipulator gives the relationship between manipulator space and drive space in position and speed. The relationship between manipulator’s tip position and arthrosis angles is concluded by coordinate transform method. The geometry method is used in solving inverse kinematics problem and the result will provide theory evidence for control system. The f0unction of dynamics is to get the relationship between the movement and force and the target is to satisfy the demand of real time control. in this chamfer, Newton-Euripides method is used in analysis dynamic problem of the cleaning robot and the arthrosis force and torque are given which provide the foundation for step motor selecting and structure dynamic optimal ting. Control system is the key and core part of the object holding manipulator system design which will direct effect the reliability and practicality of the robot system in the division of configuration and control function and also will effect or limit the development cost and cycle. With the demand of the PCL-839 card, the PC computer which has a. tight structure and is easy to be extended is used as the principal computer cell and takes the function of system initialization, data operation and dispose, step motor drive and error diagnose and so on. A t the same time, the configuration structure features, task principles and the position function with high precision of the control card PCL-839 are analyzed. Hardware is the matter foundation of the control. System and the software is the spirit of the control system. The target of the software is to combine all the parts in optimizing style and to improve the efficiency and reliability of the control system. The software design of the object holding manipulator control system is divided into several blocks such as system initialization block, data process block and error station detect and dispose model and so on. PCL-839 card can solve the communication between the main computer and the control cells and take the measure of reducing the influence of the outer signal to the control system. The start and stop frequency of the step motor is far

lower than the maximum running frequency. In order to improve the efficiency of the step motor, the increase and decrease of the speed is must considered when the step motor running in high speed and start or stop with great acceleration. The increase and decrease of the motor’s speed can be controlled by the pulse freque ncy sent to the step motor drive with a rational method. This can be implemented either by hardware or by software. A step motor shift control method is proposed, which is simple to calculate, easy to realize and the theory means is straightforward. The motor'''' s acceleration can fit the torque-frequency curve properly with this method. And the amount of calculation load is less than the linear acceleration shift control method and the method which is based on the exponential rule to change speed. The method is tested by experiment. A t last, the research content and the achievement are sum up and the problems and shortages in main the content are also listed. The development and application of robot in the future is expected.

The purpose of manipulator control is to maintain the dynamic response of a computer-based manipulator in accordance with some prespecified system performance and desired goals. In general, the dynamic performance of a manipulator directly depends on the efficiency of the control algorithms and the dynamic model of the manipulator. The control problem consists of obtaining dynamic models of the physical robot arm system and then specifying corresponding control laws or strategies to achieve the desired system response and performance.

Current industrial approaches to robot arm control treat each joint of the robot arm as a simple joint servomechanism. The servomechanism approach models the varying dynamics of a manipulator inadequately because it neglects the motion and configuration of the whole arm mechanism. These changes in the parameters of the controlled system sometimes are significant enough to render conventional feedback control strategies ineffective. The result is reduced servo response speed and damping, limiting the precision and speed of the end-effector and making it appropriate only for limited-precision tasks. Manipulators controlled in this manner move at slow speeds with unnecessary vibrations. Any significant performance gain in this and other areas of robot arm control require the consideration of more efficient dynamic models, sophisticated control approaches, and the use of dedicated computer architectures and parallel processing techniques.

In the industrial production and other fields, people often endangered by such factors as high temperature, corrode, poisonous gas and so forth at work, which have

increased labor intensity and even jeopardized the life sometimes. The corresponding problems are solved since the robot arm comes out. The robot arms can catch, put and carry objects, and its movements are flexible and diversified. It applies to medium and small-scale automated production in which production varieties can be switched. And it is widely used on soft automatic line. The robot arms are generally made by withstand high temperatures, resist corrosion of materials to adapt to the harsh environment. So they reduced the labor intensity of the workers significantly and raised work efficiency. The robot arm is an important component of industrial robots, and it can be called industrial robots on many occasions. Industrial robot is set machinery, electronics, control, computers, sensors, artificial intelligence and other advanced technologies in the integration of multidisciplinary important modern manufacturing equipment. Widely using industrial robots, not only can improve product quality and production, but also is of great significance for physical security protection, improvement of the environment for labor, reducing labor intensity, improvement of labor productivity, raw material consumption savings and lowering production costs.

There are such mechanical components as ball footbridge, slides, an air control mechanical hand and so on in the design. A programmable controller, a programming device, stepping motors, stepping motors drives, direct current motors, sensor, switch power supply, an electromagnetism valve and control desk are used in electrical connection. The programmable controller output two lines pulses to stepping motors drives to drive the two stepping motors drives on beam and vertical axis; direct current motors drive the rotation of the base and the hand; sensors send signals of location to the mainframe, and the mainframe sends directive to control the extension and contraction, up and down, moves location; the mainframe send signals to control the opening and closing of the hand to carry objects. Related parameters can be changed according to request of the changes of the objects and movement flow at any time change the relevant parameters in the design, so it has great flexibility and operability.

译文二

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。这种机床主要用于直线切削或钻孔、镗孔等场合。

数控系统由下列组件组成：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。

数据输人装置，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。人工方法作为输人数据唯一方法时，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元件。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、一种操作或两者的组合。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，操作者只是简单地上、下工件。穿孔纸带是在带有特制穿孔附件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、纸带穿孔时的物理损害等形成。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，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数控指令，机床按顺序加工工件到图样要求。

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，然后解释数控指令，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，并通过放大来进一步加强信号，然后将信号送到控制单元里的寄存器，由它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个字节的速度阅读，这对保持机床连续动作是必须的，否则，在轮廓加工时，刀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控设备上的安全装置，它可连续补偿控制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查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。接受到的信号与纸带输入的信号相比较，它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刚度。有几个理由可以说明步进电机是一个自动化申请的非常有用的驱动装置。对于一件事物，它被不连续直流电压脉冲驱使,是来自数传计算机和其他的自动化的非常方便的输出控制系统。当多数是索引或其他的自动化申请所必备者的时候，步进电机对运行一个精确的有角进步也是理想的。因为控制系统不需要监听就提供特定的输出指令而且期待系统适当地反应的公开- 环操作造成一个回应环，步进电机是理想的。一些工业的机械手使用高抬腿运步的马乘汽车驾驶员，而且步进电机是有用的在数字受约束的工作母机中。这些申请的大部分是公开- 环,但是雇用回应环检测受到驱策的成份位置是可能的。环的一个分析者把真实的位置与需要的位置作比较，而且不同是考虑过的错误。那然后驾驶员能发行对步进电机的电脉冲，直到错误被减少对准零位。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，将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地用于较重的加工领域。

外文原文二

NUMERICAL CONTROL

Numerical control(N／C)is a form of programmable automation in which the processing equipment is controlled by means of numbers，letters，and other symbols．The numbers，letters，and symbols are coded in an appropriate format to define a program of instructions for a particular workpart 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 major alterations of the processing equipment．

There are two basic types of numerically controlled machine tools：point—to—point and continuous—path(also called contouring)．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 ale analog devices usually connected to a syn-chro-type resolver or potentiometer．In most cases，pushbuttons，switches，and other similar types of selectors aye 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 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 machining 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 all 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 ale prepared on type writers with special tape—punching attachments or in tape punching units connected directly to acomputer 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 produce an acceptable working tape．

While the data on the tape is fed automatically，the actual programming steps ale 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 stores all 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．

Some photoelectric devices are capable of reading at rates 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 the control unit．Signals thus received ale 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 controllers．There are three basic types of NC motions, as follows:

Point-to-point or Positional Control In point-to-point control the machine tool elements (tools, table, etc.) are moved to programmed locations and the machining operations performed after the motions are completed. The path or speed of movement between locations is unimportant; only the coordinates of the end points of the motions are accurately controlled. This type of control is suitable for drill presses and some boring machines, where drilling, tapping, or boring operations must be performed at various locations on the work piece. Straight-Line or Linear Control Straight-Line control systems are able to move the cutting tool parallel to one of the major axes of the machine tool at a controlled rate suitable for machining. It is normally only possible to move in one direction at a time, so angular cuts on the work piece are not possible, consequently, for milling machines, only rectangular configurations can be machined or for lathes only surfaces parallel or perpendicular to the spindle axis can be machined. This type of controlled motion is often referred to

as linear control or a half-axis of control. Machines with this form of control are also capable of point-to-point control.

Continuous Path or Contouring Control In continuous path control the motions of two or more of the machine axes are controlled simultaneously, so that the position and velocity of the can be tool are changed continuously. In this way curves and surfaces can be machined at a controlled feed rate. It is the function of the interpolator in the controller to determine the increments of the individual controlled axes of the machines necessary to produce the desired motion. This type of control is referred to as continuous control or a full axis of control.

Some terminology concerning controlled motions for NC machines has been introduced. For example, some machines are referred to as four-or five-or even

six-axis machines. For a vertical milling machine three axes of control are fairly obvious, these being the usual X, Y, Z coordinate directions. A fourth or fifth axis of control would imply some form of rotary table to index the work piece or possibly to provide angular motion of the work head. Thus, in NC terminology an axis of control is any controlled motion of the machine elements (spindles, tables, etc). A further complication is use of the term half-axis of control; for example, many milling machines are referred to as 2.5-axis machine. This means that continuous control is possible for two motions (axes) and only linear control is possible for the third axis. Applied to vertical milling machines, 2.5axis control means contouring in the X, Y plane and linear motion only in the Z direction. With these machines

three-dimensional objects have to be machined with water lines around the surface at different heights. With an alternative terminology the same machine could be called a 2CL machine (C for continuous, L for linear control). Thus, a milling machine with continuous control in the X, Y, Z directions could be termed be a three-axis machine or a 3c machine, Similarly, lathes are usually two axis or 2C machines. 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，ale 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 load applications．

译文三

带有自动换刀方法的加工中心配置合成

本文件的目的是出席一个自动换刀加工中心配置的综合设计方法，以满足所需的拓扑结构和运动特性。根据坐标系的概念，图论，概括，专业化，和运动合成，这种设计方法，提出和电脑，并与自动换刀多达8个环节的综合加工中心。作为结果，与鼓型刀库，6，7号的加工中心配置和8链接分别是2，13和20。同样，与线性型刀库的加工中心，5，6，7人数的加工中心配置和8联系分别为1，5，20和60。此外，这项工作提供了一个综合的空间开放与拓扑结构和运动的要求类型的机制系统的方法。

导言

加工中心运动学可以被看作是一个开放型的机制，他们与特定的拓扑结构特点的特殊功能。与平面机制的创新设计相关的问题一直是过去几年许多研究课题。然而，开放式的空间结构议案类型的机制设计方法合成不可用。在过去数年，只是在加工中心结构设计的重点几篇文章。杉村等。（1981年）使用的分析方法，调查的机床设计。伊藤和信乃（1982年，1983年和1987年）产生的使用有向图的机床结构配置。列舍托夫和波特曼（1988）提出的合成与功能相同的成型机床配置的配置代码。的配置代码的概念被广泛采用的5配置合成轴机床（石泽等，1991;坂稻崎，1992年）。但是，自动换刀系统没有考虑。该系统自动执行之间的主轴和一个加工中心刀库工具的变化被称为自动换刀（ATC）的。空管在降低机器闲置时间了重要作用，因此，增加加工过程中的生产力。的建议本文是提出一个对加工中心的自动换刀可能的配置系统的一代，是开放式的设计方法，类型空间机制受拓扑和运动约束。

现有的机制

在设计过程的第一步是研究现有的机制和缔结的拓扑结构和运动特性，加工中心机床的4个基本组成部分：一轴，刀库，转变机制的工具组成，以及机床结构包括权力轴的议案。机床结构在很大程度上决定了加工表面，刚度准确性和动态品质。主轴旋转工具机到所需的工件表面。该工具杂志存储工具和行动为他们在加工操作使用适合的岗位。该工具的变化机制执行工具之间的杂志和主轴工具的变化。最简单的ATC是一个没有变化机制的设计工具，工具之间的杂志和

主轴实现相对运动换刀的议案。图3（a）和（b）显示2 3轴鼓型和直线型工具杂志，分别卧式加工中心。代表和分析的拓扑结构和加工中心，运动特色的坐标系统的定义来描述的每一项议案轴加工中心分配为基础的国际标准化组织（ISO，1974）命名。本标准坐标系是右手直角笛卡儿之一，相关的工件安装在一台机器，与校长的线性横向这台机器相一致。对机器的一个组成部分运动产生积极的方向是，这将导致越来越工件的积极方面。追加的卧式加工中心的ISO 标准的原理图如图所示。3。通过分析提供现有的3轴没有工具，改变机制卧式加工中心，我们可以得出结论的拓扑结构和运动特性（燕，陈，1995年）如下。拓扑需求

拓扑要求结束根据现有机制的拓扑结构特点。在我们的例子，链接和3个关节的设计要求轴在其相应的树图的卧式加工中心是：

1、必须有一个为主轴吊坠顶点。

2、必须有一个顶点，那里的路径长度为4主轴，作为工作表。

3、必须有一个根，这是由主轴头路位于工作表中的帧。

4、必须有一个顶点，这是一个从顶点吊灯从帧路径主轴头位于顶点分支的分支为工具杂志。

5、与必须被看作是对分配的主轴转动边事件。

6、之间的主轴头和工作台的边缘，必须指定为棱镜对。

7、工具之间的杂志和分支顶点的边缘，必须指定为转动，棱柱形，或圆柱对。而且，如果有一个转动对或一对圆柱，它必须与工具的事件杂志。

链接分配规则

1、选择一个为主轴吊坠顶点。

2、选择一个顶点，那里的路径长度为主轴是4，如工作表。如果这个顶点不存在，删除此图并转到步骤6。

3、选择一个顶点，它是由主轴头路位于工作台，因为框架。

4、选择一个顶点，这是从挂件顶点从主轴头路径帧分行位于顶点分支，作为工具杂志。如果这个顶点不存在，删除此图并转到步骤6。

5、其他未分配的顶点分配的链接湖

6、完成连接任务。

联合分配规则

1、与主轴边缘事件被指定为一转动一对。

2、在从主轴头路的边缘，工作表中指定为棱镜对。

3、基于路径的长度从分支顶点工具杂志，边缘可分配根据的R，P和C中的专业化联合置换后，我们必须找出这些专门树图受该机制约束的拓扑结构加工中心，我们要建立。对于我们来说，拓扑约束列举如下：

1、该挂件顶点必须是主轴，工具杂志，或工作表。

2、该工具杂志顶点位于从主轴头支到框架。

3、在转动两人必须与主轴或刀库事件，以及圆柱对必须与工具杂志事件。

据联系和联合分配规则，我们可以专门树图的地图集，以获取专业树图。专业化过程可以通过电脑输入到程序树图相邻矩阵和邻接矩阵所需的联系和拓扑结构的数字结果。图7显示了计算机专业流程图和拓扑结构的号码，满足拓扑要求和限制，在表3中列出。

原文三

A Methodology for the Configuration Synthesis of Machining Centers with Automatic Tool Changer The purpose of this paper is to present a design methodology for the configuration synthesis of machining centers with automatic tool changer to meet the required topology and motion characteristics. According to the concept of coordinate system, graph theory, generalization, specialization, and motion synthesis, this design methodology is proposed and computerized, and the machining centers with automatic tool changer up to eight links are synthesized. As the result, for the machining centers with drum type tool magazine, the numbers of configurations of machining centers with 6, 7, and 8 links are 2, 13, and 20, respectively. Similarly, for the machining centers with linear type tool magazine, the numbers of configurations of machining centers with 5, 6, 7, and 8 links are1, 5, 20, and 60, respectively. Furthermore, this work provides a systematic approach for synthesizing spatial

open-type mechanisms with topology and motion requirements.

Introduction

Machining center kinematics may be considered as an open-type mechanism, and they have special functions with specific topology characteristics. The problems associated with the creative design of planar mechanisms have been the subject of a number of studies (Johnson, 1965; Freudenstein and Maki, 1979, 1983; Erdman, et al., 1980; Yan and Hsu, 1983; Yan and Chen, 1985; Yan, 1992) over the pa,st years. However, design methodologies for the structural synthesis of open-type mechanisms with spatial motions are not available. In the past years, just a few articles focused on the configuration design of machining centers. Sugimura et al. (1981) used analytical approach to investigate the machine tool design. Ito and Shinno (1982, 1983, and 1987) generated the structural configuration of machine tools by using directed graphs. Reshetov and Portman (1988) proposed the configuration code for synthesizing the machine tool configurations with the same shaping function. The concept of configuration code was widely used on the configuration synthesis of

5-axis machine tools (Ishizawa, et al, 1991; Sakamoto and Inasaki, 1992). However, automatic tool changerswere not considered. The system that automatically performs tool changes between the spindle and the tool magazine of a machining center is called automatic tool changer (ATC). ATC plays an important role in reducing the machine idle time and therefore increases productivity in machining process.The propose of this paper is to present a design methodology for the systematic generation of all possible configurations of machining centers with automatic tool changer, that are open-type spatial mechanisms subject to topology and motion constraints Existing Mechanisms

The first step of the design process is to study existing mechanisms and conclude their topology and motion characteristics, A machining center is a machine tool consisting of four basic components: a spindle, a tool magazine, a tool change

mechanism, and a machine tool structure including motion of power axes. The machine tool structure largely determines the accuracy of machined surface, stiffness, and dynamic quality. The spindle rotates the tool to machine the workpiece to the desired surface. The tool magazine stores the tools and moves them to suitable positions for use in machining operations. The tool change mechanism executes tool changes between the tool magazine and the spindle. The simplest ATC is a design without a tool change mechanism, and the relative motions between the tool magazine and the spindle achieve tool change motions. Figures 3(a) and (b) show two 3-axis horizontal machining centers with drum type and linear type tool magazines, respectively. To represent and analyze the topological structures and motion characteristics of machining centers, a coordinate system is defined to describe the allocation of each motion axis of the machining centers based on International Organization for Standardization (ISO, 1974) nomenclature. This standard coordinate system is right-handed rectangular Cartesian one, related to a workpiece mounted in a machine and aligned with the principal linear sideways of that machine. The positive direction of movement of a component of a machine is that which causes an increasing positive dimension of the workpiece. The schematic drawings of horizontal machining centers appended to ISO standard are shown in Fig. 3. By analyzing available existing 3-axis horizontal machining centers without tool change mechanism, we conclude their topology and motion characteristics (Yan and Chen, 1995) as follows.

Topology Requirements

Topology requirements are concluded according to the topology characteristics of existing mechanisms. For our example, the design requirements of links and joints of the 3-axis horizontal machining centers in their corresponding tree graphs are:

1. There must be a pendant vertex as the spindle.

2. There must be a vertex, where the length of path to the spindle

is four, as the working table.

3. There must be a root, which is located on the path from the

spindle head to the working table, as the frame.

4. There must be a vertex, which is a pendant vertex branching

from the branch vertex located on the path from the frame to

the spindle head, as the tool magazine.

5. The edge incident with the spindle must be assigned as a

revolute pair.

6. The edges between the spindle head and the working table

must be assigned as prismatic pairs.

7. The edges between the tool magazine and the branch vertexmust be assigned as revolute, prismatic, or cylindrical pairs.And, if there is a revolute pair or a cylindrical pair, it must beincident with the tool magazine.

Based on the topological requirements of existing mechanisms,the assignment rules of links and joints are concluded as follows.

Link assignment rules

1. Select a pendant vertex as the spindle.

2. Select a vertex, where the length of path to the spindle is four, as the working table. If this vertex does not exist, delete this graph and go to step 6.

3. Select a vertex, which is located on the path from the spindle head to the working table, as the frame.

4. Select a vertex, which is the pendant vertex branching from the branch vertex located on the path from the spindle head to the frame, as the tool magazine. If this vertex does not exist, delete this graph and go to step 6.

5. The other unassigned vertices are assigned as links L.

6. Complete the link assignment.

Joint assignment rules

1. The edge incident with the spindle is assigned as a revolute pair.

2. The edges on the path from the spindle head to the working table are assigned as prismatic pairs.

3. Based on the length of path from the branch vertex to tool magazine, the edges can be assigned according to the joint permutations of R, P, and C. After specialization, we must identify these specialized tree graphs subject to topology constraints of the mechanisms of machining centers we would like to create. For our example, the topology constraints are listed as follows:

1. The pendant vertices must be the spindle, the tool magazine, or the working table.

2. The vertex of tool magazine is located on the branch from the spindle head to the frame.

3. The revolute pair must be incident with the spindle or the tool magazine, and the cylindrical pair must be incident with the tool magazine.

According to the link and joint assignment rules, we can specialize the atlas of tree graphs to obtain the specialized tree graphs. The process of specialization can be computerized by inputting adjacent matrices of the tree graphs into the program and resulting with desired link adjacent matrices and the numbers of topological structures. Figure 7 shows the computer flowchart of specialization, and the numbers of topological structures that satisfy the topological requirements and constraints are listed in Table 3.