水下无人系统学报

Optimization Design of Perpendicular Hit Terminal Trajectory for Lightweight Antisubmarine Torpedo

NIE Wei-dong, GAO Zhi-yong, LIU Yan-bo

2012, 20(1): 001-8. doi: 10.11993/j.issn.1673-1948.2012.01.001

[Abstract](1404) [PDF 362KB](614)

Abstract:
Although it is more theoretically perfect and compendious than other guidance laws, the optimal perpendicular hit terminal guidance law based on Pontryagin′s minimal principle is more difficult to be applied directly to lightweight antisubmarine torpedo trajectory design for its idealization and indeterminate control coefficients. Accordingly, a practical optimization method is introduced into perpendicular hit terminal trajectory design for a lightweight antisubmarine torpedo in this paper. In this method, engineering-oriented secondary optimization is performed on the guidance law mentioned above to gain optimal guidance laws for different initial operation postures. Digital simulations demonstrate the feasibility and reliability of the proposed method. In addition, the design sensitivity of the terminal trajectory optimization system is analyzed, and suggestions about the optimization design are offered.

Numerical Computation and Analysis on Hydrodynamic Characteristics of Different Profiles of Flapping Foil

PAN Guang, ZHONG Ru-yi, SONG Bao-wei, CAO Yong-hui

2012, 20(1): 009-13. doi: 10.11993/j.issn.1673-1948.2012.01.002

[Abstract](1220) [PDF 365KB](659)

Abstract:
This paper mainly addresses the thrust and lift characteristics of underwater symmetrical flapping foils by using the numerical computation method, analyzes the hydrodynamic of the flapping foils with different Strouhal num-bers, and summarizes the influences of the profile parameters and related factors on the flapping foils′ propulsive effect. The results show that the maximal thrust coefficient, the average thrust coefficient and the maximal lift coefficient de-crease linearly with increasing ratio of motion center to chord length; the parameters of profiles and the working condi-tions have different effects on the thrust and lift characteristics of the foils.

Finite Element Analysis for Torpedo Seawater Pipe Based on HyperMesh and Nastran

BAI Kun-xue, YIN Shao-ping

2012, 20(1): 014-18. doi: 10.11993/j.issn.1673-1948.2012.01.003

[Abstract](1313) [PDF 279KB](972)

Abstract:
To identify modal parameters of a seawater pipe and find out frequency bands of resonance, a process covering three-dimensional modeling, meshing, and finite element analysis is established by using the softwares UG, HyperMesh, and Msc.Nastran. Furthermore, the first 8 orders of natural frequencies and vibration modes are obtained according to the free mo-dal analysis of the seawater pipe. Simulation results show that the first 8 orders of natural frequencies are mainly in low-frequency range, and the bellows are the target of vibration control of seawater pipeline because they possess the most variation of vibration amplitude. This process is also verified to be high in efficiency and precision.

Multiple-Frequency Estimation Method with Undersampled Waveform

GAO Yu-bing, LIANG Hong, DU Jin-xiang

2012, 20(1): 019-23. doi: 10.11993/j.issn.1673-1948.2012.01.004

[Abstract](940) [PDF 208KB](593)

Abstract:
In some applications, such as signal processing and radar systems, it is preferred that the range of the fre-quencies is as large as possible for a given sampling rate and the sampling rate is below the Nyquist rate. In both cases, frequencies estimation from undersampled waveforms is necessary. In this paper, a generalized robust Chinese remain-der theorem (GRCRT) for reconstructing multiple positive real numbers is presented, where modules are not pair-wisely co-prime and the remainders with errors. In theorem 1, the sufficient condition for the multiple real numbers to satisfy is given, where all remainders have errors and we can determine which one in the remainder set is the remainder of any real number. And an approach to determine unique solution of multiple real numbers from the remainder set with errors is proposed in theorem 2. Simulation results show that the present method is efficient for estimating multiple frequencies from multiple undersampled waveforms with sampling rate below the Nyquist rate, and it can be applied to such areas as digital signal processing.

Discussion about Anti-active Sonar Torpedo Based on Combined Guidance Way

QIAN Zhong-ming

2012, 20(1): 024-27. doi: 10.11993/j.issn.1673-1948.2012.01.005

[Abstract](1294) [PDF 158KB](628)

Abstract:
Guidance of submarine- launched anti-ship torpedo is influenced by sea environment, which restricts the submarine attacking distance and the torpedo homing distance. As a result, the author makes use of the design con- cep-tion of anti-radiation missile to present a new combined guidance based on target detection and other guidance ways. The anti-active sonar torpedo adopting the proposed combined guidance takes active sonar pulse signals from anti-submarine ship and torpedo as its guiding source in attacking target. In addition, the design principle and charac- teristics of the anti-active sonar torpedo with the combined guidance are addressed, and its operation process is supposed. The analysis shows that the anti-active sonar torpedo with the proposed combined guidance meets the requirements for actual attack.

Active Measurement of Torpedo Missdistance Based on Electromagnetic Fuze

CHEN Guang, HUANG Xiao-yi, PAN Lan-qiang

2012, 20(1): 028-32. doi: 10.11993/j.issn.1673-1948.2012.01.006

[Abstract](1430) [PDF 254KB](656)

Abstract:
Torpedo missdistance is usually measured via passive ranging methods with inconvenient operation, compli-cated solution model and low measuring precision. In this paper, an active measuring method of torpedo missdistance is put forward based on electromagnetic fuze. The ranging principle of electromagnetic fuze is analyzed, the solution model of phase characteristic and missdistance is set up, and the numerical solution process of missdistance is given. In addition, a tank experiment is conducted. The measured data indicate that the absolute ranging precision is less than 0.02 m, and the relative ranging precision is less than 2.5% when the distance from transmitting/receiving antennas to target (steel plate) is within 0.8~1.5 m, which demonstrates high measuring precision and simple implementation of the pro-posed method.

Laser Wake Signal Feature Extraction Based on Wavelet Package Energy Feature

GUO Hu-sheng, LIU Qi-zhong, LIU Jin-long

2012, 20(1): 033-37. doi: 10.11993/j.issn.1673-1948.2012.01.007

[Abstract](1098) [PDF 378KB](586)

Abstract:
For detection and recognition of the laser wake of a surface ship, a novel method for detecting the wake backscattering signal by making use of the wavelet package energy feature vector is presented. An adaptive noise can-celler based on variable forgivable factor is designed to filter the backscattering signal and system noise, so as to effec-tively select the target signal. The wave package energy feature vector is extracted by using wavelet package decompo-sition method and different energy formation of frequency range. The dimension of the feature vector is reduced with the principal components analysis method. Experimental results show that the proposed method can effectively recognize the features of different wake backscattering signals of a surface ship.

Correcting Localization Error with a Single Beacon for AUV

ZHANG Fu-bin, ZHANG Yong-qing

2012, 20(1): 038-41. doi: 10.11993/j.issn.1673-1948.2012.01.008

[Abstract](915) [PDF 277KB](615)

Abstract:
The localization error of an AUV′s integrated navigation positioning system, which is composed of strapdown inertial navigation system (SINS), Doppler velocity logger (DVL) and depth sensor, increases with time, and the hidden performance of the AUV will decrease in correcting the error via GPS. In this paper, a new method is proposed to correct the localization error of the AUV’s navigation system by adopting a fixed beacon under water. In this method, the principle of acoustic ranging is used to measure the distance between AUV and beacon, then the real-time position of the AUV is calculated according to spacial geometric relationships, and the localization error of the AUV′s navigation system is corrected by Kalman filter. Simulation results show that the present approach can correct AUV′s localization error effectively, which infers an application value in engineering.

Dynamic Model of Unmanned Underwater Vehicle Based on BTT Control

ZHANG Yi-chao, ZHOU Xu-chang, SHEN Jian-sen, SHI Han-cheng

2012, 20(1): 042-46. doi: 10.11993/j.issn.1673-1948.2012.01.009

[Abstract](1552) [PDF 224KB](551)

Abstract:
The stability of traditional unmanned underwater vehicle (UUV) is deteriorated because of the induced rolling moment generated by skid and the cross-coupling among three autopilot channels in high-speed maneuver, so a bank-to-turn (BTT) control method is proposed to improve UUV maneuverability. Appropriate simplification of the spacial dynamic model of UUV is made according to the characters of the UUV navigation dynamic model and BTT control, hence a BTT control-based UUV dynamic model is obtained. Moreover, the normal overload are taken as state variables, which can be measured easily, in order to simplify the design of the autopilot. The proposed model may be suitable for the design of the UUV control system based on BTT control technology.

Design of Control Law for Torpedo Rolling under Large Maneuvering Motion

ZHANG Qin-nan, SONG Xi-fa, Lü Rui, LIN Long-yan

2012, 20(1): 047-50. doi: 10.11993/j.issn.1673-1948.2012.01.010

[Abstract](1137) [PDF 131KB](506)

Abstract:
Severe dynamic coupling is inevitable in rolling channel of torpedo during large maneuvering motion. In order to reduce the influence of coupling on rolling channel, this paper proposes a solution by combining model-reference adaptive control and variable structure control. The variable structure control law is used to handle the coupling which is regarded as interference, and the model-reference adaptive control law is used to improve dynamic performance of the system. Simulation results show that the control law can solve the coupling in rolling channel effectively under large maneuvering motion to avoid the deficient control accuracy of the traditional control methods.

A Direct Torque Control System of Counter-rotating PMSM for Torpedo Propulsion

XU Hai-zhu, XIE Shun-yi, LIAN Jun-qiang, WANG Ding

2012, 20(1): 051-55. doi: 10.11993/j.issn.1673-1948.2012.01.011

[Abstract](1355) [PDF 367KB](690)

Abstract:
To improve the torque density and efficiency of a torpedo motor, the configuration and working principle of a counter-rotating permanent magnet synchronous motor(PMSM) are introduced. A simulation model of counter-rotating PMSM is established by deducing its mathematical model, and the design principle of this kind of motor is analyzed. A new direct torque control system for counter-rotating PMSM is designed, and the speed following strategy of two rotors in disturbance condition is proposed to keep the speeds of two rotors equal. Simulation result, which coincides well with the theoretical analysis, verifies that direct torque control is competent for regulating speed of counter-rotating PMSM with high robustness and quick torque response.

Effect of Rotor Shroud on Flow Passage Performance of Torpedo Turbine

YI Jin-bao, ZHAO Wei-bing, SHI Hai-chao

2012, 20(1): 056-59. doi: 10.11993/j.issn.1673-1948.2012.01.012

[Abstract](1376) [PDF 391KB](561)

Abstract:
Aiming at the heavy flow leakage loss from rotor tip because of short blade in a torpedo turbine, a three- di-mensional, viscous and steady computational fluid dynamics (CFD) analysis is performed for studying the turbine flow field and performance of rotors with or without rotor shroud under different designing condition by solving Rans-Navier-Stokes equations. The changing trends of turbine′s power, efficiency, gas flow rate, and various flow losses with or without rotor shroud are achieved, and the effect of rotor shroud on the flow field and the performance of turbine are analyzed. Results show that the rotor shroud can clearly enhance the power, efficiency and performance of turbine by eliminating the leakage flow and vortex at rotor tip, and by reducing the inner flow loss of torpedo turbine.

Measurement Method of Mobile Acoustic Decoy Receiving Distance for Sea Trial

CUI Bao-he, ZHENG Yuan

2012, 20(1): 060-62. doi: 10.11993/j.issn.1673-1948.2012.01.013

[Abstract](1662) [PDF 295KB](598)

Abstract:
For the difference between sea trial environment and ideal environment in the process of weapon test and evaluation, a measurement method of environmental parameters is proposed with focus on seabed inversion method for calculating seabed parameters in large area, and on converting scheme of receiving distance by considering mobile acoustic decoy′s characteristics. Moreover, a smooth-averaged sound field model is established to calculate the receiving distance of a mobile acoustic decoy for sea trial. This study may provide a reference for equipment acceptance test.

Design and Implementation of Hardware-in-the-loop Simulation Environment in Scaling Multi-Target and Multi-Jamming of Torpedo

ZHAO Gang, YUE Qing

2012, 20(1): 063-68. doi: 10.11993/j.issn.1673-1948.2012.01.014

[Abstract](1506) [PDF 388KB](532)

Abstract:
The underwater scaling multi-target identification has become an important index for evaluating acoustic countermeasure capability of modern torpedo homing system, but the relative sea trial circumstance is difficult to con-struct. Based on the analyses of target validity judgment and shelter calculation for scaling multi-target, a real-time sig-nal generation algorithm is designed, and a hardware-in-the-loop simulation system is constructed. Simulation of scaling multi-target and multi-jamming environment is conducted with the system. The test results prove that the proposed sys-tem can meet the needs of relational simulation.

Simulation and Experimentation on the Similarity Law of Warhead for Destroying Underwater Target

LU Zhong-bao, NAN Chang-jiang, BU Xiang-dong

2012, 20(1): 069-73. doi: 10.11993/j.issn.1673-1948.2012.01.015

[Abstract](1654) [PDF 373KB](616)

Abstract:
To learn if damage effect of a scale-down torpedo warhead can be used to predict that of a prototype warhead for destroying underwater target, based on the similarity theory, some models are established with same scales in war-head size, testing distance of shock wave, and distance of target plate. The shock wave pressure and target plate strain are calculated and compared by simulation and underwater explosion experiment. The calculation and experiment results coincide well, and the deviations of corresponding shock wave pressure and target plate strain of the models are very small, which indicates that the scale-down models following the similarity law can accurately predict the destroy char-acteristics of the prototype warhead against underwater target. This study may provide a basis for the power evaluation of underwater warhead.

Perspective of the Technologies about Torpedo Warhead

GUO Tao, WU Ya-jun

2012, 20(1): 074-77. doi: 10.11993/j.issn.1673-1948.2012.01.016

[Abstract](1881) [PDF 177KB](791)

Abstract:
In view of the present situation of the technologies about torpedo warhead, five aspects in the research of ex-plosive effect enhancement of torpedo warhead are prospected. 1) developing new type of torpedo warhead structure to realize shape charge explosion; 2) developing new type of high energy explosive to enhance damage power; 3) enlarging torpedo diameter to substantially increase the maximum charge; 4) adopting advanced technology to increase charge density; and 5) using nuclear charge if necessary. Moreover, it is suggested that more attention should be paid to nu-merical simulation and underwater explosion test of torpedo warhead on the basis of improving research methods and supporting conditions.

Analysis on Power of Underwater Acoustic Interfere Munitions

SUN Zhong-fu, SHENG Zhen-xin, LIU Rong-zhong, GUO Rui

2012, 20(1): 078-80. doi: 10.11993/j.issn.1673-1948.2012.01.017

[Abstract](1030) [PDF 252KB](629)

Abstract:
To study the effects of shell thickness and material on power of underwater acoustic interfere munitions by AUTODYN software, based on the Cole′s underwater explosion empirical formula, the sound pressure level of shock wave created by underwater explosion of TNT with a metal shell is calculated for different thickness and material of the shell. Rela-tions among the sound pressure level of shock wave, the shell thickness and the shell material are analyzed. Simulation results show that the sound pressure level of shock wave increases first and then decreases with the thickness; and the higher the yield stress of shell material, the higher the sound pressure level of shock wave.

2012 Vol. 20, No. 1

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