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Fig.8 Thruster movements
Fig.9 |
Thrust commands from route tracking controller and actual thrust calculated by feedback signals of thrusters |
broken line:reference, solid line:feedback
This simulation result shows that the controller is an effective in a multiple waypoint tracking mission. Incidentally, this simulation could finish to calculate in about 155 seconds on the PC with Intel Pentium III 600MHz in spite of two optimum calculations: the ship positioning controller and the optimal thrust allocation controller.
5. CONCLUSION
We have been developed the system that apply the optimum thrust allocation problem and the ship positioning control problem of azimuth thruster, which have a redundancy, to the RH control system. In the ship positioning control, we formulate fixed time terminal constraint problems to relieve sudden changes of manipulated variables, which are occurred in turning after passing Waypoints. Also, we simulate a constant-speed tracking system for plural Waypoints by combining a optimum thrust allocation controller with a ship positioning controller and verify the effectiveness of our ship maneuvering control system.
ACKNOWLEGEMENT
We would like to thank Dr. Toshiyuki Ohtsuka at OSAKA University for his useful discussions on RH control.
REFERENCES
[1] H.Fukuda, Kouhei.Ohtsu, T.Okazaki, T.Tasaki, N.Fukui The Development of A Simplified Ship's Guidance System with Tracking Control", The Journal of Institute of Navigation, Vol.103, pp.41-49, 2000
[2] T.Ohtsuka "Real-Time Optimization Technique for Nonlinear Optimal Feedback Control", J. of the Society of Instrument and Control Engineers, 36, 11, pp.776-783, 1997
[3] T.Ohtsuka "Continuation/GMRES Method for Fast Algorithm of Nonlinear Receding Horizon Control", Proceedings of the 39th IEEE Conference on Decision and Control, pp.766-771, 2000
[4] K.karasuno, K.Maekawa, S.Okano, J.Miyoshi "A Component-type Mathematical Model of Hydrodynamic Forces in Steering Motion Derived form a Simplified Vortex Model (5) -Modification of midship part's vortex system due to turning motion -", J. of Society of Naval Architects of Japan, Vol.190, pp.169-180, 2001.
[5] Y.Kohno, M.Hamamatsu, Y.Saito, H.Ikeda "Development of Dynamic Positioning System", KAWASAKI TECHNICAL REVIEW, Vol.147, pp.30-33, 2001
[6] H.Yamaura "Introduction to Optimal Control" CORONA PUBLISHING, CO., LTD., 1996
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