Nonlinear Attitude Control of a Spherical Underwater Vehicle

• Main Authors: Ramon A. Suarez Fernandez, E. Andres Parra R., Zorana Milosevic, Sergio Dominguez, Claudio Rossi
• Format: Article
• Language: English
• Published: MDPI AG 2019-03-01
• Series: Sensors
• Subjects: underwater robots; AUV; spherical robots; feedback linearization; mine exploration
• Online Access: https://www.mdpi.com/1424-8220/19/6/1445

In this work, we present the design, implementation, and testing of an attitude control system based on State Feedback Linearization (FL) of a prototype spherical underwater vehicle. The vehicle is characterized by a manifold design thruster configuration for both locomotion and maneuvering, as well as on a novel pendulum-based passive pitch control mechanism. First, the mechanical design and onboard electronics set up of the spherically shaped hull are introduced. Afterward, a high-fidelity dynamic model of the system is derived for a 6 degree-of-freedom (DOF) underwater vehicle, followed by several experiments that have been performed in a controlled environment to compare the performance of the proposed control method to that of a baseline Proportional-Integral-Derivative (PID) controller. Experimental results demonstrate that while both controllers were able to perform the specified maneuvers, the FL controller outperforms the PID in terms of precision and time response.