水下无人系统学报

Investigation into the Damage Effect of Anti-Torpedo Torpedo

LIU Xiao-ou, YIN Shao-ping, GAO Shan

2008, 16(3): 001-5. doi: 10.11993/j.issn.1673-1948.2008.03.001

[Abstract](1933) [PDF 602KB](690)

Abstract:
It is very important to research the structural dynamic response of torpedo under the shock of underwater explosion and the damage radius of anti-torpedo torpedo (ATT) for the development of ATT. Based on the finite element analysis software MSC. Dytran, models of the torpedo attacked by ATT, ATT explosive, and water area were presented, and simulations were conducted. Therefore, the courses of shock wave propagation and dynamic response on topedo due to blast of ATT′s explosive were achieved, and the effects of different explosion distances and different water pressures on torpedo were also analyzed. According to the current ship damage standards in the world and the simulation results, damage radii evaluations and different types of damage rules of the torpedo attacked by ATT were obtained.

Numerical Simulation of Water-entry Impact Force for Air-launched Mine

SONG Bao-wei, DU Xiao-xu, MENG Rui, LI Jia-wang, SHAO Cheng

2008, 16(3): 006-8. doi: 10.11993/j.issn.1673-1948.2008.03.002

[Abstract](2245) [PDF 405KB](909)

Abstract:
Based on the unsteady potential flow theory of incompressible liquid, a model of water-entry impact force for air-launched mine was presented, and the water-entry impact force was calculated. Simulation results show that the water-entry impact force is huge, the maximal impact force increases with the water-entry velocity and is directly proportional to the square of water-entry velocity, the maximal axial impact force increases with the water-entry angle, and the maximal normal impact force decreases with the water-entry angle.

Intercept Trajectory and Intercept Probability of Anti-Torpedo Torpedo

LI Xiao-ning, MING Xing, ZHU Ruo-han

2008, 16(3): 009-12. doi: 10.11993/j.issn.1673-1948.2008.03.003

[Abstract](2045) [PDF 426KB](665)

Abstract:
Based on the analysis of two intercept trajectories of anti-torpedo torpedo(ATT), mathematical models of converse trajectory and direct trajectory were established. The relationship between the azimuth of incoming torpedo and the launching angle of ATT was discussed. The influence of ship′s course and distance measurement error of incoming torpedo on the intercept probability of ATT was simulated and calculated by Monte-Carlo method. The relation between the intercept trajectory and the performance of ATT was also discussed. Simulation results indicate that converse trajectory has a higher intercept probability. Accurate positioning of the incoming torpedo can effectively improve the intercept probability of ATT. And increasing homing detection distance and search sector angle can also enhance the intercept probability of ATT.

Recoverable Display System for Sail Test Mine

GU Jun, She Hu-qing

2008, 16(3): 013-16. doi: 10.11993/j.issn.1673-1948.2008.03.004

[Abstract](1375) [PDF 539KB](583)

Abstract:
The technical and tactical performances of explosive mine can be sufficiently verified by adopting sail test mine as a model in the process of mine development, and continually improved through sea trials. Recoverable display technology is important to the test mine. This paper introduces the importance of recoverable display system and the current recoverable modes of sail test mine, and presents a new recoverable display system technology, including the components and function, the working process and mechanism, based on the requirement of the test mine. Finally, we summarize some technological innovations, such as recovering negative buoyancy sail test mine by throwing mine head weight under deep water, searching conveniently and locating accurately the mine by using several display modes. The trial results show that the technology can improve the system reliability.

Assisted Navigation Hardware-in-Loop Simulation System of Autonomous Undersea Vehicle Based on GPS Satellite Simulator

WANG Yan-kai, KANG Feng-ju, DUAN Shi-mei, WANG Jiao-yan, WEI Wei

2008, 16(3): 017-21. doi: 10.11993/j.issn.1673-1948.2008.03.005

[Abstract](2205) [PDF 667KB](796)

Abstract:
Global position system(GPS) can revise the cumulative error of dead reckoning navigation system, such as strapdown inertial navigation system(SINS) and Doppler navigation, with its ability of accurate navigation and positioning when it is applied to the navigation system of autonomous underwater vehicle(AUV). We designed a satellite assisted navigation simulation system for AUV, which consists of a satellite positioned GPS satellite simulator, a GPS receiver, and a simulation computer. The hardware interface design and software development of the hardware-in-oop simulation system are discussed in this paper. The simulation result shows that the navigation platform is reliable, and our scheme can be applied successfully to the hardware-in-loop simulation system of AUV navigation and control.

Analysis of Initial State Control Problem and Solution for Torpedo Control System

LIU Xue-chen, XU Feng, LI Xu-dong

2008, 16(3): 022-24. doi: 10.11993/j.issn.1673-1948.2008.03.006

[Abstract](1511) [PDF 343KB](635)

Abstract:
In the process of debugging some certain torpedoes, a unstable initial state of important signal was found, which causes the components of control system unreliable. Based on the analysis of the torpedo circuitry, the fault was discovered due to unstable charged state of 54F373 latch. Two methods were accordingly presented to eliminate the fault. Finally, the scheme " reset chip + pull-up resistor" was selected through a large number of tests considering the alterability of product state and operational reliability. The result shows that the initial state control problem in torpedo control system has been completely solved.

Steering Vector Reconstruction Method for DOA Estimation of Coherent Signal

ZHUO Jie, SUN Chao, YANG Yi-xin

2008, 16(3): 025-28. doi: 10.11993/j.issn.1673-1948.2008.03.007

[Abstract](2123) [PDF 449KB](1128)

Abstract:
An effective method is proposed for recovering coherent signals impinging on a uniform linear array and estimating their directions of arrival (DOAs). The spatial signature is blindly estimated from the eigen-decomposition of the covariance matrix, where the steering vectors to all coherent signals are reconstructed directly by using the property of sub-array shift-invariance. When used as the array weighting, the steering vectors will provide recovered signals in corresponding beams. DOAs can be estimated from the angular spectrum subsequently. Results from the real data analysis are in good agreement with theoretical analysis. Our method not only can resolve closely spaced coherent signals, but also is shown to be more robust to system errors compared to some other DOA estimation algorithms.

Study on Slotted Cymbal Transducer

TIAN Feng-hua, LV Lin-xia, QIAN Jian-ping

2008, 16(3): 029-32. doi: 10.11993/j.issn.1673-1948.2008.03.008

[Abstract](1938) [PDF 460KB](721)

Abstract:
Flexural motion of the Cymbal transducer end caps causes high tangential stress, which lead to loss of mechanical output energy. However, radially slotted end caps can release the tangential stress, increase the efficiency of energy transform, decrease the fundamental resonance frequencies, extend axial shift, and enhance voltage receiving sensitivity. This paper studied the influences of slots’ position, number, width and depth on mechanical, electric and electromechanical characteristics of a Cymbal transducer with finite element method(FEM) and ANSYS software. A slotted Cymbal transducer was developed and tested. The test result was in good agreement with the calculated one. Therefore, slotted Cymbal transducer needs to be further researched, and can be expected for wide application.

A New Method of Passive Homing Feature Extraction Based on Target Moving Information

REN Rui-dong, ZHANG Qun-fei, HUANG Jian-guo

2008, 16(3): 033-36. doi: 10.11993/j.issn.1673-1948.2008.03.009

[Abstract](1903) [PDF 439KB](650)

Abstract:
Low frequency passive homing is an effective measure of improving torpedo acceptance range. However, its weak interference suppression is a main bottleneck in application of passive homing system. Power spectrum extraction is the main feature extraction method at present, but power spectrum feature is easy to be simulated with the development of countermeasure. We propose a novel feature extraction method based on target moving information for target recognition of passive homing. This new method makes use of the distances between intersections of directional lines gotten at different positions to judge weather target is moving or not. The principle of this method is introduced and the performance is analyzed. Simulation results show that the method is effective in distinguishing moving targets and static ones, and can therefore resist the disturbance of floating decoy to improve counter-countermeasure ability of passive homing.

Adaptive Nulling Beamforming of Concentric-Ring Arrays

WANG Kun-peng, LIANG Hong, HU Xu-juan

2008, 16(3): 037-39. doi: 10.11993/j.issn.1673-1948.2008.03.010

[Abstract](1673) [PDF 346KB](1465)

Abstract:
Based on the analysis of the beampattern of a circular array, a concentric-ring array is proposed to solve the problem of higher sidelobe level of the circular array. This paper applies two robust adaptive nulling beamforming algorithms, the eigenspace-based beamformer (ESB) and the multiple constrained minimum variance beamformer (MCMVB), to the concentric-ring arrays, and gets deeper nulling. Simulation results show that the beampattern of the concentric-ring array has lower sidelobe level compared with the circular array, and is effective in formation of adaptive nulling as well.

Numerical Simulation on Turbulent Flow in Rotary Combustion Chamber for HAP Tri-propellant of Thermal Torpedo

ZHAO Wei-bing, QIAN Zhi-bo, HE Chang-fu, MA Wei-feng

2008, 16(3): 040-44. doi: 10.11993/j.issn.1673-1948.2008.03.011

[Abstract](1631) [PDF 624KB](692)

Abstract:
On the basis of the characteristics and working process of HAP tri-propellant in torpedo rotary combustion chamber, mathematical models for the turbulent two-phase flow and combustion process were established. The initial and boundary conditions were investigated and set accordingly. Numerical simulations were conducted by using the software FLUENT, and the distributions of flow fields within the combustion chamber under different regimes were obtained. The results indicate that the turbulent flow and blending process is enhanced and the reverse flow moves to center and head areas. The fuel vaporization, blending, diffusion and heat transfer during combustion process as well as combustion are enhanced, and combustion process becomes much more uniform and steady. Therefore, the combustion efficiency can be improved and the size of rotary combustion chamber could be smaller than the fixed combustion chamber.

Technological Advantages and Application Limitations of Wake Homing Torpedo

LUO Di, LI Ben-chang, LI Yuan

2008, 16(3): 045-48. doi: 10.11993/j.issn.1673-1948.2008.03.012

[Abstract](2000) [PDF 531KB](722)

Abstract:
Aiming at the diversification of function system and homing modes in the development of submarine-launched torpedo, this paper analyses the advantages in operational application of wake homing torpedo based on its mechanism, such as stronger counter-countermeasure, higher speed, and higher target acquisition probability for selected target. It also analyses the limitations in tactics, such as limited attacking speed and the types of attackable targets, greater loss in torpedo range, difficult combination with wire-guidance, and inaccurate attack on moving targets. Moreover, this paper suggests that homing mode be rationally configured and selected according to mission and tactical requirement of submarine when development and operational application of torpedo weapon are planned.

Two-Torpedo Salvo Method for Helicopter Hovering Attack

LIN Zong-xiang, ZHOU Ming, MEN Jin-zhu

2008, 16(3): 049-51. doi: 10.11993/j.issn.1673-1948.2008.03.013

[Abstract](1754) [PDF 324KB](726)

Abstract:
Aiming at the current status that helicopter uses single torpedo to attack submarine, a method of two torpedoes salvo for helicopter hovering attack is presented. We establish a model of torpedo hit probability under pure evasive maneuver situation by analyzing the organization of search area of two torpedoes salvo, possible target position area, selection of salvo aiming point, and the submarine evasive maneuver model.Compared to single torpedo attack, the simulation result shows that two torpedoes salvo can improve target detecting probability and has a larger detecting distance under the same condition. Furthermore, the method achieves higher torpedo hit probability under large board angle than the single torpedo attack.

An Integrated Guidance Law Based on Fuzzy Control for Wire-guidance Torpedo

SONG Ming-yu

2008, 16(3): 052-56. doi: 10.11993/j.issn.1673-1948.2008.03.014

[Abstract](1784) [PDF 564KB](606)

Abstract:
Combining the advantages of azimuth guidance method and predicted point guidance method, an integrated guidance method for wire-guidance torpedo is presented. By introducing fuzzy control, the parameters of the integrated guidance method can be adaptively adjusted according to the information of target movement and the distance between torpedo and target. Thus the torpedo can be effectively guided to the position with ideal entering distance and angle for wake homing. Simulation results show the method can guide torpedo to the target wake with required entering angle and good trajectory .

Traceability of Special Test Equipments

XUE Ming-juan, ZHANG Long, PENG Shu-ya

2008, 16(3): 057-59. doi: 10.11993/j.issn.1673-1948.2008.03.015

[Abstract](1263) [PDF 355KB](582)

Abstract:
Special test equipments play an important role in performance test and evaluation of military products. The quality of the products is greatly affected by the measurement data of the special test equipments. And the accuracy of measurement of the special test equipments is an important factor in product test. This paper discusses the importance of the equipments in calibration traceability chain, introduces normal calibration methods, and proposes some suggestions about standardizing test methods and unitizing criterions.

2008 Vol. 16, No. 3

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