左臂壳体钻孔专用机床设计【含CAD图纸+文档】
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压缩包内含有CAD图纸和说明书,均可直接下载获得文件，所见所得，电脑查看更方便。Q 197216396 或 11970985
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组合机床的机器整合和控制设计D. M. Tilbury 和 S. Kota组合机械系统机械工程部和应用技巧工程研究中心密西根大学Ann Arbor, MI 48109-2125ftilbury,kotag摘要：在文中，我们针对组合机床及其相关控制系统给出了一个系统设计程序。 设计的出发点是一系列在给定的部位或者是部件上的操作，这些操作被分 解为一系列机器必须执行的功能，每个功能对应着一个机器控制组件， 一旦一个机器构成了一系列的组件，整个机床就被连接起来了。控制设计 由操作序列控制组件、操作者接口控制组件和转变模态的逻辑来完成。关于组合机床的机器整合和控制设计以下是详细的描述。I.介绍在今天的竞争市场中，制造系统必须要快速适应不同客户的需求并尽可能地减少产品的生命周期。传统的生产流水线只为高价值的产品设计，在一个固定的自动化模式下操作，因此不能很快适应产品设计方面的改变。而在另一方面，传统的以加工中心为基础的弹性制造系统提供了广义的弹性但是通常非常慢和昂贵而且不会因为特殊产品和系列产品优化。密西根大学打算发展理论以便为组合机床系统促成技术34。新的系统能组合生产任意的新的部件，而非为某个部件而建立的专有制造系统。在文中, 我们描述一部整合机器和控制设计系统如何实现组合的。为了要完全地提供工件加工过程中所需要的功能和能力，RMTs 被设计成一个给定的部件。给定一系列要运行的操作，RMTs 就可以藉由装配适当的机器组件来组合起来。每个运动部件在库中都有一个控制部件与它相联系。当机械组件被装配起来后，控制组件将会被连接起来，机器也就准备好运行了。广泛而耗时的专有控制系统将不再需要。在第II部分我们将会描述如何来通过一系列基础机械组件来设计该机床，这项研究部分被NSF-ERC 所支持并授予编号EEC95-92125。用一种定义明确的方式衔接。第III部分描述了该控制是如何同样通过一个控制组件库被装配。在第IV部分我们将对该模组工程在设计和控制方面进行多层次的组合。文章第v部分将以对将来工作的展望来结尾。II.机械设计在制造系统配置的持续的工作在密西根大学论及开始的问题从零件(或部件) 描述和提取机器操作必须制造零件（部件）。操作根据公差被聚集，次序实行，而且需要系统周期，根据每个“群”都能够在机床上独立制造的意图，在这里我们对图1上所示的V6和V8的圆筒头进行一系列的钻孔操作。被输入到组合机床内的设计程序是程序设计者为进行这一操作而生成的位置数据。图2显示了包含定位和钻孔信息在内的样品数据。RMT设计程序包含了三个主要的设计阶段：任务阐明、组件选择和评估。在一段简短的文字回顾后，这三个阶段将会在本部分概略说明。A 相关研究虽然组合在机械制造系统中只是一个相对新的概念，然而出版了的文章中却很少有关于组合机床设计的。但是，模组机床已经上市多年，也有一些关于机械手、模组机械的文章，多少和组合机床的设计有一些关系。例如，Shinno 和 Ito17181920 计划建立一个结构组合机床的理论，他们将机床分解成简单的几何形式，例如盒子、汽缸盖等等。Yan 和Chen211 把这一个工作延长到机械中心的结构设计。Ouyang 等人 12 运用Ito的方法为模组机床的综合而且发展列举机床组件的一个方法。Paradis 和 Khosla15 决定了模组的装配时如何最佳地配置任务。Fig.1.二个样品零件，需要进行的操作是给汽缸盖上钻定位孔，在V8汽缸盖上，在一条线上二个这样的定位孔，在V6汽缸盖上有8个孔。 Fig.2.图1中被显示的样品零件钻孔时的数据，CL文件是一个从CAD系列 （譬如IDEAS）中产生的，它包含主轴转速、进给量和冷冻剂数据Chen2讲述了为指定工作发现最佳化装配结构的方法，他的程序以影响装配的矩阵为基础。而且运用了一个遗传基因的运算法则来以最佳化的方法解决问题。在系统前面，罗杰和 Bottaci16 讨论了组合制造系统的重要性，欧恩等人 13发明了模组制造系统综合为教育的目标规划。在文中,运动表现的传统方法拓扑结构 (也就是螺丝钉理论, 曲线图理论, 等等。) 是用来获取 RMTs 的特性的。 这些数学的功能作为拓扑综合,功能-分解, 而且映射程序; 细节功能在 9 中被发现。B.任务阐明RMT 的设计从任务阐明开始, 哪些需要分析切削刀地点数据确定是必要完成的套作用需要的运动学行动。分为三个步骤。首先, 图表用来抽象地表示一个运动。这些图表然后被分解成功能, 并且功能最后被映射机器存在在库里的模块。机床结构的图表表示法考虑到供选择配置的系统的列举并且提供证明方法非同形图表。图表表示法并且被使用为簿记分配机器模块到图表元素。图表包括一套端点被连接一起由边缘。在使用一张图表作为一个抽象表示法机械工具结构, 我们定义二种不同类型端点: 类型0和类型1。端点代表一个物理对象与二个口岸; 各个口岸代表在哪里它可能附有的对象 。类型0的 端点输入和输出口成一条直线, 反之类型1的端点输入和输出口互相垂直。机器制造的任务就是通过刀具是平行还是垂直工件来说明是类型0还是类型1的。图4 显示一张图表为类型0的任务。四个类型1的端点与几个类型0的端点构成一个C形式的机械结构。由于类型0 端点不会改变定位方向, 他们可能被各种各样的组合当成间隔号。根端点代表机床的基础或层。选择根端点不是唯一的; 不同的选择将收效在分明机床的设计上。结构作用是分配端点到图表; 运动学作用 (需要) 的地方被分配到边缘。例如, 图4 显示一个例子怎样平移行动 X; Y 和Z 方向可能被分配到图表边缘, 代表相对行动在物理对象之间由边缘的二个端点代表。机床的基本的功能就是刀具和工件之间的相对运动。这些运动学作用将由同类矩阵 11 来表示; 机床所需要的功能将被输入在矩阵T 。机器制造行动必要执行一项指定的任务是从操作序列获得。在图2显示的程序文件包含了刀具位置和运动在笛卡儿坐标系下的同一系统。 Fig.3.高等操作序列，表示原因的产生和同作，序列的这一概要表现操作源于图2显示的CL数据，它将会用来设计序列控制。 Fig.4.一个表示机床结构的图，平移运动被分配到图表边缘，端点有结构的功能性。 Fig.5.功能分解模板例如, 第一个运动可以写成：这里P1 代表机床的位置和刀具的安置, 而F1代表进给运动。从在任何二个毗邻位置之间的改变,运动可以描述成： 其它运动描述相似。对应于各类型机器操作, 一个模板被检索如同一个起点在辨认各种各样运动学作用必要执行用机器制造任务。例如, 模板为碾碎和钻井操作表示, 运动学作用是必要的为成主轴革命, 工件进给和工件安置。由使用这块模板, 与确切进给和安置的信息提供在处理计划, 我们能获得是必要的确切的运动学作用譬如工件自转, 依照表5的描述翻译x; Y, 和Z 为进给和翻译Z 为工件安置。每个运动学作用被辨认在作用分解阶段被映射对图表的边缘描述上面。被分配作用到不同的边缘能引起多种解答。由于纯粹地平移行动是可交换的, 他们的次序在图表能被互换。在作用映射, 重要信息是螺丝拓扑结构行动(包括纯净的旋转的行动) 和机床的拓扑结构。Fig.6.图4的结构曲线图能够被多种不同的模块选择。Fig.7.机床模块表示法。CAD 模型一张幻灯片为一种模件机械工件被显示在左边,它的矩阵被显示在右边。C. 组件选择商业可利用的模块从被挑选模块库为每个作用(结构如同运动学) 被映射对图表在任务阐明阶段。数据被存放为各个模块库包括同源矩阵代表它的运动学或结构作用, 转弯传染媒介由运动信息补充,一的范围服从矩阵代表模块突端, 模块连通性信息, 和功率需要量(为活跃模块譬如主轴和幻灯片) 。第一步在模块选择将比较同类模块的变革矩阵与任务要求矩阵这样当适当模块被选择符合任务要求, 所有模块矩阵产品应该是相等的与需要任务矩阵: T = T1T2Tn 。再, 那里也许是模块许多可能的选择为一指定的结构配置。图6 显示怎么不同的幻灯片, 主轴, 并且结构元素可能是装配的达成协议对图表图4 。一个幻灯片模块, 以它的CAD 模型和变革矩阵, 被显示在表7 。它是可胜任一线性行动的方向, 由 1个表明它的变革矩阵。它的数据库词条, 被显示在表里 I, 存放不仅它的变革矩阵而且制造商名字, 模型号, 最初的位置, 力量水平, 和行动数据。转弯传染媒介被增添信息关于极小, 最初, 和最大位移模块。D.评估一套运动学可行的模块一次是选择, 有效的机器设计必须被评估。标准为组合机床的评估工具由上述系统的做法综合包括工作信封, 自由度的数量, 模块被使用的数量, 和动态曲度。运动学自由程度的数量机器的工具必须被保留对极小值必需见面要求, 减少驱动力量和使误差链减到最小。各个活跃例子展示设计由这方法学引起确切地有自由程度的数量必要执行必需的机器操作在指定的部份 10 。引起使用这的机械工具设计图1 的例子零件的方法学被显示在表8 。有效的设计必须被评估谈到期望的准确性。整个机器的曲度工具, 最重要的因素的当中一个在表现, 是根据模块估计服从矩阵和连接的方法。 Fig.8.为二个不同零件设计的组合机床。III. 控制设计用模块构成机床,便形成控制。在这一工作中, 我们集中于逻辑控制为机器模块的程序化和协调; 分离系统形式主义被显示在 6 上。用一个控制模块联系了各个活跃机器模块; 我们提到这些作为机器控制模块。在机器设计, 那里是连接的被动元素活跃元素一起。在控制设计, 那里必需并且连接机器的模块控制模块。控制的整体建筑学系统为RMT 被显示在表9 。结构是相似为或者二个机器被显示在上图8; 为V-8 机器, 没有Y轴方向的控制模块。依照显示, 机器控制模块是在最低水平; 这交互式直接地以机械系统。用户接口控制模块是在最高的水平, 互动与用户通过电钮和显示。操作序列控制模块被定义根据了高级操作序列为部份依照图3显示。三个模块处理方式开关逻辑。在这个部分, 我们简要描述每个这些型控制模块并且他们的互作用和协调。A.机器控制模块各个机器控制模块有一个明确定义的接口规格: 它接受分离事件命令从一个指定的集合, 和回归分离事件反应从被给集合。在控制模块之内将是所有连续易变控制, 譬如伺服操纵为轴。这连续控制被设计使用标准PID 算法并且轴参量譬如惯性, 力量, 主角螺丝投, 来自机器模块定义。在加法, 各个机器控制模块将包含控制为任一个机器服务联系了机器模块, 譬如润滑或蓄冷剂。因而, 各个机器控制模块是一位独立性的控制器为它伴随的机器模块, 和可能被设计和独立地测试机器的剩余。机器控制模块的设计必须完成只一次为各个机器模块在图书馆里。每当机器模块被使用在机器设计, 控制模块可能被使用在伴生的控制设计。控制模块也许独立地被使用, 与它自己的处理能力、I/O 和网络连接控制系统的剩余, 或它也许被使用作为片断整体机器控制器被实施集中化时尚。一个机器控制模块的例子为幻灯片是显示在上图10 。有四命令模块可能接受: 行动向位置x, 中止, 凹凸部在正面 x, 和凹凸部在消极x 方向。当它完成了必要的操作, 它返done 的命令。定时器是包括的(但没显示); 如果规定的时间过去了而一个完成命令都没有返回, error 命令将返回。Fig.10. 滑控制器。幻灯片控制器包括(在之内箱子) 伺服控制器为幻灯片。当幻灯片到达了命令的位置时, done 命令返回。B.操作序列 操作序列模块被定义从高阶序列从切削刀地点数据被提取显示在上图3 。这控制主要结构模块是状态序列代表序列操作必须进行在零件; 等待状态是包括的在各步的完成。图 11表示操作序列模块为机器图8(b) 和操作序列图3 。简单错误处理仅仅通过错误用户界面被合并在设计但不是显示在上图为朴素。如果reset 命令被接受, 主轴被关闭并且幻灯片被重新设置对它的位置。操作序列为V6 机器相似, 但有更多操作因为那里是需要程序化的二个线性轴。依照被显示整体结构图9, 那里是二个口岸对操作序列控制模块: 你连接到自动方式控制模块, 和另连接到冲突验查员。接口对操作序列控制模块被显示在表12 。C.模块控制结构用户接口控制模块与用户相处融洽通过一套电钮转动控制系统断断续续, 开关在控制方式之间, 和单向通过操作序列。它的主函数是通过用户命令通过对控制器的剩余, 并且显示机器的现状用户。机床控制器有几个不同的方式。在自动方式, 操作序列连续地执行得; 其它方式也许执行操作序列只一次。在步方式下, 电钮命令必须是过去经常创始操作序列的每步, 和在人工式, 更加美好的控制是可利用的通过凹凸部命令那移动活跃元素每少量在一个时间。而不是重覆操作序列为每控制方式, 序列的一个表示法被使用。方式开关逻辑确定适当的时候送proceed 命令给操作序列。冲突验查员控制模块的主函数是通过命令从操作序列和人工式模块对适当的机器控制 模块 。它得以进入对机器的数据库的模块定义, 和可能使用那些检查非法导致机械干涉的命令。由于明确定义的接口对低级机器控制模块, 冲突验查员的设计能做使用高级控制命令。细节物理I/O 被处理在机器控制模块。如上所述, 各个控制模块代表由接受某一语言的一台有限状态机 (是允许的) 的事件顺序。我们显示了那以一些明确定义的条件在这些语言并且模块连接, 整体控制结构能被保证是无曲度 8 ; 列举联合的逻辑控制器的可能的序列, 会是不切实际的, 不要求被证明。Fig.11. 操作序列模块, 显示整体序列操作和事件。接口对模块被显示在表12 。重新设置命令可能在任何时候被接受; 只一些事件踪影被简单显示。错误事件踪影也被从图中省去。 Fig.12. 操作序列控制模块的结构图, 显示接口和共有的事件。由模块接受 的事件用斜体字表现;与上层模块共有的事件是其余的。IV.组合机床在库中的机床模块可能会在许多不同的机床设计被使用。控制模块联系的各个机器模块将被合并到整个机床的控制设计过程中各个模块在他们被联系之前都能够被独立地测试，因此通过变短设计循环周期和舷梯时间，机床模块库中的控制模块可能极大减少一个新用机床制造系统的前置时间。因为零件的改变(譬如显示在上图1中的V6和 V-8 气缸盖), 机床结构将需要重新构造, 或增加一根轴或改变主轴。当这类型重组发生,需要被对操作序列控制模块和冲突验查员做变动(如果新机械干涉产生的话) 。由于他们拥有一个明确定义的接口, 每个单独控制模块都能够被独立地更换成其他模块。只要被重新设计的控制模块也有同样的离散接口, 最终的系统被保证是囊中之物。例如, 摩擦报偿控制算法也许会添加在滑台控制模块上。这会增加那个模块的表现力, 但在低级模块之中肯定会有些许的变动。V. 结论和展望历史上, 机床设计是经验所得 。在此次研究中, 我们描述了一个数学依据为组合的综合评估机床以及和他们伴生的控制器。这种研究工作列举两个机床配置的产生和模件控制设计。系统的设计过程从用机器制造的要求开始。机床综合的被提出的理论是允许机器模块库是预先完成并且存放在数据库, 独立性与控制器并且准备被使用在任一个机器设计。该理论要保证所有运动学上可实行的不同的配置系统分别被列举，以便减少错过一个好设计的机会。我们已经开发了一个基于Java 项目的自动化机床设计过程;当前任务是合并控制设计程序在已有的框架之内。我们还扩展当前可用机床和控制模块库以及形式上抽象从连续多变的控制到离散领域。鸣谢作者衷心地感谢各方支持和参加了这个项目的ERC工业成员无私的反馈 。MEAM 毕业生Eric Endsley, Morrison Lucas和Yong-Moon对工作的贡献已被描述在文中。References1 F.-C. Chen and H.-S. Yan. Configuration synthesis of machining centres with tool change mechanisms. International Journal ofMachine Tools and Manufacture, 39(2):273-295, February 1999.2 I.-M. Chen. Theory and Application of Modular ReconfigurableRobot Systems. PhD thesis, California Institute of Technology,1994.3 Y. Koren. Reconfigurable machining systems: Vision with examples.ERC/RMS #19, University of Michigan, January 1999.4 Y. Koren and A. G. Ulsoy. Engineering research center for reconfigurable machining systems. .5 S. Kota. A methodology for automated design of reconfigurablemachine tools. In ERC/RMS: Annual Report, pages35-40.Universityof Michigan, 1999.6 R. Kumar and V. K. Garg. Modeling and Control of LogicalDiscrete Event Systems. Kluwer Academic Publishers, 1995.7 C. Ling, S.-Y. Sung, T. M. L. Olsen, and D. Yip-Hoi. Systemlevel process planning for RMS. ERC/RMS #24, University ofMichigan, 1999.8 M. R. Lucas, E. W. Endsley, and D. M. Tilbury. Coordinatedlogic control for reconfigurable machine tools. In Proceedings ofthe American Control Conference, pages 21072113, 1999.9 Y.-M. Moon and S. Kota. Generalized kinematic modelingmethod for reconfigurable machine tools. In Proceedings ofthe ASME Design Engineering Technical Conferences, Atlanta,September 1998.10 Y.-M.Moon and S. Kota. Design of recongurable machine tools.ASME Journal of Manufacturing Systems, 1999. Submitted.11 R. M. Murray, Z. Li, and S. S. Sastry. A Mathematical Introduction to Robotic Manipulation. CRC Press, 1994.12 M.-A. Ouyang, C. Yi, C. Li, and J. Zhou. Intelligent layout formodular design of machine tools. SPIE, 2620:547-552, 1995.13 S. Owen, M. C. Bonney, and A Denford. A modular reconfigurable approach to the creation of flexible manufacturing cellsfor educational purposes. Institute of Electrical Engineers, Colloquium Digest, 1(174):1-13, October 1995.14 G. Pahl and W. Beitz. Engineering Design. Springer-Verlag,New York, 1984.15 C. J. J. Paredis and P. K. Khosla. Synthesis methodology for task based reconfiguration of modular manipulator systems. In Proceedings of the International Symposium on Robotics Research pages 2-5, 1993.16 G. G. Rogers and L. Bottaci. Modular production systems: anew manufacturing paradigm. Journal of Intelligent Manufacturing,8:147-156, 1997.17 H. Shinno and Y. Ito. Structural description of machine tools- 1. Description method and some application. Bulletin of theJSME, 24(187):251-258, January 1981.18 H. Shinno and Y. Ito. Structural description of machine tools- 2. Evaluation of structural similarity. Bulletin of the JSME,24(187):259-265, January 1981.19 H. Shinno and Y. Ito. A proposed generating method for thestructural configuration of machine tools. In ASME Winter Annual Meeting, 1984. ASME paper 84-WA/Prod-22.20 H. Shinno and Y. Ito. Computer aided concept design for structural configuration of machine tools: Variant design using direct graph. ASME Journal of Mechanisms, Transmissions, an Automation in Design, 109:372-376, September 1987.21 H.-S. Yan and F.-C. Chen. Configuration synthesis of machiningcenters without tool change arms. Mechanism and MachineTheory, 33(1-2):197-212, 1998.任务书课题依据:1、 零件图2、 年产量6万件3、 采用液压机构定位夹紧 4、 机床电液控制任务要求:1、 调研报告(2000字报告)一篇；2、 翻译课题相关外文资料5000(汉)字以上，两篇；3、 加工工序图、专用夹具结构设计及夹具装配图4、 加工示意图、机床联系尺寸图、生产效率计算卡5、 多轴箱装配图6、 机床液压原理图7、 PLC控制图设计8、 设计说明书2万字以上；毕业设计(论文)进度计划:起 讫 日 期工 作 内 容备 注3.26.宣布毕业设计任务，调研阅读资料；翻译外文资料调查研究、分析课题、整理调研报告工艺方案确定，绘制工序图、加工示意图、后续工作中主要技术参数确定绘制机床联系尺寸图、生产效率计算卡多轴箱设计机床液压原理图、PLC控制图设计撰写设计、计算说明书、答辩准备毕业答辩1周1234100.5Integrated Machine and Control Designfor Reconfigurable Machine ToolsD. M. Tilbury and S. KotaEngineering Research Center for Reconfigurable Machining SystemsDepartment of Mechanical Engineering and Applied MechanicsThe University of MichiganAnn Arbor, MI 48109-2125tilbury,kotaAbstract In this paper, we describe a systematic designprocedure for reconfigurable machine tools and their asso-ciated control systems. The starting point for the design isa set of operations that must be performed on a given partor part family. These operations are decomposed into a setof functions that the machine must perform, and the func-tions are mapped to machine modules, each of which hasan associated machine control module.Once the machineis constructed from a set of modules, the machine controlmodules are connected. An operation sequence control mod-ule, user interface control module, and mode-switching logiccomplete the control design. The integration of the machineand control design and the reconfigurability of the resultingmachine tool are described in detail.I. IntroductionIn todays competitive markets, manufacturing systemsmust quickly respond to changing customer demands anddiminishing product life cycles. Traditional transfer linesare designed for high volume production, operate in a fixedautomation paradigm, and therefore cannot readily accom-modate changes in the product design. On the other hand,conventional CNC-based “flexible” manufacturing systemoffer generalized flexibility but are generally slow and ex-pensive since they are not optimized for any particularproduct or a family of products.An effort at the University of Michigan aims to developthe theory and enabling technology for reconfigurable ma-chining systems 3, 4. Instead of building a machiningsystem from scratch each time a new part is needed, an ex-isting system can be reconfigured to produce the new part.In this paper, we describe how an integrated machine andcontrol design strategy can result in machine tools whichcan be quickly and easily configured and reconfigured.In order to provide exactly the functionality and capac-ity needed to process a family of parts, RMTs are designedaround a given family of parts. Given a set of operationsto be performed, RMTs can be configured by assemblingappropriate machine modules. Each active module in thelibrary has a control module associated with it. As the me-chanical modules are assembled, the control modules willbe connected and the machine will be ready to operate.Extensive and time-consuming specialized control systemdesign will not be required. Section II describes how themachine is designed from a set of basic machine modules,This research was supported in part by the NSF-ERC under grantnumber EEC95-92125.connected in a well-defined fashion, and Section III de-scribes how the control is similarly assembled from a li-brary of control modules.This modular construction ofthe machine and control allows for many levels of reconfig-urability as described in Section IV. The paper concludeswith a description of future work in Section V.II. Machine DesignOngoing work on manufacturing system configuration atthe University of Michigan addresses the problem of start-ing from a part (or part family) description and extractingthe machining operations necessary to produce the part(s)7. The operations are grouped according to tolerance, or-der of execution, and desired cycle time of the system, withthe intention that each operation “cluster” can be producedon a single machine tool. The operation cluster consideredhere is to drill a set of holes for the cam tower caps on V6and V8 cylinder heads shown in Figure 1. The input to thereconfigurable machine tool design procedure is the cutterlocation data generated by a process planner for this oper-ation cluster. Figure 2 shows sample data which includespositioning and drilling information.The RMT design procedure consists of three main stages:task clarification, module selection, and evaluation 14.After a brief literature review, these three stages will beoutlined in this section.A. Related researchSince reconfigurability is a relatively new concept in ma-chining systems, there is little, if any, published literatureon the design of reconfigurable machine tools. However,modular machine tools have been on the market for sev-eral years, and some of the published articles on modularrobots, modular machines and assembly do have some rel-evance to the design of reconfigurable machine tools. Forexample, Shinno and Ito 17, 18, 19, 20 proposed amethodology for generating the structural configuration ofmachine tools. They decomposed the machine tool struc-tures into simple geometric forms: e.g. boxes, cylinders,etc. Yan and Chen 21, 1 extended this work to the ma-chining center structural design. Ouyang et al. 12 adaptedItos method for modular machine tool synthesis and de-veloped a method for enumerating machine tool modules.Paradis and Khosla 15 determined the modular assemblyconfiguration which is optimally suited to perform a specific(a) V6 cylinder head(b) V8 cylinder headFig. 1.Two sample parts. The operation to be performed is to drillthe positioning holes for the cam tower caps. On the V8 engine,there are two such positioning holes located in a line. On the V6engine, there are eight holes in an array.PARTNO/DOHC25M2?UNITS/MMPPRINT/OPERATION CATEGORY & TYPE: Hole Making Ream?PPRINT/OPERATION NUMBER & NAME: Operation-1?PPRINT/TOOL IDENTIFIER: Drill6mm?PPRINT/POST TOOL ID: 0?PPRINT/TOOL DESCRIPTION: ?PPRINT/TOOL STATION NUMBER: 1?MODE/MILLMULTAX/OFFLOADTL/0, IN, 1, LENGTH, 0.000000, OSETNO, 0CUTTER/6, 0.79375LINTOL/0.050000SPINDL/1910.000, RPM, CLWFEDRAT/0.127000, MMPRCOOLNT/FLOODCYCLE/DRILL, 20.500000, MMPR, 0.127000, 3.020144, RAPTO, 2.020144, DWELLGOTO/0.000000, 0.000000, 0.000000CYCLE/OFFCOOLNT/OFFPPRINT/OPERATION CATEGORY & TYPE: Hole Making Ream?PPRINT/OPERATION NUMBER & NAME: Operation-2?PPRINT/TOOL IDENTIFIER: Drill6mm?PPRINT/POST TOOL ID: 0?PPRINT/TOOL DESCRIPTION: ?PPRINT/TOOL STATION NUMBER: 1?MODE/MILLMULTAX/OFFLINTOL/0.050000SPINDL/1910.000, RPM, CLWCOOLNT/FLOODCYCLE/DRILL, 20.500000, MMPR, 0.127000, 3.020144, RAPTO, 2.020144, DWELLGOTO/0.000000, -43.000000, 0.000000Set-upToolPositionFig. 2.Sample sequence of operations (cutter location) data fordrilling holes in the parts shown in Figure 1.The CL file isgenerated from a CAD package (such as IDEAS) and includesthe locations of the holes to be drilled along with the spindlespeed, feedrate, and coolant information.task. Chen 2 addressed the problem of finding an optimalassembly configuration for specified tasks; his procedurewas based on the assembly incidence matrix and employeda genetic algorithm to solve the optimization problem. Onthe systems front, Rogers and Bottaci 16 discussed thesignificance of reconfigurable manufacturing systems, andOwen et al. 13 developed a modular reconfigurable man-ufacturing system synthesis program for educational pur-poses.In our work, traditional methods of motion representa-tion and topology (i.e. screw theory, graph theory, etc.) areemployed to capture the characteristics of RMTs. Thesemathematical schemes are used for topological synthesis,function-decomposition, and mapping procedures; detailscan be found in 9.B. Task clarificationThe design of an RMT begins with task clarification,which entails analyzing the cutter location data to deter-mine the set of functions which are necessary to accom-plish the desired kinematic motions. There are three steps.First, graphs are generated which abstractly representationPos i t i onFeedSpi ndl eCool antt1t2t3t4t5t6t7t8Fig. 3.High-level operation sequence, showing causal dependenciesand concurrencies. This abstract representation of the sequenceof operations is derived from the CL data shown in Figure 2, andwill be used to design the sequencing control.the motions. These graphs are then decomposed into func-tions, and finally the functions are mapped onto machinemodules which exist in the library.A graph representation of the machine tool structureallows for systematic enumeration of alternate configura-tions and also provides a method of identification of non-isomorphic graphs. The graph representation is also usedfor bookkeeping to assign machine modules to the graphelements. A graph consists of a set of vertices connectedtogether by edges. In using a graph as an abstract represen-tation of a machine tool structure, we define two differenttypes of vertices: type 0 and type 1. A vertex representsa physical object with two ports; each port represents thelocation on the object where it can be attached to a neigh-boring object. A type 0 vertex has input and output portsthat are in-line with respect to each other, whereas a type 1vertex has input and output ports that are perpendicularto each other. Machining tasks are also classified as type 0or type 1, depending on whether the tool is parallel or per-pendicular to the workpiece.Figure 4 shows a graph for a type 0 task. Four type 1vertices are combined with several type 0 vertices to createa machine structure in the form of a C. Because type 0vertices dont change the orientation, they can be used asspacers in various combinations.The root vertex repre-sents the base or bed of the machine tool. The choice ofthe root vertex is not unique; different choices will resultin distinct machine tool designs. Structural functions areassigned to the vertices of the graph; kinematic functions(where needed) are assigned to the edges.For instance,Figure 4 shows one example of how translational motions inthe X,Y and Z directions can be assigned to graph edges,representing relative motion between the physical objectsrepresented by the two vertices of the edge.The basic functionality of a machine tool is described bythe kinematic motion between the tool and the workpiece.These kinematic functions will be represented by a homoge-neous transformation matrix 11; the desired functionalityof the machine tool will be encoded in the matrix T. Themotions necessary to carry out a given machining task arederived from the sequence of operations. The process fileshown in Figure 2 contains tool positions and motions in aCartesian coordinate system. For example, the first motion101010100 Type 0TZ?TaskTY?TX0BEDFig. 4.An graph representing a machine tool structure. Transla-tional motions (TX,TY,TZ) are assigned to edges of the graph;the vertices have structural functionality.Milling & Drilling?Spindle?Feeding?Positioning?Tool Rotation?Translation?XTranslation?YTranslation Z?Translation Z?Merge?Motor?Lead Screw?Motor?Lead Screw?Motor?Lead Screw?Motor?Power Train?Fig. 5.Function decomposition template.can be extracted as:P1=10000101000012500001F1=10000101000012000001where P1represents the position and orientation of the toolfor the positioning task, and F1represents the feed motion.From the transformation between any two adjacent posi-tions, the motion description can be extracted:M1=P11F1=10000100001500001The other motion descriptions are extracted similarly.Corresponding to each type of machining operation, atemplate is retrieved as a starting point in identifying vari-ous kinematic functions necessary to carry out the machin-ing task. For instance, the template for milling and drillingoperations show that kinematic functions are necessary forspindle revolution, tool feeding and tool positioning. Byusing this template, together with the exact feeding andthe positioning information given in the process plan, wecan derive the exact set of kinematic functions that are nec-essary such as tool rotation, translations X,Y , and Z forfeeding and translation Z for tool positioning as depictedin Figure 5.Each of the kinematic functions identified in the functiondecomposition stage is mapped to an edge of the graph asdescribed above. Assigning the functions to different edgesFig. 6.The structural graph of Figure 4 can be realized by manydifferent choices of modules.100001010011000001Fig. 7.Representation of a machine module. The CAD model ofa slide for a modular machine tool is shown on the left, and itstransformation matrix is shown on the right.can generate multiple solutions. Because purely transla-tional motions are commutative, their order in the graphcan be interchanged. In function mapping, the importantinformation is the topology of screw motions (includingpure rotational motions) and the topology of the bed.C. Module selectionCommercially available modules are selected from themodule library for each of the functions (structural as wellas kinematic) that were mapped to the graph in the taskclarification stage.The data stored for each module inthe library includes the homogenous transformation matrixrepresenting its kinematic or structural function, the twistvector supplemented by range of motion information, acompliance matrix representing the module stiffness, mod-ule connectivity information, and power requirements (foractive modules such as spindles and slides).The first step in module selection is to compare the ho-mogeneous transformation matrices of the modules withthe task requirement matrix such that when appropriatemodules are selected to meet the task requirements, theproduct of all module matrices should be equal to the de-sired task matrix: T = T1T2Tn. Again, there may bemany possible choices of modules for a given structuralconfiguration. Figure 6 shows how different slides, spin-dles, and structural elements can be assembled accordingto the graph of Figure 4.A slide module, with its CAD model and transforma-tion matrix, is shown in Figure 7.It is capable of onedirection of linear motion, indicated by the 1variable inits transformation matrix. Its database entry, shown in Ta-ble I, stores not only its transformation matrix but also themanufacturer name, model number, initial position, powerlevel, and motion data. The twist vector is augmented byinformation on the minimum, initial, and maximum dis-placement of the module.TABLE IDatabase information and documentation for the machinemodule shown in Figure 7.ManufacturerSUHNERModel NameUA 35-ACInitial Position100001000011000001Twist vector000010TRange of motion1550155Max. force5500NCompliance matrix,Etc.Power requirements,Connectivity information, .(a) V6 machine(b) V8 machineFig. 8.Reconfigurable machine tool designs for the two differentparts.D. EvaluationOnce a set of kinematically-feasible modules have beenselected, the resulting machine design must be evaluated.The criteria for evaluation of the reconfigurable machinetools synthesized by the above systematic procedure in-clude the work envelope, the number of degrees of freedom,the number of modules used, and the dynamic stiffness.The number of kinematic degrees of freedom of the ma-chine tool must be kept to a minimum required to meetthe requirements, both to reduce the actuation power andminimize the chain of errors. Each active Examples showthat the designs generated by this methodology have ex-actly the number of degrees of freedom necessary to per-form the required machining operations on the given part10. Machine tool designs which are generated using thismethodology for the example parts of Figure 1 are shownin Figure 8.The resulting designs must be evaluated with respect tothe expected accuracy. The stiffness of the entire machinetool, one of the most important factors in performance, isestimated based on the module compliance matrices andthe connection method.III. Control DesignAs the machine is built from modular elements, so isthe control.In this work, we focus on the logic controlX - AxisOperationSequenceUserInterfaceManualModeModeSwitcherAutoModeConflictCheckerSpindleY - AxisFig. 9.The overall structure of the modular control system.for sequencing and coordination of the machine modules;a discrete-event system formalism is used 6. There is onecontrol module associated with each active machine mod-ule; we refer to these as machine control modules. In themachine design, there are passive elements which connectthe active elements together. In the control design, theremust also be “glue” modules which connect the machinecontrol modules.The overall architecture of the controlsystem for an RMT is shown in Figure 9. The structure issimilar for either of the two machines shown in Figure 8;for the V8 machine, there is no Y -axis control module.As shown, the machine control modules are at the lowestlevel; these interact directly with the mechanical system.The user interface control module is at the highest level, in-teracting with the user through pushbuttons and a display.The operation sequence control module is defined based onthe high-level operation sequnce for the part as shown inFigure 3. Three modules handle the mode switching logic.In this section, we briefly describe each of these types ofcontrol modules as well as their interaction and coordina-tion.A. Machine control modulesEach machine control module has a well-defined interfacespecification: it accepts discrete-event commands from agiven set, and returns discrete-event responses from a givenset. Within the control module will be all of the continuous-variable control, such as servo control for axes. This con-tinuous control is designed using standard PID algorithmsand the axis parameters such as inertia, power, lead screwpitch, which come from the machine module definition. Inaddition, each machine control module will contain con-trols for any machine services associated with the machinemodule, such as lubrication or coolant.Thus, each ma-chine control module is a self-contained controller for themachine module it accompanies, and can be designed andtested independently of the rest of the machine.The design of a machine control module must be doneSlide ControllerMove to x CommandDoneStop CommandDoneJog in Positive x CommandDoneJog in Negative x CommandDoneCI1.MV(x)/ CO1.MV(X)RO1.DN /RI1.DN/ CO1.STRO1.DN /RI1.DNCI1.STCI1.JP/ CO1.JPRO1.DN /RI1.DNCI1.JN/ CO1.JNRO1.DN /RI1.DNFig. 10.Slide Controller. The slide controller includes (within theboxes) the servo controller for a slide. When the slide has reachedthe commanded position to within some tolerance, a “done” re-sponse is returned.only once for each machine module in the library. When-ever the machine module is used in a machine design, thecontrol module can be used in the associated control de-sign. The control module may be used independently, withits own processing power, I/O and a network connection tothe rest of the control system, or it may be used as a pieceof the overall machine controller which is implemented ina centralized fashion.An example of a machine control module for a slide isshown in Figure 10. There are four commands that themodule can accept: move to a position x, stop, jog in posi-tive x, and jog in negative x direction. When it has finishedthe desired operation, it returns the “done” response. Awatchdog timer is included (but not shown); if a prespec-ified amount of time elapses and a done response has notbeen issued, an “error” response will be returned.B. Operation sequenceThe operation sequence module is defined from the high-level sequence extracted from the cutter location datashown in Figure 3.The main structure of this controlmodule is a sequence of states representing the sequenceof operations that must be performed on the part; waitstates are included at the completion of each step. Fig-ure 11 showns the operation sequence module for the ma-chine of Figure 8(b) and the operation sequence of Figure 3.Simple error handling which merely passes the error up tothe user interface is incorporated in the design but is notshown in the figure for simplicity. If a “reset” commandis received, the spindle is turned offand the slide is resetto its home position. The operation sequence for the V6machine is similar, but has more operations because thereare two linear axes that need to be sequenced. As shown inthe overall structure of Figure 9, there are two ports to theoperation sequence control module: one connects to theAuto Mode control module, and another connects to theconflict checker. The interface to the operation sequencecontrol module is shown in Figure 12.proceed/?moveX(p1)doneX/?ccproceed/?spindle_ondoneS/?ccproceed/?spindle_feeddoneS/?ccproceed/?spindle_offdoneS/?ccproceed/?moveX(p2)doneX/?ccproceed/?spindle_ondoneS/?ccproceed/?spindle_feeddoneS/?ccproceed/?spindle_offdoneS/?part_completeIDLEreset/?moveX(p0)reset/?moveX(p0)reset/?spindle_offreset/?spindle_offreset/?spindle_offreset/?spindle_offreset/?spindle_offdoneS/?moveX(p0)doneX/?ccFig. 11.Operation sequence module, showing the overall sequenceof operations and events. The interface to the module is shownin Figure 12. The reset command can be received at any time;only some of the event traces are shown for simplicity. The errorevent traces are also omitted from the figure.cc (command_complete)?part_complete?errordoneS?errorS?doneX?errorXproceed?resetmoveX(p)?spindle_on?spindle_off?spindle_feed?Operation?SequenceFig. 12. The block diagram of the operation sequence control module,showing the ports and shared events.Events received by themodule are in italics; events shared with the upper-level moduleare in bold face.C. Modular control structureThe user interface control module interacts with the userthrough a set of pushbuttons to turn the control systemon and off, switch between control modes, and single-stepthrough the operation sequence. Its main functions are topass the user commands through to the rest of the con-troller, and to display the current state of the machine tothe user.Machine tool controllers have several different modes. Inthe auto mode, the operation sequence executes continu-ally; another mode may execute the operation sequenceonly once. In step mode, a pushbutton command must beused to initiate every step of the operation sequence, andin manual mode, finer control is available through jog com-mands that move the active elements a small amount at atime. Instead of repeating the operation sequence for everycontrol mode, one representation of the sequence is used.The mode-switching logic determines the appropriate timesto send the “proceed” event to the operation sequence.The main function of the conflict checker control moduleis to pass the commands from the operation sequence andmanual mode modules to the appropriate machine controlmodule(s). It has access to the database of the machinemodule defintions, and can use those to check for illegalcommands which would result in mechanical interferences.Because of the well-defined interface to the low-level ma-chine control modules, the design of the conflict checkercan be done using high-level control commands. The de-tails of the physical I/O are handled in the machine controlmodules.As described above, each control module is representedby a finite state machine which accepts a certain language(sequences of events which are allowable). We have shownthat with some well-defined conditions on these languagesand the module connections, the overall control structurecan be guaranteed to be deadlock-free 8; enumerating allpossible sequences of the combined logic controller, whichwould be impractical, is not required for verification.IV. Reconfiguration PropertiesThe machine modules in the library can be used in manydifferent machine designs. The control module associatedwith each machine module will be incorporated into thecontrol design of the overall machine. This library of ma-chine and control modules can significantly reduce both thelead time of a new machining system, by shortening the de-sign cycle, and the ramp-up time, since each module canbe tested independently before they are connected.For some part changes (such as between the V6 andV8 cylinder heads shown in Figure 1), the machine toolwill need to be reconfigured, perhaps by adding an axis orchanging the spindle. When this type of reconfigurationoccurs, changes need to be made to the operation sequencecontrol module and the conflict checker (if new mechanicalinterferences are created).Because they posess a well-defined interface, each indi-vidual control module can be changed independently of theothers. As long as the redesigned control module has thesame discrete-event interface, the resulting system is guar-anteed to be deadlock free. For example, a friction com-pensation control algorithm may be added to one of theslide control modules. This would increase the performanceof that module, but the only changes necessary would bewithin the lowest-level module.V. Conclusions and Future WorkHistorically, machine tool design has been experience-based. In this research, we described a mathematical ba-sis for synthesis and evaluation of Reconfigurable MachineTools and their associated controllers. This research workhas addressed both the generation of machine tool configu-rations and modular control design. The systematic designprocess begins with the machining requirements.The presented methodology for synthesis of machinetools allows a library of machine modules to be pre-compiled and stored in a database, self-contained with con-trollers and ready to be used in any machine design. Themethodology also ensures that all kinematically viable and
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