Experimental model identification of a vessel with a bow–stern azimuth thruster configuration under bollard pull conditions

KU Leuven developed Maverick, an over-actuated autonomous vessel with bow and stern azimuth thrusters. This study experimentally identifies a thruster model under bollard pull conditions with the azimuth angles of both thrusters fixed at 0°, mapping commanded motor power to total thrust. Feedback signals of electrical power and propeller speed were also logged to derive an indicative relationship between torque and thrust. Experiments revealed performance degradation when both thrusters operated simultaneously and the bow thruster was at high load, because its wake reduced the stern thruster's effective thrust. This interaction was integrated into the model through a configuration-specific thrust-reduction term. The obtained model can support subsequent maneuvering model development and thrust allocation design for Maverick. Extension to non-bollard conditions or arbitrary azimuth angles requires additional modeling of inflow effects and thrust vector projection. This approach may apply to vessels with similar configuration, providing a straightforward method for modeling such systems.