计算机辅助的机构运行行为知识表示及推理

知识源于人类对对象的分类能力。机械运动系统概念设计是一个功能→行为→结构的过程,本文在用属性及属性值的方式表示机构运动行为的基础上,提出了机构系统方案设计的匹配推进过程,并用ＢＮＦ形式和生成规则相结合的方法生成机构的运动行为知识。在此基础上,给出了生成行为知识的推理流程图,可以在计算机的辅助下表示机构的运动行为。最后以一个示例说明该方法的应用。     

采煤机概念设计的知识表示与知识推理

为实现采煤机概念设计知识和经验的重用,针对采煤机设计领域知识的可分解性、多样性和模糊性等特点,提出了以面向对象为主、产生式规则为辅的知识表示方法,建立了采煤机概念设计实例库和规则库,并将基于实例和规则推理的集成推理机制应用于采煤机概念设计知识推理中.最后以UG为平台开发了采煤机概念设计系统,实现了知识驱动的采煤机概念设计自动化,积累了设计经验和知识,缩短了产品设计周期.通过工程应用实例验证了该方法的有效性与可靠性.     

数控机床设计知识库系统知识获取、表示及推理研究

依据数控机床设计知识类型复杂、知识量巨大的特点,运用自然语言理解技术与CBR技术结合建立知识获取模型,采用面向对象技术和带有阈值限制的产生式规则混合知识表示方法实现了案例库和规则库的知识表示,运用基于实例的推理(case-based reasoning,CBR)和基于规则的推理(rule-based reasoning,RBR)相结合实现了知识推理,构建了数控机床设计知识库系统.     

功能-运动行为-结构的概念设计模型及运动行为的多层表示

在机械运动系统概念设计中,引入运动行为层,给出了功能－功能行为－结构的设计模型。运动行为知识的多层表示使概念设计在多层次上产生新解,并使功能－运动行为－结构的推进过程实用化,最后给出了简单和复杂运动行为知识多层表示的示例。     

基于实例推理的夹具设计知识表示方法研究

将基于实例的推理技术应用于夹具设计过程,提出了基于夹具功能特征的实例表示方法和实例检索机制,最后,通过对基于实例推理的夹具设计过程进行的论述,证实了通过实例和方式表达夹具设计知识,可以更好地进行设计知识的转换和解释。     

基于实例推理的计算机辅助概念设计

介绍了计算机辅助概念设计和基于实例推理技术的概念。以液压缸产品为例,用Access软件和Visual C 语言开发了一个计算机辅助液压缸概念设计系统原型。     

基于知识推理的热流道系统概念设计研究

通过对设计规则的表达,提出基于知识推理与设计任务规划思路。针对热流道系统的特点,设计热流道概念设计流程;通过热流道系统的功能分解,进一步分解概念设计方案,进而建立概念设计空间模型,确定了热流道系统概念设计方案。     

基于面向对象的飞机工装概念设计知识表示

分析了目前几种常用的知识表示方法的优缺点;分析了飞机工装概念设计知识表示的特点;研究了使用面向对象技术来表示工装概念设计的知识。面向对象表示法非常适合于对产品实例以及有装配关系的零件间相互关系等知识的描述,并阐述飞机工装概念设计知识表示模型。     

面向造型设计的知识表示

针对目前人工智能技术在造型知识表达上的不足,提出了一种面向造型设计的知识表示法。以分层约束满足为基础,用多类谓词、拓扑限定、不确定性描述等方法使复杂的造型设计对象和过程得以清蜥描述。通过将复杂的空间模型以结构分解和拓扑分解的方法离散为线性域,使用空间对象的变形映射为点的丝性移动,从而使正向的造型过程和逆向的回溯过程都能沿可控路径自动进行。分析了设计知识表达的关键点,阐述了面向造型设计的知识表示法细节,结合一个分模设计的实例设计了空间推理过程,并给出了详细的结果数据。     

面向概念设计的机构知识表达与组织

知识是一些事实或事实的抽象,是对客观事物某方面属性的概括,知识是具有一定目的的信息。知识也是进行计算机辅助概念设计自动化的前提和基础,涉及机构概念设计求解的知识较多,需要对它们进行合理地表达及组织,知识表达是后续推理过程的一个基础和关键,是计算机推理求解的前提。首先对功能知识、约束行为、机构元知识进行表达,提出面向对象的机构知识表达和组织策略,然后利用关系数据库表对它们进行存储并建立它们之间的联系,最后阐述了其映射推理过程,对于进一步开发计算机辅助设计软件系统具有一定的意义和价值。     

An integrated knowledge representation model for the computer-aided conceptual design of mechanisms

An integrated knowledge representation model, namely the topology structure behaviour function (TSBF) model, is presented for the computer-aided conceptual design of mechanisms (MCACD) in this paper. The model covers both qualitative and quantitative knowledge representations of generic mechanisms. A class hierarchy consists of the abstract mechanism, the embryo mechanism, and the concrete mechanism is then proposed for object-oriented modelling. Based on the TSBF model, several reasoning techniques are integrated to achieve a relatively comprehensive environment for MCACD. The corresponding reasoning process is mainly based on a backward chaining of solutions representation and retrieval, a forward chaining of compositional behaviour reasoning with constraint propagation and satisfaction, and a forward chaining of type synthesis. Coarse optimizations for certain mechanisms are also integrated on the quantitative level. The applicability of the new model is demonstrated by the conceptual design of a zigzag mechanism.     

The establishment and reasoning of knowledge base system for mechanism kinematic schemes

As one of the key problems of computer-aided conceptual design (CACD) for mechanism kinematic schemes, the effective establishment and management of knowledge base systems of kinematic behaviours and mechanisms is still troubled by information redundancy and unreasonable structure at present. Retrieval efficiency and solving intelligence of knowledge base reasoning systems on the basis of the knowledge classification method mentioned above have many unsatisfactory factors. So in this paper, firstly, data standardization technology and combined classification methods have been applied to carry out the classification of kinematic behaviours and mechanisms in the mapping field between the kinematic behaviour level and the mechanism level of conceptual design. Also, the principle of computer coding and storing have been built to give a fast and broad selection of mechanisms that meets the requirements of basic motion characters. Then on the basis of what was mentioned above, the heuristic matching propagation principle (HMPP) of kinematic behaviours and its truth table serve as a guide to perform mechanism type selections. The knowledge base automatic reasoning system of mechanism kinematic schemes based on HMPP is developed. By means of depth first search strategy, the motion requirements are matched against objects in the knowledge base along the orientation of function unit-mechanism IDfunction unit IDkinematic behaviour ID(output/input)motion type coding/ continuity coding/linearity coding/directionality coding at four different levels of abstraction. Top-down design process in this paper conforms to the law of innovative thinking for designers. If a direct match in a higher level was not discovered, then the design course will be transformed into the match at a low level automatically. According to the truth table of HMPP, once non-zero elements in kinematic behaviour ID (1 or 2) appear in the matching process, they will propagate until the solving process is over, and become one of the coding of the feasible solutions. The heuristic nature of HMPP presents a top-down solving method to decompose the complex requirements into several simpler ones. Different from traditional solving methods, the method presented in our research work has two advantages. Firstly it is easier to be operated and realized with a computer. Secondly, it is a creative process by nature. Finally, an application is given to indicate its practicability and effectiveness.     

DWELL-EXPERT:计算机辅助间歇运动连杆机构概念设计系统

以间歇运动连杆机构的设计为例,重点讨论了基于功能、约束和结构的概念设计方法在机构概念设计中的应用,包括了设计空间的离散化、推理网络的构成及其推理方法等。本文所提出的思路和方法,对于其他机械产品的概念设计也有一定的参考价值。     

半导体制造业预警系统的知识表示研究

运用知识表示法中的语义网络表示法,作为半导体制造业预警系统中指标本体的描述方法,以Dub lin Core元数据作为知识标注;给出基于OWL Dub lin Core的形式化描述;最后用谓词逻辑和产生式表示法相结合作为知识库中预警规则的描述方法。     

产品设计的知识模型建模技术研究

针对传统CAD模型主要是几何模型的特点,提出建立基于产品几何模型的产品知识模型。详细叙述知识模型的知识表示、知识获取和知识重用方法。通过对知识的获取和重用,实现产品自顶向下的设计;运用知识模型的建模控制方法实现产品的设计控制。     

A new symbolic representation method to support conceptual design of mechatronic system

Regarding the typical mechatronic system that realizes controlled motion behaviour as the research object, the mechatronic system is composed of three subsystems, they are generalized executive mechanism subsystem, sensing and testing subsystem, and information processing and control subsystem. Based on the three subsystems, a new kind of symbolic representation method to represent a design scheme of mechatronic system is presented. This symbolic representation method includes graphical symbols, literal symbols and port information flows on the abstract layer of basic mechatronic function units in common use. Two applied instances are given. The method standardizes scheme representation of mechatronic system. The purpose is that the computer can identify and operate the standardized scheme representation. Furthermore, the method can be implemented in connection with related knowledge base to produce creative scheme. The symbolic representation method provides theoretical basis for computer aided conceptual design of mechatronic system.     

基于知识的注塑模概念设计系统研究

提出了应用“需求特征”、“功能”、“结构”概念设计三要素构建设计规则的知识表达方法,建立了注塑模概念设计知识库。模架概念设计采用数值计算方法,其它结构系统采用基于需求—功能—结构三层映射的概念设计方法,系统的设计思想符合设计方法学理论和工程实际。系统基于PDM技术实现了与注塑模设计平台其它子系统的良好集成。