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The Human Exoskeleton

By Ranica Arrowsmith, Associate Editor | August 28, 2015

The robotic exoskeleton industry is still young but expanding slowly as technology improves.

Colorado potato beetle

An exoskeleton is, as the word suggests, a skeleton that exists outside the body. Insects and crustaceans have most well-known examples of this body type. Many species of insect, such as the Colorado potato beetle pictured, have a hard exterior shell instead of an interior skeletal network (endoskeleton) that provides support and protection to the body. Humans, of course, have endoskeletons. But sometimes, neurological conditions and injuries limit the mobility of the body, rendering the human musculoskeletal network almost redundant. Robotic exoskeletons have emerged in the past decade as a solution for people who are unable to move on their own. Robotic exoskeletons attach, to varying degrees, to the outside of the human body, and work via a combination of sensors, software, motors, pistons and lightweight materials to help the immobile move again. Here are a few examples of exoskeletons available for medical use today.

The ReWalk exoskeleton made by Argo Medical Technologies

Currently, ReWalk is the only exoskeleton cleared by the U.S. Food and Drug Administration (FDA) for rehabilitation and personal use in the United States. ReWalk is a wearable robotic exoskeleton that provides powered hip and knee motion to enable individuals with spinal cord injury (SCI) to stand upright, walk, turn, and climb and descend stairs. ReWalk has intricate motion sensors that measure the client’s upper body movements and shifts in gravity. These signals are processed by an onboard computer system that initiates and maintains walking in the desired direction at the appropriate speed. The machine was created in Israel by mechanical engineer Amit Goffer, Ph.D. (pictured), who was left tetraplegic by a road accident in 1998. Argo Medical Technologies Ltd., which makes ReWalk, earned FDA clearance for the exoskeleton in 2014.

The HAL exoskeleton made by Cyberdyne

Cyberdyne Inc. makes the HAL (hybrid assistive limb) exoskeleton (pictured) for people who have disorders in the lower limb and people whose legs are weakening. Cyberdyne was founded as a robotics spin-off of the University of Tsukuba in Japan, but HAL is currently only approved for sale as a medical device in the European Union. In Japan, the robot is approved for non-medical use.

The Ekso exoskeleton made by Ekso Bionics

Ekso, made by Ekso Bionics Holdings Inc., is a wearable bionic suit that enables individuals with any amount of lower extremity weakness to stand up and walk over ground with a natural, full weight bearing, reciprocal gait. Walking is achieved by the user’s weight shifts activating sensors in the device, which then initiates steps. Battery-powered motors drive the legs, replacing deficient neuromuscular function. According to the company, Ekso provides a means for people with mobility conditions including complete paralysis and minimal forearm strength to stand and walk. It also reportedly helps patients re-learn proper step patterns and weight shifts. Ekso Bionics has been developing this technology since 2005.

The Lokomat exoskeleton made by Hocoma

Lokomat, made by Hocoma Inc., is used by several physical therapy centers in the United States. According to the company, the Lokomat improves patient outcomes in physical therapy by increasing therapy volume and intensity, providing task-specific training and increasing patient engagement. Hocoma touts Lokomat as very well suited for neurological patients.

The Body Extender created at Perceptual Robotics Laboratory

Although it is not intended for medical use, the Body Extender is claimed to be “the most complex wearable robot that has been ever built in the world,” according to mechanical engineer Fabio Salsedo. Salsedo lead the project that built this exoskeleton, which is used to track the complex movement of the human body and amplify the force of the operator. The machine was developed at the Perceptual Robotics Laboratory (Percro), part of the Pisa’s Scuola Superiore Sant’Anna in Italy. It can lift 110 lbs. in each extended hand and can exert 10 times the force the user applies to an object. “The idea is to get robots out of factories where they have shown their worth and to transform them into household machines which can live together with humans,” said Professor Paolo Dario, director of the college’s bio-robotics department. The Body Extender’s creators aim to make the machine available for use in disaster relief efforts such as earthquakes. It is not commercially available yet.