Designing a metal hydride actuator with human-compatible softness and high power-to-weight ratio for future quality-of-life technologies

Abstract

Japan faces a rapidly growing elderly population that is unprecedented in the world. As a result, there are emerging needs for quality-of-life technologies, such as rehabilitation equipment, long-term care, and assistive devices. In particular, elderly people who are bedridden due to physical illnesses, such as cerebral stroke or bone fractures caused by a fall, may suffer awkward disuse syndromes (e.g., pressure ulcers, joint contracture, cardiac hypofunction, and mental depression). It is difficult for them to actively participate in rehabilitation exercises by themselves. Thus, to manage these disuse syndromes, we have developed a light and soft actuator device with metal hydride materials. This actuator device has a high power-to-weight ratio, adequate softness for human body support, noiseless motion, and a clean hydrogen energy system. The three apparatuses in which the metal hydride actuator is applied are a joint rehabilitation device for the hand, a seat lifter for a wheelchair or toilet, and a toe exercise apparatus for bedsore prevention. © 2013 Springer-Verlag Berlin Heidelberg.