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Intelligent Control of
UAVs
Abstract:
Uninhabited Air Vehicles (UAVs) and Uninhabited
Combat Air Vehicles (UCAVs) operate in environments with a
high likelihood of damage and hardware failure, thus removing
life-threatening situations for pilots. BAI is designing the
intelligent controls that retain a high level of sophistication
and performance and minimize development costs.
Problem:
Lowering
production costs on UAVs and UCAVs might include removing
non-flight-critical systems such as countermeasures and highly-redundant
actuation. There is also a strong requirement to reduce the
autopilot development costs for these vehicles. UAVs will
have to make up for their lack of sophistication in hardware
with more complex software, and in particular control software.
The need for intelligent control of UAVs / UCAVs becomes evident.
Intelligent control algorithms are expected
to provide: autonomous trajectory generation given waypoints
or high level tasks, control reconfiguration for command tracking
despite damage and control effector failures and learning
mechanisms by which the controller compensates for mis-modeled
or changed vehicle dynamics online.
Solution:
BAI has assembled a team who collectively
have decades of experience in the development, implementation
and flight testing of both production controller and advanced
research flight control systems. The key technical features
of the team's algorithms are:
- Learning: the stability and control loops
use function approximators with local support, which learn
the stability and control derivatives of the aircraft as
it flies. This is a significant advantage over other adaptive
control methods which do not retain useful (or any) information
about the aircraft.
- Online trajectory generation: a hybrid automaton
generates trajectories for way point (along with velocity,
flight path, and heading) following. The initial libraries
used by the automaton are constructed off-line, but mechanisms
for on-line modification of the databases are included to
reconfigure the trajectory generator as necessary.
- Reconfiguration: provided both in the control
algorithms and the trajectory generation.
- Provable Stability: development of both components
of the intelligent controller are based on formal
stability analysis.
- Reduced Development Cost: the control design
is first performed in a low-cost, medium-fidelity simulation,
but is still applicable to the true air vehicle. This technique
is validated by applying the control laws to a high-fidelity
simulation of a UAV.

REFERENCES
1.
Ward, D.G., J.F. Monaco, and J.D. Schierman, "Reconfigurable
Control for VTOL UAV Shipboard Landing," Proc. AIAA Guidance,
Navigation, and Control Conf., Portland, OR, Aug. 1999, AIAA
Paper No. 99-4045. |