Comparative study of algorithms for obtaining reduced order state-space form of radiation forces

In this paper, efficient state-space formulations are presented to represent frequency-dependent added mass and potential damping in the equations of motion for a surface ship. This is of interest in design of marine control systems, and in real-time simulators of marine systems. We investigate the structural properties, e.g. passivity, of the radiation forces. Subsequently we look at the state-space realizations of the radiation forces, and how the structural properties are contained in these models. The state-space models are of high order and it is necessary to use model reduction techniques to make them efficient for computer simulation and control synthesis. Finally, we investigate different model reduction procedures applied on the state-space models of the radiation forces, and compare them in terms of accuracy, complexity and algorithm cost.