Utilization of D-Six for AFRL UAV Automated Aerial Refueling
The
Air Force Research Laboratory is investigating automated aerial refueling
for Unmanned Air Vehicles (UAV) in order to extend the utility of these
configurations. Because the primary operational limitation of an unmanned
vehicle is the volume of onboard fuel, and the most critical flight
phases for a UAV are the launch and recovery, this capability is highly
desirable for UAV operations. Such a capability will make these vehicles
more effective by extending UAV’s ferry ranges, and significantly
improving vehicle 
mission
range and time-on-station. However, the operation of an unmanned vehicle
in a precision flight control mode at such close proximity to a manned
tanker is a considerable technical challenge. Further, many of the current
and evolving UAV vehicles have limited maneuverability because of restricted
operational requirements and for stealth reasons, further complicating
vehicle control in the turbulent tanker wake. In order to assess a vehicle’s
control capabilities and develop robust automated refueling controls
and strategies, a high fidelity model of the vehicle and it’s aerodynamic
characteristics in the wake of a tanker aircraft are needed. These models
must be assessed in a simulation environment that allows the close coupling
of the parent and receiver models with the mutual aerodynamic interactions.
In
order to develop the UAV refueling capability, the development of a
number of technologies were required. The acquisition of the vehicle
interactions was critical in order to establish the remaining technical
goals. Bihrle Applied Research (Bihrle), under SBIR Phase II funding from
the Air Force, recently developed a new testing capability using the
Langley Full Scale Tunnel to collect wind tunnel test data on multiple
models concurrently while accurately positioning the models in the x,
y, and z axes. The development of this test technique resulted in the
successful acquisition of multi-vehicle test data as a function of position.
While no tanker UAV combinations were examined in the initial effort,
the scaling of some of the UAV test data was proposed for the demonstration
of the simulation capability and control algorithm development.
For
the initial effort, a preliminary close-formation control logic for
the UAV was designed and implemented on an engineering F-16 flight model
hosted in Bihrle’s D-Six simulation environment. Formation-induced
aerodynamics effects acquired from previous wind tunnel tests for F-18’s
and USAF Innovative Control Effector (ICE) UAV configuration were scaled
to the baseline F-16 aerodynamics model. This evaluation provided the
opportunity to examine the projected UAV’s aerodynamic control
authority required to maintain position and to maneuver in close-formation
near the tanker. Successful station keeping and around-the- tanker maneuverability
was demonstrated using the refueling control algorithm, although the
control power available in this preliminary assessment was not necessarily
representative of a current UAV.
Other D-Six Success Stories
Implementation of Wright Laboratory
F-16 MATV Simulation into D-Six
Application
of D-Six at Air Force Research Laboratory
Italian
AV-8B II+ Mission Simulator Aerodynamics Model Development
Fokker
Control Loading and Motion
Boeing
F-18 E/F Flight Control System Test Station
Utilization
of D-Six for ACAS Development
Pilatus
Aircraft Engineering Flight Simulator
Boeing
F-18 E/F Flight Control System Test Station
