Page 432 - Mechatronics for Safety, Security and Dependability in a New Era

Ch84-I044963.fm Page 416 Tuesday, August 1, 2006 5:00 PM
Ch84-I044963.fm
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416 Page 416 Tuesday, August 1, 2006 5:00 PM

sensor data
monitoring computer

Figure 1: Concept of search ball

Takamori (2003), Tsukagoshi (2002, 2004), Wolf (2003)). But they are large, heavy, expensive and
high energy consuming because they have locomotion mechanisms. In addition, they require operation
skill. Accordingly, rapid and wide-area search may be difficult using only these robots.
For these problems, we have proposed a concept of "search ball" for searching inside of rubble (Inoue
(2005)). A search ball is a small sensor unit which is not equipped with locomotion mechanism but
contains some sensors for searching for disaster victims, such as cameras, and a radio transceiver in an
impact-resistant outer shell. Many balls are thrown into rubble and fall down while repeatedly
colliding; they are scattered inside the rubble. Each ball searches the surrounding area with its own
sensors. The sensor information from the balls is transmitted on radio out of the rubble and monitored
at a safe area. In this way, rescuers can search a wide area inside the rubble rapidly. When the rescuers
are removing the rubble to rescue the found victims, the balls are collected for reuse. Search balls can
be made small so as to enter narrow space among rubble and have the merits of lightweight, low
energy consuming and easy operation. The problem of search balls is that they cannot move actively.
In order to cover this weak point, a large number of balls are scattered into rubble.
In the present paper, a new type of search ball is developed: it contains two wireless cameras for
search, infrared LEDs for illumination, a radio receiver for communication with outside monitoring
computers and a battery. This ball can provide the view of its entire circumstance by rotating the
cameras using a motor. Its sphere outer shell is made of impact-resistant and transparent plastic, thus
protecting these internal parts from drop impact and collision with rubble. Just like a brim of a hat, a
ring is attached to the shell for suppressing rolling of the ball; it is effective for distribution of balls
inside rubble. The outside computer identifies the balls inside rubble and acquires the sensor
information from them by one-to-one communication.
CONCEPT OF SEARCH BALL

Search balls are rescue devices to search for disaster victims buried under rubble. A search ball is not
equipped with locomotion mechanism but contains some sensors and a radio transceiver in an
impact-resistant outer shell. Fig.l shows the process of searching inside of rubble using search balls.
1) Rescuers throw many balls into rubble. The balls fall down while repeatedly colliding with the
rubble, and they are scattered inside the rubble.
2) Each ball searches the surrounding area with its own sensors, and the sensor information is
transmitted on radio out of the rubble.
3) The rescuers outside the rubble check the sensor information from all balls and find victims.
4) With the aid of the signals from the balls which detect the victims, the rescuers get gradually close
to the victims while removing the rubble.
5) In process of removing the rubble, the rescuers collect the balls for reuse.