碩士 / 國立臺灣大學 / 工程科學及海洋工程學研究所 / 99 / The study describes a passive localization algorithm for a robotic fish by utilization of a transducer array attached on sides of body. Localization is performed in the water tank by measuring the signal from fixed sound sources to estimate the relative position of the robot with respect to the source. The algorithm requires synchronously receiving VHF array signal with large amount of data stream, a FPGA(Field Programmable Gate Array) processor is used to collect from high speed analog to digital converter synchronously. Generalized cross correlation technique is applied to estimate the time difference of arrival from signal transmitted directly and reflected by water surface and each set of array sensors. Piezometer is used for measuring the depth of the robot. In order to find position estimation errors function due to sensors noises, linearization of the localization algorithm equations is performed to derive the correlation matrix between position estimate errors and sensor errors. Assuming sensors errors are independent, the variance of position can be linearly superposed of sensors variances. It is shown in simulations and experiments that the system localization accuracy is limited by sensors noises, position values, and the lengths of array’s baselines.
| Identifer | oai:union.ndltd.org:TW/099NTU05345006 |
| Date | January 2010 |
| Creators | Ming-Yi Chien, 簡明毅 |
| Contributors | 郭振華 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | en_US |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 65 |
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