【作者】 张书亭；

【导师】 高曙明；

【作者基本信息】 浙江大学 ， 计算机科学与技术， 2009， 博士

【摘要】 复杂机械产品的设计具有两个重要特点,一是采用自顶向下的设计方式,另一个是多人参与、协同完成。然而,目前CAD系统仍难以支持自顶向下、多人协同的产品设计。鉴于多人协同的产品自顶向下设计的高度复杂性,作为研究的第一步,我们将当前工作集中在概念设计完成之后的协同产品设计,即一组设计者根据概念设计结果,协同地、由抽象到具体地完成产品设计。论文的主要工作包括以下几个方面:1.提出一个自顶向下协同产品设计框架。我们将自顶向下协同产品设计过程分成布局设计、协同骨架设计、协同详细设计三个设计阶段,并基于该设计过程的需求,设计了自顶向下协同产品设计的六个主要功能:基于符号的布局设计,耦合结构参数协同计算,协同装配建模,协同特征建模,基于Agent的变动传播,基于多媒体会议的协商交流。2.提出一个支持自顶向下协同产品设计的多层次分布式装配模型。该装配模型总体上分为布局装配模型、骨架装配模型、详细装配模型三个主要层次,以支持自顶向下产品设计;采用在服务器和客户端的复制式分布表示,以支持分布式协同设计。在分布式表示中,服务器端为完整的产品装配模型,客户端装配模型基于协同设计需要动态装载,具体包括设计者负责设计的子装配或者零部件的模型信息,以及和其具有装配关系的其他设计者负责设计的子装配和零部件信息。为支持装配模型对象在各个站点的一致,采用了局部ID和全局ID的对象命名机制。3.提出一种支持自顶向下协同产品设计中耦合结构参数协同计算的方法。该方法基于模糊理论表示设计早期阶段的模糊设计参数,通过效用函数表示设计者基于设计经验确定的设计参数不同数值的优先程度,由设计者协同建立以效用为目标的优化模型,并通过改进的遗传算法进行优化求解。4.提出自顶向下协同产品设计中基于Agent(智能体)的变动传播方法。通过服务器和客户端Agent之间的协作,动态监控协同设计系统中各个站点对装配模型的变动修改,然后由服务器端Agent基于特征变动、装配约束变动、工程约束变动的推理以及层次变动推理,确定装配模型对象的变动以及分布,最后以命令的方式更新所有相关站点的装配模型,保证变动操作后分布式装配模型的一致性。5.基于上述理论方法实现了支持自顶向下协同产品设计的原型系统CTDAD。该系统采用复制式服务器-客户端体系结构,核心功能模块包括布局设计、耦合结构参数协同计算、特征造型器、装配建模、变动传播Agent、ID管理、协商管理等。使用该系统,完成了一个液压式机械手的自顶向下协同产品设计,对本文所提出的框架与方法进行了验证。更多还原

【Abstract】 There are two important characters for complex mechanical product design, one is that it is usually carried out in a top-down manner; the other is that it is generally accomplished collaboratively by several teams or designers. However, it is difficult for traditional CAD systems to support the collaborative top-down product design. Because of the complexity of the collaborative top-down product design, as the first step, our research now focuses on the collaborative product design that is right after the concept design which means that a group of designers collaboratively fulfill the product design from abstract to detail.The main works of the dissertation is presented as follows:1. A framework is proposed for the collaborative top-down product design. We divide the collaborative top-down product design into three phases including layout design, collaborative skeleton design and collaborative detail design. Based on its requirements six functions are proposed for the collaborative top-down product design which are symbol based layout design, calculation of coupled structural parameters, collaborative assembly modeling, collaborative feature modeling, agent based variation propagation and multimedia conference based negotiation.2. A hierarchical and distributed product assembly model is presented. The assembly model contains three levels which are layout assembly model, skeleton assembly model and detail assembly model. The assembly model is distributed on the clients and server in replication mode. The assembly model on the server is a complete assembly model including the whole assembly model information. The client assembly model is dynamically loaded according to the designer’s design information requirement, which includes both the information of the subassemblies or parts undertaken by the designer and those having assembly relationships with the subassemblies or parts. A naming mechanism that contains global IDs and local IDs is proposed to ensure the object IDs of distributed assembly model to be consistent all over the distributed system.3. A method is proposed to support the collaborative calculation of the coupled structural parameters. The fuzzy design parameters are represented based on fuzzy theory. Utility function is used to represent the priority of the different values of a parameter which is determined by the designers according to their design knowledge and experiences. The designers collaboratively establish the optimization model taking the utility as the target. Genetic algorithm is adopted to solve the optimization model.4. An agent based approach is presented for addressing design variation propagation during collaborative top-down product design. The assembly model changes are automatically monitored through the interaction and cooperation of the agents located at the clients and the server. The changes and distributions of the related distributed assembly model are figured out by the agent located at the server through the reasoning of engineering constraint variations, feature variations, assembly constraint variations and hierarchical variations. Based on the reasoning result the distributed assembly model of the related clients and the server are updated in a command based mechanism, which ensures the consistency of the distributed assembly model.5. A prototype named CTDAD is implemented based on the proposed research. The system adopts replicated client-server architecture and contains the following kernel functional modules: layout design, collaboration calculation of coupled structural parameters, feature modeling, assembly modeling, variation propagation agent, ID management, negotiation management. Base on the CTDAD, the collaborative top-down product design of a manipulation is accomplished to verify the framework and method proposed in the paper.更多还原