Page 39 - Mechatronics for Safety, Security and Dependability in a New Era

Ch06-I044963.fm Page 23 Tuesday, July 25, 2006 11:50 AM
Tuesday, July 25,2006
Page 23
11:50 AM
Ch06-I044963.fm
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DEVELOPMENT OF A MOBILITY AID
FOR THE VISUALLY IMPAIRED
USING A HAPTIC FORCE GENERATOR

1 2
1
1
T. Ikeda ' , H. Matsuda , Y. Shiota , K. Sakamoto 2 and Y. Shimizu 2
1
Department of Rehabilitation Engineering, Polytechnic University
2
Systems Engineering, University of Electro-Communications

ABSTRACT
This paper describes the development of a "virtual cane," a kind of walking aid for the visually
impaired, using a liaptic force generator consisting of a gyroscope and its controller. It is shown
theoretically that the liaptic force generator can change the superficial moment of inertia of a
rod. Good agreement between the analytical and experimental results indicates that the haptic
force generator provides one of the essential functions of the virtual cane.

KEYWORDS
virtual cane, visually impaired, haptic illusion, gyroscope, liaptic force generator

INTRODUCTION

The white cane is currently used by the visually impaired as a mobility aid. Visually impaired
individuals often face difficulty in using the white cane in places such as supermarkets, where
products or other people often present barriers to free movement. Several mobility aids have been
developed in order to overcome this problem(Funakubo and Hatsuyama, 1995). Such devices
detect obstacles by means of infrared rays or ultrasonic waves and indicate the presence of
obstacles by vibration. Although these devices are useful, thorough training is required to become
skilled in the use of such devices. If a device reproduces the inner force sense to the same degree
as would be perceived using a white cane, then the user can visibly perceive the existence of
obstacles without contacting them. We herein refer to such a device as a "virtual cane."'
The main component of the virtual cane is a haptic force generator. This paper focuses on a
haptic generator using a gyroscope. It is shown theoretically that the haptic force generator can