EFDEX: A Knowledge-Based Expert System for Functional Design of Engineering Systems

This paper presents a knowledge-based system, ‘EFDEX’, the Engineering Functional Design Expert, which was developed using an expert system shell, CLIPS 6.1, to perform intelligent functional design of engineering systems. On the basis of a flexible, causal and hierarchical functional modeling framework, we propose a knowledge-based functional reasoning methodology. By using this intelligent functional reasoning strategy, physical behavior can be reasoned out from a desired function or desired behavior, and inter-connection of these behaviors is possible when there is compatibility between the functional output of one and the corresponding functional requirement (e.g. driving input) of the next one. In addition, a complicated, desired function which cannot be matched with the functional output of any behavior after searching the object-oriented behavior base, will be automatically decomposed into less complex sub-functions by means of relevant function decomposition rules. An intelligent system for the functional design of an automatic assembly system provides an application of this intelligent design environment, and a demonstration of its methodology. In this paper, a knowledge-based functional representation scheme which integrates two popular AI representation techniques (object-oriented representation and rule-based representation) is also proposed as a prelude to a knowledge-based functional design system     

IKOOPPS: an intelligent knowledge-based object-oriented process planning system for the manufacture of progressive dies

Abstract: This article describes an intelligent knowledge-based object-oriented process planning (IKOOPP) system for the manufacture of progressive die plates. A die assembly is designed using a variety of standardised components based on a computer-aided design (CAD) system. A feature recognition module extracts all the pertinent geometrical properties and functional attributes of each machining feature from the CAD representation models. These properties and attributes are converted into an object-oriented representation. Knowledge of the functions of the machining feature allows process planning information to be automatically deduced. Specialised tool engineering knowledge are formulated as production rules or procedures to establish the required set of cutting tools, together with the machining allowances and sequence of operations.     

基于混合功能推理的机械系统概念设计的研究

给出了产品设计说明形式化的描述,应用P/T网对原型机构抽象结构进行表示,利用编码技术对功能要求、功能约束及结构约束进行编码,建立了原型机构知识库。在所提出的基于设计说明和问题解重定义的正、反向混合推理方法的基础上,采用功能相似性度量的控制策略,进行复杂机械系统的概念设计,完成整个概念空间的构建。最后用实例对推理过程的自动性及方法的有效性进行了验证。     

基于实例的产品设计知识获取方法及实现

现代产品设计是面向市场、功能驱动以及基于新知识的设计，而知识获取是关键步骤。采用设计实例的形式对已有设计进行封装和组织，通过产品设计实例面向对象表达模型，将设计需求（包括性能需求、环境约束和成本约束）、设计任务、设计过程和设计方案封装在一个设计实例中，体现了功能驱动、面向市场的现代设计特征。在此基础上，利用Sybase公司的PowerDesigner8.0建模工具，进一步提出产品设计实例的获取模型，并对实例获取的关键技术进行了讨论。以滑动轴承设计为工程应用背景，选择应用于涡轮机的四油叶径向滑动轴承为设计实例，详细描述了集成于SolidWorks2000的滑动轴承设计实例获取模块的应用过程，验证了上述模型的正确性和可行性。通过对设计实例进行表达、获取和存储，为后续的基于实例推理的产品设计方法打下基础，同时以对外提供功能的形式对并行设计环境下的功能检索提供支持，推动现代产品概念设计自动化进程。     

CAD系统设计中的形式化方法与功能命题

本文结合作者多年的研究实践，对CAD系统功能设计理论和方法进行研究，并在此基础上提出和建立CAD系统功能设计的数学模型，其中包括：(1)介绍需求分析的形式化描述和表示方法，建立需求空间结构；(2)提出复合功能、设计逻辑、功能与参数依赖及交互效率等新概念，并分别建构复合功能的构造和效率命题；(3)阐述这些理论和方法在自行开发的专业化系统中的应用。     

Knowledge-based approach and system for assembly-oriented design,Part II: the system implementation

Assembly is one of the most important stages for product development. Assembly-oriented design (AOD) is a new approach to designing assemblies, which uses a number of design and analysis tools to help the designer plan out and analyze candidate assembly schemes prior to having detailed knowledge of the geometry of the parts. Using this approach, many assembly schemes can be inexpensively evaluated for their ability to deliver the important characteristics of the final product. This research proposes a knowledge-based approach and develops an expert design system to support top-down design for assembled products. The presentation of research report is divided into two parts: the knowledge-based approach (Part I) and the knowledge-based expert design system (Part II). This paper is the second part of the report (Part II). It will focus on the development of knowledge-based expert design system for assembly oriented design. The knowledge-based assembly oriented design system, i.e., the assembly oriented design expert system (AODES) is constructed to integrate assembly modeling and design, assembly planning, assemblability analysis and evaluation within a concurrent engineering environment. This intelligent system is implemented by integrating object-oriented representation, constraint-based modeling, rule-based reasoning, truth maintenance, and interfacing to database management system and CAD module, in which fuzzy logic based knowledge representation and inference technique are also applied to deal with uncertain data and knowledge in the design process. The developed system differs from the existing systems adopting part-first bottom-up modeling technique, in which a comprehensive intelligent framework is used for assembly modeling and design in a top-down manner from the conceptual level to the detailed level. It is able to help obtain better design ideas, provide users with suggestions so as to create and improve a design, and therefore give users the possibility to assess and reduce the total production cost at an early stage during the design process. Through the use of the system, the concurrent engineering knowledge can be effectively incorporated into the assembly design process in an integrated manner. A case assembly design shows that the intelligent modeling and design system is feasible.     

机械产品概念设计中的知识表示

研究了计算机辅助概念设计中的关键技术——知识表示．将行为域引入公理化设计作为功能域和载体域之间的转换桥梁，针对该域结构定义扩展“之”字映射，建立了不同层次功能、行为和载体之间的映射关系；构造了概念设计方案的知识表示模型——域结构模板；针对一类产品的知识表示模型——概念空间，给出了基于概念空间的概念设计方案生成过程．最后以工业平缝机为例对所述模型和方法加以说明。     

利用用户定义特征实现基于约束设计

提出了基于约束的用户定义特征（User Defined Feature,UDF)定义与比实例化的通用机制及基于约束的特征库管理,并应用于国产CAD／CAM软件金银花（Lonicera)系统,以航空发动机转子为例,建立了转子特征库,对系统功能进行了验证。该项工作既为详细设计阶段考虑装约束和制造约束提供了方便,提高了设计效率,也为将用户定义特征与产品功能相联系、以支持计算机辅助概念设计打下了基础。     

Developing a quantitative intelligent system for implementing concurrent engineering design

This research focuses on the development of a quantitative intelligent system for implementing concurrent engineering design. The paper first discusses the task of concurrent engineering design and the basic requirements for conducting integrated concurrent engineering design. The proposed quantitative intelligent system approach combines qualitative reasoning, based upon design and manufacturing knowledge, and quantitative evaluation and optimization, conducted using design information and manufacturing data generated in the knowledge-based reasoning. The method allows considerations on non-operating principle aspects of a product to be incorporated into the design phase, such as manufacturing, maintenance, service, recycle, etc., with an emphasis on production costs. The proposed method serves as a convenient software tool for gathering information required in the concurrent engineering design process and integrates tasks from different parts of the product development life cycle, particularly function design, manufacturability analysis and production cost estimation. A prototype software system is developed based upon this method using Smalltalk-80. In the prototype system, concurrent engineering design is carried out by: (1) describing and representing design requirements; (2) generating feasible design candidates and evaluating their design functions; (3) representing design geometry; (4) finding the associated production processes and predicting the production costs of each feasible design; and (5) identifying the costeffective design that satisfies given design requirements and requires minimum production costs.     

实体造型中的几何约束

实体造型是一个基于约束的过程，完成从功能约束到几何约束、再到代数约束的转化而得到实体模型。本文讨论了几何约束的层次性及其表示，并且对几何约束同设计意图的关系进行了研究，提出了基于ＣＳＧ／ＧＣＧ／Ｂ－ｒｅｐ的模型表示。     

温室智能控制器硬件设计

针对温室智能控制系统功能需求.结合现场实际情况,借鉴已有研究成果,设计温室监控系统三级结构.根据系统技术指标选择传感器、控制器、采集器、通信模块,设计硬件电路和抗干扰措施.实现温室监控系统硬件架构.经过运行检验,系统达到设计功能、效果良好.     

An integrated case-based reasoning approach for intelligent help desk fault management

As modern business functions become more complex and knowledge-intensive, with increasing demands for quality services, there is an emerging trend for organisations to develop and deploy intelligent knowledge-based systems for mission-critical operations. Some of the challenges in successfully implementing this breed of systems depend on how well the intelligent system is integrated with conventional existing information systems and workflow, and the quality of the intelligent system itself. Developing quality expert systems lies in the effective modelling of cognitive processes of human experts and representation of various forms of related knowledge in a domain. An integrated intelligent system called the Intelligent Help Desk Facilitator (IHDF), has been developed for computer and network fault management. The system, which comprises various modules including an expert system, is successfully deployed in a problem response help desk environment of a local bank. This paper describes a cognitive-driven approach to the development of the expert system based on a hybrid knowledge representation and reasoning strategy. The approach incorporates a hybrid case-based reasoning (CBR) framework of techniques which include case memory organisation structures (discrimination networks and shared-featured networks), case indexing and retrieval schemes (fuzzy character-matching, nearest-neighbour similarity matching and knowledge-guided indexing); and an interactive and incremental style of reasoning. The paper discusses the design and implementation of the expert system component of IHDF and illustrates the appropriateness of the hybrid architecture for problem resolution and diagnostic types of applications.     

Theoretical foundations of planning and navigation for autonomous robots

In this article, theoretical foundations of planning and navigation systems and processes are outlined in a form applicable for autonomous robotics. the core of the theory is based upon methods developed in the team theory of decentralized stochastic control. A class of autonomous control systems is defined, and a problem of information representation is addressed for this class. A phenomenon of nesting is determined to be a key element for arranging design and control procedures for systems of intelligent control. A concept of hierarchical nested knowledge-based controller is employed in this article which enables optimum control using nested dynamic programming. an application of this concept is unfolded for a system of knowledge-based control of an autonomous mobile robot.     

KBSDT:一个知识系统开发工具

在详细分析了国际上流行的２０多个知识系统开发工具的基础上,讨论了如何设计一个知识系统开发工具—ＫＢＳＤＴ,讨论了其设计方法和准则,讲了ＫＢＳＤＴ的总体设计与实现。除此还计划将反推理机部分的工作深入,利用自然语言理解的成果开发一个高级智能接口。     

机构方案概念设计的功能向量编码方法

针对机构方案概念设计的自动化程度不高的缺陷,提出了功能向量编码方法.该方法将机构功能用功能向量表示,功能向量所包含的对偶功能向量和功能矩阵分别表示功能向量的方向特性和量化特性,同时引入了补偿矩阵以对功能矩阵进行多次分解.建立了机构功能库,开发了机构方案概念设计系统,并将功能向量编码方法应用于机构功能的提取和操作.应用结果表明,将该方法应用于机构方案概念设计是可行的,提高了机构方案概念设计的自动化程度.     

桥梁协同设计系统的数据预定义存储

桥梁协同设计过程是一个数据不断生成和处理的过程,如何提高资料存储和管理的效率是影响设计质量和设计周期的重要内容。通过对现有桥梁设计系统在数据存储方面的不足进行分析,提出协同设计环境下桥梁设计系统的数据表达模型,以此为基础研究桥梁协同设计系统的交互式预定义和基于知识的预定义两种数据预定义存储方式,通过实例对数据预定义模型的可行性进行了验证。     

A functional approach to redesign

This paper describes a methodology to assist in the identification of possible conceptual design variants during redesign. The approach is based on functional reasoning and involves: (1) the structural and functional analysis of an existing design; (2) the production of abstract representations of functions and design entities using conceptual graphs; and (3) design interrogation based on a functional tree approach. The research reported in this paper also focuses on the definition and the representation of elementary mechanical functions. Extended Backus-Naur Form (EBNF) notations are used to structure in a computable form, the relevant information (or design knowledge) conceptualised in either the conceptual graphs or the functional trees. EBNF syntax is also used to formulate rules which aid the partial automation of the reasoning process. The EBNF notations can be mapped to any programming language. A diaphragm valve is used as a case study to demonstrate the approach.     

基于活动约束系统的变量化设计

在变量化设计过程中设计对象可以看作是一个几何约束系统,这个系统由几何元素以及作用于几何元素之间的各种约束关系构成。一个复杂的设计对象所对应的几何约束系统往往包含大量几何元素和约束关系,如果不加区别地把所有的几何元素和约束关系纳入变量化求解的范围,则很难满足交互设计的需要。而另一方面几何约束系统又往往是稀疏系统：（1）作用于任一几何元素的约束很少;（2）与任一约束相关的几何元素很少。基于这一事实给出了一种预处理策略从原始几何约束系统中搜索得到一个规模较小的活动约束系统,变量化求解在活动约束系统上进行。该方法已在自行研制的参数化造型系统GEMS5．0中实现。     

具有全序时态类型集时态函数依赖集的研究

好的数据库逻辑设计目标是消除数据冗余以及插入、删除和更新异常.对于时态数据库,可以通过具有多时间粒度的时态函数依赖(TFDs)约束对时态数模式进行规范化.但是由于时间维的引入和多时间粒度的使用而给数据库设计带来巨大的复杂性.一般来说,系统所能处理的和相当多的应用所涉及到的时态类型集满足全序关系,并且具有全序时态类型集的TFD集的推导规则与传统函数依赖(FDs)的Armstrong公理有着紧密的联系.通过分析TFDs与FDs之间存在的联系,利用传统FD集的相应算法,提出了成员籍、有限属性闭包等TFD集的一些重要算法.这些算法是时态数据库进一步规范化的基础.     

Intelligent process-control system design

The use of expert systems has vast potential in an intelligent process-control system. In this paper, the issue of process-control system design using a knowledge-based approach is discussed. Expert-system techniques have been used for the design of controllers for process-control systems. The expert system is developed in conjunction with the successful application of a systematic design approach. Design knowledge has been represented using rules, facts and frames. The design process consists of a sequence of operations obtained by heuristics and experience in the design techniques.