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2007 Vol. 33, No. 03

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Flight loads analysis of longitudinal maneuver using experimental aerodynamic forces
Yan De, Yang Chao
2007, 33(03): 253-256.
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A method synchronously computing longitudinal maneuvering flight and flight loads based on nonlinear wind-tunnel test aerodynamic forces (experimental aerodynamic forces for short)was proposed. The coefficients of lift and pitch moment of experimental aerodynamic forces were introduced into the longitudinal maneuvering flight computation by use of surface spline, and flight loads on overall aircraft were elastically corrected based on pressure distribution of experimental aerodynamic forces simultaneously. Elastic loads were obtained utilizing linear aerodynamic influence coefficient matrix. The aerodynamic forces were also presented using double-lattice method (theoretical aerodynamic forces for short). The computed results using experimental and theoretical aerodynamic forces were compared. The results show that the maneuvering flight based on experimental aerodynamic forces is more reasonable and the change of flight loads using theoretical aerodynamic forces may be incongruous with that using experimental aerodynamic forces during maneuvering flight.
Characters on kinetics energy of debris cloud in spacecraft
Jia Guanghui, Huang Hai
2007, 33(03): 257-260.
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To assess damage by debris cloud after orbital debris impacts and perforates pla te of spacecraft, and to use adequately LS-dyna/SPH(Smoothed Particle Hydrodyna mic) computer simulation result of the orbital debris hypervelocity impacting th e plate, depending on the result about 9.53mm aluminium sphere impacting 2 .2mm aluminium target at 6.64km/s, debris cloud kinetic energy per area (DCP KE) and DCPKE formula was put forwarded after statistically cumulating of debris particles behind plate. DCPKE includes kinetic energy of all particles in debri s cloud and define the damage ability in area of plane behind spacecraft plate perpendicular to the impacting direction. DCPKE can be used to describe rule of debris cloud kinetic energy, which decrease with the distance. Depending on co mputer simulation of several impact velocity cases, the DCPKE curves were gained to show difference of impact velocities. DCPKE was also used to analyze materia l strength model influence, it can show quantificationally difference betwee n two material models.
Design of secondary-divergent vectoring nozzle based on secondary fluidic injection
Zhang Yongsheng, Wang Yankui, Yu Xiaowei, Deng Xueying
2007, 33(03): 261-264.
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Secondary-divergent vectoring thrust nozzle based on secondary fluidic injection was designed and the performance of vectoring thrust nozzle was studied by using computer simulation method. Several parameters, such as the angle of secondary-divergent section, the ratio of secondary fluidic injection pressure to main flow pressure, were taken into consideration in analysis of the nozzle performance. As a result, several conclusions were drawn from the above investigations. Firstly, the vectoring thrust is mainly caused by the secondary fluidic injection on the secondary-divergent section. The performance of nozzle with secondary-divergent section is better than that of nozzle without secondary-divergent section. Secondly, vectoring angle increases with the increasing of angle of secondary-divergent section and the maximum of vectoring angle reaches 39°. Finally, the vectoring angle increases with the increasing of the ratio of secondary fluidic injection pressure to main flow pressure.
Hypersonic combined cycle engine concept with tandem layout
Chen Min, Tang Hailong, Zhu Daming, Zhu Zhili
2007, 33(03): 265-268.
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Hypersonic turbo/ramjet combined cycle engine concept with the t andem layout was investigated to ensure that the civic aircraft can work reliabl y under a wide range of flight envelope(Ma＝0~5,H=0~30km).A non-linear combin e cycle engine model controlled by multiple variables was developed and verified . Based on it, an optimized scheme was then worked out after comprehensive evalu ation on the propulsion system integration via the parametric cycle analysis and performance cycle analysis. This scheme is favorable to the reduction in system dimension and weight, the adjustment of the shared inlet and exhaust nozzle, as well as the stability of the ram combustion. Transient simulation on the turbo/ ram mode transition was also conducted. Results show that stable mode transition could be acquired through proper modulation of five variable geometries and the fuel flow.
Optimization design of wing-s thickness and twist angle using Euler equations
Li Yan, Zhu Ziqiang, Wang Xiaolu, Chen Zemin
2007, 33(03): 269-272.
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With the goal of maximizing lift-to-drag ratio, the optimization of three-dimensional wing-s section thickness and twist angle is discussed. Euler equations as flow field sovler and Powell method are used as design tools, and the wing-s aspect shape and airfoil are fixed. The thicknesses of wing sections on the semi-wingspan relative position of 0.1, 0.2, 0.3, 0.8, 1.0, with the additional twist angle are chosen as the optimal control factors. The distribution of wing-s thickness and twist angle is obtained on the subsonic conditions with relative high lift-to-drag. The subcritical and supercritical computation of Lockheed-AFOSR wing B cases show that nonlinear distribution of thickness and negative twist angle could ameliorate the condition of flow field around the wing, which leads to higher lift-to-drag ratio, the optimization method is effective.
Optimal Lambert two-impulse transfer using genetic algorithm
Chen Tong, Xu Shijie
2007, 33(03): 273-277.
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Numerical solutions of Lambert two-impulse orbital transfer with unfi x ed initial position and transfer time were studied. The velocity increment versu s initial position and transfer time were showed in the 3-dimensional plots or 2 -dimensional sections, which are valuable for the practical designing tasks. Base d on the numerical solutions, the optimization problem of Lambert two-impulse or b ital transfer was then proposed and solved by genetic algorithm(GA). The goal w as to find the optimal initial position and transfer time to minimize the weight ed sum of fuel and time. This method was tested in two examples: one was the fue l optimal transfer between coplanar circular orbits, in which the computing resu lt based on GA was compared with that of Hohmann transfer. Another was the fuel and time optimal transfer between elliptical orbits of restricted initial positi on. Results indicate that GA is valid to solve the optimal transfer problems.
Analysis of heat sinking vest with phase-change material
Fu Yang, Qiu Yifen, Ren Zhaosheng
2007, 33(03): 278-281.
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To investigate the thermal protection effects of a heat sinking vest w ith phase-change material in high-temperature and high-humidity environment a nd the feasibility of numerical computation of heat transfer to the vest, based on the analysis of heat and mass transfer characteristic about the accouterments, a thermodynamic model was set up with the enthalpy method. The uniform energy equ ation was constructed for the whole domain, and the implicit difference equation was used in every node, the distribution of enthalpy was solved by numerical me thod. Simulation technique of the thermal system was established with the combin ation of human body thermal regulation model. It was used to analyze the accoute rments. A experiment was carried out to validate the final computer results, and the experimental and computer results were tallied well. The results indicate t hat using numerical method of phase-change material in heat transfer of vest is credible and appropriate.
Search method of dipping sonar on ship borne antisubmarine aircraft
Bai Jing, Han Liang
2007, 33(03): 282-285.
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To aim at the enemy submarine's linear elusion in the mustering instance of the ship borne antisubmarine aircraft, a forecasting search method b ased on the cooperation of two ship borne antisubmarine aircrafts was proposed.T he initiatory detecting spot was confirmed grounded on the definite detecting su rplus and the maximum combinable detecting angle. Through forecasting the enemy submarine′s voyage at the moment that the ship borne antisubmarine aircrafts wor ked, an arc search path was formed, which ceaselessly enlarged the radius and ap posed the orientation of the dipping sonares. The search method was simulated an d validated by Matlab. The success probability of the method is more than 70%. S o the search method possesses the reference meaning to the actual ship borne ant isubmarine aircrafts.
Target assignment in BVR air combat
Gao Yong, Xiang Jinwu
2007, 33(03): 286-289.
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Aiming at the key problem of threat estimation and target assignment in beyond-visual-range(BVR) air combat, a new non-parameter threat estimation model was formulated based on characteristics of BVR air combat, which takes into account aircraft-s combat effectiveness and situation superiority including angle superiority,distance superiority and velocity superiority. A new multi-target assignment algorithm was put forward on the basis of the threat estimation model. The new multi-target assignment algorithm emphasizes the cooperating and supporting process during BVR air combat and can be calculated easily. Simulation is carried out and the result shows the validity of the algorithm.
Flow and heat transfer in rotor-stator system with pre-swirl angle of 30°
Luo Xiang, Xu Guoqiang, Tao Zhi, Ding Shuiting
2007, 33(03): 290-293.
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An experimental study of the flow and heat transfer characteristics in a pre-sw irl rotor-stator system was described. Pre-swirl cooling air thr ough nozzles with angle of 30° in the stator flows radially outwards and leav es system from the clearance between rotor and stator. The distributions of the pressure on the stator surface, temperature, local and averaged Nusselt number o n the rotating disk surface were obtained from the tests. The experiments reveal that the pressure on the stator surface increase as the radius and also increas e as rotating speed. The local Nu number will keep invariable when r＜0.7R(R is effective radius of rotating disk) in the rotating disk surface, but it will inc rease rapidly as radius when r＞0.7R. The cooling flow rate have more effects on average Nu number than rotating speed in this pre-swirl angle.
Fuzzy gain scheduling control for electro-hydraulic servo velocity system
Ma Jungong, Wang Shifu, Wang Zhanlin
2007, 33(03): 294-297.
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Considering the nonlinear and the parameters variability, which vary widely with the working condition in the electro-hydraulic servo velocity system, fuzzy gain scheduling controller was developed. Based on the change of output error and its differential, the PID(proportion integral differential)parameters of controller were changed online by fuzzy reasoning in order to adapt the variety of set point and this made the control parameters reach the global optimization, solved the local optimization problem in the common gain scheduling. In the course of determine membership function of P and I, exponential function was introduced and this ensured the fast response and stability of system. Test results indicate that comparing with PID, the method accelerates the dynamic response, reduces the overshoot and load turbulence effectively too. So it is very validity for nonlinear system and the mathematic prototype system that can-t be built easily.
Neighborhood-aided trace method in improving efficiency of ray tracing
Huang Minjie, Li Wei, Wu Zhe
2007, 33(03): 298-301.
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In order to improve the success rate of scattering point search, the neighbors of the reference elements in reference paths were considered while the scattering points were not found on the reference elements, and the single reference path was also doubled to increase the efficiency of ray tracing. The application of this neighborhood-aided trace method in spline curve targets was also considered. The compatibility and hardware resource requirement were discussed, and the theoretical upper limit of the efficiency was given. The computing experiment on two typical targets was conducted. Results show that, this method could reduce the computational cost to 1/3 of original by decreasing the true and all-over tracing times. It also proves that this method had high stability and applicability to the complexity of targets, and overcomes the disadvantage of the traditional method which is sensitive to the ray tube division.
Reliability of fault tolerant control system with Markovian parameters
Gao Fei, Zhang Hongyue
2007, 33(03): 302-306.
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Fault tolerant control system with Markovian parameters(FTCSMP), as a model of active fault tolerant control system(AFTCS), was used to analyze the system stability in several papers. However, little research was on the reliability of FTCSMP. FTCSMP model was used to evaluate the reliability of redundant sensors monitored by fault detection and isolation(FDI). In this model, two homogeneous Markov stochastic processes with different state spaces were defined: one represented system components failures and the other represented the decisions of the FDI process. Based on Markov theory, the reliability and safety of the sensor/FDI unit were studied. When system fault process and FDI process of FTCSMP were both birth and death process, fault detection delay was divided into two kinds: effective and ineffective. The influence of both kinds of delay to the unit reliability and safety was analyzed. A numerical example of dual redundant inertial navigation system was given to show the usefulness of the proposed theoretical results.
Trajectory tracking control of three-DOF planar under-actuated manipulator
Liu Shengping, Wu Licheng, Lu Zhen
2007, 33(03): 307-310.
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The trajectory tracking control of a three-link planar under-actuated manipulator was presented. The third joint of the manipulator was passive. The dynamic constraint on the free link was shown to be second-order nonholonomic. Motion equations of the system were transformed into high order chained form using some global coordinate and input changes. A time-varying feedback controller was proposed to force the under-actuated manipulator to globally asymptotically track a reference trajectory. The control development was based on the current popular integrator backstepping technique. The method breaks down nonlinear system into low dimensional systems and simplifies the controller design using virtual control inputs and partial Lyapunov functions. Simulation results show the system can stably converge to a desired trajectory and demonstrate the effectiveness of the proposed control law.
Video quality assessing model based on single image quality with different weights
Chang Qing, Tong Yubing, Zhang Qishan, Wu Jinpei
2007, 33(03): 311-314.
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Concerning HVS (human visual system) physiological characteristic with the temporal-spatio correlations of video sequence, a video quality assessing model was proposed based on single image quality with different weights. Single image quality was assessed by using NN (neural network) and SVM (support vector machine) with PSNR (peak signal to noise ratio) and SSIM (structure similarity) as two indexes describing image quality. Video quality was assessed by using the quality of each frames in the video sequence with different weights. Those weights described motion and scene changes in the video. The monotonicity of the method for images & video is 7.42% and 10.47% higher than that of PSNR and RMSE (root mean square error) is 35.90% and 10.48％ higher than that of PSNR at least. The results from simulation experiments show the model is valid.
Fuzzy-PID double mode control of ultra-precision AC servo syst em
Lu Zesheng, Zhang Qiang
2007, 33(03): 315-318.
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It is difficult to establish mathematical mode for AC servo system , because it has several disadvantages, such as parameters varying as time, load disturbing, motor being non-linear, and so on. Fuzzy control need not establis h the mathematical mode of controlled plant, but steady state precision is bad. A fuzzy-PID double mode controller was presented, which combined fuzzy controlle r and PID controller. Different controller was adopted in different domain, so th e double mode controller combined the advantages of fuzzy controller and PID con t roller, and get rid of the disadvantages of them. The double mode controller is easy to realize. Experiment results show that the fuzzy-PID double mode controller reduces settling time by 33.7% without overshooting and decreases tra cking error by 47.2% in comparison to standard PID controller.
Jitter compensation system in solar X-EUV imaging telescope
Zhang Xin, Su Donglin, Li Baoquan, Peng Jilong
2007, 33(03): 319-321.
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The constant attitude control motions of the satellite often result in a platform that is not stable enough for mounting a high-resolution telescope. The jitter compensation system commands the CCD camera to shift one phase in the appropriate direction so that light from a point of the sun will continue to fall into the same CCD potential well. The CCD pixels phase shift along the detector-s columns which are aligned parallel to east-west. The high accuracy sun sensor (HASS) uses two reticles, which one is for each axis to determine the relative position of the sun. Only one axis of the HASS data is used for motion compensation. The north-south pointing errors are significantly smaller then the east-west errors, and are not compensated for by the system. The jitter compensation system incorporates HASS that is used in a semi-closed loop system to shift the CCD potential wells in order to compensate for jitter in one dimension. The motion compensation system can remove the solar "drift" and the solar array jitter during the exposure, and the X-ray imaging performance will be improved.
High-accuracy measuring system for position and attitude in pushing-bridge construction based on machine vision
Li Chao, Li Yunhua
2007, 33(03): 322-326.
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The feature of the present measuring system for position and attitude in pushing-bridge construction was analyzed and the system’s primary problems were specified. Directed by all the problems and on-site requirements, a kind o f photoelectric measuring system composed of CCD sensors, laser collimator and i nclinometer was developed based on computer visual feedback. After the system’s mathematical model has been built, the hardware work station was finished. In t he process of software functional modules’ development, such key technologies a s video acquisition, image processing and the implementation of multiple serial ports’ communication were introduced in detail. Characterized by high accuracy, real-time, simple operation, convenient maintenance and low cost, the measuring system can substitute for the past manual measuring operation. Furthermore, the system’s implementation also provides new technology for the design of other l arge-scale construction’s measuring systems.
General development platform for airborne equipments automatic test system
Sun Baojiang, Qin Honglei, Li Jie, Shen Shituan
2007, 33(03): 327-331.
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Aiming at the problems in the development process of automatic test system (ATS), a general development platform for ATS was presented. The platform joints the software and hardware design together, after inputting test points information and test strategy flows of unit under test(UUT) by interface, much of software and hardware design work can be finished automatically including instrument configuration generation, test unit adapter design and test program generation, etc. Design result will be transferred to the ATS runtime environment where ATS operator can test and diagnosis. An engineering application shows that the development platform can shorten the ATS development cycle, decrease design to factory implementation cost, and increase the degree of standardization and generalization of ATS.
BP networks method of handing-over point of KKV
Zhu Bo, Quan Quan, Cai Kaiyuan
2007, 33(03): 332-335.
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To reduce the missing distance and lessen energy consumption, the handing-over point with regard to proportional guidance law was analyzed for KKV(kinetic kill vehicle). The expected position of handing-over point was defined; the approximate nonlinear relationship between the expected position and the trajectory angles of the target was investigated by a BP neural networks. The expected position was obtained by the trained network. Simulation experiments prove that starting terminal guidance at the expected position could lessen energy consumption effectively as well as assure the required interception accuracy. The expected position obtained by this means is a real-time reference standard for adjusting the position of KKV during handing-over phase.
Attitude estimation method for micro attitude estimation system based on FD
Zhao Shifeng, Zhang Hai, Fan Yaozu
2007, 33(03): 336-340.
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The attitude of carrier with the tri-accelerometers and the tri-gyros respectively in a micro inertial measurement unit(MIMU) was estimated. Meanwhile, a strapdown inertial navigation system (SINS) was constructed and a Kalman filter was adopted to estimate attitude error derived from the attitude error equation. The remnants and the statistics were constructed to separate motion state of the carrier by fault detection (FD) method based on state remnant detection and to judge if the attitude estimated by accelerometers was credible. Data fusion method was adopted to fuse the attitude estimated by accelerometers and gyros respectively. So the dynamic performance of the attitude estimation system is guaranteed, and the precision of the attitude estimation is improved. Because micro electro mechanical system(MEMS) inertial components are adopted, the attitude estimation system is small, light, low cost, and suit to micro carriers especially.
Design of focal plane array of radio telescope
Lü Shanwei, Wu Dongmei, Wang Wei, Nan Rendong
2007, 33(03): 341-344.
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In order to increase the field of view (FOV) of the radio telescope, a new grid method named the conforming grid was proposed when the FOV of the telescope was analyzed. With this grid, the physics optical (PO) method is more accurate and fewer grids are needed compared to the conventional PO method. With the modified method, the focal field of WSRT telescope was computed. Based on the result, the dense focal plane array was designed for the telescope. The weights of focal plane array were given by the conjugate field method and the far fields of WSRT were computed. It is proven that a wider FOV, higher gain and aberration correction are obtained by dense focal plane array compared to the single feed.
Qualitative and quantitative analysis of fuzziness for stochastic structure performance
Chen Jianjun, Jiang Tao, Zhang Chijiang
2007, 33(03): 345-349.
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To overcome the deficiency that the safety membership function of a structure or a system in safety engineering sometimes involves subjectivity in the application of profust reliability theory, a preliminary study was made for finding out the rootstock of the performance fuzziness of a random system. The performance fuzziness for a general random structure system was quantified by translating random vectors into standard interval vectors, that is, the density functions of random vectors was intercepted by an equivalent horizontal cut set. A non-probabilistic reliability index was proposed to measure the fuzziness of the structural performance, and the index was defined in a convex domain a subspace of the standard interval vector space and in its extended space. Not only does the index offer to what extent the structure is safe but also depicts to what extent the structure has been failure. Consequently the index is proposed to characterize the fuzziness for the structural performance.
Subsequence matching algorithm between number trend sequences
Jia Suling, Chen Dangyang
2007, 33(03): 350-353.
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To overcome the demerits of traditional trend sequences- analysis in temporal data mining, two concepts that were number trend sequences and trend sequences unwrapping were put forward. According to features of number trend sequences, radians were used to represent the trends of line segments. DTW-QS(dynamic time warping quick searching) algorithm was designed to solve the problem of subsequence matching between number trend sequences. The algorithm included three parts: DTW sequential searching, the mechanism of restriction and the mechanism of redundancy control, and DTW-QS algorithm was evaluated via experiments.
Mean time to repair modeling oriented uni-mission for weapon system
Bi Jun, Wang Shaoping, Shi Jian
2007, 33(03): 354-356.
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As an important quantificational index for maintainability, the predication method and algorithm of mean time to repair (MTTR) are always dependent on experimentation and experience. Through the queue research of mission-furnishment-maintenance oriented to uni-mission, the MTTR model was to be established based on M/G/1 for repairable system which aim at the failure rate and repairable rate subjected to exponential rule, considering the mission requirement, reliability and maintainability. The corresponding quantitative method was also given. This model adhere to the basic conclusion which is drawn from maintainability theory based on reliability, and prevent from depending on a large quantity of statistical data at the beginning of design stage. The model and prediction method of MTTR can provide the quantitative maintainability index for purchaser on the condition of purchasing the weapon system.
Concept of testability determine test and relative method for FDR
Xu Ping, Kang Rui
2007, 33(03): 357-360.
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To solve absence problem of the method in determining the product-s testability level and find the difference between the practical testability situation and the requirements, the concepts of testability test and testability determine test was proposed. With the only consideration of fault detection rate (FDR), the method to establish fault character model (FCM) was given, which is based on the fault-function relation matrix and fault weightiness. Two-tuples FCM was illustrated and the flow to select sample based on two-tuples FCM in testability determine test was given. To simplify the workload and the complexity of the fault injection test, the equivalent relation between test samples were researched. The equivalent set and the equivalent injection sample (EIS) were defined. The relative method of result evaluation for FDR was researched. An example on a control system in some missile was illustrated, and the results show that the methods introduced are correct and feasible.
Experiments on surface structure for micro assembly using adhesive bonding
Ma Weimin, Jürgen Hesselbach, Huan Ji
2007, 33(03): 361-365.
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Micro adhesive bonding technology shows great potential in the assembly of micro-electro-mechanical system(MEMS) products. The quality of micro assembly using adhesive bonding is sensitive to two factors:the fluctuation of the adhesive volumes and the spread of the meniscus.In order to solve this problem, two surface structures on the bonding area were experimentally studied,which were the groove structure and meniscus-self-centering structure. Experiment results show that, the former structure has the ability of "fault-tolerance" to the volume of meniscus, and can overcome the influence of the mentioned factors on the quality of micro adhesive bonding; the latter structure enables meniscus to spread itself to the center of the groove, and thus to weaken the influence of the position error of micro assembly system. The two studied surface structures can be applied into the assembly of general MEMS products.
Application of evolutionary strategy in layout optimization of non-scale engineering drawing
Li Jiangtao, Liu Jinghua, He Tao
2007, 33(03): 366-369.
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The problem of unscientific layout and inferior readability currently exists in the non-scale engineering drawing which is generated automatically. Constraint conditions of engineering drawing were analyzed taking pipeline assemble drawing for example. The layout problem was simplified into the length adjustment of pipeline segment, and a multi-object optimization mathematical model was raised based on objects decomposing. Applying evolutionary strategy to solve the non-linear programming mathematical model, the express of layout problem, the operators of recombination, mutation, selection and termination condition were discussed. Results indicate that this method can meet the needs of readability and efficiency of real project, and also can be generalized into other layout optimization which has topological connections.
Visual servoing control in robot-assisted stereotactic neurosurgery
Liu Junchuan, Zhang Yuru, Li Zhen
2007, 33(03): 370-374.
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Positioning accuracy is one of the most important specifications in robot-assisted stereotactic neurosurgery. A visual servoing control method in robot-assisted stereotactic neurosurgery was presented to improve the overall positioning accuracy of the robot system. The position-based endpoint closed-loop visual servoing architecture was selected according to the characteristic of robot-assisted stereotactic neurosurgery. A visual tracking method utilizing the robot motion information was developed to locate the robot end-effector in the cameras images in real time. The visual servoing control law for the robot system was derived aiming at the problem that the tumor inside the patient′s head was unseen in the cameras images. With the visual servoing control method, the positioning error of the robot system was mainly caused by the target registration process. The effect of the robot absolute positioning error was eliminated and the overall positioning accuracy of the robot system was improved. Simulation of the clinical process and positioning accuracy test proved the validity of the method.
Auto-correlated charts based on dynamic Bayesian model
Cui Jingwei, Xie Liyang
2007, 33(03): 375-378.
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In statistical process control it is usually assumed that the observations taken from the process are independent. However, for many processes the observations are autocorrelated, and this autocorrelation can have a significant effect on the performance of traditional control chart. The problem of monitoring the mean of process in which the observations can be modeled as an AR(1) process was considered. A one-step forecasting autocorrelated control charts based on dynamic Bayesian model was presented for engineering practices. The principle and methodology to build autocorrelated control charts was described in detail. This control chart′s performance was compared to the performance of control chart based on process model, and the effect of process parameter estimation on the control chart was also investigated. When the process model is strong autocorrelation AR(1), the autocorrelated control chart has good performances with few samples. In this case, autocorrelated control chart was suggested instead of traditional control charts.

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