INTERNET-ENABLED VIRTUAL PROTOTYPING WORKBENCH FOR FLUID POWER SYSTEMS S.C. Fok, W. Xiang & F.F. Yap School of Mechanical & Production Engineering Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798
[email protected]
ABSTRACT This paper discusses the development of virtual prototyping tools for fluid power systems to minimize the development time, cost and risk. The requirements for the deployment of virtual prototyping tools in terms of the communication of information from the perspectives of designers and manufacturers are presented. The importance of the Product Family Architecture (PFA) reflected by these requirements is discussed. A search function within the PFA is proposed. This "Search Engine" is developed to facilitate the location of appropriate components among manufacturers across different geographical regions. The paper also presents an integration of the proposed "Search Engine" with a workbench for performing the virtual prototyping activities. This work constitutes initial effort towards an Internet-enabled virtual prototyping workbench for fluid power systems. Future effort will focus on the computerized tools to support the assembly and analysis of the design and validation of the workbench for the virtual prototyping of complex fluid power systems.
KEYWORDS: Virtual prototyping, Design 1. INTRODUCTION Virtual prototyping can be viewed as a computeraided design process, which employs modeling and simulating tools to address the broad issues of system layout, operational concept, functional specifications and dynamics analysis under various operating environment. This digital design approach is based on the generation of computer models of products or systems using advanced modeling, simulation, and interactive user interface techniques. The main advantage of virtual prototyping is that systems can be designed, tested and modified without physical testing, thus saving time and cost throughout the design and manufacturing process. Using current technologies, physical prototypes can be realistically represented by virtual prototypes, which are utilized to verify design performance, identify design problems,
and evaluate alternatives. In terms of fluid power system design, simulating complex circuit designs under different environmental conditions is more cost effective and the analysis can be more comprehensive than testing physical prototypes. Furthermore, with virtual prototyping, the time for product realization can be tremendously shortened. This is an increasingly critical factor. Many companies have realized that the first to get the new product to the market often wins the race. At present, many research projects are underway to make virtual prototyping a standard tool in the design arsenal [1-6]. For examples, Haug et al [2] had illustrated an integrated design environment for the virtual prototyping of vehicles while Zamora [5] had significantly improved the understanding and application of drilling fluid rheology and the hydraulics of oil-based and synthetic-based muds using virtual rheology and virtual hydraulics. Xiang et al [7] had recently reviewed the research and development in the computational tools for fluid power system design. The study indicated that there is very little work on the development of virtual prototyping tools for fluid power systems. The challenges for virtual prototyping of hydraulic systems are numerous and the organizational structure to achieve rapid deployment must be based on the fluid power system requirements. This article examines these requirements for the development and deployment of virtual prototyping tools, in terms of the communication of information, from the perspectives of designers of fluid power systems and manufacturers (suppliers) of fluid power components. Based on the requirements, the need for a Product Family Architecture (PFA) is highlighted. A proposed search strategy within the PFA was developed to assist the designers in the search for appropriate components. The paper also presents an integration of the "Search Engine" with a proposed workbench for performing the virtual prototyping activities. Conclusion and future work on the development of the workbench are given.
2. PROTOTYPING REQUIREMENTS IN TERMS OF INFORMATION FLOW The advancement of information technology has revolutionized the design approaches and will greatly influence the development and deployment of prototyping tools for fluid power systems. The development of a complicated hydraulic system could require many different types of knowledge. It is based on a complex interdependency between many individuals, including designers, manufacturing engineers and suppliers. To minimize the development time, isolated experts must be linked to allow them to collaboratively develop the system. Suppliers must be able to provide up-to-date and advanced information on their products to the designers. Engineers must be able to inform the designers about manufacturing problems associated with the designs. To permit these experts to use tightly focused expertise to produce more advanced systems quickly, the use of the Internet is inevitable. The main advantages of using the Internet as the medium of communication, from the perspective of the suppliers and designers, include the following: 1.
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Designers are free to choose when and where to work. They are not confined to an eight to five routine in an office. The Internet allows communication of ideas among designers from different part of the world. It also allows collaboration between designers, manufacturing engineers, marketing personnel to evaluate the virtual prototypes. Designers can share the usage of computer aided prototyping tools through the Internet. Manufacturers can tap into the global market of Internet users via e-commerce. They can potentially market their products to anywhere in the world, 24 hours a day, 365 days a year. Manufacturers can advertise/promote/display their wares for all to view/manipulate. The information is available 24 hours a day and data can be updated as and when required. Manufacturers can use the Internet information to provide real-time manufacturing, logistic support and business services right at the customer’s doorstep.
It is envisaged that the Internet will be the main communication environment for future virtual prototyping activities. To effectively utilize the Internet for this purpose, the complexity of the information grid should be reduced. One way to do this is to examine the main requirements for the virtual prototyping tools in terms of designers' and manufacturers' perspectives. These would include the following:
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To assist the designers to design the circuit. These would include tools for collaborative design, suggestions of hydraulic circuit configuration, and the building of a virtual prototype from basic virtual components. To assist the designers to analyze the design. These would include tools for component sizing, dynamics analysis, and geometric evaluation. To assist the designers to source for appropriate components. These would include tools for component searching and recommendations. To assist the manufacturers to sell their products. These would include e-marketing tools that can be interfaced with electronic-catalogues, which supply relevant product data for customers. To assist the manufacturers in the product life cycle support process. This would include tools for the fault diagnosis and maintenance of components. To assist the manufacturers to coordinate their manufacturing and distribution processes. These would include tools to integrate their enterprise resource planning and supply chain management systems with e-commerce facilities.
The Internet-based virtual prototyping process would create new paradigms for interaction between designers and manufacturers. Based on the above requirements, the convergence of computer networking and telecommunication technologies between fluid power system manufacturers and designers must be resolved for the development of virtual prototyping tools. Figure 1 illustrates the information flow within the web-based hydraulic system virtual prototyping process between the manufacturers and designers. The information framework in figure 1 would provide designers the ability to electronically customize virtual prototypes of their designs through the Internet and receive real-time responses regarding the prices and delivery dates for the desired hydraulic components along with the 3dimensional images and performances of the customized designs. If these performances and terms are acceptable, the designer can place an order to the manufacturer, who can utilize the business information for production planning. Through this process, virtual prototyping would provide the data to manufacturers for their resource planning to reduce costs while allowing interaction between designers and engineers to collaboratively develop the system. In this aspect, the shared knowledge base of figure 1 should be established to facilitate continuous process improvement and should be organized as a repository for technical information, business performances and customer feedback. Figure 1 shows that to match the needs of the designers and the manufacturers, there must be a strong information infrastructure to advance the design communication
between the designers and the manufacturers. This information support is provided by the Product Family Architecture (PFA). Internet Information Flow Designer’s requirements information
Business information
Virtual Prototyping Product Family Architecture
Logistic information
Logistic
Suppliers & Manufacturer Shared Knowledge Base
Manufacturing and Assembly information
Fig1. Information flow for the web-based hydraulic system virtual prototyping process
First Part Query Main Form
Manufacturer Login
Valve Component Selection Browser Pump Component Selection Browser
Ordering Code Selection Browser
Variable Entry 2
Other Standard Components Selection Browser Query
Changing Database
Second Part Query
Variable Entry 1
Update/Edit/Add/Delete Entries
Query
JDBC Connectivity
Database: Sybase SQL Anywhere 5
Limited Access of Database by Manufacturer
Result Transmitted Back
Fig. 2. Flow diagram of a Search Engine The main objective of the PFA is to provide for the informational-linkage between the designers and the manufacturers. This can be accomplished using webbased system tools to match designers’ needs to the capabilities and features available in different fluid power component groups. The information required can include cost evaluation, and technical analysis of compliance and compatibility between components within the design. A standard structure of this PFA has to be defined by the manufacturers in consultation with the designers, taking into consideration the functional difference of various types of standard hydraulic components. Without a common PFA structure, it will
be difficult for a designer to search and locate suitable component models from among the collections of different manufacturers on the information highway. One of the functions in the PFA is to provide a search engine feature for designers. Figure 2 shows the flow diagram of a proposed search engine. In this framework, several manufacturers and designers could cooperatively work together concurrently. This would allow the active sharing of information. In this aspect, a common database structure would minimize the time and effort to accomplish the required search. Currently, the framework has been implemented for some hydraulic pumps and valves and it can be completed
with some other component groups in future work. The first part will enable the designer to enter the working search engine is divided into two types of queries. The 3D virtual model of a control valve VRML Viewer: Cosmo Player
Control panel of virtual workbench
Search engine
Fig. 3 Screen Shot of Integrated Search Engine and Virtual Workbench parameters (e.g. working temperature, fluid viscosity, etc.) of the component. Using these parameters, the program will generate the appropriate SQL (Structure Query Language) statement to retrieve the relevant data. A dialog window of the appropriate component will show the user the results of the search. The dialog window has a browsing feature to enable the designer to look through the results and select the desired component. The second part of the search engine will enable the user to browse through the ordering code of the component. The developed structure has an added feature for manufacturers to update their product online. Each manufacturer will need to enter a manufacturer code as well as a password to gain limited access to the database. Manufacturers will only have the ability to change and update their product databases.
3. USING THE RETRIEVED INFORMATION FOR VIRTUAL PROTOTYPING With the development of the proposed "Search Engine", the next process is to use the retrieved results for assembling the virtual prototype. This task can be accomplished within a virtual prototyping workbench. Figure 3 shows a simple integration of the "Search Engine" with the virtual workbench. The workbench s developed using VRML (Virtual Reality Modeling Language) and Java. VRML is used to create the virtual environment. The Java applet and the VRML scene are
embedded in the same web page. The External Authoring Interface (EAI) of VRML is employed to allow a two-way communication between the Java applet and the VRML browser plug-in. The final results from the "Search Engine" are listed in a separate dialog window. The designer can select the required component from this list. The designer can view the 3-D model of the component using the VRML viewer before making a decision. Selected components can be assembled within the workbench to form systems. The interactive 3D-animation environment of the workbench will enable the designers to rapidly and visually develop the system prototype with full 3D user-interface utilities, i.e. through the manipulation and assembly of the 3-D virtual components. With the proposed framework, it is possible to realistically represent physical prototypes by 3-D virtual prototypes, which can be utilized to verify design performance, identify design problems, and evaluate alternatives. To fully implement the proposed framework will require a systematic approach, tremendous model development efforts, software developments, and closed cooperation between manufacturers and designers. The main issues in the future development of the workbench include: •
Encoding the dynamics, structure, and product data of the hydraulic component within the 3-D model, integrating the information, and transforming the virtual model into a database entity
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The standardization of the organization of the databases of different manufacturers. Manipulation of 3-D objects with respect to 3-D Human-computer-interaction. Communication and coordination of the various virtual component models within the workbench Evaluation of dynamics, perception of data (e.g. cost) and review of performance associated with the virtual prototype
4. CONCLUSION Virtual prototyping is becoming a key technology in speeding up the product development process. This paper presents a concept of a Internet-enabled workbench for the virtual prototyping of fluid power systems. The fundamental idea behind this development is to integrate product modeling with computer simulation to transform the hydraulic component's data into a virtual model. The virtual model can be transmitted very quickly through the Internet to be used in virtual system prototyping. The prototype system can be manipulated, modified and evaluated directly within the workbench. The data is also reusable. A preliminary implementation of the workbench concept is shown. Successful development of the proposed workbench requires the cooperative efforts of fluid power system designers, manufacturers and researchers. This paper presents the requirements of the workbench from the manufacturers and designers points of views. A "Search Engine" has been developed and integrated with a 3-D virtual environment to illustrate the initial concept of retrieval of virtual components for prototyping. Future effort in the development of the workbench will focus on the computerized tools to support the assembly of the virtual components, the analysis of the design and validation of the workbench performance for the virtual prototyping of fluid power systems for complex tasks.
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