Several military branches require certain equipment and supplies to be airdropped strategically and covertly, as well as more accurately than usual. Members of the U.S. Army’s Joint Precision Airdrop System (JPADS) program worked with Atair Aerospace (NY) engineers to develop a new autonomous guided parachute called the “Onyx” that geographically targets and places these loads.
Onyx is a family of fielded, commercial off-the-shelf systems that deliver payloads ranging from zero to 2200 lbs with a variety of unmanned aerial vehicles (UAVs). Maxon Precision Motors, (Fall River, Mass.) makes and modifies the motors and planetary gearheads that control each Onyx unit’s guidance system.
The Onyx units safely and precisely deliver sensitive or essential cargo to difficult-to-reach or dangerous locations. Each system is launched from C-130 or C-17 aircraft. The cargo is
deployed at 35,000 ft and at speeds to 150 Knots Indicated Air Speed (KIAS). The systems glide over 44 km and land cargo within 100 m of their selected targets, aiding rapidly moving ground and special operations forces, as well as precisely placing unattended ground sensors and small munitions.
The Onyx unit consists of a two-parachute hybrid device. One part of the device uses a high-efficiency ram-air elliptical parafoil for self-directed guidance. The second part is a round recovery parachute that ensures a soft landing for sensitive cargo. A proprietary on-board guidance, navigation, and control system uses an integrated GPS and inertial navigation to continually adjust flight characteristics and adapt to the weather conditions throughout the flight, controlling the system to a pre-programmed altitude and position. The second, non-guided round recovery parachute opens prior to landing for a soft touchdown at its programmed point of impact.
Onyx parachute systems were developed to safely and precisely deliver sensitive or essential cargo to difficult-to-reach or dangerous locations.
Real-time collision avoidance and flight algorithms that govern swarming and flocking flight behavior enable operators to deploy multiple Onyx units in the same air space without risk of midair collision. The adaptive control makes it possible for the units to fly correctly under adverse conditions; such as gross variances in wing loading and asymmetrically-rigged payloads from pre-flight rigging errors or cargo changes. The control also corrects for damage induced while in flight. Each system controller operates independently, eliminating supervisory control.
Specially modified motors and planetary gearheads from Maxon Precision Motors control Onyx guided parachute payload delivery systems in military applications. One motor-gearhead combination adjusts the right side steering winch of the parachute while the other combination maneuvers the left side.
A controller interfaces with two steering winches attached to the parafoil to control flight patterns. The winches either draw in or pay out the parachute similar to that of the ailerons of an aircraft. One motor-gearhead combination adjusts the right side of the parachute while the other combination maneuvers the left side.
“Customization was necessary for our use,” says Daniel Preston, CEO & CTO of Atair Aerospace. “These custom motors were modified from commercial off-the-shelf units so they could be used at up to six times their rated output power.” The custom specifications include special lubricants for high altitudes, and for full mil spec temperature ranges from -50 to +85 C. Motor components that are typically press-fit had to be laser welded. “The motors needed to handle shock and vibration beyond what a typical motor would see,” Daniel says.
Even the planetary gearheads were altered with special non-standard materials for additional strength. Different alloys and different heat treatments were used in the internal components of each gearhead. Although all custom work was initially completed by Maxon Motor at its factory, Atair has duplicated some of the special tooling to handle the work in-house.
Key Features of Onyx Systems
• Available in three payload configurations: Micro Onyx (0 to 20 lbs), Onyx 500 (0 to 500 lbs), and Onyx 2200 (500 to 2200 lbs)
• Accuracy of 100 m
• Two-parachute (“hybrid”) system that uses a high-speed elliptical parafoil for autonomous guidance and a round recovery parachute for a reliable soft landing
• Flocking/Swarming (formation flying) and active in-air Collision Avoidance for simultaneous deployment of up to 50 Onyx systems
• Adaptive Control, an advanced self-learning method for flight control, enables gross variances in cargo weights to be airdropped
• High glide ratio over 4.5:1 for a horizontal standoff of 44 km from an altitude of 35,000 ft
• Deployable from military fixed-wing and rotary aircraft up to 150 KIAS
• Fast flight speed (80 knots true speed) increases accuracy and reduces vulnerability to wind- induced errors and detection
• Continuously dis-reefed guidance parafoil for lowest opening shock and high speed deployment
Maxon Precision Motors
: Design World :
Filed Under: Motion control • motor controls
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