Adaptive observer based backstepping controller design for dynamic ship positioning
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Modified adaptive observer based backstepping control system for dynamic positioning of ship is proposed. As an improvement, the adaptive observer takes the first-order wave frequency model and the bias term which represent the slowly varying environmental disturbances and the unmodeled dynamics. Thus, the wave-frequency motions are filtered out, and only the reconstructed low-frequency motions are sent as inputs of the controller. Furthermore, as the ship dynamics parameters are unknown, the adaptive estimation law is designed for both the unknown ship dynamics and the unmeasured state variables. Based on the estimated states and parameters, backstepping controller considering the integral action is designed. Global exponential stability (GES) for the total system is proved using Lyapunov direct method. Simulation results show a good performance of the observer and control system.
KeywordsDynamic positioning backstepping control adaptive observer parameter estimation
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- Aarset, M.F., Strand, J.P. and Fossen, T.I., 1998. Nonlinear vectorial observer backstepping with integral action and wave filtering for ships, Proceedings of the IFAC Conference on Control Applications in Marine Systems, Fukuoka, Japan.Google Scholar
- Balchen, J.G., Jenssen, N.A. and Sælid, S., 1976. Dynamic positioning using Kalman filtering and optimal control theory, Proceedings of the IFAC/IFIP Symposium on Automation in Offshore Oil Field Operation, Holland, Amsterdam.Google Scholar
- Calugi, F., Robertsson, A. and Johansson, R., 2003. An adaptive observer for dynamical ship position control using vectorial observer backstepping, Proceedings of the 42nd IEEE Conference on Decision and Control, IEEE, Maui, HI, pp. 3262–3267.Google Scholar
- Fossen, T.I., 1994. Guidance and Control of Ocean Vehicles, John Wiley & Sons Inc., New York, USA.Google Scholar
- Fossen, T.I. and Perez, T., 2007. Marine Systems Simulator (MSS), http:// www.marinecontrol.orgGoogle Scholar
- Julier, S.J. and Uhlmann, J.K., 1997. A new extension of the Kalman filter to nonlinear systems, Proceedings of SPIE3068, Signal Processing, Sensor Fusion, and Target Recognition VI, SPIE, Orlando, FL, USA.Google Scholar
- Koditschek, D.E., 1987. Adaptive techniques for mechanical systems, Proceedings of the 5th Yale Workshop on Applications of Adaptive Systems Theory, Yale University, Yale, pp. 259–265.Google Scholar
- Torsetnes, G., Jouffroy, J. and Fossen, T.I., 2004. Nonlinear dynamic positioning of ships with gain-scheduled wave filtering, Proceedings of the 43rd IEEE Conference on Decision and Control, IEEE, Nassau, pp. 5340–5347.Google Scholar