Safety Critical Control, Information and Transportation Systems: Parametric Resonance
Contacts: Professor Thor I. Fossen and Professor Anton Shiriaev

Safety critical control and information systems onboard ships are receiving more and more attention. Parametric resonance is a nonlinear phenomenon where changes in the model parameters induce a resonance in roll which can make the ship to capsize. This is known to occur for the rolling of ships with significant changes of restoring (spring) characteristics due to wave passage along the hull and wave excited vertical motions - typical ships affected by this are fishing vessels and container ships. The phenomenon is characteristic when sailing in head or stern seas with wave lengths similar to the ship length, encounter frequency of about twice the roll natural frequency, and wave heights above a ship-dependent threshold value. The phenomenon is highly nonlinear and time-varying.

The main research goals are construction of control and information systems to detect parametric resonance onboard sailing ships and prevent large motions by active control (roll tanks/fins stabilizers, speed and heading changes). We have already established international cooperation with Professor Marcelo Neves, Federal University of Rio de Janeiro on nonlinear modeling on parametric resonance. In addition, we cooperate with Professor Mogens Blanke at the Technical University of Denmark. This work focuses on fin stabilization.

Experiments with a container ship at NTNU have been conducted in a towing tank. Parametric roll resonance was observed in many runs and further experiments with active anti-roll tanks are planned. One PhD student, Christian Holden, is currently assigned to the project. The plan is hire a second PhD student and a Post Doc. This will be joint work between CeSOS and the Department of Engineering Cybernetics. Relevant references are:

• France, Levadou, Treakle, Paulling, Michel and Moore (2001). An investigation of head-sea parametric rolling and its influence on container lashing systems. SNAME Annual Meeting.
• Holden, Galeazzi, Rodríguez, Perez, Fossen, Blanke and Neves (2007). Nonlinear Container Ship Model for the Study of Parametric Roll Resonance. Modeling, Ident. and Control, MIC-28(4).
• Holden, Galeazzi, Fossen and Perez (2008). Nonlinear Lyapunov Stabilization of Parametric Roll Resonance with Active U-Tanks. Submitted to the CDC’08.
• Holden, Perez and Fossen (2007). Frequency-Motivated Observer Design for the Prediction of Parametric Roll Resonance. Proc. IFAC CAMS’07.
• Neves and Rodríguez (2006). On unstable ship motions resulting from strong nonlinear coupling. Ocean Engineering, vol. 33.
• Rodríguez, Holden, Perez, Drummen, Neves and Fossen (2007). Validation of a Container Ship Model for Parametric Rolling, Proceedings of the 9th International Ship Stability Workshop.
• Tondl, Ruijgrok, Verhulst and Nabergoj (2000). Autoparametric Resonance in Mech. Systems.