Orbital Research Wing Flutter Control - Manual

Transportation
rbital Research Inc. of Cleveland, Ohio has
developed a software program that “thinks”
change. By way of Small Business Innovation
Research (SBIR) contracts from Langley Research
Center, an Orbital Research Intelligent Control Algo-
rithm
™ (ORICA ™ , rhymes with “eureka”) has been
developed. It is the first practical hardware-independent
adaptive and predictive control structure, specifically
suited for optimal control of complex, time-varying
systems.
Orbital Research has applied ORICA technology to
the problem of controlling aircraft wing flutter, move-
ment that is akin to a shimmy in an automobile. The
effectiveness of the control software has been validated
during wind tunnel testing at Langley. In related work,
Orbital Research and NASA’s Lewis Research Center
have determined that the company’s controller could be
coupled with Lewis’ high speed valve technology to
improve aircraft performance.
The company’s technology, coupled with NASA
expertise, has the possibility of making jet travel safer,
more cost effective by extending distance range, and
lowering overall aircraft operating costs.
There are three main components to ORICA. At its
heart is an Identifier Module which estimates a math-
ematical model of the system that is being controlled.
The model, which is re-identified at every time step,
relates the effect of each actuator input to the output of
the system. The mathematical model estimated by the
Identifier Module is then used by the Predictor Module
to predict the future condition of the system to be
controlled. Finally, the Controller Module uses the
estimated future response of the system developed by the
Predictor to calculate the actuator’s optimal position to
meet the desired response.
To a pilot, large changes in control before action
takes place, could mean the difference between life and
death. The ORICA controller doesn’t wait to take
action. Rather, the intelligent software program antici-
pates and makes adjustments beforehand. As shown in
Langley wind tunnel testing, the ORICA can control a
small flap on a wing, nullifying flutter by regulating the
flap’s angle as many as 500 times per second.
Because of its computational efficiency, the superior
performance of ORICA was achieved by employing a
personal computer platform (Intel
® Pentium ® ) as
opposed to more expensive hardware commonly tasked
for these high speed flutter suppression tests. ORICA’s
special algorithms require only one percent of the
computations of other more expensive and complex
academic controllers.
One of ORICA’s first applications was in suppres-
sion of flutter of a wing subjected to speeds up to Mach
0.95 at Langley’s Transonic Dynamics Tunnel. ORICA
successfully reduced vibrations on the wing by an order
of magnitude over a standard fixed gain controller.
The commercially available ORICA software is not
strictly for use on aircraft. Future application areas for
ORICA include control of robots, power trains, systems
with arrays of sensors, or regulating chemical plants or
electrical power plant control.
™ Orbital Research Intelligent Control Algorithm and
ORICA are trademarks of Orbital Research Inc.
® Intel and Pentium are registered trademarks of Intel Corporation.
Wing Flutter Control
Wind tunnel testing of ORICA
intelligent control software has
shown it to be highly responsive in
damping out wing flutter.
Application to commercial aircraft
could result in safer and more cost-
effective jet travel.
O
1997 NASA
Spin-offs Article