【作者】 董天阳；

【导师】 董金祥； 童若锋；

【作者基本信息】 浙江大学 ， 计算机应用技术， 2005， 博士

【摘要】 作为敏捷制造、虚拟制造等先进制造技术中的一项关键技术,装配规划技术满足企业快速响应市场需求的变化,近年来受到了学术界和工业界的广泛关注。智能装配规划不仅能够提供一种系统搜索满意装配工艺的手段,而且提供了能够按照可装配性、可维护性、可用的装配资源以及整个装配成本的高低等要求,对产品进行优劣分析的一种有力工具。装配规划通过产品的CAD模型,在计算机上创建近乎实际的虚拟环境,以便对产品的装配过程进行模拟与分析,在产品的研制过程中及时对装配方案进行快速评价,预估产品的装配性能,及早发现潜在的装配冲突与缺陷,并将这些装配信息反馈给设计人员,让其尽早发现错误,及时修改,从而优化产品装配过程。运用这样的技术,可摈弃传统设计的物理样机而代之以电子样机,这不但有利于并行工程的开展,而且还可大幅度降低产品设计成本。装配规划对于满足企业产品的快速开发需求和增强企业竞争力具有重要意义。 本文结合973计划子课题“面向产品创新开发的虚拟设计平台”的研究,针对大型产品结构庞大、零部件装配关系复杂的特点,对智能装配规划中涉及的若干关键技术进行了深入的研究,包括装配建模、装配序列规划和装配任务规划等。 本文的第一章主要分析智能装配规划产生的背景和研究内容,研究装配规划的产生背景和国内外发展状况,并针对现有方法存在的问题,提出基于知识的装配规划解决方案。 第二章首先建立了智能装配规划系统的体系结构,然后通过对典型装配模型的特点和装配模型的评价方法的研究,分析了Top-Down设计的基本流程,建立了支持Top-Down设计的多细节层次装配模型,提出了多细节层次装配模型的建立和信息映射算法;提出了基于联接件知识的零件信息表示方法,着重研究了支持多细节层次模型的产品信息表示方法和基于联接语义的装配建模技术。 第三章是本文的重点之一,主要对智能装配规划中的序列生成方法进行研究。本章以基于联接语义的装配模型为基础,提出了基于知识的推理和几何推理相结合的装配序列规划算法,着重研究了基于典型实例和标准实例的匹配方法和运用有向联接件知识的装配序列求解方法。根据有向联接件的装配特点,对基于联接件知识的有向图生成规则进行了深入研究; 第四章针对现有拆卸方向求解中存在的问题,通过对单位球面离散化后产生的误差与离散化的细微程度之间关系的研究,提出了基于渐变间距离散化单位球的拆卸方向求解方法和拆卸方向可行性分析方法。更多还原

【Abstract】 Assembly planning is an important componet of the advanced manufacturing technologies such as agile manufacturing, virtual manufacturing. It attracts concerns from both academic and industrial circles, because it meets the manufacturing’s need of responding to market changing fast. Assembly planning aims to identify and evaluate the different ways to construct a mechanical object from its components. The problem can be formulated as follows: given a geometrical and technological description of a product, find an assembly sequence that satisfies the precedence relations between operations and meets certain optimization criteria. With the help of assembly planning, the designers can evaluate the assembly schema conveniently during the product research and design process, to find the assembly defects and revise them as early as possible. In assembly planning, the designers analyse a product without actually making a physical prototype of the product, that means the design is not yet created in its final form but that only a geometric representation of the object is presented to the user for observation, analysis and manipulation. This virtual prototype does not necessarily have all the features of the final product but has enough of the key features to allow testing of the product design against the product requirements. Assembly planning has profound significance in meeting rapid product development (RPD) requirements, increasing global competition for industries, especially when it is a part of the concurrent engineering and computer integrated manufacturing practice.This work is supported by the Special Funds for Major State Basic Research Program (973) of China under grant 2002CB312106. Our research focuses on automatic generation of assembly sequences from assembly model and assembly task allocation according to assembly conditions.On the basis of analyzing the background and history of assembly planning, Chapter 1 reviews the state of the art in assembly planning, then points out the objective of the thesis and presents the research frame.Chapter 2 presents the architecture of KBAPS (Knowledge-based Assembly Planning System). Then it discusses the foundational theory of assembly model and how to establish it. The role of assembly model taking in planning is presented. After analyzing the typical assembly models and the process of top-down design, it presentsan approach to build the product model at multiple LOD (Levels of Detail) model and CSBARM (Connection Semantics Based Assembly Relational Model) that integrates both geometric and non-geometric assembly data.Chapter 3 is the key of this thesis. It focuses on the automatic generation of assembly sequences, there are three ways to construct plans for a CSBAT: (1) by retrieving the typical base, (2) by retrieving the standard base, and (3) by geometric reasoning. A novel approach for assembly sequence planning using directed-connector and a case-based approach to generating sequences are proposed. After analyzing the characteristics of directed-connectors, directed-connector knowledge is exploited for assembly sequence planning.In Chapter 4, a novel approach to find the feasible disassembly direction set is presented by applying discrete spherical algorithm to analyzing assembly constraints. Hie global disassembly direction is finally determined by verifying the disassembled part being free from interference on its removal path.Chapter 5 presents an approach for cooperative assembly task planning for a multiple manipulators environment to improve the flexibility and reliability of the automated assembly system. The outline of the agent-based and cooperative assembly task planning system is presented. For the sake of mmirnizing the makespan, the algorithm of task planning takes into account not only the assembly processing time but also the time needed for the manipulators to change tools.In chapter 6, Some applications of assembly planning are described to verify the validity of the algorithm.In chapter 7, all achievements of the thesis are summarized and the future research work is sketched out.更多还原