In Robotics, what is an Exoskeleton?

In robotics, an exoskeleton, also known as a powered exoskeleton, is a powered suit that is used to magnify human strength and/or speed. The concept has had extensive treatment in science fiction, but only very recently has it begun to acquire plausibility in the real world. The concept has acquired the most attention from the US military and robotics-oriented Asian countries like Japan and South Korea. As of 2009, exoskeletons have been built, but are not widely deployed. Neither are exoskeletons widely available commercially, but that could soon change. In 2008, one company, Cyberdyne of Japan, began renting out its suits.

The first serious effort to construct a powered exoskeleton, conducted by General Electric in 1965, was called Hardiman. The intent behind the project was to create an exoskeleton that a person could use to lift 1500 lbs (680 kg), almost a ton. The project failed. Attempts at using the full exoskeleton resulted in violent uncontrolled motion which would have ripped a user limb from limb. The suit itself weighed 1500 lb (680 kg) and could only lift 750 lb (340 kg) when it could move at all. The suit was never turned on with a person inside.

Breakthroughs in creating practical exoskeletons did not occur until the early 2000s. Around this time, decades of research by organizations like the United States Defense Advanced Research Projects Agency (DARPA) finally paid off. Various groups successfully constructed prototypes of powered exoskeletons. Some currently existing (limited) exoskeletons include Cyberdyne's HAL 5, Honda's Exoskeleton Legs, the MIT Media Lab's Biomechatronics Group legs, and the Sarcos/Raytheon XOS Exoskeleton. The specs of these suits vary and some have not been released. The HAL 5 (Hybrid Assistive Limb) is marketed as being capable of enhancing the lifting capacity of the user by fivefold.

Two major applications of exoskeletons would be in the military and in medical care. For the military, powered exoskeletons would allow soldiers to carry heavier weapons and more tools and ammo. The concept of a powered exoskeleton is a central theme in the US Military's vision for a next-generation Army. In January 2007, it was reported that the Pentagon had given funds to University of Texas nanotechnologist Ray Baughman to develop myomer fibers as "muscle" for powered exoskeletons. For medical care, researchers at several universities in Japan have designed soft exoskeletons designed to help medical caretakers carry the old or infirm. So, exoskeletons could have applications in both war and peace.

Still, there are several major obstacles in developing effective exoskeletons. The biggest are improving power-to-weight ratios (which could be helped by using fibers instead of conventional mechatronics) and battery life.