A swimming robot with an internal rotor as a nonholonomic system

Two models of seemingly different classes of under actuated bio-inspired robotic systems are studied in this paper. The first model is that of an aquatic robot that swims like a fish. The second is a modified version of Chaplygin´s sleigh, a canonical nonholonomic system, that can move on the ground or a rigid surface. It is shown that a governing principle underlying the locomotion of both systems is the existence of a nonholonomic constraint. Having identified the common framework of non integrable constraints, an aquatic robot propelled by an internal rotor is presented.