水下无人系统学报

Design of Portable Outfield Test Instrument for Torpedo Fire Control System

CHEN Kai, ZHAO Gang

2009, 17(5): 001-4. doi: 10.11993/j.issn.1673-1948.2009.05.001

[Abstract](1488) [PDF 554KB](834)

Abstract:
To heighten outfield test level for military equipment, a portable outfield test instrument is developed based on the concept of virtual instrument technology, which can test and troubleshoot torpedo fire control system (FCS) out of doors. The test instrument and its function are introduced firstly. Universal serial bus (USB) based hardware architecture makes the system small and light. A user interface application is developed using LabWindows / CVI to achieve a friendly interactive interface, and low level drivers are developed using Visual C++ to realize real time hardware control. Application to outfield test shows that the instrument can raise the testing and troubleshooting efficiency, and in endowed with stable performance and friendly operational interface. The test instrument can satisfy the requirements of autotest and troubleshooting for torpedo FCS, and provide a reliable technical support to the maintenance of torpedo FCS.

Reliability Analysis and Design of Data Transmission for Torpedo Control and Homing System Based on CAN-Bus Network

DING Zhen-dong, WANG Zhi-jie, YANG Jin-hou

2009, 17(5): 005-9. doi: 10.11993/j.issn.1673-1948.2009.05.002

[Abstract](1979) [PDF 678KB](730)

Abstract:
To apply CAN-bus network to torpedo control and homing systems, we verified the data transmission of torpedo control and homing systems based on CAN-bus network via test, and designed the corresponding hardware. Attentions were paid to improve reliability of data transmission of CAN-bus network in such design sections as determining CAN-bus protocol and CAN message, planning power supply, matching CAN-bus terminal impedance, setting input-output isolation, and satisfying requirement of electromagnetic environment, etc. Experimental result shows that the CAN-bus network can meet the communication requirement of torpedo electronic system.

Multidisciplinary Design Optimization Method for Torpedo Shape

ZHAO Jia-peng, YU Feng, SHI Xiu-hua, DU Xiang-dang

2009, 17(5): 010-14. doi: 10.11993/j.issn.1673-1948.2009.05.003

[Abstract](2007) [PDF 486KB](717)

Abstract:
Based on the multidisciplinary design optimization (MDO) theory and the methods of various disciplines for torpedo shape optimization design, the torpedo shape design optimization problem is decomposed to one system optimization problem and three discipline optimization problems, including drag discipline, self-noise discipline and pressure distribution discipline. A torpedo shape multidisciplinary design optimization model is established, the coupling problems between system and each discipline and among various disciplines are resolved, and parallel computation is realized. Computation of a practical example verifies the effectiveness of the proposed method.

Simulation of Moving Features of Underwater Explosion Bubble in Different Water Depths

LU Zhong-bao, NAN Chang-jiang, BU Xiang-dong, WANG Tuan-meng

2009, 17(5): 015-18. doi: 10.11993/j.issn.1673-1948.2009.05.004

[Abstract](2031) [PDF 473KB](799)

Abstract:
In order to study the influence of different water depths on moving feature of underwater explosion bubble, a simulation model of typical charge explosion in different water depths is established using the finite element analysis (FEA) software LS-DYNA. Curves of bubble radius versus time and parameters of pressure field in different water depths are hence obtained and compared with the experimental data, indicating the validity of the simulation model. By analyzing the maximal radius, impulse period and pressure field of the bubbles, the effect of pressure in different water depths on explosion bubble is achieved. Simulation results indicate that for a same charge, the maximal radius and impulse period of the bubbles decrease with the increase of water depth, the maximal pressure is on the upside of the bubbles, and the minimum pressure is on the underside. This study may offer a reference to the assessment of the damage power of a underwater weapon warhead.

Noise Reduction of Torpedo Ultrasonic Fuze Signal Processing Based on Self-Adaptive Wavelet Neural Network

YIN Xi-peng, FAN Yang-yu, DUAN Zhe-min, CHENG Wei

2009, 17(5): 019-22. doi: 10.11993/j.issn.1673-1948.2009.05.005

[Abstract](1769) [PDF 435KB](693)

Abstract:
To remove the noise signal effectively in processing torpedo ultrasonic fuze signal, wavelet theory and artificial neural network are introduced simultaneously, and the construction method of self-adaptive wavelet neural network is given. Better fitting signal is achieved by adopting orthogonal Daubechies wavelet group and optimizing the scale parameter. Simulation result shows that this wavelet neural network can effectively suppress noise from ultrasonic fuze signal with less distortion, leading to reduction of target misjudgment and misdetection of torpedo.

Design and Simulation of Frequency-Hopping Communication System in Underwater Acoustic Fading Channels

YUE Ling, QIAN Jian-ping, WANG Ming-zhou

2009, 17(5): 023-29. doi: 10.11993/j.issn.1673-1948.2009.05.006

[Abstract](2730) [PDF 774KB](833)

Abstract:
According to the characteristics of time-varying and intensive multipath of underwater acoustic (UWA) channel, a UWA channel model with time-varying fading, multipath interference and additive white Gaussian noise (AWGN) is established. Based on the channel model, a UWA frequency-hopping communication system using noncoherent multi-frequency shift key (MFSK) modulation is designed, and the simulation methodology is described. Simulation results of the system performance under Rayleigh fading channel and Rician fading channel are achieved and analyzed to provide a reference for parameters selection and performance optimization of FH/MFSK system. The results show that the proposed communication system can effectively suppress the multipath interference, and has certain immunity to Doppler spread, therefore reliable underwater acoustic communication can be implemented with the communication system.

Performance Analysis and Design of Cymbal Transducer with Low Frequency

WANG De-shi, DU Yi-qun

2009, 17(5): 030-34. doi: 10.11993/j.issn.1673-1948.2009.05.007

[Abstract](1810) [PDF 585KB](616)

Abstract:
Cymbal transducer composed of metal and piezoelectric ceramic has the advantage of small volume, which is significant in development of low frequency transducer. The effects of media on admittance and resonance frequency of cymbal transducer are analyzed with the finite element analysis, the performances of cymbal and Langevin transducers are compared, and the property variation of cymbal transducer with the physical parameters of the ceramic and the structural parameters of the metal cap is determined. Moreover, a prototype of cymbal transducer with low frequency is designed. This study may be helpful for optimizing cymbal transducer and developing low frequency transducer in underwater applications, and may provide technical support to fabrication technique and tank experiment.

Simulation and Application of Acoustic Transmission in Shallow Sea Based on Ray Method

WEI Lai, ZHOU Sui-hua, ZHANG Jing-yuan

2009, 17(5): 034-39. doi: 10.11993/j.issn.1673-1948.2009.05.008

[Abstract](1923) [PDF 607KB](602)

Abstract:
Aiming at the acoustic transmission with 3 km in the shallow sea, an integrative simulation model is built based on the conceptions of the stepping sound ray tracing method and sound abnormity factor. The effects of the propagation path and the sound ray bend due to transmitter and receiver positions and hydrological condition on the sound-field strength are considered in the model. With this model, a principle of identifying sound ray step and density is proposed,the equations of sound abnormity factor and sound transmission loss are modified, and the relation between sound ray density and sound-field strength is presented. Two sets of sea trial data collected by corresponding acoustic equipments show that the effects of sound ray bend and propagation path on sound-field strength can not be ignored in the shallow sea acoustic simulation. This model is effective in simulating practical acoustic characteristics, and the results can satisfy the simulation requirements.

Mechanism and Measures of Passive Homing False Alarm for Torpedo

CHAO Xiang-sheng, LEI Jiang-tao, ZHOU Hua, ZHANG Guo-feng

2009, 17(5): 040-43. doi: 10.11993/j.issn.1673-1948.2009.05.009

[Abstract](2090) [PDF 399KB](681)

Abstract:
To solve passive homing false alarm problem occurred in sea trial of torpedo, we analyze the mechanism of the false alarm through a large number of tests, understand that the false alarm results from the electrical noises generated by motor during torpedo passive homing. The electrical noise passes through electric power supply channel of transmitter to receive channel via acoustic coupling device, resulting in the false alarm. According to the analysis, we suggest such measures as switching off the transmitter power during passive homing period so as to filter out the electrical interference and to keep normal homing function. The test results show that the measures can effectively inhibit passive homing false alarm.

A Method of High Speed Moving Target Detection in Reverberation

LIANG Hong, LIU Jin-bo

2009, 17(5): 044-47. doi: 10.11993/j.issn.1673-1948.2009.05.010

[Abstract](2323) [PDF 476KB](1040)

Abstract:
Based on the fact that linear frequency-modulated (LFM) signal has a good focusing property in fractional Fourier transform(FRFT) domain, a moving target detection method in the presence of reverberation is presented using FRFT combined with fourth-order mixed cumulant slice (FRFT-FOMCS). Some details for designing the FOMCS based on FRFT are discussed. The present FRFT-FOMCS algorithm is more suitable for detecting LFM signals than the FRFT algorithm. Simulation results show that the FRFT-FOMCS algorithm can effectively detect and identify high speed moving target echo in reverberation.

Application of Sigma-Point Filtering to GPS/INS Integrated Navigation System with Simulation

ZHOU Lei, XU De-Min, GONG Cheng

2009, 17(5): 048-52. doi: 10.11993/j.issn.1673-1948.2009.05.011

[Abstract](1951) [PDF 492KB](679)

Abstract:
A new fusion algorithm of the measurements from global positioning system(GPS) and inertial navigation system(INS)is presented to compensate the weaknesses of current integrated navigation system. The extended Kalman filtering (EKF), an algorithm commonly used in integrated navigation system is a suboptimal one in a sense because it simplifies the nonlinear dynamic system model to a first order linear model and assumes that the linearized one is driven by Gaussian white noise. This simplification leads to questionable results in certain scenarios. One of the improved versions of EKF is sigma-point Kalman filtering (SPKF). SPKF needn′t assume a linearized dynamic model, and uses samples set to represent the state distribution, leading itself an adequate candidate for navigation applications. One of the good features of SPKF is that the states′ mean and covariance can be easily obtained. For Gaussian random variables, the mean and covariance can accurately approximate to at least second-order in any nonlinear system. Simulation results show that SPKF works well in GPS/INS integrated navigation system.

Compensation Method of Temperature Error for Laser Gyro

LIU Ming-yong, ZHOU Liang-rong, ZHAO Tao

2009, 17(5): 053-57. doi: 10.11993/j.issn.1673-1948.2009.05.012

[Abstract](1948) [PDF 541KB](721)

Abstract:
To reduce and compensate the influence of temperature on ring laser gyro(RLG) bias error and attain the precision of inertial level gyro, the mechanism of RLG zero-bias error due to temperature is analyzed. Based on a great number of environmental temperature experiments of RLG, a general temperature compensating model and a new kind of BP neural network model are established. A method for identifying the model parameter is proposed. Simulation results show that the simplified compensating model can reduce the zero-bias by more than a magnitude and achieve real-time compensating feature.

Modeling and Simulation of Inner Efficiency in Non-Design Condition for Torpedo Turbine

HAN Yong-jun, YANG Cheng-shi, PENG Bo

2009, 17(5): 058-62. doi: 10.11993/j.issn.1673-1948.2009.05.013

[Abstract](1876) [PDF 486KB](796)

Abstract:
In the existing simulations of torpedo turbine in non-design condition, a data fitting method was adopted in calculating inner efficiency of a torpedo turbine. We establish a set of models of inner efficiency in non-design condition for the turbine by combining theoretical analysis and empirical formula, perform a simulation, and obtain the variations of inner efficiency and the factors affecting inner efficiency. Simulation results show that the velocity coefficients of nozzle and working vanes are the key factors influencing inner efficiency. Comparison between simulation and test data verifies correctness of the proposed models.

Experimental Technology for Investigating Tail Jet Influence on Supercavitation Flow

LIU Tong-jun, LUO Kai, XU Yin

2009, 17(5): 063-66. doi: 10.11993/j.issn.1673-1948.2009.05.014

[Abstract](1997) [PDF 659KB](704)

Abstract:
We investigate an experimental method for analyzing the influence of tail jet on the ventilated supercavitation flow field of underwater vehicle. A similarity criterion for water tunnel experiment of tail jet is derived, which can help to set parameters of tail jet intensity. Numerical simulations of support mode to model are performed, and the results indicate that the head support mode is more suitable than the abdominal mode for this experiment. Water tunnel tests verify the reasonableness of the previous numerical simulations. Therefore, experimental study method about tail jet of supercavitating vehicle is understood.

Simulation of Weapon Underwater Launching with Computational Fluid Dynamics Software

ZHANG Hua-dong, ZHAO Guo-hua, ZHANG Xiao-fang

2009, 17(5): 067-71. doi: 10.11993/j.issn.1673-1948.2009.05.015

[Abstract](2056) [PDF 561KB](783)

Abstract:
To investigate the characteristics of water flow field and the pressure variation on weapon surface in process of weapon underwater launching, a flow field numerical simulation is performed using the commercially available computational fluid dynamics(CFD)software FLUENT based on the Reynolds averaged Navier-Stokes equations and k-ε turbulence model. Two-dimensional axisymmetric model is used in the simulation, and the inlet pressure boundary condition is set using the experimental data. Dynamic mesh method is adopted to solve the relative movement of the weapon in tube. The characteristics of launching flow field and the pressure distribution on weapon surface are thus obtained. The simulation results agree well with the moving velocity and displacement measured in launch trial. Therefore, the simulation may be regarded as an assistant tool in the optimization design of weapon and launch tube.

Attack Error Analysis of Helicopter′s Torpedo Guided by Surface Ship

E Qun, MA Yuan-liang, LIU De-cai, ZHOU Ming

2009, 17(5): 072-76. doi: 10.11993/j.issn.1673-1948.2009.05.016

[Abstract](1652) [PDF 483KB](681)

Abstract:
In the anti-submarine warfare (ASW) scenario, the errors of a helicopter′s torpedo guided by surface ship concerns guiding ship′s position error, course error, velocity error, detecting distance error, and detecting bearing error, as well as helicopter′s position error, attack course error, and attack velocity error. By analyzing transferring process of the above errors, we calculate the influences of these errors on attacking effect by using Monte Carlo method, and conclude that the navigating and positioning precisions of the guiding and attacking platforms impose significant influence on torpedo attacking effect.

Optimization Method of Aiming Point for Wake Homing Torpedo

LUO Di, LI Beng-chang, HENG Hui, ZHANG Jing-kang, ZHANG Ping-guo

2009, 17(5): 077-80. doi: 10.11993/j.issn.1673-1948.2009.05.017

[Abstract](1953) [PDF 450KB](692)

Abstract:
To satisfy the special demand of wake homing torpedo for aiming point, we simulate and analyze the existing selective method of shooting aiming point for wake homing torpedo according to the relevant control models of shooting and guiding wake homing torpedo and torpedo trajectory. Target velocity is found the major parameter in selection of aiming point, instead of the mid-point of target wake in all conditions. Selection of proper aiming point must take account of both the least consumption of torpedo range and the highest probability of torpedo′s entering target wake. A practical method for determining aiming point for wake homing torpedo is hence proposed.

2009 Vol. 17, No. 5

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