Electromagnetic Actuation Based Swimming Robot with Semi-Flexible Fins

In this paper, A miniature (120 mm) bio-inspired underwater robot is presented which employs labriform or drag-based swimming and is capable of moving at an average speed of 2.7 cm/s (0.25 BL/s). The robot is equipped with a novel electromagnet-based actuator, and when coupled with a permanent magnet, it actuates the fins of the robot thus producing net propulsion. Traditional Contact-based actuators, that are employed for propulsion in the robots' fins are prone to accidents and require waterproofing, hence a contactless actuator has been developed, which eliminates the need for waterproofing of the actuator and is best suited for underwater applications as the excess heat, generated by the electromagnets is dissipated into the surrounding water. A concave-shaped semi-flexible fin has been designed, which changes its geometry in recovery and power stroke to minimize the hydrodynamic drag force and increase the thrust. This reduced the design complexities of the robot and allowed more room for sensors and other equipment. The designed robot has the potential to form the basis for underwater swarm robots for exploration of seabed, natural resources, inspection of underwater cables, academic research and military applications.