Study of Method for Computer Aided Ergonomics Knowledge Management

And Design Aiming at Product Design 1Shuxing Du, 2Qijun Wu 1Yunchao Wang, 1Zhenzhen Yi

1School of Mechanical-electronic Engineering, Xidian univ.

Xi’an, Shanxi Province 710071, ChinaDushuxing1119@163.com

2The troops of 93897, PLA Xi’an, Shanxi Province 710077, China

wuqijun1126@163.com

Abstract Ergonomics design is a vital and complex work. In view

of the complexity, multi-factors coupling and fuzziness of Ergonomics knowledge, an Ergonomics knowledge management model unifying modeling and classifying expression has been presented in this paper. A database of physical ergonomics parameters and a knowledge-base of Ergonomics related to product design have been integrated and founded by use of ACCESS based on the model presented. And a Computer Aided Ergonomics Knowledge Management System (CAEKMS) aiming at design has been implemented by use of VC++. By integrating the CAEKMS into universal design software (Pro/Engineer,UG.), it is convenient to query physical ergonomics parameters and manage Ergonomics knowledge during product design, which will improve the product design efficiency evidently.

Keywords: Knowledge Management ErgonomicsProduct Design Computer Aided Design

1. Introduction

Ergonomics is one of key factors contributing to the success of product design [2]-[8]. Overseas Ergonomics has been putting into practice. For instance, England and USA have put forward some systems posing Ergonomics imitating and estimating functions, e.g. PeopleSize 3D human-body and ERGO/JACK etc. The SensAble Technology CO. (MIT) has put forward the interacting 3D equipment (PHANToM) having force feedback and relevant software-developing tools (GHOST).

At home, although the study on Ergonomics and computer aided Ergonomics design have also made some achievements, many problems in practical application still remain to be solved. For example, Ergonomics is restricted to later analyzing, estimating and validating. And the study is more related to specific cases. The problem of communication between Ergonomics and CAD has causes a decrease in usability of Ergonomics software. So, combining the physical ergonomics parameters and the Ergonomics knowledge of complexity, coupling multi-factors and fuzziness, and integrating them into the course of product design so as to

instruct and check the function design and other contour design when necessary, which will be in favor of improving design efficiency. So, an Ergonomics knowledge management model, namely, the method of unifying modeling and classifying expression , has been presented in this paper, And physical Ergonomics parameters base and Ergonomics knowledge base have been found by ACCESS based on the model presented. And a Computer Aided Ergonomics Knowledge Management System (CAEKMS) aiming at product design has been implemented by VC++. With CAEKMS, it is convenient to inquire about physical Ergonomics parameters, to manage Ergonomics knowledge and to implement overall design.

2. Ergonomics knowledge management model

Ergonomics design of product is to design safe, comfortable, economic, pleasing products based on physical Ergonomics parameters and Ergonomics knowledge as well as on the premise that meets the need of essential functions. Ergonomics knowledge is a cluster of knowledge with complexity, multi-factor coupling and fuzziness. Ergonomics knowledge contains both noticeable and non-noticeable knowledge. The noticeable knowledge refers to,for instance, applied principle of main physical Ergonomics parameters ,the ratio of device or tool to the height of human-body(stature), the parameters of visual enginery, perceptive enginery and athletic enginery etc., which can be measured, coded and dealt with by computer. While knowledge relevant to experience, know-how, inspiration e.g., configuration, color, working space design, is non-noticeable knowledge.

So in order to express the availability and embody the commonness and individuality of Ergonomics knowledge, Ergonomics knowledge has been divided into three parts [9],namely, knowledge information, knowledge carrier and knowledge scenario in the paper. It has been expressed as follows, EK= EKI EKC EKS . There, EK is Ergonomics knowledge (name), EKI is knowledge information, EKC is knowledge carrier, EKS is knowledge scenario. The knowledge modeling aiming at the management of Ergonomics knowledge is unifying modeling and classifying expression for knowledge information, knowledge carrier and knowledge scenario.

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2.1 Ergonomics Knowledge Information modeling

Ergonomics Knowledge Information modeling is to describe knowledge briefly and synoptically by using keywords and attributes. The class of knowledge information is a cluster of knowledge information that has the same attributes, which is presented by KI={KIi| 1<i<n}. Modeling includes mainly the name of class-Knowledge-information, the name of attributes and the name of its successive father. It is expressed as follows:

<name of class-Knowledge-information>[:<the name of father>] {the cluster of attributes}

Its attributes include {EK-kind EK-body, EK- procedure }, there, EK-kind denotes the designed-kind, EK-body denotes the parameters in relation to physical Ergonomics , EK-procedure denotes the procedure of design.

This is an example of the Knowledge for meter unit design.

EKI<meter unit >={EKI1< meter shows> EKI2<signal shows> EKI3<screen shows> EKI4<hearing shows>}

EKI1<meter shows >=[:EKI< meter unit >]{EK-kind< meter shape and size visual angle graduation meter layout>, EK-body< visual distance>, EK-producer<the documents of meter design the case of meter design ,the list of meter design >}

EKI2< signal shows >=[:EKI< meter unit >]{EK-kind<signal lamp kinds, signal lamp brightnesssignal lamp color signal lamp appearance >, EK-body< visual distance>, EK-producer< the documents of signal design the case of signal design ,the list of signal design >}

EKI3< screen shows >=[:EKI< meter unit >]{EK-kind< screen size screen location screen observing angle>, EK-body< visual distance >, EK-producer< the documents of screen design the case of screen design ,the list of screen design>}

EKI4<visual communicate>=[:EKI< meter unit >]{EK-kind< frequency sound kinds the number of sound unit>, EK-body< distance >, EK-producer< the documents of visual communicate the case of visual communicate ,the list of visual communicate>}

2.2 Ergonomics Knowledge Carrier modeling

Ergonomics Knowledge Carrier modeling is to describe the carrier form (e.g. documents, figures, forms, and instances) and its existing location. The class of Ergonomics Knowledge Carrier is a cluster of carriers having the same attributes. EKC={EKCi| 1<i<n}. Modeling includes the name of carrier-class, the name of attributes, and the name of its successive father. It is expressed as follows:

<the name of carrier-class> [:<the name of father>] {the cluster of attributes}

Concrete Knowledge Carrier is an instance of the corresponding Class- Knowledge- Carrier. It is good to give concrete value to corresponding attribute. Giving different value to the same model is called classified expression, which

can express the individuality of different classes.

2.3 Ergonomics Knowledge Scenario modeling

Knowledge is of condition. For examples, all design knowledge adopted by the design of knob and working table is not the same. So knowledge scenario modeling is important to communion and re-use of knowledge.

Ergonomics Knowledge Scenario can be shown as EKS{EKDi| 1<i<n},there, EKDi depicts knowledge scenario

from certain point of view. It is called knowledge-dimension. Knowledge scenario is composed of many knowledge dimensions. Each kind of knowledge has given background and condition. As for a kind of Knowledge EKj, its knowledge scenario is expressed as follows:

EKSj {EKD1j EKD2j … EKDn j}, there, EKSj denotes the knowledge scenario of Ekj; EKD1j denotes the value of Ekj in the knowledge-dimension of EKD1, and it may be a value or a cluster. For each value, it may include many species e.g. noun, description, numeral etc.

EKDi {EKDij|1<j<n} there, EKDij is an element of all values in knowledge-dimension EKDi.

3. Computer aided Ergonomics Knowledge management

3.1 Physical Ergonomics parameters database managment

The Physical Ergonomics parameters[9][10] are important data resource of Ergonomics design In this paper, the database is created by means of ACCESS. The anthropometry database includes the adult-body sizes of different percentile , the sizes of standing posture sitting posture plane and ordinary function, the biologic dynamic parameter of anthropometry the height and standard error of different zone and so on. In order to facilitate enquiry, visualization technology is adopted. The parameter interaction and data-exchange have been implemented by dialog interface designed within the system. The system has been designed open for the sake of system maintenance, and different identity users with different right to use the system conveniently.

3.2 Ergonomics Knowledge management

On the basis of the model of Ergonomics knowledge management, Ergonomics knowledge base[1] has been divided to public knowledge base and special knowledge base and created respectively by using ACCESS. It is easy for users to visit correlative design knowledge by keywords. Its logical frame is shown as figure 1.

Figure 1. Logical frame of Ergonomics Knowledge management

3.3 Computer aided Ergonomics design

Ergonomics design is a systems engineering. To realize knowledge reuse and product innovation, a sharing interspace and an innovative interspace have been designed by using VC++. Its flow-frame is shown as figure 2.

The sharing interspace of Ergonomics design is to achieve parametric design, imitative design and innovatory design by the use of the basic functions of knowledge classification, knowledge coding, knowledge indexing and knowledge matching. When the designed-kind perfectly matches that of system knowledge, parametric design is implemented by citing system knowledge entirely. When the designed-kind partly matches that of system knowledge, imitative design is implemented by fuzzy querying and borrowing system knowledge. Innovatory design, none of whose designed-kind is matching system knowledge, is implemented by intelligent querying, matching and referencing system knowledge.

The innovatory interspace is to feedback some new knowledge , cases received and affirmed from imitative design and innovatory design to the sharing interspace so as to enrich ergonomics knowledge base.

The above-mentioned Egonomics parameters play the role of instruction and restriction in product function and other features.

3.4 The integration of Ergonomics design into product design

Product design includes function design and shape design, and function design is premier. Some parameters in accordance with the need of Ergonomics play the role of instruction and restriction in the function design and shape design (sculpt, color, material). So, it is very essential to develop the integrated design system of Engineering design, Ergonomics and industrial design, which facilitates the manipulation and presentation of design ideas effectively and

Ergonomics Knowledge managment

Public knowledge base Special knowledge base

Ratio of

device or

tool to

height

Revising

value of

function

Sensorial

limen of

human-

body

Disply

device

design

Work-

bench

design

Seat

design

EKS EKC EKI

Screen

design

Standard

workbench

design

Seating

posture

workbench

Meter

design .....

standing

posture

workbench

Signal

design

hearing

commu-ni

cation

design

Common

seat design

Working

Seat design

Adjustable

seat design

Special

seat

design

Seating and standing

posture

workbench

Applied

principle of

main Physical

Ergonomics

parameters

..

..

Environnt

design

Safe

design ...

Figure 2. Flow-frame of Ergonomics design

Form 1.

Figure 3. Button design of Engineering Scanner by using CAEKMS

prevents the isolated working practices of product design resulting in design problems being identified only after the design work is complete. In the paper the communicating interface of the CAEKMS and design software (Pro/Engineer, UG) has been designed by VC++6.0. (Not introduced for limited length of the paper). Figure 3 shown the button design

projects of Engineering Scanner in PRO/E, whose Ergonomics Knowledge of button and layout is obtained from the CAEKMS. (e.g. Form 1 only shows knowledge related to button size ).

The finished design of the Engineering Scanner may be saved into the sharing interspace as successful cases making

Work state Button Type Button size(mm) Button distance Button height Button routing

Round 8~18 Single work

Double-work Rectangle 10 10 10 15 15 20

12.5~25mm

( 6mm) 5~12mm 3~6mm

Material design Sculpt design Color design

Product design platform

Pro/Engineer UG..

Function

design

Ergonomicsdesign

Shape

design

Sharing

interspaceInnovatory

interspace

Ergonomics knowledge

management model

YFull matching

Fuzzy matching

No matching

Parametric designAcquiring

knowledge

Acquiring

knowledge

Borrowing

knowledge

Imitative design

Innovatory design

NY

NY

use of the innovatory interspace provided by the CAEKMDS. In this case, the Ergonomics Knowledge Scenario is defined as Engineering Scanner.

4. Conclusion

Ergonomics design is a complex and much coupling design. It demands designers to have all-around Ergonomics knowledge. The Computer Aided Ergonomics Management System (CAEMS) provided in this paper will be an effective design platform. With the help of the CAEKMS, the designers can instruct and restrict product design at any moment and hence avoid the malady to amend repeatedly during the period of evaluating and check, which will improve the design efficiency. At one time, the designers can enrich Ergonomics knowledge base ceaselessly by use of the innovating platform. Therefore, by integrating and establishing the physical Ergonomics parameters database and Ergonomics knowledge base based on the model of Ergonomics knowledge management, it is possible for designers to get physical Ergonomics parameters freely, manage computer aided Ergonomics knowledge intelligently and computer aided product design efficiently.

Acknowledgements: The author is grateful to the members of his research team for their valuable discussions and comments on this manuscript. Thanks also go to my students and my friend for help in arranging this manuscript.

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