An Untethered Bionic Robotic Fish Using SMA Actuators

Abstract

The authors develop a bionic robotic fish that has a soft tail using smart material as an actuator. Two sets of shape memory alloy (SMA) wires are stitched inside of the soft tail, which would let the tail bend in both sides. The designed structure is expected to gain the ability to imitate the swimming posture of a real fish in the water to swim straight and could turn left and right by employing the body and the caudal fin (BCF mode). The streamline of the body and head part are designed by a 3D CAD, and then printed by a high precision 3D-printer. The robotic fish system is governed by an infrared remote controller, which sends signals to a micro Arduino computer inside the fish body for controlling the swimming motion and the speed. We study the relations between the control signals and the robotic swimming behavior. The swimming motion under a low and a high frequency are analyzed.