面向典型宇航产品的工艺知识库研究

我国航天事业的快速发展对构建面向典型宇航产品的工艺知识库提出了迫切的需求。在对典型宇航产品工艺知识研究的基础上,针对典型宇航产品工艺知识的特点,构建了基础资源类知识、工艺方案类知识和工艺经验类知识表示模型,设计了面向典型宇航产品的工艺知识库,并通过典型宇航产品工艺知识库原型系统验证了知识库的实用性。     

工艺设计知识库的建造与维护

文中根据工艺设计知识的特点,构造了层次化的知识表达、组织与知识库模型,分析了工艺知识库不一致的表现形式,并给出了相应的一致性验证算法,提出了基于广义决策表的知识库完备性检查方法。     

基于专家系统技术的MEMS虚拟工艺库

虚拟工艺是MEMS器件计算机辅助设计中对工艺过程仿真的部分,根据版图设计、层定义和工艺文件来生成器件模型,并进行三维模型显示.本文在虚拟工艺库中引入了专家系统的技术,将已有的工艺知识分别描述成专家系统知识库中的规则,推理机部分与知识库分离,使系统有较好的可扩充性.本文给出了一个剖面图的实例,证明其可行性.     

电动工具工业设计本体知识库的构建方法研究

本文主要介绍了基于本体的工业设计知识库的构建,以电动工具为例,在研究了本体以及知识库等相关理论的基础上,将本体论引入到工业设计知识库的构建过程中,提出了构建基于本体的电动工具工业设计知识库,介绍了知识库构建方法与步骤,搭建了基于本体的电动工具工业设计知识库的基本模型。     

CAPPFramework 5.0

目前企业对CAPP的需求正由传统的计算机辅助填卡片式CAPP系统向工艺规范化、标准化、集成化及工艺设计与信息管理一体化的制造工艺信息系统这一趋势发展。CAPPFramework以企业的现实需求为基础,在国内率先提出"以交互式设计为基础、以产品数据为核心、工艺设计与管理一体化"的CAPP方法论和应用解决方案。最新推出的CAPPFramework5.0是一个"以工艺知识库/产品工艺数据库为核心,集成工艺知识库管理工具等应用支持工具以及专家系统等智能应用,并提供丰富的二次开发工具,能广泛应用于各种类型的企业以及企业不同层次、企业的不同工…     

基于遗传算法的污水处理工艺流程优化

污水处理工艺是针对城市生活污水和工业废水的处理问题所提出的一套完整的解决方案,并且被广泛应用于各个领域.城市污水处理工艺应根据处理规模、水质特性、受纳水体的环境功能及当地的实际情况和要求,在工艺技术特性与经济成本的衡量中选择优化方案确定,其可以看作是一种特殊形式的多参数优化问题:首先统计污水处理的工艺方法并设计污水处理工艺知识库;其次将各工艺的参数和环境信息作为输入,以工艺知识库作为支撑,依托设定好的智能算法自动生成由工艺知识库中的工艺组合而成的方案,方案包括各工艺模块的顺序、工艺内部组件的尺寸、预测运行成本以及处理效果.本文提出了使用messy遗传算法对污水处理工艺流程进行选优推荐,将工艺序列的总成本的倒数作为适应度,根据工艺知识库与优化目标,自动生成在多个污染物指标达标的情况下成本最低的优化方案.通过实验验证,messy遗传算法能够在工艺序列长度变化的情况下实现方案的高效准确推荐.     

钢丝绳CAD/CAPP系统设计与实现

结合钢丝绳生产的实际需要,提出将钢丝绳的 结构设计与钢丝绳的工艺设计一体化的设计方法,详细分析了钢丝绳结构设计的步骤、理论 计算方法以及在工艺设计过程中涉及的一些主要因素、设计流程．在此基础上结合具体的生 产工艺和生产计划要求,建立相应的设计知识库和并行设计结构框架,实现钢丝绳的智能设 计．     

一种计算机辅助工艺规程设计的专家系统BUAA CAPP

机械加工中的工艺规程设计对产品质量,生产率,生产周期,经济效率有着决定性的影响,CAPP(Computer Aided Process Planning),即计算机辅助工艺规程设计,既可在目前常规生产中发挥作用,也可作为CIMS系统的CAD/CAM的接口技术发挥作用。本文介绍一种CAPP的专家系统BUAACAPP,它是一个产生式系统,它的知识库由说明性知识库,规则库及策略库三大部分组成。说明性知识库存放有关零件成品的要求及零件在各加工阶段的状态的一些信息,即对事实世界的状态的描述说明,为了有利于动态知识库的形成,该知识库的知识表达方法采用了框架表示的方法。规则库按不同问题属性分別存放规则,即把对不同问题的加工处理规则分別存放于不同的规则子集中,减少搜索时间,高效率地生成功态知识库,提高解决问题速度,共有六个规则子集。BUAACAPP的推理系统是一个前向产生式系统,它把零件成品的需求当作初始态,毛胚当作目标,从零件成品的需求出发,推导出把毛胚加工成零件的工艺过程程。BUAACAPP采用了与或图搜索的方法。BUAACAPP带有一个简单的学习系统。     

行业信息化知识库系统知识库设计

行业信息化知识库(KBI)有别于一般的知识库和专家系统,所以根据需求,采用了知识本体的知识表示形式,为了更合理的建设知识库,通过对行业信息化知识的行业结构分析,构建了知识模型,并依据知识表示形式以及构建的知识模型,设计了行业信息化知识库系统的知识库.该知识库是针对战略物资行业的,提出了知识库系统的总体结构,把知识库和数据库相结合,进行了知识库结构的逐步设计.     

基于本体的机械工艺知识库构建方法

提出一种基于本体技术的机械工艺领域工艺知识库构建方法。首先对机械领域工艺知识进行了定义和分类,然后利用本体技术实现了工艺知识库定义与构建,并通过网络本体语言实现了工艺知识本体库的描述。该方法可以实现工艺知识的规范明确描述,并在一个较高的平台上提供知识重用和系统架构。     

Knowledge capturing methodology in process planning

In process planning, a proper methodology for capturing knowledge is essential for constructing a knowledge base that can be maintained and shared. A knowledge base should not merely be a set of rules, but a framework of process planning that can be controlled and customized by rules. For the construction of a knowledge base, identifying the types of knowledge elements to be included is a prerequisite. To identify the knowledge elements, this paper employs a three-phase modeling methodology consisting of three sub-models: object model, functional model and dynamic model. By making use of the three-phase modeling methodology, four knowledge elements for process planning are derived: facts (from the object model), constraints (from the functional model), and way of thinking and rules (from the dynamic model). facts correspond to the involved data objects, and constraints to the technological constraints of process planning. The way of thinking is a logical procedure for quickly decreasing the solution space, and rules are key parameters to control the way of thinking. The proposed methodology is applied to the process planning of hole making.     

A knowledge-based process planning framework for wire arc additive manufacturing

Wire arc additive manufacturing (WAAM) provides a rapid and cost-effective solution for fabricating low-to-medium complexity and medium-to-large size metal parts. In WAAM, process settings are well-recognized as fundamental factors that determine the performance of the fabricated parts such as geometry accuracy and microstructure. However, decision-making on process variables for WAAM still heavily relies on knowledge from domain experts. For achieving reliable and automated production, process planning systems that can capture, store, and reuse knowledge are needed. This study proposes a process planning framework by integrating a WAAM knowledge base together with our in-house developed computer-aided tools. The knowledge base is construed with a data-knowledge-service structure to incorporate various data and knowledge including metamodels and planning rules. Process configurations are generated from the knowledge base and then used as inputs to computer-aided tools. Moreover, the process planning system also supports the early-stage design of products in the context of design for additive manufacturing. The proposed framework is demonstrated in a digital workflow of fabricating industrial-grade components with overhang features.     

A knowledge-based inspection process planning system for coordinate measuring machines

The coordinate measuring machine (CMM) is one of the most effective geometry inspection facilities used in manufacturing industry. To fully utilize its capabilities in a computer-integrated manufacturing (CIM) environment, we should integrate CMM with other systems and facilities. This paper presents the development of a knowledge-based inspection planner based on the fundamental principles of AI planning to integrate computer-aided design systems and CMMs. The issues involved in CAD-directed inspection process planning are examined; the task of inspection process planning is decomposed into a number of sub-tasks. According to the task decomposition, a knowledge-based planning system was designed with several modules. Each of these modules consists of a knowledge base, a control operator, a context and a communication interface. The knowledge base is the local knowledge source for problem solving; the control operator determines when and where the knowledge is applied; the context contains the initial planning state which is essential input part information, the intermediate planning states which result from the tentative decision made by the modules, and the goal state. The module interfacing was realized by directly calling procedures defined in other modules to pass the planning tasks and decisions. Examples are included to explain the planning knowledge and strategy.     

基于本体的智能规划方法研究及应用

针对经典智能规划方法在利用领域知识方面存在的不足,将先进的知识工程方法与通用智能规划算法相结合,提出了一种新型的基于本体的智能规划技术,它能够综合利用本体知识库中的领域知识对特定领域问题进行合理高效的规划求解,同时给出了一套构建用于支持这类规划过程的领域知识本体库的实用方法。实验结果表明,该方法能够有效地解决复杂的实际应用问题,使由此建立的规划系统真正达到实用水平。     

面向手机3D动画自动生成的空间分层布局规划

手机3D动画自动生成系统是将用户发送的短信,经过信息抽取、情节规划等一系列的处理,最终生成一段与短信内容相关的三维动画并发送给接收方这一过程.布局规划是系统的一个重要组成部分,其功能是将模型放置到场景的可用空间上.通过对布局问题的研究,本文提出了一种基于区域布局和模型布局的分层布局方法,其包括定性规划和定量计算两个部分,利用语义网技术建立分层布局知识库,基于规则的方法推导出分层布局定性规划方案,并对模型位置进行动态计算.最后,通过实验验证了分层布局规划的有效性和多样性,满足了自动生成系统对布局规划的要求.     

A privacy-preserving model for multi-agent propositional planning

Abstract

Over the last years, the planning community has formalised several models and approaches to multi-agent (MA) propositional planning. One of the main motivations in MA planning is that some or all agents have private knowledge that cannot be communicated to other agents during the planning process and the plan execution. We argue that the existing models of the multi-agent planning task do not maintain the agents’ privacy when a (strict) subset of the involved agents share confidential knowledge, or when the identity/existence of at least one agent is confidential. In this paper, first we propose a model of the MA-planning tasks that preserves the privacy of the involved agents when this happens. Then we investigate an algorithm based on best first search for our model that uses some new heuristics providing a trade-off between accuracy and agents’ privacy. Finally, an experimental study compares the effectiveness of using the proposed heuristics.     

Integrating multi-granularity model and similarity measurement for transforming process data into different granularity knowledge

The core of intelligent manufacturing is to incorporate the expert knowledge in manufacturing process, and knowledge transformation is the key to knowledge accumulation and application. In this paper, the research carried on transformation for different granularity knowledge from the cases of sheet metal parts in process planning. First of all, this paper analyzes the difference of organization structure between process data and knowledge in the base. The multi-granularity model of process knowledge is established in the form of tuple, which helps to clarify the hierarchy structure and internal relations. Thereafter, the concrete process is presented to transform single granularity process data into multi-granularity process knowledge, i.e., process data extraction, state determination and knowledge construction. With respect to state determination, similarity measure methods for different granularity knowledge are established to reduce the redundancy in the transformation process. As a novel approach, sequence alignment based on edit distance is proposed to calculate similarity exactly between two process flows. Finally, the knowledge transformation tool for different granularity knowledge is developed to enhance knowledge acquisition and improve the strength of knowledge reuse in fabrication order design for sheet metal parts through application of the above method. Also an example is given to illustrate the usefulness of the proposed method.     

Data and knowledge modeling for design–process planning integration of sheet metal components

Realizing design–process planning integration is vital to the competitiveness of manufacturing organization and its ability to respond rapidly to market changes. Many attempts have been made in the past proposing the integration of the two activities based on product data models. However, both design and process planning activities are knowledge intensive. An effective integration is possible only if both data and knowledge models form a basis for integration. This paper presents key issues related to data and knowledge modeling for integration of design (CAD) and process planning (CAPP) activities for sheet metal components. Previous attempts to model data and knowledge have concentrated only on either design or process planning and not from an integration point of view. Moreover, in these attempts data and knowledge models have been proposed without attempting to relate the two. The same has been overcome in the present work. An integration framework based on data and knowledge is proposed at the end and discussed for domain of design–process planning integration of sheet metal components.     

Systematic modeling and reusing of process knowledge for rapid process configuration

Rapid product development relies heavily on quick and reliable process planning and knowledge reuse. Process configuration borrows the principles of product configuration and applies them to process planning. It allows the reuse of hierarchical, historical and case-based manufacturing process knowledge to generate process plans efficiently and effectively. This paper presents a systematic knowledge model for manufacturing process cases. The model represents process knowledge at different levels of granularity and to facilitate process configuration. With this knowledge model the process knowledge is categorized into 6 levels: (i) core process skeletons, (ii) process networks, (iii) process routes, (iv) process segments, (v) processes/workplan, and (vi) operations/working step. Based on the systematic knowledge model, this paper also proposes an approach to achieve rapid process configuration by reusing the process knowledge and by performing the involved configuration rules so as to create an appropriate, reliable and effective process plan. The prototype for a graphical process planner based on this knowledge model is developed and an aerospace example is used to validate the proposed process knowledge model and process configuration.