CyPhy Works' UAVs use ground-based power to stay aloft indefinitely
By Darren Quick
December 5, 2012
Endurance is one of the biggest limiting factors of UAVs. To stay airborne longer, Boeing has turned to hydrogen to fuel its Phantom Eye, Qinetiq’s Zephyr relies on solar power and Northrop Grumman’s Global Hawk can refuel autonomously in mid-air. But CyPhy Works has taken a different approach with its first UAVs. By connecting to a ground-based power source via a “microfilament,” the UAVs are able to stay aloft indefinitely.
Founded by iRobot co-founder and former Chairman Helen Greiner, the Massachusetts-based CyPhy Works is aiming to “design and deliver innovative robots.” Drawing power from a ground-based source by way of a continuous cable might at first glance seem like a step backwards in terms of UAV innovation, but the company is keen to point out the advantages of its cabled system used in its first two UAVs.
The EASE (Extreme Access System for Entry) is a small vehicle that, with a diameter of 12 inches (30 cm) and height of 16 inches (41 cm), is designed to be able to fly through doors and windows and fit inside a standard backpack when not in use. It features a ducted-fan design that gives it vertical takeoff and landing and hover capabilities.
Designed as a man-portable system, EASE is designed to be powered by batteries in the base station that should keep EASE in the air for 50 minutes. However, the batteries are hot-swappable, enabling EASE to stay aloft as long as there are batteries available. EASE can also be powered by a properly equipped vehicle or, with the use of an additional AC-DC converter, a generator or the grid. However, to keep the weight of the system down, an AC-DC converter isn't part of the core system.
Whatever the source, power is supplied from the ground via a fishing-line thin microfilament cable made up of two strands of copper wire that is spooled out from the UAV itself. CyPhy Works says the EASE’s onboard spooler gives the vehicle greater mobility and ensures there is no tension placed on the cable even if it gets tangled in a tree branch or other obstacle.
As well as supplying power, the microfilament is also used to communicate with a lightweight ground control station (GCS), which serves as the UAV’s remote brain. The company is keeping the design of the GCS under wraps for now, but CyPhy Works’ Lead Roboticist and Director of Operations, Jason Walker, did tell us that high definition video captured on the EASE’s cameras is displayed on the GCS itself. The GCS is also able to output video to an external monitor or stream it over a network.
Speaking of the cameras, EASE comes with two color HD cameras – one front looking and one down looking – as standard, with a thermal camera also available as an option. The company points out that the cabled connection allows 720p video at 30 fps to be monitored in real time, unlike the choppy, low res video provided by wireless systems that can cut out completely when a UAV rounds a corner or enters a building. Additionally, this video can’t be intercepted or jammed and the aircraft itself can’t be spoofed.
With a range of 1,000 ft (305 m), the EASE can operate up to a height of 300 ft (91 m) above ground level, at altitudes of up to 7,000 ft (2.1 km).
The Persistent Aerial Reconnaissance and Communications (PARC) system employs a more familiar quadrotor design and is significantly larger than its stablemate. Intended for staying higher, longer to provide a persistent eye in the sky, the PARC system is designed to be connected to the grid, a generator or a vehicle for its power needs.
The PARC system also works in conjunction with a GCS and receives its power via a microfilament. However, these are different to the GCS and spooling mechanism used with EASE. Although CyPhy isn’t ready to reveal details of the PARC system's spooling mechanism, it will enable the aircraft to hover at heights of up to 1,000 ft (305 m) at altitudes of up to 11,000 ft (3.4 km). And if the UAV does run into problems and the cable is cut, it won’t just plummet from the sky, with an onboard back-up battery providing enough power for it to safely return to base.
The vehicle measures 55 inches (140 cm) in diameter and 16 inches (41 cm) high and carries two gyro stabilized, gimbal-mounted cameras – a 720p color camera with 10x optical zoom and 1.0 lux low light capabilities, and a 640 x 480 resolution thermal camera. It also boasts additional payload capacity for carrying sensors or communications devices.
Walker emphasized that both the EASE and PARC systems are designed around CyPhy Works’ “no-pilots” philosophy, so that the operator doesn’t really “fly” the aircraft but guides it to what they want to see. The GCS does the navigation processing grunt work and presents the relevant data to the user in a simple and usable way.
While Walker describes EASE as a teleoperated system in its current form, the CyPhy team anticipates providing it with increased autonomy capabilities in the future. PARC, on the other hand, is already almost completely autonomous. While there are controls on the GCS for adjusting the craft’s altitude and heading, the majority of the GCS controls are devoted to controlling the craft’s payloads.
Walker says the robots have already attracted interest from military, commercial and civil users but, due in large part to airspace usage restrictions, the military is likely to be the first place the UAVs spread their wings. However, Walker adds that the aircraft also have great potential for use in emergency and disaster response situations, as well as for law enforcement agencies in documenting traffic accidents and crime scenes.
The video below shows a flight test of EASE at the McKenna MOUT Site at Ft. Benning, Georgia.
Editor's Note: This story was amended on Dec. 7, 2012, to clarify the EASE's alternative power source options, the PARC system's (not the EASE) capabilities to return to base in the event of damage to the microfilament and clarify that the PARC system uses a different GCS to EASE.