A "magic table" which can rearrange objects without
touching them has been developed in California. The invention could
soon lead to tables that set themselves, bar tops which deliver
their own drinks and better automated industrial processes.
Dan Reznik's unique 'Universal Planar Manipulator'
moves an object placed on its surface without affecting other
objects using nothing more than vibrations.
And the UPM is not very noisy, says Reznik, a
graduate student at the University of California in Berkeley,
California. "There's no up and down movement, otherwise it would
make the surface act like a speaker."
The surface vibrates horizontally thanks to four
vertical, flexible supports. These are like table legs with motors
attached. The frequencies applied to the surface are fairly low so
the vibration is not very noticeable, says Reznik. At the very most
it would feel like a massage device.
Precise movement
Very selective and precise movement is produced by
superimposing three frequencies. "A single horizontal surface is
capable of moving an individual object while keeping the other
objects on the surface still," he says.
Two frequencies of 35 and 70 Hertz produce a
conveyor belt effect, "like an inchworm," says Reznik. A third
frequency of 29 Hertz creates rotational motion like a pivot.
By varying the phases of the three it is possible
to control very precisely how different parts of the plate affects
objects on its surface. A null frequency can be achieved where no
motion occurs.
"So, perhaps your desk is a little messy and you
want to tidy it up," says Reznik. At the press of a button the desk
moves your clutter to its usual place using nothing more than the
vibrations of the desktop.
He also envisages self-setting tables but it will
have to be dinner for two. According to Reznik the number of objects
it can manipulate simultaneously is limited. So far he has managed
to control eight objects independently at the same time, but he
thinks more than ten would be difficult.
The UPM is one part of the Distributed Manipulation
project at Berkeley. Other ways of moving objects across surfaces
which are being investigated include arrays of tiny hairs, rollers,
electron magnets and even air nozzles.
Correspondence about this story should be directed
to mailto:latestnews@newscientist.com?subject=Shaky
legs
1429 GMT, 5 October 2000
