Attitude Control Enhancement Using Wing Load Sensing

ABSTRACT: As Small Air Vehicles (SUAVs) transition into theater with ever-increasing capabilities, the necessity for tailored avionics becomes acute. The Air Force and OSD emphasize an increasing role for SUAVs and providing squad-level units with ever-more capable, man-packable air assets. These smarter and smaller UAVs will perform complex including below roofline urban ISR and precision strike. Conventional fixed-wing vehicles with IMU-based control laws do not meet the performance required to operate in these environments; bio-inspired approaches to sensing, control, and actuation will need to be incorporated. Proprioception, a technique to react to environmental disturbances reflexively using torque feedback, is under investigation by Aurora and AFRL through the use of torque error to control actuator position and the use of body force sensing to compensate for high optical/outer-loop sensor feedback latency. Extending the approach to all three rotational axes and by applying the concept in a more distributed fashion, along the wing for example, provides even more improvement. Coupling this with bio-inspired vehicle concepts such as distributed actuation yields an exceptionally capable vehicle. Aurora will work with the University of Maryland to analyze available COTS and other cutting edge sensors to extend the concept of proprioceptive sensing to its performance ceiling. BENEFIT: The PWings system provides three potential productization paths (1) as a self-contained package, installed as an after-market modification, (2) as a system to be included in the build-up/development of new systems, and (3) as a fully functional, high performing aircraft produced and sold by Aurora. PWings is attractive to any customer seeking controllable flight in gustier conditions, greater maneuverability, and lifetime wing load monitoring and gust-load alleviation. The PWings system will be developed initially for micro- and small- UAV military applications but the benefits and applications are relevant for all classes of UAVs. As developed in Phase II, the base system will provide enhanced stability, a larger flight envelope, and greater maneuverability to the SUAVs conducting SUAV-related missions, viz. urban ISR and lethal engagement. Ideal platforms would be smaller UAVs with severe weight and volumetric limitations, those not capable of carrying gimbaled payloads for example. SUAVs tend to be more affected by turbulence and wind speeds rendering onboard video above 20 knots useless and flight infeasible in wind speeds over 25 knots. Mechanically stabilized video or even on-board digitally stabilized video greatly improves the military utility of ISR missions but as UAVs continue to decrease in size to support the squad and single soldier CONOPs, integrating these payloads will be infeasible. PWings will provide platforms such as the Aerovironment Raven and Wasp with an alternative stabilization method with a much smaller weight footprint. In addition, PWings would increase the wind ceiling for SUAVs over the typical limit of 20 knots allowing these assets to be used much more often. With over 13,000 Aerovironment Raven SUAVs built to-date , a per system cost of $250k, and a projected UAV sales of $1.8 billion over the next 10 years for"mini"and small tactical UAVs , SUAV enhancements is a lucrative market. During fiscal 2011, the U.S. Army, the largest Raven user, increased its projected total demand for our Raven small UAS by 8%, from 2,182 to 2,358 new systems. One can look to the Raven DDL block upgrades as a model for the market potential of Program of Record system upgrades like PWings. The Raven DDL retrofit kit was completed in fiscal year (fy) 2010 contributing to a UAS service revenue of $20.9 million in fy 2011, and increase in total UAS revenue of $13 million for a total of $224 million of fy 2011.