Conceptual Design of Fixtures using Genetic Algorithms

Fixture design is a complex and intuitive process, which demands rich experience from the designer. Multiple acceptable designs are possible for a given workpiece and hence the solution space is large. Recent advances in CAD/CAM, especially in artificial intelligence, have alleviated this problem by intelligently restricting the search space considered, thus opening the possibility of obtaining better designs. Researchers have used various techniques under the general rubric of artificial intelligence to solve the fixture design problem. The most common of these have been case-based reasoning and expert systems. However, these two common methods do not ensure that the resulting solution is efficient or optimal. In this paper we propose to combine complementarily the strengths of genetic algorithms and neural networks to develop a fixture design system. Results obtained using this combined multi-agent approach for the design of fixtures are promising.     

基于DFFD的概念设计研究

概念设计在新产品开发中是十分重要的设计活动,不合适的概念设计将导致产品重新设计,延缓产品的发布。本文首先从心理学的角度对用户的概念需求加以描述,定义了概念演化过程的抽象、描述、演化、原型4个阶段,并建立了演化过程模型。接着将DFFD(DirectManipulationofFreeFormDeformation)的造型设计方法与概念设计演化相结合,将用户头脑中的抽象概念原型的描述,如概念名称、定义、属性等,直接映射为产品原型的描述,如模型约束、载荷等参数,借助DFFD的设计方法,帮助用户高效、可视化、互交的进行概念设计。最后用一个酒杯概念设计的例子介绍此方法的实际应用。     

A Prototype Knowledge-Based System for Conceptual Synthesis of the Design Process

This paper presents a knowledge-based system "KBCS", the "Knowledge-based conceptual synthesiser" that supports the synthetic phase of conceptual design. It was developed using an expert system shell called CLIPS. By using this knowledge, physical behaviour can be derived from a desired function or desired behaviour, and a functional model which represents causal relationships among the functions and behaviours can be created. In addition, complicated desired functions which cannot be matched with the functional output of any behaviour after searching the object-oriented behaviour base, will be automatically decomposed into subfunctions by means of relevant function decomposition rules. A case study for the conceptual synthesis of an automatic assembly system provides an application of this intelligent design environment, and a demonstration of its methodology. In this paper we also describe how two popular AI representation techniques, object-oriented representation and production rule representation, can be usefully integrated to solve the problem.     

支持概念设计的分布式协同设计环境的研究

一个复杂产品的概念设计往往需要多学科领域专家之间的协同。基于黑板模型 ,本文提出了一个分布式模块化协同设计框架结构。首先分别介绍了支持该框架结构的几个关键技术 ,即产品信息共享模型、设计问题的分布式构模方法以及基于约束的冲突检测方法。然后利用这些框架支持技术以及网络使能技术开发了一个分布式模块化协同设计环境 DCMDE,能有效地支持不同地理位置、不同学科的设计人员进行机械产品的协同概念设计。一个齿轮箱协同方案设计实例显示了系统的有效性     

计算机辅助概念设计研究

概念设计是整个产品开发周期中最重要的环节之一,它将决定产品的基本特征和主要框架。但由于在概念设计阶段主要的工作表现为对功能进行表示、维护和推理,而设计对象的几何信息却是不完全的,因此以几何信息为核心的传统ＣＡＤ系统对概念设计过程不能进行有效支持。针对这个问题,本文研究了ＣＡＤ系统支持概念设计过程的一些关键技术,包括功能建模和推理技术,以及计算机支持的概念设计过程和后续设计过程的集成技术。     

方案设计中的图形构思法

提出了在工程设计中进行方案设计时采用的一种辅助方法——图形构思法。这种方法层次分明 ,结构清晰 ,可以作为设计人员进行方案设计时的一个工具。     

Approximate Estimation of the Product Life Cycle Cost Using Artificial Neural Networks in Conceptual Design

In order to improve the design of products and reduce design changes, cost, and time to market, life cycle engineering has emerged as an effective approach to address these issues in today’s competitive global market. As over 70% of the total life cycle cost of a product is committed at the early design stage, designers can substantially reduce the life cycle cost of products by giving due consideration to the life cycle implications of their design decisions. During the early design stages there may be competing requirements. In addition, detailed information is scarce and decisions must be made quickly. Thus, both the overhead in developing parametric life cycle cost (LCC) models for a wide range of concepts or requirements, and the lack of detailed information make the application of traditional LCC models impractical. A different approach is required because a traditional LCC method should be incorporated in the very early design stages. This paper explores an approximate method for providing the preliminary life cycle cost. Learning algorithms trained to use the known characteristics of existing products can perhaps allow the life cycle cost of new products to be approximated quickly during the conceptual design phase without the overhead of defining new LCC models. Artificial neural networks are trained to generalise product attributes and life cycle cost data from pre-existing LCC studies. Then, the product designers query the trained artificial model with new high-level product attribute data to obtain an LCC for a new product concept quickly. Foundations for the learning LCC approach are established, and then an application is provided. This paper has been developed to provide designers with LCC information to guide them in conceptual design.     

概念设计的功能方法树

在介绍功能方法树基本原理、组成及两种扩展方法的基础上,提出功能方法树可采用自顶向下的方法建立,并提出了建立功能的方法的手工方法与用于软件编程的算法,实例表明其手工方法在产生多个设计方案的时间简实用。     

面向概念设计的产品信息建模

概念设计的主要任务是设计概念的产生和选择 ,它包含了设计中的大部分创造工作 ,是产品开发过程中最重要的环节之一。由于缺乏有效的产品信息表示方法 ,传统 CAD系统并不能对概念设计过程进行有效支持 ,然而对概念设计的计算机支持是 CAD系统发展的方向。本文在概念设计过程模型和面向对象思想的基础上 ,提出了一种面向概念设计的产品信息模型 ,为计算机辅助概念设计开辟了一条途径     

面向概念设计的产品信息建模

概念设计的主要任务是设计概念的产生和选择 ,它包含了设计中的大部分创造工作 ,是产品开发过程中最重要的环节之一。由于缺乏有效的产品信息表示方法 ,传统 CAD系统并不能对概念设计过程进行有效支持 ,然而对概念设计的计算机支持是 CAD系统发展的方向。本文在概念设计过程模型和面向对象思想的基础上 ,提出了一种面向概念设计的产品信息模型 ,为计算机辅助概念设计开辟了一条途径     

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。     

大天区多目标光纤光谱望远镜装拆机器人概念设计

阐述了概念设计的重要性,并以大天区多目标光纤光谱望远镜装拆机器人为例,介绍概念设计的内容、步骤和使用的工具.     

A Conceptual Approach to Integrate Design and Control for the Epoxy Dispensing Process

Performance improvement of manufacturing systems in the semiconductor industry involves interdisciplinary expertise, such as physical modeling, mechanical design, electrical control, and even material science. Integration of these different disciplines is a challenging problem in the semiconductor industry. The paper presents a conceptual approach to integrate design and control methodology for complex processes with specific application to an epoxy-dispensing control system – a critical equipment in the semiconductor packaging process. This methodology includes three hierarchical levels: process design (system-level and component-level), multivariable control and the statistics-based supervision. This paper deals with conceptual design at system-level by integrating an approximate model with an axiomatic approach, and briefly introduces approaches at other levels. In the conceptual design at system level, the primitive model of the system is sufficient to show some basic properties of the process, by which the axiomatic design can be easily integrated to evaluate the system design and suggest an optimal system configuration with invariant properties to internal variations. Under minimal internal variation, the multivariable control that is intended to suppress external variations can be approximately constructed by a set of independent controllers. Statistics-based supervision will provide suitable setpoints for the multivariable control so as to maintain good performance in the dynamic environment.     

概念设计中的功能方法树

在介绍功能方法树基本原理、组成及两种扩展方法的基础上 ,提出功能方法树可采用自顶向下的方法建立 ,并提出了建立功能方法树的手工方法与用于软件编程的算法 ,实例表明其手工方法在产生多个设计方案时简单实用     

机械产品概念设计:综述与分析

从概念设计在设计过程中所处的地位入手 ,指出模型问题和推理问题是机械产品概念设计过程中遇到的两大难题 ,并详细归纳和分析了目前为解决这两个难题而提出的相关技术或工具的现状和特点     

面向产品概念设计的设计工具选择与应用

本文分析了产品概念设计的特点与重要性,指出合理的选择设计工具对于提高产品开发的效率与质量至关重要。介绍了面向方案创新的CAI设计软件Pro／Innovator与支持三维建模与设计验证的CAD设计软件Solid Works,并通过一工程实例说明两种设计工具的使用很好的支持了产品概念设计过程。     

机械方案创新设计过程模型的研究

本文主要研究机械方案创新设计过程。在简要介绍和分析机械方案设计一般过程和基于结构类型变异机构综合方法的基础上,提出集成功能推理和结构推理为一体的机械方案创新设计过程模型,并在此基础上开发了机械方案创新设计智能支持系统（ＭＣＩＤＩＳＳ）。     

定性推理在产品概念设计中的应用研究

概念设计是产品开发中的一个重要阶段 ,利用定性推理在信息不完全情况下所具有的定性行为预测功能 ,能够部分提高概念设计阶段的计算机辅助设计的水平。文中结合重心稳定问题 ,介绍了一个定性推理原型系统 ,并讨论了其在概念设计中的作用     

产品概念设计网络评价系统的设计与研究

研究网络环境下的产品概念设计是现代 CAD领域的一个重要研究方向。概念设计网络评价系统是产品基于 Internet/Intranet的概念设计不可缺少的重要环节。文中就产品概念设计定量模型和定性模型提出相应的评价方法 ,研究了模糊综合评价网络算法设计和网络评价管理系统设计 ,提出以实例相似度作为概念设计评价选择方案的依据。提出的概念设计网络评价系统在理论和技术实现上具有一定的通用性。