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2014 Vol. 40, No. 6

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Integrated guidance and control design for a class of missile with networked packet dropouts
Wang Qing, Qi Chengdong, Dong Chaoyang
2014, 40(6): 721-726. doi: 10.13700/j.bh.1001-5965.2013.0408
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An integrated guidance and control (IGC) algorithm for a class of missile with networked packet dropouts was researched. Considering that a number of ground-based radars were used to observe on the target simultaneously and the target information was shared with the missile through the network. Networked packet dropouts were described as the communication topology model between the missile and radars. The pitch channel IGC model including three cascaded subsystems was established. In this way, virtual controllers were designed for each subsystem. To guarantee the stability of the missile when packets dropouts occur, the corresponding filters were designed for the virtual controllers. An IGC algorithm was put forward by adopting sliding-mode control and back stepping control method. Sufficient condition to guarantee the bounded-input bounded-output (BIBO) stability of the system was simultaneously derived. Finally, simulation results demonstrate the effectiveness of the proposed method.
Optimization model of VTS radar station location problem
Cao Desheng, Lü Jing, Ai Yunfei, Zhang Lili
2014, 40(6): 727-731. doi: 10.13700/j.bh.1001-5965.2013.0706
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The location result of vessel traffic services (VTS) radar station has an important influence on the normal functioning of the entire system. The multi-level fuzzy comprehensive evaluation method was used to select the candidate points of radar stations. Based on the set covering model, a dual-objective optimization model was put forward. The first objective was to minimum the total cost, including the cost of radar stations and the line laying cost between the radar stations and the VTS center. The second objective was to maximum the total weights of multiple covered units. In view of the model, a genetic algorithm was designed. The numerical example shows that fuzzy comprehensive assessment may remove some of the candidate points, which makes the value of objective functions variation, however, it would increase the practical feasibility of the result. The program was run 10 times with stable calculation results, so the algorithm is convergent and stable, and the model is feasible.
Dynamic critical friction of landing gear shock absorber binding
Wei Xiaohui, Song Xiaochen, Li Lirong, Nie Hong
2014, 40(6): 732-736. doi: 10.13700/j.bh.1001-5965.2013.0418
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In order to explore the design criterion of landing gear shock absorber binding, based on the method in aircraft design manual, takeoff and landing system design, the static and dynamic critical friction coefficients of a certain unmanned aerial vehicle's main landing gear were analyzed. The analysis shows that the dynamic critical friction in yaw landing load condition and maximal spring back drag in tail sinking load condition are prone to bind. And then combined with the landing gear drop dynamic response curve, the physical meaning of shock absorber dynamic binding was studied. Research shows that the argument foundation of the dynamic critical friction analysis does not hold and oleo-damping force should not be included when calculating the critical friction coefficient. For the analysis of landing gear shock absorber binding in the state of a moment, it is more accurate that taking the method of static critical friction in aircraft design manual-takeoff and landing system design to check.
Development for portable system of solar cell parameters acquisition
Xiao Wenbo, Zhuo Rusheng, Cao Qijun, Cao Huaxiang
2014, 40(6): 737-741. doi: 10.13700/j.bh.1001-5965.2013.0428
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In order to fulfill rapid and accurate acquisition of the solar cell photoelectric characteristic eleven parameters (including the photocurrent, reversed saturation current, ideality factor, series resistance, shunt resistance, short circuit current, open circuit voltage, maximum output power, best working voltage, best working current and fill factor), a testing system, that consists of six parts (including the sun simulator module, control and processing module, electronic loads module, signal collection module, key input module and display output module), was developed. The main features of the system are that, programmable constant current and voltage electronic load and sampling frequency conversion technique are used to realize an accurate measurement of current and voltage, after integrating solar cell parameters analytical extraction algorithm into the digital signal processing chip, the cell parameters, for example, photocurrent, can be acquired conveniently. The results show that the mean square error of current-voltage curve fitting of a mono-crystalline silicon solar cell under different light intensities is less than 0.006 A, which proves that the obtained eleven parameters are correct.
Dent resistance test method and system for auto-body panel
Wang Liang, Li Dongsheng, Chen Lianfeng, Li Tao
2014, 40(6): 742-748. doi: 10.13700/j.bh.1001-5965.2013.0395
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For the auto-body panel parts characteristics, a test method of dent resistance was introduced. Based on the test method, an automatic tester system for dent resistance test was developed. The tester indenter can be adjustable with arbitrary posture in space and load reliably by integrating "5-axis motion + 1-axis loading". Control hardware system with "PC + motion controller" structure was constructed based on programmable multi-axis motion controller(PMAC). The corresponding control software was developed. Six-axis tester was controlled accurately. The normal vector of a test point on parts was obtained with one approximation method. The motion data of tester indenter adjustment from initial position to test point normal direction was calculated based on the principles of robot kinematics, so the tester was able to load automatically in normal direction of test point on panel parts. Calibration and application indicate that the testing system works stably and reliably.
2D/3D video conversion method based on piece-wise structure from motion
Liu Wei, Li Gongyan, Ding Kai, Wu Yihong
2014, 40(6): 749-755. doi: 10.13700/j.bh.1001-5965.2013.0437
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To alleviate the shortage of 3D media sources, a piece-wise structure from motion method was designed to provide depth cues for the 2D/3D video conversion. Videos were decomposed into subsequences of different scenes and key frames of non-degenerate were extracted in each subsequence with optimization criteria. On this basis, a piece-wise structure from motion framework was proposed and depth cues of scene sparse structures were obtained through an improved coupling self-calibration algorithm. Experimental results show that by local optimization after video segmentation, the proposed method can handle video shot containing multiple scenes based on structure from motion, and improve the efficiency of conversion effectively. Those mean the proposed method is suitable for the 2D/3D video conversion.
Short takeoff performance optimization based on simulation model
Wu Dawei, Li Hanbing, Li Shu, Hu Jizhong
2014, 40(6): 756-761. doi: 10.13700/j.bh.1001-5965.2013.0420
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Short takeoff performance is important for all kinds of special aircrafts because they can accommodate more pay load and get higher safety during short takeoff and landing than vertical takeoff and landing. Short takeoff simulation model was established for a small unmanned tilt rotor aircraft based on its longitudinal flight dynamics model. The genetic algorithm was applied to shorten the takeoff distance as objective function by optimizing the control variables. The results of optimization show that the takeoff distance can be minimized by suitable elevator control method and there is an optimal tilting angle of engine nacelles for any given gross weight to further shorten takeoff distance. In addition, continuously tilting engine nacelles according to optimized control method also benefits the short takeoff performance. Considering the essential mathematical characteristics of simulation model and optimization algorithm, this method can be generally applied to short takeoff performance optimization for any other aircrafts including conventional fixed-wing airplanes and helicopters.
Fuzzy robust tracking control within full envelope for unmanned aerial vehicle
Liu Zhi, Wang Yong
2014, 40(6): 762-768. doi: 10.13700/j.bh.1001-5965.2013.0396
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The fuzzy robust tracking controller within full envelope of unmanned aerial vehicle (UAV) was proposed for the problems of wide variation of aerodynamic characteristics, experiencing parameter uncertainty and external disturbances during the flight in large envelope. With fuzzy c-means clustering, the fuzzy T-S model approximating the dynamics of UAV within full envelope was constructed. Based on the augmented tracking system of airspeed and altitude, the constraint condition of fuzzy robust tracking controller was provided in terms of linear matrix inequalities (LMI) according to guaranteed cost theory with descriptor system based fuzzy Lyapunov function approach, and input-states stability was ensured. The control parameters were optimized via minimizing disturbance attenuation with less conservative and reduced computation complexity. The simulation shows that high accuracy tracking of airspeed and altitude desired instructions within full envelope is realized with strong robustness to parameter uncertainties and external disturbances.
Oil gap loss and mechanical efficiency of axial piston electro-hydraulic pump
Li Zhufeng, Shao Yunbin, Fu Yongling, Fan Dianliang
2014, 40(6): 769-774. doi: 10.13700/j.bh.1001-5965.2013.0438
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From the innovation perspective, the structure and working process of axial piston EHP were described. With various mechanical losses analyzed, the mechanical efficiency calculation model of EHP was established and the oil gap loss as well as mechanical efficiency varying with speed, pressure and temperature was respectively presented. The simulation at the temperature of 50 ℃, the speed of 4 000 r/min and the pressure of 28 MPa shows a relatively high working efficiency. The oil gap loss of EHP is 1.737%, which is much lower than the van and mechanical losses of motors in traditional motor-pump set. And the mechanical efficiency is 92.6%, which is higher than traditional motor-pump set. The mechanical efficiency improvement makes the overall efficiency of the axial piston EHP higher than motor-pump set. The influences to the loss by the oil gap length were analyzed, and the result indicates that the oil gap length can be further reduced.
Multi-type ribs of turbine blade modeling method fitting bowed-twist wall
Yang Jiong, Xi Ping, Hu Bifu, Zhang Baoyuan
2014, 40(6): 775-781. doi: 10.13700/j.bh.1001-5965.2013.0440
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Considering the geometric features of ribs in a bowed-twist cooling passage, a modeling method based on equidistant was presented. It generated rib tools, which was a tablet trimmed by equidistant surfaces of walls in intracavity of blade and pressure slide or suction slide, and then conducted modeling of ribbed channels. Furthermore, the principle of the modeling method was deeply analyzed, and two algorithms were developed, one recognized surfaces of walls in intracavity of blade automatically, the other matched two surfaces. The main parameters were determined as well. Meanwhile, a means based on sketch to parameterize ribbed channels was provided. Eventually, the parametric design module of ribbed channels was developed on unigraphics (UG), which achieved multiple ribbed channels modeling.
Rapid structure design and automated adjustment of civil aircraft fuselage
Chen Bai, Luo Mingqiang, Wu Zhe
2014, 40(6): 782-787. doi: 10.13700/j.bh.1001-5965.2013.0391
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To improve the quality and efficiency of civil aircraft design, it would be better to take structure design into account earlier, instead of beginning structure design in later preliminary design phase or detail design phase. A method to implement fuselage structure rapid design, modeling, and automated adjustment for civil aircraft was studied. The parametric modeling method of fuselage structure was represented， and a functionality of rapid fuselage structure design for civil aircraft, which can obtain the characteristics including mass, centre of gravity and inertia, was developed in an open aircraft conceptual/preliminary design system. In addition, the automatic adjustment of fuselage structure model and automatic update of mass property data were implemented, which contribute to multidisciplinary optimization work. An instance was presented to illustrate that this implementation method is feasible and effective.
Experiments of separated structure mechanical vapor compression system
Li Yulong, Wu Hong, Qiao Mai, Chen Jiang
2014, 40(6): 788-791. doi: 10.13700/j.bh.1001-5965.2013.0393
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Due to the disadvantages of the traditional mechanical vapor compression (MVC) system, a new MVC system which has the separated structure was presented. The new system was studied experimentally on a single effect system with a rated capacity of 1.5 m3/d. The experiment system consists of two sets of rotating evaporators, condenser and compressor. The performance of the system was evaluated at different compressor speeds and evaporating temperatures. It shows that the compressor and condenser inlet pressures fall gradually with the increases in compressor speed under a constant distillate production. However, the temperature difference increases with the increase in compressor speed, and the value of the highest temperature difference is stabilized at around 8.5℃. The different evaporating temperatures were obtained by the variation of the vacuum. Increasing the evaporating temperature enhances the production, and the performance is better with higher evaporating temperature.
Functional principal component regression for continuous spectra data
Huang Lele, Wang Huiwen, Zhu Jia
2014, 40(6): 792-796. doi: 10.13700/j.bh.1001-5965.2013.0409
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The method treating the smooth spectra as functional data was proposed and regression analysis was carried out based on functional principal components of spectra curves to obtain regression models without discretization. In modeling, the derivative curves of spectra can be introduced and bootstrap confidence intervals for functional coefficients were obtained. Using this method, the regression relationship between element concentration and X-ray spectra of glass samples was analyzed. It is shown that the functional regression based on principal components is more acceptable and has many advantages, because it complies with the characteristics of the data itself while attaining strong explanatory ability.
Experimental investigation on critical stall stage of counter-rotating fan at different speed ratio
Wang Zhuoqi, Lu Lipeng, Yuan Wei, Song Xizhen
2014, 40(6): 797-802. doi: 10.13700/j.bh.1001-5965.2013.0425
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Theoretical analysis on a low-speed counter-rotating fan shows that the critical stall stage is determined by two parameters, one is the critical stall mass flow coefficient of each rotor, the other is the real mass flow coefficient of the two rotors at stall point. An experiment was taken to confirm this supposition. The experiment was carried out on investigating the stall characteristic of a counter-rotating fan at different speed ratio. 36 cases was taken at 100%, 90%, 80%,70%,60%, 50% speed of each rotor. The result shows that the second rotor is the critical stall stage at design speed, and the critical stall stage could be changed by adjusting the speed ratio of the two rotors. It is also observed that the hysteresis stall loop appears when the first rotor is the critical stall stage, while it doesn't appears when the second rotor is the critical stall stage.
UAV lateral guidance law for tracking of maneuvering target
Wang Shulei, Wei Ruixuan, Guo Qing, Wei Wenjie
2014, 40(6): 803-809. doi: 10.13700/j.bh.1001-5965.2013.0453
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The existing lateral guidance law for standoff target tracking either converges slowly or has a large steady state error when tracking a maneuvering target. The reference point guidance (RPG) for path following problem was modified as lateral guidance law of unmanned aerial vehicle (UAV) for tracking a maneuvering target. The convergent process of relative distance between and target was modeled by two-dimensional nonlinear differential equations, and then the asymptotic stability of modified RPG was demonstrated. Simulation shows that, the modified RPG has smaller tracking error and integrated time absolute error (ITAE) compared to the methods of Lyapunov vector field guidance (LVFG) and model-based predictive control (MPC), thus the proposed guidance law makes an efficient compensation of the motion of maneuvering target, and has higher steady state accuracy and higher real-time performance.
Fast calculation method for helicopter reachable domain in forward flight
Zhuang Nanjian, Luo Zhangping, Ren Yiru, Xiang Jinwu
2014, 40(6): 810-814. doi: 10.13700/j.bh.1001-5965.2013.0632
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Helicopter reachable domain can be used to generate airspace security situation and improve the helicopter safety level in a low-altitude complex environment. In order to meet the demand on real-time performance and accuracy, a fast calculation method was proposed. The helicopter control zone was computed through energy method and the helicopter reachable domain mathematical model was established by combining kinematical equation with control zone. Based on optimal control theory, the boundary points of reachable domain were solved. The problem of constructing reachable domain in real time was transformed into the problem of calculating the boundary points. Two-dimensional and three-dimensional examples of AH-1G helicopter were analyzed and the results of the proposed algorithm were compared with differential inclusion method. The numerical results show that the control zone is time varying and should be computed on the basis of real-time flight status. Helicopter reachable domain in forward flight can be calculated in real time using the proposed algorithm and has high precision.
Shape optimization of supercavitating torpedo
Li Fuyuan, Zhang Yuwen, Teng Penghua, Zhang Yi
2014, 40(6): 815-818. doi: 10.13700/j.bh.1001-5965.2013.0444
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In order to optimize supercavitating torpedo shape and get the maximum vehicle volume under the same cavitation number, the formula for the best radius of the vehicle under the optimizing shape was deduced based on the empirical formula, by simplifying the cavity shape of disk cavitator and analyzing the vehicle shape in segmentation, considering the relationship of the cavity and the supercavitating torpedo. The volume of the optimized vehicle under a certain cavitation number was calculated, and compared with an existing vehicle model. It verified the effectiveness of the result. The results show that, shape optimization could increase the volume and the voyage, and improve the performance of the supercavitating torpedo. It provides a direction for increasing voyage of the supercavitating torpedo, and could be a reference for future shape design of supercavitating vehicle.
Thermal stress induced composite laminate delamination analysis and experiment verification
Ran Zhiguo, Yan Ying, Li Jianfeng, Cong Qiang, Chen Haifeng, Kuang Naihang
2014, 40(6): 819-823. doi: 10.13700/j.bh.1001-5965.2013.0485
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To solve thermal stress induced delamination in composite laminates that used in flying vehicles, experimental tests and numerical analysis were carried out. Bilinear controlled cohesive elements were adopted to simulate the delamination in laminates, quadratic failure criterion was used to predict the initiation of stiffness softening process, and power law criterion was applied to determine the delamination propagation under mix-mode fractures. The mechanical and thermal expansion properties of lamina applied in those numerical models were tested at high temperature (70℃), room temperature (23℃) and low temperature (-50℃) respectively. The delamination experiments were carried out by use of apparatus DIL-402C. Each composite laminate experienced a same temperature changes, and the maximum temperature difference was 120℃. After experiments, the laminates in given plies were found that delamination appeared in their mid-ply in both ends. Comparisons were made between experimental results and numerical analysis. Compared results show that the predicted delamination zone was well according with the experimental results, which would certify the rightness and reliability of this analysis method.
Variable-sampling-rate observer for speed estimation of servo motors with optical encoders
Zhang Jing, Wu Zhong, Huang Liya
2014, 40(6): 824-828. doi: 10.13700/j.bh.1001-5965.2013.0384
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Incremental encoders are heavily used as speed measurement sensors in servo motor systems. Speed estimation in these applications is frequently affected by system vibrations and quantization errors. To avoid this problem, a variable-sampling-rate observer was proposed. Instead of numerical differential operation used in the M/T method, the proposed procedure was based on numerical integration, so vibration noise could be effectively suppressed. In order to eliminate quantization errors, the observer adapts its sampling period with the generated encoder pulses in each calculation cycle. Varying sampling period changes the poles of the observer, which deteriorates the stability of the system, so a gain calculation procedure was given in order to maintain stability in wide speed range. Experimental result shows that the proposed observer can effectively reduce estimation error caused by quantization error and vibration, and obtain better precision while guaranteeing good dynamical performance.
Self-adaptive Newmark method of variable-mass beam dynamic system
Wang Yunan, Xing Yufeng
2014, 40(6): 829-833. doi: 10.13700/j.bh.1001-5965.2013.0400
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Variable-mass beam was used to model launch vehicle. Firstly the results of a spring-variable-mass ball system were compared with the analytical solutions. Then by using an example of a constant-mass beam, the parameters of the self-adaptive Newmark method were determined. At last the practical procedure of propellant decreasing and its effects on the transverse vibration were taken into account in a variable-mass beam. The self-adaptive Newmark method whose parameters depend on the inherent frequency of dynamic system, phase error and spectral radius of the method was employed to solve the dynamic responses of a variable-mass beam system, and the obtained results were compared with those of the analytical solutions by mode superposition method, average acceleration method (NMA) and Fox-Goodwin method (NMF). The comparison shows that the self-adaptive Newmark method is applicable to the variable-mass system, and it is more accurate than the methods used for comparison, especially the phase accuracy.
Compression performance of composite stiffened panel after stiffener repair
Zhao Chuang, Nie Hengchang, Guo Xia, Guan Zhidong
2014, 40(6): 834-838. doi: 10.13700/j.bh.1001-5965.2013.0431
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Subjected to compressive load, stiffener injury often causes serious failure of stiffened composite panels. In consideration of stiffener-skin debonding, delamination in web and damage to upper flange, corresponding repair programs were designed and necessary specimens were manufactured. In order to ensure a uniform compressive load during experiment, test fixture for composite stiffened panel was designed and fabricated, containing two slots to fix the stiffened panel and four guides to ensure the vertical loading direction. All the experiments that were taken using that fixture show the influences of different repair parts, different repair methods to the mechanical properties of stiffened panels are different. Finite element analysis shows that buckling mode, failure mode of stiffened panel and skin-stiffener glue injury are both influenced by repair programs.
Single event charge collection in CMOS device
Dong Gang, Feng Guoqiang, Chen Rui, Han Jianwei
2014, 40(6): 839-843. doi: 10.13700/j.bh.1001-5965.2013.0435
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Three dimensions technology computer aided design (3D TCAD) simulation was used to study single event transient (SET) in an invert with 90 nm bulk complementary metal oxide semiconductor (CMOS) technology. The charge transport and charge collection mechanism were analyzed in both positive channel-metal-oxide-semiconductor field-effect transistor (PMOSFET) and negative channel-metal-oxide-semiconductor field-effect transistor (NMOSFET) by numerical simulation. Results show that the radiation induced charge collection mechanism in an inverter device is different from single MOSFET due to coupling circuit effect, and the parasitic bipolar amplification component takes large proportion in charge collection of PMOSFET, but not in NMOSFET. The SET voltage pulse in PMOSFET is wider than NMOSFET and PMOSFET is more sensitive for SET in the submicron technology integrated circuit. The results provide the foundation for SET modeling in digital microcircuits and the model is used for SET simulation in large scale integrated circuits.
Design approach of nonlinear flight control law for fighter at high angle-of-attack based on mission-oriented flying qualities method
Long Jinwei, Pan Wenjun, Wang Lixin, Wang Zhigang
2014, 40(6): 844-848. doi: 10.13700/j.bh.1001-5965.2013.0436
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To solve the problem of maneuver control for fighters at high angle-of-attack (AOA), the model reference dynamic inversion (MRDI) control law was designed, based on the nonlinear dynamic inversion controllers utilizing angular rates as commands, ideal reference models representing the desired flying qualities and proportional-plus-integral compensators. Both the expected type of vehicle response and the control of maneuver at high AOA were approached by this method. The tuning of controller parameters, the rating of the airplane performance and the evaluation of close-loop system flying qualities were completed by simulation and the mission-oriented flying qualities (MOFQ) method which could be considered as a feasible assessment method for flying qualities at high angle-of-attack and it pointed out the demands for flying qualities created by special missions. The MRDI control law and the MOFQ method can be referenced by fighter control law design and flying qualities evaluation.
Experiment on surface integrity of side milling titanium TB6
Zhou Zitong, Chen Zhitong, Xiong Xiyao, Xu Yiping
2014, 40(6): 849-854. doi: 10.13700/j.bh.1001-5965.2013.0394
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The surface integrity (surface topography, surface roughness, work hardening) of TB6 after side milling was studied based on the minimum data set. The results show that it's the feed engagement (fz) that influences the surface topography most and high fz may cause scale on the milled surface. fz is the main reason that influences the roughness of feed direction. The surface roughness (Ra) raised from 0.283 μm to 0.964 μm with fz increased from 0.06 mm/z to 0.12 mm/z. The milling parameters (vc,fz,ae) have no apparent influence on the roughness perpendicular to the feed direction while the flank wear (VB) influences it a lot. With the VB raised from 0 to 0.025 mm, the roughness perpendicular to the feed direction increased from 0.22 μm to 0.686 μm. There is no apparent work hardening or surface degenerating layer appeared during the side milling process of TB6.
Improved battery state-of-charge estimation based on Kalman filter
Xu Ying, Shen Ying
2014, 40(6): 855-860. doi: 10.13700/j.bh.1001-5965.2013.0414
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Set in the research in the battery management system of electric vehicle, the state of charge, as well as the main factors to their nonlinear dynamic relationship, was illustrated and a second-order RC equivalent cell model was established based on the key technology of battery state of charge estimation. After taking the influence of temperature on the battery internal resistance into account, the state of charge of the battery was estimated with Kalman filter algorithm, the improved Ah counting method and the open-circuit voltage method, combined with the online thermal model parameters identification. MATLAB simulation shows that the average error was 2.46% compared with the conventional Kalman filter algorithm, which verifies the feasibility and reliability.

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