Precision Motors Help Guided Parachutes Deliver Cargo
- Saturday, 01 December 2007
The Onyx guided parachute designed and manufactured by Atair Aerospace (Brooklyn, NY) is an autonomous precision airdrop system. The unmanned aerial vehicle (UAV) uses motors and planetary gearheads manufactured by Maxon Precision Motor (Fall River, MA) to drive the parachute’s mechanical mechanisms.
Onyx fulfills the precision airdrop requirements under the U.S. Army’s Joint Precision Airdrop System (JPADS) program, developed to transition the U.S. military’s WWII-era low-altitude, low-accuracy, high-vulnerability airdrop practices into the 21st Century. The fielded, commercial off-the-shelf systems can deliver payloads ranging from 0 pounds to 2,200 pounds, through the use of various-sized UAVs.
The Onyx parachutes can be likened to smart bombs, but are used for the safe, precision delivery of sensitive or essential cargo to difficult-to-reach or dangerous locations. Each system is deployed from the air using military fixed-wing and/or rotary aircraft, such as a C-130 or C-17. Deployment can happen at altitudes up to 35,000 feet and at speeds up to 150 KIAS. The systems autonomously glide over 44 km and land cargo within 100 m of its selected target. Onyx systems give military planners the capability to strategically and covertly position equipment and supplies for rapidly moving ground and special operations forces. Onyx systems can also be used for the precision deployment of unattended ground sensors and small munitions deployed from military aircraft and UAVs.
A patented, two-parachute hybrid, Onyx uses a high-efficiency, ram-air elliptical parafoil for autonomous guidance. To provide a soft landing for sensitive cargo, the system uses a round recovery parachute. A proprietary on-board guidance, navigation, and control system incorporates an integrated GPS and inertial navigation system to continually adjust to the flight characteristics of the system, as well as the weather conditions throughout the flight, to control the system to a pre-programmed altitude and position. The second, non-guided round recovery parachute deploys just prior to landing for a soft touchdown at its programmed point of impact.
Onyx flight patterns are controlled by having the controller interface with two steering winches, which are attached to the parafoil. The winches either draw in or pay out the parachute similar to that of the ailerons of an aircraft. Powering the winches are two Maxon motor and planetary gearhead combinations — one to adjust the right side of the parachute, and the other to maneuver the left side.
“Customization was necessary for our use,” says Daniel Preston, CEO & CTO of Atair Aerospace. “The motors are actually used at up to six times their rated output power.” Customizations 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 as well. “The motors needed to handle shock and vibration beyond what a typical motor would see,” Daniel said.
Even the planetary gearheads used in the systems had to be modified using special, non-standard materials to strengthen their capabilities. Different alloys and different heat treatments were used to provide the internal components of each gearhead. Although all customizations were initially completed by Maxon Motor at its factory, Atair has duplicated some of the specialized tooling needed so that elements of the customized motors can now be done in-house.
Atair has developed an adaptive control designed to increase the mission critical capabilities and flexibility in deploying Onyx systems. The adaptive control enables Onyx systems to fly correctly with gross variances in wing loading, asymmetrically-rigged payloads caused by pre-flight rigging errors or cargo changes, and even correct for damage induced while in flight. In fact, using real-time collision avoidance and swarming/flocking flight algorithms, Onyx can operate where multiple systems are deployed in the same air space. Dynamic payloads can be guided to one or multiple targets without the possibility of midair collisions. Each system controller operates in a decentralized fashion, so that there is no need for a supervisory control.
This article was written by Joe Martino, Sales Engineer, and Debora Setters, National Marketing Manager, at Maxon Precision Motor, Fall River, MA. For more information, visit http://info.hotims.com/10983-313.