博士 / 國立成功大學 / 系統及船舶機電工程學系碩博士班 / 94 / A nonlinear mathematical model composed of seakeeping and maneuvering with six degrees of freedom of motions is built and the time domain simulation for ship motions in waves is calculated by the fourth Runge-Kutta method. Based on the equation of motions, the autopilot performances in waves are investigated by the PD controller and sliding mode controller. With the autopilot, the track keeping for the ship to the desired heading angle is achieved by the line-of-sight method. Furthermore, two kinds of controllers, i.e. the individual combined control and integrated control, based on the sliding mode control law are built to reduce the roll motion by the rudder control. The former considers sway-yaw motion and roll motion separately, and the other considers the coupling motions for sway-yaw-roll responses. In order to achieve optimal control performance, the genetic algorithms are adopted to obtain the optimal design parameters. Since the time domain simulation of irregular waves is time consuming, the optimal design parameters are simply determined based on the corresponding regular wave with maximum roll response which obtained from the sea state and response amplitude operator (RAO) of roll motion. From the comparison between simulations of turning circle and sea trial information, nonlinear maneuvering coefficients in the equations of motion indeed have significant effects on ship maneuvering ability and can not be neglected. The track keeping test reveals the control ability of sliding mode controller is better than PD one when external disturbances are considered. From a series of simulation results in regular waves, long-crested waves and short-crested waves, the track keeping function with the sliding mode controller are effective when the ship sails with high speed, and it can also achieve the roll reduction purpose by rudder control. However, if the ship velocity becomes lower, the roll reduction effect is invisible, but controller is still able to keep the track. According to the present results we find the mathematical model developed here is useful for estimating the ship maneuvering ability in waves at initial ship design phase and can also play a very important real time simulation tool while applying the visual reality technique to ship simulators.
| Identifer | oai:union.ndltd.org:TW/094NCKU5345008 |
| Date | January 2006 |
| Creators | Jhih-Hong Luo, 羅志宏 |
| Contributors | Ming-Ling Lee, Ming-Chung Fang, 李銘霖, 方銘川 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 155 |
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