水下无人系统学报

Simulation on Hydrodynamics of Supercavitation Vehicle

ZOU Qi-ming, WANG Gai-di, ZHANG Xi-jian, GUO Xiao-hui

2008, 16(4): 001-4. doi: 10.11993/j.issn.1673-1948.2008.04.001

[Abstract](2025) [PDF 448KB](780)

Abstract:
The major partial surfaces of supercavitation vehicle are wrapped by the bubbles of supercavitation, which forms a new hydrodynamic distribution as the vehicle running in water. Therefore, the vehicle′s motion mode is fully different from conventional one with complicated force state and nonlinear hydrodynamic force. To analyze the force characteristics of the vehicle, it is necessary to linearize the planing force and cavity lift. This paper describes the shape of cavity, discusses the major parameters affecting cavity shape, analyzes and linearizes the planing force and cavity lift. Simulation results show that the forces are linear within a certain scope. The motion characteristics of the vehicle can be analyzed further by using these linearized forces.

Novel Evaluation Model of Torpedo Test

ZHOU Chun-Ming

2008, 16(4): 005-9. doi: 10.11993/j.issn.1673-1948.2008.04.002

[Abstract](1489) [PDF 500KB](727)

Abstract:
To objectively evaluate the performance, quality and reliability of a torpedo, based on fuzzy mathematics, a new comprehensive evaluation method for torpedo test is presented and a corresponding evaluation model is established by analyzing the features of torpedo test and the existing evaluation methods. The present method expands the finite state of test result evaluation to infinite state, and describes the state with qualified level, thus updates evaluation method and technology of torpedo test result.

Numerical Simulation of Double-Layer Plate Structure Destroyed by Underwater Contact Explosion

Wu Ya-jun, ZHOU Peng, LEI Xiao-li

2008, 16(4): 010-14. doi: 10.11993/j.issn.1673-1948.2008.04.003

[Abstract](1721) [PDF 584KB](770)

Abstract:
Because the experiment of underwater explosion is not easy to perform, numerical simulation of double-layer plate structures destroyed by underwater contact explosion was performed using finite element method(FEM). The results of crevasse form, and response curves of displacement, effective stress and pressure versus time of the double-layer structures under explosion load were gained and compared with the responses of the flat plate model and the stiffened plate model under same explosion load. This reseach may be applied in designs of submarine, ship as well as torpedo warhead.

Modeling and Compensating Method of Temperature Error for Fiber-optic Gyroscope

LI Zhan, JI Bang-jie, GUO Lin-na, HONG Jian-ying

2008, 16(4): 015-18. doi: 10.11993/j.issn.1673-1948.2008.04.004

[Abstract](1960) [PDF 436KB](695)

Abstract:
Temperature is the key factor causing output error of fiber-optic gyroscope(FOG). To improve output precision of FOG, the temperature characteristic of FOG is theoretically analyzed, and zero drift test and rate test in full temperature range (-300 ℃～+700 ℃) are conducted. Based on the analysis of the experimental data, error compensating models of temperature versus zero drift and temperature versus scale factor are established using polynomial method. Experimental results indicate that the compensation model can improve output precision of FOG in full temperature range by one order of magnitude.

Model Expanding Process in Federation Member of Torpedo Operational Simulation System

LIU Xue-chen, XU Feng

2008, 16(4): 019-23. doi: 10.11993/j.issn.1673-1948.2008.04.005

[Abstract](1556) [PDF 628KB](746)

Abstract:
Model drive architecture (MDA ) -based development process - model expanding process(MEP) is presented. For using MDA, and combining unified modeling language (UML) , extensible markup language(XML), base object model (BOM) and other technologies, the focus of development work is transferred from program code to model design with higher abstract level. A concept model of torpedo operational simulation system is designed based on MEP. Based on BOM, the development of system federation object model/simulation object model(FOM /SOM) and the platform independent model(PIM)of the federation member are implemented. In addition, executable code is generated with MDA, and the analysis of typical simulation application is finished.

Application of Virtual Reality to Bottom Tracking of Autonomous Underwater Vehicle

GUI Zhi-Hui, YAN Wei-sheng, Gao Jian, MA Wen-Jie

2008, 16(4): 024-26. doi: 10.11993/j.issn.1673-1948.2008.04.006

[Abstract](1878) [PDF 350KB](694)

Abstract:
Based on software platform Vega and MultiGen Creator, a simulation system of autonomous underwater vehicle(AUV) for bottom tracking has been developed. The selection of software, the model construction, the generation of virtual ocean environment and terrain, the implementation of fuzzy rules, and the application of virtual reality techniques are all introduced in detail. Simulation results show that this simulation system can precisely simulate the interaction in the environment, and realistically display the dynamic bottom tracking process of AUV. The simulation system may be applied to the simulation of obstacle avoidance control and cooperating control of AUV in the future.

Active Vibration Control Optimization Based on NSGA-II

MENG Xiang-zhong, SHI Xiu-hua, DU Xiang-dang

2008, 16(4): 027-30. doi: 10.11993/j.issn.1673-1948.2008.04.007

[Abstract](2101) [PDF 438KB](612)

Abstract:
Fast and elitist multi-objective genetic algorithm(NSGA-II) is based on Pareto-optimal front with low computation requirement, elitist approach, and simple constraint-handling strategy. NSGA-II can search the representative and satisfactory Pareto-optimal solutions for expert to objectively select the optimal solution according to weight values of objective functions and different purposes, which is the incomparable advantage over single-objective optimization algorithm. Taking structure vibration energy and system control energy as multi-objective optimization functions of a structure vibration system, an multi-objective optimal disposition model is established including placement, quantity and length of sensors and actuators, and control gain of active vibration control system. A cantilever simulation with NSGA-II as optimization strategy verifies the effectiveness and feasibility of the presented method.

A Numerical Evaluating Model for Edge Diffraction Effect on Sound Insulation Measurement in Free-Field

LIU Yan-sen, SHENG Mei-ping, WANG Peng, ZHANG Jun-feng

2008, 16(4): 031-35. doi: 10.11993/j.issn.1673-1948.2008.04.008

[Abstract](1284) [PDF 611KB](638)

Abstract:
In underwater acoustic engineering, improving precision of acoustic measurement for materials in free-field is very important in design of acoustic stealthy of underwater vehicle. In this paper, a numerical method to evaluate the edge diffraction effect on sound insulation measurement in free-field was investigated using finite element method (FEM) and boundary element method (BEM) based on the commercial sound and vibration analysis software LMS-SYSNOISE. The theoretical analysis model, analysis condition and analysis procedure are on the basis of real measurement. Numerical calculation and analysis were carried out for the influence of edge diffraction on both axial and off-axial receives in a underwater normal sound insulation measurement of a steel plate. The results show that edge diffraction effect is strongly dependent on the ratio of plate dimension to measured frequency wavelength, and the geometrical configuration of sound sources, plate and receiving field point. In addition, compared with axial receiving, off-axial receiving with small angle is in favor of restraining edge diffraction effect with certain frequency ranges, and the restraining efficiency is associated with off-axial distance and relative axial distance.

Incoming Torpedo Detecting Method Based on Horizontal Bearing Rate of Wake Homing Torpedo Trajectory

SUN Chang-cun, REN Zhi-liang, CHEN Guang, JIAO Zhong-ao

2008, 16(4): 036-39. doi: 10.11993/j.issn.1673-1948.2008.04.009

[Abstract](1963) [PDF 441KB](765)

Abstract:
Target signal detection technique is one of the key problems in developing suspended hard kill rockets for anti-torpedo. To solve the problem of burst-point judgment for suspended hard kill rocket to intercept a wake homing torpedo, a threshold detection method for detecting wake homing torpedo is proposed based on the simulation analysis of bearing rate in horizontal plane under different collision situations. Simulation results show that burst-point judgment depends on whether wake homing torpedo enters action zone or not. According to the critical condition of collision, calculating method of detection threshold is presented, and the detection principle is explained. In addition, the application prospect of the method is discussed.

Maneuvering Target Tracking Algorithm Based on Improved Truncation Gaussian Probability Model

JIAO Ya-meng, FENG Xi-an, HUANG Jian-guo, ZHANG Yin

2008, 16(4): 040-42. doi: 10.11993/j.issn.1673-1948.2008.04.010

[Abstract](1434) [PDF 469KB](657)

Abstract:
Maneuvering target model is a key element in underwater target tracking. Based on truncation Gaussian probability model for underwater target tracking, an improved maneuvering target tracking algorithm is presented in this paper. The algorithm utilizes the difference between observation value and state estimation of previous two sample positions to update the model′s self-adaptation of maneuvering acceleration and its variance, and avoids adverse influence of acceleration limit presupposition. Simulation result shows that this algorithm has good performance of tracking underwater maneuvering target with higher accuracy.

Acoustical Frequency Hopping Communication Method Resisting Multipath in Shallow Water

TIAN Liang, WANG Ming-zhou, WANG Hai-lu

2008, 16(4): 043-46. doi: 10.11993/j.issn.1673-1948.2008.04.011

[Abstract](1424) [PDF 469KB](649)

Abstract:
Intersymbol interference(ISI) due to shallow water multipath seriously influences underwater acoustical communication. To resist multipath and ISI in acoustical communication, a single filter receiving method and a new method, namely preprocessing frequency hopping filtering method, were adopted simultaneously. A controlled preprocessing frequency hopping filter was added before mixing frequencies of signal receiving system to strengthen resistance against multipath and ISI. The method was simulated respectively on two frequency hopping sequences of PN code and increasing sequence. Simulation results show that the bit error rate(BER) can be decreased by using the increasing frequency hopping sequence. The BER reaches 10^-4 when signal noise ratio(SNR) is greater than 10 dB and energy ratio of series interference signal to direct arrival signal is litter than 0.6.

Receiving Signal Models and Parameters Optimization for Defence System Against Wake Homing Torpedo

LIANG Hong, LIU Jin-bo

2008, 16(4): 047-50. doi: 10.11993/j.issn.1673-1948.2008.04.012

[Abstract](1887) [PDF 508KB](765)

Abstract:
The scatter model of ship wake has been presented based on sea surface reverberation theory and acoustic characteristic of bubble to improve defense against the threat of wake homing torpedo. The features of wake echo signal are analysed and calculated quantitatively by combining the measurement data from abroad. The results show that echo pressure depends mainly on size and quantity of bubbles, ship′s immersion depth and speed, and transmission frequency of array. Moreover, this paper presents the design principle and parameters selection for defense system, such as transmission frequency, pulse width and period, as well as work range and depth.

Ship Evasive Strategy while Releasing Suspended Depth Charge Against Acoustic Homing Torpedo

LIN Xian-jie, JIA Yue, ZHAO Xue-tao

2008, 16(4): 051-53. doi: 10.11993/j.issn.1673-1948.2008.04.013

[Abstract](2025) [PDF 469KB](743)

Abstract:
Evasive maneuver is one of key problems a surface ship faces while releasing suspended depth charge to intercept a torpedo. This paper analyzes the process of depth charge intercepting torpedo, establishes a model of ship evading acoustic homing torpedo, and obtains the evasive turning angle as evading torpedo in different torpedo alert areas by using Monte-Carlo method. Simulation result shows that expectant evasive probability can be achieved with non-evasion or small angle evasion under the cover of suspended depth charge array.

Operational Concept of Long-range Torpedo and Its Technical Requirements

LI Ben-chang, LIANG Tao

2008, 16(4): 054-57. doi: 10.11993/j.issn.1673-1948.2008.04.014

[Abstract](1545) [PDF 545KB](707)

Abstract:
Taking defence against ship formation as background, this paper discusses the tactical reasons, technical conditions and possibility for developing long-range torpedo, and puts forward the concept of submarine group attacking and guidance way by using leading torpedo. Moreover, operational concept of realizing long-distance attack against ship formation and regarding torpedo as launching-platform or anterior detector is presented, and major technologic characters and functional requirements of the long-range torpedo are analyzed.

Influence of Target Motion Factors Error on Calculating Ultimate Range of Wire Guided Torpedo

SONG Jian-feng, HUANG Wen-bing

2008, 16(4): 058-62. doi: 10.11993/j.issn.1673-1948.2008.04.015

[Abstract](2031) [PDF 534KB](678)

Abstract:
This paper establishes a simulation model for calculating the ultimate range of wire guided torpedo to attack a moving warship with rectilinear uniform velocity based on the analysis of calculation method of ultimate range of wire guided torpedo and influence factors. The model employs the method of target bearing modification to launch torpedo, uses the "keeping distance for wire and wake guide" method on wire guided distance and the wake homing mode on homing pursuit distance. The ultimate ranges of torpedo are calculated with different errors of target motion factors according to the surface ship′s velocity and board angle values as well as their error scope obtained from command and control system. Furthermore, the calculation result is evaluated to improve acquisition probability of wire guided torpedo.

2008 Vol. 16, No. 4

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