Modelling and design of a reconfigurable AUV

The present study focuses on the modelling and design of a reconfigurable Autonomous Underwater Vehicle (AUV), intended for survey and hovering operations. The research activity is divided in two main areas of study: the control of the vehicle in survey configuration and the design of a mechanical assistance system for the reconfiguration process. The first part involves the development of a dynamic model for the system, with emphasis on kinematics expressed in quaternions, ensuring an efficient and singularity-free representation of rotations. Vehicle control is implemented through a PID controller for trajectory tracking, in order to evaluate the stability and precision of the system along predefined paths. The model validation is carried out via numerical simulations, incorporating the effects of hydrodynamic forces and ocean currents. The second part addresses a critical issue during configuration changes, focusing on the design of a system based on pulleys’ mechanism. Specifically, the study examines the material properties of the rope, the geometry of the pulley to be designed and the structural parameters of the system. Experimental tests on prototypes were conducted to validate the behaviour of the mechanism, with results compared to Finite Element Method (FEM) simulations. Finally, two distinct ratchet systems for cable tensioning and final component production are presented.