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Ch29-I044963.fm Page 139 Tuesday, August 1, 2006 3:05 PM
Tuesday, August
1, 2006
3:05 PM
Page 139
Ch29-I044963.fm
139
139
DEVELOPMENT OF A MICRO TACTILE SENSOR UTILIZING
PIEZORESISTORS AND CHARACTERIZATION
OF ITS PERFORMANCE

J. Izutani, Y. Maeda and S. Aoyagi
Systems Management Engineering, Kansai University
3-3-35, Yamate-cho, Suita, Osaka 564-8680, Japan

ABSTRACT
Many types of tactile sensor have been proposed and developed. They are becoming miniaturized and
more precise at the present state. Micro tactile sensors of high performance equal to a human being are
now desired for robot application, in which the skillful and dexterous motion like a human being is
necessaiy. In this research, piezoresistors are made on a diaphragm to detect the distortion of it, which
is caused by a force input to a pillar on the diaphragm. Three components of the force in x, y and z
direction can be simultaneously detected in this sensor. The concept is proposed and its measuring
principle is confirmed by using FEM simulation. Also a practical sensor chip is fabricated by
micromachining process and characterization of its performance is reported.

KEYWORDS

Tactile sensor, Piezoresistor, Microstracture, Micromachining, Gauge factor

INTRODUCTION

An advanced tactile sensor is strongly desired now for the purpose of realizing complicated assembly
tasks of a robot, recognizing objects in the space where vision sensor cannot be used (in the darkness,
etc.), and so on [1, 2]. Besides industry, development of a robot hand will become more important to
realize human-like robots, such as a humanoid. In order to give a tactile sense like human to a robot's
fingertip, development of the tactile sensor with high performance would be required in the near future.
Many tactile sensors have been proposed until now; however, limited by fabrication process a tactile
sensor compatible to human's one has not been achieved yet. On the other hand, micromachining
process based on semiconductor manufacturing process is hot research area and available now. Using
this technology, many tactile sensors are proposed and developed now [3-7J. By this technology many
arrayed sensing elements with uniform performance characteristics can be fabricated on a silicon wafer
with fine resolution of several microns. Authors are also now developing a tactile sensor comprising