水下无人系统学报

Analysis of Technical Features of Supercavitating Torpedoes

WANG Gai-di

2007, 15(5): 001-4. doi: 10.11993/j.issn.1673-1948.2007.05.001

[Abstract](2431) [PDF 908KB](1238)

Abstract:
This paper briefly introduces the current development of supercavitating torpedoes in the world,and explains some confusable terms,including cavity,supercavitation,natural supercavitation,air supercavitation and cavity number.The focus is on the supercavitation forming mechanism and five characteristics,and the technical features of supercavitating torpedo,including overall structure and performance,propulsion,control unit and trajectory mode.The differences between supercavitating torpedo and conventional torpedo in structural shape,hydrodynamic distribution,system constitution and working property are summarized.

Research and Application of Super-corroding Alloys

XI Yu-lin, CHEN Pai-ming, WU Shi-Dong

2007, 15(5): 005-7. doi: 10.11993/j.issn.1673-1948.2007.05.002

[Abstract](1558) [PDF 879KB](707)

Abstract:
A new kind of magnesium alloys has been synthesized by high energy ball-milling of Mg and Fe mixed powders.Due to the high corrosion speed and reacting efficiency,the alloys are generally called super-corroding alloys (SCA).A SCA bulk is fabricated through cold-pressing and sintering the mechanically alloyed Mg-Fe powders.The chemical reaction of SCA with seawater rapidly releases heat and hydrogen gas,which may play very important roles in many ocean applications.For example,the reaction heat can be used to keep diver clothes warm;SCA corrosive links with the function of self-destruction can be utilized to control the sinking and floating of sonobuoy, and to salvage the training torpedo or other instruments.In addition,the reaction heat of SCA can be applied to heat food,machinery and ice or snow,which is thus very helpful for mountaineers.This paper summarizes the overseas and domestic development of SCA,and aims at accelerating its research and application in China.

6σ Robust Optimization Design for Wedge Ring Connection Structure of Torpedo

SONG Bao-wei, LIU Xu-lin, WANG Peng

2007, 15(5): 008-10. doi: 10.11993/j.issn.1673-1948.2007.05.003

[Abstract](1563) [PDF 675KB](879)

Abstract:
The main problems in optimization design include unsuitable initial value selection,circumstance interferences and random fluctuation of variables,which make the quality of product unstable.Robust design is a useful way to make quality of product insensitive to these factors.Combing the 6σ concept with sequential quadratic programming,this paper established a 6σ robust optimization design method,which not only searches the optimum results for the design object,but also improves the robustness and reliability of a product.Taking the design of the wedge ring connection structure of torpedo as an example,the presented method was used to obtain better optimum solution than the one with the deterministic optimization method.

Countermeasure and Counter-Countermeasure Between Surface Ship and Wake Homing Torpedo

ZHU Bang-yuan

2007, 15(5): 011-14. doi: 10.11993/j.issn.1673-1948.2007.05.004

[Abstract](1853) [PDF 869KB](1080)

Abstract:
The countermeasures of surface ship is based on ship wake signature suppression or making false wakes. Ship wake signature suppression includes wake bubble coalescing and wake energy absorbing. For producing a good degree of bubble coalescence, ultrasonic transducer (or array) must be towed to the join region of the bow wake, the turbulent boundary layer wake, and the initial spreading end of the propeller wake. Wake energy absorber mounted on the ship aft of the propulsor weakens the wake and renders the wake less pronounced acoustically. These two methods reduce the quantity of microbubbles in the wakes, so current wake-homing torpedoes are not able to counter these measures. Nevertheless, the wake homing torpedoes can be able to recognize actual wakes and false wakes. By estimating the average values of instantaneous frequencies of wake echoes, the actual wake of a ship and the false wake of a decoy can be identified based on the difference between motion properties of real wake bubbles and false wake bubbles. Two principles of trajectory design for anti-false wake are suggested.

Wavelet Denoising of Torpedo Fuze Target Signal

CHEN Guang, REN Zhi-Liang, LI Yao-Bo, YU Wei

2007, 15(5): 015-19. doi: 10.11993/j.issn.1673-1948.2007.05.005

[Abstract](1457) [PDF 856KB](844)

Abstract:
The denoising of torpedo fuze target signal is important for fuze reliable action.The conventional band pass filter has a low denoising precision and a poor waveform stability,whilst wavelet transform has a good feature in the denoising of a signal via decomposing a signal into different frequency bands with different scale parameters.Based on the typical models of torpedo electromagnetic fuze and magnetic fuze target signal,the wavelet denoising of the fuze target signal under a complex background noise is conducted by using wavelet transform,and a simulation of the denoising results with MATLAB is performed.The simulation graphs show that the wavelet denoising method has high precision,good adaptability and small waveform distortion compared with the conventional denoising means,so it is effective for eliminating background noises in torpedo fuze target signal.

Collaborative Optimization and Its Application to Multidisciplinary Design Optimization of Torpedo General Design

ZHANG Xue-feng, PAN Guang, WANG Peng

2007, 15(5): 020-23. doi: 10.11993/j.issn.1673-1948.2007.05.006

[Abstract](1906) [PDF 809KB](815)

Abstract:
Based on the response surface approximation collaborative optimization (RSACO) , an effective method for complex systems design, we divided the general design of torpedo into nine disciplines such as shape design, structure design, trajectory design, etc. The coupling connection among disciplines was discussed, and a multidisciplinary design optimization (MDO) mathematic model based on RSACO of torpedo general design was established. The results of an example of torpedo general design demonstrate that RSACO is a fast and efficient method to solve the complicated coupling relations in MDO of torpedo general design. The proposed method can improve the torpedo quality, avoid the waste of resources and reduce the design risk.

Design of Base Trajectory for Rocket Assisted Torpedo

ZHANG Bao-an

2007, 15(5): 024-28. doi: 10.11993/j.issn.1673-1948.2007.05.007

[Abstract](1847) [PDF 997KB](829)

Abstract:
To improve both security and fall point precision of air guidance trajectory of a rocket assisted torpedo with a main engine of solid rocket, an approach to ensure the safest glide trajectory is proposed by solving the intersection set of design field of glide trajectory under different conditions and taking the relative distance between the glide trajectory and intersection set edge as a parameter. A guidance scheme adopting dynamic base trajectory during glide and variable separation point of torpedo and rocket is presented. The guidance system calculates guidance trajectory through programmed interpolation during the torpedo rocketing into the air, and corrects the trajectory towards the safest glide trajectory. The scatter scope of separation points of torpedo and rocket can be narrowed obviously when the height of separation point is adjusted with speed at the end of the trajectory. The results show that the security can be improved as the base trajectory is solved in the intersection set. Dynamic base trajectory may enhance the tolerance of trajectory error and target correction, which helps to overcome the interference of strong wind field.

Design and Implementation of Integrated Navigation Simulation System for Autonomous Underwater Vehicle

LU Shu-juan, YAO Yao, LI Hui-ping

2007, 15(5): 029-32. doi: 10.11993/j.issn.1673-1948.2007.05.008

[Abstract](2166) [PDF 834KB](1038)

Abstract:
The real-time strapdown inertial navigation system/doppler velocity log(SINS/DVL) integrated navigation system of autonomous underwater vehicle(AUV) was developed and the design scheme for the system was proposed based on PC104 computer, including the basic software and hardware configurations. The hardware choosing, AUV model, integrated navigation system, and communication between each module were emphasized. The navigation system was designed by setting up a model of AUV, hence the experimental cost and the debugging time were greatly reduced. Simulation results indicate that the navigation algorithm and AUV model are correct; the precision in computation can meet the requirements. Therefore, this navigation system can be used to test and analyze the performance of AUV, and to ensure the location of AUV by navigation.

Influence of Water Conditions on Torpedo Acoustic Homing Range

HE Xin-yi, QIAN Dong, WANG Guang-yu, QU Da-wei

2007, 15(5): 033-36. doi: 10.11993/j.issn.1673-1948.2007.05.009

[Abstract](2056) [PDF 891KB](996)

Abstract:
Aiming at forecasting the torpedo acoustic homing range for actual targets under real water conditions, this paper summarizes the typical water conditions in different sea spaces and seasons, presents a forecast method of torpedo acoustic homing range, and establishes a transmission loss forecast model based on the ray acoustic theory and a reverberation level forecast model based on the cell scattering model. According to the technical parameters of acoustic homing torpedo, the torpedo acoustic homing range of actual targets under real water conditions is forecasted with the grid search technique. This paper also proposes some suggestions for commanders to attack targets with torpedoes.

Motion Characteristics on Vertical Plane of Superspeed Underwater Vehicle

LUO Kai, DANG Jian-jun, WANG Yu-cai, ZHANG Yu-wen

2007, 15(5): 037-40. doi: 10.11993/j.issn.1673-1948.2007.05.010

[Abstract](1933) [PDF 782KB](791)

Abstract:
When a superspeed underwater vehicle runs in cruise phase, its motion mode is different from that of a usual bedewed vehicle because a majority of its surface is surrounded by supercavitation. Therefore, its motion characteristics are unique. In order to control the depth and the attitude of this kind of superspeed underwater vehicle, it is necessary to investigate the motion characteristics of the vehicle on a vertical plane. This paper analyzed the hydrodynamic characteristics of the vehicle based on the hydrodynamic mechanism, and established a motion model of the vehicle on a vertical plane. It also analyzed the motion characteristics with lack of damp, and presented a key problem that the attack angle is not allowed to exceed the bound in control process. It was suggested that the control force should not be too violent. The research may be useful for designing the control system of a superspeed underwater vehicle.

Application of Neural Network to Torque Identification of Torpedo AC Motor

HAN Qi-yang, HOU Chu-lin

2007, 15(5): 041-43. doi: 10.11993/j.issn.1673-1948.2007.05.011

[Abstract](1901) [PDF 664KB](906)

Abstract:
Because the conventional torque control method can not be used to build up an accurate mathematical model,in order to improve the efficiency and reliability of online parameter identification for torpedo asynchronous motor,a method for identifying the torque of a torpedo AC motor based on back propagation (BP) neural network is presented to meet the requirement of system performance. An equation of AC motor torque is derived on hypothesis,and the torque is identified by the BP neural network trained online or offline, without the need for a mathematical model of target.The training results are used to design the identifying system.The simulation results show better accuracy of the torque identification with the proposed method.

Reliability Evaluation and Test of Embedded Software for Military Products

ZHOU Hua, LIU Jian-bing, YANG Jin-hou, TANG Heng

2007, 15(5): 044-47. doi: 10.11993/j.issn.1673-1948.2007.05.012

[Abstract](1780) [PDF 897KB](943)

Abstract:
Software reliability is one of the important indexes to evaluate the quality of software. The evaluation and test is a key method to obtain the quantificational index of software reliability. To reasonably and effectively acquire the data of software reliability is of great significance to evaluate the quality of software. Based on the developing process of embedded software for some military products, the overall evaluation process of software reliability is analyzed. In the iterative course of "test-check-new edition" , the test method of software load and press and the statistic technique of reliability are applied to track the change of fault intensity, and to gather and analyze the software fault data, and subsequently to evaluate software reliability. Finally, the software test and the software reliability test are contrasted to put forward the emphasis of each test. The evaluation and test of software reliability improve system reliability before the software product is applied or loaded into hardware, which provide sufficient guarantee to the reliability of military products.

A Signal Detection Algorithm Based on Fourth-order Cumulant

LIANG Hong, YANG Chang-sheng

2007, 15(5): 048-50. doi: 10.11993/j.issn.1673-1948.2007.05.013

[Abstract](1331) [PDF 706KB](823)

Abstract:
Aiming at the detection of the symmetric distributed non-Gaussian and CW signals in additive Gaussian noise, this paper proposes a detection algorithm which taking the absolute value of zeroth lag of the fourth-order cumulant from the matched filter (MF) output as a testing statistical data,derives the expressions of detection probability and false alarm probability,and introduces the test property of the algorithm.Theoretical analysis and simulation results confirm that the proposed algorithm performs better than the matched filter under Gaussian colored noise.

Judgement and Analysis Software of Simulation Data Based on C/S Frame for Acoustic Guidance System

ZHENG Wei, YIN Zong-hui

2007, 15(5): 051-54. doi: 10.11993/j.issn.1673-1948.2007.05.014

[Abstract](1597) [PDF 1023KB](801)

Abstract:
Aiming at the characteristic of acoustic guidance system simulation,a judgement and analysis software of simulation data is developed based on C/S frame using Web and database techniques,the administrative levels and their relationship as well as the database are set up,and all kinds of field information and status-data of the simulation system are centralized and managed in a server.The software offers the means of process and analysis, obtains the correlation and statistical analyses,supports the correlation between the analytical results and the related data in database, and outputs the results in the form of graph or document.The functions and design ideas of the software are introduced.In the process of implementing, the correlated data in one data file is defined as a "aggregate" type,the dataset of PL/SQL is set up to manage the data.Meanwhile,for all kinds of data files and multi-state data such as method and model,the relative fields of the dataset are defined as "Blob" type (in order) to treat them as an object.So the simulation data can be accessed, processed,analyzed and judged on a client.

Simulation Analysis of Countermeasure Effect of Noise Jammer in Submarine on Active Acoustic Homing Torpedo

HU Yan-feng, ZHENG Yuan, SHAN Guang-chao

2007, 15(5): 055-57. doi: 10.11993/j.issn.1673-1948.2007.05.015

[Abstract](2416) [PDF 728KB](1279)

Abstract:
Aiming at the interferences with and without noise jammer,this paper established a detect model for active acoustic homing torpedo based on the active sonar equation,obtained the detect ranges of torpedo active acoustic homing under the different sea states, submarine board angles and torpedo running depths.Then the law of the detect distance of torpedo active acoustic homing and the effect of noise jammer varying with sea state,submarine board angle and torpedo running depth are analyzed taking the average reduced-quantity and the average reduced-rate of torpedo homing detect range as criteria.The acoustic countermeasure (ACM) effect of noise jammer is evaluated through computer simulation.The simulation results could be helpful in submarine tactics research on the use of noise jammer to counter active homing torpedo.

Collisions and Countermeasures of Salvo Wake Homing Torpedo During Training

QIAN Zhong-ming, WANG Xing-jun

2007, 15(5): 058-60. doi: 10.11993/j.issn.1673-1948.2007.05.016

[Abstract](1912) [PDF 678KB](1023)

Abstract:
To meet the need of submarine unit training,this paper,based on distribution of torpedo, analyses three conditions which cause torpedo collision,i.e.the collision before torpedoes entering into wake,the collision of torpedo and target ship when torpedo passing by the target ship, and the collision after two torpedoes entering into target wake during salvo shot.Moreover,some methods are proposed to avoid collision during two torpedoes salvo shot,in which a range of exercise torpedo is set for one of the torpedoes to avoid their intersection,two different sea states are set for two torpedoes to keep running at different depths,or two torpedoes are fired toward opposite directions.These methods are easy to use and can provide effective guarantee for safe training of wake homing torpedo.

2007 Vol. 15, No. 5

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