Associate Professor Yuichi Kurita and Kazunori Ogawa are developing an Unplugged Powered Suit at Hiroshima University in conjunction with Daiya Industry Co. Ltd., Japan. This is a passive, pneumatic exoskeleton that is composed of three main parts: Pneumatic Gel Muscle (PGM), a connection hose and a pump under the heel (or under the toes of the foot, depending on the configuration). The PGM for the Unplugged Powered Suit (UPS) was specifically created to actuate using low pressure. The small air pump under the sole therefore provides enough pressure to power the suit. This removes the need for a gas compressor, which can be noisy, heavy, produce a lot of heat and vibrations and require a lot of power.
The Unplugged Powered Suit was on display at the International Robot Exhibition 2015 in Tokyo. The Japanese website NewSwitch was able to take a picture of the UPS at the show (right). According to the NewSwitch article (Japanese language), the foot pump is able to generate up to 21 PSI of pressure, which is quite high for a small pump like this. The pressure from the foot pump can then be used to power the gel muscle(s) in the opposite leg, same leg or in the arm and shoulder depending on the configuration.
The idea to have a heel device that collects energy is not new. The heel strike during the natural walking gait cycle is considered to be wasted energy. In the past there have been spring loaded or otherwise elastic devices that try to extract energy during the heel strike. Other research groups have produced shoe inserts that change the morphology of the foot so the energy of the heel strike can be harnessed as electricity or used during foot lift. The Unplugged Powered Suit is a novel idea on an already familiar concept. Usually devices like this suffer from being inefficient, with the cost of wearing the wearable far outweighing the benefit. It will be interesting to see what test data Professor Yuichi Kurita’s group collects in the future. In the meantime, the UPS appears to be relatively simple so it is possible for DIY enthusiasts to try making their own using the Soft Robotics Toolkit and a lot of imagination to fill in the gaps.
Finally, Professor Yuichi Kurita’s group has posted a YouTube video which shows in more detail the new Pneumatic Gel Muscle and various configurations and applications of the Unplugged Powered Suit:
…When the pneumatic artificial muscle covers articulatio coxae muscle and the pump is set on the contralateral sole, the assist force can support hip movements in swing phase. By changing the attachment position of the artificial muscle, users can freely select the muscles to be unloaded. The UPS has potential to support humans in various motions. By taking advantage of the flexibility and safeness, the UPS will be applied to sports, fitness and training use. –YouTube