Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)最新文献

{"title":"Simulation of cogging in a 100 kW permanent magnet octagonal linear generator for ocean wave conversion","authors":"Irina Ivanova, Olov Ågren, H. Bernhoff, M. Leijon","doi":"10.1109/UT.2004.1405602","DOIUrl":"https://doi.org/10.1109/UT.2004.1405602","url":null,"abstract":"Fluctuations in the torque acting on the rotor in a rotating electric generator i.e., cogging, gives unstable rotor motion and can venture reliable operation of the machine. Cogging also gives a similar fluctuation in the output power. This paper presents a study of the cogging force in a linear permanent magnet generator. A constant output power is possible in a rotating machine with three phases winding. In a linear generator, due to the reciprocate piston motion, power fluctuations on the slow time scale of the piston bounce period cannot be avoided. Associated with power variations on a time scale shorter than the piston bounce motion is fluctuations on the force (torque) acting on the piston, i.e., cogging. Cogging is not less dangerous in linear generators compared to rotation machines and the problem requires investigation. The paper investigates means to reduce cogging by improving the geometrical design of the stator. In particular, rational number of the slots per pole and phase reduce the cogging by one order of magnitude","PeriodicalId":437450,"journal":{"name":"Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123134889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Acoustic inversions from an explosive source of opportunity in the ASIAEX2001-SCS experiment","authors":"Ying-Tsong Lin, Chi-Fang Chen, J. Lynch, N. Chotiros, A. Newhall, A. Turgut, S. Schock, C. Chiu","doi":"10.1109/UT.2004.1405566","DOIUrl":"https://doi.org/10.1109/UT.2004.1405566","url":null,"abstract":"Acoustic inversions including source localization and geoacoustic inversion from an unexpected explosion in the ASIAEX2001-SCS experiment is presented. Horizontal beamforming is performed to find the source azimuthal direction and the water wave part of the modal dispersion curve is used to find the source range. The relation of the source depth and the charge weight has been obtained from the bubble pulse period. The localization result shows that the detonation occurred in the direction of east-north east and about 30 km distant from the receiver. To perform the bottom inverse, we use a broadband linear inverse technique employing the modal group velocity, which is inferred from the modal arrival time and source range. In the end, a four-layered bottom model is created, which is consistent with both our explosion data and independent source tow data. The resolution and variance of the estimate are also presented. In conclusion, this bottom model should be widely applicable for modeling broadband sound propagation in the ASIAEX2001-SCS experiment site.","PeriodicalId":437450,"journal":{"name":"Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125096869","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Adaptive learning to environment using Self-Organizing Map and its application for underwater vehicles","authors":"S. Nishida, K. Ishii, T. Ura","doi":"10.1109/UT.2004.1405552","DOIUrl":"https://doi.org/10.1109/UT.2004.1405552","url":null,"abstract":"Autonomous underwater vehicles (AUVs) have great advantages for activities in deep sea, and expected as the attractive tool. However, AUVs have various problems which should be solved. In this paper, the Self-Organizing Map (SOM) is applied as the clustering method for the navigation system. The SOM is known as one of the effective methods to extract the principle feature from many parameters and decrease the dimension of parameters. Through the competitive learning algorithms, the obtained map is tuned to express specific features of the input signals. We have been investigating the possibility of navigation system based on SOM through simulations are experiments with an AUV called \"Twin-Burger\". The learning algorithm of usual SOM is unsupervised learning. However, supervised learning algorithms should be introduced because the relationship between distances information and desirable behavior of the robot, that is, the relationship from inputs to outputs should be acquired and learned. In this paper, a supervised learning algorithm is introduced into SOM and a method to adapt the local map to its environment by learning and evaluating the trajectory of robot is proposed. In the proposed method, the \"initial map\" is made static and digital value as teaching data. In order to include more information of environment in the initial map, the trajectories of robot are evaluated, and the evaluation is utilized in the learning process. This method enables the map to have both the effect of dynamics of robot and environmental information. The efficiency of the method is investigated through the simulations and experiments.","PeriodicalId":437450,"journal":{"name":"Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129219176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental land model of tele-operated underwater backhoe with AR technology","authors":"H. Taketsugu, Y. Takashi, A. Junichi, I. Masaki, Y. Hiroaki","doi":"10.1109/UT.2004.1405600","DOIUrl":"https://doi.org/10.1109/UT.2004.1405600","url":null,"abstract":"Teleoperation technology of hydraulic general-purpose machinery was developed for land applications, particularly at disaster recovery sites. The technology level was significantly improved through practical application at disaster sites such as the Mt. Unzen-fugendake eruption in 1994 and the Usu volcano eruption in 2000. On the other hand, underwater work in harbors largely depends on divers because the scale of work is smaller and manual work is generally more appropriate. Another reason is that the special environments can lead to technological difficulties. Underwater work by divers, however, may be inefficient depending on oceanographic phenomena such as poor visibility and strong tidal currents, and it may also be unsafe because of the difficulty in perceiving and avoiding danger. In addition, long hours of underwater work can lead to a heavy physical load caused by the hydraulic pressure, placing greater demands on the worker than when working on land. In order to solve these issues, we propose the use of Augmented Reality technology for the teleoperation of underwater equipment. Using a laboratory model, we conducted controlled experiments and investigations on the reflection-force sensor mechanism. For the interface section, we fabricated a figure input unit similar in relationship to the front part of a backhoe, and conducted experiments to confirm the operational efficiency of its pointing action. This paper describes the development of an experimental land-based machine","PeriodicalId":437450,"journal":{"name":"Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121257317","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A practical method for simulating pectoral fin locomotion of a biomimetic autonomous underwater vehicle","authors":"F. Chiu, Chi-Kang Chen, Jenhwa Guo","doi":"10.1109/UT.2004.1405593","DOIUrl":"https://doi.org/10.1109/UT.2004.1405593","url":null,"abstract":"In this paper, a practical method to simulate pectoral fin locomotion of a fishlike AUV testbed is presented. Basing on a blade element synthesis scheme, the authors developed a simple mathematical model to evaluate the hydrodynamic forces acting on a pectoral fin in feathering motion and lead-lag motion. The pectoral fin is treated as a number of moving blade element, the lift, cross flow drag and added inertia acting on each blade element are evaluated as a two dimensional oscillating thin foil and they are described in the fin-fixed coordinate system. These forces of blade element are transferred to the fuselage-fixed coordinate system and then integrated to obtain the total forces acting on a pectoral fin. Kato's data from model test and calculation on a pectoral fin of a bass are cited to compare with the corresponding calculation results by the present simple mathematical model. The quite satisfactory agreement confirmed the validity of the simple model for evaluating the hydrodynamic forces of a pectoral fin. On this base, the previously developed computer program for simulating body-tail undulatory locomotion is then extended to simulate the pectoral fin locomotion of a biomimetic autonomous underwater vehicle","PeriodicalId":437450,"journal":{"name":"Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114318297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An improved Wigner distribution based algorithm for signal identification","authors":"Fu-Sheng Lu, Cheng Yang, Pai-Ling Lin","doi":"10.1109/UT.2004.1405469","DOIUrl":"https://doi.org/10.1109/UT.2004.1405469","url":null,"abstract":"A new modified Wigner distribution, in which the cumbersome cross-terms can be totally eliminated, is combined with the wavelet packet decomposition to get a better time-frequency analysis algorithm. The non-stationary signal are first decomposed into approximation and detail signals by the wavelet packet analysis, and then each constituent signal is analyzed by the modified distribution to get a time-frequency representation data matrix. To simplify the computation for identification, the Karhunen-Loe/spl grave/ve transform is used to find the principal eigenvector of the distribution data matrix. The principal eigenvectors of the approximation and detail signals construct the signal feature database for identification. In addition to numerical simulations, experiments of some underwater acoustic signal identification are conducted.","PeriodicalId":437450,"journal":{"name":"Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129380746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Buried object detection with Synthetic Aperture Sonar","authors":"Y. Nakamura, I. Yamaguchi, T. Tanaka, Y. Hama","doi":"10.1109/UT.2004.1405462","DOIUrl":"https://doi.org/10.1109/UT.2004.1405462","url":null,"abstract":"This work presents the experimental results of buried objects detection with a prototype Low Frequency Synthetic Aperture Sonar (LF-SAS). The experiment was carried out to ensure motion compensation algorithm and to study the availability of target detection both on the seabed and in the sediments. The experimental system mainly consists of tow-fish and control equipment. The tow-fish has a transducer array which can transmit and receive around 7 kHz acoustic signal, and the control equipment controls the tow-fish and records the received signals. Data processing, which includes synthetic aperture beamformer and motion compensation, is carried out on a PC. The experimental results clearly show that the combination of low frequency acoustics and synthetic aperture processing with motion compensation is effective to detect mine-like targets on and under the seabed.","PeriodicalId":437450,"journal":{"name":"Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133761325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distance measurement technology development at remotely teleoperated robotic manipulator system for underwater constructions","authors":"Chung Cheng Chang, Chia Yuan Chang, Yu-Ting Cheng","doi":"10.1109/UT.2004.1405598","DOIUrl":"https://doi.org/10.1109/UT.2004.1405598","url":null,"abstract":"To promote underwater construction, the tools such as underwater robotic manipulator system, underwater vehicles and so on are necessary. Furthermore, these system need an accurate 3D position parameters. If no position information for automatic control system that system is difficult to be operated. Hence, it is important to take position information. Although 3D position camera can offer 3D position parameters, it has still some deviation. In addition, the manipulator system need accurate distance information for fast and accurate operation. Hence, an accurate distance measurement system is necessary for a remotely teleoperated robotic manipulator system for underwater constructions. This paper focus on the distance measurement study to offer a accurate target distance information. The information can combine with 3D position camera to obtain more accurate 3D position parameters to offer a useful position information for underwater constructions, with a remotely teleoperated robotic manipulator system. In this paper, three distance measurement system, includes commercial ultrasonic distance measurement system, fabricated ultrasonic system and a laser distance measurement system is study. The commercial distance measurement system have a distance measurement system rang 8~35 cm, plusmn0.1 cm. However, a short distance measurement is difficult to be measured with the measurement system. On the other side, the fabricated measurement system can measure a short distance. Information from 0~5 cm, accuracy plusmn0.3 cm. The fabricated distance measurement system fabricated with PZT thin film. In this study, a horn is added to improve the accuracy of distance measurement. In addition, the laser distance measurement system, measurement system is used to measure the distance information also in this study. The combination of these distance measurement system to form a multiple range distance measurement can offer a long measurement range for accurate distance measurement underwater. A detailed experiment is to be studied in the future. Furthermore, the distance measurement system has been offered a distance measurement in a remotely teleoperated robotic manipulator system for underwater constructions","PeriodicalId":437450,"journal":{"name":"Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116414934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Target strength pattern measurements of Antarctic krill (Euphausia superba) by split-beam method in a small tank","authors":"K. Amakasu, M. Furusawa","doi":"10.1109/UT.2004.1405515","DOIUrl":"https://doi.org/10.1109/UT.2004.1405515","url":null,"abstract":"Target strength (TS) measurements were conducted for Antarctic krill (Euphausia superba) at 70 kHz on board RTV Umitaka-maru of Tokyo University of Marine Science and Technology in February 2003 during the Southern Ocean survey and TS patterns of 12 live Antarctic krill were successfully measured. We used a new precise method using the split-beam method in a small tank for TS measurement of small-size animals. We compared the measured results with the theoretical TS patterns by the Distorted Wave Born Approximation-based deformed cylinder model (DWBA model) and confirmed a good agreement at near the main lobe, however, the measured results were higher than the model predictions in the side lobe regions. Although the discrepancy was examined from several aspects such as body bending and scattering from pleopods, any factor was not decisive. In other words, it is likely that the discrepancy is caused by some factors combined. The stochastic version of the DWBA model showed a reasonable agreement with the measured TS in the side lobe regions. This phenomenon should be examined further from physical view points.","PeriodicalId":437450,"journal":{"name":"Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129323249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Implementation of an acoustic data bus","authors":"K. R. Nair, G. Varkey","doi":"10.1109/UT.2004.1405474","DOIUrl":"https://doi.org/10.1109/UT.2004.1405474","url":null,"abstract":"Advancement in the field of signal processing in the past several decades has resulted in noise ranging being recognized as an important condition-monitoring requirement for naval vessels. It can provide valuable information pertinent to its maintenance and combat-worthiness. In its most basic form, an underwater noise range (UWNR) consists of a number of fixed seabed hydrophones arranged to detect the sound radiated from a passing surface ship of submarine. The received signal is transmitted along a communication medium (underwater cables/microwave link/etc.) to a suitable portable or land-based analysis and recording equipment. At the shore end, the signal is subjected to a preliminary on-line and a detailed off-line exploratory analysis. The purpose of the first is to determine the \"good-ness\" of the run and to decide on modification of the \"run-schedules\". The purpose of the latter is to perform a detailed examination of the signals and compare it with similar observations collected earlier from the same vessel or different vessels. These analysis results may be considered as the information output of the system - the recorded signals being the data outputs. Noise ranging is an activity requiring a detailed planning, many months in advance. The available time of the vessel on the range has to be utilized in the most optimum fashion. This necessitates a detailed online analysis of the acoustic signal originating from various parts of the ship over a wide frequency range. An acoustic data bus (ADB) over which the analysis machines could be connected is an ideal architecture to facilitate such an analysis. This work presents the structure, design and implementation aspects of such a system based on a set of DSP boards interconnected in a copper TAXI set-up. In the system under implementation, the acoustic signals are digitized close to the sensor. This reduces further noise contamination, thus allowing an SNR of 186 dB. The digitized signals from various sensors are sent to an underwater junction box where they are multiplexed and converted in the optical domain. This multiplexed stream is transported over FO cables to a data handling system (DHS) at shore. DHS performs the optical to electrical conversion and presents the signal stream to a pair of DSPs. The DSPs act as the hub of the ADB. It demultiplexes the signals into various channels and attaches headers to it. The header contains environmental parameters like air and water pressure and DGPS tracking information, needed to determine the extent of the various corrections (range, Doppler, etc.) to the signal spectrum. The DSPs at DHS are connected to a set of acoustic analysis computers (AAC) using individual copper TAXI lines. This arrangement permits a sustained data rate of 20 MBPS and distances of a few hundreds of meters between DHS and AACs. Each AAC contains a complementary DSP board that receives the signal from the DHS and performs various signal processing functions. The AAC can s","PeriodicalId":437450,"journal":{"name":"Proceedings of the 2004 International Symposium on Underwater Technology (IEEE Cat. No.04EX869)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130555680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}