Advanced Search

2002 Vol. 28, No. 4

  Previous Issue | Next Issue 
Display Method:
Optimal Terminal Missile Guidance Law Based on Fuzzy Neural Networks
DONG Chao-yang, JING Shao-guang, WANG Qing, ZHANG Ming
2002, 28(4): 373-375.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 715
Abstract:
Because fuzzy neural networks technique has the advantages not only strong adaptability to nonlinear systems but also quick learning ability, it has been applied to nonlinear systems successfully. an optimal terminal missile guidance law based on fuzzy neural networks for the advanced missiles with thruster vector control is presented. In the design of optimal guidance law, the minimum of missile energy loss and miss distance is required while the nonlinear character of the thruster vector control is considered. In addition, fuzzy learning rules are presented to improve the learning ability of the neural networks system. Numerical simulation results are given to illustrate that the presented fuzzy neural networks guidance law has good performance to hit maneuvering targets.
Numerical Investigation on Radiation of Enclosure Containing Non-Uniform Radiative Gas
ZHANG Xiao-ying, WANG Xian-wei, ZHU Gu-jun
2002, 28(4): 376-378.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 951
Abstract:
To calculate the infrared radiation characteristics of an enclosure containing inhomogeneous radiative gas, a method was developed by resolving the integral equations of radiative transfer. Attention was also focused on how to calculate the spatial distribution and the spectral distribution of radiation by computer. As an example, the radiation of one type of axial symmetrical nozzle was reported and compared with the result obtained from a traditional method for calculating radiant heat transfer.
Geometrical Problems Involved in Radiation-Calculation of Heteromorphosis Cavity
ZHANG Xiao-ying, ZHANG Jian-qiang
2002, 28(4): 379-382.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1050
Abstract:
To calculate numerically the radiation of a enclosure within a heteromorphosis cavity, attention was focused on: how to decide the visibility between two surfaces, how to improve the old method of configuration factor computation, how to approximately and efficiently decide the radiation resource of directional, spectral radiation in cavity. As an example, configuration factors in two type of nozzles were calculated and tested to verify the rationality and validity of the method.
Novel Fault Detection Approach and Its Application to Helicopter Actuators
DAI Ji-yang, MAO Jian-qin, XU Dong-sheng
2002, 28(4): 383-386.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 813
Abstract:
A new fault detection approach was presented, in which a key coefficient group consisting of partial wavelet coefficients was used to describe fault features, a fuzzy-tree was taken as the model of fault feature classification. As an example,the method was applied to the real-time fault detection of the actuators of UH-60A helicopter. Simulation results showed that the proposed fault detection technique possesses satisfactory detecting accuracy, good capability of overcoming noises, and the function of trailing changes in system parameters. Furthermore, the detecting precision can be markedly improved by increasing the number of wavelet coefficients in the key coefficient group.
Experimental Investigation on High-Loading Transonic Compressor Rotor
DENG Bao-yang, GUI Xing-min, YUAN Wei, NIE Chao-qun
2002, 28(4): 387-390.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 798
Abstract:
Unsteady pressure transducers with high frequency response were used to investigate tip clearance flows in a transonic compressor rotor (ATS-2), which is a high-loading compressor with 2.2 designed pressure ratio. Static pressure contours were obtained for different operating conditions at several different speeds. It was followed that, not only an attached oblique shock emanating from the leading edge and a secondary normal shock exist in the passage at 100% speed, but also a short-range normal shock appears near the suction surface. Withclosing the outlet throttle, the shock waves move forward and finally merge into normal shock near the leading edge, meanwhile, the stage performance reaches the peak efficiency. The overall performances of ATS-2 with two different tip clearance casings were compared. It reveals that the change of casing structure and tip clearance seriously influence the performance of the compressor.
Research of Air Traffic Control Simulation Environment
YANG Zhen-peng, YU Bao-feng, WANG Xing-ren
2002, 28(4): 391-394.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1001
Abstract:
A simulation method of air traffic control was studied, which is able to support training and some research project. The simulation content of air traffic control was introduced. The framework and model of simulation environment were established by analyzing its important factors. Based on techniques of distributed interactive simulation and virtual reality, scene database and 3-dimension scene generation, facilities simulation, computer generated plane, scenario generation and tasks administration were discussed. The result was introduced at the end.
Numerical Analysis of Complex Flowfields Around Multi-Wing Missiles and Its Aerodynamic Force Computations
HUANG Xian-lu, YAN Chao, CHEN Liang, LONG Yao-song
2002, 28(4): 395-398.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 914
Abstract:
The applications of modified Jameson's scheme to the complex flow around the missiles with canards and tails, result in good agreement between computations and experiment data of the standard missile model of U.S.A.. In computations, the latest modifications of Jameson's scheme are adopted to extend applications of the scheme to high supersonic and high Reynolds number flows. The multi-zone technique and 3-D elliptic grid generation method are also employed to precisely simulate the flows.
Effects of Heat Treatment Temperature on Properties of Hard Chromium Coating
ZHANG Qi, GUAN Shan, HU Ru-nan
2002, 28(4): 399-401.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1325
Abstract:
Microhardness and wear resistance of a hard chromium coating obtained with a solution containing organic additive were investigated as a function of heat treatment temperature. Meanwhile, XPS, EDAX and X-ray diffraction analyses were conducted to reveal the underlying micromechanism. It was found that: (1) the microhardness and the wear resistance both were significantly improved when the coating was heat-treated at 200℃~300℃ for 1 hour; (2) the content of carbon element within coating was rather high; (3) no changes in crystal structure could be detected for the heat-treated coating. Based on the above results,it was suggested that some sort of organic carbonides must be generated during the heat-treatment, which should be responsible for the properties and improvements.
Third-Order Constitutive Law for Nonlinear Elastic Materials
WANG Shou-mei, XU Ming, LI Ning
2002, 28(4): 402-404.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1294
Abstract:
A rigorous derivation of constitutive laws for nonlinear behavior of compressible and incompressible elasticity is presented. As a tensor-valued function with a single tensor variable, i.e. strain, stress is expressed as a tensor polynomial that contains high order elasticity tensors. Various symmetric features of these tensors are then introduced to simplify the expression. Finally, for isotropic material the constitutive laws and strain energy functions are obtained. The expressions satisfy the criterion known as representation theorem for tensor functions and are complete and irreducible.
Agent Coordination Mechanisms for Scheduling System Based MAS
ZENG Bo, YANG Jian-jun
2002, 28(4): 405-408.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 867
Abstract:
To overcome CNP's (Contract Net Protocol) defects in Shop-Floor Scheduling System based MAS, a new method was presented dealing with task distributing and scheduling based on GPGP (Generalized Partial Global Planning) coordination mechanisms, and TAEMS (Task Analysis, Environment Modeling and Simulation language). A task/capability environment model and the process of scheduling part were put forward that can provide the basic structure of knowledge-based scheduling. In MM-MES, a manufacturing execution system based MAS, they were implemented to research distributed manufacturing system's scheduling and coordination.
Design of Telemeter and Telecommand Base Station of Pilotless Helicopter with Object-Oriented Method
ZHAO Qi, ZHANG Xiao-lin
2002, 28(4): 409-412.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 978
Abstract:
Object-oriented　method is more and more widely used in the system design. The requirement and characteristics of the monitoring and processing system of a coaxal pilotless helicopter are analyzed .The system is an important component part in pilotless helicopter. In the course of executing task, the director can control the pilotless helicopter depending on the parameter of flying and equipment . Based on object oriented analyses, object oriented design and object oriented programming a detailed design scheme of the monitoring and processing system is discussed. With its high performance in reusability, improvability, testability, portability, maintainability, expandability, it has been tested to be able to meet the demands of flight.
Study of Atomizing Characteristics of Two-Phase Flow Emulsification Water Mist Nozzles
YANG Li-jun, WANG Wei, HU Ze-bao, ZHANG Zhen-peng
2002, 28(4): 413-416.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1254
Abstract:
For the objective of studying the structure of an atomizing nozzle which is the key component of a water mist fire-fighting equipment, this paper presents a detailed experimental investigation of the atomizing characteristics of a two-phase flow emulsification nozzle by the use of a Malvern particle size analyzer. In the experiment, the media is the mixture of water and air. The operating characteristics of the emulsification nozzle and the influences of the water pressure and air pressure on the atomizing characteristics of the nozzle have been analyzed. The experimental results show that the atomizing characteristics of this nozzle satisfy the requirements of the water mist fire-fighting system very well.
Coherent Structures in Turbulent Boundary Layer with Adverse Pressure Gradients
LU Li-peng, LI Zhao-rui
2002, 28(4): 417-419.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1040
Abstract:
By using the idea of resonant triad of the theory of hydrodynamic stability, the coherent structures in a turbulent boundary layer were investigated as a function of steady-adverse-pressure-gradient(SAPG) and changing-adverse-pressure-gradient(CAPG) flow cases. It was found that the adverse pressure gradient enhanced the growth rate of the resonant triads, enlarged the parameter range for the growing cases, and reduced the streamwise dimension, while the spanwise spacing of the streaky structures in all four cases remained approximately the same. And the greater the adverse pressure gradient, the stronger the above effects. For CAPG flows, the case with reducing pressure gradient produced the strongest effect on the coherent structures, though the same pressure gradient was remained in the end of evolution.
Simulated Design of Multifunctional Cockpit Display with Preview and Predictor Function
YUAN Hao, YU Li-ming, WANG Zhan-lin
2002, 28(4): 420-423.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 896
Abstract:
The preview and predictive information is introduced to cockpit display to make the future state of flight perceptible, so as to exert advanced control to vehicles. The multifunctional cockpit display with preview and predictor function is preliminarily designed by analyzing the landing process of an aircraft. An intelligent error signal display concept was proposed by applying optimal preview theory to flight height error display. The simulated design of 3D and 4D display were introduced. Finally, simulation experiments were given to compare the multifunctional display with the ordinary display.
Wall Pressure Distribution Induced by Saw-Tooth Flap
ZHANG Pan-feng, WANG Jin-jun, LI Ya-chen
2002, 28(4): 424-427.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 865
Abstract:
Wall pressure distribution induced by the saw-tooth flap has been investigated with electronic pressure scanner in wind tunnel. The results showed that the shear layer of the saw-tooth flap separated at x/h=(6 upstream and reattached at x/h≈20 downstream, which is the same with the plate flap; The transverse location of the flap has little influence on the mean pressure distribution, and the distribution of pressure fluctuation along the saw-tooth groove is greater than that along the saw-tooth tip; The saw-tooth can block the flow and much more effectively reduce the pressure fluctuation downstream.
Research on Geometrical Features of Assembly of Aerocraft and Container
MENG Cai, WANG Tian-miao, WANG Jia-shun, WANG Qing-zhu
2002, 28(4): 428-431.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 841
Abstract:
Based on the advanced adapter-based container launching technology, the geometrical features of the assembly of aerocraft & container are studied. Taking advantage of the planar assembly model, the tolerances to fit clearances are analyzed, which have effects on size, shape, location of areocraft and etc. Furthermore, the parameter design of three-dimensional model is tried. Meanwhile,the effects that interferences have on fit clearances and steering ability is analyzed by emulator. The results indicates that it can provide essential theory references for design, assembly and coordination.
Background Function for Generation of Unstructured Grids
ZENG Lan-ying, WU Song-ping
2002, 28(4): 432-434.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 985
Abstract:
Background information is one of the important aspects in the generation of unstructured grids by advancing-front method. Background information is generally obtained through creating background grids. To avoid the waste of time and memories in creating background grids, the article proposes an adaptive function to control the size of grids. It was proved that the method was useful and high effective. Based on the unstructured grids generated with the above function, and in combination with finite volume method, hypersonic nonequilibrium flows with chemical reactions were successfully calculated.
Integrated Aerodynamic/Structural Design Optimization for Wing of Trunkliner
DONG Bo, ZHANG Xiao-dong, LI Zheng-neng
2002, 28(4): 435-437.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 841
Abstract:
An integrated aerodynamic/structural design method for a wing of trunkliner is studied to obtain a tool for tradeoff between the contradictory demands of aerodynamic and structural design. Non-isentropic potential equation CFD method and beam theory model are introduced into the analysis of the design. A sequence of approximations constructed using GSE are optimized by SQP method to approach the optimum solution. The wing of a trunkliner is optimized as an example to demonstrate the feasibility of the method.
Bucking Delaminating of Composite Sandwich Plates under Hygrothermal Conditions
JIANG Li, ZHANG Zhi-min
2002, 28(4): 438-442.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 842
Abstract:
To analyze the buckling of elliptical face-core delaminating in composite sandwich plates, a two-dimensional elastic foundation model was established. A displacement function was considered to describe the buckling shapes. By taking the effects of hygrothermal conditions, of the core and of the composite adjacent to delaminating location into account, Reyleigh-Ritz energy method was used to predict the critical buckling load, as a function of composite material, laying angle and hygrothermal condition.
Method of Using Neural Network Combined with D-S Theory to Carry Out HRR Target Recognition
WANG Mao-lu, LI Shao-hong, MAO Shi-yi
2002, 28(4): 443-446.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 805
Abstract:
Based on the Shafer-Dempster reasoning theory, the method of coherent and non-coherent data fusion is studied. The algorithms of multi-sensor data fusion, which include center fusion and distributed fusion. It has been improved that the result of distributed recursive algorithms is better than others. A method of using LINN neural network combined with data fusion is developed to carry out the target recognition. Using high resolution range image of four kinds of target, the result of recognition is put into multi sensor, and is fused then. The correct recognition result is improved greatly by this method compared with using neural network only.
Numerical Simulation of Multipath Effect of Active Radar Seeker
DUAN Shi-zhong, ZHOU Yin-qing, ZHANG Meng, WANG Zu-li
2002, 28(4): 447-450.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1037
Abstract:
A time domain model for complex envelope simulation of multipath effect is presented based on multi-reflect-point target model. The model was used to calculate return waves of flat and fluctuant surfaces of land or sea. The 3D surface model of land and sea was built by the random fractal interpolation method with measured data. Signals from various roughness surfaces were computed. Simulation of low altitude target track under multipath effect environment was conducted with the active seeker model. The results indicated that multipath effect can bring large error for low altitude target tracking.
Automatic Selection for Standard Joint Locator in Aircraft Assembly Fixtures
ZHENG Guo-lei, ZHU Xin-xiong, XU De, ZENG Chun-ling
2002, 28(4): 451-454.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 779
Abstract:
Single structural parts are widely used in the structure of　modern aircraft, and this leads to mostly adopt components in aircraft assembly fixtures to locate product joints and process holes. Each of these components usually consists of a working part and a standard joint locator. In order to decrease the time, fixtures begin to be designed with CAD techniques, including the development and application of fixture-specialized design system. So automating the design of locators is very important to further increase the fixture design efficiency. Selecting and creating a standard joint locator is most costly during the design of a locator with a CAD system. Some new concepts, such as possible locating area, are defined firstly. Based on these concepts, an algorithm to autonomously select and create a standard joint locator is proposed. This algorithm has already been applied to develop the module "automatic design of joint locators" in the FixCAD system.
Data Management in Conceptual Aircraft Design Process
WANG Gang-lin, WU Zhe
2002, 28(4): 455-458.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1094
Abstract:
Data used in conceptual aircraft design process is extraordinary excessive. It is composed of many kinds of data, such as digital, diagram and document, etc. Especially, the data has the strong requirement of security. This paper was focused on how to use the advanced database technology to manage all the data design process with efficiency and rationality. By analyzing the characteristics of the data in conceptual aircraft design process, the data were divided into several species. A new technique for data management in conceptual aircraft design was brought forward, which is use the advanced and new object-oriented technology that was developed in recent generation to classify and manage the data in conceptual aircraft design process, and a simple instance is also presented. Finally, it introduced some attentions should be paid in database design and use process.
Experimental Investigation on Characteristics of Heat Transfer and Pressure Drop of Unusual Spirally Fluted Tube
CUI Hai-ting, YUAN Xiu-gan, YAO Zhong-peng
2002, 28(4): 459-461.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1006
Abstract:
Experiments were conducted on a new heat transfer enhanced tube-unusual spirally fluted tube developed based on spirally corrugated ones. Heat transfer and pressure drop characteristics of the tube with turbulent flow were examined as a function of tube geometry and water flow rate. Statistical correlations for friction factor and heat transfer coefficient were developed from a large amount of data by a multivariable linear regression analysis. Factor effecting heat transfer and flow were analysised. The results shown that heat transfer coefficient can be enhanced by 3.0%~8% while the friction force can be reduced by 5%~10%,compared with that of ordinary spirally fluted tube.
General Design and Control Law of BackLaunched AirtoAir Missile
WANG Yi-ning, JIANG Yu-xian
2002, 28(4): 462-464.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 774
Abstract:
The realization to launch air-to-air missile backward is studied.The necessity and possibility on technology are clarified.Then the issues encluded in engineering practice are analysed,such as the still stability of missile's attitude motion. A synthetic scheme to solve the essues is presented. Based on the scheme, system model is developed. The design and simulation of this system are done. The result shows it is possible to launch air-to-air missile backward.
Theoretical Study on Vibration Active Control of Power Supply and Pipeline Systems
JIAO Zong-xia, CHEN Ping, HUA Qing, WANG Shao-ping
2002, 28(4): 465-469.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1439
Abstract:
The vibrations problem of fluid power supply and piping systems in aircraft is discussed,and presented a vibration active control method to reduce the vibrations of fluid power supply and piping systems. The multi-layer PZT is taken as the driver which is of characteristics of large force output, high frequency bandwith and small volume. The auto optimum control method is adopted, which can adjust control parameters at any time to aganist the disturbance.The simulation and experiment result prove that the scheme is efficient. All of the work is benefit to the vibration control in hydraulic system.
Application of Robust Optimal Control to Servo Systems
YAN Xi-jun, GAO Jin-yuan
2002, 28(4): 470-472.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 1087
Abstract:
Considering the characteristics of servo system, a robust-optimal control method to deal with object's uncertainty and disturbance was proposed. The method was based on an improved control structure, and integrated the excellences of robust control method and optimal control method. The achievement process was given by an example. Simulation results indicated that the method can effectively restrain disturbance, and reduce the sensitivity of the system. In addition, it was found that the system robustness and tracking performance is preferable.
Experimental Research on Laser Bending Mechanism
WANG Xiu
2002, 28(4): 473-476.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 881
Abstract:
The deformation of laser bending is identified to be a result of the thermal strain and phase transformation strain through real-time measuring the dynamic micro-deformation of the specimen and microstructure analysis in the cross section of heated region center under the condition of laser-material non-melting interaction. Laser bending mechanism is described as Temperature Gradient Mechanism. When the temperature gradient is enough small, the thinner specimen produces the buckling due to lost steady state and the thicker specimen produces the upsetting due to compressed in the heated zone. Experimental results show that the deformation extent and direction of the specimen depend on the energy absorbed by the specimen, the composition peculiarity of the specimen and the specimen thickness, and give that influence factors vary with the laser bending deformation. The conclusion reveals the mechanism of laser bending and lays a foundation of research on the process of laser bending further.
Fault Diagnosis for Navigational Sensors Based on Modulated Gaussian Wavelet Transformation
WENG Hai-na, FANG Jian-cheng, YANG Gong-liu, ZHANG Zhen-peng
2002, 28(4): 477-480.
Abstract References Relative Articles Resource File Access Statistics iconViews $!{v.htmlCount} iconDownload 769
Abstract:
In order to improve the online fault-detecting capability of multi-sensor integrated navigation system, a MGWT-based fault diagnosis algorithm for navigation sensors was presented based on analysis of characteristics of modulated Gaussian wavelet (MGW). With this method, the effectiveness of each sensor can be directly detected by using the observing variables of the sensors. Some soft faults (such as the anomaly of covariance) can be detected online. Simulation result proved the effectiveness of this method.

Copyright © Journal of Beijing University of Aeronautics and Astronautics

Address: Editorial Department of Journal of Beijing University of Aeronautics and Astronautics, 37 Xueyuan Road, Haidian District, Beijing Post Code: 100191 Email: jbuaa@buaa.edu.cn

Supported by: Beijing Renhe Information Technology Co., Ltd.