Flexible artificial muscle by bundle of McKibben fiber actuators

Abstract

McKibben actuator is well known as an artificial muscle because it realizes contraction force and displacement with high energy density. Therefore mechanical engineers have been applied the actuators to biomimetic robots, power assisting wear mechanisms and so on. Generally, “one” actuator has been used as “one” artificial muscle. Namely, if one artificial muscle of 10mm in diameter is necessary, one actuator of 10mm in diameter has been utilized. By the way, a muscle of actual creatures is a bundle of many muscle fibers. One muscle fiber is very thin and flexible. Therefore creature muscle can compensate its actuation even if some of muscle fibers are broken, and can have flexibility. In this study, focusing and mimicking the bundle mechanism, a rubber artificial muscle having multi thin rubber actuators have been developed. In this paper, we report basic characteristics of one actuator, geometric nonlinearity FEM analysis of the actuator and their bundle condition, and experimental results of fabricated rubber artificial muscle with multi actuators.