碩士 / 國立臺灣大學 / 工程科學與海洋工程學系 / 91 / We present a fishlike Biomimetic Autonomous Underwater Vehicle (BAUV). The BAUV is segmented into five components: head, tail, tail fin, and two side fins. The head segment and the tail fin are rigid. The body part between the head and the tail fin, the tail, is supported by a rigid center-link, and a flexible outer body. There are six brushless DC servomotors mounted inside the BAUV. A Doppler sonar is set in the abdominal part of the BAUV for sensing the direction, velocity, and water depth. Four of the motors responsible for the motion of side fins, two motors responsible for the tail joint and the tail fin joint. The BAUV is equipped with a point sonar on the head for the measurement of environmental features. Because the BAUV has precise hovering and agile motion capability, we design a control system to perform maneuvering, precise localization and map-building simultaneously. The BAUV placed at an unknown location in an unknown environment has the ability to localize itself using only relative observations of the environment and then to use the environment simultaneously to navigate. A Bayesian-based method using the extended Kalman filter that combines vehicle localization and environmental mapping is implemented. We also use a gated nearest neighbor strategy to perform the data association which initialize the new features, manage existent map features, and delete out-of-date features. Furthermore, in order to decrease the way-points’ positional uncertainty, an optimal measurement strategy is used. This strategy is to select the optimal measurement provided by one out of many directions at each time. The problem is then transformed into a nonlinear two-point boundary value problem. The optimal policy is to maintain the accuracy of the predicted states and to approach minimal cost by solving the optimal control problem. Computer simulations and tank experiment results are provided finally to demonstrate the effectiveness of our method.
Key Words: Underwater Vehicles, Biomimetic, Localization
| Identifer | oai:union.ndltd.org:TW/091NTU00345050 |
| Date | January 2003 |
| Creators | PoChen Shih, 施博晟 |
| Contributors | Jenhwa Guo, 郭振華 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 87 |
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