Soonhung Han

Knowledge-based parametric design of mechanical products based on configuration design method

Abstract Parametric modeling and configuration design methods are key technologies for mass customization in manufacturing. This paper describes the parametric modeling process of machine tool, and proposes a framework which parametrically models a machine tool assembly based on a design expert system. The concept of design unit, which is one level higher than functional feature, and the parametric modeling concept with functional features have been proposed. The domain knowledge in the knowledge-base has been mapped to the geometry of the CAD system. A design expert system to redesign assemblies of a machine tool has been implemented, because commercial CAD systems cannot handle the parametric design of assemblies. This system consists of a commercial expert system shell, a design knowledge-base, and a commercial CAD system with an API program. The API program interfaces the expert system with the CAD system through a GUI.

A set of standard modeling commands for the history-based parametric approach

Abstract The current version of STEP standard cannot exchange the parametric information of CAD models. Only pure boundary representations that cannot be parametrically edited are transferable [Geometric Modeling: Theory and Practice (1997)]. There are two approaches for the exchange of design intents such as parameters, features, and constraints. The first is an explicit approach based on constraints between pre-defined parameters and features. The second is a procedural approach based on the sequence of operations issued to construct the models. The authors have previously proposed a macro-parametric approach [International Journal of CAD/CAM 2 (2002) 23], which is a variation of the procedural approach. In this approach, CAD models can be exchanged in the form of macro files, which include the history of modeling commands. To exchange CAD models using the macro-parametric approach, a set of standard modeling commands should be defined. This paper introduces a set of standard commands and explains the process of developing the set.

A method and tool for human-human interaction and instant collaboration in CSCW-based CAD

From human-computer interaction to human-human interaction and from information sharing to instant collaboration are major advances from traditional standalone and distributed CAD to collaborative CAD. This paper explores model, method and tool to achieve this goal. A human-centered collaborative design model to support human-human interaction is presented. A method to transparently add aware capabilities to single-user CAD applications is outlined. Based on the method, an instant collaboration tool is implemented to support human-human interaction in collaborative design process. The collaboration tool involved some core collaborative issues such as agent structure, communication, group awareness, consistency maintenance and collaborative tasks. We also test the method in a 3D collaborative tool for heterogeneous CAD applications.

Mapping product structures between CAD and PDM systems using UML

The product data exchange between heterogeneous CAD and PDM systems is a crucial issue for the integration of product development systems. STEP offers an efficient mechanism of product data exchange between heterogeneous systems. This paper introduces a UML-based mapping methodology for the product data models. The suggested mapping method has been applied to exchange the product structure data between a CAD system and a PDM system. Based on the STEP methods, we developed an interface module.

A method for topological entity correspondence in a replicated collaborative CAD system

In order to utilize the potential advantages of replicated collaborative CAD system to support natural, free, fast and less-constrained multi-user human-to-human interaction, a local-locking mechanism, which can provide fast modeling response, is adopted as concurrency control mechanism for a replicated on-line collaborative CAD system. A human-human interactive modeling is achieved by immediate local execution of modeling operations and exchange of modeling operations across all collaborative sites real-time. In particular, an approach to achieve topological entity correspondence across collaborative sites during modeling procedure, which is critical to guarantee the correctness and consistency of collaborative modeling result, is proposed. A prototype system based on the ACIS geometric modeling kernel is implemented to verify availability of the proposed solution.

Meta-ontology for automated information integration of parts libraries

Seamless integration of digital parts libraries or electronic parts catalogs for e-procurement is impeded by semantic heterogeneity. The utilization of ontologies as metadata descriptions of the information sources is a possible approach to providing an integrated view of multiple parts libraries. However, in order to integrate ontologies, the mismatches between them should be resolved. In this paper, we propose meta-concepts with which the ontology developers describe the domain concepts of parts libraries. The meta-concepts have explicit ontological semantics, so that they help to identify domain concepts consistently and structure them systematically. Consequently, our method ensures that the mismatches between parts library ontologies are confined to manageable mismatches which a software program can resolve automatically. Modeling ontologies of real mold and die parts libraries is taken as an example task to show how to use the meta-concepts. We also demonstrate how easily a computer system can merge the resultant well-established ontologies. c 2006 Elsevier Ltd. All rights reserved.

Protection of intellectual property based on a skeleton model in product design collaboration

As markets are globalized and competition among companies increases, corporations strive to remain competitive by focusing their abilities on key parts of a new product, while outsourcing remaining parts to other companies. In these circumstances, relationships with business partners with regard to product design are not rigid and vertical, but rather, flexible and horizontal; thus, partners today can be competitors in the future. Therefore, the intellectual property of a participating company should be protected from other collaborating companies during the product design process. However, this safeguard should not be an obstacle to product design collaboration itself. As a solution to this problem, we propose a method to share a skeleton model among collaborating companies. By using this model, participating companies can share essential data required for the detail design of those components of a product for which they are responsible, while ensuring security of their intellectual property. The feasibility of the proposed method has been demonstrated through experiments in a development scenario involving a tub component of a washing machine.

Reconstruction of 3D interacting solids of revolution from 2D orthographic views

3D CAD is replacing 2D CAD to improve efficiency of product design and manufacturing. Therefore, converting legacy 2D drawings into 3D solid models is required. CSG based approaches reconstruct solid models from orthographic views more efficiently than traditional B-rep based approaches. A major limitation of CSG based approaches has been the limited domain of objects that can be handled. This paper aims at extending the capabilities of CSG based approaches by proposing a hint-based recognition of interacting solids of revolution. This approach can handle interacting solids of revolution as well as isolated solids of revolution.

Repairing CAD model errors based on the design history

For users of CAD data, few things are as frustrating as receiving unusable, poor quality data. Users often waste time fixing or rebuilding such data from scratch on the basis of paper drawings. While previous studies use the boundary representation (B-Rep) of CAD models, we propose an approach to repairing CAD model errors that is based on the design history. CAD model errors can be corrected by an interdependency analysis of the feature commands or of the parametric data of each feature command, as well as by a reconstruction of the feature commands through rule-based reasoning of an expert system. Unlike other correction methods based on B-Rep models, our method repairs parametric feature models without translating them to a B-Rep shape, and it also preserves parametric information.

An XML-Based Macro Data Representation for a Parametric CAD Model Exchange

AbstractA macro-parametric approach, which is a history-based method of parametric CAD model exchange, has recently been proposed. CAD models can be exchanged in the form of a macro file that comprises a sequence of modeling commands. As a set of event-driven commands, a standard macro file can transfer the designer intent such as parameters, features and constraints. Moreover, it is suitable for a network environment because standard macro commands are open and explicit, and the data size is small. This paper introduces XML technology to represent the macro-parametric exchange. Using XML to represent macro-parametric commands enables the management of a large amount of dynamic content, Web-enabled distributed applications, and the inherent characteristics of structure and validation.