When Robert Irving was diagnosed with Multiple Sclerosis it was the catalyst for him and his childhood friend, Richard Little, to put turn their engineering skills to the task of developing an exoskeleton that was a practical standing and walking alternative to wheelchairs. Little and Irving formed a company called REX Bionics which produces the Rex in Auckland, New Zealand.

The result is Rex, an exoskeleton made of strong, yet lightweight materials that is designed to support and hold a person comfortably as they move. It weights approximately 38 kg (84 pounds).Users strap themselves in to the robotic legs with a number of Velcro and buckled straps that fit around the legs along with a belt that fits around the user’s waist. Since this exoskeleton is designed to help the paraplegics rather than enhancing power, it is controlled with a joystick that sits at the wearer’s waist level.

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Users wearing Rex can stand up, walk, move sideways, turn around, go up and down stairs, as well as walk on flat, hard surfaces including ramps and slopes. It is designed for use on solid, stable surfaces such as those inside the home or workplace. It is not designed for use on slippery, unstable, or soft surfaces, on in areas that contain debris or small objects, such as ice, snow, sand, grass, mud or gravel.

Rex is designed to climb steps that meet typical building code standards for staircases – a minimum tread of 310 mm (12.2in), a maximum riser of 180mm (7in). It can walk on a curbed slope of up to 1:8 (7.1 degrees) and a general slope of up to 1:12 (4.8 degrees). It is powered by a custom-made rechargeable battery that will typically provide two hours of active use on a full charge. To extend running time the battery can be easily swapped out for a fully charged one.

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Before purchasing the Rex, potential customers will need to complete a medical check with their own physician as well as a series of checks for range of motion with a qualified physical therapist to ensure they have no contraindications to standing and walking. To meet Rex’s balance and loading constraints, customers will also need to be between 4’8” (146cm) and 6’4” (195cm) tall, with a weight of less than 220lb (100kg) and a hip girth of less than 14.9” (380mm). REX Bionics will also provide full training and a customized fitting over the course of approximately two weeks for buyers of the device.

The company says Rex is only really suitable for manual wheelchair users who can self-transfer and operate hand controls and Rex’s developers are quick to point out that REX is not intended as a replacement for a wheelchair, but as a complement to a wheelchair.

The company is in the process of concluding all the tests required prior to putting Rex on the market in Europe and Australia. It will also be seeking FDA approval so that Rex can be put on the market in the USA. REX Bionics CEO, Jenny Morel, says the company expects to conclude internal testing of Rex shortly and will then have a preliminary release in Auckland to allow the company to track what happens when people take Rex home. Sales are expected to commence in New Zealand by the end of 2010 and elsewhere by the middle of 2011.

Lockheed Martin’s un-tethered HULC exoskeleton is an anthropomorphic, electro-hydraulic design that currently operates on lithium polymer batteries. An onboard micro-computer senses the user’s actions and ensures the exoskeleton moves along with the operator. It gives its operator the ability to carry loads of up to 90kg (200 pounds) for extended periods of time and over all terrains. Compared to other exoskeletons, HULC robotic exoskeleton is much smaller and it weights less than 25kg (53 pounds).

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Beside the help in transporting weight without significant effort, it is also able to accelerate the wearer’s running up to 16 km/h (10 mph) in short bursts. Older models used lithium-ion batteries which could keep HULC operative for an hour. The folks from Lockheed Martin have selected Protonex Technology Corporation to develop power supply concepts that will enable the HULC robotic exoskeleton to support more than 72 hours of extended missions usage. Protonex will evaluate fuel cell-based power solutions that can be carried by the HULC, while at the same time powering the exoskeleton and the user’s mission equipment during extended dismounted operations.

“Integrating state-of-the-art power technology on the HULC is a whole system approach to meeting the needs of dismounted Warfighters and Special Operations forces,” said Rich Russell, director of Sensors, Data Links and Advanced Programs at Lockheed Martin Missiles and Fire Control. “With proper power management systems, the HULC can be used to recharge critical equipment while carrying heavy combat loads on an extended mission.”

Dismounted Soldiers often carry loads greater than 60kg (130 pounds), including electronics and numerous extra batteries needed to operate gear and complete multiple-day operations in the field. The HULC, equipped with an extended mission power supply with recharge capability, would enable dismounted Soldiers on these missions to carry fewer batteries. The HULC design maintains combat flexibility, allowing deep squats, crawls and upper-body lifting with minimal human exertion.

Protonex brings significant expertise in developing and manufacturing compact, lightweight and high-performance fuel cell systems for portable power applications in the 100 to 1000-watt range. The company’s fuel cell systems are designed to meet the needs of military, commercial and consumer customers for off-grid applications by providing customizable, stand-alone portable power solutions.

HULC is one of several technologies that Lockheed Martin is developing to support ground Soldiers. Lockheed Martin is a total systems solution provider to the military, including wearable situational awareness, a broad range of mobility assistance systems and power management systems.