Page 60 - Mechatronics for Safety Security and Dependability in a New Era

Ch10-I044963.fm Page 43 Tuesday, August 1, 2006 8:42 PM
1, 2006
Tuesday, August
Page 43
8:42 PM
Ch10-I044963.fm
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DYNAMIC MODELING FOR ATTENDANT
PROPELLING WHEELCHAIRS
2
Tatsuto Suzuki' , Hironobu Uchiyama and Junichi Kurata 2
Department of Mechanical Engineering, Maizuru National College of Technology,
Maizuru, Kyoto 625-8511, JAPAN
2
Department of Mechanical Engineering, Kansai University
Suita, Osaka 564-8680, JAPAN

ABSTRACT
The purpose of this study is to establish the model of attendant propelling tasks in order to design for
safe and low load attendant's propelled wheelchair with assist system. We propose the model of
attendants with assumption that attendant and wheelchair is basic motor-load system. The validation of
the proposed model identified by experiments shows well corresponding to real attendant's propelling
behaviour. From the results, the proposed model is used effectively for safe and low load design of
assisted wheelchairs.

KEYWORDS

Attendant propelling wheelchair, Assist system, Attendant's model, Safe and low load design

INTRODUCTION

Attendant's propelled manual wheelchairs provide the opportunities of social activities for those who
cannot propel wheelchairs themselves. But it's hard for attendants to propel wheelchairs with the
people to move place to place with keeping safe against around traffic. So attendants strongly desire
the wheelchair easy to propel and stop. Cremers (1989) developed the attendant's propelled
wheelchairs with assist system for reducing the attendant's loads and now some type of them are
commercialized. The recent wheelchairs with assist system have motorized wheels driven by the
controller which detects propelling force of grips and continuously determines amount of assisting
force exerted by the motorized wheels. Recently, attendants want high assist force because our society
becoming aged and low birth rate brings deficit of young attendants, so attendants become aged
gradually. Rising assist force causes rapid and unstable wheelchair's movement, because small
changes of propelling force provide large torque of auxiliary wheels by the controller. In addition, it's
easy to expect that various uneven surfaces, such as thresholds, openings, gaps, cracks and holes on
road dynamically change the propelling force of wheelchairs. Therefore, it's difficult for attendants to