水下无人系统学报

Water-Entry Impact Performance of Torpedo′s Cushion Nose Cap

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

2012, 20(3): 161-165. doi: 10.11993/j.issn.1673-1948.2012.03.001

[Abstract](1583) [PDF 465KB](823)

Abstract:
To solve the problems that theoretical analysis of water-entry impact process of torpedo′s cushion nose cap is difficult and strength design boundary of the nose cap is not easy to be determined, we build a finite element model of the nose cap water-entry with the software ABAQUS, and analyze the stress distribution of the nose cap assembly during water-entry impact process. The conclusion is drawn that vertical water-entry with minimum velocity is the most safe condition for the nose cap. Taking this condition as the upper limit of the nose cap strength design, key factors that may induce nose cap crack are analyzed. Accordingly, two methods to make the nose cap easy to crack after water-entry are offered, i.e. weakening the strength of the fairing and reducing the friction between the nose cap assembly and torpedo. Simulation results show that combination of two methods can achieve perfect nose cap water-entry.

Air Trajectory Design and Analysis for Mine Water-exit Attack

LI Yu-tian, ZHANG Yu-wen, ZHANG Ji-hua, LIU Li-dong

2012, 20(3): 166-170. doi: 10.11993/j.issn.1673-1948.2012.03.002

[Abstract](1781) [PDF 245KB](548)

Abstract:
The air trajectory was designed for a mine water-exit attack, and a mathematic model of attack trajectory was established. The attitude stabilization control for vertically upward trajectory, the restriction of turn angular rate, the setting of dive angle for fast turn trajectory, and the guidance of dive attack trajectory were analyzed. In addition, the dynamic characteristic of each trajectory was simulated, and the results show that the preset trajectory is stable and con-trollable, and can be used to accurately strike target.

Modeling and Simulation of Airdrop Mine Safety

LIANG Jing

2012, 20(3): 171-174. doi: 10.11993/j.issn.1673-1948.2012.03.003

[Abstract](1506) [PDF 199KB](569)

Abstract:
This paper establishes a motion equation and a mathematical model of airdrop process of a mine to verify the airdrop safety. Three situations are simulated, i.e. the situation before parachute-opening, the situation after para-chute-opening, and the situation of accidental parachute-opening. Simulation result shows that airdrop security of the mine can be ensured for the three situations. The following sea trial verifies the correctness of the proposed model and the simulation analysis.

Design of Multi-channel Sonar Signal Preprocessing System

DAI Ming-qing, FENG Xi-an, GAO Tian-de, LI Xiao-hua

2012, 20(3): 175-179. doi: 10.11993/j.issn.1673-1948.2012.03.004

[Abstract](1488) [PDF 302KB](645)

Abstract:
Analog preprocessing system is one of the key components of sonar receiver. A multi-channel analog pre-processing system is designed with high precision to process weak and variable sonar echo signals. The block diagram of the system is given, its working principle is analyzed, and each circuit is discussed. A voltage-controlled amplifier VCA810 is applied to the automatic gain control (AGC) circuit of underwater acoustic signals, achieving a constant and undistorted output for the input signals in the range of 40 dB to 40 dB. The system employs switched capacitor filters for wide band filtering, and the band width can be changed flexibly by dial switch. Experimental result shows that the proposed system meets the design requirements with the features of small size, low noise, low power consumption, and large dynamic range.

Anti-interference Method for Torpedo Passive Target Detection with Blind Source Separation

ZHAO Wei, HAO Bao-an, YANG Xiang-feng, XIAO Lin

2012, 20(3): 180-186. doi: 10.11993/j.issn.1673-1948.2012.03.005

[Abstract](1448) [PDF 346KB](686)

Abstract:
Enhancement of ocean environment noise level, improvements in target noise elimination and acoustic counter-measure bring great challenge to the torpedo passive target detection. To suppress interference in torpedo passive detection, we adopt the developing blind source separation (BSS) technique to separate interference from target signal by using independ-ence principle of target and interference, thus realize passive target detection in the condition of strong inference. We generate target radiation signal, simulated radiation noise, impulse and chirp interferences, then set up multi-interference noisy mixed model, and then adopt the four kinds of complex BSS algorithms to simulate interference suppression in passive target detec-tion. Simulation results show that BSS passive detection can effectively realize multi-interference separation, enhance signal to interference ratio (SIR), and improve passive target detection performance.

Bistatic Sonar Localization Algorithm Based on Nonlinear Least Squares

WANG Xin, ZHANG Guang-bin

2012, 20(3): 187-189. doi: 10.11993/j.issn.1673-1948.2012.03.006

[Abstract](1607) [PDF 197KB](602)

Abstract:
To improve bistatic sonar localization accuracy, a nonlinear least squares(NLS) localization algorithm based on Levenberg-Marquardt-Fletcher(LMF) method for bistatic sonar is proposed. The localization principle and the geo-metrical dilution of precision(GDOP) of localization error are analyzed, and the localization error distribution is ob-tained. Through numerical simulation, localization accuracy for different baseline length is investigated. And the local-ization accuracy of NLS algorithm is compared with that of the time-only-localization(TOL) method. Simulation results show that NLS algorithm, which takes full advantage of system information, has higher localization accuracy than TOL method, especially, its localization accuracy can be improved by 30% under shorter baseline length of 7.4 km.

High-Resolution DOA Estimation Algorithm for Underwater Target Echo Highlight with Simulation

XU Yu, TANG Bo, YUAN Bing-cheng

2012, 20(3): 190-194. doi: 10.11993/j.issn.1673-1948.2012.03.007

[Abstract](1478) [PDF 222KB](549)

Abstract:
Underwater target echo highlight identification technology is a very important part for modern sonar system and underwater acoustic countermeasure. However, when transmit signal is long pulse or the sonar system is located at abeam bearing, the estimation algorithm of underwater target echo highlight direction of arrival(DOA) based on sin-gle-source based short pulse split theory is inefficient. Therefore, a multi-source based high-resolution DOA algorithm for underwater target echo highlight is proposed in this paper. The received echo signal is de-correlated and the echo highlight number is estimated by the Gerschgorin radii-based estimator based on the reverse conjugate array, and then the underwater target echo highlight direction is estimated with the space spectrum estimation method. Moreover, un-derwater target echo is simulated with the planar element method for high-resolution DOA estimation. Simulation veri-fies the proposed method is efficient for recognition of submarine target at abeam bearing.

Application of Disturbance Observer to Stabilization Loop in Inertial Platform

WANG Chen-chen, WANG Xin-long, Huang Hai

2012, 20(3): 195-200. doi: 10.11993/j.issn.1673-1948.2012.03.008

[Abstract](913) [PDF 259KB](557)

Abstract:
Torques of friction and other disturbance counteract the performance improvement of the stabilization loop in iner-tial stable platform. To overcome these torques, a method utilizing disturbance observer to inhibit the disturbance torques is proposed on the basis of the traditional proportion-integration-differentiation (PID) control method. The disturbance observer is composed of the torque current and angular velocity. Simulation results show that introduction of the disturbance observer effectively inhibits the disturbance torques without influencing the dynamic performance of the original PID controlled stabi-lization loop and, hence enhances the accuracy and disturbance-inhibition capability of the stabilization loop.

Error Estimation Method of SINS with Large Attitude Error Angle Based on Underwater Terrain Matching

LI Heng, SHEN Jian, LUO Xuan, ZHANG Jing-yuan

2012, 20(3): 201-205. doi: 10.11993/j.issn.1673-1948.2012.03.009

[Abstract](1446) [PDF 388KB](547)

Abstract:
Conventional error estimation method based on linear filtering adopts the angle method-based linear error model of strapdown inertial navigation system (SINS). However, its estimation is unstable and inaccurate when attitude error angle is large. Therefore, we propose a new error estimation method based on unscented Kalman filter(UKF). By building a nonlinear error model of navigation system with underwater terrain matching and taking terrain matching, position and depth measured by depth-pressure sensor as the measured quantities, we design a state-extended UKF for error estimation. Simulation results indicate that our method achieves better navigation error estimation for large attitude error angles.

Detection System of Component Content for Torpedo Fuel Based on NIR

LI Wei, JU Jun-jiang, DENG Peng

2012, 20(3): 206-209. doi: 10.11993/j.issn.1673-1948.2012.03.010

[Abstract](915) [PDF 221KB](695)

Abstract:
This paper analyzes the problems in detecting component content of torpedo fuel with the existing methods. Based on chemometrics and spectral theory, a method for detecting component content of torpedo fuel with near infrared (NIR) spectroscopy is proposed. By selecting modeling sample set, restoring weak NIR signal, and establishing and optimizing near infrared mathematical model, an NIR analysis system of component content for torpedo fuel is devel-oped. With this system and related method, the torpedo fuel samples of different batches and storage states are examined and the components are detected, and the results are compared with the test data from the existing methods. The com-parison verifies the accuracy and feasibility of the proposed detection system. Thus, long-range on-line analysis, mobile analysis on vehicle and emergency analysis on-the-spot are realized with this method.

Stepless Speed Turbine System Based on Variable Flow Pump and Nozzles

ZHAO Kuan-ming, YANG Cheng-shi, LU Kai, QIAN Zhi-bo, ZHU Yun-jin

2012, 20(3): 210-214. doi: 10.11993/j.issn.1673-1948.2012.03.011

[Abstract](1015) [PDF 255KB](1181)

Abstract:
For the low energy transformation efficiency of the turbine system controlled by single variable flow rate, a bi-variable control method combining open-loop control of working nozzle number and closed-loop control of variable flow rate of fuel pump is proposed to realize stepless speed control of turbine engine. An improved adaptive control algorithm is used for the closed-loop control. This bi-variable control method is simple and suitable for anti-ship and anti-submarine autonomous underwater vehicles, and can make the turbine system work with high efficiency and stabil-ity. Simulation result indicates that the turbine system with the bi-variable control achieves lower fluctuation in both pressure and speed, and obtains a 28% reduction in fuel consumption of the system and a 230 K decrease in temperature of foreside of turbine vane, compared with the turbine system with single variable control.

Preliminary Exploration on Launch Modes of U.S. Submarine Torpedo Launchers

ZHU Qing-hao, SONG Ru-gang

2012, 20(3): 215-219. doi: 10.11993/j.issn.1673-1948.2012.03.012

[Abstract](1883) [PDF 220KB](940)

Abstract:
Aiming at the tactical needs for covertly launching torpedoes in the future of antisubmarine warfare, and on the basis of analysis of the technological characteristics of the U.S. submarine torpedo launchers in commission and to be in commission, we sum up the tactical employment characteristics and occasions for different launch modes of the torpedo launchers, analyze the purposes of different launch modes, and offer some suggestions about the development and tactical employment of submarine torpedo launchers.

Simulation of Gas-water Recovery Process in Pneumatic Imbalanced Torpedo Launcher

LIAN Yong-qing, Zhou Hou-cheng, Wu Kai-feng, TIAN Bing

2012, 20(3): 220-224. doi: 10.11993/j.issn.1673-1948.2012.03.013

[Abstract](1323) [PDF 306KB](902)

Abstract:
The gas-water recovery process of non-bubble system has direct influence on the stealth and proportionality of the submarine as it launches a torpedo with pneumatic imbalanced torpedo launcher. To investigate the recovery process, mathematical models of this system are built about timing regulator, bubble-free air flask, relief valve, and so on, and the gas-water recovery process of the non-bubble system is simulated by combining with existing pneumatic imbalanced torpedo launcher models. Comparison of the simulation result with the practical recovery amount shows that the mathematical models are correct, and can be applied to design and analysis of the non-bubble system of pneumatic im-balanced torpedo launcher.

Attitude Simulation Method for Torpedo Pitch Angle at ±90°

HUANG Hua-hong, YANG Yun-chuan, Lü Yan-hui

2012, 20(3): 225-230. doi: 10.11993/j.issn.1673-1948.2012.03.014

[Abstract](1152) [PDF 437KB](681)

Abstract:
The pitch angles of rocket assisted torpedo, airdropped torpedo, homing mine and high altitude antisubmarine torpedo will get to ±90° when they are launched and move. At this time, the inner axis and outer axis of the vertical three-axis turntable coincide with each other to lose three-degree of freedom motion, resulting in difficulty in torpedo attitude simulation. By changing the installation mode of the sensing element and establishing corresponding driving equation of the three-axis turntable and transform formula of turntable angle and torpedo attitude angle, torpedo attitude simulation is realize when torpedo pitch angle gets to ±90°. Theoretical analysis and experiment verify the correctness and feasibility of the proposed method. Simulation results show that this method can be used for semi-hardware-in-loop simulation of rocket assisted torpedo in vertical launch and water-entry, and it can also be used for many moveable ob-jects with pitch angle ±90°.

Testing Scheme for Torpedo Hitting Accuracy

Zhu Wen-zhen, Ye Hao-liang, Li Guo-liang

2012, 20(3): 231-235. doi: 10.11993/j.issn.1673-1948.2012.03.015

[Abstract](1608) [PDF 248KB](624)

Abstract:
To construct a testing scheme for intelligent lightweight torpedo perpendicular hitting accuracy, we sum up four assessment methods based on existing test condition, and analyze the advantages and disadvantages of each method in cost and feasibility. For test evaluation, we determine an assessment method with combination of attacking submarine in single-plane and tracking/attacking fixed target in dual-plane, and correspondingly offer a test design method and a test evaluation method, in order to provide a basis for assessing intelligent lightweight torpedo hitting accuracy.

Bearing-only Target Motion Elements Solver Based on Reconfigurable Computing

SONG Huan-huan, WANG Shu-zong

2012, 20(3): 236-240. doi: 10.11993/j.issn.1673-1948.2012.03.016

[Abstract](984) [PDF 187KB](551)

Abstract:
Reaction time of submarine combat system depends on data processing technology used in target motion elements solver. Based on existing algorithms, reconfigurable computing system is taken as accelerator of target motion elements solver to analyze the input data stream of bearing-adjustment algorithm, and simplify scalar operation of sys-tolic array. Reconfigurable computing of bearing-adjustment algorithm is implemented by using pipeline parallel princi-ple. Experimental results verify that reconfigurable computing can accelerate execution speed of the algorithm.

2012 Vol. 20, No. 3

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