Novel Twisted and Coiled Polymer Fiber Actuator Fabricated From Polymer-Coated Optical Fiber

This study proposes a novel twisted and coiled polymer fiber (TCPF) actuator fabricated from a polymer-coated optical fiber. The TCPF actuator is a soft actuator that is driven by heating; the TCPF actuator in combination with a cooling system has been widely studied for applications in robotics. Sensing is a major issue in such units; in particular, temperature sensing is important for the safe usage of the TCPF. To achieve this, the electrical properties of the heating wire are typically utilized. However, this method is affected by the input voltage noise because the circuit used for actuation is the same as that used for sensing. To separate these circuits, this study developed a temperature-sensing method for the TCPF based on an optical fiber. For propagating only the heat of the polymer to the optical fiber, we embedded the optical fiber in the TCPF. This study experimentally demonstrated that the TCPF actuator fabricated using the polymer-coated optical fiber can be driven by heating. Furthermore, using the developed sensing method, we achieved temperature and force control under isometric conditions.