Performance Evaluation of Conductive Fiber-Coated Twisted and Coiled Polymer Actuator (TCPA) Unit with a Helical Fiber Structure

Recently, robotics and wearable technology have increased demand for actuators capable of delivering flexible and adaptive motions that rigid mechanisms cannot provide. Twisted and coiled polymer actuators (TCPAs) made from nylon fishing lines show promise owing to their low cost, ease of fabrication, and high deformation capabilities. However, conventional heating methods using copper or nichrome wires are frequently limited by low thermal response rates and durability issues. In this study, we introduce a new heating technique in which five conductive fibers are twisted together and uniformly wrapped around the TCPA to improve heat transfer efficiency and allow operation at higher input voltages. In addition, we propose a unit design that bundles multiple TCPAs into a helical fiber structure (CF‐HFS TCPA) for increased force generation. Experimental results show that the performance of single TCPACF units is strongly dependent on wire gauge: under light loads of approximately 1. 96–2. 45 N, finer wires achieve higher displacement ratios at high voltages, whereas under loads of approximately 2. 94 N, their performance declines, while thicker wires maintain stable operation over a wider load range. Temperature measurements show that, while gauges achieve high surface temperatures under light loads, the temperature rise is reduced under heavy loads owing to reduced contraction and increased heat dissipation. Overall, these findings support the potential utility of our approach as an effective method for developing actuators for soft robotic and wearable applications.