Comparison of smart artificial muscles with different functional fibers

Abstract:
A McKibben artificial muscle is a soft actuator that is driven by pneumatic pressure. This artificial muscle consists of a rubber tube and a sleeve made of knitted fibers. By applying pneumatic pressure to the rubber tube, the artificial muscle contracts axially with changing fibers angle. Because of high safety due to flexibility and simplicity, the artificial muscle is expected to be applied to robots or power assist devices in medical, welfare, and agricultural fields. However, for sensing its state, external sensors such as pressure sensors, potentiometers, or encoders are needed in general. By attaching these rigid and bulky sensors, the advantages of the artificial muscle are diminished. In our study, three kinds of functional fibers are utilized as sleeve fibers. The functional fibers work as not only actuator elements but also sensor elements. In this paper, the braiding process of the functional fibers is clarified, and the function realized by each functional fiber is compared.