| Summary: | 碩士 === 國立成功大學 === 系統及船舶機電工程學系 === 102 === Control law design for marine surface vessels (MSV) is one of the crucial ocean technologies to the current ship industry. A well-controlled marine surface vessel must possess accurate trajectory or waypoint tracking capability and excellent robustness with respect to ocean disturbances such as ocean current, wave, and wind induced forces and torques, for being sure to achieve given sailing missions. For these mentioned reasons, two novel nonlinear control laws for the tracking design problems of marine surface vessels are presented in this thesis. These two approaches based on H2 and H∞ control concepts can be effectively applied to generate control commands on marine surface vessels operating in sailing regimes where the effectiveness of ocean environmental disturbances are random and unpredictable. Design objectives are to specify two control laws that analytically satisfy the H2 and H∞ performances, for the nonlinear control designs of marine surface vessels. In general, it is hard to obtain the closed-form solutions from these two nonlinear tracking problems. Fortunately, because of the adequate choice of state variable transformations, the nonlinear H2 and H∞ tracking problems of the marine surface vessels can be converted to two solvable nonlinear time-varying Riccati-like equations. Furthermore, two closed-form solutions to these two Riccati-like equations can be obtained with very simple and easy to implement structures.
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