An online ergonomic evaluator for 3D product design

More documents

Recommendations

Info

484 3.2. Web-based GUI The web-based graphical user interface (GUI) is embedded in Microsoft Explorer 6.1 using simple HTML format. Java Server Pages (JSP TM ) technology connects the viewer to multi-media data sources within a browser environment. A variety of languages like JavaScript, VBScript, and DHTML provide effective tools for the GUI implementation in a JSP program. The GUI also enables instant communications between the system and the user with integration with standard Windows UI components. 3.3. Server technology This system adopts Apache Tomcat TM as a web application server that links the 3D viewer embedded in the web-based GUI and the reference engines (posture generator and ergonomic evaluation engine) at the back end. A commercial Java SDK–JXL TM offers an interfacing technology for the data transfer between the viewer and the posture generator constructed in Microsoft Excel TM spreadsheets, or related rule databases. 3.4. Posture generator The human templates produce a variety of postures required in ergonomic evaluation. It is constructed from a massive amount of the body motion data captured with a full-scale high-speed camera. Different patterns of human configuration are recognized from the captured data using data mining techniques [42], andtheresults are stored in Microsoft Excel TM spreadsheets. Each template usually corresponds to a set of coordinate transformations for various body parts involved in the generation of a particular posture. These spatial relationships exist in Excel TM tables and drive the configuration change of the digital human in the viewer through SpinFire SDK and its internal mathematical functions. This posture generator also offers the viewer the detailed dimensions of any chosen human model. It also passes the posture data along with the user inputs over to the evaluation engine. 3.5. Ergonomic evaluation engine The system currently allows ergonomic evaluation for a set of sitting postures using a two-dimensional C.-F. Kuo, C.-H. Chu / Computers in Industry 56 (2005) 479–492 statically biomechanical model. The evaluation result consists of the compression as well as shear forces on L5/S1 and moments/forces at critical joints of the upper limbs including shoulder, elbow, and wrist. The corresponding formulae are explicitly expressed in Excel TM and all the related computations are performed with VBA. The posture generator provides the pose data required in the evaluation through direct binding between two Excel threads. The engine then sends the outcome over to the user via the application server in HTTP protocol. The viewer is running a socket thread pending for the response from the engine. The server will refresh the browser and publish with the evaluation data. Note that more biomechanics models can be readily appended into the engine for other ergonomic evaluations. 4. Implementation and discussions 4.1. Scenario I We illustrate two scenarios that demonstrate on-line design evaluation for ergonomics using the proposed system. In the first scenario, the user remotely opens up a browser embedding with the 3D viewer via the Internet and establishes a HTTP link to the server, as shown in Fig. 4. The main page consists of three modules. The left one (L) provides a set of UI’s withwhichtheusercan query geometric information in the current design. The middle area (M) contains a 3D display space of the viewer and a history data access area. The user can change the pose of the digital human with the joint angles keyed in from the right module (R). The evaluation process generally consists of the following steps shown in Figs. 5–8, respectively: (1) Choose an interior design from the drop down menu in middle module. (2) Generate preferable 3D views and record them for future evaluation. (3) Measure the dimensions in 3D space that determine the comfort of the current interior setting. (4) Calculate the corresponding joint angle (the hip angle in this case). (5) Repeat (4) and (5) for each joint angle (six angles to be determined in this example).
(6) Query the forces and the force moments from the back end evaluation engine. In Step (1), the user can choose a design from different car interior settings residing in a remote CAD C.-F. Kuo, C.-H. Chu / Computers in Industry 56 (2005) 479–492 485 Fig. 4. User interface of the ergonomic evaluator embedded in a browser. Fig. 5. User is selecting a design from different car interior settings. database and upload it to the system for examination (see Fig. 5). Note that the chosen CAD model will be automatically converted into the .3D file format before the upload. The conversion process is accomplished via a publishing program embedded in the CAD sy-
Page 1 and 2: An online ergonomic evaluator for 3
Page 3 and 4: The designer can also use the model
Page 5: calculated after the user has accom
Page 9 and 10: SpinFire TM SDK.Theresultisthencomb
Page 11 and 12: clicking the tabs (in the upper lef
Page 13 and 14: Genaidy, S.S. Asfour (Eds.), Comput

An online ergonomic evaluator for 3D product design

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?