Abstract:Aiming at solving the defects of risk priority number (RPN) in mathematics, ingredients and research object, classic RPN method is analyzed. And an improved RPN method facing to intermittent fault of electronic system is presented. This method estimates failure times O by fivestate Markov mode, the correlation and influence analysis of fault location, mechanism and mode are carried out by DEMATEL method, and the results which have the same sequence number in RPN first sorting are sorted by Mahalanobis distance. This method solves the problems well, for instance, classic RPN value is not a continuous integer, RPN result is sensitive to fractional changes of three key information factor S, O and D. The improved RPN computing model is applied to analyze intermittent fault case of a sea based equipment, which can get objective risks prioritization of different intermittent faults, and a good result is obtained.

Abstract:Aiming at the degradationcaused gradual changing fault diagnosis of aeroengine, this paper proposed a diagnosis model based on the canonical time warping (CTW) algorithm, which can discriminate the fault pattern based on the transition features from degradation data via mining the transition information of degradation. We conducted the proposed model on both simulated data and real data. The experimental results show that the proposed model can recognize the normal state and fault state and locate the gradual changing fault in component level, whoseG－meanvalue is 0.948 7 in the premise that the flight cycle interval is 1 or 2. The proposed model provides a feasible engineering method for civil aviation aeroengine health management, and has good robustness and high accuracy.

Abstract:In order to predict the remaining useful life (RUL) of rolling bearing accurately, a RUL prediction method of rolling bearing based on multiple criterions effectiveness analysis (MCEA), kernel principal component analysis (KPCA) and combined support vector regression machine (SVR) is proposed. For extracted feature, the effectiveness score of each criterion can be calculated, and the weight of each criterion can be determined adaptively, the feature will be sifted when the effectiveness total score of which is greater than its overall average, and the KPCA is used to remove the information redundancy among the sifted features, then the reduced feature matrix is established. The reduced features of multiple bearings are used respectively as the input of the SVR, the ratio p of the bearing running time to the whole life time, namely RUL are used as the output, multiple SVR models are established. And the selfadaptive method is used to determine the weight of each SVR model, the combined SVR prediction model can be established at last. Finally, the bearing which is different from the training process is used for testing, the reduced features are used as the input of the combined SVR prediction model, the p value of the bearing is predicted. The experimental results show that the RUL of the rolling bearing can be predicted accurately by the proposed method.

Abstract:Early fault signal of rolling bearing usually presents nonstationary multicomponent characteristics, early fault features of bearing submerged in the background noise are difficult to identify because of the weak modulated characteristics and strong noise. Therefore, the fault diagnosis method based on variational mode decomposition (VMD) and autocorrelation analysis was proposed．At first, the noise was eliminated and the periodic components in signals were extracted by using autocorrelation analysis. Then VMD was used to decompose the denoised signal into many intrinsic mode functions and the IMFs of the biggest coefficient and kurtosis was selected and demodulated with Teager energy operator. At last, the bearing fault type was distinguished through the energy spectrum. The simulation experiments and practical engineering experiments have been carried out and the results show that this method is able to reduce the interference of noise and extract effectively the fault feature frequency, and realize accurate diagnosis for rolling bearing fault.

Abstract:For further study about diagnosis of the fault type and location forthe rolling bearing, the method by using the acoustic array signals analysis with EEMD decomposition is proposed.Based on the kurtosis and power index values, the EEMD decomposition is carried out and the IMF component including faults information is extracted. After computing the theoretical fault frequency and the harmonics of the bearing’s components, the narrow band filter is used for the extracted IMF component and Hilbert transform is done consciously for envelope spectrum, which is used to determine the fault type. Also the extracted IMF components filtered with narrow band filter for each acoustic array signals are used as input signals for the acoustical image analysis to the fault location. Finally, the verified experiments are carried out and results showed thatby using this method the diagnosis could be more intuitive to determine the fault location and fault types, which is better forthe bearing fault determination of the drive system, the maintenance and reasonable maintenance decision and improving the service quality.

Abstract:A spur gear tooth number and missing teeth identification algorithm based on minimum convex hull and convex defects of outer contour is presented in the paper. Firstly, the connected domain of binary image is adopted to trace the outer contour of gear. Then, the minimum convex hull and convex defects of outline are detected, and fake convex defects need to be removed before identifying tooth number and missing teeth part. According to the shape characteristics of spur gear, an addendum circle detection method based on the convex hull vertices of gear outer contour and a dedendum circle fitting method based on the deepest point of convex defects are proposed, which have realized the rapid measurement of characteristic circle parameters of spur gear. The experimental results show that the accuracy of the proposed tooth number and missing teeth recognition algorithm is as high as 98.48%. Compared with the existing two kinds of typical methods, the proposed characteristic gear circle fitting method can achieve high speed and high precision positioning of addendum circle and dedendum circle under various conditions.

Abstract:Aiming at the problem that the method of positioning the bottle bottom center is not accurate and the results for detecting the antiskid grain areas of bottom are unreliable, by taking advantage of the geometric features of antiskid grain areas on the bottom of the bottle, a localization algorithm based on variable weight random circle fitting the bottom is proposed in the paper. First, the bottom center is quickly prepositioned by gravity method, then the random variable weight circle fitting method is used to realize the precise positioning. Finally, the suspected defect region of the bottle bottom image is detected, and area, contour length, average gray, gray variance and circularity are extracted, then the support vector machine is used for classification and the defect is detected. The experiment results show that the positioning error of this method is less than 6 pixels, and the detect accuracy is 92.7%. It basically meets the actual production requirements.

Abstract:Aiming at solving lacking of failure data and low efficiency of composite material damage detection, a fault diagnosis method based on principal component analysis（PCA）and support vector machine combined with the rotation symmetric partition（RSPSVM）was proposed. Firstly, the model of uniplanar multielectrode is partitioned into equal area units with rotation symmetry partition, and fault data is acquired adequately. Secondly, genetic algorithm（GA）was introduced into RSPSVM in order to promote the classification performance, and PCA was used to reduce the dimension of feature vector and shorten training time, the final features were put into improved RSPSVM so that PCAGARSPSVM was achieved. Finally, the measured data of three composite material samples were sent to PCAGARSPSVM for verification. After verification of the simulation data and the measured data, the effective certificate of general PCAGARSPSVM algorithm is applied to the diagnosis of damage of aircraft composite material.

Abstract:The circumferential liquid film distribution is asymmetric, and it plays an important role in studying the mechanism for transport of liquid. In this paper, a conductivity probe array for circumferential liquid film characteristic measurement in horizontal annular flow is designed based on indirect conductivity measurement principle. Combined with crosscorrelation velocity measurement, it is realized that the distribution of circumferential liquid film thickness and circumferential wave velocity is measured respectively. As for the signal coupling issue between the probes, it is acknowledged that the circumferential probe must work in different time and the axial probe can work together after simulation analysis. A measurement system for liquid film parameter based on FPGA is designed. The experiment is implemented on Tianjin University moisture setup, and the result shows that the liquid film thickness decreases with the increase of angel and the wave velocity remains the same with the increase of angel.

Abstract:In recent years, all kinds of deformed micronano cavities with high quality factor and directional output have been extensively studied, since they can be widely used for the realization of the extremely low threshold lasers in optoelectronic integrated. In this paper, we calculate the variation of mode pattern, quality factor and far field characteristics as the cavity evaluates from circular to ellipse with the changes of the short half axis changes using the boundary element method. The simulation results show that the larger the ellipse curvature is, the lower the mode quality factor, and the mode field transforms from the whispering gallery mode to the regular Fabryperot cavity mode. However, during the deformation transformation, the mode coupling effect leads to the abnormal change of the mode quality factor, and the modulation of the far field. This mechanism provides a new design idea for the laser with both directional output and high Q value.

Abstract:Aiming at the problem that the measurement accuracy of HMP45D temperature and humidity sensors used in automatic weather station is susceptible to temperature, the fitness function, selection, crossover, mutation in genetic algorithm (GA) is improved, the improved GA is used to optimize the penalty function, radial basis function and insensitive loss function in support vector machine (SVM). Based on the multiple sets of experimental data under different temperature and humidity, this method is used to establish a model and the results are compared with the traditional SVM regression model for temperature compensation. The experimental results show that the absolute error using the GASVM model is 0.1367%, reduced by 2.8351% than traditional SVM model. The proposed algorithm overcomes traditional SVM compensation model with low precision, slow process speed and has global optimization, convergence speed, higher compensation accuracy, effectively compensates temperature effect and greatly increases the measurement accuracy.

Abstract:Aiming at the problem of excessive deviation and jitter in the process of floating and impacting stator surface in the process of descend in the sensorless control on movingcoil permanentmagnet planar motor, this paper analyzes the maglev up and down moving process under the control of realtime current distribution strategy, proposes the concept of “false airgap point”, deduces the mathematical equation between the position of "false airgap point" and the desired airgap position and the time calculation integral formula that when mover moves up to desired airgap position and descends to zero altitude.The “false airgap point” has two reflections. One is that when the mover stays at the zero position, the coil is assigned a "false airgap point" constant current and the speed of the mover running to the desired airgap point is zero on the condition of the current drive. The other is that when the mover floats at the desired airgap position, the coil is distributed “false airgap point” constant current and the speed of mover running to zero position is zero as the result of the current drive. The control strategy utilizes the phenomena mentioned above, and moves the mover smoothly between the zero position and the airgap point by switching the current. The simulation result shows that the mover running deviation and the jitter are very small, which proves the validity of control strategy.

Abstract:In order to detect common point and line defects on TFTLCD panels, a defect detection algorithm combining weighted template difference image method and bilateral filtering is proposed. The image is divided into several units with the same size, in which an ideal texture template with the size of l×k in the upper left corner is selected. These units are synthesized after subtracting the weighted template in order to remove most of the texture background. The suppression of residual texture background is achieved by bilateral filtering. The maximum entropy threshold segmentation method is used to realize the defect segmentation. Finally, the defect parameters in the image are extracted. It is proved that the algorithm can detect the defects on the TFTLCD panel image through testing the constructed theoretical defects image, and it is verified that the defects of pinhole, scratch and particles are successfully detected. The proposed algorithm combines the advantages of the wellbackgroundremoving performance of the difference image method and the effective denoising of bilateral filtering, which has good accuracy and applicability.

Abstract:Mode locked fiber laser has the properties of high peakpower and narrow pulsewidth, and can be effectively applied in highaccurate remote ranging and information transmission. In the paper, a method of realizing dualpulsetrain modelocked laser in an allpolarizationmaintaining Erdoped fiber cavity based on graphene saturable absorber is reported. Based on multilayer graphene saturable absorber mirror, stable modelocked fiber laser can be obtained, and cavity loss can be operated by modulating an attenuator in the cavity. By adjusting the gain and loss of laser signal at different wavelength, dualpulsetrain laser centered at 1 531 nm and 1 557 nm can be realized, repetition frequency 57 MHz and extinction ratio of output laser can be up to 19 dB.

Abstract:The availability of continuouswave tunable light source in the midinfrared region is valuable for atmospheric sounding, industrial production, medical diagnosis, etc. 1 060 and 1 550 nm band narrow linewidth laser is used as the fundamental light source, the midinfrared light source based on difference frequency generation (DFG) and quasiphasematching (QPM) technique has been realized in a periodically poled LiNbO3 (PPLN) crystal. The conversion efficiency, the temperature and the wavelength tuning characteristic of the midinfrared light source are studied experimentally. Based on the results described above, a gas detection system based on the midinfrared DFG laser source is constructed and the absorption spectrum at 2 999.01 cm-1 of v3 fundamental vibrational band of CH4 molecules is measured by scanning the wavelength of the pump laser.

Abstract:The accuracy of infrared body temperature measurement is affected by many factors, which is characterized by nonlinearity and high complexity. In order to improve the accuracy of infrared body temperaturemeasurement, the influence of ambient temperature, measurementdistance and emissivity on the accuracy of infrared body temperature measurement analyzed. The temperature field diffusion model of the hip surface temperature is transformed into the actual body temperature of the human body. The partial least squares method and the artificial neural network are used to optimize the temperature field model, which effectively solves the problem of the temperature field diffusion method. The problem of multiple correlation between influencing factors and the nonlinear problem of compensation modelare served effectively, and the reliability of the system is improved. The experimental results show that the temperaturemeasurement error of the proposed infrared temperature compensation model is -0.12~0.11 ℃, which has higher measurement accuracy and stronger adaptability.

Abstract:Aiming at the low efficiency, high risk and high cost in manual ship descaling, the wallclimbing robot is developed. This paper adopts the distributed control scheme of host and slave machine to research the controller of the wallclimbing robot based on ARMLinux, including the sensor, the comparator, and the composition of the circuit. By using the reinforcement learning algorithm QLeaning algorithm, the reinforcement learning tracking of wallclimbing robot is realized. The weakness that traditional PID and other algorithms that can't optimize the action strategy for environment are improved and the wallclimbing robot in different environments tracking accuracy is raised. The experiment results show that the control system of the wallclimbing robot based on ARMLinux can perform better and meet the requirements of the controller.

Abstract:In order to meet the requirement of accurate measurement of widerange microcurrent in the electrochemical analysis system, a novel widerange precision potentiostat with low power dissipation is designed in this paper. New detection method based on compensated potential control and twostage proportional resistance method is proposed to achieve accurate measurement of microcurrent in the widerange of 10-10~10-3 A. The hardware circuit design of novel widerange precision potentiostat with low power dissipation is proposed, the transmission characteristic of the circuit is deduced by equivalent model circuit, and the bioelectrochemical analysis process is simulated by using homemade threeelectrode needle sensor and high precision resistors. The simulation and experimental results show that the signal output of the novel widerange precision potentiostat with low power dissipation is stable, the relative error of microcurrent detection in the widerange of 10-10~10-3 A is less than 1%, and the novel portable potentiostat according to the proposed method has practical application in tissue engineering hydraulic bioreactor intelligent monitoring system.

Abstract:To solve the problem of stacked papers counting, the method combined minimum curvature with peak detection is presented. First, the profiles of the stacked papers along the vertical orientation of the paper are extracted. The curvatures of the profiles are calculated after processing the images by Gaussian filtering. Second, the centers of the stacked papers need to be detected. As the profile of the sheet is like the shape of Gaussian. So, the local minimums of curvatures indicate the center positions of stacked papers. The width of the region where the curvature is negative represented the thickness of the paper. Then the center positions of stacked papers can be corrected by judging the distance between the two adjacent center points and the gray features. Finally, the counting result can be acquired by using peak detection from the ultimate ridge line result of the stack papers. The algorithm proposed in this paper can accurately detect the abnormal paper by fusing the gray features of the stacked papers and the distance of adjacent paper. The experimental results show that the error rate of the method is less than 0.01% for the paper with the thickness between 0.05~0.2 mm.

Abstract:In order to improve the reliability of distributed storage systems and repair efficiency of failed nodes, locally repairable codes based on Pyramid codes are proposed in this paper. Specifically, adopting the minimum achievable encoding structure of Pyramid codes, the proposed locally repairable codes divide the nodes of distributed storage systems into multiple local repair groups, to achieve lower repair locality and rapid repair of failed nodes. The performance analysis shows that, the proposed locally repairable codes based on Pyramid codes can achieve rapid repair of multiple failed nodes in distributed storage systems, has lower repair locality. Moreover, compared with three copy replication strategies and simple regenerating codes, the proposed locally repairable codes based on Pyramid codes have advantages in the performances of storage overhead and repair bandwidth overhead.

Abstract:To achieve an optimal balance between energy consumption (EC) and effluent quality (EQ) of a wastewater treatment process (WWTP), an intelligent optimal control strategy is proposed based on constrained barebones multiobjective particle swarm optimization algorithm (CBBMOPSO). First, a datadrivenbased fuzzy neural network prediction model of EC and EQ is constructed utilizing the process date measured from WWTP. Then, the proposed CBBMOPSO with adaptive disturbance is used for dynamically optimizing the setpoints of dissolved oxygen SO concentration and nitrate nitrogen SNO level. Furthermore, an intelligent decisionmaking system based on fuzzy membership function is designed to identify the optimal setting value from the Pareto optimal set. Finally, the optimization setpoints of SO and SNO are tracked by a fuzzy logic controller to realize multiobjective optimal control of the WWTP. The experimental results based on the international benchmark simulation model No.1 (BSM1) demonstrate that the proposed CBBMOPSO method can significantly reduce the energy consumption on the premise of assuring water quality.

Abstract:DempsterShafer（DS）evidence theory is widely used in the field of uncertainty reasoning and information fusion. However, there is also a problem of counterintuitive results in highly conflictive evidence combination. To solve this problem, an improved DS method based on conflict evidence correction is proposed. Firstly, the weight of each evidence is determined by the evidence distance of each evidence and average evidence. Secondly, conflict evidence is determined by the average weight, which is the threshold, and then it is discounted according to its weight. Dempster rule is utilized to combine conflict with other original evidences to get final results. The simulation results show that the proposed method can effectively improve the typical problem of classic DS evidence theory. Compared with other methods, the proposed method is simple, effective and has fast convergence and high reliability when dealing with both low conflict evidences and high conflict evidences.

Abstract:In order to improve the voltage transfer ratio of matrix converter and accelerate its application in the field of power transmission, a novel ACDCAC Sepic matrix converter based on matrix rectification and AC chopper is presented in this paper. Firstly, the topology and working principle of Sepic inverter is introduced. Based on the above analysis, the topology of Sepic matrix converter is also introduced. Then, the modulation strategy used in rectifier stage and inverter stage is expounded. Finally, the correctness of the topology and the feasibility of the modulation strategy are proved by simulation and prototype experiments. The simulation and prototype test results show that the voltage transmission of this system can reach 1 and above, which breaks through the traditional voltage transfer ratio of matrix converter 0.866 maximum limit, and the system output voltage and current waveform distortion is very small, so it has good value of research.

Abstract:Autonomous bolt tightening is a challenging task for maintenance robot on power transmission lines, because bolts could hardly be traced and recognized without manual command. In this paper, a structure of bolt tightening robot and its bolt tracing, recognition and positioning strategy utilizing vision detection are proposed. The bolt tightening robot is equipped with a camerainstalled bolt tightening unit which is connected by an arm with three joints, the proposed bolt detecting strategy consists of two steps. First is bolt tracing in which the drainage wire is used as a reference, through the visual detection of the location and direction of the drainage wire, the bolt tracing task can be carried out by tracing along the wire, thus the tracing process is simplified and the difficulty of vision recognition in complicated environment is reduced. The second step is bolt recognizing step in which an improved Hough transform is proposed and the center of the circle shape edge is utilized to verifying the recognizing result. To make the bolt detecting more reliable, an initial classification algorithm utilizing HOG and SVM techniques is applied at the very beginning. The experimental results show that the proposed strategy can detect the bolt efficiently and pave the way for robotbased automatic bolt tightening live work on lines.

Abstract:In order to improve the control performance of permanent magnet synchronous motor (PMSM) with exogenous disturbance, a disturbance observer (DOB)based backstepping control strategy for speed regulation is proposed in this paper. First, aiming at the dynamic disturbance originated from the external system of PMSM, a disturbance observer is constructed by using system state variables. The design problem of DOB is transformed into the stability problem of system error. Furthermore, based on Lyapunov stability theory, the existence condition based on linear matrix inequality and design method of DOB are obtained. Next, on the base of realtime reconstruction of the dynamic disturbance, a backstepping control strategy is designed, which makes the system has good performance of speed tracking, torque response and disturbance rejection. Finally, the effectiveness and feasibility of the designed system are verified by Matlab simulation and experiment results. The simulation results show that when the setting speed is 500 r/min, the time required for the motor starting to reach the steady state is shortened from 0.025 s to 0.008 s, and the peak speed of the motor is reduced from 680 r/min to 520 r/min compared with the traditional PID control. The DSPbased experimental results show that the proposed control strategy has the advantages of fast response, small overshoot, high steadystate accuracy, and can effectively reject the load disturbance.