BCF swimming locomotion for autonomous underwater robots: a review and a novel solution to improve control and efficiency

The development of autonomous, energy efficient, underwater robots for large areas exploration has been attracting many researchers, since their use can be effective in several applications. In order to improve the propulsion efficiency, movement capability and situation awareness, last studies have been directed on biomimetic robots. Over millions of years in a vast and often hostile realm, fish have evolved swimming capabilities far superior in many ways to what has been achieved by nautical technology. Instinctively, they use their superbly streamlined bodies to exploit fluid-mechanical principles, achieving extraordinary propulsion efficiencies, acceleration and manoeuvrability. Their solutions achieved the best performances based on aspects like preys hunting and living conditions. Looking at nature for inspiration as to how design an Autonomous Underwater Vehicle can significantly improve its flexibility and efficiency. This paper presents an examination of the state of the art on biomimetic robotic fishes, underlining the reasons why bio-inspiration can be a winning move and discussing how fish swimming can be the line of sight of the future locomotion technology. The paper concludes with a novel mechanism proposal, designed to produce optimal oscillatory motion between the flexible parts constituting the hull of the robotic fish.