What is Artificial Muscle

Metal hydride materials can store a huge amount of hydrogen and can convert energy due to enthalpy change through a hydride reaction. Artificial actuation systems that employ this special physicochemical property are named metal hydride actuators. The actuators utilize the mechanical energy formed from hydrogen equilibrium pressure through thermal energy given to the metal hydride alloys as output. Metal hydride actuators have a simple structure and a number of features that make them attractive for use in rehabilitation engineering and assistive technology. They provide a high power-to-weight ratio, high strain actuation, human-compatible softness and noiselessness, and they are environmentally benign. The behavior of metal hydride actuators is also useful for overall human-machine interface applications. This article reviews the motivation for the development of some of the leading artificial muscle-like actuators, outlines the metal hydride actuators and describes its applications in quality-of-life technology.