水下无人系统学报

Simulation on Small-Angle Water Entry Process of Torpedo

CHENG Wen-xin, CAI Wei-jun, YANG Chun-wu

2014, 22(3): 161-164. doi: 10.11993/j.issn.1673-1948.2014.03.001

[Abstract](1145) [PDF 729KB](783)

Abstract:
The multiphase mixture model and the dynamic mesh method are used to analyze the forming process of cav-ity in torpedo water entry with small angle, and the characteristics of interaction between torpedo shape and water entry cavity wall to achieve the change rules of pitch torque and torque action point for different water entry angle and water entry angle of attack. Simulations show that reducing angle of attack or delaying ignition can avoid such abnormal phe-nomena as engine′s stalling and torpedo′s broaching, and pump jet configuration facilitates stable water entry process of a torpedo.

Computing Reliability of Underwater Mobile Communication Network Based on Markov Chain Theory

LIANG Qing-wei, SUN Tian-yuan, JIANG Shan-shan

2014, 22(3): 165-168. doi: 10.11993/j.issn.1673-1948.2014.03.002

[Abstract](1181) [PDF 214KB](391)

Abstract:
With the development of underwater communication and sensor technology, the underwater mobile commu-nication network has been widely applied. Its reliability refers to the efficiency and quality of the information transmis-sion. This paper proposes a method for computing the reliability of the underwater mobile communication network based on Markov chain model. In this method, the states of the underwater mobile communication network are simplified and classified to get the probability matrix of the network′s stable state via modeling with Markov chain theory. Quantitative reliability is hence obtained through multiplying the probability matrix of a communication index′s reliability. Verifica-tion indicates that this method significantly reduces complexity of modeling, and can compute reliability of underwater mobile communication network with simplified operation.

Effect of Wedged Ring Connection Structure on Noise Radiation of Torpedo Shell

MA Rui-lei, YIN Shao-ping, CAO Xiao-juan, YAN Hai, QIN Xiao-hui

2014, 22(3): 169-173. doi: 10.11993/j.issn.1673-1948.2014.03.003

[Abstract](1109) [PDF 689KB](579)

Abstract:
Both finite element method and boundary element method are adopted to analyze the effect of the wedged ring connection structure on the noise radiation of torpedo shell. First, the finite element models for a torpedo are estab-lished, and then the accuracy of the models are verified through modal testing. Second, the models′ radiated sound power is calculated by using the boundary element method in the software LMS Virtual. Lab Acoustics. The curves of sound power for both models with and without wedged ring connection structure are compared, and the sound pressure level contours for typical frequency are obtained. The results indicate that the total sound power of the model with wedged ring structure is 10 dB lower than that of the one without wedged ring structure. This study may facilitate noise predic-tion and noise control of a torpedo.

Target Recognition Method Based on Distributed Modeling of Submarine

DONG Zhong-chen, LI Ya-an, LI Yang, LIU Wang-sheng

2014, 22(3): 174-178. doi: 10.11993/j.issn.1673-1948.2014.03.004

[Abstract](1080) [PDF 749KB](602)

Abstract:
A submarine target recognition method for a torpedo is proposed based on the distributed object modeling to distinguish submarine from acoustic decoy. On the basis of the modeling theory of distributed object, a distributed object model of submarine is established, and the distributed signal parameter estimator(DSPE) is applied to direction of arri-val(DOA) estimation of the submarine distributed model. Simulations are carried out by means of the plane array, and the 3D orientation spectrums of submarine echo are obtained. Simulation results show that the present method can ef-fectively identify submarine structure for correct torpedo attack against target.

Extended State Observer-Based Head-on Intercept Guidance Law for Anti-Torpedo Torpedo

YANG Hui-zhen

2014, 22(3): 179-183. doi: 10.11993/j.issn.1673-1948.2014.03.005

[Abstract](766) [PDF 271KB](445)

Abstract:
According to the equations of relative movement between anti-torpedo torpedo(ATT) and incoming torpedo, the head-on interception problem is described as an optimal control problem with finial angle constraint. Because the angular rate of line-of-sight is difficult to be obtained by homing system of ATT, an extended state observer is designed for estimating the angular rate and the value of uncertain disturbance caused by incoming torpedo maneuvering, and the control rudder angle can be calculated by solving the linear horizontal dynamical equations of ATT. Hence, the optimal guidance law with disturbance compensation is implemented. Simulation results show that the proposed optimal guid-ance law gains better head-on interception performance than the traditional proportion guidance law.

An Algorithm with Time-delay Difference for Underwater Acoustic Syn- chronous Positioning System Based on Non-equidistant Line Array

YANG Zhi-quan, SHANG Fan

2014, 22(3): 184-188. doi: 10.11993/j.issn.1673-1948.2014.03.006

[Abstract](1079) [PDF 411KB](447)

Abstract:
Underwater acoustic positioning system is a basic measurement system for underwater weapon test or under-water acoustic countermeasure mission. This paper presents a fast positioning method for designing underwater acous-tic synchronous positioning system for a torpedo based on horizontal non-equidistant line array positioning technology, correlation window corrected time-delay difference technology, etc., and introduces its principle and the real-time tra-jectory amendment method. Simulation with Matlab shows that this algorithm is feasible and correct. This non-equidis-tant line array positioning system has the advantages of flexible array deployment, and is economical and reliable, so it can be mounted on a wide range of array element carrier platforms. This study may provide a reference for designing torpedo’s underwater acoustic positioning systems with medium or long distance, and short or ultra-short baseline.

An Improved Scheme for Limited Feedback QOSTBC

HAN Chong, ZHANG Xiao-min, LI Tong-xu, CHEN Yu

2014, 22(3): 189-193. doi: 10.11993/j.issn.1673-1948.2014.03.007

[Abstract](837) [PDF 341KB](383)

Abstract:
The quasi orthogonal space-time block code(QOSTBC) scheme uses feedback channel to improve system performance. Because the increase in amount of feedback results in higher complexity, the space-time code loses its own advantage. In this paper, an improved limited feedback QOSTBC scheme is proposed based on the diagonalizti- on reconstruction of encoding matrix and the adequate rotation of equivalent sub-channels. Combining the theory of un- derwater acoustic channel model and the simulation analysis, it shows that the proposed scheme is significantly im-proved in such parameters as peak power ratio, computation complexity of real numbers multiplication and real numbers addition. In addition, the system complexity is reduced, the equivalent channel gain is increased, and the bit error rate of system is lowered. Simulation results demonstrate the effectiveness and reliability of the proposed scheme.

Torque Ripple Inhibition of Brushless DC Motor by DTC

WANG Song-lin, XIE Shun-yin, ZHANG Lin-sen

2014, 22(3): 194-199. doi: 10.11993/j.issn.1673-1948.2014.03.008

[Abstract](1156) [PDF 624KB](558)

Abstract:
To minimize torque ripple and improve dynamic performance of brushless DC motor(BLDCM), the direct torque control(DTC) is applied to the BLDCM drive system. Based on the analysis of the pulse width modulation(PWM) current control, this paper researches into the torque ripple inhibition with DTC method, where the torque ripple is pro-duced by both non-ideal back electromotive force (back-EMF) and current commutation. According to the characteristics of the BLDCM in two-phase conducting mode, a BLDCM-DTC drive system with and without stator flux control is established. Simulation and experimental results prove that the system makes effective control on torque and current, and gains better inhibition of torque ripple and faster dynamic response of the BLDCM, compared with conventional PWM current control.

Design of Single Layer Cylinder Sleeve under High Pressure for Torpedo Piston Engine

WAN Rong-hua, LI Xin, PENG Bo, YANG Yan

2014, 22(3): 200-203. doi: 10.11993/j.issn.1673-1948.2014.03.009

[Abstract](781) [PDF 477KB](528)

Abstract:
The software MSC.Patran and finite element method are employed to analyze the temperature and stress fields of different designs of cylinder sleeves for torpedo piston engine, hence a more reasonable scheme is determined. This scheme is applicable to the engine with the maximum gas pressure higher than 30 MPa, and the corresponding single layer cylinder sleeve is verified by the testing.

Main Factors Influencing Submarine-Borne Torpedo Hit Probability in Different Guidance Modes

CAO Qing-gang, TIAN Heng-dou, YANG Xu-sheng, FANG Yi

2014, 22(3): 204-209. doi: 10.11993/j.issn.1673-1948.2014.03.010

[Abstract](779) [PDF 347KB](502)

Abstract:
As an important index in submarine-borne torpedo weapon test, hit probability directly reflects the attack accuracy and operational effectiveness of torpedo weapon. Based on the basic theory of calculating torpedo hit probabil-ity, we establish some guidance models for different torpedo guidance modes. The main factors influencing the hit probability are analyzed through simulation and calculation to provide a theoretical reference for submarine-borne tor-pedo weapon test.

Combination Strategy of Guidance Methods for Wire-guided Torpedo

WEI Yu-hua, WANG Kai-shuai

2014, 22(3): 210-213. doi: 10.11993/j.issn.1673-1948.2014.03.011

[Abstract](1145) [PDF 174KB](623)

Abstract:
A wire-guided torpedo can not achieve its optimum operational efficiency in the case of single wire-guidance method. Considering the guidance purpose of every torpedo attacking phase, we propose a combination strategy of guidance methods for a wire-guided torpedo, and discuss the application occasion and condition of the combination strategy, as well as the requirements for target movement information and modeling. Simulation result validates the effi-ciency of the proposed combination strategy of torpedo wire-guidance methods. This study may provide a reference to the research on wire-guidance methods for attacking maneuvering target by a wire-guided torpedo.

Study on Salvo Method of Rocket Homing Depth Charges

ZHAO Dan-hui, HE Xin-yi, CHEN Zhao-feng, ZHU Bin

2014, 22(3): 214-220. doi: 10.11993/j.issn.1673-1948.2014.03.012

[Abstract](997) [PDF 678KB](639)

Abstract:
Taking Germany Seapike as an example, we establish a virtual trajectory model and a detecting model of a rocket homing depth charge based on the data from public reports and routine hypothesis, offer its salvo method, and compare the simulated hit probabilities of depth charge salvos with different number of depth charges. The results show that in typical conditions, 3 charges salvo could achieve the best cost-efficiency ratio, and higher hit probability of depth charge salvo can be obtained in the case of shorter target distance and larger maneuver.

A Method of Comprehensive Performance Evaluation for Torpedo Based on Variable Weight Model

YANG Li-juan, TIAN Zheng, ZHAO Wei, LI Fu-xiao, MA Xu-kun, LI Jie

2014, 22(3): 221-225. doi: 10.11993/j.issn.1673-1948.2014.03.013

[Abstract](1216) [PDF 257KB](581)

Abstract:
Based on the analyses of the relationship among torpedo subsystems as well as the relationship between the subsystems and the tactical and technical indexes, a step-by-step layered structure of torpedo′s comprehensive perform-ance indexes system is established. Making use of fuzzy theory, a method of comprehensive performance for torpedo based on the variable weight model is proposed. Firstly, sea trial data are nondimensionalized. And then the basic weight obtained by the analytic hierarchy process (AHP) is adjusted through the variable weight model. The quantitative as-sessment of torpedo′s comprehensive performance is achieved by using fuzzy theory. Simulation data analysis verifies the feasibility of the proposed method, and provides a reference for the acceptance sea trial.

A Test Method of Torpedo Cooperative Beacon Based on Virtual Instrument Technology

XIE Sheng, SHANG Fan, LIN Shao-xing

2014, 22(3): 226-229. doi: 10.11993/j.issn.1673-1948.2014.03.014

[Abstract](883) [PDF 453KB](550)

Abstract:
The existing torpedo cooperative beacon test instruments are designed based on discrete components, which results in complicated design, weak universality, and low efficiency. Therefore, a new test method based on virtual instrument is proposed in this paper. Data acquisition card is used as monitoring and control hardware, and the software LabVIEW is adopted by making full use of its strong functions of signal acquisition and in-strument control to realize integrated signal acquisition, processing, display and storage, etc. Applications of the testing system based on the proposed test method show its friend interface, easier operation and high accuracy, and the testing system meets the requirements of torpedo cooperative beacon test.

Research on Law of Sympathetic Detonation of Typical Charge Subjected to Underwater Explosion

LU Zhong-bao, HU Hong-wei, LIU Riu, YANG Fan

2014, 22(3): 230-235. doi: 10.11993/j.issn.1673-1948.2014.03.015

[Abstract](1317) [PDF 1224KB](619)

Abstract:
Aiming at typical charge in shell, a finite element analysis (FEA) model of sympathetic detonation of typical charge subjected to underwater explosion is established using the simulation software ANSYS/LS_DYNA. The distance of sympathetic detonation and the distance of safety are achieved by calculation, and a prototype ammunition is manu-factured for underwater sympathetic detonation experiment. The experimental result indicates that the FEA model can describe the underwater sympathetic detonation of charge in shell effectively, and that explosive pressure and bubble period can be used to estimate the occurrence of sympathetic detonation of acceptor charge. Based on the theoretical analysis of underwater sympathetic detonation, the warhead security of typical underwater weapon is estimated accord-ing to the experiment result. This study may give a reference for the safety design and the destroy ability evaluation of underwater weapon warhead.

Leakage Mechanism of Dynamite Ingredient in Explosives

MENG Xiang-yao, QIU Zhi-ming

2014, 22(3): 236-240. doi: 10.11993/j.issn.1673-1948.2014.03.016

[Abstract](807) [PDF 206KB](626)

Abstract:
The research on leakage mechanism of dynamite ingredient in explosives can support chemical trace detection technology. In this paper, the leakage principle of dynamite ingredient in explosives are theoretically analyzed according to the main chemical composition leaking out of explosives, the leakage ways to environment, and the micro leakage process of dissolution-diffusion-desorption in polymer materials; and a mathematical leakage model is built on the basis of Fick’s law. This theoretical research on the leakage principle of dynamite ingredient in explosives may effectively make up the inadequacy of experimental research, and promote the development of chemical detection of explosives.

2014 Vol. 22, No. 3

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