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Ch17-I044963.fm Page 77 Monday, August 7, 2006 12:42 PM
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SPREADING OF CLOTHES BY ROBOT ARMS
USING TRACING METHOD

Khairul Salleh, Hiroaki Seki, Yoshitsugu Kamiya and Masatoshi Hikizu

Department of Mechanical Systems Engineering, Kanazawa University,
Kakuma-machi, Kanazawa, Ishikawa, 920-1192 JAPAN

ABSTRACT
This paper proposes a method of clothes spreading using two robot arms with sensors equipped
grippers and a fixed CCD camera. This research is focused on getting the robot arms to find and hold
two side-by-side corners of a rectangular towel, one by using a simple image processing method and
the other by using a unique tracing method. The tracing method in our context is a method of tracing
the towel's edge by a robot arm based on the feedbacks from sensors and also images from the CCD
camera. By using this method, we have succeeded in spreading a rectangular shaped towel.

KEYWORDS
Edge tracing, deformable object, edge of clothes, corner, image processing, home service robot

INTRODUCTION

Unlike factory robots that do routine work and mostly handle rigid objects, home service robots must
be able to cope with changes to the surroundings and be able to manipulate soft objects. Unfortunately,
the development of robots that can accomplish complicated housework that requires complicated
manipulation is difficult and is still in the early stages although urgently required. We focused on this
problem and chose clothes spreading and folding as an example. In daily life, spreading clothes is an
action conducted usually before hanging one's clothes to dry or folding it. The reason why clothes are
hard to manipulate is because they are deformable objects. There are several theoretical researches
[ IPI
concerning clothes manipulation but very few have been proven practically ' . We decided then to do
a practical research using our own suggested method. The basic idea of clothes spreading is to hold the
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corner(s) of the clothes in order to spread or fold it' . The problem is how to find the corner(s). A lot of
past researches failed because of this. Although the usage of CCD camera plays a big role in finding a
corner [2im , the corner(s) of clothes will not necessarily be visible to the camera. This will result in the
robot not holding the true corner of the clothes thus resulting in improper handling of the clothes. By
using tracing method to find the second corner, we will prove that the second corner found is the one
next to the corner initially founded and not the one across it.