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2014 Vol. 40, No. 3

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Trajectory tracking control of space robot actuated by control moment gyroscopes
Jia Yinghong, Zhao Nan, Xu Shijie
2014, 40(3): 285-291. doi: 10.13700/j.bh.1001-5965.2013.0259
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A new design concept of space robotic system was proposed, as well as a trajectory tracking control approach. Unlike traditional manipulator arms, the space robot employs free ball joints as manipulator link connections. A group of control moment gyroscopes (CMGs), serving as torque actuators, was mounted on each link and the base. The modified Rodrigues parameters (MRPs) were employed to describe the attitude of the base and the links, and the equations of motion were derived by using Kane's equations. To accomplish trajectory tracking control of both the base position/attitude and the end effector position, a control law was designed using the inverse dynamics method. A steering law with null motion was adopted for each group of CMGs to achieve simultaneous desired torque output and singularity configuration avoidance. The simulation results based on a two-joint space robot system with pyramid-configuration CMGs demonstrate the effectiveness of the proposed control law and steering law, as well as the ball joint advantage in increasing the degrees of freedom of the end effector and decreasing the system dynamical coupling.
Analysis of adaptive random testing efficiency based on the experiment
Yin Yongfeng, Xiao Peng, Zhang Chi, Liu Bin
2014, 40(3): 292-297. doi: 10.13700/j.bh.1001-5965.2013.0265
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Adaptive random testing (ART) had been proposed as an enhancement of random testing with some algorithms, thus the ability of failure detection was improved. However, previous studies emphasised on the advantages of F-measure a lot but rarely considered the real testing environment. Three typical adaptive random testing algorithms and random testing algorithm were selected, and the impact of the compactness of failure regions, dimensions on the efficiency of ART was analyzed. Then fixed size candidate set (FSCS), which was the best ART algorithm, was compared with random testing in the non-numeric conditions. The results show that the range of application of ART is limited by many factors of input domain. And in real test, the enhancement of test efficiency is not obvious.
Bayesian networks and decision theory-based forward multi-step troubleshooting strategy
Yu Jinsong, Liu Hao, Wan Jiuqing, Zhang Ping
2014, 40(3): 298-303. doi: 10.13700/j.bh.1001-5965.2013.0264
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A forward multi-step troubleshooting strategy generation algorithm based on Bayesian networks and decision-theory was proposed for sequential diagnosis and maintenance problems. Troubleshooting knowledge under uncertainty was compactly represented by Bayesian network model and inference algorithm was independent on practical application. The correlation-ship among observations described in influence diagrams was explored to select reasonable forward multi-step observations and make troubleshooting decision in order to reduce blindness of repair. To verify the proposed method, the random troubleshooting strategy, decision theory strategy and ideal strategy were selected as comparison. Simulation results indicate that the proposed algorithm can significantly decrease the total troubleshooting costs by increasing the number of reasonable observer operation and reducing the numbers of maintenance focus and actual repair operation.
Thermal induced non-reciprocity of fiber coil in differential interference fiber optic gyroscope
Xu Hongjie, An Minghua, Xu Xiaobin, Teng Fei
2014, 40(3): 304-308. doi: 10.13700/j.bh.1001-5965.2013.0258
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Differential interference fiber optic gyroscope (DIFOG) is a new conception FOG. It can double the Sagnac signal and has the advantages of small size and high signal-to-noise ratio. In order to improve the temperature performance of DIFOG, the thermal-induced nonreciprocal error model of fiber coil was built based on its special light path. Then the effect of the position of 90° splicing point on thermal induced non-reciprocity error was analyzed and simulated. The results show the thermal induced non-reciprocity error is decreased significantly when the 90° splicing point at the midpoint of fiber coil. The corresponding thermal excitations experiments were also carried out. The experimental results are in agreement with theoretical calculation, and show that by modifying the 90° splicing point to the middle of fiber coil the thermal induced non-reciprocity error is reduced by a factor of~400.
Air-ground coordination traffic status perception and emergency commanding system construction
Zhang Yuxiao, Wang Yunpeng, Tang Wenzhong, Li Honggang
2014, 40(3): 309-313. doi: 10.13700/j.bh.1001-5965.2013.0675
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The time and place of traffic incident is unpredictable. It will seriously disturb the normal traffic if not dealt with in timely manner. The space-based traffic status perception and emergency commanding system was built, and its contribution principles were proposed. The system architecture was researched, which was divided into 4 layers, that is information acquisition layer, network layer, safety management layer and emergency command layer. Information acquisition layer mainly obtains the traffic information through a variety of ways such as ground or space-based foundation. Network transmission layer handles the store and forward of all types network communication packet. Safety management layer ensures the safety of system data and transport. Emergency commanding layer realizes unification receiving alarm, dealing alarm decision and coordinate command. The space-based information extraction about road contour feature and vector electronic map, and the matching between aerial images and electronic map were all realized. It laid a good foundation for identifying queuing length and vehicle density caused by an emergency situation.
Forecasting of the China Sea ditching probability using WW3 wave model
Zheng Chongwei, Pan Jing, Huang Gang
2014, 40(3): 314-320. doi: 10.13700/j.bh.1001-5965.2013.0247
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The ocean wave has a significant influence on the ditching probability. Comprehensively considering the standard deviation of the flying height of the sea-skimming aircraft, standard deviation of the ocean wave, the numerical forecasting of the ditching probability was developed, by using WW3 (WAVEWATCH-Ⅲ) wave model and T639 forecasting wind field data. The results provide a scientific reference for the route planning of sea-skimming aircraft. The ditching probabilities of 5 meters, 10 meters and 15 meters above the sea surface were calculated and contrasted. Results show that the WW3 wave model can forecast the China Sea wave field and ditching probability properly, with T639 forecasting wind field data as the driving field. Under the influence of the cold air, the China Sea ditching probability increases significantly. The ocean wave would cause a great threat to the security of sea-skimming aircraft when the flying height is below 10 meters.
Integral sliding mode nonlinear controller of electrical-hydraulic flight simulator based on neural network
Han Songshan, Jiao Zongxia, Wang Chengwen, Shi Yan
2014, 40(3): 321-326. doi: 10.13700/j.bh.1001-5965.2013.0688
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For the feature that high-accuracy electrical-hydraulic flight simulator (EHFS) is highly nonlinear and contains parametric uncertainties and uncertain nonlinearities, an integral sliding mode nonlinear robust controller based on radial basis function (RBF) neural network was proposed. The adaptive RBF neural network was adopted to eliminate the effect of parametric uncertainties and uncertain nonlinearities. By reducing the gain of switching function in sliding mode controller, chattering phenomenon could be minimized significantly. The steady state error from external disturbances could be eliminated by integral sliding control law, which was divided into an equivalent control law and a hitting control law. Equivalent control law was designed to keep the system sliding along the sliding surface. Hitting control law was applied to drive the representation point of the state space onto the sliding surface. The globally asymptotic stability of developed controller was proven via Lyapunov analysis. Comparative experimental results demonstrate the effectiveness of the proposed algorithm.
Aeroelastic analysis method for wind turbine blade based on large deformation beam model
Zhang Xintan, Yang Chao, Wu Zhigang
2014, 40(3): 327-332. doi: 10.13700/j.bh.1001-5965.2013.0596
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Large amplitude aeroelastic response problem of wind turbine blade was investigated. Nonlinear Euler beam model, dynamic inflow and dynamic stall model were adopted in aeroelastic modeling. Newton-Raphson iteration was used to solve the nonlinear aeroelastic equations. Newton-downhill method and homotopy continuation algorithm were used respectively to improve convergence, and the result shows that the homotopy continuation is more effective. Two typical wind turbines were analyzed in rated conditions and in extreme wind conditions. The system stability boundary was defined according to the amplitude of blade bending moment, and the relationship between the critical wind speed and azimuth angle of the inflow was researched. The results indicate that the wind turbine blades suffer excessive bending moment in some extreme wind conditions, and the aeroelastic stability boundary of the blade would be reached in some operation mode.
Analysis and optimization of envelope material of high-altitude airships
Yang Yongqiang, Ma Yunpeng, Wu Zhe
2014, 40(3): 333-337. doi: 10.13700/j.bh.1001-5965.2013.0390
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The envelope material of high-altitude airship was analyzed and optimized. Coupling relationship between the thermal properties of the functional coating layer and mechanical properties of the load-carrying layer was researched. Analysis and optimization of the envelope material based on a special condition were carried out. An optimization scheme based on the Vectran flat knitting load-carrying layer made of flat knitting Vectran and functional coating layer made of aluminized-PET was obtained. High altitude flight test was used to validate the feasible of the optimization scheme. Results show that the optimization method is applicable to get feasible optimization schemes, which will provide technical support to the super-pressure long endurance of high-altitude airship.
Novel non-uniform multi-tone system based on Ramanujan sums
Zhou Lina, Wang Zulin, Shang Jiadong, Yang Lan
2014, 40(3): 338-343. doi: 10.13700/j.bh.1001-5965.2013.0446
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In the high speed mobile communication systems, the channel is usually a random or jitter of uniform frequency channel because of the fluctuations in speed of moving vehicles and multi-path effect. This fact leads to a study of non-uniform spectrum system. A novel non-uniform multi-tone system based on Ramanujan sums was proposed. First it was proved that the transform pair based on Ramanujan sums can be perfectly reconstructed at some circumstance. Then an efficient realization structure to build a multi-tone system named as Ramanujan Fourier multi-tone system (RFMT) was proposed and simulated in additive white Gaussian noise (AWGN) and multi-path channels. With the help of non-uniform spectrum and diversity character, RFMT can protect different data in different sub-carriers and achieve a 4 dB lower Eb/N0 than orthogonal frequency division multiplexing (OFDM) in 3-path channel using zero-forcing equalization with bit error rate (BER) 10-5.
Fast design method of moon-to-earth transfer trajectory
Zheng Aiwu, Zhou Jianping, Liu Yong
2014, 40(3): 344-349. doi: 10.13700/j.bh.1001-5965.2013.0241
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Design of moon-to-earth transfer trajectory is generally divided into two phases, preliminary orbit design and precise orbit design. Among them, the accuracy of preliminary design is the key to the convergence of precise design. A fast design method of moon-to-earth transfer trajectory based on Lambert algorithm was proposed. The time when the probe piercing the lunar sphere of influence, the position and the velocity at that moment were used as intermediate variables. The moon-to-earth transfer trajectory was divided into two segments to calculate separately, geocentric segment and lunar segment. In the rapid calculation of geocentric segment, the geocentric flight from the point where the probe piercing the lunar sphere of influence to the specified reentry point was simplified as a Lambert problem, which was solved by Newton iterative method. It greatly improved the computational efficiency by avoiding a large number of hypergeometric functions or series calculations. In the rapid calculation of lunar segment, a new method was presented to obtain the moon centered hyperbolic orbit elements according to the velocity vector at the sphere of influence, the inclination and perilune altitude of the lunar parking orbit. Making the position and velocity vectors of the two segments continuous at the lunar sphere of influence, a complete moon-to-earth transfer trajectory meeting the constraints at both ends was obtained by iterative calculation. The accuracy of the fast design method is relatively high besides the fast calculation. The results were also used as inputs of the precise orbit design.
Decoding for LDPC codes with enhanced residual belief-propagation
Zhao Ming, Zhang Xiaolin
2014, 40(3): 350-354. doi: 10.13700/j.bh.1001-5965.2013.0254
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The performance improvements of residual belief-propagation (RBP) and node-wise RBP (NWRBP) decoding algorithms for low-density parity-check (LDPC) codes are very limited while at cost of high computational complexity. The enhanced RBP (ERBP) decoding algorithm was proposed, which updates only one message and then sets the residuals of all messages in the row of the updated message to 0 in one sub-iteration, thus the ERBP can utilize the messages in different check equations in each sub-iteration to increase the iteration convergence rate. Different LDPC codes were used to test the performance of the proposed algorithm. The simulation results show that the proposed algorithm, when compared with other algorithms, lowers frame error ratio (FER) and speeds up the iterative convergence.
Fault tolerant control based on control allocation for morphing aircraft model
Jiang Weilai, Dong Chaoyang, Wang Tong, Wang Qing
2014, 40(3): 355-359. doi: 10.13700/j.bh.1001-5965.2013.0255
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To cope with the fault tolerant control problem of innovative control effectors (ICE) morphing aircraft with actuator fault, employing control allocation method and theory of integer programming, a fault tolerant control scheme based on control allocation was proposed. Firstly, virtual control law was designed to assure that the ICE aircraft can track a desired reference model. Afterwards, the probabilistic fault and saturation constraint of actuators were translated into decision variables constraint of integer programming by the reconfiguration of distributed shape-change effector arrays. In this way, the problem of control allocation was considered as a class of integer programming problem with probabilistic decision variables. To ensure availability and convergence, optimized genetic algorithm was used to solve the problem. Simulation results shows that ICE aircraft with actuator fault also has good tracking performance.
Simulation of wind field over complex terrain based on elevation data
Tang Chu, Hong Guanxin
2014, 40(3): 360-364. doi: 10.13700/j.bh.1001-5965.2013.0257
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A numerical simulation method for the wind field over complex terrain was developed. The complex terrain was represented by a surface, which was established by the surface spline method based on the contour line of the map. Then it was divided into panels containing vortex ring singularities. The singularity distribution was solved by combining with the potential flow theory and the boundary condition of terrain surface. Finally, the wind field was simulated by linear superposition of the uniform stream and the induced velocity of vortex rings. A numerical example was studied, and the result was also compared with the one obtained by existing method. It indicates that the method proposed could describe the terrain much more accurately and provide a reasonable result of wind field distribution, but has a simple and efficient procedure, which is suitable for the engineering use in flight dynamics.
Novel camera observing reliability model
Sun Qian, Xu Dong
2014, 40(3): 365-369. doi: 10.13700/j.bh.1001-5965.2013.0211
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For camera observing ability was constrained by its view angle and scene structure, a novel camera observing reliability model was studied based on people's eye sensing ability model. According to Johnson's rule, observing distance, view angle and target size were considered synthetically in this model, and this model was more consistent with the true circumstance, as it could determine whether a target was in its field of view, as well as whether the target was observed from a better view. Multi-camera observing reliability and target capture rate were defined on this basis, and an optimized camera deployment algorithm was investigated. Simulation results show that more detailed scene information can be obtained by this method. The scene coverage rate and target capture rate were greatly improved.
Simulation analysis on air-to-air missile allowable launch envelope about cooperative air combat of multi-fighter formation
Diao Xinghua, Fang Yangwang, Wu Youli, Fu Xiaofei
2014, 40(3): 370-376. doi: 10.13700/j.bh.1001-5965.2013.0237
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A method for calculating allowable launch envelope of air-to-air missile in multi-aircraft cooperative air warfare was researched. The mechanism of launch envelope of air-to-air missile was analyzed of single-aircraft in the actual case. Considering the mode of cooperative launch/guidance of air-to-air missile, the definition of cooperative launch envelope was conclude. Based on the target, missile and aircraft movement model and the constraints of cooperative launch envelope, the golden section-probability searching method was proposed to calculate the cooperative launch envelope, and some simulations were made to work out the parameters' affection in case of two fighters cooperatively attacking. Simulation results show that multi-aircraft cooperative guidance can enlarge the allowable launch envelope of missile obviously and the cooperative launch envelope was affected by the parameters of the guider and the missile.
Hover-stage lunar lander autonomous relatively navigation
Su Qinghua, Zhao Yan, Yang Kui, Zhang Shaochen
2014, 40(3): 377-382. doi: 10.13700/j.bh.1001-5965.2013.0244
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The lunar lander landing phase navigation information analysis is a key to achieve the safety soft landing on lunar surface. According to requirements for the hover-stage navigation, the lunar lander carrying equipment and its access to the characteristics of the lunar surface, laser rangefinder and optical navigation camera optical were used in autonomous relative navigation. A coordinate system relative navigation was created. According to the relationship between the various coordinate systems, the transformation matrix and navigation information was determined, the position and attitude of the lander relative lunar landing point was estimated. Finally, the method was verified by simulation experiments. Results show that this method can calculate relative position, posture fast and accurately. The method is valuable for further steps of moon exploration projects, and can be used as soft-landing close relative navigation for Mars and other asteroids exploration.
Automatic calibration of output signals from resolvers
Zhang Jian, Wu Zhong
2014, 40(3): 383-388. doi: 10.13700/j.bh.1001-5965.2013.0246
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The outputs of resolvers are amplitude modulated signals, one with the sine and the other with the cosine of angular position. In order to obtain the rotor angular position and velocity information, detection and demodulation are required. However, detection results often contain dc offsets, amplitude deviation and non-orthogonal phase shift. To enhance demodulation accuracy, a calibration procedure is necessary before demodulation. An offline automatic calibration method was introduced to meet this need. A state observer was introduced to estimate the amplitude and dc offsets of the detected signals. To estimate the phase shift, a two variable quadratic goal function was constructed, which can be resolved by gradient estimator. Compared with the method that using only gradient estimator, the multiple-roots problem was resolved. The validity of the calibration method was proved by experiments. The proposed method doesn't need complicated parameter selection, and converges to single root with high accuracy.
Comparison analysis between two continuum breakdown parameters applied in coupled NS-DSMC method
Tang Zhenyu, Cai Guobiao
2014, 40(3): 389-393. doi: 10.13700/j.bh.1001-5965.2013.0252
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Navier Stokes-direct simulation Monte Carlo (NS-DSMC) coupled method is a principal method for the computation of continuum-rarefied transitional gas flows. How to locate the interface between continuum and rarefied domains is one of the key aspects in using this method, which is generally achieved by applying a continuum breakdown parameter. To choose the continuum breakdown parameter more reasonably, theoretical analysis and comparisons were carried out for two major continuum breakdown parameters: KnQ and B, which show that they have similar mathematical forms to a certain extent, although they are established from different basis. Numerical test was conducted by using an over-cylinder flow problem which also indicates the relationship between them. KnQ and B parameters have few differences when applied in NS-DSMC coupled method, except that KnQ parameter has a widely used threshold value of 0.05, but the threshold value of B parameter will vary for different flows.
Embedded software testing technology based on all-digital simulation
Liu Hui, Jin Maozhong
2014, 40(3): 394-400. doi: 10.13700/j.bh.1001-5965.2013.0260
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For the test of real-time embedded system, the integrated all-digital simulation technology was proposed, which can resolve two functional problems in current software testing environment: ①Taking the simulation clock as the time reference, the synchronization due to setting break points was resolved; ② the "dynamic stub" approach was designed to drive the unit-testing for the embedded program that may not be complete, i.e. lack of supporting functions, like library. Furthermore, by significantly reducing judgments in each clock cycle using the lossless compression, the efficiency problem of the simulation platform was resolved, which promotes the practicability of this technology. The integrated simulation technology supports the whole test process from unit test to the integrated test, which strengthens ability of finding software bugs in real-time signal exception processing, improves the efficiency of system-level software testing, and achieves the reuse of test scripts. The platform has been applied to the testing of flight control software.
Design of nonlinear optimal controller for multi-missile formation
Zhang Lei, Fang Yangwang, Diao Xinghua, Hu Jie
2014, 40(3): 401-406. doi: 10.13700/j.bh.1001-5965.2013.0268
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To solve the formation control problem of multi-missile formation, the optimal control theory of affine nonlinear system was adopted to design the formation controller of missiles based on leader-follower approach. Firstly, precise linearization based on differential geometry theory was used to linearize the nonlinear motion model of the missile. Secondly, according to the relative motion model of leader and follower, the desired follower track including the states of leader and the desired formation relative distances was given, and system model with follower track errors was formulated. Finally, riccati matrix differential equation solution based on steady state solution was introduced to solve the optimal control problem and a three-dimensional nonlinear optimal formation controller was designed. Simulation results show that the controller is robust to leader maneuver, and is capable of forming and keeping formation figuration rapidly, stably and exactly.
Fault detection and time domain of flight networked control system
Ma Aojia, Dong Chaoyang, Wang Qing
2014, 40(3): 407-412. doi: 10.13700/j.bh.1001-5965.2013.0279
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The problem of fault detection was studied for flight networked control system with Markov delay and packet dropout. The networked control system with those problems was modeled as discrete Markov jump system. Based on this model, the residual generator was constructed as the observer and the problem of fault detection was transformed to the problem of H∞ filtering problem. The solvable condition of the fault detection filter and further the solution were derived by using linear matrix inequality techniques. To improve the performance of the fault detection system and enhance the sensitivity to the fault, a time domain optimization approach and it's solution were proposed to deal with the residual evaluation function. A numerical example was provided to illustrate the effectiveness of the proposed approach.
Spares optimization under the influence of false alarm
Bian Jiehui, Guo Linhan, Kang Rui, Yang Yi
2014, 40(3): 413-416. doi: 10.13700/j.bh.1001-5965.2013.0238
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When false alarm exists, spares would be misdiagnosed as failed ones and requirements for new spares would be sent to the repair site, the demand rate for spares will be overestimated. So it's necessary to introduce false alarm rate to make it more accurate. The formula was proved that when false alarm rate follows exponential distribution, the failed spares considering false alarm rate follows Poisson distribution. According to the multi-echelon inventory for repair spares control theory, the functional relation between demand rate considering false alarm rate and expected backorder (EBO) was founded. In the case of spares optimization, the objective function was convexly analyzed, and the convex algorithm facing system false alarm was set up with expected backorder being as performance measure, so that the selected inventory can improve the system efficient under the situation of false alarm being. Besides, the application case of airplanes was given out with the optimum spares configuration for comparison.
Influence of limiters on numerical simulation of heating distributions for hypersonic bodies
Yang Jianlong, Liu Meng
2014, 40(3): 417-421. doi: 10.13700/j.bh.1001-5965.2013.0253
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The Roe's flux difference splitting (FDS) scheme was combined with min mod, van Leer and Osher-C limiters to simulate hypersonic flow fields around hypersonic bodies. The different effects of the three limiters on the simulation results of hypersonic bodies' aerodynamics and aerothermodynamics were researched, and their effects on the simulation of heating rates were compared and analyzed. From the results, it can draw the following conclusions: the choice of limiters has a very important effect on numerical simulation results, and it will influence the simulation results of aerothermodynamics more than the ones of aerodynamics. The min mod limiter, working together with Roe's FDS scheme can obtain better heating rates on hypersonic bodies than the other two limiters no matter for simple or complex aerodynamic shapes. Therefore, the min mod limiter can provide reliable results for the thermal protection designs.
Preparations of fluorine-containing solid hydrophobic agent and properties of hydrophobic film
Feng Li, Li Weiping, Liu Huicong, Zhu Liqun
2014, 40(3): 422-426. doi: 10.13700/j.bh.1001-5965.2013.0245
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A solid hydrophobic agent with fluorine was mainly prepared by organosiloxane and hydroxyl fluorosilicone oil. After dissolved in ethanol in different concentration, the as-prepared solid hydrophobic agents were coated on the surface of A3 steels to obtain transparent hydrophobic film with thickness of less than 1μm. And the hydrophobicity and corrosion resistance of the hydrophobic film were investigated. Results show that the hydrophobicity of the water-repellent film, as well as hydrophobic stability and corrosion resistance, are affected by the concentration of the hydrophobic agent. The addition of fluoride can obviously improve the contact angle of the hydrophobic film and enhance the corrosion resistance.

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