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2011 Vol. 37, No. 7

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Optimization method of finite thrust emergency orbit maneuver for an earth observation satellite
Yu Peijun, Wang Wei, Li Jiancheng
2011, 37(7): 757-761.
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The optimal emergency orbit maneuver method for an earth observation satellite was studied, which uses the finite thrust model. The mission requirement of the emergency orbit maneuver was investigated firstly. A twice orbital maneuver technique was adequately chosen to make the algorithm universal. The finite thrust dynamic equation in the three-dimensional space that considering the J2 perturbation was derived. The time variable-s span was given by solving the Lambert-s problem. The genetic algorithm was used as the optimization method to get a time optimal result. An emulation example was given to verify the method. The result shows the method has a high precise and can be get in a short time so it is available for the emergency orbit maneuver mission.
Robust control law design for fixed-wing airplane coordinated turns
Wang Xinmin, Xiao Yahui, Deng Wan, Xie Rong
2011, 37(7): 762-765,781.
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Taking certain fixed-wing airplane as example, the controller structure of H∞ state feedback control combined with proportion integration differentiation (PID) was designed to solve the sideslips of coordinated turns. Based on the fixed-wing airplane linearization model, the application of H∞ state feedback in the lateral controller design was studied and the influence of roll angle and airplane speed on the turning radius was analyzed. The results indicate that the designs are feasible and effective, and theoretical analysis about the factors affecting the turning radius is correct .
Applications of X-ray pulsar based navigation in high precision orbit estimation
Huang Xianlin, Chen Zhengmin
2011, 37(7): 766-771.
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X-ray pulsar based navigation (XNAV) can provide spacecrafts with autonomous positioning service. The accuracy of standard XNAV is coarse, in addition to that the pulsar timing model error and clock error can cause an approximate static bias in measurement error. Simulation results shows that 2 pulsars are needed to achieve total observability when using XNAV alone; and only 1 pulsar is needed when using integrated navigation with XNAV and cross-link measurement. Integrated navigation can also improve the positioning accuracy by over 10 times, and limit the estimation error caused by the static bias to under 0.2 meters. With realistic noise settings, using only standard XNAV in orbit estimation, a positioning accuracy within 50 meters can be acquired with only 2 pulsars. When using integrated navigation with cross-link measurement, the single pulsar navigation plan can achieve a positioning accuracy of 5 meters, proving that integrated navigation with single pulsar in standard XNAV is an autonomous navigation method with high precision, low requirement and relatively easier to implement.
Analysis of non-linear stability of guided projectile using lateral impulsive thrust
Yang Hongwei, Dou Lihua, Gan Minggan
2011, 37(7): 772-776.
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The analysis of non-linear stability of guided projectile under the condition of high attack angle after lateral impulse was presented. Integral was applied to describe the equations of projectile motions, and consequently, the polynomial for cosine variation of the attack angle was obtained. By analyzing the polynomial, the issue of stability of the projectile angular motion was turned to be the one of calculating the negative roots of the polynomial.The sufficient condition for non-linear stability of the projectile motion was also presented according to the Hurwitz criterion. The result provides certain theoretical basis for both academic and practical fields for issues about predicting the flying state of a projectile under non-linear motion condition, and for those on designing impulsive executive mechanism.
Rapid trajectory optimization for hypersonic reentry vehicles with multi-constraints
Wang Junbo, Song Xun, Song Jianshang, Ren Zhang
2011, 37(7): 777-781.
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A rapid trajectory optimization was developed to handle the high dynamic and multi-constraints accompanying with hypersonic reentry vehicles. The equation of constraints in reentry process was established and the control variable of bank-angle was displayed as a subsection linear function of flight energy parameter during the process of trajectory optimization. The longitude constrained reference trajectory optimization was converted to a nonlinear optimization problem,and solved using sequential quadratic programming (SQP) method. The lateral motion was controlled by yaw angle tracking aspect angle and the error corridor of aspect angle was designed. The logic of back angle- reversal is developed to avoid traditional calculation by iteration. The simulation results indicate that the algorithm is able to generate a 10 000 km range reentry trajectory in about 5 s on the desktop computer. And the algorithm has fast calculation,high guidance precision and effective for implementation.
Integration of aeroramp injector/gas-portfire igniter insupersonic combustor
Yan Minglei, Wei Baoxi, Xu Xu, Shi Xinxing
2011, 37(7): 782-788.
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A novel hydrocarbon-fuel injection and ignition/flameholding system consisting of aerodynamic ramp(aeroramp) injector and gas-portfire was designed, which was investigated experimentally and numerically to figure out the supersonic flowfield and its combustion. Color schlieren and surface oil-flow visualization pictures were taken in the vicinity of the injectors to obtain a qualitative assessment of the injector flowfields. Results show that the assembly strengthen and elevate the streamwise vortex. Compared to lone aeroramp injector, the mixing efficiency is improved from 60 percent to 75 percent. Wall friction generats most part of the total pressure loss, but the loss produced by aeroramp and gas-portfire is a little. And the gas-portfire works as igniter and flameholder.
Vehicle following algorithm realization based on flexible curved bar
Zhang Xiaomei, Chen Weihai, Liu Jingmeng, Zhao Zhiwen
2011, 37(7): 789-794.
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To solve the tracking accuracy problem of vehicle following system, when the leader vehicle was accelerating or turning, a novel algorithm based on a virtual flexible curved bar was proposed to apply for vehicle following. A virtual flexible curved bar was supposed to connect the leader and the follower. The curved bar was as long as the distance between the leader and the follower, while the bar arc fitted the leader-s curved path. The radiuses of the short arcs were recorded sequentially as the radiuses of leader trajectory to make the trajectory smooth and continuous. An acceleration fuzzy set was designed according to the bar length and the safe distance to update the follower-s velocity, in order to avoid the kowtow phenomenon during the following motion. Finally, some simulations were implemented in the three-dimensional robot simulation software. The results show that the method can be used in reality and the trajectory tracking accuracy can reach below 1 cm.
Tough terrain walking algorithm for cockroach robot
Chen Bin, Wang Jianhua, Chen Weihai, Ren Guanjiao
2011, 37(7): 795-800.
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To solve bad system rigidity and weak bearing capacity of series connecting mechanism, the couple four-bar linkage mechanism was proposed, which can synthesis advantages of existing mechanism. The cockroach robot based on couple four-bar linkage achieved moving agilely, good rigidity, strong bearing capacity and decoupling control. Built the mathematical module of this mechanism, used basic theory of linkage and mathematical of robot analyzed the backward kinematics and forward kinematics of the cockroach robot, then got an algorithm to control it walk on the flat road. Used force sensing resistor (FSR) and photoelectric switches to check whether foots- end have stand on the road. For walking fast on the tough terrain, a new planning for the track of foot was proposed. An algorithm was designed integrated the kinematics which can achieve by C Program. At last an experiment was designed. The results verify the algorithm can control the robot walk on the tough terrain as fast as 10 cm/s.
Coverage-scheduling integrated routing in wireless sensor networks
Fu Yinfei, Xiong Qingxu
2011, 37(7): 801-804,838.
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By employing the most-constrained least-constraining (MCLC) algorithm and directed diffusion (DD) and low energy adaptive clustering hierarchy (LEACH) routing protocol respectively, the performance in terms of nodes energy consumption, the balance of the consumption and the network lifetime of the coverage-scheduling strategies based on the different minimum residual energy of the node among the set was observed. The relation of network lifetime and minimum remaining energy was investigated. A new general approach of coverage-scheduling was proposed. Simulation results show that the new approach can effectively prolong the network lifetime, and meanwhile implies a new approach to design coverage control algorithm and coverage-scheduling policy.
Multi-stages necking process and mechanism of precision thin-walled can
Chen Hui, Lang Lihui, Du Chuanjun, Luo Xiaoliang
2011, 37(7): 805-810.
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Based on the multi-stages necking process of the precision thin-walled can, the deformational behavior of the material in each stage necking process was analyzed, the first necking process and the subsequent necking process was distinguished, and the definition of the die angle was given out. The control law of necking stroke in each process was investigated and verified by utilizing numerical simulation. The experiment results using a special equipment were obtained, which indicate the diverse analytical basement between different necking process. The load computational formula of different necking stages were derived based on slab method, indicate the existence of optimal die angle in each necking process. The calculated load results coincide with the experimental results, and the change of the necking load along with variation of die angle was obtained.
Random encryption scheme based on variable S-boxes
Wang Wenhua, Zheng Zhiming
2011, 37(7): 811-816.
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How the variable S-boxes would affect the security of the block cipher was studied and a new block cipher using random variable S-boxes was presented. A new encryption scheme based on such block cipher was put forward: the structure of the original encryption algorithm was kept, the S-box was taken as a variable and variable S-box was used instead of the primary one, which could increase the resistance against those known attacks. The security evaluation proves the scheme secure. Furthermore, a discussion on the improvement about the generation of the S-boxes and structure of the algorithms was given.
Tension restrained workspace analysis for cable-driven parallel robot
Chen Weihai, Yang Yangyi, Wu Xingming, Chen Quanzhu
2011, 37(7): 817-821.
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Cable-driven 3-DOF(three degree-of-freedom)robot was free to rotate in the workspace. For the cable was unilateral which was only may be stretched but not be compressed. To control the robot better, it was significant to research the cable tension. By using the geometry and the matrix method, it was easy to analyze the assignment situation of cable tension. Under the density restraint-s condition, tension coefficient was proposed as the appraisal of the tension assignment. After obtaining the tension coefficient distribution map, it had a direct-viewing understanding of tension workspace, then the effective tension assignment optimization algorithm can be proposed; By the discussion of the influencing factor and the selection method-s of the smallest pre-tightened force, it may obtain the smallest real-time computation pre-tightened force formula, thus it would guarantee that the cable tension was at tightens in every condition; Finally, with the prototype-s strength examination system the tension feedback experiment was taken, which may confirm the above theory. Through analyses and research of the above several parts, it may actuate a synthesis and comprehensive understanding for the cable tension problem of four cable-driven three degree-of-freedom robots.
Precise docking control in unmanned aircraft vehicle automated aerial refueling
Wang Honglun, Du Yi, Gai Wendong
2011, 37(7): 822-826.
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The control scheme and strategy for unmanned aircraft vehicle automated aerial refueling were proposed based on analysis of the vortex effect of tank and the free oscillation of drogue. The improved reference trajectory generator and trajectory tracking controller for receiver were used for automated aerial refueling precise docking control. The linear quadratic regulator method was used to design the trajectory tracking controller, and all kinds of disturbance were considered. The results of simulation show this guidance control method has the capacity for speeding up system response and restraining disturbance; Furthermore, it meets the requirement of automated aerial refueling.
Nonlinear modelling and open-loop dynamatics characteristics for one hypersonic aircraft
Chen Jie, Zhou Shaolei, Song Zhaoqing
2011, 37(7): 827-832.
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Considering that the hypersonic aircraft nonlinear dynamatic system owns the characteristics of nonlinear output, highly coupled of state vector, a novel sliding surface observer and controller design based on Lyapunov function was presented. During the course of observer design, overload output sliding surface was adopted to consrtruct Lyapunov function to guarantee the astringency of observer, and observer plus matrix could be gotten. Then, dynamic surface adaptive backstepping was adopted to design control law, multi-layers nerual network adjust function was introduced to compensate the influence from the uncertain, and the robust terms were designed to solve the problem from approach error. The stability analysis and simulations demonstrate the good performance of the controller.
Flutter analysis of inflatable wings
Xie Changchuan, Wang Weijian, Yang Chao
2011, 37(7): 833-838.
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The stiffness of inflatable wing is determined by the internal pressure, so the static and dynamic coupling method should be established to solve the flutter problems of such wings. The structural stiffness and the normal modes should be calculated on the base of the static analysis. Then the unsteady aerodynamics can be calculated and the flutter characteristics of the wing can be analyzed using the traditional methods. For an inflated wing, the finite element model was created using membrane elements. The structure stiffness of the wing was derived by the static analysis and the normal modes were calculated. Then the flutter of the wing was analyzed. The results show that, as the internal pressure increases, each mode-s natural frequencies increases. Except for the typical bending and torsion modes, the chord-wise bending modes have low frequencies. The chord-warping modes can induce flutter besides the conventional bending-torsion flutter type. The critical flutter speed of the inflatable wing presents nearly linearity with internal pressure increased in specific range and the corresponding flutter modes dose not change as well.
Los information reconstruction of half strapdown seeker
Yang Baoqing, Xu Long, Yao Yu
2011, 37(7): 839-843.
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Optical detector of strapdown seeker was fixed rigidly to the missile body, and many traditional guidance information processing methods can not be applied directly. The half strapdown seeker was studied. According to its different structure, reconstruction algorithm of the line-of-sight(LOS) rate was derived for roll-and-pitch and yaw-and-pitch half strapdown seeker. The Influence factors and error transfer relationship for extracted accuracy of LOS rate were analyzed. Then the correctness of the algorithm was verified by Simulink.
Design and realization of all digital closed-loop system of Coriolis mass flowmeter
Wang Shuai, Zheng Dezhi, Fan Shangchun, Tian Jing
2011, 37(7): 844-848,854.
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The digital closed-loop system of Coriolis mass flowmeter (CMF), in which the field-programmable gate array (FPGA) and digital signal processing methods were used to realize stable and accurate closed-loop control, has good real time and high precision. The speed parallel component FPGA was adopted as core of calculation and control. The first in first out (FIFO) module was brought in the phase control, which change time difference by controlling the read and write request signals of FIFO, to realize the stable and accurate control of phase difference between vibrating and exciting signal. The amplitude was set rapidly and precisely by using nonlinear amplitude control manner with well adaption, which combined discontinuous and continuous amplitude control. It gets the good amplitude control to the vibrating signals, which was output stable by controlling. The measurement accuracy and stability were improved. The experimental results show that the dynamic response and stability of the system is improved. From the real-flow calibration tests, that CMF digital closed-loop is better than traditional analogue closed-loop in stability, dynamic response and repeatability. Furthermore, the measuring precision of CMF is enhanced.
Vehicle visual navigation algorithm based on detect of horizon
Fu Bingdao, Ding Wenrui, Wang Guangbiao, Li Hongguang
2011, 37(7): 849-854.
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Combined with the demand of vehicle’s visual navigation system and the features of aerial images, a horizon detection algorithm which is used by visual navigation and based on the similarity between regions of images and tabu search was proposed. A single frame extracted from aerial video sequences was delt with downsampling and noise reduction. Tabu search algorithm parameters, such as initial solution, were initialized. Tabu search algorithm combined with the fit function fit the position of horizon. Tabu search-s amnesty and convergence criteria were used to judge the value of fit function until it meet convergence criteria. The values of the bank angle and the pitch angle which decide the next parameter-adjusting interval, and send the results to control system were driven. Compared with the traditional visual navigation method and the methods based on Hough transform, the experimental results show that the proposed algorithm is no-reference, good real-time and robust.
Optimization of systematic calibration method for SINS in outer field—optimal six-position
Mu Yutao, Zhou Zhenwei, Fang Haitao
2011, 37(7): 855-860.
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In the static multi-positions calibration method for strapdown inertial navigation system(SINS), the precision of parameters estimate is influenced by the positions arrangement. For the six-position calibration method, nine initial measurement init error parameters, including accelerometer bias, accelerometer scale factor and gyro bias, were estimated. The relation between position arrangement and calibration precision of these parameters was established. Based on this relationship, the position arrangement problem was transformed to the optimization problem of Fisher information matrix. Furthermore, the optimal position arrangement was presented under some single criterions, which is called as A-optimality, D-optimality and E-optimality, respectively. Finally, a numerical example shows that the optimal position arrangements based on these criterions can provide better estimate for some parameters such as calibrating accelerometer bias and accelerometer scale factor.
AFDX based simulation of flight management system
Li Dachuan, Cheng Nong, Li Qing, Song Jingyan
2011, 37(7): 861-867,876.
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Modeling and digital simulation are important phases in the development cycle of the civil flight management system. The distributed real-time simulation structure of the flight management system was proposed. The core function modules of the flight management system including flight planning, flight guidance, trajectory prediction, performance calculation, navigation, navigation database and display were modeled and the simulation algorithms were developed. Based on the avionics full-duplex switched ethernet (AFDX) protocol, the simulation module of the flight management computer, integrated navigation system and automatic flight control system were designed and integrated into the distributed system. A generalized AFDX-based distributed simulation system framework of the flight management system was presented. Simulation results demonstrate that the distributed AFDX-based framework can be implemented in real time applications with improvements on the performance of the network.
HCI develop trend based on user-experience
Wei wei, Gong Xiaodong
2011, 37(7): 868-871.
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The rapid development of information technology and the expansion of web platform bring the new requirement and possibility for human-computer interaction(HCI) design. Through extending Maslow-s hierarchy of needs to HCI field, It was proprosed: the future HCI design will try to satisfy users- experience requirement in higher level, and "Human-Computer Interaction"will develop to the direction of "Human-(Computer)-Human Interaction".
Longitudinal frequency-domain equivalent matching method for flight control system based on short time Fourier transform
Ji Xiang, Xia Jie
2011, 37(7): 872-876.
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Based on short time Fourier transform(STFT), a study was carried out on longitudinal frequency-domain equivalent matching for time-domain data in flight control system. The input signals of the system were first decomposed by STFT to achieve those signals that most interest the pilots. Then fast Fourier transform(FFT) was used to extract the frequency spectrums of both input and output signals. From the achieved frequency spectrums, the response function was derived and was applied in the low-order equivalent matching to obtain the parameters of low-order system. This method increases the matching efficiency of both high-order and low-order systems, reduces the matching error and improves the evaluation results of flying qualities.
Modeling and analyze of the environmental factors of carrier-based aircraft catapult launch in complex environment
Guo Yuanjiang, Li Huijie, Shen Gongzhang, Yang Ting
2011, 37(7): 877-881.
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The process of carrier-based aircraft catapult launch was complex, disturbed by the motion of aircraft carrier, deck wind, disturbance ahead of the bow and ground effect. The condition of carrier-based aircraft catapult launch was described by the simulation model of motion of aircraft carrier, deck wind, disturbance ahead of the bow and ground effect. The simulation model considering the condition of circumstance was composed of the model of plane and the model of circumstance condition, as the added factor. The results indicate that ground effect increases the flight path sinking, and the deck wind can help to decrease the flight path sinking during the catapult takeoff process. In addition, the motion of aircraft carrier has some important effects on maximum sinking and angle of attack.
Binocular stereo vision navigation for electric VTOL aircraft
Zhang Bohan, Cai Zhihao, Wang Yingxun
2011, 37(7): 882-887.
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A stereo vision-based navigation method for the electric vertical take-off and landing(VTOL) aircraft to wander safely through an unknown dynamic indoor corridor was researched. The aircraft uses two cameras to obtain images from different locations, and then the theory of binocular stereo vision was used to restore the 3-D coordinates of the feature points in front of the aircraft. Corner matching method was applied to calculate the disparity of the detected corners on the wall. Thus, the horizontal position of unmanned aerial vehicle(UAV) in the corridor was revealed. The area-based stereo matching algorithm was presented to get the dense disparity map of the original image pair, then obstacles were extracted from the disparity map and the navigation points were generated for the UAV to avoid obstacles. Preliminary experiment shows that the method is feasible and can be used as a basis for further research.
Two-step anti-windup control of helicopter
Wang Qing, Wang Yong, Peng Cheng, Miao Lifeng
2011, 37(7): 888-894,900.
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The all attitude control and velocity track of helicopter with actuator saturation constraints was considered. A two-step anti-windup control approach was proposed, which can be applied to open-loop unstable systems such as helicopter. Without consideration of saturation constraints, H∞ loop shaping inner and outer loop controller was given. The inner loop achieved all attitude control and channels decoupling, while the outer loop realized velocity tracking. With consideration of saturation constraints, the design of anti-windup compensator was proposed to reduce close-loop performance degradation caused by saturation. L2 stability of the proposed anti-windup control system was proved, and give potentially less conservative of anti-windup compensator by loop transformation and multiplier theory. The simulations of UH-60 Black Hawk helicopter show the effectiveness of the proposed anti-windup control method.
Determination of damage tolerance and remaining lifefor aeroengine crankcase
Qing Liye, Wu Sujun, Zhao Haitao, Liu Ying
2011, 37(7): 895-900.
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In order to ensure the safety of aircraft, fracture assessment for an aeroengine crankcase was carried out. Based on finite element method, a model for the local crankcase fitting seat was established and the geometry factor Y for different crack lengths was obtained. Using the procedure of BS7910, crankcase damage tolerance was calculated and verified by test, the critical allowable crack length is 84.8 mm and the remaining strength decreases with the increase of crack length. The allowable crack dimension and residual strength of weld are smaller than that of parent metal. The test results are in good agreement with the calculated results when crack is small. The remaining life of crankcase was also calculated using Paris formula.
Context aware and group based access control
Yao Quanying, Yao Shuzhen, Huang He, Tan Huobin
2011, 37(7): 901-906.
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Role based access control(RBAC) mainly depend on role given by the theme to achieve the protection of natural resources. In the control of the permissions, execution context, how the customs organize and manage were not taken into account.In order to adapt dynamic requirements of the application environment and to make the management of customs more convienent, RGBACC model was put forward. RGBACC model add "context-aware"and "user group management" to RBAC model. The context information ralated security from application environment was obtained to dynamically change the user-s permission. To the customs who have the same function, RGBACC model can manage them unifiedly,at the same time,it maintain the advantagement of traditional RBAC model.

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