Table of Content

31 August 2009, Volume 30 Issue 8

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Paper

Simulation of Pressure Field near Canister Outlet for Underwater- launched Emulated Missile

WANG Han-ping, YU Wen-hui, WEI Jian-feng

2009, 30(8):  1009-1013.  doi:10.3969/j.issn.1000-1093.2009.08.001

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The fluid field near canister outlet for underwater-launched emulating missile was simulated by using a 3D symmetric model based on dynamic meshing technology and VOF with phase transfer. The characteristics of Dubble pulsation near canister outlet, pressure-time curves and moment-time curve over the cover were achieved through several simulation cases; also effects of water compress?ibility and the initial temperature of work gas on load characteristics over cover system were analyzed and compared. The simulation results agreed with the test data very well in several key bubble pulsa?tion characteristics. The simulations also show that the initial temperature of work gas has great effect on the load pulsation duration over the cover and water compressibility is an un-negligible factor for simulation creditability. It provides a new kind of reference standard for load analysis of the cover sys?tem and the cover system design.

Research on the Influence of Annular Initiation on Penetrator Formation of Shaped Charge Conical Liners

WANG De-gong, LI Wen-bin, WANG Xiao-ming,ZHENG Yu, HAN Yu

2009, 30(8):  1014-1018.  doi:10.3969/j.issn.1000-1093.2009.08.002

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By using Lb-DYNA finite element hydrocode, the effects of liner’s cone angel, wall thick?ness and wall thickness variation on the penetrator formation of shaped charge conical liners were inves?tigated under direct and inverse direction annular initiations. The simulated results indicate that jet with nigh-top velocity can be gained under both direct and inverse annular initiation when the cone an-gel is less than 120° and JPC can be gotten under direct annular initiation when the cone angel is larger than 135°. The proving test was carried out, and the test results agree well with those of numerical simulations.

Experimental Investigation on Hugoniot Characteristic of Simulated Explosive in Warhead of ProtectedOverload Against Penetration

ZHAO Sheng-wei, CHU Zhe, LI Ming

2009, 30(8):  1019-1023.  doi:10.3969/j.issn.1000-1093.2009.08.003

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Data of shockwave and particle velocities in the explosive of simulating TNT were obtained by the flyer plate impact experiments at the impact pressure of below 1.2 GPa. Fitted curve of tested data is consistent with Hugoniot c-u curve of real cast TNl in the range of allowable error. So Hugo- niot characteristics of the explosive of simulating I NT are similar to that of real cast TNT. In experi?mental investigation on Hugoniot characteristic of explosive, the simulated explosive may substitute for the explosive in warhead to investigate dynamics of various materials.

Molecular Simulation Research on the Selecting of Bonding Agents for HTPB Propellant Based on Penetrability

JIAO Dong-ming, YANG Yue-cheng, QIANG Hong-fu, WU Wen-ming

2009, 30(8):  1024-1029.  doi:10.3969/j.issn.1000-1093.2009.08.004

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Based on restraining the diffusion of gas, membranes constructed by bonding agents, cling?ing to the surface of oxidant (AP), can improve tne chemical aging resistance of HTPB solid propel-lant. Through comparing the diffusion velocity of gas molecules, the effect of bonding agents on the action of chemical aging resistance of HTPB propellant was described, i.e. this method provides the theoretical foundation of selecting bonding agents for HTPB propellant. The diffusion coefficients of O2 in polyethylene and polystyrene were calculated by the molecular dynamics (MD) based on the amorphous models of polyethylene and polystyrene. Ihe simulated values are in agreement with exper?imented values, which validates the feasibility of simulating diffusion coefficient by MD method. The diffusion coefficients of O2 and H2O at 303 K in MAPO, HX-752, TAZ, TEA and MAPO? HAC were acquired through the constructed membranes of bonding agents. The simulated results show that, ac?cording to the ability of restraining the diffusion of gas, MAPO ? HAC is the best, MAPO is in the next step, HX-752 and TEA is bad, TAZ is the worst, which is consistent with the experimented result;the new developed bonding agents of PMS and PAMAM have the improved performance of chemical aging-resistance of HTPB propellant, which is similar with MAPO.

The Application of Thermal Flux Measurement to Design of B/KNO3 Igniting Charges

ZHOU Kui-jun, CHEN Hong-jun, YE Shu-qin,YANG Zheng-cai, Lü Jiang

2009, 30(8):  1030-1034.  doi:10.3969/j.issn.1000-1093.2009.08.005

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Design optimization of an igniter in a solid propellant rocket motor usually depends on its match test to the motor. As the matching tests have long time cycles and large costs, with the aid of thermal flux measurement, we can reduce the number of the matching tests, lower the test costs and shorten the design period. According to the principle of thermal flux measurement, a foil-shaped Pt thermal flux measurement meter and two thermal flux testing devices for electric igniter of solid pro?pellant rocket motor were designed ana manufactured. The transiently axial thermal flux distributions of three different shapes of B/KNO3 igniter charges were tested and analyzed. On the basis of the anal?yses, the shape of the B/KNO3 igniter charge in electric igniter ot ignitor motor of a certain air-to-air missile was determined and proved to be reasonable by the matching test between the motor and the ig?niter .

Quantitative Analysis of Components in OC-CS Spray by High Performance Liquid Chromatographic withDouble Wavelength UV Detection

SUN Li-quan, CHEN Zhen-he, QIU Ri-xiang,WANG Li-Jing, QIAN Wei, GENGLi-na, LUO Ai-qin

2009, 30(8):  1035-1038.  doi:10.3969/j.issn.1000-1093.2009.08.006

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The method of reversed-phase high performance liquid chromatography was established for determination of effective components in OC-CS spray using double wavelength UV detection under following conditions： a column of Kromasil Cl8 (250 mm><4.6 mm, 5 μm), mobile phase composed of methanol/water (80/20) at a flow rate of 0.8 mL/min, column temperature of 25℃ ; and the UV detection at 227 nm and 300 nm. Three key components in OC-CS spray were distinguished clearly,i. e. o-chlorobenzalmalononitrile (CS), oleoresin capsicum (OC) and dihydrocapsaicin (DC). This method is fast and simple, with satisfactory linear relationship between UV absorption and concentra?tion. It is instructive for modifying the standard method for detection of related components in the spray.

Study of Sonar Imagery Segmentation Algorithm Based on Improved Markov Random Field Model

YE Xiu-fen, WANG Xing-mei, FANG Chao,ZHANG Zhe-hui

2009, 30(8):  1039-1045.  doi:10.3969/j.issn.1000-1093.2009.08.007

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For sonar imagery has the disadvantages of low contrast ratio, poor quality, serious noise pollution and so on, compared with common optical image, it is difficult to get segmentation results with high precision and strong robustness, by using traditional segmentation algorithm. A sonar im?agery segmentation algorithm based on improved Markov random field (MRF) model was proposed. New three-class segmentation model parameters of the spatial neighborhood MRF were established. These model parameters and model parameters of the level interaction were applied to three-class seg?mentation in hierarchical MRF to get final precise three-class segmentation results. Lastly, segmenta?tion experiments of the man-made sonar imagery and real sonar imagery verify the algorithm proposed has high accuracy and adaptability. Because the spatial correlation between pixels is fully considered by the algorithm, the final segmentation performances are greatly improved.

A Classification Algorithm for Ground Mobile Targets Based on Magnetic Sensors

CUI Xun-xue, LIU Qi, ZHAO Wen-bo,QIU Guo-xin, XING Li-jun

2009, 30(8):  1046-1050.  doi:10.3969/j.issn.1000-1093.2009.08.008

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A novel classification algorithm was proposed for ground mobile targets based on magnetore?sistive signals, as most of weapons have a character made from much steel or iron. According to the principle of different earth magnetic influence produced by diverse vehicles, a mobile target can be de?tected and classified with a simple computation method by a magnetic sensor. The detection sensor is used for collecting a disturbed signal of earth magnetic field from a mobile target. .After some statistical samples are trained and a classification machine is designed, the target signal feature is tested for cate?gory pattern match. Three common targets were experimented. The experimented results are shown that the algorithm has a low computation cost and a better sorting accuracy, and can be applied to ground reconnaissance and target intrusion detection.

Effect of High Speed Spinning of Solid Fuel Ramjet on Steady Operation Range of Its Inlet

XIONG Zhi-ping, WU Xiao-song, SUN Bo,XIA Qiang

2009, 30(8):  1051-1055.  doi:10.3969/j.issn.1000-1093.2009.08.009

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For investigating influence of high speed spinning of the solid fuel ramjet on steady operation range of its inlet, the designed inlet was simulated numerically by computational fluuid dynamics at Mach number of 3, to obtain steady operation ranges at non-spinning, spin speeds of 10 kr/min and 30 kr/min, flowfield structures and overall performance of the inlet. The simulated results show that range of steady operation decreases with the increasing of spin speed, of which variation is smaller, in?fluences on flow characteristics and performance parameters are smaller; total pressure recovery coeffi?cient of tne inlet and Mach number of the outlet at high speed spinning are a little higher than those at non-spinning, mass capture ratio of the inlet and total pressure distortion index of the outlet at high speed spinning are the same as those at non-spinning.

Simulation and Analysis on the Lateral Vibration Characteristic of Vertical Launching for Submarine- borne Missile

PEI Xuan, ZHANG Yu-wen, YUAN Xu-long, ZHANG Ji-hua

2009, 30(8):  1056-1060.  doi:10.3969/j.issn.1000-1093.2009.08.010

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The ejecting process of vertical launching for submarine-borne missile is a complex dynamic process, which directly determine characteristic of the trajectory. By analyses of the fluid dynamics characteristics of missile vertical submarine-launching, stree feature of the spring seal ring’s deforma?tion and coupling between missile and ring, a lateral dynamics model of missile vertical launching was developed. Process and characteristics of lateral vibration of the missile at exiting from the tube were simulated and analyzed emphatically, some methods of mhiDitmg the body’s lateral vibration were giv?en .The studied result shows that rigidity and length of the seal ring can affect the lateral vibration ob?servably, the studied results provide gives theoretical foundation and study tools for the control of tra?jectory, launch safety assessment and missile launching system design.

Flexibility Analysis on Box Nose Girder Made of Sandwich Composite Materials

XU Wen-ming, YUAN Duan-cai, JIANG Zhi-gang, HU Ping

2009, 30(8):  1061-1065.  doi:10.3969/j.issn.1000-1093.2009.08.011

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In order to analyze the flexibility of box nose girder made of sandwich composite materials, it was solved by the analytical and the numerical methods. FLexibility of the girder was calculated theo-retically by being equivalent to an isotropy box girder with equal stiffness and. span and using primary beam theory, under consideration of shear deformation. A finit element model of the girder was estab?lished, its numerical result was obtained by the model. The analytical solution is accorded with that of finite element method well, which shows that the methods of solving flexibility of the girder are cor?rect.

Simulation on Flow Control for Drag Reduction of Revolution Body Using Bionic Dimpled Surface

ZHANG Cheng-chun, REN Lu-quan, WANG Jing, ZHANG Yong-zhi

2009, 30(8):  1066-1072.  doi:10.3969/j.issn.1000-1093.2009.08.012

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Numerical simulations on drag reductions for the dimpled and the smooth revolution bodies were performed and compared with SST k-ω turbulence model, to explain the reasons of iriction and base drag reductions on the bionic dimpled surface and the control behaviors to boundary layer near wall of the revolution body. The simulated results show that the dimpled surface arranged on the rear?ward of the revolution body reduces the skin friction drag by 8.05 %, the base drag by 1.9 % and the total drag by 6. 24 % at Mach number 0.4; the dimpled surface reduces the skin friction drag through reducing the velocity gradient and turbulent intensity, and reduces the base drag through weakening the pumping action on the flow behind the revolution body caused by the external flow; the flow con?trol behavior on boundary layer produced by dimpled surface displays that the low speed rotating vor?texes in the dimples like vortex cushions, which segregate the external flow and the revolution body; and the low speed rotating vortexes forming in the bottom of dimples can produce negative skin friction against to the other area, which can be considered a accessional impetus.

Airfoil Design Optimization at Low Reynolds Number

ZUO Lin-xuan, WANG Jin-jun

2009, 30(8):  1073-1077.  doi:10.3969/j.issn.1000-1093.2009.08.013

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The airfoil perturbation functions designed by Hicks-Henne were developed, and the multi?objective function carried out with multi parameters for airfoil design optimization was discussed too. By employing genetic algorithm, the SA7035 was taken as the optimization case at low Reynolds num-ber. I he optimized results results show that, with small variety of pitching moment coefficient at an?gle of attack 2°- 8°，the effectiveness factor of the airfoil is improved, to achieve multi-objective opti?mization purpose; the maximum lift to drag ratio and the maximum effectiveness factor are both signif?icantly improvedi by 14.5% and ID.2% respectively, and the corresponding angle of attack of the maximum effectiveness factor is decreased slightly. This optimization method can be applied in airfoil design at low Reynolds number.

Numerical Investigation of Early Fireball of Strong Explosion for Different Altitudes

TIAN Zhou, QIAO Deng-jiang, GUO Yong-hui

2009, 30(8):  1078-1083.  doi:10.3969/j.issn.1000-1093.2009.08.014

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For the evaluation of damage effects of strong explosion, the formation and developmental processes of radiation front and case shock of early fireball of strong explosion for the different altitudes were calculated numerically by the equations of one- dimensional radiation hydrodynamics with spherical symmetry, the calculated results were analyzed using scaling theory. The results show that the ex?panding velocity of radiation front and case shock increases, the beginning and ending positions and sustaining area of transition of radiation front increase, the decreasing process of central temperature of fireball increases, and the decreasing velocity of radiation energy slows, with the increase of explosion altitude; the parameters in fireball front satisfy basically the similarity laws of explosion after the shock transition of the fireball fronts.

Shape-Based 3D Head Data Clustering

NIU Jian-wei, LI Zhi-zhong

2009, 30(8):  1084-1088.  doi:10.3969/j.issn.1000-1093.2009.08.015

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shape characteristics of human body surface are not well reflected in traditional sizing method. This lowers fitting satisfaction level of wearing items which require close fitting contact with human body surface, such as helmets. It is helpful to solving the above problem that the sizing system is established by three-dimensional (3D) anthropomentric data, which carry abundant information of human body surface shape. Taking 447 3D head samples as example, the method describing shape dif?ferent was proposed by block-distance-based vector; shape grouping of the samples was performed by the method and the k-means clustering algorithm; the grouped results were compared and analyzed with those of a Utiinese national military standard of 3D head-face dimensions of male soldiers based on head breadth-length index and head height-length index. The compared results show that tlie obvious differences exist between the two methods, the proposed method can provide a reference for modifying the standard.

A Fuzzy Adaptive Algorithm Based on Current Statistical Model for Maneuvering Target Tracking

WANG Xiang-hua, QIN Zheng, YANG Hui-jie, YANG Xin-yu

2009, 30(8):  1089-1093.  doi:10.3969/j.issn.1000-1093.2009.08.016

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A basic current statistical model and an adaptive kalman filter algorithm can not track feeb- Iish maneuvering target precisely, though it has good estimate accuracy while the target maneuvers rapidly. In order to solve this problem, a novel nonlinear fuzzy membership function was presented to adjust the upper and lower limits of target acceleration adaptively, the validity of the new algorithm for feeblish maneuvering target was proved in theory. The simulated results show that, the new algorithm has great advantage compared with the basic current statistical model and the adaptive algorithm.

Thermal Effect of the Eddy Current Sensor Probe for Measuring the Gaps Between Curved Surfaces

WANG Peng, SI Shu-jia, DING Tian-huai,FU Zhi-bin

2009, 30(8):  1094-1097.  doi:10.3969/j.issn.1000-1093.2009.08.017

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The planar eddy current coil is an important device to detect the gap between tow complex curved surface bodies. In order to ensure its safety, its thermal effect was researched using the finite element temperature field analysis. The relation curves between temperature and time or current were simulated and proved by a series of experiments. It is found that the coil，s node temperature rises with time to a balance condition and the balance temperature increases with current’s rising. The permissi?ble maximum current was given in different safe temperature conditions.The research result provides the academic basis for the eddy current sensor probe’s safe application.

The Numerical Simulation of the Precision Radial Forging Processing of the Gun Barrel

FAN Li-xia, LIU Li-li, LIU Qing-dong,DONG Xue-hua

2009, 30(8):  1098-1102.  doi:10.3969/j.issn.1000-1093.2009.08.018

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The precision radial forging is a good method to form the barrel because of its high produc?tion rate, and the better fatigue properties of the gun barrel than that by conventional manufacturing methods. In Europe and U.S. army, most of the barrels for small caliber weapons with rapid firing rates, including the rifling and chamber geometry, are manufactured by the precision radial forging. However, only a few types of the rifling are manufactured by this technology in Cnina, and it is also very short of the theoretical analysis of the radial-forging process for the gun barrel. In tnis paper, a FEA software DEFORM-zD based on the updated iagrange formulation with a large rigid-plastic mate?rial behavior was used to model and simulate the stresses and the radialT forging load during the radial forging of tlie rifle part in a gun barrel. The quantitative relations between process and die variables were investigated by changing the parameters, which are be a basis for optimizing the process condi?tions .

Optimal Replacement Policy for Series Repairable System of N Components Based on Availability

TAN Lin, PU Ting, GUO Bo

2009, 30(8):  1103-1107.  doi:10.3969/j.issn.1000-1093.2009.08.019

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A series repairable system is one of the classical reliability models and is usually used in prac?tice .An optimal replacement policy for series repairable system is studied assuming that the component after repair is not “as good as new by using the geometric process model. The expressions of the long- run expected benefit and the availability per unit time are deduced. Furthermore, the replacement poli?cy model is presented with minimizing the availability rate subject to an appropriate cost rate. Lastly, a numerical example is presented, the results compared with the actual ones approve that the new mod?el is reasonable.

Micro-plasma Sprayed Hollow Mullite Thermal Barrier Coatings

HOU Ping-jun, WANG Han-gong, WANG Liu-ying,HUA Shao-chun, WU Yong-fa

2009, 30(8):  1108-1113.  doi:10.3969/j.issn.1000-1093.2009.08.020

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The hollow mullite thermal barrier coatings were deposited by Micro-plasma Spraying tech?nique. The bond strength, thermal barrier capability and the anti-thermal shock ability of the coating were tested. The tested results show that the average bond strength of the coating is 5.63 MPa, the fracture begins in the top coating; The thermal barrier of the coatings goes up form 11.5 °C to 40°C under the surface temperature going up form 400°C to 900 °C conditions in which the steady-state test is employed; the anti-thermal shock times are 165，135，117，81，and 34 when the test temperature is between 400 °C and 800 °C with interval of 100 °C ; the initial spallation of the mullite coating occurs at the edge of the specimen, and its speed increases at the end of thermal shock life. The main iauure reason of the coatings is the thermal residual stress accumulated during the thermal shock test.

Spatial Resolution Enhancement for Micro Computerized Tomography Based on Projection Compensation

LI Bao-lei, YANG Min, FUJian

2009, 30(8):  1114-1118.  doi:10.3969/j.issn.1000-1093.2009.08.021

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For micro-computerized tomography(CT), the imaging spatial resolution can be improved by increasing the projection magnification. While, for a certain size workpiece, the projection data is easily truncated with the increase of magnification, which results in imperfection of data and artifact and attenuation coefficient shift in CT image. One method was put forward for compensating the trun?cated projection. According to the proposed method, the workpiece were scanned twice separately un?der low magnification and high magnification. The projection was not truncated under low magnifica?tion and the Cl image with low spatial resolution was reconstructed. Then the CT image was magni?fied digitally and reprojected and the estimated value of the truncated projection matching the high magnification projection was obtained. In the end, the estimated value of the truncated projection was combined with the high magnification projection and the filter backprojection algorithm was executed,.to get the micro-CT image with locally enhanced spatial resolution. The feasibility of the method was validated by the simulation result and the practical experiment result.

Researcn on the Preparation Technology of Nano Ta Powder Using Induction Plasma

SHANG Fu-jun, SHI Hong-gang, WANG You-qi,HUANG wei, TIAN Kai-wen, WU Hong

2009, 30(8):  1119-1123.  doi:10.3969/j.issn.1000-1093.2009.08.022

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In order to control the particle size and morphology of capacitor grade Ta powder using plas- ma technology，the preparation experiments were performed by cnanging two main processing parame?ters to investigate influences of plasma power and feedrate on particle size, particle size distribution and morphology of the powder. The experimented results show that mean particle size of the powder in-creases ana specific surface area decreases with the increase of feedrate at a certain plasma power; mean particle size decreases and specific surface area increases with the increase of plasma power at a certain feedrate.

The Multi-step Predicting Controllers for Deterministic Networked Control Systems

ZHU Qi-xin, LIU Hong-li, HU Shou-song

2009, 30(8):  1124-1128.  doi:10.3969/j.issn.1000-1093.2009.08.023

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As network-induced delay is a stochastic variable, networked control systems are stochastic systems. For this kind of stochastic system, one can design its stochastic controllers when network-in-duced delay has a known probability distribution function, otherwise one can only design its determin?istic controllers. On some assumptions, the method of placing a specific amount of buffer at source node and object node of the systems was used to transform stochastic time delay to deterministic time delay. The systems with stochastic delay were transformed to a deterministic one. Based on linear time~invariation controlled object, multi-step predicting controllers of the systems were designed, which makes the closed loop system stabilizable and satisfies the separation principle with the observer.The simulation based on the unstaole inverted pendulum was performed. The simulated results show that the proposed method is effective.

Research Notes

A Stability-based Grid Multipath Routing Algorithm in Ad Hoc Networks

WANG Jie-min, WU Zheng-yu，SONG Han-tao,DING Gang-yi

2009, 30(8):  1129-1133.  doi:10.3969/j.issn.1000-1093.2009.08.024

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Most of the routing protocols for current ad hoc networks relies on traditional unipath rout?ing. Each routing discovery flood is associated with much routing packet losing, higher routing delay and higher routing load. To overcome the shortcomings of unipath routing protocols, a new multipath routing algorithm called stability-based grid multipath routing (SGMR), was proposed. SGMR fully utilizes location information, effectively confines the flooding area of routing query packet, and uses prediction strategy and node-disjoint path algorithm to select multiple stable node-disjoint routes. The simulated results show that SGMR has higher packet delivery ratio, lower routing average delay and routing load compared with LAR and AODV ?

Fast Recovery of Interfered Scrambling Code Sequence

WU Wen-jun, HUANG Zhi-ping, TANG Gui-lin,LIU Chun-wu

2009, 30(8):  1134-1138.  doi:10.3969/j.issn.1000-1093.2009.08.025

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The fast recovery of interfered scramoling code sequence was inguired into. A method based on the Walsh-Hadamard transformation to solve the scrambler generator polynomial was proposed, which improved the exhausted method. The initial state of the sequence was recovered with the algo?rithm A of fast correlation attack. With a different way of parity-check construction, the algorithm A was improved ? The new algorithm is no longer restricted by the number of scrambler generator polyno?mial's tap, and its original advantage of low compute complexity and easy implement are retained.

A Distributed Control System for an Autonomous Underwater Vehicle

GAO Jian, YAN Wei-sheng, ZHANG Fu-bin, ZHANG Li-chuan, ZHAO Ning-ning

2009, 30(8):  1139-1142.  doi:10.3969/j.issn.1000-1093.2009.08.026

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A new distributed control system using CAN bus for an autonomous underwater vehicle (AUV) was developed. In the well defined Hierarchy architecture, this control system consists of the task layer by the multi-function teleoperator., the coordination layer by the management and logging center, and the control layer by the navigation control center and other executor control nodes. The re?altime control and non-realtime task management are separated and realized by the different control nodes, whicn is convenient to maintain and upgrade the system. In the real experiment, the distribut?ed control system worked well, and the AUV executed the preprogrammed mission completely and ex?actly, wmch proved the successfulness of this system design.

Chaos Genetic Hybrid Algorithm and Its Application to Shear Stress Verifying of Spring

WANG Zhong-min, DAI Yi, ZHAO Hui

2009, 30(8):  1143-1146.  doi:10.3969/j.issn.1000-1093.2009.08.027

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A new chaps genetic hybrid algorithm (CGHA) based on float encoding was proposed. For producing better initialized species population, the coarse-searching was performed by chaos optimiza?tion, and the power function carrier was adopted to improve the ergodicity and the sufficiency of the chaos optimization. The fine-searching was performed by the genetic algorithm (GA), to guarantee evolution of species population. A chaos degenerate mutation operator was designed, to avoid searching being trapped in local minimum and converge to a global minimum. This new hybrid algorithm is used to solve the problem of shear stress verifying of a cylinder helix spring, which belongs in a typical problem of mechanical optimization design.しompared with traditional penalty function method, ckaos- Powell hybrid algorithm and standard GA, CGHA shows better performance at the aspect of solution precision and convergence speed than those of these algorithms. Therefore, it is an effective way to solve the problem of mechanical optimization design.

Design of Variable-structure Controller for Supercavitating Vehicle

WEI Ying-jie, Lü Rui, ZHANG Jia-zhong,YU Kai-ping, CAO Wei

2009, 30(8):  1147-1152.  doi:10.3969/j.issn.1000-1093.2009.08.028

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With the loss of the buoyancy and the occurrence of the planing force being brought by su?percavitation, the supercavitating vehicles confront complicate motion characters, such as tail-slap, structural vibrations and nonlinearity. These problems bring great difficulties for stability control de?sign, Througn analyzing the hydrodynamic forces acting on supercavitating vehicles, a dive-pitch-plane dynamics model for supercavitating vehicle was presented. According to open-loop system response, and due to the instability of the system, a variable-structure controller based on improved exponent ap?proaching law was designed, and mathematical simulation was performed for supercavitating vehicles with the controller. The simulation result demonstrates that the closed-loop system responds rapidly and has good performance.