CONCURRENT ENGINEERING: Research and Applications

CONCURRENT ENGINEERING: Research and Applications MEMPHIS: New Framework for Realistic Virtual Engineering Sang Su Choi,1,2 Johannes Herter,1 Andreas Bruening1 and Sang Do Noh2,* 1

VR/CAD Technologies Team, Institute for Graphic Interfaces, Ewha-SK Telecom Bldg., 11-1 Daehyun-dong Seodaemun-gu, Seoul 12-750, Republic of Korea 2 Department of Systems Management Engineering, Sungkyunkwan University, 300 Cheoncheon-dong Jangan-gu, Suwon, Gyeonggi-do 440-746, Republic of Korea

Abstract: In the manufacturing industry, they are using various concepts and solutions in order to reduce time and costs in the product development. This article introduces an approach that enables Virtual Engineering and links engineering applications with Virtual Reality (VR) solutions. Thus an environment is provided to implement virtual design reviews and enable the application of virtual prototyping methods. Middleware for Exchanging Machinery and Product Data in Highly Immersive Systems (MEMPHIS) enables interoperability between the IT infrastructure for engineering and VR applications to interconnect existing information and extend that knowledge to a VR application. MEMPHIS provides several interfaces for integrating commercial Product Lifecycle Management applications and provides enriched VR data in standard formats. Interoperability and enriched VR information during product development can reduce the Time to Market. Development/ manufacturing costs are reduced by avoiding geometrical defects and errors in product design, product assembly, and usability through simulation of product production processes. Productivity can be increased by providing an environment for collaboration where there is convenient and transparent access to the information required for the manufacturing process. Key Words: data exchange, middleware, interoperability, PDM, PLM, virtual reality, virtual engineering.

1.

Introduction

Manufacturing industries desire to reduce the product development period and costs through virtual manufacturing and simulation in all processes of product manufacturing without prototyping. Therefore many different solutions have been introduced to support processes in manufacturing by automation and computerization. These approaches are termed Computer Aided Design (CAD), Computer Aided Engineering (CAE), Computer Aided Manufacturing (CAM), Product Data Management (PDM), and constructing environments by applying new trends and concepts such as Computer Integrated Manufacturing (CIM), Intelligent Manufacturing System (IMS), Virtual Manufacturing (VM), Virtual Engineering (VE). CIM is a system of production management in which the entire production process is computer controlled [1,2]. IMS are high-tech production systems for the nextgeneration and will integrate human, and machine, information and communication technology, and environmental technology to meet the needs of the globalized manufacturing environment in the

*Author to whom correspondence should be addressed. E-mail: [email protected] Figures 1, 2 and 5–13 appear in color online: http://cer.sagepub.com

21st century. It is considered as integrated system that optimizes the relationship between human and machine across an organizations processes from order and design to production and sale [3]. VM is defined as the application of computer models and simulations of manufacturing processes to aid in the design and production of manufactured products [4]. In this article, we propose a system to enable VE that applies Virtual Reality (VR) technology to the manufacturing environment. This will enable virtual design review, simulation on virtual prototypes, and virtual manufacturing, to give users the opportunity to examine the entire process of product development. The time to market can be reduced using a VE system Development/manufacturing costs are reduced by avoiding errors and geometrical defects, by checking errors and defects in product design, product assembly, and usability through simulation of the production process. VE can increase productivity by increasing convenience and security in the cooperative operation environment for geographically scattered people through networked collaboration, thus enriching virtual organizations. GM, Ford, and Chrysler are applying VR technologies for performance testing in automobile design and manufacturing and reducing the overall cost. Fraunhofer Institute for Computer Graphics (IGD), a German research institute for applied research in the field of computer graphics and VR, has been

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developing VE technologies related to the automobile industry [5]. Daimler AG in Germany established an environment that allows many engineers to review design on real-size virtual prototype visualization by establishing a VR center. They are researching serial standardized PDM data sharing with component production companies. BMW actively applies virtual simulation technology to vehicle collision tests. It is reducing education and training costs by applying VR technology to the automotive assembly (e.g., door assembly) process training. In Japan, Toyota, and Nissan instigated digital innovations aimed to reduce the design period and development costs. In Korea the Hyundai motor company applied VE technologies. These included using the immersive Cave Automatic Virtual Environment (CAVE) applied to the design review system and the Power Wall to create virtual prototypes. Samsung Heavy Industries reduced the design and manufacturing period by conducting computer simulation for the shipbuilding processes through 3D digital modeling of products, equipment, processes, and methods. These were applied through a digital integrated shipbuilding methods development project for high profit shipbuilding development. The introduction of VE technologies is cost-effective in projects where a large expenditure of time and effort are required to optimally model products that are becoming more complex, and software required for each step differs. It is difficult to apply VE interfaces that are commonly used in design, simulation, and functional testing due to the varying production scales of different application fields. Research is required to optimize interfaces, exchange data and components in accordance with the rules of each VE system.

ET AL.

2.

Realistic Virtual Engineering

Each VE system consists of four sub-systems. They are virtual design review, virtual simulation, virtual manufacturing, and data exchange middleware. Figure 1 shows each VE sub-system applied across the product lifecycle. The virtual design review system that is used to validate and evaluate the product design by creating a Digital Mock-Up (DMU). It controls the DMU as if it was an actual product. It can apply styling and design steps during the product lifecycle. Designers can observe 3D product images on a large scale, high-resolution display rather like a movie theater, rather than a desktop computer display. The simulation validates the model for product durability and stability by discovering design errors through virtual collision tests and wind tunnel tests. It provides various angled views of the result by displaying virtual wind tunnel test results on real products, or by letting users compare real wind tunnel tests to virtual test results. The virtual manufacturing system can simulate product fabrication and maintenance. Operators can practice by performing production processes and simulating repairs in virtual spaces using semi-sphere-shaped immersive displays and haptic devices in the VR-based product manufacturing training and process assignment system. The product development life cycle can be shortened and costs reduced by VR technology systems. By combining the virtual design review, virtual simulation, and virtual manufacturing systems based on a data exchanging middleware, a test-bed for the design and development of industrial products is constructed. In this article, we will introduce the data exchange middleware to interconnect realistic VE environments and supply them with the data required for their functioning.

Realistic virtual engineering Virtual design review

Virtual simulation

Virtual manufacturing

Data exchange middleware

Definition of product

Styling

Design

Analysis & simulation

Production plan of product

Production & utilization

Product lifecycle Figure 1. Concept of realistic VE. Downloaded from http://cer.sagepub.com by guest on February 26, 2009

Maintenance & repair

Recycling

New Framework for Realistic VE

3.

Middleware for Exchanging Machinery and Product Data in Highly Immersive Systems

The data exchange between them is essential as industries can be involved in the design and manufacturing activities. Most researches are the integration between CAD and PDM systems and the data exchange between CAD and VR systems. The first has been carried out with active research and commercial developments by major PDM development corporations (e.g., Siemens Product Lifecycle Management (PLM) Software, PTC and Dassault System). The latter field has not been developed actively. Only a few researches have been performed until now. Researching on the data exchange between CAD and VR systems, Corseuil et al. presented in the Environment for VIRtual Objects Navigation (ENVIRON) system as CAD to VR data exchange tool [6]. In their paper, they pointed out the critical problem of CAD data’s file size which is too large and complex to be visualized in real-time VR environments. They presented the ENVIRON system as an effective CAD to VR conversion tool for direct data exchange. Von Lukas and Vahl suggested an integrative approach to join the still separate application areas of CAD and VR [7]. To implement common interfaces for the data exchange environment, they used OMG’s CAD Services, an international standard. Raba¨tje presented the possibility to manipulate CAD data in a virtual environment and to integrate these data into a conventional CAD program for further elaboration [8]. Gomes de Sa´ and Zachmann presented several interaction paradigms and functionalities which a VR system must implement in order to be suitable for that application area [9]. They aim on enabling inexperienced users to work with virtual prototypes in an immersive environment and help them experiment efficiently with CAD data. Above researches concentrate on the exchange of detailed geometry data between CAD and VR systems. However, the main problem is related to exchangeability of product meta-data and interfaces between heterogeneous systems. As the research topics are handling only geometry data exchange, other fundamental information such as material of products, structural information etc from the original CAD data are not incorporated in the VR environment. The inclusion of those additional information, important for the visualization in VR, are not within the scope of the topics and would still have to be handled manually. Further obstacles lie in the use of heterogeneous environments inside and between companies. This prevents easy exchange between multiple systems. The variety of software solutions, data structures, and file formats complicate the access or even the synchronization of all data. The communication between all

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systems involved has to be managed via interfaces that connect only two systems directly at the time. We propose the new concept in order to communicate between engineering resources such as CAD/CAE/PDM and VE applications using Middleware for Exchanging Machinery and Product Data in Highly Immersive Systems (MEMPHIS) [10]. It provides opportunities to create and manage virtual prototypes by accessing and homogenizing information. 3.1

Architecture of MEMPHIS

Figure 2 shows the major modules of MEMPHIS separated into core and external components. PDM systems are considered as data sources accessed by the Data Access Layer. Here a set of Data Access Object (DAOs) are used for retrieving and achieving persistence of information [11]. The PDM systems are accessed by their Application Programming Interface (API). The Data Access Layer accesses and transforms the data to an internal model. CAD and CAE data is converted to VR formats by special converters for geometrical conversion and enrichment. VR-specific information is added to the geometrical output linked with the product data from the PDM systems. Semantic heterogeneities are resolved by applying ontologies to the attributive data. A specific module for data security is included in MEMPHIS (3DGuard). The homogenized and enriched data is sent to several clients by a unified Web service interface. MEMPHIS clients are provided with a virtual prototype containing the enriched geometries for realistic VE systems and product data that are both visualized on the clients. In the following sections MEMPHIS server/client is explained in more detail. 3.2

MEMPHIS Server

3.2.1 DATA ACCESS LAYER The Data Access Layer is able to access various data sources. For MEMPHIS, PDM systems are considered to be data sources as they provide product related information, as well as geometries. Data access object are applied to access these systems. This approach allows PDM access via a customized implementation based on the API offered for information access. It provides unified interface for other MEMPHIS modules. This concept is based on the principle that every object of the business model has its own DAO for being instantiated with persistent data. A set of DAOs has to be provided for every data source. For example the SmarTeam_Item_DAO knows how to create a PLM Item out of SmarTeam by using the API of this PDM. A customized implementation of the methods to load and maintain the persistent business objects must be adopted in order to use the

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functionalities of the PDM system. The process of loading data is as follows:

PLM object must be defined individually for every PLM object as well as for every PDM system. A relational database is used to maintain the MEMPHIS objects. This database is accessed by the persistence framework Hibernate [12]. It performs table per class mapping and in this way automatically stores objects in the database. By a generic implementation of Hibernate based DAOs, the effort could be reduced to one single class. As the clients are connected to the MEMPHIS server, the performance bottleneck is at the network bandwidth rather than the data access Hibernate.

. Connect to the data source (PDM System) via an API provided. If no API is provided, connect to the vault directly. . Gather all information needed to create a business object. . Transform the information to the attributes of the business object. . Return the created business object.

This approach requires a static set of business objects able to handle all information in a PDM system. A set of specific DAOs has to be implemented when a new PDM system is integrated with MEMPHIS. The extensions are encapsulated within the Data Access Layer, to minimize the effort required for maintenance and extensibility. The main challenge in the implementation of DAOs is the different structures of the PDM systems. The internal information representation differs from PDM to PDM system. The way to put information in a

3.2.2 MODEL The internal data model is based on PLM Services 1.0 [13]. This service definition, developed by OMG, provides a powerful model that allows the handling of information about products, projects, and also organizations with respect to the entire product lifecycle. The service description is quite exhaustive, as various kinds of information are interconnected when handling product-related data. The data model has to be stable to reduce the maintenance effort and to seamlessly

GUI layer Controller Converter Transfer files PLM object to FX-PLM

Client Storage Web connector SOAP webservices Network Interface layer

SOAP Webservices

Modules

Controller CAD2VR

Session management

Server

Log

Business model Extended PLM service

User management

ID : 0815 Identity management

CAE2VR Geometry

Ontologies

Data access layer PDM system access

Team center

Memphis DB access

3D guard

Samr team Memphis database

Figure 2. MEMPHIS modules. Downloaded from http://cer.sagepub.com by guest on February 26, 2009

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access the various systems. The decision to use a PLM Service-based model was chosen as it is STEP-based, and supported by most major PDM systems. MEMPHIS is designed to bridge various data sources that require a sophisticated and standardized data model to handle most information accessible from PDMs. As the service description is designed to access one single PDM system, not to be the data model of a middleware, some minor extensions have be made. The user data are extended to handle specific userinformation such as passwords and access roles. The following Figure 3 describes the extension. 3.2.3 CONTROLLER The most important part of the server is the controller. The controller has several major tasks such as forwarding requests from the client to relevant components, handling the user management, and selecting the appropriate set of DAOs to handle product data. The controller is implemented as a singleton in a server instance [14]. The controller is responsible for: . session management; . logging; . action management.

The action pattern concept is used to manage the different functions. The process for solving a task requested by a client is implemented in an ‘action.’ The request that is addressed to the server by a Webservice call is translated into an Action. Thereby separation between the request and the actual processing is implemented and other types of interfaces, for example stand-alone clients, can be implemented. Extension

PLM services

MEMPHIS user

Person

Person in organization

PDM assignment

PDM system

Figure 3. Extension of PLM services.

Person organization assignment

Project

Actions are to be granular procedures to perform a specific task. Using this divide and conquer approach, a higher rate of code reuse can be implemented as Actions can use other Actions to perform complex tasks. A common sequence for processing a request is described as follows: The user first has to log into the client to establish a connection to the server. The model of a product or assembly is loaded from a PDM system via the MEMPHIS client. The client next requests a list of organizations (PDM systems) and projects available in the data source. User rights to access the model are validated by user roles stored in the MEMPHIS database. All the necessary parameters are submitted from the client and given to the actions in a dictionary. All actions implement a common interface. The session ID of the client is always part of the parameter-set in order to recognize the client requesting information. The session-ID and the project-ID are submitted to the server to load a specific project and given to the load_project_action. The action DAO is accessed to load the information from the PDM system; this was requested as ‘organization in the first action.’ The DAOs convert the project information to the PLM Service structure and this is returned to the client. The client is able to display this information directly. Client and server exchange serialized MEMPHIS model objects. The only thing required to extend the functionalities is to write a new action. Existing Actions can be called and reused. 3.2.4 ONTOLOGY Figure 4 shows main elements of the Ontology model for semantic integration of the PLM Object. The ontology concept for resolving semantic heterogeneities is pragmatic. Ontology elements are mapped on elements of PLM Objects based on their functionality. Ontology elements are used to resolve the semantics of a

Ontology elements

PLM elements

Ontology

Organization

Superior concept

Project/Item

Concept

Item

Individual

Design_discipline_item_ Definition

Property

Item_version_relationship Item_definition_relationship Project_assignment Project_relaionship

Figure 4. Mapping between Ontology elements and PLM elements. Downloaded from http://cer.sagepub.com by guest on February 26, 2009

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model by representing the elements of the MEMPHIS model at a higher level of abstraction. The analogies for the parallelisms of Ontologies and MEMPHIS model are shown in Figure 4. The Ontology is related to an Organization (Instance of a PLM System) in MEMPHIS. It is the organizing element that groups all the models. There is an analogy between projects and items and concepts on the ontology side. As concepts and Items as well are organized in a graph-structure we can establish a BOM and relate it fully to a concept graph. Items in the MEMPHIS models are seen as abstract representations of elements that are part of a product structure. They are related to each other and can contain attributes. These basic characteristics support the creation of analogies between Concepts and Items. Both define the inner structure of model in an abstract way. There should be one of these abstract elements for all single elements in the Ontology as well as in a PLM model. In Ontologies, individuals are seen as concrete representations of abstract elements. They are related to Design_Discipline_Item_Definition in the Object model; concrete representations of abstract elements in the MEMPHIS model. These are concrete representations (individuals in Ontology language) of concepts. Finally, the property element describes the relationship between connected elements. Property elements from Ontologies are mapped with attributes of the Item object. They define how the relationship looks. For example, Project_Assignment is also the relationship between a Project and the objects on which the work carried out by that project is applied. 3.2.5 CAD2VR CAD2VR is integrated to convert the commercial CAD data to a virtual prototype. The engineers can

ET AL.

easily change the development environment according to the functionality that best suits the task in hand. These have to be converted (encoded) to an appropriate format that can be forwarded to the visualization pipeline in order to bring the CAD data to the VE environments. On request by the MEMPHIS Server the CAD2VR processes the CAD data conversion and automatically performs corrections of the geometry and topology. We used the InterOp of the ACIS CAD kernel from Spatial Corporation (ACIS R16, 2006). The ACIS CAD kernel is an object oriented 3D geometric modeling engine. It provides an open architecture framework for wireframe-, surface-, and solid modeling using a common unified data structure [15]. CAD2VR is not only able to convert CATIA V4/V5, Unigraphics, and Pro/Engineer, but also neutral file formats such as STEP (AP203) and Initial Graphics Exchange Specification (IGES) that allows a broad base for the generation of virtual prototypes (VRML, X3D, COLLADA) for VE environments from tessellated CAD geometry models [16]. Figure 5 shows the process chain of the conversion from CAD to virtual prototype for virtual design review and virtual manufacturing. 3.2.6 CAE2VR Computer aided engineering technology is widely used to design and analyze a model before the production stage. We utilized CAE2VR to access the commercial CAE data in the immersive virtual simulation system. CAE2VR is a kernel for importing commercial data, such as Ensight Gold, Ideas UNV, Patran Neutral, CGNS, Ansys, Diffpack, and netCDF. The CAE file is converted to a VTF file of GLView, a middle exchange file format. The SIMR file changed from a VTF is the final file as the virtual prototype. Figure 6 shows the process chain of the conversion from CAE to virtual prototype for virtual simulation [17].

Example with four polygons

Import

Input CAD files

Tessellation

ACIS Kernel

-Types -Length -Indices -Colors -Normals

Encoding

OpenSG Scenegraph

Input CAD files Figure 5. The process chain of the conversion from CAD. Downloaded from http://cer.sagepub.com by guest on February 26, 2009

Output virtual prototypes for design review and manufacturing

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3.2.7 3DGUARD The protection of 3D data in VE environments is of utmost importance. A large amount of manpower and expertise has to be invested in the creation of these data. Thus VE environments must not only provide innovative approaches to generate and work with 3D data, but also to protect them. The 3DGuard module, which is a 3D watermarking system based on a security policy, is integrated into MEMPHIS [18]. Every CAD file that is loaded or saved is automatically processed by the 3DGuard module. A watermark is implanted into the geometry, which is then exported to the virtual prototype. The integration of the 3DGuard is automated and fully transparent for the user. The user does not have to think about security issues, as these are determined by the MEMPHIS user management. 3.3 MEMPHIS Client The client architecture is composed by three components. There are several GUI forms implemented in the view component. They present the data and capture the user requests. The GUI manager of the view component is the layer between the forms and the client controller. A form sends the user requests to the GUI manager. It forwards the commands to the client controller. The GUI Manager forwards the respective answers to the GUI form that is designated to present these data. The architecture can be extended and modified with little effort. The controller component is the core of the client and the main functionalities are implemented. The user requests are translated and forwarded to the interface. In the other direction the client controller converts the data received from the server. It is then displayed in GUI forms. The connection controller is the layer between the client controller and the interfaces managing the connections to the interfaces. The client is needed to convert and display extended the PLM object: Flexible and eXtensible-PLM (FX-PLM) to the user.

3.3.1 FX-PLM CONVERTER The FX-PLM Converter is a wrapper to the PLM object. A new kind of data based on information provide from the PLM object is created. The reason to create this module was the need to filter information descendant from the PLM object. Once on the PLM object much of the information is irrelevant to the user. 3.3.2 FX-PLM STRUCTURE Generic project structure and relations are presented in Figure 7. This structure is constituted for card nodes and edges. Each node represents a different FX-PLM object. Different colors and icons represent deep level relations between the other nodes. This structure is constituent for five different nodes: Project, Item Version, Item, Design Discipline Item Definition, and Document Representation. Table 1 briefly describes each node. The third component, the WEB Connector, is the interface that receives Simple Object Access Protocol (SOAP) messages. This object invokes methods, and Project

Proj Ass1

Item Version1

DDID 1

DDID 2

DDID 3

Doc Rep 2

Doc Rep 3

Figure 7. General FX-PLM structure.

Example with four polygons

Import

Input CAE files

VTF format

GL View inova (Post-processing)

-Types -Length -Indices -Colors -Normals

Encoding

Convertwiz

Figure 6. The process chain of the conversion from CAE. Downloaded from http://cer.sagepub.com by guest on February 26, 2009

Output virtual prototypes for simulation

Doc Rep 1

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these return vectors, in a serialized XML format, back to the calling object. 3.3.3 COMMUNICATION BETWEEN LAYERS Figure 8 represents a temporal diagram describing communication between layers for loading a project from the MEMPHIS Server. Consider that the user wants to load one project from the server. The GUI layer calls the controller and Table 1. Flexible and exensible-PLM nodes. Nodes

Description

Project Item version

A project is an identified program of work. An item version is a version of an item and serves as the collector of the data characterizing a physically realizable object in various application contexts.

Item

An item is either a single object or a unit in a group of objects. It collects the information that is common to all versions of the object. An Item shall always be classified as part, tool, or raw material.

A design discipline item definition Design discipline Item is a view of an item version. This view definition is relevant for the requirements of one or more life cycle stages and application domains and collects product data of the item version. Document A document representation is one or representation more alternative representations of a document version.

Request project

Request file, session ID

PL

PLM project

File information

ues

t 1°

ct

Request file, session ID n atio form n i File

- ch

unk

1°Chunk -

Req ues t Las t ch unk Complete file

roje

Last chunk

MEMPHIS client

Figure 8. Sequential diagram of communication between layers. Downloaded from http://cer.sagepub.com by guest on February 26, 2009

Web service

Request file, session ID

Req

Mp

Server Web connector

Controller

View

Request file

requests the required project. When the controller receives this call, it understands it needs data, and it calls the WEB Connector, and requests the project and it sends the session identification. The WEB Connector receives that request and requests the MEMPHIS Server via the Webservice to, check if the user has a valid active session. On receiving affirmation it serializes the required project and returns to the WEB Connector. When the WEB Connector receives the data first it de-serializes it to pass data to the layer above, the Controller. This layer is the FX-PLM converter. It stores the new FX-PLM project. The view layer sends data and creates a graphical visualization for the new project. Another case is when the user tries downloading a file for 3D visualization or simply stores it on the local hard disk. This case is represented on the aforementioned figure. When the user invokes the action to download a file, for 3D visualization for example, the View layer informs the controller. It starts to initialize the file transfer module. It requests the controller for information about the file, more specifically its name and size. That information is requested from the controller, which will in turn get this information from the WEB Connector. The WEB Connector passes a request to the MEMPHIS server. The server checks if the session is valid and retrieves the file information. It then requests the file itself. This process needs several steps to be complete. The download is done chunk by chunk. The file transfer module also calculates

Request file, sess ion ID

FX - PLM project

User

ET AL.

Request 1°-Chunk k

hun

1°-C

Request last chunk unk

t ch

Las

MEMPHIS server

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information about transfer rate and bytes transferred, estimating the time to finish the transfer during this process.

4.

Case Studies

This chapter shows case studies of MEMPHIS as an integrated component of the design process. As a sample for a network using MEMPHIS system, we used Team Center by Siemens PLM Software, SmarTeam by Dassault System, and in-house VE applications. Figure 9 shows the overall system architecture of VE. Data from the PDM system is mapped to the PLM Object in order to convert it to a virtual prototype suitable for virtual design review, virtual simulation, and virtual manufacturing system. We describe some cases on connecting to the VE System using data exchange middleware. In the first case, the Bill of Material (BOM) data related to the CAD data and material information in the

PDM system (seen in Figure 10(a)) is mapped to the PLM Object of MEMPHIS as shown in Figure 10(b). The COLLADA file is then created for design review. Computer aided design data as shown in Figure 10(c) is converted into the initial virtual prototype shown in Figure 10(d). Later a realistic virtual prototype is created by additionally mapping material information as shown in Figure 10(e). We are able to use this realistic virtual prototype for collaborative design review with a variety of review environments such as Head Mounted Display (HMD) based on Mixed Reality (MR) as shown in Figure 10(f), desktop computer as shown in Figure 10(g), and Tiled Display (TD) as shown in Figure 10(h). The second case shows that part models from the heterogeneous PDM system as shown in Figure 11(a) and (b) are converted into PLM Objects in MEMPHIS as can be seen in Figure 11(c). It is possible to test usability using Curved Display (CD) and Haptic equipment as shown in Figure 11(d) and (e).

Virtual design review

Virtual simulation

High resolution display

Immersive CAE visulization based on network collaboration

Usability verification

Virtual manufacturing

Virtual layout

Virtual training

Virtual manufacturing environment based on MR/AR Real-time visualization environment

Design review based on network collaboration

Virtual prototype

3D input devices

Virtual material library

3D waterMarking Virtual design review data

Network collaboration

Heterogeneous CAE data

Result of virtual design review

Virtual simulation data

Interface of layout builder

Interface of virtual training

Library of facility model

Library of training scenario

3D watermarking

Result of Virtual simulation

Virtual manufacturing data

Result of virtual engineering

PPR ( ) Data

CAD2VR

MEMPHIS

CAE2VR

Management based on FX-PLM(

)

Security component

Database Mapping to PLM object Ontologies Acquisition of PDM data

PDM

PDM

Figure 9. Virtual engineering workflow. Downloaded from http://cer.sagepub.com by guest on February 26, 2009

Result of Virtual manufacturing

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(b) Television model in MEMPHIS

(a) Television model stored smarteam

(c) CAD model

(d) Raw VP

(e) Realistic VP

(f) HMD using mixed reality

(g) Network collaboration

(h) Tiled display

Figure 10. Case study 1: virtual design review.

(d) Interior design review

(a) Engine stored teamcenter

(b) CAR made by CATIA

(c) MEMPHIS

(e) Curved display

Figure 11. Case study 2: virtual design review.

The third case is a heat flow analysis of a Plasma Display Panel (PDP) for virtual simulation. The PDP was analyzed with ANSYS as shown in Figure 12(a). The results of the heat flow analysis were mapped into the PLM Object, as shown in Figure 12(b). The intent is to analyze potential errors in the product design by visualization of the product’s user interaction using the virtual prototype from MEMPHIS.

This system provides a 3D GUI color-map to visualize the distribution of heat and pressure. Visualization of the air flow of wind tunnel test and cross-section for the visualization of the product section information are displayed on the workbench as shown in Figure 12(c) and (d). The model supports collaboration by synchronization of the data between workbench and desktop.


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(a) Heat flow analysis at the ansys

(b) Memphis

(c) Cross section

(d) Workbench

Figure 12. Case study 3: virtual simulation.

(a) CAD/PDM

(b) MEMPHIS

(c) Process layout simulation

Figure 13. Case study 4: virtual manufacturing.

The forth case is a virtual process layout and manufacturing simulation. Data managed in the PDM system as shown in Figure 13(a) are converted to a PLM Object of MEMPHIS as show in Figure 13(b) and then a VRML is created via CAD2VR. After downloading this file, the process layout simulation is carried out as shown in Figure 13(c).

5.

Conclusions

In this article, we introduced MEMPHIS, data exchange middleware to support realistic VE. It brings several advantages. First, it provides interfaces that

use commercial CAD/CAE/PDM systems in actual industries. Thus we can create a realistic virtual prototype faster, more conveniently and efficiently. We can manage geometric data as well as BOM from PDM. Therefore, the virtual prototype is based on high quality data that is highly usable. Second, we proposed an optimization interface methodology to communicate realistic VE. Third, we developed stable, flexible, and extensible data exchange middleware based on an international standard. In this way we can support heterogeneous systems. Our realistic VE TestBed can be implemented in manufacturing industries such as automotive, ship-building, and home appliances. Product design can be radically improved.


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Competitive advantage is enabled by acquiring and rapidly applying virtual prototype technology to shorten the product’s design lifecycle. It can increase productivity by increasing convenience and security in the cooperative environment for geographically and temporally scattered people through network collaboration. So far, MEMPHIS development mainly focused on virtual design review. We are now enhancing MEMPHIS to manage all of the PLM system’s P3R (product, process, resource, plant) information for supporting not only the virtual design review system but also the virtual manufacturing system. We expect that MEMPHIS can provide extensive support to virtual manufacturing systems using the P3R data.

Acknowledgment This work was supported by the IT R&D program of IMC/IITA (2005-S-604-02, Realistic Virtual Engineering Technology Development).

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Sang Su Choi

Sang Su Choi has been the leader of the VR/CAD team and a senior researcher in the Institute for Graphic Interfaces (IGI) since January 2005. He has been a PhD candidate in the Department of Systems Management Engineering, Sungkyunkwan University since March 2007. During November 2003 and January 2005 he worked as a researcher in INOPS Inc. and developed a commercial 3D CAD Viewer and PDM. Mr Choi gained a Masters degree in Shipbuilding Engineering from the University of Ulsan, Korea. For his master thesis, he performed research in computer-aided process planning and expert system for shipbuilding block assembly. His main interest lies in CAD/CAPP/PLM, collaborative engineering, digital virtual manufacturing, e-Manufacturing, and Virtual Reality.



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Johannes Herter

Sand Do Noh

Johannes Herter, MSc has been a PhD candidate in the Institute for Information Management in Engineering at Karlsruhe University, Germany since September 2007. He is involved in education and research in the field of virtual engineering. Besides this, he is a project manager within international research cooperation with Korean Partners. During June 2006 and August 2007, he worked as a researcher in the Institute for Graphic Interfaces (IGI), the joint venture between the Fraunhofer Institute for Computer Graphics (IGD) in Darmstadt, Germany, and EWHA University in Seoul, Korea. The focus of his research was interoperability between PLM systems and he was involved in the design and development of the MEMPHIS server. Mr Herter gained a Masters degree in Computer Science from Furtwangen University, Germany and a German diploma in Industrial Engineering from HS Offenburg, Germany. He conducted research in the field of 3D GIS (Geographic Information Systems) for his Masters and diploma thesis in Fraunhofer IGD during 2004 and 2006.

Dr Sand Do Noh is an associate professor of Department of Systems Management Engineering, College of Engineering, Sungkyunkwan University (SKKU) of Korea. He is in charge of Center of Excellence by Siemens PLM Software, and responsible for the PACE program of SKKU. His major research areas are Manufacturing System and Integration, Concurrent and Collaborative Engineering, Digital Virtual Manufacturing, Product Lifecycle Management, and Interoperability in engineering software. He joined SKKU in March, 2002 after 5 years as a senior research engineer in Institute of Advanced Engineering, Yong-in, Korea and 6 months in School of Mechanical and Aerospace Engineering, Seoul National University, Seoul as research professor. He received BS in 1992 at Department of Mechanical Engineering from KAIST (Korea Advanced Institute of Science and Technology), Taejon, Korea, and MS in 1994, at Department of Mechanical Design and Production Engineering from Seoul National University, Seoul, Korea. And he gained a PhD degree in 1999 at the Department of Mechanical Design and Production Engineering in Seoul National University, Seoul, Korea.

Andreas Bruening Andreas Bruening, Dipl. Ing., works as a software developer for the German company VetZ GmbH since 2008. He is responsible for image processing and 3D applications in veterinarian software systems. From October 2006 to October 2007 he worked as a research associate in the Institute for Graphic Interfaces (IGI) in Seoul, South Korea. The topic of his research was the interoperability between different PLM systems. Therefore he designed and developed the client part in the MEMPHIS system. Mr Bruening graduated from the University of Technology, Business and Design in Wismar in 2006. His degree is Diploma Engineer of Multimedia Engineering. The topic of his diploma thesis can be found in the field of augmented reality and edge detection for the Computer Graphics Center (ZGDV) in Rostock, Germany.


CONCURRENT ENGINEERING: Research and Applications

CONCURRENT ENGINEERING: Research and Applications

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