Undulatory fin propulsion, inspired by the swimming of knifefish, rays and cuttlefish, could potentially endow underwater vehicles with precision manoeuvrability and stable station-keeping, in the context of applications such as underwater structure inspection and maintenance. The interest for this bio-inspired propulsion scheme stems mainly from the thrust vectoring capability of undulatory fins, and from the ability to integrate them into rigid-body underwater vehicles. Other postulated advantages of undulatory fins, compared to conventional propellers, include increased energy efficiency, reduced sediment disruption and stealth operation.
The SQUIDBOT-mini robot, is a compact-size, fully untethered underwater vehicle propelled by a pair of laterally-mounted undulatory fins, each one featuring three actuated rays. Two coupled Central Pattern Generator (CPG) networks are employed to produce the rays’ motion profile.
The prototype is equipped with an Attitude Heading Reference System (AHRS), a depth sensor and a Pixy vision system, which are utilized in the implementation of closed-loop schemes for motion control of the vehicle.