Army matures autonomous flight technologies

The K-MAX helicopter performs autonomous operations at a Fort Benning, Georgia test. (U.S. Army photo)

The K-MAX helicopter performs autonomous operations at a Fort Benning, Georgia test. (U.S. Army photo)

By Ryan Keith, AMRDEC Public Affairs

Virtually all aircraft, from the Wright brothers first airplane at Kitty Hawk, North Carolina, to the unmanned aircraft systems employed in operations today, share a common component: Pilots. Whether in the cockpit or through remote control, pilots have remained a critical component to aviation, until now.

Researchers at the Aviation and Missile Research Development and Engineering Center at Redstone, Alabama, are developing and demonstrating autonomous flight technologies that promise to change the future of aviation.

TERRAIN-AWARE AUTONOMY

“With any helicopter, the strength of that platform is the ability to hover and operate in close proximity to the ground or obstacles,” said Matt Whalley, Autonomous Rotorcraft project lead at AMRDEC’s Aviation Development Directorate – Aeroflightdynamics Directorate. “To do that autonomously requires some new technologies — terrain sensors, navigation algorithms and programs that can look at the ground and find the safe landing spot.

Whalley said his group has been focused on that challenge for several years.

“We’re trying to bolster those core technologies that would enable new types of operations or expanded operations with autonomous helicopters,” he said.

The team developed a comprehensive small- and full-scale autonomous helicopter research capability using unique in-house skills in helicopter guidance and flight control, robotics planning and scheduling and emerging unmanned aircraft sensor technology.

Researchers validated software algorithms and further developed it into commercial software libraries, which led to distribution under a technology transfer agreement.

Whalley and his team demonstrated the scalability of the technologies and software by migrating the algorithms to AMRDEC’s full-authority JUH-60A Black Hawk helicopter for flight testing.

In 2012, AMRDEC personnel successfully demonstrated low-level autonomous behaviors critical to the next generation of unmanned military rotorcraft. These behaviors include obstacle field navigation in complex and cluttered terrain and safe landing area determination.

“This was the first time terrain-aware autonomy has been achieved on a Black Hawk,” said Lt. Col. Carl Ott, chief of the Flight Projects Office at ADD-AFDD.

Engineers conducted testing on the Rotorcraft Aircrew Systems Concept Airborne Laboratory, or RASCAL, a JUH-60A Black Hawk equipped with the H.N. Burns 3D-LZ laser detection and ranging system for terrain sensing.

“The RASCAL aircraft was the ideal platform to demonstrate this technology,” said Jay Fletcher, RASCAL project manager. “It provides a fully programmable, fly-by-wire flight control system and [has] advanced sensor interfaces for rapid prototyping of new concepts while maintaining the standard UH-60 hydro-mechanical flight control system as a safety backup.”

Additional tests followed, demonstrating key maneuvers, obstacles and other events that human pilots encounter and react to during flight, including avoid high-power lines and other aircraft, selecting a landing area and exiting from a box canyon.

The American Helicopter Society awarded its 2013 Alfred Gessow Award for a paper describing this effort, and Whalley received the RDA Outstanding Technical Leadership Award for guiding the government-contractor team.

ADD director Dr. Bill Lewis said the awards are a satisfying acknowledgement of a decade of cutting-edge autonomy research by AMRDEC engineers.

“The ARP team has led the world in developing Obstacle Field Navigation and Safe Landing Area Determination technology for rotorcraft,” Lewis said. “Flight tests on AMRDEC RASCAL JUH-60 have conclusively demonstrated mission level benefits of these technologies for Army rotorcraft and pave the way for future implementation on production aircraft.”

UAS AUTONOMY

Through a Joint Capability Technology Demonstration sponsored by the Office of the Secretary of Defense, AMRDEC is integrating, flight testing and demonstrating improved autonomy products on the unmanned K-MAX power lift helicopter.

The Autonomous Technologies for Unmanned Aerial Systems JCTD addresses a requirement identified by the U.S. Central Command for a cargo unmanned aircraft system that can quickly, safely and accurately deliver mission critical and time sensitive resupply to Soldiers on the ground.

Sara Condon, the ATUAS JCTD technical lead at the ADD – Aviation Applied Technology Directorate, said that high threat environments and difficult terrain present numerous challenges for resupply.

“Unimproved roads and inhospitable terrain force ground convoys to carry smaller, lighter loads and travel at slower speeds,” Condon said. “This lack of speed and predictable routes make movements susceptible to improvised explosive device attacks.”

While utility and cargo helicopters address many of these concerns, Condon said the limited number of these kinds of vehicles forces commanders to choose between conducting logistical resupply missions or operational support missions. Also, resupply operations in extreme heat and high altitudes reduce the cargo carrying capacity of the aircraft resulting in the need for additional sorties to meet Soldiers’ resupply needs.

The ATUAS has the capability to fly multiple-load in-stride cargo delivery missions or single location retrograde missions, when properly configured, while continually providing situational awareness feedback to a ground control station operator.

“During delivery operations, the aircraft autonomously identifies obstacles, selects safe drop-off locations, avoids obstacles, drops off loads and departs,” Condon said. “During retrograde operations the aircraft autonomously locates the retrograde load, identifies and avoids obstacles, maneuvers over the load, connects to the load and departs.”

The aircraft uses GPS to guide it in the general cargo delivery area. When the UAS is within 300 meters of the target, a beacon provides flight guidance to the flight control computer. As the aircraft maneuvers within the field of view of the camera, more precise guidance is provided to the aircraft as to the exact cargo drop-off location.

AMRDEC senior aerospace engineer Mohammadreza Mansur said the greatest challenge was developing the system for the high-altitude, high-turbulence and high-wind environments that the helicopter would face in Afghanistan. He developed and validated an extensive simulation-modeling suite and was responsible for the analysis and optimization of a complex core flight control system.

“Even though the aircraft is flying autonomously, a pilot was on board [during flight tests] to control the aircraft if the control laws were not doing what they were supposed to do. Their comments were: ‘The aircraft flies the way I would.’ It’s the best comment you can get from a flight-test pilot,” he said.

Mansur received an RDA Outstanding Achievement Award for the design and flight test development of flight control laws for the unmanned K-MAX helicopter.

During Mansur’s two years of work, the project emerged from a developmental program, to demonstration flight tests and deployment. In December 2011, K-MAX became the first unmanned aerial system to deliver cargo in-theater for the U.S. Marine Corps. Two aircraft deployed for a six-month demonstration period that was extended to two and a half years.

Capt. Patrick Smith, the U.S. Navy’s Cargo UAS program manager, praised the performance of the aircraft during a July 2014 teleconference with reporters. “[They] excelled beyond anything I thought possible,” he said.

Lewis said the AMRDEC teams are happy and excited to have been critical to the unprecedented operational success of the unmanned K-MAX in Operation Enduring Freedom.

“Working closely with Lockheed Martin and Kaman Aerospace, ADD-AFDD developed the flight control software at the heart of the unmanned K-MAX,” Lewis said. “Receipt of the 2012 RDA Award acknowledges not only the high quality of this outstanding technical achievement, but the potential for aviation S&T to directly benefit the warfighter.”

Meanwhile, the ATUAS JCTD continued to develop, integrate and demonstrate added autonomous capabilities. In fiscal 2012, the team demonstrated, certified, and transitioned the beacon system for the Marine Corps Cargo Unmanned Aerial System deployment. The team initiated integration of autonomous delivery beyond line of sight, autonomous enroute re-programming, in-stride multiple drop locations and control of two vehicles for a single ground control station.

During the second technical demonstration in 2013, the team demonstrated an enhanced electro-optical infrared capability for operator situational awareness, obstacle avoidance, safe sling-load delivery area determination, dynamic route re-planning and other capabilities.

The ATUAS Program Office is planning additional follow-on efforts, including further experimenting with multi-vehicle control and mission planning.

In August 2014, Lockheed Martin and the Tank Automotive Research, Development and Engineering Center successfully conducted a fully autonomous resupply, reconnaissance, surveillance and target-acquisition demonstration using TARDEC’s Squad Mission Support System unmanned ground vehicle, K-MAX unmanned helicopter and Gyrocam optical sensor. During the a capability assessment to extend the reach of the warfighter through robotics, K-MAX delivered SMSS by sling load to conduct an autonomous resupply mission scenario for Soldiers defending a village robotics at Fort Benning, Georgia.

FUTURE VERTICAL LIFT

The Future Vertical Lift initiative will develop the next generation of vertical lift aircraft for the joint warfighter. FVL has three main tenets: to improve aircraft performance, survivability, and to significantly reduce operating costs.

Aircraft must be able to fly farther and faster, carry heavier payloads, be easier and less expensive to sustain, team with unmanned systems, and perform certain optionally-piloted missions.

“AMRDEC is currently leading the development of the Future Vertical Lift family of aircraft, all of which are required to be either optionally piloted or fly autonomously,” Lewis said. “This once impossible task is now just the next step.”

The history of military aviation is highlighted by the exploits of great pilots. Lewis, himself a retired Army aviator, envisions a future where pilots manage aircraft and the systems contained therein as autonomous technologies continue to evolve.

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The Aviation and Missile Research, Development and Engineering Center is part of the U.S. Army Research, Development and Engineering Command, which has the mission to develop technology and engineering solutions for America’s Soldiers.

RDECOM is a major subordinate command of the U.S. Army Materiel Command. AMC is the Army’s premier provider of materiel readiness–technology, acquisition support, materiel development, logistics power projection and sustainment–to the total force, across the spectrum of joint military operations. If a Soldier shoots it, drives it, flies it, wears it, eats it or communicates with it, AMC provides it.