LMI‐based passivation of LTI systems with application to marine structures

Due to the inherent relevance of passive (physically representative) models for control, state‐estimation, and motion simulation in the field of marine systems, in this paper, an optimisation‐based approach to passivation of linear time‐invariant (LTI) systems is proposed with application to physically consistent dynamical modelling of marine structures. In particular, the presented strategy is based upon the introduction of a suitably designed perturbation, computed via minimisation of a linear objective subject to a specific set of linear matrix inequalities (LMIs). The performance of the passivation technique is showcased in terms of two case studies: An offshore platform, with a frequency‐domain response computed by means of hydrodynamic codes, and a 1:20 scale wave energy converter (WEC), is characterised in terms of real experimental data.