Nonlinear identification of mooring lines in dynamic operation of floating structures

Abstract

An adaptive algorithm for on-line estimation of physical coefficients of cables in viscous environment is presented. The procedure is useful for obtaining cable characteristics, which are needed in stability analysis and control system design for moored floating structures. It uses measurements of position and forces from on-board instrumentation. It is also able to track changes in the depth and to test for parameter consistency in order to confer the esti- mation robustness with respect to dynamic perturbations. It is based on nonlinear solvers, which can cope with transcendental functions o fthe model structure. The proo fo fasymp- totic convergence is presented. Finally, three basic case studies are analyzed.