A wire-driven robotic shark with a non-uniform stiffness distribution fish tail

Inspired by the muscle-driven mechanisms of natural fish, wire-driven robotic fish have emerged as a prominent research focus. This paper presents a wire-driven robotic shark (WRS) featuring a flexible tail with non-uniform stiffness distribution. To examine the effects of stiffness distribution, wire installation position, and swimming parameters on the tail's undulating motion, a series of numerical simulations were conducted using a Fluid–Structure Interaction (FSI) method. An experimental platform was subsequently developed to investigate forward swimming and turning performance. The results demonstrate that stiffness distribution, wire installation position, and swimming parameters significantly influence the undulating posture of the tail. The structurally optimized WRS achieved a maximum swimming speed of 0.53 BL/s and a maximum average turning speed of 24°/s.