A hybrid case-based reasoning CAD system for injection mould design

Injection mould design generally lies on the critical path of a new product development. The design efficiency will have significant impact on the overall lead time of a new product. This paper presents a prototype injection mould-design system using a hybrid case-based reasoning (HCBR) approach. Case-based reasoning (CBR) is a solving paradigm that uses previous episodes on solving problems similar to the problem at hand (the new problem) as the basis for solving the new problem. In this hybrid system, CBR is incorporated with generalized design knowledge, and provides a flexible and comprehensive model of design. The knowledge base of the system would be accessed by mould designers through interactive programs so that their own intelligence and experience could also be incorporated with the total mould design. The approach provides a workable model of mould design system with CBR and knowledge-based expert system intelligent support, which could suggest good and proven design solutions to new design problems quickly, avoiding the time necessary to create those designs from scratch, for the plastic products manufacturing industry.     

Generating significant subassemblies from 3D assembly models for design reuse

Significant subassemblies are defined as the reusable regions of pre-existing 3D assembly models. A significant subassembly has great significances for design reuse as it aggregates abundant knowledge in a vivid 3D CAD model and enables designers to reuse existing mature designs from a high-level perspective. Consequently, this paper contributes to significant subassembly generation from pre-existing 3D assembly models for design reuse. The paper first gives an explicit definition of significant subassemblies and further explores the multilevel knowledge embedded in these significant subassemblies. Based on the above definition and multilevel knowledge, a knowledge-based approach is then proposed for significant subassembly generation, which includes three phases: (1) identifying candidate subassemblies with high cohesion inside and low coupling outside using the Markov clustering process; (2) removing normal candidate subassemblies with low reusability and less information, and generating filtered subassemblies using the proposed assembly frequency – inverse mean subassembly frequency based scheme; and (3) determining significant subassemblies by measuring the complexity of the filtered subassemblies. Finally, a computer numerical control honing machine model is taken as an application example to demonstrate the effectiveness of the proposed approach.     

突破性创新与突破性创新设计研究综述

目的 将突破性创新设计从突破性创新与创新设计研究中分离出来进行专题分析。方法 采用跨学科横向关联的方法,通过文献检索,分析技术创新管理领域关于突破性创新的研究成果,并归纳了3个主题。分析了设计与工程设计、创新设计的特征,并将创新设计分为3类,其中一类是突破性创新设计,最后对突破性创新设计所涉及内容进行文献分析。结论 实现了Leifer等提出的突破性创新的3个基本特征,这些特征的实现也是突破性创新设计成功的参考。突破性创新设计是创新设计的一类,其关键是通过已有跨学科效应或跨行业技术的搜索与应用,实现核心技术的突破。突破性创新设计过程包括机遇识别、突破性技术实现等关键阶段,在C–TRIZ框架下已构建了几种过程模型,并可供企业参考。技术创新管理领域中关于突破性创新的研究,为突破性创新设计提供特征参考,两类研究属于不同领域,但可形成上下游关系。这种观点为创新设计跨学科研究提供了一种新思路。     

A constraint‐based approach to the modelling and analysis of packaging machinery

To enable packaging machinery manufacturers to compete at an international level, it is necessary to introduce them to more advanced design methods and technologies. For years, the evolution of packaging machinery has relied heavily on trial‐and‐error methods. The demands for continual increases in the performance capabilities of the machines, escalating legislation, environmental directives and changes in the characteristics of the product require rapid development of existing machine designs and the creation of new machines. This paper discusses the needs of SME packaging machinery manufacturers and identifies their requirements for methods in support of the design and redesign of packaging machinery. The need to identify, capture and manipulate design knowledge is critical for SMEs, where all too often design records are incomplete. Furthermore, a systems modelling approach that provides for support over the conceptual, embodiment and detailed design phases is essential for the rapid and effective development of designs. In order to meet these requirements, a methodology is proposed which incorporates ‘constraint modelling’ techniques. The methodology provides for experimental investigation and computer‐based modelling, which together aid the designer in gaining a fundamental understanding of the design problem. This enables the identification and representation of design knowledge, the determination of the limitations of an existing design, the evaluation of alternative designs and redesign strategies, as well as the embodiment, refinement and optimization of design solutions. The theory of ‘constraint modelling’ is discussed and the various phases of the methodology described. The applications of the methodology to a new machine design and a redesign program are also detailed. Copyright © 2001 John Wiley & Sons, Ltd.     

支持概念设计的产品信息网络模型

本文在分析传统产品装配模型的基础上,提出了支持概念设计的产品装配信息网络模型,并提出了功能表面的概念及其应用,指出功能表面与特征之间的主要区别在于：功能表面体现了形状及拓扑结构的不确定性及成长性。基于功能表面的产品装配信息网络模型细致表达了零件与零件之间、零件与表面之间、表面与表面之间的连接关系,建立了零件之间的全相关性。本文讨论了实现该网络结构的理论模型、具体的数据结构和相应的处理方法,为Ｔｏｐ     

Synthesis of feedback-based design concepts for sensors

We explore an approach to synthesize concepts of a class of sensors, where a quantity is sensed indirectly after nullifying its effect by using negative feedback. These sensors use negative feedback to increase the dynamic range of operation without compromising the sensitivity and resolution. The synthesis technique uses knowledge about existing phenomena to come up with an approach to synthesize concepts of sensors and also study their interactions with their surroundings, so as to generate robust designs. The approach uses a database of building blocks which are based on physical laws and effects that capture the transduction rules underlying the working principles of sensors. A simplified variant of the SAPPhIRE model of causality, which also uses physical laws and effects, has been adapted to represent the building blocks. SAPPhIRE model had been used earlier to understand analysis and synthesis of conceptual designs. We have adapted it here for automated generation of concepts. The novelty of the approach lies in the way and the ease with which it constructs a graph which is a super-set of the concept-space. The individual concepts are extracted out of the graph at a later point in time. The extraction of the concepts is done by using a modified breadth-first search algorithm which detects loops in the graph. The usage of breadth-first search algorithm for loop detection is novel, as we have demonstrated that it performs better than depth-first search algorithm for the specific problem. The technique has been implemented as a web-based application. For the sensor problems attempted, a number of existing patents were found that were based on the concepts that were generated by the synthesis algorithm, thus emphasizing the usefulness of the designs produced. The tool generated 35 concepts for accelerometers, out of which 2 concepts were found in patents. The synthesis approach also proposed new, feasible sensor concepts, thereby indicating its potential as a stimulator for enhancing creativity of designers. Automated generation of feedback-based sensor designs is a novel outcome of this approach.     

An option generation and selection methodology for process equipment selection

The option generation and selection (OGS) methodology forms part of a general approach for the design of agile chemical plants based on business, product and process knowledge, with support from information models. This paper describes an equipment OGS tool that encompasses the principles of combinatorial process and plant design. The main components of the methodology are: an equipment option generation model described as a set of objects, and the net relationships between them, and an equipment option selection model which consists of procedures for equipment selection. The two models are supported by databases containing information specific to each equipment type, the concept on which the equipment is based, and relationships with other equipment types. Robust, systematic and complete forms of these models can be used as the basis of an expert system for process equipment design, with equipment selected using these tools satisfying the requirements of both specific processes and families of processes (that contain common features, similar functional groups or similar raw material requirements for process operations). Application of the methodology also allows the evaluation of options for reconfiguring existing plant.     

Optimal design of multi-response experiments using semi-definite programming

Optimal design of multi-response experiments for estimating the parameters of multi-response linear models is a challenging problem. The main drawback of the existing algorithms is that they require the solution of many optimization problems in the process of generating an optimal design that involve cumbersome manual operations. Furthermore, all the existing methods generate approximate design and no method for multi-response n-exact design has been cited in the literature. This paper presents a unified formulation for multi-response optimal design problem using Semi-Definite Programming (SDP) that can generate D-, A- and E-optimal designs. The proposed method alleviates the difficulties associated with the existing methods. It solves a one-shot optimization model whose solution selects the optimal design points among all possible points in the design space. We generate both approximate and n-exact designs for multi-response models by solving SDP models with integer variables. Another advantage of the proposed method lies in the amount of computation time taken to generate an optimal design for multi-response models. Several test problems have been solved using an existing interior-point based SDP solver. Numerical results show the potentials and efficiency of the proposed formulation as compared with those of other existing methods. The robustness of the generated designs with respect to the variance-covariance matrix is also investigated.     

解构主义建筑观对当代展示空间设计的影响

将解构主义建筑思想作为一种设计创新的途径和方式加以分析、消化和利用,使其对发展当代展示空间设计理论和提升设计实践水平起到创新性和前瞻性的推动作用与指导意义。通过文献研究和案例分析,概述解构主义建筑观的时空维度;结合对解构主义建筑师及其作品中蕴含的解构思想和方法的分析,阐述其在当代展示设计中的应用表现,以此拓展和丰富展示设计创意的新途径。解构主义赋予了设计与众不同的灵魂,它的设计思想渗透到建筑、景观、室内空间、服装和产品等众多设计领域,具有完备且独特的理论和实践体系。在解构主义建筑观的影响下,当代展示设计中呈现出建筑叙事性、空间连续性和展示趣味性等特征,颠覆了人们对展示设计的一般认识;也进一步积极推动了当代展示设计的发展。     

Function-based design synthesis approach to design reuse

In this paper, a design reuse framework with a function-based design synthesis approach is proposed in the context of conceptual product development. Previous researches in design reuse have lacked a comprehensive functional base for knowledge representation and reasoning. The method presented in this paper uses a function-based product information model and a multiple objective optimization model to achieve design reuse. The information model is dependent on a functional core which is the key element vector. It is capable of modeling product information with sufficient abstraction, which in turn facilitates intelligent construction of product platforms. The multiple objective optimization method carries out automated design synthesis and evaluation subject to various design constraints. The approach has been applied in the design of the fan filter unit, a key clean room device. It has achieved intelligent design reuse in product conceptual design with significant rapidity and solution variety.     

An approach to functional synthesis of solutions in mechanical conceptual design. Part III: Spatial configuration

These three papers describe an approach to the synthesis of solutions to a class of mechanical design problems; these involve transmission and transformation of mechanical forces and motion, and can be described by a set of inputs and outputs. The approach involves(1) identifying a set of primary functional elements and rules of combining them, and(2) developing appropriate representations and reasoning procedures for synthesizing solution concepts using these elements and their combination rules; these synthesis procedures can produce an exhaustive set of solution concepts, in terms of their topological as well as spatial configurations, to a given design problem.This paper (Part III) describes a constraint propagation procedure which, using a knowledge base of spatial information about a set of primary functional elements, can produce possible spatial configurations of solution concepts generated in Part II.     

Web-based configuration design system for product customization

In mass customization, web-centric knowledge-based configuration systems have become an important tool to help customers configure products that satisfy their different needs and the complex configuration constraints of a product family (PF). An effective knowledge representation scheme and the associated reasoning mechanisms are essential for the success of these systems. This paper presents an object-oriented approach that integrates the functional and structural models of a PF with design process knowledge. Invasion-based search algorithms are proposed to deal with different situations in product customization and heuristic knowledge is introduced in these algorithms to improve the search efficiency. Optimization models have been constructed in terms of customers’ preferences to provide them with the highest satisfaction in product customization. Based on the representation scheme and reasoning algorithms, a web-based configuration system prototype is developed to support product customization. An example of a bicycle family is used as a study case and described in details.     

Knowledge-based functional design of industrial robots

This paper presents an expert functional design model and software modeling environment for designing the architecture of industrial robots. The modeling environment comprises an integrated knowledge base, an inference engine, a working memory, and an explanation unit and is implemented in CLIPS. The functional design model is based on the authors’ behaviour-driven, function-environment-structure (B-FES) formalism, which has been tailored to meet the special requirements of industrial robot design. A universal robot template has been created and a library of typical components of a robot has been compiled. Nine customized templates were generated from the universal template. Web links to the websites of manufacturers/suppliers provide easy access to data on robot components. The architectural design solutions are assessed by a set of user-defined performance criteria, such as precision, flexibility and short cycle time. Application of the approach is demonstrated through a case study of the functional design of a printed circuit board assembly robot. The authors argue that this approach is new for configuring robots and can significantly reduce the time, effort and number of errors made.     

Simulation of a multiterminal system for container handling

A generic simulation model structure for the design and evaluation of multiterminal systems for container handling is proposed. A model is constructed by combining three basic functions: transport, transfer, and stacking. It can be used for further detailing of the subsystems in the terminal complex while preserving the container flow patterns in the system. The modeling approach has been applied to the complete set of existing and future terminals in the Rotterdam port area, using forecasts of containers flows, statistical data from existing terminals, expert opinions, and conceptual designs of the new port area called “second Maasvlakte”. Experimental results including the requirements for deep-sea quay lengths, storage capacities, and equipment for interterminal transport are shown. Further traffic flows on the terminal infrastructure are determined, and the consequences of applying security scanning of containers are evaluated.     

功能树相似推理过程的可视化方法研究

相似推理能够丰富功能树包含的设计信息,提高获得创新性设计解的可能性。该文对可视化技术如何更好地辅助相似推理展开了研究。首先,确定了功能树与可视化模型之间的映射规则;其次,针对相似推理不同阶段提供了相应的可视化人机交互手段,以实时跟踪相似推理过程;最后,通过系统实例进一步验证了相似推理的有效性以及可视化辅助下相似推理效果的提高。     

Adaptive mesh generation based on multi‐resolution quadtree representation

An advanced CAD model is required for efficient, real‐time adaptive generation of FE meshes. In this paper, a discrete level of detail (LOD) method for reconstructing progressive multiresolution models is proposed. With this approach, the model is reconstructed a priori so that any level of detail can be accessed directly, in real time, according to application requirements. The mesh is generated adaptively according to geometrical or analysis error indicators, where even at lower levels of resolution, critical areas are preserved. The method has been extended to progressive time and geometrical models for simulation and is demonstrated by several examples. Copyright © 2000 John Wiley & Sons, Ltd.