Design of an Underwater Robot Propelled by a Novel Class of Bio-Inspired Thrusters

In the last three decades, bio-inspired solutions have been investigated by researchers worldwide as a source of improvement for Autonomous Underwater Vehicles. In order to replace the screw propellers traditionally employed on marine vessels with more efficient bio-inspired thrusters, the authors of this paper have developed, manufactured, and tested a series of swimming robots in the last six years. The main design novelty, conceived and fine-tuned through these projects and prototypes, is the replacement of multiple inefficient servomotors, employed to drive the tails and fins of the robotic fish in the literature, with a single, efficient rotary actuator to solve control, encumbrance, and waterproofing issues. In this work, the single-motor design has been exploited to develop a swimming robot while pursuing the highest possible propulsive efficiency and the capability to perform low-speed and stationary turnabouts: the simulation performed on the multiphysics platform developed by the authors through their research have shown that the proposed solution can be applied to any robotic fish embodying a multi-joint tail mechanism regardless of the adopted swimming mode.