2005 Fiscal Year Final Research Report Summary
A study on a marine autopilot with the function of roll dumping for a small boat
| Project/Area Number |
16560705
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Naval and maritime engineering
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| Research Institution | Toyama National College of Maritime Technology |
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Principal Investigator |
NAKATANI Toshihiko Toyama National College of Maritime Technology, Dept.of Maritime Technology, Associate Professor, 商船学科, 助教授 (30249776)
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| Co-Investigator(Kenkyū-buntansha) |
ENDO Makoto Toyama National College of Maritime Technology, Dept.of Maritime Technology, Professor, 商船学科, 教授 (40149919)
YAMAMOTO Keiichiro Toyama National College of Maritime Technology, Dept.of Maritime Technology, Lecturer, 商船学科, 講師 (40321418)
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| Project Period (FY) |
2004 – 2005
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| Keywords | autopilot / rudder roll stabilize / statistical analysis / noise contribution / AR model / AIC / optimal control |
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| Research Abstract |
A ship is equipped with an autopilot system to keep the ship's course constant. However, when operating in rough seas, since the course fluctuates considerably because of the roll motion caused by sea conditions, it must be helped very much to have a comfortable navigation if fluctuations of both of the course and the roll can be reduced at a time by controlling the rudder. There are few cases analyzing the relationship between a course-keeping system and the roll motion quantitatively on a small boat.
Firstly, the navigational system was upgraded and the experiment was carried out so that a random white noise signal was added to the rudder order signal to identify system dynamics. In order to analyze experimental data, a Multi-variate Auto Regressive (MAR) model was fitted to the recorded data using the minimum AIC estimate procedure. From the estimated MAR model, useful tools for the statistical analysis, such as a power spectrum, noise contribution and so on, could be obtained. As a result of the analysis, it was made clear that fluctuation of the roll was strongly influenced by the rudder.
Secondly, a new controller was designed, based on the information obtained from the analysis. This is a new type of autopilot which orders a control signal to the steering gear taking the roll motion into consideration. The new autopilot was designed using a modern control theory under a quadratic performance function with various weighting coefficients. Digital simulations were executed to evaluate the designed controller in order to make certain that the new type of autopilot functioned as designed. As a result of simulations, the new system had good performance compared with the original data.
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Research Products
(7 results)
