Page 38 - trends in automation

An unidentified flying object
floats several metres above
the ground, moving silently
and gracefully. A geometrical
band made from transparent prisms
constantly turns itself inside out. It
contracts, closes to form a compact
shape, then opens and turns itself
inside out. Suspended in and on air,
it pushes off and achieves forward
propulsion through rotation. To the
observer’s eye, it is a fascinating
spectacle, though in his mind he
can’t quite believe what he is looking
at. Until now, the inversion drive only
existed in theory or as a model.
A fascinating discovery
The two classic drive systems are
easy to visualise. A linear drive can be
compared to a cue which moves a
billiard ball in a straight line in one
direction. We use rotary motion when
cycling. The third kind of drive based
on inversion, with its idiosyncratic
sequence of movement, really tests our
powers of perception and reasoning.
It was identified by Swiss artist and
engineer Paul Schatz, who discovered
the geometrical band at the beginning
of the 20th century. What makes it unique
is the “forced movement”, whereby
when one part of the system moves,
the entire system moves with it. Festo
engineers used this basic principle in
the development of SmartInversion.
Freely floating prisms
With SmartInversion, the intelligent
combination of extremely lightweight
design, electric drives and open and
closed loop control makes endless
inversion in the air possible. Movement
is divided into four phases, two of
which generate propulsion. The prisms
are filled with helium so that they can
float freely in the air. Carbon fibre rods
form an ultra light framework, which
is enclosed by a gas tight membrane.
The fascinating shape is set in rotation
by three servo motors, which move the
connecting axes forwards or backwards
depending on the drive phase.
SmartInversion can be controlled
from a smartphone using software
specially developed by Festo.
Four coordinated phases
In order to achieve inversion of the
geometrical band, the three servo
motors are coordinated by an on board
unit. Two of the servos run forwards
and one in reverse, depending on the
motion phase in question. At certain