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2004 Vol. 30, No. 03

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Application of FEA and laser measurer for optimization design of FOG
Lin Heng, Du Xinzheng, Zhang Chunxi, Ma Jing
2004, 30(03): 189-191.
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The vibration stability of FOG(fiber-optic gyroscope) is one of the most important factors in design. With the theories of vibration analysis and finite element analysis (FEA), the natural frequency, vibration modes and dynamic analysis were calculated and simulated by ANSYS5.7. The FOG's vibration modes, within 0~5 kHz, were measured with Polytec-PS200 vibration meter. Compared with the FOG's output characteristic under the vibration, the relation had been found between components' vibration characteristic and the vibration stability of FOG. An optimization structure of FOG was provided based on the research results. It's null shift output was minished about 65%.
Simultaneous lateral thrust and aerodynamic control of an agile missile
Zou Hui, Chen Wanchun, Wang Peng, Yin Xingliang
2004, 30(03): 192-196.
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The blended control of a tail-controlled agile missile with attitude control motors is discussed. A controller, including aerodynamic control surface and pulse type lateral jets, was developed. It was divided into two parts: the control law and the blend logic. The control law can be designed easily as before, and the blend logic commands the two actuators. Simulations had been carried out to show the performance. Effect of the distance between motors and the center of gravity of the interceptor had been also discussed.
Analysis of climbing obstacle capability of lunar rover with planetary wheel
Deng Zongquan, Gao Haibo, Wang Shaochun, Hu Ming
2004, 30(03): 197-201.
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For determination of perpendicular climbing obstacle capability of lunar rover with planetary wheel, based on simplified mechanics model of rover the paper gives the relations between rover parameters and perpendicular climbing obstacle height under three conditions: simultaneously climbing obstacle by two front wheels, simultaneously climbing obstacle by two rear wheels and climbing obstacle by single wheel. Then maximum perpendicular climbing obstacle height of this rover is calculated. Simulation analysis to above three conditions by ADAMS is done. The simulation analysis gives conclusion that theory inference result is reliable.
Tensile mechanical properties and constitutive relation of microcellular polycarbonate
Lu Zixing, Zhang Hui
2004, 30(03): 202-205.
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Microcellular plastics is a kind of special foamed plastic with some unique mechanical properties. On the basis of tensile test data of microcellular polycarbonate, some mechanical properties are investigated in this paper, including the effects of density and strain rate on the tensile stress-strain curves. Finally, the numerical fits to tensile constitutive relation of microcellular polycarbonate are performed by means of Boltzmann's principle and relaxation modulus. A good agreement between theoretical prediction and experimental data is obtained.
Structural design study of a micro-turbojet engine
Huang Zhiguo, Shan Peng, Wang Yanrong
2004, 30(03): 206-209.
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The presented work is referred to the structural design of a high power density micro-turbojet engine with a thrust 100 N and a rotational speed 105 r/min. First, the general overall tectonic characteristics of a microengine are mentioned. Secondly, the particular structural design characteristics of this micro-turbojet engine are analyzed. Finally, the intensity validation of two rotating components is introduced. The analytic results show that the structural designs of rotating components satisfied the demands of structural integrity. The experiences in the design processes are valuable for the developing of a high thrust/weight ratio micro-turbojet engine.
Research on the reliability modeling of SCI rings in avionics system
Jiang Zhen, Shao Dingrong, Xiong Huagang
2004, 30(03): 210-213.
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The problem of reliability modeling of the SCI(scalable coherent interface) is studied. According to the specification of SCI protocol and the ICD(interface control document) file as well as the reference in the design of avionics system, a message-based source-destination reliability criteria is proposed and the reliability models of the three SCI rings are developed. Conclusions show that the proposed reliability criteria is appropriate to the design of the avionics system where degraded running is a must.
Using grey theory estimates cost of unmanned plane's repairing
Chen Yuhong, Liu Jun
2004, 30(03): 214-216.
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The estimate about the cost of repairing is important to the LCC(life cycle cost) estimate of unmanned air vehicle, which is time sequence function. The traditional method can not estimate the LCC accurately because the quantity of the samples is limited. The grey theory is introduced to estimate the cost of repairing about unmanned air vehicle by using the model GM(1,1) . The result of the estimation is quite accurate. This method is very effective to estimate the cost of repairing some unmanned air vehicle.
Artificial-neural-network-based nonlinear adaptive control and simulation
Wei Dong, Ma Ruiping, Zhang Minglian, Shi Xiaorong
2004, 30(03): 217-221.
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The increasing complexity of the nonlinear systems highlights the need for advanced modeling and control techniques for effective control. An artificial-neural-network-based nonlinear adaptive control system was studied, which identified the dynamics of the plant with improved NARMA(nonlinear auto-regressive moving average) model at first. Then, the control algorithm was deduced with respect to the model directly. An adaptive system was designed to control a longitudinal missile autopilot which achieves tracking of external reference commands in angle of attack.Simulation results illustrate the ability of this technique to compensate for unmodeled dynamics and uncertain plant nonlinearities.
Delay analysis of self-organized TDMA VHF datalink
Zhang Jun, Li Zhongxiao
2004, 30(03): 222-226.
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The method of slots reservation affect on the time delay performance of self-organized time division multiple access (S-TDMA) system heavily. In allusion to the backdate search arithmetic typically used in the dynamic slot assignment scheme, the influence exerted on message delay by slot idle probability and reservation collision probability is analyzed in this paper. A detailed analysis of the relationship between the message delay and the number of users is also presented, as well as the relationship between the message delay and the speed of data. In the end, an alternative arithmetic namely sequential search arithmetic is proposed. The simulation results indicate that the delay performance of this arithmetic is superior to backdate search arithmetic.
Prediction of aircraft handling qualities and pilot induced oscillation susceptibility using unified theory
Xiong Lingfang, Fang Zhenping
2004, 30(03): 227-231.
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A unified theory is offered that can provide predictions of handling qualities levels and PIO(pilot induced oscillation) rating levels in single-axis tracking tasks, with linear or nonlinear vehicle dynamics. The theory is derived from the feedback topology of the structural model and a set of rules for selecting this mode's parameters. It is then applied to a hypothetical aircraft with and without rate limiter to analyze handling qualities and PIO. These results match well with other criteria. In addition, some parts of model are also discussed to provide for selecting parameters.
Design and implementation of a communication server for monitoring large-scale fleets
Yuan Cangzhou, Liu Zhongkan, Zhang Qishan
2004, 30(03): 232-235.
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To support large-scale fleets to communicate with multiple monitoring centers using both short message service and general packet radio service, a communication server was designed based on the careful study of the communication model. The server implemented most critical communication functions such as packet switching, packet broadcasting, protocols transferring, and etc. The thought of sacrificing memory for speed was sufficiently deployed in data structure design, and multithread, message and component technologies were used in realization to improve the efficiency of the server. The test results show that the server works effective and steady in large -scale fleets monitoring systems.
Research and implementation on Web services-based single sign-on system
Hu Yishi, Huai Jinpeng
2004, 30(03): 236-239.
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Users need to authenticate themselves to each service provider during they finish an operation that involves several services owned by different providers in the dynamic loose-couple environment because of development of distributed technology and application. Analyses the Web services-based single sign-on mechanism in a distributed environment and implements the single sign-on system in the Web services-based supporting application environment.
New location algorithm of car license plate using cross-correlation vector map
Cao Xiaoguang, Zhu Fengyun
2004, 30(03): 240-243.
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Vector map is a kind of computer graphics formed by matrix of vectors. These vectors are results of cross-correlation of two related particle images.This technique is called PIV(particle image velocimetry). A new algorithm for extraction of car license plate is introduced, which is called VMLA(vector map location algorithm). The idea of VMLA is inspired by the method to get the cross-correlation vector map of PIV. It based on thefact that the two edges of strokes of license plate characters and numbers cause a special local structural pattern in the cross-correlation vector map. Using this idea, the correct position of a plate could be extracted from vector maps of license plate images with complicated backgrounds. VMLA is adaptive to various license plate sizes and it also runs in real-time. Testing results on 540 license plate images show that the method is valid and efficient.
Development of intelligent magnetic heading sensor and analysis of its error compensation algorithms
Yang Xinyong, Huang Shengguo
2004, 30(03): 244-248.
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The design of a micro intelligent magnetic heading sensor and error sources which affect heading accuracy are introduced. Further, three compensation algorithms based on BP neural networks, least square method and ellipse-specific fitting method are presented respectively. Each compensation algorithm is analyzed in detail. From the point of specific algorithm implementation, accuracy, velocity, efficiency of each compensation algorithm are analyzed and testified based on experimental results.
Research on the application of Petri net to MTA
Ma Lin, Lü Chuan
2004, 30(03): 249-253.
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Problems of MTA were analyzed. Based on the discussion of the merits of Petri net, the concept of modeling the maintenance task with hierarchical-timed-colored Petri net was presented. The approach to describe the logical and temporal relation by Petri net was studied, and the procedure of setting up the model of maintenance task was also presented. Finally, a case study of determining the support resources with Petri net was conducted.
Technique based on surface element of prepositive disposal in predicting RCS of aircraft
Li Xiuyi, Ning Tao, Xi Ping
2004, 30(03): 254-257.
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Predicting RCS(radar cross section) of aircraft is the basic and important content of technology. A technique for prepositive disposal in predicting RCS of aircraft by using computer graphic method and NURBS(non-uniform rational B-spline) surface and Bézier surface is presented. The technique can realize the shadowing calculation, regroup of geometrical model and the transfer from NURBS surface to Bézier surface. The result proved that the technique possess the character of good shadow effect and high precision which is differ from former predicting technique which is based on face element.
Computation and research of the "zero-zero" jettison trajectories of the aircraft canopy
Gong Jie, Yang Chunxin, Yang Xinming, Xu Xiaodong
2004, 30(03): 258-262.
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The motion model of "zero-zero" jettison of aircraft canopy was developed to get the trajectories of the jettisoned canopy and the perfect jettison angle, and the agreement between model prediction and experimental measurement result was satisfactory. The rule of the air input of the underside cavity was also discussed in order to get the pressure curve .The result of all the research can be used to predict the trajectories of aircraft canopy in the "zero-zero" jettison.
Research and implementation on Web services-based service-oriented software architecture
Liu Bochao, Ma Xiaoxuan, Ge Sheng, Huai Jinpeng
2004, 30(03): 263-266.
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Based on the Web service-based service-oriented software architecture, ACT-WSOA(ACT-Web service-based service oriented architecture) is proposed and implemented, which includes service requestor based on the general client, service registry based on the UDDI(universal description, discovery and integration) server and service provider based on the Web service runtime. It follows and supports the international open specifications, such as UDDI, WSDL(Web services description language), SOAP(simple object access protocol), and provides base services and infrastructure for Web service.
Optimizing design method for centrifugal impeller its engineering application and numerical simulation
Dai Simin
2004, 30(03): 267-271.
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An optimizing design method for centrifugal compressor impeller has been presented, which has been applied to an engineering design of a practical centrifugal compressor. 3D viscous numerical simulation has been performed to these three stage compressors with CFD software TASCflow. Therefore the optimizing design method has been evaluated objectively by experiment data and numerical simulation results.
Residual stress analysis of thermal barrier coatings
Li Zhihua, Li Huanxi, Xu Huibin, Gong Shengkai
2004, 30(03): 272-275.
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An expression for calculating residual stresses in a thermal barrier coating structure was developed. Effects of Young's modulus, coefficients of thermal expansion (CTE) and thicknesses of the ceramic coating and thermally grown oxide (TGO) were analyzed based on the expression. The main results are as follows: compressive in-plane residual stresses are generated with lowering temperature in both ceramic coating and TGO, which exhibits a linear relationship with the temperature drop. And the greater the Young's modulus or the less the CTE, the greater the residual stress in ceramic coating or in TGO. While the influence of thickness on residual stress is negligible. The maximum residual stress in ceramic coating is about 300 MPa, much less than the compressive strength of bulk ceramic material. On the above results, it is suggested that buckling of delaminated ceramic coating should be responsible for its final spallation.
Study of algorithm for maneuvering target state estimator
Peng Kemao, Shen Gongzhang, Wen Chuanyuan
2004, 30(03): 276-279.
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The algorithm of state estimator for maneuvering target is studied based on the assumption of quasi-steady state of flight path of the fighter. By selecting virtual measure variable and state variable, and by supposing the flight path of target is in quasi-steady state, this algorithm converts the problem ofnonlinear filtering and estimation with nine variables into one three-ordered and three two-ordered linear filtering and estimation problems. It is showed that the algorithm has light computing load and good filter precision, and is capacity to meet the requirements of integrated control in the simulation result of integrated control system.
Temperature characteristic of a kind of hollow-fibber membrane module used for oxygen enrichment
Liu Meng, Wang Jun
2004, 30(03): 280-282.
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The influence of temperature on O2/N2 separating property of a kind of hollow-fibber membrane module is studied through experiments. The result shows the working temperature can highly affect the separation characteristic of the membrane and does not affect oxygen concentration, which can be used for increasing rich oxygen production by controlling the working temperature of the membrane.

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