Experimental comparison of identification methods for an open-frame ROV

This paper deals with the identification of hydrodynamic derivatives in a Remotely Operated Vehicle (ROV). In-water tests have been performed to identify yaw inertial and drag coefficients on the prototype ROV Roby2, developed at IAN. Vehicle heading has been measured losing a commercial digital fluxgate compass. A least square off line polynomial data fitting technique to compute signal derivatives is applied to experimental compass data. Subsequently, least squares and random-search algorithms are applied to experimental data to identify the vehicle model's coefficients. The experimental set-up and modalities are discussed and results of the least squares and random-research algorithms are compared.