水下无人系统学报

Drag Reduction Characteristics of New Groove Surface with Different Groove Sizes Distribution

SONG Bao-wei, LI Lei, HU Hai-bao, LIU Zhan-yi

2009, 17(4): 001-5. doi: 10.11993/j.issn.1673-1948.2009.04.001

[Abstract](1407) [PDF 626KB](787)

Abstract:
For the new V-groove surface with different groove sizes distribution, the drag reduction characteristic of turbulent boundary layer is studied. According to the particularity of the new groove shape, the computation region, grids and flow parameters are dealt with reasonably during the numerical simulation. The flow in turbulent boundary layer and the viscous drag over the groove surface are numerically simulated using the N-S formula and RNG  k-ε turbulence model. Compared with popular simple size groove surface and smooth surface, better drag reduction characteristics can be achieved on the new groove surface with a maximum drag reduction almost 15%. The new groove structure is in favor of second vortex formation and development, which fundamentally resulting in the drag reduction.

Discussion about Vibration Test of Airborne Torpedo Accessories

ZHANG Zhi-min, TIAN Shu-hong, CAO Xiao-juan, ZENG Xiao-fan

2009, 17(4): 006-9. doi: 10.11993/j.issn.1673-1948.2009.04.003

[Abstract](1336) [PDF 487KB](593)

Abstract:
Several technical issues during vibration environment test of airborne torpedo accessories are discussed. The selection of vibration environment test condition is introduced, and the root mean square(RMS) calculation of random vibration level is analyzed. Taking jig design of airborne torpedo accessories as example, the design principle of jig is presented. Some technical details during vibration test are explained. Compared with conventional vibration test, the proposed test includes the vibration response monitoring of airborne torpedo accessories, which facilitates to the selection of test method and solving of technical problems in the vibration test.

Key Technologies about Complete Trajectory Simulation for High Altitude Long-range Gliding Torpedo

PAN Guang, WU Wen-hui, MAO Zhao-yong, HUANG Qiao-gao

2009, 17(4): 010-15. doi: 10.11993/j.issn.1673-1948.2009.04.002

[Abstract](1626) [PDF 692KB](613)

Abstract:
The technology of high altitude long-range gliding torpedo(HALGT) is an integration of high altitude gliding and underwater voyage technologies. The simulation of the complete trajectory of HALGT is an important part and theoretical basis for conceptual design. In this paper, the complete trajectory of a HALGT is divided into several parts according to the leading factors during whole movement, and the main feature is analysed. The technology of trajectory simulation is studied. Modeling and simulation methods are presented on the basis of relative studies. These simulation methods may benefit the research of complete trajectory.

Multidisciplinary Robust Design Optimization of Micro Autonomous Underwater Vehicle

WANG Peng, SONG Bao-wei, LIU Xu-lin, MAO Zhao-yong

2009, 17(4): 016-19. doi: 10.11993/j.issn.1673-1948.2009.04.004

[Abstract](1677) [PDF 402KB](639)

Abstract:
Aiming at the inherent uncertainty and multidisciplinary in the design process of micro autonomous underwater vehicle (micro AUV), we combine the uncertainty design theory with the multidisciplinary design optimization theory to provide a robust collaborative optimization (RCO) method for large-scale and complex systems multidisciplinary robust design optimization (MRDO). In the end, an MRDO example of micro AUV using RCO method is given.

Scaling Target Echo Modeling Technology Based on Modified Highlight Model

LIU Wen-yuan, ZHANG Jing-yuan, LV Yang, LIU Xi-xia

2009, 17(4): 020-24. doi: 10.11993/j.issn.1673-1948.2009.04.005

[Abstract](2312) [PDF 510KB](1222)

Abstract:
In the near field, when a target does not move along the line, the velocity of each highlight is no longer equal to the velocity of the geometry center of the underwater target. Aiming at this problem, a typical resolving method for the highlight velocity of the moving target is presented, and hence a modified highlight model is built. Effects of torpedo-target distance, board angle of target, target speed and rotary angle speed on the echo spectrum are computed. Echo spectrum of the modified model is widened evidently, and the widening phenomenon is influenced mostly by target speed and rotary angle speed. Simulation results indicate that the proposed model can simulate the echo characteristic of underwater target more closely, and the model is feasible.

Analysis on Characteristics and Identification of Underwater Targets

WU Kai-ming, DING Cui-huan, WU Li-xin, REN Yun

2009, 17(4): 025-30. doi: 10.11993/j.issn.1673-1948.2009.04.006

[Abstract](2036) [PDF 768KB](845)

Abstract:
According to the whole systematic procedure of underwater target identification, we analyze the targets′ inherent and external characteristics that can be used for identification, and discuss the target-related aspects of oceanic acoustic field and dynamic oceanic environment field. Also, several identifying methods and their combinations are described. Moreover, applications of underwater targets characteristics in sonar design, simulation and detection are prospected. Comprehensive study of the underwater targets characteristics will give a scientific impetus to the development of oceanic acoustics and other related intersectional subjects.

Combination-Correlator Technology for Improving Detection Capability of Multi-Highlight Targets

YANG Bao-feng, DONG Chun-kai

2009, 17(4): 031-37. doi: 10.11993/j.issn.1673-1948.2009.04.007

[Abstract](1983) [PDF 643KB](652)

Abstract:
Addressing the problems in detecting weak echo targets by torpedo homing system , we analyze the working principle of time domain compression repetition correlator. By adopting the correlator, process gain and highlight parameter estimation precision are improved by accumulating and multiplying multi-highlight information. Double-channel time domain compression repetition and echo combination-multiplier technology and double-channel time domain compression repetition and echo combination-correlator technology are proposed, and corresponding theoretical analysis and simulation are performed. Simulation results indicate that the two technologies can raise 3 dB process gain compared with the time domain compression repetition correlator, and the estimation precision of highlight parameters is also improved. The validity and practicality of the proposed methods are verified by real-running test of torpedo.

Method of Narrowband Signal Blind Deconvolution Based on Array Model

WANG Cong, WANG Hai-yan, BAI Jun

2009, 17(4): 038-42. doi: 10.11993/j.issn.1673-1948.2009.04.008

[Abstract](1391) [PDF 503KB](620)

Abstract:
In marine engineering technology, when targets are detected by a torpedo, we need to separate and locate the signals of targets. The signals that the torpedo sensor-array receives are always convolution mixture ones. Considering only the narrowband signal in the pure time-delayed convolution mixture, we combine blind separation with array signal processing, and transform real number convolution mixture to complex number instantaneous mixture. Therefore, based on array model of blind separation, we complete the blind deconvolution via complex number blind separation. Simulation results prove that the method is efficient, and the signals of multi-target source from sine signal deconvolution facilitate the feature identification and localization of multi-target.

Discussion on Condition of Torpedo Active Homing Concealed Signal

WU Ya-jun, GUO Tao, LEI Xiao-li

2009, 17(4): 043-47. doi: 10.11993/j.issn.1673-1948.2009.04.009

[Abstract](2103) [PDF 582KB](689)

Abstract:
The development of torpedo homing technology with low probability of intercept (LPI) will become an important trend. This paper introduces the concept of radar LPI into torpedo homing system, and lays emphasis on the conditions required for torpedo to get active homing concealed signal based on the analysis of importance and methods of designing homing waveform. The overall design ideas of active homing concealed signal and classification of the signal forms are put forward, and several common LPT signals are provided. This study may provide a reference both for the further research on methods of generating and detecting active concealed signal and for the feasibility study of application of concealed signal to torpedo homing in order to improve combat effectiveness of torpedo.

Bandwidth Influence of Three-Axis Motion Table on Dynamic Performance of Torpedo Control System

XU Feng, HUANG Hua-hong, LIU Xue-chun

2009, 17(4): 048-52. doi: 10.11993/j.issn.1673-1948.2009.04.010

[Abstract](1676) [PDF 503KB](623)

Abstract:
A mathematical model of three-axis motion table is established, and the relation between controller parameter of the three-axis motion table and motion table bandwidth is determined. Taking MK46 torpedo self-oscillating system as an example, a digital simulation is conducted with MATLAB/Simulink by inserting the three-axis motion table model into the closed circuit of torpedo rolling channel to understand the influence of bandwidth of three-axis motion table on dynamic performance of torpedo control system. Simulation result shows that when the bandwidth of three-axis motion table is below the frequency of oscillating signal, the oscillation period becomes longer, the amplitude increases, and the stability of hardware-in-the-loop simulation system may even influenced. There is no influence of the three-axis motion table with 8 Hz bandwidth on those slowly changed signals with the time constants of controlling system larger than 0.6 s. The result could be regarded as a technical basis for the result analysis of hardware-in-the-loop simulations of torpedo control, the comparison of sea trial data, and the determination of dynamic performance indexes to research or purchase new type of three-axis motion table.

Accuracy Assessment Method of Fall Points for Autonomous Underwater Vehicle

LIU Ming-yong, ZHAO Chun-yang, ZHAO Tao

2009, 17(4): 053-56. doi: 10.11993/j.issn.1673-1948.2009.04.011

[Abstract](1772) [PDF 479KB](656)

Abstract:
Addressing the difficulty to organize extensive entire run trial in accuracy assessment of fall points for autonomous underwater vehicle (AUV), a sequential assessment method is proposed under the trajectory transform of AUV, and the influence of the error of trajectory transform on the risks of producer and consumer is also analyzed. By using this method, the accuracy of fall points can be assessed without entire run test, and the testing cost is reduced. Simulation result shows that the proposed method is feasible and brief with good value of engineering application.

Implementation of Distributed Virtual Simulation System for Multi-AUV Based on Simulink and VRML

ZHONG Yong-chao

2009, 17(4): 057-60. doi: 10.11993/j.issn.1673-1948.2009.04.012

[Abstract](2046) [PDF 530KB](631)

Abstract:
Aiming at the issues of poor risk, high cost and long period in sea trial of multi-autonomous underwater vehicle (multi-AUV), we establish an integrated distributed virtual simulation system based on MATLAB, develop a TCP/IP network interface by S-function of Simulink, create a virtual three-dimensional model of AUV, a sea world model, and a subsea terrain model by VRML, and implement the visual simulation of AUV using virtual reality toolbox to provide an effective simulation platform for multi-AUV. Simulation results show that this system can display the movement of multi-AUV realistically in a local area network, and test the validity of cooperation strategy of multi-AUV. This system is reliable and easy to extend, and may offer a reference for further research of multi-AUV.

YI Jin-bao, QIAN Jian-ping, DONG Chun-peng, ZU Zhi-hong, LI Liu-cheng, ZHAO Wei-bing, SHI Hai-chao

2009, 17(4): 061-66. doi: 10.11993/j.issn.1673-1948.2009.04.013

[Abstract](1633) [PDF 849KB](624)

Abstract:
A three-dimensional, viscous, steady CFD analysis is performed to investigate turbine flow field and performance of underwater vehicle by solving RANS-Navier-Stocks equations and RNG turbulence model. The flow detail and loss in turbine are studied for on-design and off-design conditions. The effect factor on turbine efficiency under off-design condition is analyzed. The results show that shock wave and flow separation occur in turbine under on-design condition, flow losses are caused by clearance flow in turbine. The turbine performance is degraded rapidly due to higher flow loss in nozzle as the back pressure increases under off-design condition. The predicted turbine efficiency agrees well with the test data.

Torpedo Turbine Control under Variable Conditions

MENG Ling-xiu, WANG Yu-cai, WANG Ying

2009, 17(4): 067-69. doi: 10.11993/j.issn.1673-1948.2009.04.014

[Abstract](1630) [PDF 375KB](700)

Abstract:
As a torpedo runs at variable conditions, such as variable-speed or variable-depth, the change of turbine′s main running parameters will lead to the variation of other running parameters, resulting in low efficiency or even abnormal running of the turbine. To keep high efficiency and working stability under variable conditions, turbine power system must be regulated correspondingly. Therefore, a turbine power model is built in this paper, and the adjustable parameters for variable conditions in the model are analyzed. A control method of simultaneously regulating propellant flow and nozzle number is adopted, and the regulation of nozzle number is optimized. The feasibility of the method is validated by the simulation results.

Launching Noise Reduction for Underwater Weapon Launch Tube

CHENG Guang-tao, ZHANG Zhen-shan

2009, 17(4): 070-73. doi: 10.11993/j.issn.1673-1948.2009.04.015

[Abstract](1699) [PDF 527KB](626)

Abstract:
We illustrate the importance of noise reduction of underwater weapon launch tube, and summarize the classification of underwater launch tube and the main sources of launching noise. The mechanism of launching noise is analyzed in view of equipment alteration and upgrade based on the current status of domestic weapon launcher and the characteristics of the tube driven by reciprocating pump. A series of methods to reduce launching noise is proposed in low noise design of underwater weapon launcher for the purposes of upgrading the existing launch tubes and designing new launchers.

Multispeed Application of Wire-guided Torpedo

LI Ben-chang, LIU He, GUO Qing

2009, 17(4): 074-76. doi: 10.11993/j.issn.1673-1948.2009.04.016

[Abstract](1782) [PDF 377KB](637)

Abstract:
According to tactical requirements of operational application for torpedo weapon and technical conditions of guidance and control for wire-guided torpedo, we analyze the influence of torpedo′s radiation noise and velocity on the operational application, and discuss the importance and necessity of adopting multispeed for a wire-guided torpedo. Simulation shows that if the advantage of torpedo velocity can not be taken effectively, huge limitation still exists in torpedo′s operational application in spite of the multispeed. In order to improve the tactical efficiency of the wire-guided torpedo with multispeed, the torpedo launch platform should offer some different guidance methods, so that the torpedo may take shorter time to approach the target with high speed, and keep lower radiation noise to make better use of the sonar detection with low speed. In addition, we indicate some problems to be solved in application of the alternative high or low velocity guidance method.

est Design of Operational Applicability for Torpedo Based on Bayes SPRT Method

GAO Jiang, LI Chun-feng, LIU Bo

2009, 17(4): 077-80. doi: 10.11993/j.issn.1673-1948.2009.04.017

[Abstract](1254) [PDF 394KB](593)

Abstract:
For the operational test evaluation of modern torpedo, we discuss the significance of the test of operational applicability for torpedo, describe the way to design the test of operational applicability for torpedo by using Bayes sequential probability ratio test(SPRT), and illustrate the selection of the test sample. By introducing Wald′s SPRT into Bayes SPRT method, we determine a test scheme quantitatively, and present a Bayes cut-off SPRT scheme under different pre-test probabilities. This test design method may offer a reference for the research on the test of operational applicability for modern weapons on sea range.

2009 Vol. 17, No. 4

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