【作者】 赵晓峰；

【导师】 赵正旭； 周以齐；

【作者基本信息】 山东大学 ， 机械电子工程， 2010， 博士

【摘要】 虚拟制造技术因能在产品实际制造之前,在计算机中模拟产品生产制造的不同过程,从而及时发现问题,优化生产,避免重大失误,而受到广泛重视。虚拟制造系统有两种开发途径,其中在虚拟现实VR平台上定制开发专用的虚拟制造系统的方法,由于能够满足企业多方面的复合需求,而应用广泛,但这种途径的开发难度较大。本文通过分析指出数据模型、规范的接口文件、仿真工具是影响虚拟制造系统开发效率的重要因素。为提高虚拟制造系统的开发效率,本文提出在VR平台之外应设计一个虚拟制造通用平台,由该平台定义规范的数据模型,并提供规范接口和仿真工具。另外,虚拟制造系统在表达制造相关数据时,没有规范数据模型可以参照,在数据共享时,缺乏产品制造信息规范。本文通过分析指出,要实现虚拟制造系统的快速创建与数据共享,就有必要对制造数据进行规范化研究。在虚拟制造通用平台的很多研究内容中,本文在分析了通用平台的功能定位和模型构成的基础上,选择通用平台的形式化开发方法、制造模型的形式化描述、制造模型的数据规范化作为本文研究的重点内容。在工具选择上,由于形式化方法与面向过程和面向对象两类方法相比,在系统及数据的描述方面更严谨、准确、清晰,因此,本文研究如何使用形式化方法开发虚拟制造系统平台,并进行相关数据的形式化规范研究。通过综合分析和总结规范化方法的步骤和工具,本文提出了虚拟制造通用平台制造数据的规范描述方案,利用Z语言形式化地描述了与制造相关的产品、资源和过程模型,并在此基础上采用基于元模型的规范化技术对相关数据进行了文本设计。本文提出的虚拟制造通用开发平台,有助于形成一种新的虚拟制造系统开发模式或构建途径,能够降低虚拟制造系统的开发难度；其次,形式化方法的使用利于开发出高稳定性、高可靠性的虚拟制造系统；而且,形式化描述和规范化设计的结果,可以实现虚拟制造通用开发平台的数据规范化,有助于实现不同系统间的数据共享,对虚拟制造系统的开发和系统集成有重要的指导意义和应用价值。完成的主要研究工作包括：(1)研究了基于Z语言的虚拟制造系统形式化描述过程,并指出了基于此形式化方法的各类虚拟制造系统的开发模式。针对面向过程和面向对象的开发方法在使用自然语言或图形符号描述系统时,可能存在冗余、错误、矛盾的现状,本文采用具有严格数学基础的形式化技术描述系统。研究了如何以集合的观点描述虚拟制造系统,按照Z语言描述的-般过程,对较高层次的虚拟制造系统进行了完整的形式化描述。并指出了在通用平台制造信息元数据的支持下,各类虚拟制造系统相似的开发模式。(2)研究了虚拟制造系统中产品模型的Z语言形式化描述技术。按照形式化方法的要求,从集合的观点,将产品模型设计为通用属性、零件、部件、拓扑关系、装配及机构约束、各种精度属性(含尺寸精度、形状位置公差、表面结构、配合等)以及各种基准等要素的集合。在分析虚拟制造系统对产品模型在显示方便性、可编辑性、工程语义等方面要求的基础上,提出了一种能够表达各种产品工程语义的产品模型。其中在几何模型部分,提出了一种CSG和B-rep相融合的基于特征的产品几何模型。该几何模型保留了现有规范对产品最终表面的描述,不改变现有规范便于显示的特点,同时增加了产品造型过程描述,并将最终状态表面与产品造型过程进行了关联,支持了对产品造型过程和加工工艺的描述。在产品模型中设计了产品特征表面层,能够支持产品装配关系的描述。在产品模型中设计增加了基准要素集合的描述,能够支持产品尺寸、形位公差、配合精度、表面结构等工程信息的描述。在装配和机构约束方面,设计了两种描述方法。一种是采用装配法描述零部件间的静态位置关系,一种是采用运动副链接法描述零部件间的动态运动约束关系。链接法通过父子构件间的位姿关系和运动关系完成构件间运动约束关系的定义,能够满足轴数不限、平动或转动方向任意的串联结构机床的机构模型表达。拓扑关系方面,解决了使用Z语言描述产品零部件间的包含关系,零件与CSG模型及B-rep模型的关联关系,以及B-rep模型内部的层次关系等关键问题。同时对于各Z语言模式中使用的类型,按照从上到下的层次顺序,逐步进行了细化描述,基本完成了一个兼顾显示、可编辑特性的,并包含制造信息的产品模型的Z语言形式化描述。(3)研究了虚拟制造系统中资源模型的Z语言形式化描述技术。从集合的观点,本文将设备资源模型设计为通用属性、构成设备的零部件集合、零部件间的拓扑关系集合、操作面板集合、操作控制关系集合、可动零部件集合、不可动零部件集合、以及功能类型等要素的集合。除去在产品模型部分已经完成的部分外,本文重点描述了设备的操作面板、操作控制过程、及功能属性。操作控制面板方面,通常根据功能和形式不同,面板组件被分为输出显示区、指示灯、动静态文本、旋钮、按钮五类,本文分别对五类组件进行了Z语言描述,并完成了操作面板模式的定义。在操作控制过程方面,采用了基于元模型建立操作控制过程模型的方法,并提出了一种设备操作控制过程元模型。该元模型定义每个操作控制过程都由标志节点、连接弧和受控运动节点三种元素构成,每个受控运动节点都包括驱动部件、从动部件、运动模式、相关数据、扇入及扇出逻辑节点共六类要素。同时本文设计了基于此元模型进行操作控制过程建模的图形描述方法。元模型的提出统一了资源操作控制过程的建模方法,使建模更简单、易于理解。在功能属性方面,根据面向生产类的虚拟制造系统需求,设计采用抽象功能、状态集、规则集简要描述各类资源的功能属性。为区分部件的运动能力,将部件分为有动力运动、有动力静止、无动力运动、无动力静止四类,同时,为区分运动能力和承载状态的不同,为部件设计了四种主从运动状态。解决了抽象功能和状态集的Z语言描述问题。(4)研究了面向生产的过程模型的Z语言形式化描述技术。从集合和状态的角度,将生产过程设计为具有相同生产方案的同种产品的制造过程模型的集合。在制造过程模型的设计中,本文在深入研究了工作流过程元模型、企业生产中的“方法研究分析技术”、及过程描述的图形工具IDEF3的基础上,提出了面向车间加工、装配的虚拟制造系统过程元模型。按照该过程元模型,一个制造过程被设计为开始节点、终止节点、任务节点、控制连接弧、单对节点运输弧、多对节点运输弧等要素的集合。每个过程模型都由子过程和过程核心元素组成,过程核心元素包括节点和连接弧,节点和连接弧都包含产品、资源、相关数据和转移条件四个要素,分别回答加工装配过程中处理什么产品、用什么设备、采用什么方式处理,处理之后产品去向哪里的问题。活动由节点表示,包括三种标志节点、七种任务节点,每种任务节点分别对应固定资源中的一个设备；连接弧两端各连接一个节点,根据是否涉及产品运输,分为控制连接弧和对象连接弧两种,对于只表达节点间顺序关系的连接,采用控制连接弧,对于除顺序关系外还涉及产品运输的,采用对象连接弧。设备资源,分为固定资源和运输资源,固定资源必须关联某任务节点,而运输资源则与对象连接弧关联。同时,借鉴活动网络图方法,本文还针对该过程元模型,设计了一种生产过程的图形描述工具,具体包括九种符号。任务节点符号的设计部分继承了工程分析中的流程程序图五要素,其中完整保留了操作、检验、暂存和存储四要素的描述符号,运输要素转由对象连接弧,另外增加了装配、合成、拆分等任务及相应符号。企业车间加工和装配过程建模的示例,验证了上述元模型的有效性。(5)进行了虚拟制造系统产品、资源、生产过程模型规范文本设计。分析了目前虚拟制造系统间可共享交换的数据少,且产品模型仅限于几何模型规范的现状。为了满足虚拟制造通用开发平台的功能需要,并实现制造系统虚拟仿真环境的快速重建与数据共享,需要对虚拟制造系统的产品、资源、过程等相关数据进行规范化研究。依据目前广泛使用的基于元模型的数据规范化方法三个步骤,第一步数据及其关系描述方面,使用了本文前面利用UML对产品、资源、过程模型的描述成果：第二步数据属性描述方面,使用了前面相关模型的Z语言描述成果;第三步共享技术研究方面,本文在参考STEP文本的基础上,设计了相关模型的规范文本。简而言之,为了提高虚拟制造系统的开发效率,从而促使虚拟制造系统的更广泛应用,有必要研究虚拟制造系统的通用开发平台,并围绕其开展相关研究。本文选择了通用平台的形式化开发方法、制造模型的形式化描述、制造模型的数据规范化作为本文研究的重点内容。给出了采用Z语言开发虚拟制造系统的一般方法和模式,采用形式化的开发方法有利于开发出高可靠性、高安全性的系统。设计了通用平台中的制造信息模型,并研究了制造信息模型的Z语言描述技术,制造模型的形式化描述有利于规范通用开发平台的数据内容。设计了制造模型共享交换的规范文本,有利于不同虚拟制造系统间的数据共享集成,以及利用通用平台快速创建虚拟制造系统。更多还原

【Abstract】 Virtual manufacturing technology was used extensively, because it could optimize product manufacturing process, and could avoid serious mistakes, before the actual manufacturing of the product, through simulating different manufacturing processes in the computer. However, because the software development of Virtual Manufacturing System (VMS) is very difficult, the application of VMS was hindered.This paper analyzed the two main building apporachs of virtual manufacturing system and reasons of their development efficiency. Then it was found that the data model, the interface specification and the simulation tools were important factors to the development efficiency.Research of Virtual Manufacturing Platform (VMP) includes many works. Based on analysis of VMP function and composition, this paper focused on formal development method, formal description and data specification of manufacturing models.No standard data model could be referred, no sharable data between different systems could be used and product model was in lack of engineering semantics. So in order to realize VMS rapid construction and data sharing, this paper thought that there was a need for standardization of manufacturing data. Compared with process-oriented and object-oriented methods, the system description according to formal method was stricter, accurater and clearer. So this paper used Z notation, a formal tool, to developt VMP and normalize the related data.Based on comprehensive analysis and summary on the specification steps and tools, this paper proposed a manufacturing-related data specification solution for VMP, and used Z notation to describe the manufacturing-related products, resources, process model, and designed related data text format according to these description.VMP proposed by this paper, will contribute to a new development mode of VMS, and will reduce the VMS development difficulty. Secondly, the use of formal methods will be helpful to the VMS development of high stability and high reliability. Moreover, the results of formal description and data specification, can realize data standardization of VMP, and can realize data sharing between different VMS. So the methods and results in this paper are valuable for VMS development and system integration.The main content of the paper is summarized as follows:(1) VMS formal description method using Z notation was studied, and a VMS development mode based on this formal method was put forward.The tools used by Process-Oriented and Object-Oriented development approach were natural language or graphical symbols, so it was possible that system description contained redundancy, errors and contradictions. For this shortcoming, this paper used formal technology, which is based on strict mathematics theory, to describe VMS. According to the general description procedure of Z, the higher level formal description of VMS at the viewpoint of set was studied. A development mode of VMS based on the manufacturing information metadata was put forward.(2) The formal specification technology of product model was studied.According to formal method, at the viewpoint of set, the product model was designed as a set, which contained general attribution, parts, assemblies, topological relationship, assembly relationship, mechanism constraint, precision and datum elements.In order to meet the demand of displayability, editability and engineering information of product model in VMS, a product model with engineering information was designed. In aspect of geometrical model, a based-feature model which combined CSG and B-rep was designed. It retained the product surface represent, added the modeling process represent, and designed a connection relation between them. The feature surface of the new product model could support the assembly relationship specification. The datum elements set could support engineering information specification, such as product dimension, form and position tolerance, fitness and surface roughness.In aspect of assembly relation, two methods were designed. One was called "assemle", which could describe the static position relationship of models, another was called "Link", which could describe the dynamic mechanism motion constraint. The "Link" method defined the motion constraint through definition of "PoseRelationship" and "MotionRelationship".In aspect of topological relationship, several key problems, such as Z specification of inclusion relation between parts and assemblies, Z specification of connection relation between CSG and B-rep, hierarchical relationship between B-rep models, were solved.Many types used in Z schema specification were defined from top to bottom.(3) The formal specification technology of resource model was studied.According to formal method, at the viewpoint of set, the resource model was designed as a set, which contained general attribution, parts and components assembly, topological relationships, control panels, operating control relations, moveable components, unmoveable components, function elements. Except for the section defined in chapter 3, abstract function, control panels and operation process specificatioin were studied.In aspect of control panel, the panel components were classified as output display, indicator, static text, turn button and button five types, according to function and form. The ControlPanel schema was defined on the basis of all components Z specification.In aspect of operation control process, a control process metamodel was put forward. According to the metamodel, all operation control processes consisted of CtrlPFlagNode, CtrlPConnector and CtrlPMoveNode three kinds of nodes. Every CtrlPMoveNode consisted of DriveAssembly, DrivenAssembly, MoveMode, RelavantData, FanIn and FanOut six elements. And a graphical tool for control process modeling was designed. The control process modeling method based on the metamodel made resource modeling easier and more understandalbe.In aspect of function specification, according to the demand of VMS face to manufacturing, resource function was designed as the abstract function, rules and states set. The assemblies were classified as ActiveMoveableAssembly, PassiveMoveable Assembly, ActiveStaticAssembly and PassiveStaticAssembly. In order to distinguish assembly ability and state, four states were designed for assembly. Thus specification problems of abstract function and state set were solved during using Z notatioin. (4) The formal specification technology of produce model was studied.According to formal method, at the viewpoint of set and state, the produce process model was designed as a set, which contained a manufacturing process for the same products with the same produce process.In aspect of manufacturing process, a manufacturing process metamodel was put forward facing to machining and assembly, based on analysis of Workflow process metamodel, "method study analysis technology" in production, and IDEF3 standard. According to the metamodel, a machining or assembly process model is a set, which consisted of StartNode, EndNode, TaskNode, ControlConnector and ObjectConnector. Every manufacturing process is made up of subprocesses and kernel elements, which contained Node and Connector. Node and Connector are both consisted of Product, Resource, RelavantData and Transition. The four composition would answer four questions respectively, that is what product was being processed, what device was being used, which way was being used and where the product would go after this process. The manufactuing activity is presented by TaskNode, which contained three FlagNodes and seven TaskNodes. And every TaskNode was corresponding to a device of FixResource. The Connector connected two nodes, and was classified ControlConnector and ObjectConnector. The ControlConnector represented the sequence of two nodes, and the ObjectConnector also represented the products transportation except for sequence. The device resources were classified as fixed resource and transport resource. The fixed resource connected a TaskNode, and the transport resource connected ObjectConnector.A graphical tool for manufacturing process modeling was designed, which is based on the activity network diagram. There were nine symbols in the graphical tool, four TaskNode symbols of which succeeded from "Flow process chart" of engineering analysis.The modeling examples of machining and assembly, proved the metamodel effectiveness.(5) The text format of product, production and produce model was designed for data sharing.VMS was in lack of shareable data, so in order to meet function demand of VMP and realize quick reconstruction and data sharing of VMS, the research work for data specification of manufacturing model was necessary.Data specification contained three steps; the first and second parts were finished by UML and Z. At the last step, a text format based on Z specification was designed.In short, in order to improve the development efficiency of VMS, it is necessary to study a VMP. This paper focuses on the formal development method, formal description and data specification of manufacturing models. A Z-based formal development method, which is helpful to high reliability and high safety system development, was put forward for VMS. This paper designed related manufacturing information model, and realized specification description by Z notation. The formal specification of manufacturing model would be beneficial to VMP. The manufacturing informatioin model text would be beneficial to data sharing between different systems, and to quick reconstruction of VMS.更多还原