Assistive exoskeletons are a bit like electric bikes – they do indeed give users a power boost, but part of that boost is needed just to move the extra weight along. Japanese researchers at Hiroshima University and Daiya Industry Co., however, have created a minimalist exoskeleton that does away with heavy batteries and motors. Instead, their Unplugged Powered Suit (UPS) harnesses the wearer's own weight.

The UPS consists of a pump located under the sole of the user's foot, an air hose that runs up the leg from that pump, and what's known as a Pneumatic Gel Muscle (PGM).

With each step that the wearer takes, their foot presses down on the pump. This pushes air up the hose to a hip belt, where it's relayed into the PGM. There, it temporarily causes a gel contained within the device to compress, causing the whole thing to contract and relax like a natural muscle.

Depending on exactly where the pump and PGM are located under the foot and on the leg (respectively), different forms of support are possible. In one configuration, less overall effort is required to maintain a jogging pace. In another, the speed at which the user's legs move forward while walking is increased.

"The UPS is designed to support human motion where and when needed," says Associate Professor Yuichi Kurita (seen above). "This means that we can customize the UPS to the user's particular needs such as muscle strength for athletes and rehabilitation. In the future, we can develop smarter assistive suits including wearable actuators and sensors by using our technique."

The system, which is also said to be inexpensive to build and easy to maintain, will be on display this month at the International Robot Exhibition 2015 in Japan.

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