Design and experimental study of a wire-driven bionic fishtail actuator

Inspired by natural fish, a bionic fishtail actuator, fabricated from a silicone sheet, was designed. The flapping frequency and angle can be achieved by manipulating the drive wire. The motion characteristics of the bionic fishtail were analyzed under various silicone hardness settings, as well as under both inelastic and elastic drive wire scenarios. The results indicate that the thrust under elastic drive wire conditions is obviously inferior to that observed under inelastic drive wire conditions. However, incorporating an extra elastic wire into the inelastic wire-driven fishtail improved the average thrust marginally, which led to better performance when imitating the C-start escape response, especially. For the S40 backbone, the addition of the elastic wire yielded an average C-start thrust of 5.78N, representing a 15% increase compared to its absence. •A wire-driven flexible bionic fishtail actuator is designed to imitate the C start escape response of natural fish.•The impact of elasticity in the drive wire on the kinematic performance of a bionic fish tail is analyzed and compared.•The thrust can be increased by incorporating additional elastic wires based on the inelastic wire actuator.