An Identification Scheme to determine All Off-Diagonal Elements of Added-Mass Matrix for Marine Vessels

Abstract

Abstract This paper presents an approach to identify the off-diagonal elements of the added mass matrix of a fully actuated marine vessel based on a set of experiments. The off-diagonal elements of the mass matrix characterize the coupled acceleration response of the vessel and are therefore required for the intended design of a control system. The introduced identification scheme utilizes the equivalence between the mass matrix and the coupled acceleration response. The process is extended by a compensation that attempts to match the coupling. A few acceleration experiments are performed with the vessel, applying different compensations for testing. Based on the tested compensations and the measured acceleration responses, the exact compensation and the mass matrix can be reconstructed finally. The exact compensation is sometimes desired itself, rather than the off-diagonal elements of the mass matrix. It makes the coupled process appear as separate SISO processes, which is convenient for controller design.