水下无人系统学报

Mathematical Simulation of Unsteady Ventilated Supercavitation

WANG Gai-di, Lü Yan-hui, ZOU Qi-ming

2012, 20(5): 321-325. doi: 10.11993/j.issn.1673-1948.2012.05.001

[Abstract](866) [PDF 322KB](589)

Abstract:
Considering the complex factors concerned in ventilated supercavitation, such as time-variable characteristic, difficult realization and high cost, mathematical simulation of unsteady ventilated supercavitation is studied. Based on the principle of independence of cavity sections expansion(Logvinovich′s principle), an model of unsteady ventilated supercavitation is established, and corresponding simulation method is presented. The factors influencing supercavita-tion shape are simulated dynamically. Consequently, the supercavitation′s shape change regularity and its relative posi-tion to underwater vehicle surface are obtained at different ventilation parameters and moving parameters, and the re-quirements of cavity close position for satisfying vehicle high-speed steady motion are proposed. This study may offer a reference for designing ventilating system and running capability of an underwater high-speed vehicle.

Maneuverability Analysis of a Hybrid Power Underwater Glider

SONG Bao-wei, MENG Xiang-yao

2012, 20(5): 326-330. doi: 10.11993/j.issn.1673-1948.2012.05.002

[Abstract](1436) [PDF 230KB](554)

Abstract:
Hybrid power underwater glider is a new kind of underwater glider equipped with rudders and propeller system. To validate its performance, the maneuverability under different working conditions in the ocean environment was investigated. A mixed working mode was proposed for a hybrid power underwater glider to improve its navigation capability, i.e. adjusting the center of gravity when the glider is powered, and operating rudders when it is gliding without power. Spatial motion equations were established according to the momentum theorem and the moment of momentum theorem, and a mathematical model of ocean current was constructed. Then different working conditions were simulated numerically. The results show that satisfactory maneuverability and stability of the transition between unpowered gliding and powered propulsion are obtained, but deviation due to ocean current occurs during unpowered gliding period; and the proposed mixed working mode is feasible.

Application of Titanium and Titanium Alloys to Ships of US Navy

KUANG Meng-sheng, HU Wei-min, GUO Ai-hong, WU Shi-dong, JIANG Peng

2012, 20(5): 331-335. doi: 10.11993/j.issn.1673-1948.2012.05.003

[Abstract](928) [PDF 210KB](707)

Abstract:
The advantages of titanium and its alloys in marine environment, as well as the achievements in development and appli-cation of these materials for new ships of US Navy, are discussed. The main trends of developing titanium and titanium alloys for US Navy are analyzed, i.e. developing more types of titanium alloys according to different environmental requirements, increasing the kinds of titanium alloys for navy usage, reducing cost of titanium alloys, and improving welding materials and techniques.

Statistical Noise Distribution Modelling for Underwater Acoustic Signals Based on SαS

LIN Wei, WANG Han-qing, YUAN Bing-cheng, WANG Ping-bo

2012, 20(5): 336-338. doi: 10.11993/j.issn.1673-1948.2012.05.004

[Abstract](1388) [PDF 252KB](719)

Abstract:
To accurately describe statistical noise distribution of underwater acoustic signal, we established a statistical noise distribution model of the acoustic signal based on relevant features of symmetric α-stable( SαS) distribution. Firstly, the model configuration for describing noise characteristics of underwater acoustic signal with reverberation was designed by considering the features of noise probability distribution of acoustic signal. Then, the range of index α was determined by trials in tank, lake and sea, respectively, in different acoustic environments. The analysis of the test data shows that the proposed SαS distribution-based model is applicable.

Parameter Estimation of Underwater Scale Target Based on Improved Huber-Estimation

YANG Xiang-feng, YNAG Yun-chuan, GUO Lei

2012, 20(5): 339-343. doi: 10.11993/j.issn.1673-1948.2012.05.005

[Abstract](1389) [PDF 245KB](579)

Abstract:
Scale target parameters are the key parameters for short-range trajectory maneuvaer and perpendicular hit attack of underwater acoustic homing weapons. Effective estimation of the characteristic parameters of scale target is important to ensure the operational destructive effect of underwater acoustic homing weapons. To reduce the scale parameter estimation errors from least squares fitting, this paper proposes an parameter estimation method of underwater scale target based on the improved Huber estimation, calculates the iterative fitting weight matrix via the proposed method by making use of target highlight strength and fitting error. Hence, target′s length, course angle and equivalent point are estimated effectively by eliminating inter-ference highlight via fitting error. Simulation and sea trial show that the proposed method can effectively eliminate interference point, and has steady convergence performance, greater anti-interference capability and higher parameter estimation accuracy.

Application of Joint Diagonalization Technology to Spatial Specturm Estimation

ZHAO Long-long, SONG Hai-yan

2012, 20(5): 344-347. doi: 10.11993/j.issn.1673-1948.2012.05.006

[Abstract](1001) [PDF 220KB](628)

Abstract:
In practical engineering applications, the performance of conventional spatial spectrum estimation method gets degraded due to the effects of noise, interference and sampling effect, etc. In order to reduce these effects on direction of arrival (DOA) estimation, this paper uses the joint diagonalization to construct the joint diagonalization structure of the spatial-time correlation matrix groups, and obtains a spatial spectrum estimation method based on Jacobi rotation or-thogonal joint diagonalization. Thus, corresponding eigenvalues and eigenvectors are utilized to obtain the revised co-variance matrix, and the spatial spectrum estimator is revised. Simulation results show that, under different signal to noise ratio(SNR) and snapshots, the proposed method can significantly improve the DOA estimation performance of the conventional spatial spectrum estimation method.

Design on Underwater Broadband Acoustic Transducer with Three Different Shape of Radiator and Its Application to Sonar Array Arrangement Technology

TIAN Feng-hua, LIU Ya-ying, HE Wen-feng

2012, 20(5): 348-352. doi: 10.11993/j.issn.1673-1948.2012.05.007

[Abstract](816) [PDF 324KB](533)

Abstract:
Underwater broadband acoustic transducers with round, square and hexagonal radiators are designed by using finite element method and software ANSYS to make full use of sonar array space, increase radiant area and hence im-prove overall characteristics of a sonar array. Under the conditions of same radiant area, piezoelectric elements, and length of transducers, etc., the influences of the radiators in the above three shapes on the resonance frequency, trans-mitting voltage response, receiving sensitivity of free field voltage, and receiving/transmitting frequency bandwidth of underwater broadband acoustic transducers are simulated, and the transducer structure is optimized. The transducers with the three shapes of radiators are fabricated and tested in a tank, respectively. The test results agree well with the calculations. In addition, the effectiveness of three arrangements of acoustic transducers is evaluated for same sonar window dimension.

Passive Underwater Target Tracking Based on Bearings-Only Angle Measurement

SONG Xu-dong, YU Jing, LI Xiao-hua, LI Ya-an

2012, 20(5): 353-358. doi: 10.11993/j.issn.1673-1948.2012.05.008

[Abstract](1423) [PDF 328KB](613)

Abstract:
In regard to actual application of passive underwater target tracking technology based on bearings-only angle measurement, several algorithms for monostatic and bistatic sonar systems, i.e. the pseudo-linear estimation (PLE), the extended Kalman filter (EKF), and the unscented Kalman filter (UKF), are discussed, and their performances are simu-lated with different parameters, respectively. Simulation results illustrate that: 1) The nonmoving monostatic sonar sys-tem can not obtain all-around observation of target, but when prior information of the target velocity is available the trajectory of the target can be acquired by using the PLE algorithm; 2) The bistatic sonar system can achieve all-around observation of target, and the performance of the UKF is better than that of the EKF when the observation equation is very nonlinear.

Design of Yaw Angular Velocity Controller for Anti-Torpedo Torpedo Based on Bank-to-Turn

GAO Xuan, ZHOU Xu-chang, PAN Xun

2012, 20(5): 359-362. doi: 10.11993/j.issn.1673-1948.2012.05.009

[Abstract](1592) [PDF 150KB](619)

Abstract:
To enhance maneuverability of anti-torpedo torpedo(ATT), a new yaw angular velocity controller for ATT is designed by analyzing and adopting conventional PID control, intelligent PID control, predictive functional control(PFC), and fuzzy adaptive PID control, respectively based on bank-to-turn(BTT) control mode. Simulation results show that, com-pared with conventional PID control, intelligent PID control, PFC and fuzzy adaptive PID control make system control process smoother, faster and more accurate without overshoot. Particularly, PFC is more suitable for yaw angular velocity control of ATT because of its fastest response and least calculation.

Calculation and Analysis on Cooling Exhaust-gas of Torpedo Gas Turbine with Water spray

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

2012, 20(5): 363-366. doi: 10.11993/j.issn.1673-1948.2012.05.010

[Abstract](1304) [PDF 183KB](670)

Abstract:
To reduce harmful influence of torpedo gas turbine′s high-temperature exhaust-gas on the seal, bearings and lubrication, as well as the track of a torpedo, the principle of cooling turbine exhaust-gas with water spray is described. Corresponding calculation models are established following the theories of engineering thermodynamics and fluid dy-namics to calculate the parameters in cooling exhaust gas process with different conditions. Consequently, the optimum water consumption and the thermomechanical parameter of exhaust-gas after cooling are obtained. The calculated results could provide a technical support for cooling system design of torpedo gas turbine.

Direct Torque Control for Brushless DC Motor

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

2012, 20(5): 367-370. doi: 10.11993/j.issn.1673-1948.2012.05.011

[Abstract](1220) [PDF 275KB](642)

Abstract:
To reduce the torque ripple generated in commutation period of blushless DC motor (BLDCM), the direct torque control (DTC) is used to control BLDCM. The direct torque control principle is analyzed, and a direct torque control scheme for BLDCM without observation of flux linkage is proposed according to the characteristics of BLDCM. In this scheme, a hysteresis-controlled torque loop is adopted, and the voltage space vectors are determined by torque loop output and position of magnetic poles. Simulation and experimental results indicate that the DTC method can sig-nificantly reduce the torque ripple of BLDCM and gain perfect dynamic performances.

Discussion on Rapid Formation of Battle Effectiveness of Underwater Weapon Warhead

HUANG Feng-jun, ZHAO Jin-hong, ZHANG Jun-hu

2012, 20(5): 371-374. doi: 10.11993/j.issn.1673-1948.2012.05.012

[Abstract](1205) [PDF 169KB](570)

Abstract:
To enhance battle effectiveness of underwater weapon warheads, we analyze the factors influencing battle effectiveness formation in accordance with the three basic requirements for forming battle effectiveness. The methods and ways for forming and enhancing battle effectiveness in the fields, such as personnel training, warhead development, support and guarantee, and daily military training, are presented. Some suggestions about the mode and content of col-lege education and army training are offered. The decision-making from top management layer in development phase, optimally utilizing information, and further promoting “generalization, serialization, and combination” are talked. More-over, the whole process of program, implementation and application for enhancing battle effectiveness formation is con-sidered, and some corresponding suggestions are offered.

Simulation of Explosive Damage Effect of ATT Warhead on Incoming Torpedo

LIU Rui, LU Zhong-bao, WANG Ming-zhou

2012, 20(5): 375-379. doi: 10.11993/j.issn.1673-1948.2012.05.013

[Abstract](1079) [PDF 358KB](614)

Abstract:
To assess the damage effect of anti-torpedo torpedo (ATT) warhead on an incoming torpedo, we establish an incoming torpedo model with the finite element analysis software ANSYS LS-DYNA, simulate the explosive damage effect of ATT warhead on an incoming torpedo with different distances and different angles by using the fluid-solid cou-pling algorithm, and obtain the damage radius of ATT warhead, the damage criterion of an incoming torpedo, and the damage laws of an ATT against an incoming torpedo. Simulation results show that deformation and fracture occur more easily on the shell of fuel tank section of an incoming torpedo than on other shells in underwater explosion. This study may benefit the damage effect assessment of an ATT and the research of ATT warhead.

An Idea about Shaped Charge Warhead with Combined Charge Liner for Torpedo

ZHOU Fang-yi, ZHAN Fa-min, JIANG Tao, ZHANG Ke-yu

2012, 20(5): 380-383. doi: 10.11993/j.issn.1673-1948.2012.05.014

[Abstract](1345) [PDF 336KB](683)

Abstract:
To increase the power of torpedo warhead, an idea about shaped charge warhead with combined charge liner is proposed. The structure of warhead is designed, its working mechanism is analyzed, and numerical simulation is per-formed with the finite element analysis software ANSYS/LS-DYNA to obtain the stress field distribution in the monolayer target, which is penetrated by the warhead. Simulation result shows that the warhead with combined charge liner can provide movement space by making use of former shaped charge jet for latter explosively formed projectile (EFP), which leads to higher destructive effect to target than a normal warhead does.

Storage Reliability of Equipment on Duty at Ground and Evaluation Method

WANG Yu-liang, ZHANG Jing-yuan, DING Ping

2012, 20(5): 384-387. doi: 10.11993/j.issn.1673-1948.2012.05.015

[Abstract](994) [PDF 165KB](585)

Abstract:
This paper presents a concept of storage reliability of equipment on duty at ground, and puts forward a classi-cal statistical evaluation method and a Bayesian evaluation method according to ground environment of equipment which is on duty and existing data type. Corresponding evaluation procedures of storage reliability are proposed, and storage reliability of equipment on duty at ground is evaluated with the above two methods, respectively, based on the test data to obtain its variation tendency. The present storage reliability of equipment on duty at ground may be taken as one of the quantitative parameters for usage reliability evaluation of equipment, and may provide a reference for im-proving storage reliability of equipment.

Bayesian Assessment Method of Loading Reliability for Rocket-Assisted Torpedo

QI Li-xin, NING Yong-cheng, XING Guo-qiang

2012, 20(5): 388-391. doi: 10.11993/j.issn.1673-1948.2012.05.016

[Abstract](1175) [PDF 216KB](535)

Abstract:
According to the characteristics of complex system and small sample number of rocket-assisted torpedo, we estimate loading reliability by using Bayesian assessment method to fuse a prior information. The Kullback informa-tion method and the optimization method are adopted to rectify the subjective problem in traditional environmental fac-tor calculation and test scenario design, and enhance the accuracy and objectivity of test scheme. Concrete assessment scenario is given on condition that the risk of consumer equals that of producer according to preset tactical and technical specifications.

Error Analysis of Measuring Water Entry Point for Rocket-Assisted Torpedo

ZHANG Yu-Tao, XUE Fei, LI Peng

2012, 20(5): 392-395. doi: 10.11993/j.issn.1673-1948.2012.05.017

[Abstract](843) [PDF 585KB](498)

Abstract:
Absence of buoys used for hydroacoustic localization in sea trial may reduce measurement accuracy of water entry point of a rocket-assisted torpedo. In this paper, the preset buoy array for measuring water entry point of a rocket-assisted torpedo is simulated with the software Matlab, and the effect of absence of some buoys on measurement accuracy of water entry point is analyzed. The results show that when absent buoys and buoy array reach to the lower limit, i.e. 4 of 12 buoys are absent and the buoy array is asymmetric, the measurement accuracy will decrease rapidly. Therefore, if the topology of preset buoy array does not satisfy the lower limit, the array must be adjusted.

Test and Evaluation of Shooting Range Dispersion for Wire-guided Torpedo

ZHU Wen-zhen, YE Hao-jie, LIU Bo

2012, 20(5): 396-400. doi: 10.11993/j.issn.1673-1948.2012.05.018

[Abstract](1087) [PDF 225KB](634)

Abstract:
Torpedo shooting range dispersion is an important index in evaluating a wire-guided torpedo’s attacking abil-ity, and it is also a principal index in wire-guided torpedo test and evaluation. In this paper, the cause of shooting range dispession during guidance of a wire-guided torpedo is analyzed, and two models of torpedo’s location error and depth error are constructed. Test items and samples are determined following the design theory of torpedo test, and design principle of torpedo test scheme as well as evaluation method of the test are presented by analyzing the main factors influencing wire-guided torpedo shooting range dispersion. This study provides a theoretical foundation for designing test and evaluation method of torpedo shooting range dispersion, and also offers a reference for wire-guided torpedo combat simulation and operational effectiveness evaluation.

2012 Vol. 20, No. 5

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