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2010 Vol. 36, No. 11

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New RAIM algorithm for identifying simultaneous double-faulty satellites
Zhao Lin, Li Liang, Cheng Jianhua, Lou Shangyue
2010, 36(11): 1261-1265.
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Because the traditional algorithms of satellite fault identification based on identifying threshold led to missed detection and false alarm, which reduced the correct identifying ratio, a new receiver autonomous integrity monitoring (RAIM) approach was proposed for identifying simultaneous double-faulty satellites. The geometry relationships between the proposed parity vector and faulty feature plane were used to identify the faulty satellites. Therefore the proposed algorithm was immune to the problem of identifying threshold and improved the correct identifying ratio. Computer simulation results indicate that compared with the existing traditional algorithms based on identifying threshold, the performance of faulty identification has a significant improvement, under the condition of simultaneous double-faulty satellites. With the proposed algorithm, the correct identifying ratio is as high as 90%. Moreover, compared with the reconstructed optimal parity vector algorithm based on identifying threshold, the new algorithm reduces more than 61.2% of the computational burden.
Comprehensive evaluation of pilot operation procedures for commercial airliner
Wang Lijing, Guo Fenfei, He Xueli, Xiang Wei
2010, 36(11): 1266-1270.
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Mostly by an elaborate set of pilot operation procedures(POP) crew can control planes successfully. Pilot may operate wrong under the inconsistent or illogical procedures,which can cause accident in flight. Normal procedures of approach and landing phases which come from flight crew operations manual of the Boeing 737NG airplane were divided into task function flow,then the hierarchy of index system was confirmed. The comprehensive evaluation index system of POP in approach and landing phases was established by consulting in-service pilots with Delphi method twice. Index weight factors were calculated by order relation analysis. POP was evaluated by fuzzy comprehensive evaluation and evaluation scales and values were calculated by weight factors and evaluation matrixes. A POP comprehensive evaluation method was proposed with the integration of functional flow diagram, Delphi, order relation analysis and fuzzy comprehensive evaluation. The method was used in evaluation of Boeing 737NG airplane POP of approach and landing phases. The result indicate the validity and rationality of the comprehensive evaluation method.
Effects of cylindrical hole accompanied with anti-vortex holes on film cooling effectiveness
Liu Xiaohong, Luo Xiang, Tao Zhi
2010, 36(11): 1271-1274.
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The primary focus was to further understand the flow and heat transfer aspects of a special film cooling hole arrangement where the main film cooling hole was accompanied by two parallel anti-vortex jet holes. The cooling effectiveness and the interaction between the main hot stream and the coolant jets were simulated and compared with the standard single hole arrangement. It is found that the presence of anti-vortex jets decreased the size and the strength of the counter-rotating vortex pair of the main coolant jet and so is its mixing with the main hot stream. The surface film effectiveness value is improved as expected. A bigger diameter of anti-vortex holes means more obvious improvement of film cooling.
Continuous stiffness modeling of 3-RPS parallel kinematic machine with special composite spherical joints
Cui Xueliang, Han Xianguo, Chen Wuyi
2010, 36(11): 1275-1280.
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A comprehensive continuous modeling methodology of 3-RPS parallel machine under dynamic load condition was developed and presented by considering the stiffness of legs and joints. The variational Jacobian matrix was used through vector differential and equivalent mechanism technique. Based on the screw theory, the force equation between the dynamic load on the mobile platform and its reaction forces on the legs and joints of the 3-RPS parallel machine was investigated and analyzed. The relationship between the pose (position and orientation) distortion of the mobile platform and the elastic deformation behavior of the legs and joints on 3-RPS parallel machine was established and analyzed by vector differential. A comprehensive dynamic stiffness model of the machine was developed by adding the total differential of the residual forces on the machine system. To validate the methodology, a numerical simulation was carried out. The result shows that the stiffness model of the parallel machine is affected by the outside load and the pose of the mobile platform. There is a large difference between the simple stiffness model and the integrate stiffness model near the workspace boundary of the parallel machine.
Performance analysis of IEEE-1394b bus isochronous transmission
Zhang Chunxi, Yang Yusheng, Wen Huaitao
2010, 36(11): 1281-1285.
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IEEE-1394b is a high speed data bus, which has been successfully utilized in avionics. Its isochronous transmission assures definite transmission delay of data, and is widely adopted in multimedia data transmission. To solve the performance evaluation problem of isochronous transmission, deterministic and stochastic Petri net (DSPN) model of IEEE-1394b isochronous transmission was developed. The proposed model considers the effect of bandwidth reservation and arbitration mechanism, which have remarkable effect on isochronous transmission performance, and the bus activity was described precisely. Through simulation, the relations among system’s throughput, average waiting time, packet size, packet arrival rate and node count were numerical studied. The limitation of IEEE-1394b isochronous transmission throughput was also obtained.
Film cooling characteristics on pressure side of rotating turbine blade
Li Guoqing, Deng Hongwu, Xiao Jun
2010, 36(11): 1286-1289.
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Experimental investigations were carried on to indicate the rotating film cooling characteristics in a 1.5 turbine stage. The length of the tested blade in chordwise and spanwise was 124.3mm and 99mm respectively with a 4mm film hole in the middle span oriented 28° to the tangential of the pressure side in streamwise. The mainflow Reynolds number Reg was 8×104. The blowing ratio varied from 0.3 to 3.0. Three rotating number (Rt) of 2.092, 2.324 and 2.448 were focused on. Air and CO2 worked as coolant to achieve the coolant to mainflow density ratio of 1.03 and 1.57 respectively. Thermo liquid crystal was employed to show the temperature distribution on pressure side surface which was captured by CCD. Results show that the film cooling effectiveness is increased with the blowing ratio rising while it is decreased with the Rt rising. Meanwhile, increasing Rt could lead the film trajectory to deflect more centrifugally. But it deflect less centrifugally with the blowing ratio rising under the same Rt. High density ratio could improve the film cooling effectiveness dramatically.
High accuracy data fusion of radar/infrared multi-mode guidance seeker with radar radome interference
Cao Xiaorui, Dong Chaoyang, Wang Qing, Chen Yu
2010, 36(11): 1290-1294.
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In order to improve anti-interference ability of radar/infrared multi-pattern composite guidance seeker with radome refraction, a new multiple model radome slopes estimate algorithm based on extended Kalman filter(EKF) was proposed in the three dimensional engagement scenarios. The slopes estimates were utilized in EKF to degrade the radome refraction in measuring line-of-sight and to get the local optimal estimates. Both of partial estimation results were integrated with sensor weighted coefficients depended on the sensor contextual information, which was introduced to characterize the reliability of sensor. The invalidity signals would be rejected. The performance of the proposed fusion algorithm was examined by four examples. Simulation results show that the algorithm can appropriately use radar/infrared measurement with radome slopes effectively estimating to enhance the estimating accuracy.
Lightweight and optimal design for 3-RPS parallel kinematic machine based on finite element method
Zhang Tianming, Han Xianguo
2010, 36(11): 1295-1298.
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The structure of the base platform and the links were optimized in order to reduce the mass and increase the stiffness of the 3-RPS parallel kinematic machine(PKM). The static stiffness of the PKM was analyzed with finite element method, using connector in the simulation of kinematic pair. From the analysis, the parts of base platform with low stiffness were identified; the deformations of the links and how they affected the deformation of the PKM were obtained. Ribs largely resisting the deformation were added, and the frame size was reduced to optimize the base platform. Deformation of the link was calculated by using cantilever model, and the dimensions of the link were optimized by minimizing the product of mass and the deformation. After the optimization, the mass and deformation of PKM were significantly reduced. The result can greatly improve the dynamic response and accuracy of the PKM.
Characteristics analysis of solid-liquid ducted rocket
Qin Lizi, Liang Shuqiang, Liu Yu
2010, 36(11): 1299-1302.
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The solid-liquid ducted rocket (SLDR) has advantages of solid ducted rocket (SDR) as well as liquid fuel ramjet (LFR). In order to analyze the characteristics of SLDR, a mathematics model was established and several proper parameters were presented. The characteristics calculation method was presented as well. According to calculating results, the specific impulse of SLDR is higher than SDR. When the mass ratio of liquid/solid propellant reaches 1, the specific impulse can be improved 1.82 times. With excess air coefficient increasing, the specific impulse increases firstly and then decreases. At off-design conditions, the specific impulse increases and then decreases with Mach number increasing. There is a critical Mach number that makes the specific impulse to be largest and this critical Mach number decreases with flight height. The thrust coefficient increases and the specific impulse decreases with fight height increasing.
Optimal adjustment method of rotor multi-dimensional vibration
Wang Kang, Wang Shaoping, Liu Hongmei
2010, 36(11): 1303-1306.
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Considering characteristics of non-linear and difficult to model for the rotor system, helicopter rotor dynamic balancing adjustment models was established by radial basis function(RBF)neural network. According to the constraints, the fitness function was established by using the helicopter vibration as objective function and the optimization variables were used by the adjustment parameters of rotor. The radial basis function neural network learning and optimization were used by the helicopter vibration and the adjustment parameters of rotor. Particle swarm optimization(PSO) algorithm was used to make a global optimization to find the suitable rotor adjustments corresponding to the minimum vibrations. The experimental results indicate that the particle swarm optimization algorithm is higher than the genetic algorithm in the aspect of efficiency optimization and the radial basis function combined with the particle swarm optimization algorithm can effectively achieve the helicopter rotor dynamic balance adjustment.
Analysis of aero engine vibration signal based on blind source separation technology
Qin Haiqin, Xu Kejun, Ou Jianping
2010, 36(11): 1307-1310.
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In order to improve the accuracy of vibration monitoring and fault diagnosis, a blind source separation frame which is combining mathematical morphology preprocessing and Fast ICA arithmetic was brought out based on the characteristics of dual rotors aero engine case vibration signal. It is that the original signal was preprocessed by open—close and close—open combinatorial mathematical morphology. The signal noise can be well filtered, but its fundamental form can be reserved. The Fast ICA arithmetic was used to get back the high and low rotor-s vibration waveform. The frame was used to analyse the real testing data. The result shows that the method can well respectively resume the high and low rotor signal frequency domain structure information. It is very helpful to improve the accuracy of fault location.
EVA glove strength under low temperature and pressure
Liu Heqing, Ding Li, Yuan Xiugan, Li Jing
2010, 36(11): 1311-1314.
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In order to study the effects of combined stress of glove pressure and low temperature on astronaut operation strength during extravehicular activity (EVA), the maximum grip strength and grip fatigue were selected as two indicators to evaluate the strength of manual performance. Fatigue was evaluated by the work done in grip test. The low-temperature and pressured experimental conditions in the grip test were simulated in the low-temperature simulation cabin using the liquid nitrogen and the vacuum pump. The results indicate that wearing glove has very significant effect on the maximum grip strength and grip fatigue. Pressure(29.6kPa,39.2kPa) has significant influence on the maximum grip strength compared with wearing glove under normal temperature and pressure. Low temperature has no significant influence on the maximum grip strength. However, pressure and low temperature have particularly significant influence on grip fatigue. Under the combined stress of both pressure and low temperature, the maximum grip strength and grip fatigue will be further influenced significantly. The combined stress of pressure and low temperature in space seriously reduces the strength of the astronauts. The effects of combined stresses should be considered in researches of the man-glove system during extravehicular operations.
Representation for RBAC model with description logic DLRBAC
Ma Li, Ma Shilong, Sui Yuefei
2010, 36(11): 1315-1319.
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A new description logic-based representation for role-based accesss control(RBAC) model was proposed. RBAC sets and relations were translated as concepts and roles in the description logic respectively. To express RBAC role default inheritance and constraint conditions, symbols that represented role composition and inclusion were introduced to the basic description logic language, such that some RBAC default inheritance properties, such as role hierarchy(RH) transitivity, user-role assignment(UA) inheritance and permission-role assignment(PA) inheritance, and some RBAC constraints, such as static and dynamic separation of duty relations, can be represented formally. By integrating default inheritance with constraints in one formal system, the new inheritance relations that violate the access control strategy can be limited with the help of description logic reasoning mechanisms.
Statistics on atomized feature of normal cloud model
Liu Yu, Li Deyi
2010, 36(11): 1320-1324.
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The cloud model atomization process was related to a larger hyper enctropy. Through statistical analysis of the overall trend of the cloud drops, the cloud drops dispersed over the course of hyper entropy increase. By analyzing the dispersion trend of cloud drops in each semantic ranges, it is indicated that the drops represent the core concept dispersed in a low speed. The atomization feature of the cloud model was summarized. The semantic range of the concept represented by the cloud model extended while the hyper entropy increased step by step. The cloud drops spread but the drops nearby the core semantic keep a high density. The atomization feature of the cloud model was used to model the data deviates from the normal distribution. A cloud with a large hyper entropy value represented the concept lack of consensus. For each parameter, the expectation stands for the core semantic value, the entropy represents the semantic range and the hyper entropy shows the degree of consensus of the different semantics ranges. The cloud model knowledge representation application range was extended.
Method for optimizing QFT robust control system
Jin Xianzhe, Wu Sentang
2010, 36(11): 1325-1329.
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A method for optimizing the quantitative feedback theory (QFT) robust controller was presented based on stochastic robustness analysis and design (SRAD) methodology, which solved the problems, such as inadequate robustness measures in existing optimization methods for QFT robust controller. With SRAD-QFT, the probability of instability and the probabilities of unsatisfied performances of the closed-loop control system were achieved by Monte Carlo evaluation.The stability robustness and performance robustness measurements for the closed-loop control system were provided by these probabilities, based on which the QFT controller and pre-filter could be designed simultaneously. The longitudinal flight control system design for a supersonic anti-ship missile using SRAD-QFT shows that this method can accurately descript the parametric uncertainty of the plant and provide the robustness measurements of the closed-loop control system. Also, it is suitable for designing the complicated system.
Numerical investigation of phase change thermal control unit for portable electronic devices
Wu Bin, Xing Yuming
2010, 36(11): 1330-1334.
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The thermal control unit(TCU) using phase change material(PCM) can well perform thermal control for portable electronic devices, and avoid it over heating. Two-dimensional mathematical model of TCU was presented, and numerical simulation was conducted to analyze its thermal performance. The results show that adding fins and filling with foam-PCM composite material can significantly improve thermal performance of TCU and satisfy the need of electronics working condition. Further, effectiveness of TCU by the two kinds of design was compared, and the design of filling with foam-PCM was superior to another one. The conclusion provides guidelines for portable electronic devices TCU design and optimization.
Precession period extraction of high-rate rotating projectile
Li Yimin, Su Donglin, Leng Xuebing
2010, 36(11): 1335-1338.
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Precession is conical motion that projectile axes rotate around the projectile velocity direction in flight. Precession is one of micro-motions in addition to the translation. Precession produces frequency modulation on the returned radar signal and induces additional Doppler shifts to the Doppler frequency shift caused by translation, called micro-Doppler effect. The mathematics of micro-Doppler signatures shows that the reflector radial velocity is the sum of the mass center radial velocity and the micro velocity. The reflector radial velocity contains the information about precession, which can be obtained by using the short time Fourier transform(STFT). The mass center radial velocity can be derived from polynomial expressions. The velocity subtracted from the reflector radial velocity gives the micro velocity.Time-domain and frequency-domain analyses were jointly adopted. The sliding window autocorrelation of the micro velocity was also used to measure precession period. Both computer simulation and the experimental results demonstrate the validity.
Finite element analysis of factors to thermal stress in thermal barrier coatings with orthogonal method
Li Zhiyong, Zhang Jianyu, Bao Rui, Fei Binjun
2010, 36(11): 1339-1342.
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The thermal stresses in room and elevated temperatures were studied in thermal barrier coatings (TBCs) which was coated at the outer surface of pipe specimens, using finite element method (FEM), and the Walker viscoplastic theory was adopted to depicting the stress-strain constitution in the ceramic layer. During the design of FEM analysis computation, the orthogonal design method widely used in experiment study, was used, and the contributions of four factors to the being of thermal stress were achieved. The results show that the four factors have the remarkable effect to thermal stress in TBCs, and the factor of thermally grown oxide is the most important, the stress changing rules of four factors are different in TBCs with the ascending of levels.
Design of rotation modulation AHRS based on MEMS sensor
Xu Yefeng, Lü Yanhong, Qiu Haitao
2010, 36(11): 1343-1347.
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In order to achieve a high-precision, low-cost attitude and heading reference system (AHRS),the approach of using rotation modulation technology based on low-performance micro electronic mechanical system (MEMS) gyro was proposed. Quaternion and three sub-sample algorithms were used to calculate the heading and attitude angles. Two kinds of alignment modes, self alignment and rapid alignment could be alternated. The self alignment was accomplished by Kalman filter based on velocity observation. The heading alignment accuracy would be better than 5° by using MEMS gyro with the drift about 30(°)/h. When the rapid alignment solution was used, the heading was provided by magnetic compass and the accuracy would be better than 0.4° when the magnetic compass deviation was compensated. Static and dynamic experiments results show that the rotation modulation approach can improve the precision of MEMS gyro by about 30 times, the output accuracy of the system is better than 1° within 1 h.
Dynamic analysis for lunar lander based on rigid-flexible coupled model
Lu Yuntong, Song Shunguang, Wang Chunjie, Zeng Fuming
2010, 36(11): 1348-1352.
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Based on the rigid-flexible coupled multibody dynamics theory, an analysis method involved three-dimensional solid modelling, finite element analysis and multi-body system dynamics analysis was proposed. With such a method, the landing dynamics model for a lunar lander was established and used to analyze the landing performance for a typical touchdown case in both Earth-s gravity and Lunar-s gravity (1/6 Earth-s gravity) environments. The results include the max strut stroke in both the primary struts and secondary structs, the lunar lander mass center-s max acceleration. The analysis results were contrasted with those from the shock testing, showing that the rigid-flexible coupled dynamics model has been correctly built and the analysis method is valid and efficient. The model and method developed can then be used for future evaluating the landing performance of the lunar lander. The landing performance of the dynamics model was analyzed in energy prospect, making up shortage of shock testing’s failure of doing energy prospect.
Vehicular DYC via SMC and system stability analysis
Zhang Wei, Ding Nenggen, Wang Jian, Yu Guizhen
2010, 36(11): 1353-1357.
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Direct yaw moment control (DYC) can generate the additional yaw-moment needed to maintain vehicle stability in the limit conditions so to improve the active safety of a vehicle-s handling. A nonlinear vehicle dynamic model which meets the requirements of vehicle stability control experiments was established, and a sliding mode controller (SMC) was designed. The stability of the SMC controller was proved with Lyapunov function. At last the stability and control effect of the SMC was verified by simulations in Matlab/Simulink. The simulation results prove the effectiveness of the control algorithm and suggeste that the robustness of SMC is better than that of proportional-integral-derivative(PID) control algorithm, which proves SMC better application potential.
Development of aircraft-design material-selection expert system
Lan Yuanpei, Jiao Qixiang, Guan Zhidong, Xu Guangxing
2010, 36(11): 1358-1364.
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Following a discussion on aircraft-design material-selection, a browser/service architecture framework of materials selection expert system, together with its implementation and prototype, was put forward. The system integrated rule-based reasoning, case-based reasoning and model-based method, and it could reason with a general inference engine. The inference engine’s function was implemented by a popular expert system development tool—C language integrated production system(CLIPS). When this system functioned, it worked in these three steps: reasoning for qualitative selection results, searching materials from material database and ranking the materials to obtain a selection result. User could access the system with browsers conveniently. Its effectiveness was demonstrated by a case of wing-spar materials-selection.
Weight coefficients calculation for evidence sources and it-s application in evidences fusion
Meng Guanglei, Gong Guanghong
2010, 36(11): 1365-1368.
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Evidences fusion is an effective approach for improving target identification. In order to solve the unreasonable results generated by conflictive evidences, the assessment principle for weight coefficients of evidence sources was proposed. The evidence distance concept was introduced and a calculation method for weight coefficients of evidence sources was proposed according to the assessment principle for weight coefficients of evidence sources. Evidences from multiple sensors were modified and added with these weight coefficients. As a result, evidences conflict is dissolved and unreasonable results are avoided. For the purpose of efficiently utilizing the transcendent knowledge and accelerating target identification, two evidence-fusion schemes were designed and the fusion complexation was analyzed. Simulations were carried out to test the two evidence-fusion schemes, and the results verify the validity of the schemes in target identification.
Numerical simulation of flow and heat transfer in swirl microchannels
Xi Youmin, Yu Jianzu, Xie Yongqi, Gao Hongxia
2010, 36(11): 1369-1372.
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Swirl microchannel heat exchanger has the potential to transfer high density thermal flux. It will have great application prospect in solving thermal control problem of aviation and aerospace high power density component. On the basis of experimental research, a numerical simulation of flow and heat transfer in swirl microchannels was conducted. The computation using the finite volume method was performed under different flux for several test sections with different channel structure. The flow stability in the swirl microchannel was analyzed. The variation curves of local friction factor and Nusselt number along flow channel were presented. The enhancing heat transfer in swirl microchannel was discussed with field synergy principle. The calculated mean heat transfer coefficients and flow friction factors were compared with experimental data. The results show that the secondary flow is the mechanics strengthening heat transfer in swirl micrcochannel.
Dynamic and flutter analysis of long-straight-wing based on equivalent beam model
Zhang Xu, Wu Zhigang, Yang Chao
2010, 36(11): 1373-1377.
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For a complex structure of multiple degrees of freedom (DOF), building a simplified model of equivalent structure can lead to rapid and effective structural analysis. The method of energy equivalence was used to make a long-straight complex structure of multiple DOF equivalent to a beam element in space, the stiffness and inertia characteristics of the equivalent beam were derived, and the total stiffness matrix and mass matrix were obtained by using the finite element method. For a wing model, using the equivalence method, stiffness values and inertia values of the equivalent beam had been gotten. Analysis of vibration and flutter was carried out, and their respective results were separately compared with the calculation results of MSC Nastran. The contrast shows that the equivalent modeling method significantly reduces the structural DOF, and that the relative errors of results are small. And its main parameter values can be conveniently modified. Therefore, the method can be applied to preliminary design and structural optimization design of aircraft.
Compact array antenna in Ka band for near-field scattering measurements
Wang Hui, Miao Jungang, Jiang Jingshan
2010, 36(11): 1378-1381.
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A four-element compact array antenna was designed operating in Ka band for near-field scattering measurements, and an approximately uniform amplitude and phase distribution in the near fields of array antenna was achieved. The radiating element consists of pyramidal horn antenna and E-plane metal-lens antenna. The feed network consists of magic T and bend waveguides, providing equal magnitude and phase signals for radiating elements. The lengthways length of the array is significantly reduced by employing array and E-plane metal-lens antenna, and the electrical performance is also improved. The near fields of array antenna was tested, and the test results were analyzed. In the plane 0.5 m from the aperture of the array with width equal to that of the array, the amplitude and phase ripples are around ±2.5 dB and ±25° respectively.
Adaptive feedback control design for hypersonic cruise flight vehicle
Li Huifeng, Li Zhaoying
2010, 36(11): 1382-1386.
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Because of strong nonlinear characteristics, modeling uncertainties and complicated flight environment, the control of hypersonic flight vehicle becomes a challenge. An approach which combines feedback linearization and adaptive control for a multiple-input-multiple-output(MIMO) nonlinear system with parameter uncertainty was proposed. Feedback linearization was used to obtain the linear input-output dynamics and a feedback controller was designed. The uncertain parameters were estimated online by an adaptive control law and the Lyapunov method was introduced to analyse the close-loop system stability. For the conditions of choosing different outputs, a discussion was made on how to remove the inner dynamics to avoid unexpected unstable dynamics. A hypersonic cruise flight vehicle longitude model was used to testify the reliability of the proposed approach. In order to control altitude and velocity channel, a feedback controller with adaptive online estimator was designed for the parameter uncertainties in vehicle model and atmosphere model. The simulation was operated to track the altitude and velocity step commands. Results show the controller has good tracking performance with rapid converge speed.

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