水下无人系统学报

Recent Development of Drag Reduction Technologies via Boundary Layer Control

GUO Jie, GENG Xing-guo, GAO Peng, OU Xiu-long

2008, 16(1): 001-6. doi: 10.11993/j.issn.1673-1948.2008.01.001

[Abstract](2584) [PDF 799KB](900)

Abstract:
The technology of drag reduction in ships and underwater vehicles is well concerned in recent years. One of the effective ways to reduce drag is to control the flow pattern at wall boundary layer. This paper sums up the current drag reduction technologies via boundary layer control in the world, introduces the research on drag reduction by riblets, compliant coating and hydrophobic coat, and analyzes their mechanisms. It also describes drag reduction by microbubbles, wall absorbing, and wall heating & cooling. Finally, it presents three suggestions as follows: making great effort to research drag reduction mechanism, integrating different methods of drag reduction, and combining theoretical research with engineering application.

A Method for Load Separation from Head of Autonomous Underwater Vehicle Using Load Gravity and Suitable Thrust

SONG Bao-wei, ZHAO E, SHAO Cheng, LI Jia-wang

2008, 16(1): 007-10. doi: 10.11993/j.issn.1673-1948.2008.01.002

[Abstract](2158) [PDF 451KB](1034)

Abstract:
Based on the given dynamic equations,a set of models of the initial position and initial attack angle of the separated load and the launcher of autonomous underwater vehicle (AUV) are deduced.A new load separation method using load gravity and suitable thrust is presented.Simulation results show that when the launcher speed is given,a certain increase of thrust will shorten separation time,reduce interaction of load and launcher,and hence improve separation safety.The safety of proposed method relates to the preset separated angle and the initial velocity.When the intial velocity reduces,the separation safety can be improved.When the initial velocity increases,the separation safety can be ensured by reducing the preset separated angle (no more than 90 degree).

Reliability Assessment Method for Varied Population Product

HUO Jun-long

2008, 16(1): 011-13. doi: 10.11993/j.issn.1673-1948.2008.01.003

[Abstract](1885) [PDF 296KB](598)

Abstract:
The various technology conditions exist in different phases of product development, therefore, the products can not be treated as a population and their test data also can not be simply added together in reliability assessment. Duo to the small amount of tests conducted, the value obtained in reliability assessment is usually smaller than the actual value. This paper integrates the reliability of each phase and builds up a mathematical model for assessment of reliability growth to derive the reliability assessment equations for qualified or unqualified product. This assessment method utilizes fully the trial information from every phase to reflect the reliability growth process in product development, and provides an effective means for evaluation of reliability examination on product with multiple design phases, varied population and less test data. Meanwhile, the method is used to calculate the real reliability level of a product. The conclusion shows that the assessment result is approximately the same as the reliability level that the product reaches.

Modeling and Simulation of Oblique Water-Entry of Disk Ogive

WANG Yong-hu, SHI Xiu-hua, WANG Peng, WANG Sheng-wu, ZHAO Jun-rong

2008, 16(1): 014-17. doi: 10.11993/j.issn.1673-1948.2008.01.004

[Abstract](1584) [PDF 427KB](797)

Abstract:
Based on water-entry dynamic and water-entry ballistic theories, the oblique water-entry process of disk ogive is simplified and a wetted correction factor is introduced in order to accord with the true water pile phenomena, and an oblique water-entry impact model coupled with ballistic and dynamic models are established. According to the exact geometric shape of the wetted body surface, the dynamic model is established. The coupling model of the oblique water-entry impact is programmed and calculated by the time stepping codes. The greatest impact load, the initial water-entry condition and the relation between water-entry impact loads are obtained. The influence of water pile on the oblique water-entry impace load are achieved. Finally, the varying rule between axial, vertical impace load and impact moment are analyzed to predict the phenomena of whip and ricochet or succedent underwater trajectory.

Passivity-Based Sliding Mode Control on Torpedo Nonlinear Attitude System

CHEN Ye, WANG De-shi

2008, 16(1): 018-20. doi: 10.11993/j.issn.1673-1948.2008.01.005

[Abstract](1612) [PDF 309KB](612)

Abstract:
A general Hamilton canonical form(GHCF) of torpedo nonlinear attitude system is established, and a control law is designed through combining passivity and sliding mode techniques, choosing the manifold of sliding mode separately. The whole nonlinear characteristics of the system are used in this method. The reachability of sliding mode is analyzed with passivity theory, and the stability of sliding mode enables to enhance the system performance. In simulation, the sliding mode control of torpedo nonlinear attitude system is realized, and the attitude angle is controlled well.

Simulation and Analysis of Upper Limit Control Rule for Torpedo

WANG Gai-di, SUN Hua

2008, 16(1): 021-24. doi: 10.11993/j.issn.1673-1948.2008.01.006

[Abstract](1506) [PDF 464KB](768)

Abstract:
Because bending and being tracked of sound line make torpedo tailing after target to smaller depth,upper limit control trajectory is usually considered in torpedo trajectory design.When torpedo arrives at the upper limit depth,upper limit control is performed compulsively,and then torpedo is pulled below the upper limit depth.The principle and trajectory feature of the upper limit control are analyzed,and the rule of upper limit control is presented.Moreover,the depth trajectories for torpedo to enter into the upper limit depth by three control modes during pursuing target are calculated and simulated.The results show that under the complicated upper limit control logic,the upper limit depth trajectory is not a simple form,but two or more irregular forms of re-entering into the upper limit depth,or regular oscillation form around the upper limit depth.These results may be expected to provide a theoretical basis for analyzing the problem in sea trial.

Depth Control of Superspeed Underwater Vehicle in Vertical Plane

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

2008, 16(1): 025-28. doi: 10.11993/j.issn.1673-1948.2008.01.007

[Abstract](2207) [PDF 401KB](704)

Abstract:
When a superspeed underwater vehicle runs in cruise phase, its motion characteristics are different from those of a usual bedewed vehicle because a majority of its surface is encircled by supercavitation. Based on the motion characteristics and the unique restricted condition of vehicle control in vertical plane, two depth control schemes adopting the ’bang-bang’ rudder operating control method were put forward. One is direct depth feedback control, and the other is indirect depth control via controlling the pitch angle feedback. The method of obtaining depth feedback signal was also discussed. These control methods are robust and easy to implement. The validity of these methods are verified by a mathematical simulation.

Anti-false Action Technology for Active Electromagnetic Fuze in Torpedo

Chen Chun-yu, Xiao Su-juan

2008, 16(1): 029-32. doi: 10.11993/j.issn.1673-1948.2008.01.008

[Abstract](2045) [PDF 519KB](794)

Abstract:
This paper analyzes the interference field which causes the false action of active electromagnetic fuze in torpedo, and identifies electromagnetic incompatibility inside torpedo and sailing vibration of torpedo as the key sources. Therefore, the requirements of counter-countermeasure design and safety design are put forward to optimize the anti-false action design. Test results show that the improved designs can effectively reduce the probability of false action and enhance the reliability of torpedo fuze action. Moreover,a method for calculating probability of false action is presented to examine anti-interference design of fuze.

Analysis and Solution of Passive Homing Problem for Lightweight Torpedo

LEI Jiang-tao, QU Da-wei, ZHOU Hua, WANG Yu, ZHANG Guo-feng

2008, 16(1): 033-35. doi: 10.11993/j.issn.1673-1948.2008.01.009

[Abstract](2214) [PDF 377KB](790)

Abstract:
To solve the problem that passive homing of lightweight torpedo can not pursue target in sea trial, the fault in sea trial and the torpedo performance were analyzed and compared. It was found that the built-in electric interfere and the abnormal opening of amplitude gate resulted in not pursuing target and losing target in the passive pursuing process. Therefore, such measures as adjusting the related coefficient of receiver, adding an inductance in power supply circuit of transmitter, and increasing the width of passive amplitude discrimination were taken. The trial results show that these measures can improve the function of passive detection to meet the requirements for passive homing pursuit and homing range, and can simultaneously improve active detection of homing torpedo.

Direction of Arrival Estimation for Coherent Distributed Target Sources

ZHOU Min

2008, 16(1): 036-39. doi: 10.11993/j.issn.1673-1948.2008.01.010

[Abstract](1735) [PDF 477KB](621)

Abstract:
The strong coherence between target sources leads to rank loss of covariance matrix of receiving data may, and hence cause incomplete target report. In order to estimate the direction of arrival (DOA) of coherent target sources and increase the estimation performance of the algorithm under low signal to noise ratio (SNR), an improved DOA estimation method of Toeplitz, namely, sub-spatial rebuild method is presented. The sampling matrix is treated by Toeplitz based on the method of dealing with dot target coherent distributed source, then the sub-spatial obtained after decomposing the characteristic of covariance matrix of receiving data is rebuilt, and the DOA estimation of coherent distributed source is dealt with effectively. Simulation results show that the method can improve the estimation performance of the algorithm under low SNR and estimate effectively coherent distributed source.

Comparison Between Two Electromagnets with Different Control Characteristics for Torpedo

GUO Ru-peng, LOU Jian-yong, HAN Xue-mei, SUN Kai-feng, ZHAO Kuan-ming

2008, 16(1): 040-43. doi: 10.11993/j.issn.1673-1948.2008.01.011

[Abstract](1613) [PDF 553KB](679)

Abstract:
In order to improve the performance and economy of electromagnetic valve, two electromagnets with constant voltage and vary voltage control for torpedo are investigated and compared. The structure and operating principle of the two electromagnets are discussed, and the control voltage, current, power and coil parameters of the electromagnets are analyzed using software ANSYS. The results show that the electromagnets with vary voltage control can reduce the volume of electromagnetic vavle and coil power loss, and promote the miniaturization of torpedo.

Numerical Simulation of Penetrating Simulant Targets of Submarine Structure by Explosively-formed Projectile of Torpedo Shaped Charge Warhead

WANG Tuan-meng, XIANG Chun

2008, 16(1): 044-47. doi: 10.11993/j.issn.1673-1948.2008.01.012

[Abstract](1650) [PDF 586KB](758)

Abstract:
The test of damage effect of the explosively-formed projectile(EFP) on submarine structure is of benefit to evaluate the damage power of anti-submarine torpedo shaped charge warhead. The varing law of the velocity and the acceleration of EFP during penetration processes are analyzed, and the damage effects of the stimulant targets of submarine structure are calculated by finite element analysis software ANSYS/LS-DYNA with ALE fluid-structure coupling algorithm. The EFP of 1.882 kg explosive warhead causes 49 mm crevasse on the simulant target of submarine pressure cabin after penetrating 650 mm simulant water cabin, and its still keeps the velocity of 131.5 m/s after penetrating 6 additional steel shells. Simulation results show that the model is reasonable, the algorithm is correct, and the damage effects are close to the experimental ones.

Battlefield Damage Level Assessment for Submarine Torpedo Weapon System Based on Evidential Reasoning Algorithm

ZUO Hao, MA Liang

2008, 16(1): 048-51. doi: 10.11993/j.issn.1673-1948.2008.01.013

[Abstract](2009) [PDF 458KB](666)

Abstract:
There is a growing need to make submarine maintenance plans and distribute repair missions based on the research of damage level assessment. Considering the index of torpedo weapon system and the characteristics of damage evaluation elements, a damage level assessment model based on evidential reasoning(ER) algorithm for multiple attribute decision analysis was presented. The model can combine multiple basic assessments of damage elements, deal with quantitative or qualitative information with uncertainty and subjectivity, and calculate the confidence degree of uncertainty. Therefore, it is an effective tool for the evaluation of submarine battlefield damage level. The evaluation results show that the model can deal with the information with uncertainty during the course of level assessment, and benifit repair decision-making.

Study on Shooting Forbidden Zone of Homing Torpedo

CUI Shao-bo, JIA Yue, ZHAO Xue-tao, LIN Xian-jie

2008, 16(1): 052-55. doi: 10.11993/j.issn.1673-1948.2008.01.014

[Abstract](1689) [PDF 451KB](628)

Abstract:
In order to develop the power of torpedo weapon and guarantee the safety of our troops, shooting forbidden zone of homing torpedo was studied. The definition and influence factors of shooting forbidden zone of torpedo weapon were introduced, and the principle of dividing forbidden zone was analyzed. Taking MK 46 torpedo for example, the shooting forbidden zones of the shipborne-launched, airdrop-launched and rocket-assisted-launched torpedoes were analyzed and calculated. The shooting forbidden zone plots under three launch modes were given in order to offer a reference for the operational application of homing torpedo, such as to determine whether our troop falls into the zone or not and how withdraws from the zone.

Application of Software Engineering Method to 3D Modeling of Weapon

ZHAO Wen-ting, KANG Feng-ju, WEI Jia-ning, SONG Qiang

2008, 16(1): 056-59. doi: 10.11993/j.issn.1673-1948.2008.01.015

[Abstract](1440) [PDF 524KB](749)

Abstract:
Aiming at the need for 3D modeling of sophisticated weapon, the development methods of software engineering such as waterfall model, transform model and increment model were analyzed and compared, and the increment model was introduced into 3D modeling for weapon. Firstly, the 3D model was divided into different increment units based on the information gained from requirement analysis; secondly, the increment units were designed in detail, and the development and test of the units based on Multigen Creator were completed; finally, the units were assembled and tested. Application result proves that the method can improve the repetitiousness and development efficiency of model, and satisfy the requirement for reality and real time in visual simulation system.

2008 Vol. 16, No. 1

Journal News> >

Download> >