Representation and similarity assessment in case-based process planning and die design for manufacturing automotive panels

This work improves process planning and die design in automotive panel manufacturing using a novel case-based reasoning (CBR) methodology. An innovative indexing representation and retrieval approach are also addressed. The flat-bend graph, which is utilized to represent a panel model with a B-rep structure, retains geometric and topological data in the Standard for the Exchange of Product model data format. Flat-type faces collected into several groups are represented by graph nodes, and bend-type faces are represented by graph arcs. Based on the topological information between bend-type faces and flat-type faces, a graph is constructed. Additionally, the holes detected are considered another graph node types. Geometric information and stamping parameters are utilized as graph attributes. To retrieve an appropriate case for a potentially huge search space, independent maximal cliques detection is applied. All independent maximal cliques that represent the maximum number of features shared by models are identified. Based on the retrieval result, previous process plans and die sets can be acquired for use by new cases. Experimental results obtained using the CBR system integrated with the product data management system demonstrate the practicality of reusing previous designs to accelerate stamping process planning and die design.     

基于实例推理的产品概念设计系统

产品概念设计是设计过程中最具有创造性的阶段。本文分析了产品概念设计过程的主要研究内容，提出了基于实例推理的产品概念设计模型结构，采用面向对象方法进行实例的表示，通过基于实例的推理技术获得相似实例。开发了一个基于实例推理的产品概念设计原型系统。     

基于SolidWorks的减速器产品三维参数化变型设计

以Solidworks软件为开发平台,采用基于实例的推理方法和用面向对象的模块化设计思想建立减速器参数化变型设计系统,围绕基于Solidworks的减速器参数化变型设计系统的关键技术、实例推理技术的变型设计原理和一般步骤,在Solidworks平台上的具体实施进行了探讨,并以齿轮轴零件为例具体说明参数化变型设计的全过程.     

基于案例推理的大件运输安全管理系统研究

基于案例推理方法是一种基于经验知识推理的求解方法,适用于经验丰富的领域.针对公路大件运输过程中积累的大量运输经验,将基于案例推理方法应用于大件运输安全管理中,研究设计了基于案例推理的大件运输安全管理系统,以保障大件运输的安全性和可靠性.在分析系统体系结构、特点的基础上,建立大件运输案例知识表达模型,设计基于案例相似度的检索规则和方案修正策略,采用VB开发工具进行开发,实现系统各功能.通过在大件运输企业的实际运用,验证了该系统的科学性与有效性.     

A Case-Based Computer-Aided Process-Planning System for Machining Prismatic Components

This article deals with a process-planning system that uses case-based reasoning methodology. Briefly, case-based reasoning is an intelligent problem-solving technique which works by searching through a database for previously solved problems for one or more cases whose identifying features closely resemble the current problem. The case-based reasoning system used in this article to develop a process plan, typically consists of three modules, i.e. the part input and representation module, the case retrieval, and case adoption module. In this paper, new approaches have been proposed in all three modules. By incorporating a multiparametric and absolute-matching technique, the case retrieval module especially has become more powerful. A practical approach has been suggested in this research to compute the similarity between part input and case. An illustrative example is included to demonstrate the proposed system.     

基于实例的汽车覆盖件模具结构智能CAD

覆盖件模具的设计和制造是开发汽车新车型的“瓶颈”环节。鉴于覆盖件模具结构的特点,其设计质量完全取决于设计人员的经验和水平,难以保证。本文阐述了汽车覆盖件模具结构设计采用智能CAD的原因和意义,分析了基于实例设计（CBD）方法优势,指出CBD方法是最常用、也是最为成功的用于模具结构设计的智能CAD方法,论文提出了“实例＝实例模型＋实例数据”的描述方法,在正确处理设计尺寸参数化程度的基础上,通过建立面向装配的实例模型和推理机制,成功地进行了基于实例的覆盖件模具结构智能设计。     

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。     

基于实例推理的自动武器辅助设计系统

介绍了基于实例推理与设计的原理,提出了一种支持自动武器设计的计算机辅助设计系统.详细探讨了系统设计方案生成过程中的各个关键技术环节:用XML进行实例的知识表达,用比较归纳法与最近相邻法相结合的方法进行实例检索.在此基础上,建立了一个基于实例推理的自动武器辅助设计开发管理平台.     

基于实例推理的高速切削数据库系统

由于目前十分缺乏合理适用的高速切削数据 ,使建立高速切削数据库遇到了很大困难 ,也在一定程度上限制了高速切削技术的推广应用。利用基于实例推理技术 ,可为建立高速切削数据库提供一个可行且有效的方法 ,即将以前切削加工积累的切削数据和经验存储在数据库中 ,为新的工件加工问题提供参考解决方案。建立了简洁可行的用结构化数据表示的实例描述模型 ,分析了实例相似度的计算问题并介绍了实例检索的具体方法。     

基于知识的模具设计

模具设计是一个与工程知识、设计经验密切相关的过程。基于知识的模具设计,结合事例推理和专家系统两种重要的知识处理技术,极大限度的利用已有的知识和以往设计经验对新模具进行设计,它是模具设计智能化、快速化的重要技术手段。     

工艺设计中支持事例推理的扩展对象模型

建立一个基于事例推理的CAPP系统的事例表达模型。对传统的对象模型进行了扩展，并在此基础上给出了支持事例推理的事例表达模型，该模型具有表达零件工艺知识和复杂事例的能力，以及支持在事例推理全过程中对信息的需求，为相似零件检索和零件事例的自动修改打下了基础。     

A study of advanced die-casting technology integrating CAD/RP/FEA for Zn castings

By means of computer aided engineering (CAE) is developed an integrate CAD/RP/FEA system to assist reducing the lead-time of die-castings design and upgrade the die-casting manufacturing technology parameters for zinc castings. The rapid die-casting methodology developed integrates: conceptual design; virtual prototyping (VP), rapid prototyping (RP), P-Q² technique, finite element analysis (FEA) to improve die-casting process and numerical control (NC) to upgrade die-casting manufacturing parameters. Thermal fluid flow and heat transfer modelling are performed to simulate die-casting manufacture technology to predict defects, increase yield and to improve the manufacturing process. An improved die-casting manufacturing process supported via CAD/RP/FEA technologies and NC control are demonstrated through a die-casting case study to manufacture sound zinc die-castings and conclusions are presented.     

基于贝叶斯推理的浇注系统选型方法研究

针对压铸模浇注系统设计过程中存在大量不精确数据的情况,提出基于贝叶斯推理算法的压铸模浇口类型选择方法.结合浇注系统的类型划分,建立相应的类型标准模型以及典型属性模糊向量,并采用模糊数学的方法处理设计信息中不精确约束值,最后将贝叶斯理论应用于推理过程中.该方法将概率逻辑与模糊数据处理的思想结合在一起,将贝叶斯推理方法应用于基于智能化设计的浇注排溢系统中,提高了对设计信息的获取能力以及产品设计的智能化程度.     

CBD在轴类零件设计中的应用研究

在产品设计中,大部分零件设计是在已有零件的基础上进行的变型设计,因此如何更好的重用已有的经验和知识将直接影响到新产品开发的速度和质量.将基于案例设计(CBD)技术引入到轴类零件的变型设计中,研究了轴类零件设计过程中案例的表示、案例的检索以及案例的重用和修改等操作,并开发了相应的CBD软件系统验证了本文研究的结果,实现了轴类零件的基于案例设计.     

Method for improvement of die-casting die: combination use of CAE and biomimetic laser process

Die service life improvement is an important problem in high-pressure die-casting industry. Die service life, which is defined as the maximum product number produced before it fails, and die performance directly determine the production cost and quality of die-casting product. To reduce the repair and maintenance costs, an approach to prevent die from thermal damage and prolong the die lifetime is required. Biomimetic laser-remelting process (BLRP) provides a promising method to improve the service life of die-casting mold. However, the laser processing regions can only be determined by experiences. In order to determine the exact laser processing regions for a set of new die before BLRP, a combination system of CAE and BLRP is proposed in this paper. Through analyzing the mold filling process and the temperature distribution, potential thermal cracks are worked out by numerical simulation system, which are the laser processing regions. The method proposed in this paper advances the efficiency of the BLRP. And practical production validates the veracity and the reliability of the method.     

The runner optimisation design of a die-casting die and the part produced

The accurate prediction of die-casting performance is essential for the design of die-casting dies. The main purpose of die design is to produce an accurate part, but a key role in a good design is also the design of the runner. In order to understand the practical conditions in die casting, this paper studies the runner part and die body parts which have been considered separately during the experiment. A die-casting test has been designed according to experimental methods and the runners have a total of 23 sets of tests.A finite-element method was used to obtain the displacement from the measurement of the temperature in the cavity, and an abductive network has been built for modelling the diecasting process. The abductive network is composed of a number of functional nodes. Once the die-casting parameters (high-speed injected position, runner injected angle, runner sectional ratio) are given, the die-casting performance (the displacement) can be accurately predicted by this network. The optimal die-casting parameters can be searched for by a simulation annealing optimisation algorithm using a performance index to obtain a perfect part.     

基于混合推理的高速切削数据库系统的建立

高速切削包含大量相互作用的参量,详细地讨论了这些参量之间的相互关系和作用,并对工程中常用的智能方法进行了分析比较。在此基础上,提出了基于规则和实例混和推理建立高速切削数据库系统。在该系统中,实例推理起主要作用,当实例库中没有积累相关数据时,采用规则推理求解。根据各属性的特点和高速切削加工知识,确定了实例属性局部相似度的计算方法和各属性整体相似度的权值。为了快速查找实例,采用全部属性值索引和单个属性值索引两种索引方式,并采用规则推理来补充和验证实例推理的结果。规则和实例混合推理的采用,使系统的数据采集和知识更新简单易行。     

基于粒子群优化案例推理的RH终点温度预测

针对RH流程终点钢温预报问题,提出了一种基于多元线性回归和粒子群优化算法改良的案例推理方法。首先,对待一般案例推理方法中缺乏影响因素的问题,利用多元线性回归的方法进行属性约简;其次,面对案例检索中相似度计算缺乏权重计算方法的问题,采用粒子群优化算法对权值进行优化;最后,基于简化的影响因素和优化权重,采用改进的灰色关联相似性的案例检索来预测RH终点的钢水温度。利用某钢铁厂RH工艺的实际生产数据,分别对多元线性回归、BP神经网络、一般案例推理方法和粒子群优化案例推理方法进行测试,从结果可以看出,文中所使用的基于粒子群优化过的案例推理方法的预报精度,相较于多元线性回归,BP神经网络以及一般案例推理更加准确。     

一种高效的充氧压铸模排气系统设计方案

充氧压铸法能有效的避免在压铸件中产生气孔等缺陷,在生产中的应用已日益广泛。在对现有模具的结构方案进行分析的基础上,设计了一种高效实用的充氧压铸模排气系统结构方案。新的设计方案改变排气的沿程阻力,不改变原有的型腔结构,达到快速置换氧气的目的,来实现效率的提高;另一方面,改变了排气通道,扩大了排气的通道,减缓了排气的速度,减弱了氧气传感器的冲击力量,降低了对氧气传感器的损坏。     

基于实例推理的自动化产品辅助设计研究

介绍了基于实例推理的特点和实现方法 ;研究了在基于实例推理的自动化产品设计中实例的表达、实例的索引和检索等关键技术 ;提出了适合自动化产品设计的实例表达方式和检索方式