Design, Construction, and Modeling of a BAUV with Propulsion System Based on a Parallel Mechanism for the Caudal Fin

Traditional propulsion systems for autonomous underwater vehicles (AUVs) have several deficiencies, such as the invasion of the aquatic environment through the generation of noise and damage to the ecosystem, higher energy consumption, and a unidirectional thruster vector. The last characteristic constrains the maneuverability of the vehicle. This paper proposes a 3-DOF spherical 3 universal-cylindrical-universal and 1 spherical joint (3UCU-1S) parallel mechanism coupled to an artificial caudal fin to produce a vectored thruster for a biomimetic AUV (BAUV). First, the design and construction of the prototype are described. Then, the kinematics and dynamics analysis of the parallel mechanism is presented. Finally, a motion study shows the types of movements that can be achieved with the mechanism to perform flapping of the caudal fin in different directions.