| Project/Area Number |
01460166
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
船舶構造・建造
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| Research Institution | Kyusyu University |
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Principal Investigator |
OHTAKA Katuo Kyushu University, Faculty of Eng'g, Professor, 工学部, 教授 (80194182)
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| Co-Investigator(Kenkyū-buntansha) |
MAEDA Masahiro Kyushu Univ, . Faculty of Eng'g, Research Assistant, 工学部, 助手 (70173713)
YASUZAWA Yukitaka Kyushu Univ, . Faculty of Eng'g, Associate Prof., 工学部, 助教授 (10191123)
福地 信義 九州大学, 工学部, 教授 (80039677)
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| Project Period (FY) |
1989 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥6,200,000 (Direct Cost: ¥6,200,000)
Fiscal Year 1991: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1990: ¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1989: ¥3,400,000 (Direct Cost: ¥3,400,000)
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| Keywords | Ship Vibration / Active Control / Superstructure / 能動制振 / フィ-ドバック制御 / 最適レギュレ-タ |
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| Research Abstract |
A. General formulae for the modal control of flat plate have been made, by means of which at first vibratory characteristics of one-degree-of-freedom system are calculated when it is controlled by hydraulic servomechanism. Feedback signal is taken either vibratory displacement, velocity or acceleration. The results show the typical characteristics in each case.
B. Next the vibratory characteristics of the system with several modes are examined by means of the optimal control the eory, and the following results are obtained.
(1) When two-mode system are controlled by one input force, two system poles are moving leftwards of complex plane as the weighting factors for response is increasing, and at last one of the poles fall on the real axis, which means the behavior corresponding to this pole has no vibratory nature, while another pole settles asymptotically to a certain point. If the point is near the imaginary axis, system shows slowly-decaying transient response. This case occurs if natural frequencies of two component modes are near. In case of control by two input forces, however, we can make both of poles located sufficiently far from imaginary axis.
(2) When we intend to control some specified modes only, it is necessary to include all the modes who se natural frequencies are very near to the specified modes.
C. Tendon control of superstructure vibration in ships is investigated by means of the optimal control theory as mentioned above. The general tendency is nearly the same as the flat plate mentioned above. As a numerical example the control of propeller-excited superstructure vibration are examined on a 60, 000tdw tanker. When the exciting force is IOKN, it is necessary to add 30KN of control force in tendon to clear the ISO vibration criterion.
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