## “Design of a dynamic positioning system using model-based control”Authors: Asgeir J. Sørensen, Svein I. Sagatun and Thor I. Fossen,
Affiliation: ABB and NTNU, Department of Engineering Cybernetics
Reference: 1996, Vol 17, No 2, pp. 135-151. |

**Keywords:**Dynamic positioning, model-based control, hydrodynamics, sea trials, marine systems

**Abstract:**A dynamic positioning (DP) system includes different control functions for automatic positioning and guidance of marine vessels by means of thruster and propeller actions. This paper describes the control functions which provide station-keeping and tracking. The DP controller is designed using model-based control, where a new modified LQG feedback controller and a model reference feedforward controller are applied. A reference model calculates appropriate reference trajectories. Since it is not desirable nor even possible to counteract the wave-frequency movement caused by first-order wave loads, the control action of the propulsion system should be produced by the low frequency part of the vessel movement caused by current, wind and second-order mean and slowly varying wave loads. A Kalman filter based state estimator and a Luenberger observer are used to compute the low-frequency feedback and feedforward control signals. Full-scale experiments with a supply vessel demonstrate the performance of the proposed controller.

PDF (1803 Kb) DOI: 10.4173/mic.1996.2.6

**DOI forward links to this article:**

[1] S. Spry and K. Hedrick (1999), doi:10.1109/ACC.1999.783616 | |

[2] Linlin Wang, Wenhua Wang, Yazhen Du and Yi Huang (2018), doi:10.1007/s00773-018-0584-9 | |

[3] Shuyan Xia, Daolin Xu, Haicheng Zhang and Yousheng Wu (2018), doi:10.1016/j.jsv.2018.10.006 |

**References:**

[1] BALCHEN, J.G. (1993). A modified LQG algorithm, MLQG for robust control of nonlinear multivariable systems. Modeling, Identification and Control, 14, pp. 175-180 doi:10.4173/mic.1993.3.5

[2] BALCHEN, J.G., JENSSEN, N. A. SÆLID, S. (1976). Dynamic positioning using Kalman filtering and optimal control theory, IFAC/IFIP Symp. on Automation in Offshore Oil Field Operation, Holland, Amsterdam, pp. 183-186.

[3] BALCHEN, J.G., JENSSEN, N. A. SÆLID, S. (1980). Dynamic positioning of floating vessels based on Kalman filtering and optimal control, Proc. of the 19th IEEE Conf. on Decision and Control, Albuquerque, N.M., pp. 852-864.

[4] BALCHEN, J.G., JENSSEN, N.A. SÆLID, S. (1980). A dynamic positioning system based on Kalman filtering and optimal control, Modeling, Identification and Control, 1, pp. 135-163 doi:10.4173/mic.1980.3.1

[5] FALTINSEN, O.M., DAHLE, L. SORTLAND, B. (1986). Slowdrift damping and response of a moored ship in irregular waves, Proc.. 3rd OMAE conf, Tokyo, Japan.

[6] FALTINSEN, O.M. SORTLAND, B. (1987). Slow drift eddy making damping of a ship, Applied Ocean Research, 9,1, pp. 37-46 doi:10.1016/S0141-1187(87)80001-9

[7] FALTINSEN, O.M. (1990). Sea Loads on Ships and Offshore Structures, Cambridge University Press.

[8] FOSSEN, T.I. (1994). Guidance and Control of Ocean Vehicles, John Wiley and Sons Ltd.

[9] FOSSEN, T.I., SAGATUN, S.I. SØRENSEN, A.J. (1995). Identification of dynamically positioned ships, Proc. of the 3rd IFAC Workshop on Control Applications in Marine Systems.CAMS´95, Trondheim, Norway.

[10] FUNG, P. T-K. GRIMBLE, M. (1983). Dynamic ship positioning using self-tuning Kalman filter, IEEE Trans. on Automatic Control, AC-28, pp. 339-349 doi:10.1109/TAC.1983.1103226

[11] GRIMBLE, M.J., PATTON, R. J. WISE, D.A. (1980). The design of dynamic ship positioning control systems using stochastic optimal control theory, Optimal Control Applications and Methods, 1, pp. 167-202 doi:10.1002/oca.4660010207

[12] GRIMBLE, M.J., FATTON, R.J. WISE, D.A. (1980). Use of Kalman filtering techniques in dynamic ship positioning systems, IEE Proc., 127, D, pp. 93-102.

[13] ISHERWOOD, M.A. (1972). Wind resistance of merchant ships, Trans. Inst. Naval Arch., RINA. 115, pp. 327-338.

[14] NEWMAN, J.N. (1974). Second order slowly varying forces on vessels in irregular waves, Proc. Int. Symp. on the Dynamics of Marine Vehicles and Structures in Waves, London, England, Mechanical Engineering Publications Ltd. pp. 182-186.

[15] NEWMAN, J. N. (1977). Marine Hydrodynamics, MIT Press, Cambridge, Massachusetts.

[16] SAGATUN, S. I., SØRENSEN, A.J. FOSSEN. T.I. (1995). State estimation and dynamic positioning of marine vessels, The paper is submitted to the IEEE Trans. on control Systems Technology.1995.

[17] SALVESEN, N., TUCK, E.O. FALTINSEN, O.M. (1970). Ship motions and seal loads, Trans. SNAME, 78, pp. 250-287.

[18] SÆLID, S., JENSSEN, N.A. BALCHEN, J.G. (1983). Design and analysis of a dynamic positioning system based on Kalman filtering and optimal control, IEEE Transactions on Automatic Control, AC-28, pp. 331-339 doi:10.1109/TAC.1983.1103225

[19] WICHERS, J.E.W. (1993). Position control - from anchoring to DP system, New techniques for assessing and quantifying vessel stability and seakeeping qualities, University Enterprise Training Partnership. UETP, Marine Science and Technology Section 18. pp. 1-23.Trondheim, Norway.

**BibTeX:**

@article{MIC-1996-2-6,

title={{Design of a dynamic positioning system using model-based control}},

author={Sørensen, Asgeir J. and Sagatun, Svein I. and Fossen, Thor I.},

journal={Modeling, Identification and Control},

volume={17},

number={2},

pages={135--151},

year={1996},

doi={10.4173/mic.1996.2.6},

publisher={Norwegian Society of Automatic Control}

};