Page 433 - Mechatronics for Safety, Security and Dependability in a New Era

Ch84-I044963.fm Page 417 Tuesday, August 1, 2006 5:00 PM
Tuesday, August
Page 417
5:00 PM
1, 2006
Ch84-I044963.fm
417
417
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Figure 2: Structure of search ball with rotating cameras
Because of no locomotion mechanism, 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 and cannot always be located as desired. In
order to cover this weak point, a large number of balls are scattered into rubble; that allows rapid and
wide-area search. It is difficult to search the entire area using only search balls. Hence rescuers or
rescue robots search the remaining area. Such cooperation of search balls and rescuers/robots would
be able to reduce the amount of time required to search inside of rubble.
We suppose to search the inside of a collapsed Japanese-style wooden house; the area to be searched
2
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by search balls at once is less than 100[m ] (10[tn]xl0[m]). Each ball searches 1 [m ] area around
itself. The balls are scattered into the area which rescuers cannot see: for example, beneath or behind
collapsed beams and inclined furniture.
DESIGN OF SEARCH BALL WITH RORATING CAMERAS
Fig.2 illustrates the conceptual design of a search ball with rotating cameras.
Cameras Providing View of Entire Circumstance
Generally, cameras, microphones, infrared sensors and CO2 sensors are said to be effective for
searching inside of rubble for victims. If rescuers check sensor information and judge whether victims
exist, cameras will be most useful sensors. Hence we adopt cameras as the sensors of search balls.
Because balls might be scattered around a victim, they will be able to provide some images of the
victim from different points of view; it is effective for the judgment by the rescuers. In the future, we
will pack other sensors into balls. For example, a microphone permits searching for conscious victims.
A microphone and a speaker enable victims to communicate with rescuers.
Search balls are required to find victims around themselves with their sensors. The locations where the
balls drop cannot be controlled or the balls cannot move after drop, because they have no locomotion
mechanisms: some balls drop into narrow gaps, some balls stop on slopes, and other balls drop to the
bottom. Hence it is desirable that the sensors can look all around the ball. For this requirement, the
proposed search ball rotates cameras using a motor inside for providing the view of its entire
circumstance. As shown in Fig.2, two wireless cameras with 90[deg] angle of view are attached to a
bar with 45[deg] tilted, and this bar is connected to a small motor. Rotating this motor 360[deg]
around, the ball obtains the view of its entire circumstance. Search balls enter inside of rubble, where
it is dark. Hence we attach infrared LEDs around the cameras for illuminating dark environment and
rotate them together with the cameras.
Impact-resistant Ball Structure
Because search balls drop into and repeat collision with rubble, impact-resistant ball structure for
protecting internal parts is required. For this requirement, the motor connected to the cameras and