Knowledge Engineering Final Project

Online Product Ergonomic Evaluation Program Student: Steven Kuo, Brian Lin

Advisor: Amy Trappey

Abstract We built an online product ergonomic evaluation program to support designers and enterprise to introduce human factor issue into the product development. By using the program we can get dimension data from a product 3D model and assign it to relative parameters in a virtual human body. It’s mean we can extract ergonomic information from the geometric model of product. The information provided by the system is produce by a posture produce engine and ergonomic evaluation engine. Depending on the report comes from system designers can evaluate they conceptual design in the easily stage of product life cycle.

1. Research motivation and objective 1.1 Research motivation One of the consequence of automation and the industrial revolution is the change of working properties. Machines and equipments substitute the manpower to do some complicated assignments. All people have to do is to operate equipments, monitor the process, and survey the outcomes. According to some drivers’ experiences, it will be found that some design signatures are not suitable for employ. When people control in a cabin, first, the feeling of discomfort may occur because of the bad design of the operation space, and then the controlling performance may go down. In the course of time, some diseases will occur. Therefore many transportation cabin designers try to evaluate the disposition of equipments of the cabin to keep drivers postured well by using “general package factors” which is a method to represent the structure of the cabin with a single number (SAE, 1980). But it’s a time-consuming and costly work to develop and carry out a new ergonomic evaluation system. Furthermore, designers have to learn how use the new system and to be used to it, but most of the engineers won’t accept a new system and exclude it. Even if the evaluation is contracted by other companies of system engineering, the cost, the time of communication between designers and system engineers also have to be considered. For these reasons, in this research an automated decision support system based on WWW is developed to solve such kind of problems. 1.2 Research objective At the step of concept design, a designer needs to consider many aspects of the design, especially at the view of human beings. The system can help designers evaluate their conceptual designs previously and apply the result in the final product. The most important objective of our research is to help create a suitable design for human beings, so we evaluate the design from the angle of biomechanics and RULA which can be used to find out some evaluation index.

1.3 Research architecture

Confirming the title

Build up the web-based system

Searching for references and relevant studies

Research methodology

System Analysis

System Implementation

Conclusion and Discussion

Chap 2

Chap 3

Chap 4

Chap 5

2. Background It’s so hard to find a perfect seat because of the differences between individuals. But there are some principles which can be applied to make a better design. The first one is to promote the presentation the posture of lordosis which is the posture as standing. When the seat backrest angle is 90o, the effect of promoting lordosis is significant (Andersson, 1979). And if the backrest is at the angle of 110o, the curving direction of the spine is very similar to it as standing. Secondly, the designer has to consider whether the seat could reduce the pressure of disks. Similarly, if the seat backrest is 100o to 110o, the significant utility will occur (Andersson, 1987). Furthermore, there are some other principles, such as minimizing the static loading of the back muscles, reducing postural fixity, and providing for easy adjustability. Besides, seat height, slope, depth, and width, contouring, and cushioning should be considered as possible as designers can. In order to evaluate the design with these concepts, some occupational biomechanics models are put in use and the designers can find out the suitability of designs for human beings.

3. System Analysis 3.1 Implementation tools What tools we used in this project 1. Apache Tomcat Server 2. Microsoft Active Server Page 3. Actify SpinFire Viewer 4. Acitfy SpinFire Professional Plus 5. Java Script 6. JSP 7. JXL 8. Microsoft Excel 9. Macromedia Dreamweaver MX 10. 3D StudioMax 3.2 Job Assignment

Teammate Job content

Steven Kuo ‧ Evaluation engine design and implement ‧ Viewer program implement ‧ Interface design

Brian Lin ‧ Excel connection ‧ Evaluation engine implementation ‧ Interface design

3.3 System Introduction

The System mainly contains two major parts- Mode A and Mode B. The methodology and architecture we introduced are embedded in the Mode A application. The Mode B is a more intuitive application on product’s ergonomic design. Mode A

Using the system we can get the dimension of a product 3D model like the car interior and assign the dimension to relative parameters of a virtual human body.

First, users can define the personal view angle by the section of viewpoint setting area, drag the view to a certain angle, give a name to it, and press button to record it. Later you can switch easily amount the defined viewpoints.

Next users can make note to a certain part of product or directly put the note in the space for communication or record use. But get the useful dimensions in the CAD model is the most concern in this case, we can catch the coordinates of a certain point and the distance between features, angles constructed from three points. In this case we can try to study the reasonable adjustable range of a car seat design.

We have already imported three different angle types of the seat. And then we use the function to get the angle and record it to the section here and pass the value to certain angle of the joint here we assign it to the L5S1 position which we concern most in the Ergonomic study. After the operation we can send the data to the reference engine behind for the calculation of each joint’s strength. After the process, we can get the posture information under interior A, B, and C. Most significant is the compression and shear force. By the system designs can get ergonomic information from the 3D CAD model.

System - Mode A

Mode B Mode B use the intuitive way let designers manipulate the product component to fit

the virtual human body we imported. For this instance, we imported the human height 173 centimeters and weigh 60 kilograms. In the future we can let different size of human body available for the system, like section on the left screen. Select the gender and the percentage of target user, and import to the product CAD model for evaluation. And then you can translate or rotate the component of the product to fit the target user. Further more users can save the change and use Mode A to get more detail information in quantitative may.

System - Mode B

3.3.1 System Architecture ‧System architecture graph

In fact, the system can be separated to two parts. The knowledge-based model is the server end, and web-based interface is the user end. Users do some operations on the interface and the server end will achieve the data entered by users. After calculating the result, server end will send it back to users. Furthermore, server managers can manage users’ data with SQL database. (Microsoft Excel file can be put into SQL) ‧ 3D Viewer

-SDK Introduction This package provides all the tools and the documentation you need to integrate SpinFire Viewer technology into your desktop or Web application. This documentation provides tutorials, complete application code samples, and a detailed explanation of the API provided by the Actify components included in this kit.

SpinFire technology is deployed with COM (Component Object Model)

components. This allows easy integration in numerous development environments including Visual Basic, C++, JavaScript, Delphi, etc.

The SpinFire Viewer is implemented by a main component called XView3D XView can be used inside Web pages, as a plug- in, as described in the "Tutorials" section of this manual. It can also be used as ActiveX component inside traditional applications, as described in the included Visual Basic and C# samples. This document provides all the details needed to use XView3D and its API.

-Translator SpinFire Professional Plus adds the ability to import native CAD files from the

major CAD suppliers, including Catia v4, Pro/E, Unigraphics, I-DEAS-Web Access, SolidWorks, Solid Edge, Parasolid, Inventor, and Step

SpinFire Professional supports all major CAD systems without additional software or infrastructure, providing a universal visualization solution for CATIA, PRO/E, Unigraphics, SolidWorks, Solid Edge, Mechanical Desktop, SDRC, AutoCAD DWG/DXF/DWF, AutoDesk Inventor, Parasolid, SAT, IGES, STL, STEP, VDA, 3DStudio, ISO G-Code, HPGL, and VRML.

Actify 3D Viewer

‧ Data transmission

Because of the use of JSP for the web page, a special API named JXL is applied to connect the JSP web interface and excel file of biomechanics. Similarly, JXL is used to show the result back to the user. With the API, formulas, values, and relationships can be transferred to the format of JAVA.

‧ Posture Produce Engine

In this paper we present a general method for rapid prototyping of realistic character posture. We solve for the natural motion from a simple posture template provided by the motion capture system. Our framework can be used to produce relatively complex realistic motion with little user effort. We describe a novel constraint detection method that automatically determines different constraints on the character by analyzing the input 3D CAD model. We show that realistic motion can be achieved by enforcing a small set

of linear and angular momentum constraints. This simplified approach helps us avoid the complexities of computing muscle forces. Finally, we show that by learning a small set of key parameters that describe a character pose we can help a non-skilled designer rapidly create realistic character posture under specific design.

Posture Produce Engine

Transformation Function for Posture Produce Engine

‧ Ergonomics Evaluation Engine

In a IOSH’s study on lifting aids for manual handling, the injury occurred at low back is 57% which is the highest percentage among all those workers who have musculoskeletal disorders. In another investigation on manual material

handling[] conducted by IOSH, it shows that 90.7% workers complain low back pain, and the lifting action is a great part of their daily handling activity. Also, based on an American statistics, the cost of these injuries is in excess of 30 billion dollars per year. Low back pain (LBP), however, is one of the major harm of manual materials handling. Severely musculoskeletal disorders often occur in heavy- load occupations because of poor postures and overload. How to evaluate the risk of manual lifting has become a very important issue.

Besides NIOSH guidelines and lifting equation which shall propose working guide and recommended weight limit, only a few method is available and can be used easily for onsite evaluation of manual lifting. In this study, a series of evaluation diagrams used to assess the working postures is established. Based on a two-dimensional statically biomechanical model, the compression stress on L5/S1 is calculated for various lifting postures and loads by applying anthropometry database of domestic worker population. The developed diagrams can be applied easily to risk evaluation of low back pain for manual lifting and other symmetrical working postures, and provide guidance to reduce low back pain occurrence on workplace.

Chaffin’s Biomechanical Model

‧ Posture Information

With the mechanism of “Ergonomics Evaluation Engine” which base on biomechanical model used frequently in human factor field, we can assessment human joint’s strength interactively. What designers can get is the strength information about L5S1 compression and shear force, the reactive force and moment of elbow, shoulder, hip, knee, ankle, and toe. By comparing different value on those part designers can reference the ergonomic design of different concept, and raise more quantitative evidence from the system.

Ergonomic Information Page

3.3.2 Mode A Operation Procedure Using the system we can get the dimension of a product 3D model like the car

interior and assign the dimension to relative parameter of a virtual human body.

Ergonomic Evaluation Engine

Select 3D model

Define viewpoint

Get dimension from 3D model

(3pt angle)

Record the dimension data

Assign to virtual human body

(L5S1)

Send data to Evaluation Engine

Body joint strength information

3.3.3 Mode B Operation Procedure Using the intuitive may the system can let designers manipulate the product component to fit the virtual human body we imported.

Select 3D model

Joint product and user model

Set translation amount

Set rotation amount

Export the changed product model

Import user model

Component translate

Component rotate

4. System Implementation 4.1 Mode A Operation Illustration 1. Mode A operation main window

2. Select the model you want to evaluation

3.Define the personal viewpoint

4. Use the “3pt Angle” function to get the information on the car seat

5.Get the value of the cat seat angle and record it in the left hand side textbox.

6. Press the angle on the virtual human body and assign the value to it.

7.Finish all the information collect form the car interior and send the information to the reference engine behind.

8.Get the biomechanical information about the posture under design B.

4.2 Mode B Operation Illustration 1. Mode B operation main window

2. Import a target user from the virtual human database

3. Define the personal viewpoint

4. Pick on the component you want to manipulate

5. Set the translation unit

6. Translation along X, Y, and Z to fit the user

7. Set the unit of rotation

8. Rotate about X, Y, and Z to fit the user

5. Conclusion and Future work 5.1 Conclusion To get information from product 3D model is the objective of this project. We try to link product geometric data with human posture in order to retrieve ergonomics information. By achieving this goal, the system provides an online ergonomic expert available for R&D department and designer in enterprise. This system is a more economical method to introduce human factor concept into a company. When a designer uses the system, he has to know the clue in the design object’s geometric data, and the target user’s definition. Then they can apply these ergonomics data into the product and develop more humanistic product. 5.2 Future work We have some ideas about the future research. Some of these ideas came from the application in this project. In the project we intent to show the concept of “building a human’s posture from the clue of 3D model” more complete, but only can implement a part of it. We hope to do more study in the motion construction aspect, which has its roots in a variety of research areas ranging from robotics and spacetime optimization to biomechanics and kinesiology.

Literature [1] Chaffin, D.B., Andersson, G.B.J., 1991 ; “Occupational Biomechanics,” 2nd ED.,

John Wiley & Sons, Inc. [2] Chaffin, D.B., and Baker, W.H., 1970; “A Biomechanical Model for the Analysis

of Symmetric Sagittal Plane Lifting ” AIIE Transaction, 2: 16-27. [3] 陳志勇，1998；“人工搬運作業省力化可行性研究”，行政院勞工委員會勞工安全衛生研究所研究報告，IOSH87-H326。

[4] 李正隆、王茂駿，1995；“物料搬運工作危害性電腦化評估系統研究”，行政院勞工委員會勞工安全衛生研究所研究報告，IOSH84-H327。

[5] National Institute for Occupational Safety and Health, 1981; “A Work Practices Guide for Manual Lifting,” Tech. Report No. 81-122, U.S. Dept. of Health and Human Services (NIOSH), Cincinnati, OH.

[6] National Institute for Occupational Safety and Health, 1994; "Applications Manual for The Revised NIOSH Lifting Equation," DHHS (NIOSH) Publication No. 94-110.

[7] Mark S. Sanders and Ernest J. McCormick, 2000, Human Factors in Engineering and Design 7th edition

[8] Don B. Chaffin, Gunnar B. J. Andersson, Bernard J. Martin, 1999, Occupational Biomechanics 3rd edition