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2004 Vol. 30, No. 02

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Real-time flight path planning for combat mission
Xia Jie, Gao Jinyuan
2004, 30(02): 95-99.
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Based on A* heuristics search algorithms, two efficacious real-time methods for combat mission were presented. By instead of direct distance with fold distance, the expanded number could decrease and the searching rate could speed up. Adding virtual threats, the limits of minimize turning radius and entering direction could satisfy. Form flight speed and arriving time of the plane could get the largest distance to the target. In the process of expanding, cutting branch with the largest distance could meet the needs of the flight speed and arriving time. The presented algorithms ensure the survivability of penetrate threat reach the maximization. The simulation results show that the efficiency of the algorithms is rationality.
Graphical electromagnetic computing method research based on IGES files import
Ye Guopeng, Zhang Yunfei
2004, 30(02): 100-104.
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At different wave band and polarization, the high frequency RCS of a model was computed with the graphical electromagnetic computing (GRECO) method. The shadowed and eclipsed surfaces were identified by using the visualization hardware, and the unit normal to surfaces were got with 5 light sources through 2 times of illumination. While computing the mirror-scattering RCS, 2 Sinc-functions were used to avoid singular points in physical optics (PO) results and method of equivalent currents (MEC) was used to compute the reflection of the edges. The agreement of the final computation results with the experimental data indicates this method could be used to estimate the model's RCS quickly and effectively at engineering analyses. Having added the interface that can identify and read IGES files, the limit to the type of the modeling files is released and the GRECO method's application range is extended.
Motion analysis and simulation control of numerical controlled transverse stretching machine for aircraft skin
Li Weidong, Wan Min, Zhan Qiang, Xu Chengxi
2004, 30(02): 105-108.
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On the basis of analysis of the mechanism of a numerical controlled transverse stretching machine, the software of the mechanism motion analysis was developed by reverse solution method. And the model and motion simulation of this machine were built in UG software. The accuracy of the reverse solution software was verified by the comparison between the motion reverse solution and computer simulation. The combination of the FEM simulation of stretch forming process and the axes extension control of stretching machine was realized, which provides the technological basis of accurate control and efficient exertion for this machine.
Simulation design based on state-space for environment test equipment
Zhai Huanchun, Shang Na, Wang Jun
2004, 30(02): 109-113.
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To calculate the system capacity accurately in environment test equipment design, a simulation scheme was introduced. This scheme was based on distributed parameter model and the model was expressed in state-space. In the traditional design, refrigeration of loading was regarded as completeness atthe end of refrigeration course. As a result, the system capacity is calculated much greater than the actual need. Compared with traditional design, the simulation design scheme is more accurate in system capacity calculation. The simulation scheme can be applied to test and compare different control scheme too. It is of distinct meaning and efficiency in the initial design stage.
Field calibration technique for 3D surface non-contact measurement system
Zou Zhiyong, Li Xiaoxing, Zhou Xianbin
2004, 30(02): 114-117.
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A simple field calibration technique was described to calibrate binocular vision senor for 3D measurement. The technique only required two cameras to observe a planar pattern shown at one position, and it did not need assistant structures. There were many control points printed on the planar pattern, through these control points to compute the homography between the model and its images. By combining evolutionary optimization strategies to get the principal points of two cameras, the focal lengths and the external parameters can be computed from homography. Compared with classical techniques, the proposed technique is simple and easy to use, and is applicable to field calibration.
Development on database of aircraft sheet metal forming
Wan Min, Li Xinjun, Liu Yufang, Jiang Yong
2004, 30(02): 118-121.
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To coordinate deeper technology renovation for aeronautic industry and elevate the conventional aircraft sheet metal forming process with information technology, based on a great deal of data and information from the aircraft manufacturing, pre-research, sheet metal forming manual, and process tests in aeronautic industry, a system of aircraft sheet metal forming database (Ashbase) was developed using PowerBuilder software and Sybase database management system. This system includes the data and information about the sheet properties, forming processes, tools and dies. And the methods for designing and realizing the design idea, general structure, system function, and data show of this system were analyzed.
Object-oriented undirected graph model in P&ID design system
Hao Guoshun, Liu Jinghua, Li Shicai
2004, 30(02): 122-126.
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When developing P&ID aided design system, the logical topology information between entities needed to be represented. In order to avoid the complexity of importing additional abstract entities, a new model is designed in which the logical topology information is united to the primary entity's data structure. This model has been successfully practised. The modeling process of P&ID undirected graph model from piping network graph was presented. After analyzing the characters of P&ID undirected graph, it points out what should be paid attention to when applying the model and how to extend the undirected graph.
Research on GHP model with constrained departing and landing capacities
Luo Xiling, Zhang Qishan
2004, 30(02): 127-130.
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The ground-holding problem (GHP) model with constrained departing and landing capacities was presented. This model solved the cases including the multiple runways, the international arriving/departing capacities and the consecutive flights, which are not covered in the single runway GHP model. The solving algorithms were given. The influences of the air/ground holding costs ratio and the arriving/departing weight ratio on the air traffic management decision were discussed. Simulation results prove the validity of the model.
Performance analysis and improvement of phase gradient autofocus algorithm
Chen Qi, Li Jingwen
2004, 30(02): 131-134.
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The realization of phase gradient autofocus (PGA) algorithm was described. Based on the analysis of the shortcoming of PGA and the study of the roles of the basic steps of phase gradient autofocus algorithm, two methods were proposed to improve the performance of the PGA algorithm. First, a new way to select window width was developed, which can accelerate the convergence of the autofocus; second, by selecting the appropriate row to processing, the effect of convergence of focus is good even under the condition of low SNR(signal-to-noise rate).
Cushioning properties of polyurethane syntactic foam
Yuan Yinglong, Lu Zixing
2004, 30(02): 135-138.
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Syntactic foam is a new kind of foamed polymer. It is very important to value its cushioning properties. On the basis of static and dynamic stress-strain curves of polyurethane syntactic foam, their cushioning curves were calculated and their cushioning properties were valued. The results show that the calculated minimum cushioning coefficients were almost the same in the case of static and dynamic loading. In addition, the effect of density and glass micro-spheres content of syntactic foam on the cushioning properties has been discussed at the same time.
Combined design and analysis of durability and damage tolerance for flight structure
Chen Bo, Bao Rui, Zhang Jianyu, Fei Binjun
2004, 30(02): 139-142.
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Based on existing durability and damage tolerance analysis method, a new way of flight structure design and analysis by synthesis was presented. It solves the problem that designing with durability or damage tolerance method separately will affect the optimization design for the flight structure. The analysis flowchart of this method is also given. Besides of using life and safety analyzing, structural weight and the inspection and maintenance were discussed. It can be used to increase the maneuverability and economy of the new flight structure. In addition, a calculation example is presented to validate the feasibility of this new method.
Study on reliability for flight control system under influence of thrust misalignment
Chen Yunxia, Sun Yufeng, Duan Chaoyang
2004, 30(02): 143-146.
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Thrust vector misalignment is an important factor, which causes trajectory scatter and affects missile reliability. In order to find design defect and enhance system reliability, the technique of integrated analysis of performance and reliability under the thrust's random misalignment was put forward. The disturbing moments were deduced and established. The algorithm process of reliability simulation, approach of implementation and formulas of computing reliability were given. The method was verified by X-missile's flight control system.
Numerical analysis of heat transfer in typical turbine blade cooling configuration of ribbed passage and pin fin arrays
Zhou Jianxing, Tao Zhi, Wu Hong, Ding Shuiting
2004, 30(02): 147-151.
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Numerical simulation was used to investigate the heat transfer of a typical turbine blade cooling configuration of ribbed passage and staggered pin fin arrays. Numerical results indicate that the distribution of heat transfer coefficient lacks of uniformity in the pin fin region. Calculation shows that blade top and root regions have much higher heat transfer coefficient and so is the area near ejection holes, whereas much lower heat transfer coefficient is observed for the central region of the blade.
Mixed flow fields numerical simulation of ram air turbines with autocoarse pitch
Fang Xiangjun, Liu Siyong, Wang Ping
2004, 30(02): 152-155.
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The aim of numerical experiment of ram air turbines is mainly to simulating its adjustable-pitch aerodynamic characteristic on the actual flight-refuel conditions. The Baldwin-Lomax turbulence model and the Reynolds-averaged Navier-Stokes were used to simulate the 3-D internal and external mixed flow fields. The present paper also discussed the cause of load distributing on the blade surface and analyzed the main aerodynamic characters of the turbine flow fields. The simulation results were compared with the experimental results of wind tunnel. It was pointed that it can improve the ram air turbines performance by optimizing the blades shape near the hub region.
Visual modeling method for test inputs of real-time embedded software
Ai Jun, Lu Minyan, Liu Bin
2004, 30(02): 156-159.
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The simulation testing, a major technique for real-time embedded software (RTES), is used in many important fields. Based on the analysis of the characteristics of RTES inputs, a visual modeling method for inputs of RTES simulation testing was established. Three steps are abstracting the input class diagram, building the input sequence diagram and describing the test inputs. The unified modeling language modeling technique was applied in the method for its high understandability. Based on the method, the test script/data can be generated for RTES testing.
Study on active vibration control of piezoelectric intelligent flexible beam
Wu Dafang, Liu Ancheng, Mai Hanchao, Fang Yuanpeng
2004, 30(02): 160-163.
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The active vibration control of the flexible cantilever beam with PZT actuators was studied, and the principle and the method of theactive vibration control were analyzed. Using the independent mode space controlmethod, the active control experiment on the first-order and second-order mode vibration of the flexible cantilever beam was performed. The experiment results show that the damping of the flexible cantilever beam is increased significantly by introducing the active vibration control method, and the excellent vibration control effect is obtained.
QoS control framework with QoP feedback for real-time video
Pu Juhua, Xiong Zhang, Shi Xiaoyan
2004, 30(02): 164-167.
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The BEST-EFFORT internet can't meet such quality of service (QoS) requirements as bandwidth, latency, and loss of real-time video applications, so the application layer QoS control strategies, congestion control and error control, are widely used. A joint transport framework of real-time video that supports application layer QoS was presented. This framework involves not only network resources and their variations, but also the restrictions of QoS control on the video quality of perception (QoP). The fuzzy map from QoS to QoP is also considered to control the QoS more efficiently. As a result, this framework is promising to improve video application QoS on the BEST-EFFORT internet.
Numerical simulations of hypersonic three-dimensional chemical non-equilibrium flows
Ma Hui, Zhao Lie, Wang Famin
2004, 30(02): 168-172.
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High temperature chemical non-equilibrium phenomena have a great effect on the flow field around a reentry vehicle. A three dimensional Navier-Stokes equations were solved by implicit finite volume NND scheme. Both ideal gas viscous flow and chemical non-equilibrium flow were calculated for a sphere-cone at a small attack angle. The results of the two flows were compared and the effect of chemical non-equilibrium was analyzed. The result is in good agreement with the reference paper. That proves that our method and programs are effective and practical.
Discussion about seal test of electronics in GJB
Zhang D, an
2004, 30(02): 173-176.
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The problems about sealing test of electronics in GJB were analyzed. Improved methods were presented, which provide the references for controlling theseal quality of military products scientifically. Failure data from a seal test processed by some factory are given to illustrate the importance of strictly controlling test conditions.
Development of theories on polymer-based nanocomposites
Wang Kai, Zhan Maosheng
2004, 30(02): 177-183.
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A review of the development of theories on polymer-based nanocomposites was presented. Attention was focused on the researches of thermodynamics, kinetics and micro-mechanics of polymer/layered silicate nanocomposites. The theoretical investigation on polymer/inorganic particle nanocomposites were also involved. The dispersion mechanism of nano particles and the relationship between the dimensions of nano particles and properties of composites were discussed. The quantitative characterization of the influence of nano-sized filler on the polymer matrix is the most needed.
Design and implementation of short message gateway for vehicle monitoring systems
Yuan Cangzhou, Zhang Qishan, Liu Zhongkan
2004, 30(02): 184-188.
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Based on the study of short message communications model, a short message communications gateway was carefully designed and implemented so that the vehicular devices can connect to multi reporting centers conveniently and transparently. In order to improve the gateway's performance, the concepts of queue, hash, and buffer storing were used in the design, and the techniques of multithread,message communication, and ActiveX control were used in the implementation. Testand practical operation demonstrated the high efficiency and reliability of the proposed gateway, and they also confirmed the design concept and completion techniques.

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