Soft Linear Actuator Utilizing Electrically Vibrating Threads

Various soft actuators have been developed in the past, achieving flexible motion. However, soft actuators that combine high force and high work have not yet been realized. The ratchet movement between actin and myosin, which causes muscle contraction in living organisms, could potentially lead to such high-efficiency soft actuators. In this paper, we describe a thread-based soft linear actuator inspired by this biological principle. The mechanism of this actuator utilizes the interaction between threads and objects to generate motion. Multiple units could be stacked to produce high force when used as a contracting actuator. To verify the principle of the proposed mechanism, we conducted transport experiments. The object placed on the threads was successfully transported at a speed of 2.2 mm/min.