水下无人系统学报

Cavity Shape and Drag Characteristics of Underwater High-speed Projectile

YI Hui, ZHANG Yu-wen, YUAN Xu-long, WANG Ya-dong

2011, 19(4): 241-245. doi: 10.11993/j.issn.1673-1948.2011.04.001

[Abstract](1235) [PDF 376KB](650)

Abstract:
Experimental study of projectile has many restrictions under underwater high-speed motion with cavity. To obtain the variation rules of cavity shape and drag characteristics of an underwater high-speed projectile, we investigated cavity shape and drag characteristics of the projectile by using computational fluid dynamics (CFD) and a formula based on the independent expansion principle of cavity sections. Conclusions are drawn that the numerical simulation agrees well with the computation of the formula; the relative length, relative diameter and slenderness ratio of cavity increase with the reduction of cavitation number; for small cavitation number, the shape of cavity front changes little, and the stable pressure difference coefficient becomes the main part of drag coefficient. We suggest the steps of shape design of the underwater high-speed projectile as follows: 1) tentative modeling by formula computing; 2) modifying model by numerical simulation; 3) establishing model by experimental method.

Method for Imposing Discrete Loads on Curved Surface in Simulation Analysis

XU Xin-dong, LI Jian-chen, CAO Xiao-juan, GONG Ping

2011, 19(4): 246-249. doi: 10.11993/j.issn.1673-1948.2011.04.002

[Abstract](1483) [PDF 731KB](730)

Abstract:
To solve the problem of imposing a mass of discretely distributed loads on curved surface, and improve the efficiency and quality of finite element method (FEM) analysis, a subarea polynomial fitting method of curved surface based on curve fitting and linear interpolation is proposed. With axisymmetric curved surface revolved by a monotonous curve, the functions of the discrete loads along the surface subareas are derived, then the loads are imposed on the whole curved surface through the functions for simulation analysis. Hence, the efficiency of pre-process for the FEM is enhanced. The simulation of model wind tunnel test indicates that this method is simple and effective with high precision.

Influence of Water-entry Parameters on Trajectory of Homing Depth Charge in Attacking Submarine

CHENG Shan-zheng, YE Li-min, LI Zong-ji, TIAN Bing

2011, 19(4): 250-254. doi: 10.11993/j.issn.1673-1948.2011.04.003

[Abstract](1095) [PDF 408KB](670)

Abstract:
In order to analyze the trajectory of a homing depth charge in attacking a submarine, we establish a mathematical model of longitudinal trajectory for the homing depth charge, and simulate the trajectory of the depth charge with different water-entry parameters in attacking a submarine with uniform rectilinear motion by using the software MATLAB/Simulink. Simulation result indicates that water-entry parameter exerts significant influence on trajectory of the depth charge in attacking a submarine. This research may be helpful in tactical application of airdropping a homing depth charge.

An Optimized Algorithm of Feature Extraction for Vessel Base Frequency

LIU Yi-hai, ZHANG Xiao-min, ZHAO Yan-an, GUO Si-ming

2011, 19(4): 255-259. doi: 10.11993/j.issn.1673-1948.2011.04.004

[Abstract](1199) [PDF 385KB](710)

Abstract:
Shaft frequency, which is an essential feature of different vessel targets, possesses a crucial application value to the underwater targets detection. Based on the base frequency analysis of target propeller noise with multiple autocorrelation, we propose a one-dimensional fuzzy judgment method to get the credible degree of the base frequency in each base frequency band. Adopting the component of the linear spectrum and its corresponding credible degree threshold of base frequency, the purpose of extracting target’s characteristic base frequency is realized to identify the target. The sea trial results show that the proposed base frequency extraction method based on multiple autocorrelation power spectrum and credible degree threshold filtering of information fusion is effective and feasible in underwater target detection with a detection probability of 92.5%.

Influence of Torpedo Speed on Submarine′s Torpedo Warning Distance

CAO Zhen-qing, JIA Yue

2011, 19(4): 260-262. doi: 10.11993/j.issn.1673-1948.2011.04.005

[Abstract](1135) [PDF 254KB](980)

Abstract:
To study the operational application of double-speed anti-submarine torpedo under the effect of submarine′s torpedo warning sonar, the influences of the variations of torpedo speed and deep on its radiation noise intensity are analyzed by using the empirical formula of radiation noise. According to the analysis of passive sonar equation, the variation rule of the warning distance of torpedo sonar is investigated for varying torpedo speed. Calculation result shows that torpedo warning distance increases with torpedo speed. It is suggested that attention be paid to presenting torpedo speed in the operational application of double-speed torpedo to reduce the torpedo warning distance by low speed running, and to enhance stealth of the torpedo and success probability of the attack.

Design and Implementation of Target Simulator with Acoustic Coupling for Torpedo Homing System

YANG Zhan-long, CHEN Hang, WANG Xin-hong, QI Qian

2011, 19(4): 263-267. doi: 10.11993/j.issn.1673-1948.2011.04.006

[Abstract](1731) [PDF 885KB](700)

Abstract:
Most existing underwater target simulators for sonar and torpedo homing system were designed without considering the characteristics of transducer array for signal receiving. To test comprehensively the performance of torpedo homing system in laboratory, we designed and implemented a target simulator with acoustic coupling, including the array element signal simulator and acoustic coupling device. This paper introduces the architecture and functions of the target simulator with acoustic coupling, the hardware platform development of a multi-DSP parallel processing system, the designs of acoustic coupling array and transducer array elements, and the selection of acoustic coupling material. The performance test for the developed target simulator was conducted and the coupled element signals were tested with the existing torpedo homing system. The results verify the feasibility and effectiveness of the target simulator with acoustic coupling. This target simulator can overcome the influence of inexactly modelling transducer array, and reduce the number of underwater tests for torpedo homing system.

A Method for Quickly Acquiring Maniflod of Measured Broadband Array

GUO Tao, WU Ya-jun

2011, 19(4): 268-270. doi: 10.11993/j.issn.1673-1948.2011.04.007

[Abstract](1267) [PDF 336KB](645)

Abstract:
A rapid acquirement method of measured broadband array based on fast Fourier transform (FFT) is proposed to shorten the measurement time and simplify the signal processing during the acquirement period. Combining underwater receiving acoustic array, broadband array manifold is obtained from measured data, and beamforming is hence completed by using the array manifold. Comparison of measured data and simulation data verifies the feasibility and effectiveness of the method. Experimental results show that this method has the advantages of faster measurement and simpler calculation than the conventional method, and can be applied to beam optimization and manifold measurement of broadband acoustic array.

Way-Point Tracking Control of an Underactuated AUV in the Presence of Ocean Current Disturbance

XIA Liang-sheng, YAN Wei-sheng

2011, 19(4): 271-275. doi: 10.11993/j.issn.1673-1948.2011.04.008

[Abstract](1397) [PDF 337KB](675)

Abstract:
This paper addresses the problem of way-point tracking control of an underactuated autonomous underwater vehicle (AUV) in the presence of ocean current disturbance. Kinematics and dynamics models for the AUV with three degrees of freedom in horizontal plane are established. A kinematic controller is designed with the dummy inputs of forward speed and angular velocity relative to the current. Then a dynamic controller is derived based on the Lyapunov theory and the backstepping techniques. Simulation results show that the underactuated AUV can effectively track the way-points in the inertial frame and reach the final destination with asymptotically converged tracking errors.

Application of SLAM Algorithm Based on Image Sonar to AUV Integrated Navigation

LIU Ming, ZHANG Yan, XU De-min

2011, 19(4): 276-281. doi: 10.11993/j.issn.1673-1948.2011.04.009

[Abstract](1487) [PDF 504KB](1087)

Abstract:
To improve the long-distance or deep-sea navigation and localization precision for an autonomous underwater vehicles(AUV) within limited volume, power and cost, an algorithm of simultaneous localization and mapping(SLAM) based on image sonar is presented for AUV underwater integrated navigation system. According to the data of real-time distance between each feature on map and an AUV, the data of three-dimensional bearing from image sonar and the data of navigation from strapdown inertial navigation system(SINS), the carrier state and map state can be estimated and measured simultaneously and continuously by extended Kalman filter(EKF). The errors are fed back to SINS for correction, hence the accumulated errors of attitude, velocity and position increasing with running distance and time can be effectively inhibited. Furthermore, the accuracy of features identification can be improved by putting acoustics size element into map features vector. Simulation result shows that this method can effectively inhibit errors of inertial navigation by continuously measuring valid features on map. Particularly, the localization accuracy of an underwater integrated navigation is significantly enhanced when same landmarks are observed repeatedly in cruise or return voyage of an AUV.

A Time Delay Compensation Algorithm for Transfer Alignment in Strapdown Inertial Navigation System

XU Xiang

2011, 19(4): 282-284. doi: 10.11993/j.issn.1673-1948.2011.04.010

[Abstract](1428) [PDF 231KB](597)

Abstract:
To reduce the influence of time delay, and enhance the precision of transfer alignment for movable base, a compensation algorithm for information transmission time delay between master and slave strapdown inertial navigation systems (SINS) in transfer alignment is proposed. The algorithm uses the delay-time and the relevant data in solving process of the slave inertial navigation system to compensate the errors caused by time delay in information transmission, and performs transfer alignment of the movable base according to the corrected information of master inertial navigation system. Test results show that the proposed algorithm can improve the transfer alignment accuracy and reduce transfer alignment time.

Dynamic Analysis of Torpedo Swashplate Engine Based on Virtual Prototype Technology

LI Xin, WANG Zhi-gang, WAN Rong-hua, PENG Bo, LEI Yun-long

2011, 19(4): 285-289. doi: 10.11993/j.issn.1673-1948.2011.04.011

[Abstract](1353) [PDF 612KB](752)

Abstract:
Based on the prototype technology, we establish dynamical models for different types of torpedo swashplate engines, including the engine with straight groove and static cylinder, the engine with straight groove and rotational cylinder, the engine with 8-shape groove and static cylinder, and the engine with 8-shape groove and rotational cylinder, in order to select perfect types in torpedo swashplate engine design. The dynamical performances of the different engines are simulated and analyzed by using software ADAMS. The results show that the swashplate engine with straight groove and rotational cylinder is superior to other types of engines, comprehensively considering general starting performance, self-balance characteristic, force state on key parts, and working stability. This type of swashplate engine can basically realize self-balance, and its undulation of rotational speed output is small.

Applications and Prospect of Hydrogen-Oxygen Energy in Torpedo Power System

ZHAO Jun, SHAN Xiao-liang

2011, 19(4): 290-294. doi: 10.11993/j.issn.1673-1948.2011.04.012

[Abstract](936) [PDF 270KB](724)

Abstract:
Hydrogen-oxygen energy is one of the most potential energy to a torpedo. According to development trend of a torpedo, applications of hydrogen-oxygen energy to torpedo′s thermal power system and electric power system are discussed and compared in efficiency, reliability and cost. The generation methods of hydrogen and oxygen are introduced. And the security and adjustability of the torpedo power system with hydrogen-oxygen energy are analyzed. Conclusion is drawn that the hydrogen-oxygen energy power system will be further developed because it can improve torpedo′s speed, range, running depth, stealth, and reliability.

Numerical Simulation on Temperature Field inside Sealed Battery Chamber

LI Wei, SONG Bao-wei, HU Yu-li

2011, 19(4): 295-298. doi: 10.11993/j.issn.1673-1948.2011.04.013

[Abstract](1041) [PDF 4834KB](551)

Abstract:
When a Li-ion battery bank discharges continuously at large power inside a sealed battery chamber for a long time, much heat energy will be produced and accumulated, which may cause batteries leaking, metamorphosing, exploding, and so on, and further decrease the efficiency and safety of the battery bank. So it is necessary to investigate the temperature field inside the chamber. This paper establishes a finite element model with the software ANSYS to simulate the temperature field distribution inside the battery chamber of an underwater vehicle. Simulation result indicates that the maximum temperature is lower than the critical temperature of 150 ℃ when the battery bank discharges for 2.5 hours at 40 A.

Optimization Design of Motor for Torpedo Integrated Motor Propulsor Based on Chaos Ant Colony Algorithm

WANG Ding, XIE Shun-yin, LIAN Jun-qiang

2011, 19(4): 299-302. doi: 10.11993/j.issn.1673-1948.2011.04.014

[Abstract](1588) [PDF 443KB](646)

Abstract:
To enhance power density and work efficiency of the special brushless DC motor for integrated motor propulsor (IMP) of torpedo, a hybrid optimum intelligent algorithm, named chaos ant colony algorithm (CACA), is presented. This method embeds chaos optimization algorithm into ant colony algorithm. The special brushless DC motor is optimized by making use of the high accuracy of the ant colony algorithm and the rapidness of the chaos optimization algorithm. The optimization results of the motor show that the efficiency is enhanced by 1.6% and the volume is reduced by 5.6%. The proposed chaos ant colony algorithm may become a tool for the design of special brushless DC motor of torpedo IMP.

Occupying Position Method for Surface Ships in Warship-aircraft Coordinated Anti-submarine Operation Using Rocket Assisted Torpedo

QU Yan-ming, Yang Jun, ZHOU Ming, JIANG Kai-feng

2011, 19(4): 303-306. doi: 10.11993/j.issn.1673-1948.2011.04.015

[Abstract](1698) [PDF 243KB](636)

Abstract:
For the security issue of troops in warship-aircraft coordinated anti-submarine operation using rocket assisted torpedo, we analyze the influences of shooting forbidden zone of rocket assisted torpedo and target localization on troops’ positions in warship-aircraft coordination. Considering surface ships security and target localization, we discuss emphatically the methods for anti-submarine formation disposition of surface ships, formation evolution and getting out from shooting forbidden zone, in order to provide a basis for surface ships occupying reasonable position in anti-submarine operation using rocket assisted torpedo.

Modeling and Simulation of Cooperative Defense Against Wire-guided Torpedo with Rocket Assisted Noise-jammer and Hovering Depth Charge

JIA Yue, YAO Feng-liang, DING Bei

2011, 19(4): 307-311. doi: 10.11993/j.issn.1673-1948.2011.04.016

[Abstract](1536) [PDF 285KB](651)

Abstract:
We propose a torpedo defense tactic for a vessel cooperative defense against wire-guided torpedo with a rocket assisted noise-jammer and a hovering depth charge, named hard-kill and soft-kill anti-torpedo weapons. We simulate the board angle of guided submarine based on firing principle of wire-guided torpedo, establish a model of cooperative defense against submarine-launched wire-guided torpedo using a single rocket-assisted noise-jammer and a hovering depth charge, determine the deploying strategy of hard-kill and soft-kill anti-torpedo weapons and evading course of surface ship through the optimization method in operational research, and compare the success probabilities of the cooperative defense with hard-kill and soft-kill anti-torpedo weapons and the defense with single rocket-assisted noise-jammer via simulations. The results show that the proposed tactic can increase success probability by 20% ~36% compared with only using a rocket assisted noise-jammer.

A Signal Sparse Representation and Its Application to Image Enhancement for Meteorological Facsimile Maps

ZHOU Li-jia, QIAN Zhi-bo, XU Guan-lei

2011, 19(4): 312-317. doi: 10.11993/j.issn.1673-1948.2011.04.017

[Abstract](1264) [PDF 3783KB](544)

Abstract:
In the process of torpedo run test or operational application of a naval vessel, we need a hydrometeorological support based on received meteorological facsimile maps, thus legible meteorological facsimile maps is necessary. A new noise removal algorithm for meteorological facsimile maps with zero-mean Gaussian noise is proposed in this paper based on signal sparse representation. This algorithm makes full use of self features of meteorological facsimile maps, takes meteorological facsimile base maps as dictionary functions, and decomposes these meteorological facsimile maps via the dictionary functions and matching pursuit to separate the information and noise. Experimental results show the superiority in performance over the existing methods for meteorological facsimile map enhancement.

Estimation and Simulation of Submarine Magnetic Field

SUN Quan, TANG Jin-fei

2011, 19(4): 318-320. doi: 10.11993/j.issn.1673-1948.2011.04.018

[Abstract](1288) [PDF 217KB](1045)

Abstract:
Estimation and simulation of submarine’s magnetic field are of practical significance to the development of decoy, aiming target, and magnetic field simulation detection instrument. This paper analyzes the rotary prolate spheroid model and the magnetic dipole model, and estimates the magnitude of submarine magnetic field. Comparing the magnetic fields of hollow sphere and solid sphere with high permeability, a method of applying hollow permanent magnet to simulation of submarine magnetic field is proposed, and the essential parameters of the permanent magnet are estimated with this method. This method may be taken as a tool in theoretical research and experiment of submarine′s magnetic field detection and in realization of the submarine′s magnetic field simulation for decoy and aiming target.

2011 Vol. 19, No. 4

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