ModiFiber: Two-Way Morphing Soft Thread Actuators for Tangible Interaction

Despite thin-line actuators becoming widely adopted in different Human-Computer Interaction (HCI) contexts, including integration into fabrics, paper art, hinges, soft robotics, and human hair, accessible line-based actuators are very limited beyond shape memory alloy (SMA) wire and motor-driven passive tendons. In this paper, we introduce a novel, yet simple and accessible, line-based actuator. ModiFiber is a twisted-then-coiled nylon thread actuator with a silicone coating. This composite thread actuator exhibits unique two-way reversible shrinking or twisting behaviors triggered by heat or electrical current (i.e., Joule heating). ModiFiber is soft, flexible, safe to operate and easily woven or sewn, hence it has a great potential as an embedded line-based actuator for HCI purposes. In this paper, we explain the material mechanisms and manufacturing approaches, followed by some performance tests and application demonstrations.