Table of Content

30 June 2017, Volume 51 Issue 6 Previous Issue    Next Issue

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A Fast Satellite Selection Algorithm for  BDS/GPS Dual Navigation System GONG Caihe,MAO Xuchu,LI Shaoyuan 2017, 51 (6):  641-646.  Abstract ( 754 )   Save  With the development of Global Navigation Satellite System, the number of visible satellites is gradually increased. Satellite selection is then proposed in order to achieve a balance between computation and positioning accuracy. This paper presents a fast satellite selection algorithm by using BDS/GPS double system. This algorithm is based on optimum constellation configuration and underlying center method, the satellite selection is determined based on the characteristics of multisystem, and the algorithm is validated. The experimental results show that the algorithm can reduce calculation cost under the guarantee of positioning accuracy. References | Related Articles | Metrics

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The Interference Analysis of the FullDuplex TwoWay Relaying with  Large Antenna Arrays QIU Mengting,ZHAO Pu,YU Hui 2017, 51 (6):  647-656.  doi: 10.16183/j.cnki.jsjtu.2017.06.002 Abstract ( 747 )   Save   In recent years, the fullduplex twoway relaying system with Massive multiple input multiple output (MIMO) has attracted significant interest because of its performance gain on spectral efficiency and energy efficiency, but it has the problems of residual loop interference (RLI) and pilot contamination. Therefore, this paper considers a Kpair fullduplex twoway relay system, and each user equips single antenna. The relay uses maximumratio combining/maximumratio transmission (MRC/MRT) beamforming to process the signals, and it estimates the channels by only K pilot symbols for 2K users. By theoretical analysis, it is concluded that when very large receive and transmit antenna arrays are used, the RLI due to full duplex and the pilot contamination can be simultaneously cancelled, also the interpair interference and noise vanish. Simulations verify the theoretical results, and show that the energy efficiency and spectral efficiency can increase with the antenna number. Moreover, it is shown that the fullduplex twoway relaying outperforms the halfduplex twoway relaying and the fullduplex oneway relaying in the spectral efficiency when the number of relay receiving/transmitting antenna is up to 160. Therefore, the fullduplex twoway relaying with large antenna arrays has higher communication efficiency than traditional relaying systems. References | Related Articles | Metrics

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Design of Boost DCDC Converter with  Frequency Hopping at Light Load HU Jiajun,CHEN Houpeng,WANG Qian,LI Xi,MIAO Jie,LEI Yu,SONG Zhitang 2017, 51 (6):  658-664.  Abstract ( 568 )   Save  This paper analyzes the high power conversion efficiency limit at full load range of traditional boost DCDC converter. Based on the analysis, light load detector and adaptive frequency hopping mechanism are put forward. The proposed technique doesn’t need additional pad and device while the load condition can be accurately detected in the Discontinuous Conduction Mode (DCM)  of inductor current. The proposed boost DCDC converter is simulated in the CZ6H 0.35μm standard CMOS process, and results show that the proposed converter can adaptively select control frequency according to the load detector. At the load condition of 1 mA, power conversion efficiency can be up to 82%. System feedback loop can keep well stable within a wide range of load variation. For a load step of 1.5μA/20μs, the circuit has a maximum undershoot of 300mV and a maximum overshoot of 200mV. The recovery time is only 80μs and 60μs respectively，and the layout area is about 1.26mm2. References | Related Articles | Metrics

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Recognition Method for Gas Pores on XRay Image of Lap Joints Based on the Improved Sobel Algorithm JIANG Huajuna,CAI Yana,b,LI Chaohaoa,LI Fanga,b,HUA Xueminga,b 2017, 51 (6):  665-671.  Abstract ( 657 )   Save   An adaptive recognition method for inner pores of welded joint was proposed based on Xray image. The Xray image templates were designed and established through local dynamic threshold method. The weld edge was extracted and marked from complicated background through improved Sobel algorithm. The gray gradients of original image in both x and y directions were investigated in the marked zone. The recognition capability for small pores and adhesive pores was enhanced. Application results showed that the proposed method had satisfied recognition capability, detection precision and response speed. It could effectively solve the problems of manual detection and provide platform for data storage and query. References | Related Articles | Metrics

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Model Identification Based on Subspace Model Identification of  Superheated Steam System in UltraSupercritical CoalFired Power Unit MENG Qingyang1,YAN Weiwu1,HU Yong1,CHENG Jianlin1,CHEN Shihe2,ZHANG Xi2 2017, 51 (6):  672-678.  Abstract ( 452 )   Save   The superheated steam system ultrasupercritical unit is a multiinput and multioutput system. In this paper, a datadriven subspace approach is introduced for the model identification of the superheated steam system. In the approach, the unit step response coefficients are drawn directly, then the loworder transfer function of the system is obtained by leastsquare regression. Finally, closed loop identification based on datadriven subspace approach is applied to the superheated steam system of ultrasupercritical coalfired power unit. Real application shows that proposed identification strategy has a small computational cost and can meet the accuracy requirements in industrial sites. References | Related Articles | Metrics

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Soft Faults Diagnosis of Track Circuit with Tolerance Based on  NodeVoltage Increments JIA Lei,DONG Wei，SUN Xinya，JI Yindong，CHEN Hua 2017, 51 (6):  679-685.  Abstract ( 527 )   Save  The fault diagnosis of track circuit is very important for ensuring the normal operation and safety of trains. However, the existing researches on fault diagnosis of track circuit mostly focus on the hard faults diagnosis. And there is a lack of researches on the fault diagnosis methods of track circuit with tolerance. The existence of tolerance makes it difficult to apply related theory of fault diagnosis methods to actual engineering. Aiming at these problems, this paper researches the fault diagnosis of track circuit with tolerance and proposes methods to eliminate the effect of tolerance, based on sensitivity analysis. This paper also proposes the soft faults diagnosis dictionary methods of track circuit with tolerance, based on nodevoltage increments. The simulation experiment shows that the proposed methods can effectively diagnose the soft faults of track circuit with tolerance. References | Related Articles | Metrics

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A New Method for Transition Identification by  Using Dynamic Information HE Yuchen,GE Zhiqiang,SONG Zhihuan 2017, 51 (6):  686-692.  Abstract ( 710 )   Save  An identification method is proposed for transitional processes by using  dynamic information. A definition for the transitional process is presented here to make a brief description of the characteristics of transition. Because of the existence of dynamic behavior in industrial processes, a dynamic mutual information (DMI) method is proposed in this paper. The differences in statistical characteristics between transition and stable modes can then be well revealed through the DMI algorithm. Extensive tests are carried out both on a numerical example and Tennessee Eastman (TE) benchmark process to validate the effectiveness of the proposed method. The simulation results show the superiority of the proposed method in transition identification and fault detection. References | Related Articles | Metrics

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Global Sliding Mode Control Approach for the Steering System of  the WaterJet Propulsion Device GONG Zhenghua1，TIAN Zhen2，XIONG Wen1，LI Junzhou1,LI Gangqiang1，YUAN Jingqi2 2017, 51 (6):  693-697.  Abstract ( 619 )   Save   Waterjet propulsion is an advanced propulsion technique for high speed ships. The robustness of its steering control system is an essential demand due to various disturbances. In this contribution, the mechanism transfer function model of the waterjet steering propulsion system is established first. Then, model based disturbance observer is designed and a global sliding mode controller is developed. Furthermore, the existence of global sliding mode and the asymptotically stability of the closedloop system are proved. Simulation results are presented to demonstrate the high precision of the disturbance observer, good tracking performances and strong robustness of the control strategy. References | Related Articles | Metrics

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Gainscheduling Control Based on  Linear Parameter Varying Model of Buck Converters LUO Xu1，ZHANG Gansheng2，XIE Wei2 2017, 51 (6):  698-703.  Abstract ( 670 )   Save  The output of switching converters can be easily influenced by the load and the line voltage. In this paper, a gain scheduling control based on a linear parameter varying (LPV) model of Buck converters is proposed to avoid this situation. Firstly, based on the small signal model of Buck converters, the LPV model with the load and the line voltage used as varying parameters is established by convex decomposing technique. Then, an LPV controller is designed with a structure of convex polytope using linear matrix inequality (LMI) technique. A system with this controller can have H∞ performances and all the closedloop system poles are located in a specific area. Finally, the simulation results show that the system with LPV controller has better performances than those with robust state feedback controllers. References | Related Articles | Metrics

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PerferredLearningBased Differential Evolution Algorithm LIU Hao，DING Jinliang，YANG Cui’e，CHAI Tianyou 2017, 51 (6):  704-708.  Abstract ( 798 )   Save   Traditional differential evolution (DE) algorithm only abstracts information of random and the best individual. Randomness may result in a low searching efficiency, and even cannot find the best solution. A perferredlearningbased DE algorithm is proposed to solve this tough problem. The algorithm selectively uses the wellbehaved individual’s information and overcomes the blindness in the evolving process to enhance the searching ability. After different kind benchmark functions are investigated, the results reveal that the number of iterations can be clearly reduced and the calculation efficiency can be improved. References | Related Articles | Metrics

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Modular Position/Force Control for  Environmental Constrained Reconfigurable Manipulator LI Yuanchun1,SONG Yang2,ZHAO Bo1,3 2017, 51 (6):  709-714.  Abstract ( 632 )   Save   This paper proposed an adaptive neural network modular position/force control method for environmental constrained reconfigurable manipulator. Mapping the endpoint force of the reconfigurable manipulator to each joint module, describe the entire dynamic model by a set of interconnected subsystems by coupling torques, and the position and contact force of the endpoint should be obtained by controlling the angle and torque of each subsystem. By virtue of the neural networks, the nonlinear and interconnected items are estimated, and the weights of these neural networks can be adaptively updated on line, meanwhile, the estimated errors are removed by a sliding mode control item, and the stabiltiy of the closedloop system should be granteed. Finally, the numerical simulation on two different 2DOF reconfigurable manipulators shows the effectiveness of the proposed method without changing control parameters. References | Related Articles | Metrics

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Coverage Enhancing for Underwater Acoustic Sensor Networks Based on  Virtual Force and Fruit Fly Optimization Algorithm ZHANG Ying,QIAO Yunlong*,ZHANG Haiyang 2017, 51 (6):  715-721.  Abstract ( 528 )   Save  This paper proposes the virtual force and fruit fly optimization (VFFO) algorithm which consists of the improved virtual force and fruit fly optimization methods. The algorithm firstly optimizes the initial deployment by virtual force to get a better initial deployment status, then the improved fruit fly optimization algorithm is used to redeploy the sensor networks. Moreover, the energy consumption of the deployment is analysed. The simulation results show that the proposed algorithm can achieve a higher effective coverage rate with the same energy consumption. References | Related Articles | Metrics

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A Soft Sensor Modeling Method Based on  SelfAdaptive Fuzzy Gauss Kernel Clustering XIA Yuan,YANG Huizhong 2017, 51 (6):  722-726.  Abstract ( 612 )   Save  It is difficult for a single model to express the complicated production process, and it often results in low accuracy of prediction and poor performance of generalization. This paper presents a multimodel fusion method based on probability weight and selfadaptive fuzzy Gauss kernel clustering. The method determines cluster centers according to dispersion of the samples in a high dimensional space. The weight of every submodel is given by Bayesian posterior method. The method can overcome the limitation of singlemodel forecast and improve traditional multimodel fusion methods for obtaining higher prediction accuracy. References | Related Articles | Metrics

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Dynamic MultiTarget Recognition Based on Machine Vision XUE Mengxia,LIU Shirong,WANG Jian 2017, 51 (6):  727-733.  Abstract ( 1130 )   Save  This paper proposes a realtime dynamic multitarget recognition method based on machine vision. The method first segments the moving targets according to the pixel change between the front and rear frames, then extracts the features of the segmented moving targets and sample images using Gabor filter to obtain the eigenvector, and finally uses Fisher discriminant criterion for classification and recognition so as to automatically lable the classification and recognition results onto the output images. The images labeled with the recognition results are to be outputted continuously, and hence the output videos which have been recognized can be obtained. The experimental results show that in the circumstance of multiple targets, the proposed dynamic target recognition method integrating Gabor feature and interframe difference can accurately detect the dynamic target area, and realize classification, recognition and labeling. References | Related Articles | Metrics

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An Optimal Fuel Guidance Law for Lunar SoftLanding Based on  ThreeDimensional Dynamic Model XIAO Yao,RUAN Xiaogang,WEI Ruoyan 2017, 51 (6):  734-740.  Abstract ( 674 )   Save   Optimal fuel consumption is required in the process of lunar softlanding. An optimal fuel guidance law is designed with the method of variational calculus. The problem is converted into the terminal timefree twopoint boundary value problem (TPBVP) based on variational calculus. Then a timescale method is used to convert the terminal timefree TPBVP into terminal timefixed TPBVP. Finally, an initial adjoint variables guess approach is introduced to assure the convergence of the numerical iteration method for solving TPBVP. The exact terminal time and initial value of adjoint variables are calculated by numerical method, as well as the optimal fuel guidance law and 3D optimal trajectory. The simulation results show that the proposed method is valid and achieve the goal of optimal fuel guidance. References | Related Articles | Metrics

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ARMBased Simulation Test System for Train Control Algorithms HOU Xiaoweia,TANG Zhaoquanb,SUN Xubin，CAI Hu,ZHANG Mengyanga,DONG Haironga 2017, 51 (6):  741-747.  Abstract ( 671 )   Save  Train control system is a crucial system for the train to operate efficiently and safely. Automatic train operation (ATO) system can make realtime speed regulating of the train according to the target speed profile. The basic units, including ATO, and the functions of the vihicle onboard control system (VOBC) are introduced. Based on the analysis of ATO, we design a hardwareintheloop simulation test system for train control algorithms. The simulation test system consists of the hardware and software, which communicate through universal asynchronous receiver/transmitter (UART). Finally, we propose a train control algorithm based on Slidingmode state obsever, which is tested on the simulation test system. References | Related Articles | Metrics

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Mechanical Seal Performance of Rough Surface Influenced by Tilt YANG Xiao,PENG Xudong,MENG Xiangkai,WANG Yuming 2017, 51 (6):  748-755.  Abstract ( 660 )   Save  According to the actual operating conditions of mechanical seal used in aviation pumps, a theoretical model of hydrodynamic and mixed lubrication conditions was developed for mechanical seal with rough and tilted surfaces. The model considered elasticplastic contact between rough surfaces, and the JakobssonFlobergOlsson (JFO) cavitation boundary condition of mass conservation in lubrication film. Finite element method was used to solve the Patir and Cheng average Reynolds equation, and the fluid film pressure distribution between seal surfaces was obtained. The influence of the nondimensional tilt angle on the seal performance was analyzed under different values of sealed pressure, central film thickness and rotational speed. A performance comparison between rough and smooth surfaces was conducted with a mechanical seal. The results showed that with increasing tilt angle, the load carrying capacity and the leakage rate increased, the friction force decreased firstly and then increased. The mechanical seal with rough surfaces had better performance than that with smooth surfaces when one of seal surfaces had a small tilt angle. References | Related Articles | Metrics

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Precise Integration Method for Solving FluidSolid Coupling Problems WU Zeyu1,2,WANG Dongwei3,WANG Zhihao2,SONG Li1,FEI Xiaoxia4 2017, 51 (6):  756-760.  Abstract ( 585 )   Save  In order to solve the problem of poor efficiency and low accuracy in solving fluidsolid coupling problems, the method of increasing dimension precise integration is introduced. According to the finite element theory, fluidsolid coupling equation can be derived; then the equation is written in the form of state space. The dimension of augmented matrix only enlarges one, and the integration is transformed into algebraic operation. It expands the scope of application of the precise integration method. The results show that because the inverse matrix of the iteration matrix H need not be solved, the instability of the computational solution caused by the singularity of the matrix is avoided. By comparing the results calculated by using the augmented precise integration method and the Newmark method, the results of the two ones are consistent, and in the case of a larger computation time step the proposed method does not affect the accuracy of calculation. References | Related Articles | Metrics

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Industrial Water Use Efficiency Index and Its Influencing Factors  Under  the Background of New Industrialization MIAO Zhiping1,ZHANG Feng2 2017, 51 (6):  761-768.  Abstract ( 639 )   Save  The connotation of the new industrialization development was as the guiding ideology, and cloud model was used to build the index of industrial water use efficiency and measuring index system including “economic developmenttechnological progresswater regulationecological regulationsocial security”, and then correlation functions were combined to evaluate the index of industrial water use efficiency. The result of historical sequence measuring shows that although the industrial water use efficiency had some shortterm fluctuations, but it kept rising on the whole during 1997—2014, and also had a great room for improvement. The result of transverse section measuring shows that the industrial water use efficiency of different regions had a larger difference, so it needs to be optimized urgently in the spatial dimension. The result of future drive measuring shows that industrial water use efficiency could be further promoted, but some short indicators would affect the development of it, such as the low efficiency of technology innovation and achievements transformation, high water consumption rate and scale and insufficient wastewater treatment and monitoring ability, etc. So these short indexes should be resolved urgently. References | Related Articles | Metrics