水下无人系统学报

R&D Strategy of Next Generation Electric Power Lightweight Torpedo in US Navy

QIAN Dong, CUI Li, XUE Meng

2007, 15(6): 001-4. doi: 10.11993/j.issn.1673-1948.2007.06.001

[Abstract](2396) [PDF 1000KB](1660)

Abstract:
Electrically powered torpedo has many advantages,such as low training cost,low noise,stealth,modularized battery and high reliability.Therefore,US Navy has begun to develop new generation of electrically powered lightweight torpedo in recent years,and some breakthrough has been achieved on the integrated motor propulsor (IMP)of electrically powered torpedo.This paper describes the research background and status quo of the torpedo,and analyses the advantages of IMP.On analyzing the research and development (R&D) strategy of the electrically powered lightweight torpedo in US Navy,it is suggested that different power technology should be traced and developed appropriately to keep continual competitive ability,operational adaptability and training cost of new weapon should be emphasized to enhance comprehensive benefit,R&D of weapon technology should be planned from the viewpoint of underwater equipment system,and universality of technology and product should be paid more attention.

Analysis of Construction Principle and Characteristics of Pump-Jet for Underwater Integrated Motor Propulsor

LIU Wen-feng, HU Yu-li

2007, 15(6): 005-8. doi: 10.11993/j.issn.1673-1948.2007.06.002

[Abstract](2625) [PDF 948KB](1479)

Abstract:
The mechanical structures, working principle and technology features of the pump-jet in a new underwater integrated motor propulsor(IMP) are described. The pump-jet has the advantages including high efficiency, limited noise, good manageability and adaptability in comparison with traditional propeller mode. Application of the pump-jet are prospected. Integrating a special motor, the pump-jet exhibits higher efficiency and small space, and can be used to unmanned undersea vehicle, lightweight torpedo, heavyweight torpedo, and submarine.

Target Detection Method of Underwater Acoustic Signals Based on Energy Entropy of Empirical Mode Decomposition

HU Qiao, HAO Bao-an, LV Lin-xia, CHEN Ya-lin, SUN Qi

2007, 15(6): 009-12. doi: 10.11993/j.issn.1673-1948.2007.06.003

[Abstract](2436) [PDF 826KB](1112)

Abstract:
In order to correctly detect the acoustic signals of underwater target in complicated environment, a novel target detection method of underwater acoustic signals based on energy entropy of empirical mode decomposition (EMD) is proposed, where these intrinsic mode components are decomposed via empirical mode decomposition from original signals and converted into energy feature vectors, and thus the energy features of sub-band frequency can be inspected. The energy entropy of EMD is obtained from these normalized energy feature vectors to detect the target of underwater acoustic signals. The proposed method is applied to the target detection of simulation signal and radiated noise data of underwater target. The experimental results show that this method can effectively obtain the energy feature of sub-band frequency, and greatly optimize the target detection threshold of underwater acoustic signals compared with the wavelet transform method.

Kinematics and Dynamics of Contrapositive Cam Engine

YUAN Peng, WANG De-shi, WANG Shu-zong

2007, 15(6): 013-16. doi: 10.11993/j.issn.1673-1948.2007.06.004

[Abstract](1910) [PDF 786KB](778)

Abstract:
Vector and coordinate transformation are used to analyse the work surface equation and the slip velocity between the cam and idler wheels, also the dynamic characteristics of pistons, cylinders and principal axis of the contrapositive cam engine. Compared with dissymmetrical engines, the results show that the contrapositive cam engine can balance the axial force with larger torque output and lower loads on shafting bearings. The kinematic and dynamic analysis indicates the scheme of contrapositive can engines is completely feasible.

Influence of Noise from Torpedo Electric Generator on Homing System and Countermeasures

CHEN Chun-yu, YI Hong, HAO Bao-an, WU Ya-jun

2007, 15(6): 017-19. doi: 10.11993/j.issn.1673-1948.2007.06.005

[Abstract](2162) [PDF 721KB](1097)

Abstract:
This paper discusses the influence of noise from an electric generator on torpedo self noise with regard to high noise of thermal power torpedo. The output noise of built-in power source is generated from the electric generator, and verified by spectrum analysis and analogue test. The noise enters the receiver from the converting circuit of homing receiver and transmitter through cables, ground wire and the homing transmitter. The characteristic of the noise and its influence mechanism on homing range are analyzed. The countermeasures to improve circuit design for receiving and transmitting isolation are proposed to enhance the ability of blocking noise and filtering power source. The test results show that the countermeasures can restrain the noise by 10dB to 20dB to increase the homing range to a new level, and reduce the probability of false alarm in passive homing to improve the performance of homing system and to increase the reliability of homing system operation.

Acoustic Passive Directional Method of Broadband Source Using Multiple Small Aperture Subarray

HE Hui-jiang, SU Shuai, SUN Chao

2007, 15(6): 020-25. doi: 10.11993/j.issn.1673-1948.2007.06.006

[Abstract](2180) [PDF 914KB](849)

Abstract:
An approach for the direction of arrival (DOA) estimation of multiple broadband sources was presented by using multiple small aperture subarrays, and a novel signal model used in rank reduction estimator (RARE) was used to deal with the information from multiple small aperture subarrays. Then approximate RARE estimator was built to estimate DOA of multiple broadband sources. Source resolution and directional precision were increased by extending array aperture. Moreover, false peak that appears in the conventional methods based on eigen subspace was removed from spatial spectrum effectively with the proposed method, and sensitivity to position error was reduced by robust RARE estimator. Simulative and experimental results show that the method achieves better statistical stability and lower threshold of signal to noise ratio(SNR). Correct DOA estimation can also be obtained in the case of large intersubarray displacement error.

Application of AUV/SINS Integrated Navigation System to Autonomous Underwater Vehicle(AUV)

SUN Can-long, ZHANG Yan, LI Hui

2007, 15(6): 025-27. doi: 10.11993/j.issn.1673-1948.2007.06.007

[Abstract](1001) [PDF 307KB](279)

Abstract:

Simulation of Relationship Between Directional Detonation Mode and Power Field for Underwater Warhead

LU Zhong-bao, NAN Chang-jiang

2007, 15(6): 028-31. doi: 10.11993/j.issn.1673-1948.2007.06.008

[Abstract](1665) [PDF 803KB](1110)

Abstract:
An underwater warhead with different directional detonation modes will produce different explode power field. In order to seek for a directional detonation mode which can achieve more directional energy gain and larger area of the gain, simulation models of an underwater explode warhead with different directional detonation modes are established with the simulation software AUTODYN, and the parameters of explode power field are calculated and comparatively analyzed. Then the relationship between directional detonation mode and explode power field of underwater warhead is obtained. According to the theoretic analysis and the practical use, a feasible and more excellent directional detonation mode is presented finally.

Analysis of Narrow Pulse and Ultra-wideband Signals Characteristic and Its Short-range Application

ZHANG Juan, WANG Xin-hong, CHEN Hang

2007, 15(6): 032-35. doi: 10.11993/j.issn.1673-1948.2007.06.009

[Abstract](1854) [PDF 816KB](792)

Abstract:
General torpedo homing signals are usually modulating wideband signals, which have some disadvantages in short-range detection to reduce the accuracy when a torpedo hits target. In order to make up the shortcomings, this paper analyses the characteristic of a narrow pulse and ultra-wideband homing signals, and compares it with linear frequency modulation(LFM) signals in resolution rate, measuring precision, Doppler velocity tolerance and so on. The results indicate that the narrow pulse and ultra-wideband signal gains higher resolution of distance, stronger ability of target identification and smaller homing blind area. Based on these features, a torpedo can continually track and accurately attack target on its terminal trajectory when the narrow and ultra-wideband signals is used in short-range detection. And at very short distance, the echo can also be used as fuze information to implement the integrated homing fuze design.

A Trusty Policy-Based Network Management Architecture with Mobile Agent Technology

HE Jing1., LI Meng

2007, 15(6): 036-39. doi: 10.11993/j.issn.1673-1948.2007.06.010

[Abstract](1511) [PDF 895KB](798)

Abstract:
With the development in the research on policy-based system, people have been interested extensively in the policy-based network management architecture with mobile agent (MA) technology. Hence the problem that the manager is suspicious of the policy and its execution becomes more outstanding. Therefore, this paper proposes a trusty policy-based network management architecture with MA technology by assigning the indexes to each policy and combining them with the reinforcement learning process. With this system the manager can trust the architecture and thus be released from the fussy operation.

Nonlinear Modelling of Control-Configured Underwater Vehicle in Complicated Oceanic Environment

GE Hui, YAN Wei-sheng, XU De-min

2007, 15(6): 040-45. doi: 10.11993/j.issn.1673-1948.2007.06.011

[Abstract](1749) [PDF 958KB](1163)

Abstract:
The new type of control-configured underwater vehicle is equipped with multi-thrusters on different directions to realize direct hydrodynamic lift control and direct hydrodynamic side force control in two motion modes of cruise and hover. Hydrodynamic models of different motion modes and models of oceanic environment including wave and current are established. Then nonlinear motion equations with six degrees of freedom of the vehicle are deduced based on the momentum theorem and the momentum moment theorem. Simulation results show that the proposed models can simulate the motion modes of cruise and hover, and describe low and high frequency motion states of underwater vehicle. These models will be useful for the control system design and simulation of underwater vehicle moving near sea surface.

Digital Simulation of Thermal Propulsion System for Autonomous Undersea Vehicle

NIE Wei-dong, QIAN Jian-ping, CHENG Wen-li, ZHAO Kuang-ming

2007, 15(6): 046-48. doi: 10.11993/j.issn.1673-1948.2007.06.012

[Abstract](2028) [PDF 860KB](913)

Abstract:
An efficient and modularized digital simulation software for designing and testing a novel thermal propulsion system of autonomous undersea vehicle(AUVTPS) was developed by using MATLAB/SIMULINK. The AUVTPS was simulated under different regimes of various work stages, and hence the simulation results can be analyzed including the transient characteristics of start process, changing speed process and changing depth process of AUVTPS. This simulation method overcomes the disadvantage of bed test which can only obtain steady characteristics of AUVTPS. The simulation software is used to aid the reliability design of AUVTPS and the robustness design of its control device. This method can be used for some functions of hardware-in-the-loop simulation and bed test, so that the design and development cost can be reduced.

Numerical Simulation of Influence of Tail Jet on Steady Supercavitation Configuration

DANG Jian-jun, LIU Tong-jun, XU Yin

2007, 15(6): 050-52. doi: 10.11993/j.issn.1673-1948.2007.06.013

[Abstract](1959) [PDF 783KB](926)

Abstract:
The influence of tail jet intensity on the steady supercavitating flow was analyzed, and a numerical investigation of the ventilated cavitation and tail jet flow field of a 2D underwater vehicle model was performed by using FLUENT. Several numerical simulation examples were given, and the simulation results indicate that when the flow velocity, environment pressure and ventilation condition remain unchanged, the geometrical shape of supercavity before it closes on the tail jet stream changes little with the increase in intensity of tail jet. The obtained law agrees with the results observed from the water tunnel test, which indicates the simulation model is valuable to engineering application and can be taken as a reference for designing hydrodynamic configuration of supercavitating vehicle.

Dynamic Scheduling Method for Fleet Cooperative Anti-Submarine Simulation System Based on Grid

FU Yan-fang, KANG Feng-ju, WEI Jia-ning

2007, 15(6): 053-57. doi: 10.11993/j.issn.1673-1948.2007.06.014

[Abstract](2086) [PDF 1021KB](782)

Abstract:
Aiming at how to balance load in grid environment, the dynamic scheduling of parallel tasks in entity level is investigated, and an improved threshold scheduling algorithm is presented for balancing load. The application of the algorithm to the fleet cooperative anti-submarine simulation system verifies its feasibility. This algorithm takes second optimal solution as goal to reduce executive expense of task. The method can enhance the efficiency of distributed interactive simulation and enlarge simulation scale.

Design and Test of Ignition for Underwater Solid Rocket Motor

ZOU De-rong, HUANG Liu-hua, CHEN Xiong-zhou

2007, 15(6): 058-61. doi: 10.11993/j.issn.1673-1948.2007.06.015

[Abstract](1710) [PDF 811KB](1092)

Abstract:
Ignition device with fireworks agent was designed using dual ignition cylinders for dual thrust underwater solid rocket motor(SRM). The ignition charge was obtained via theoretical calculation, estimation by empirical formula, similar SRM analog, and working condition revision. The tests for standard SRM in the range of 5～14 MPa, conformity of ignition, ignition cylinder, and full size SRM were performed. The results show that the ignition and the grain combustion are normal, the SRM starts timely, the curves of pressure-time and thrust-time are satisfying, the ignitions are in step. This ignition method is verified reasonable and valid.

2007 Vol. 15, No. 6

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