Applied Mechanics and Materials Vols. 241-244

Abstract: In order to improve the efficiency and reliability of fault diagnosis for the special electronic equipment, an intelligent fault diagnostic model based on Fuzzy Neural Network (FNN) is proposed. Firstly, the fault diagnosis model based on the FNN Expert System (ES) is built. Secondly, the fault diagnosis expert system of the special electronic equipment based on this model is introduced. Finally, experiments show that the proposed model is correct and the FD system is effective. Moreover, the given method provides a new way of fault diagnosis for other modern electronic system.

Abstract: There is the advantage of Rough Sets Theory for redundant condition reduction and D-S Theory for combination rules reasoning, one fusion approach based on the two theories was given. Firstly, the test data was discretizated and attribution reduced to get the reduction decision table. Then, the basic probability assignment was gotten through calculating the condition attribution of the decision table while the condition attribution was regarded as evidence input and the decision attribution as discernment frame. Finally, the evidence was combination reasoned and the fault diagnosis results were gotten, and the application example was verified its validity.

Abstract: In order to solve the problems of coarse alignment on swaying base of SINS, a novel method based on attitude quaternion is proposed. A decomposition of the objective initial attitude quaternion is given firstly. The time-varying parts can be derived from the quaternion update, and the invariable part can be obtained by using the integration of gravity. The problem finally becomes the Wahba’s problem. By using the FORM algorithm, the calculating process is optimized and the method can be easily used in engineering application. The final simulation verifies that the method proposed has higher accuracy than conventional methods.

Abstract: The EZW and Fractal Coding were researched and simulated in this paper. And two drawbacks were discovered in these algorithm:the coding time is too long and the effect of reconstructed image is not ideal. Therefore, The paper studied the wavelet transformation in the fractal coding application, The wavelet coefficients of an image present two characteristics when the image is processed by wavelet transform: first characteristic is that the energy of an image is strongly concentrated in low frequency sub-image, second characteristic is that there is a similarity between the same direction in high frequency sub-images.but the fractal coding essence was precisely uses the similarity of wavelet transform image. The paper designed one kind of new Image Compression based on Fractal Coding in wavelet domain. The theoretical analysis and the simulation experiment indicated that, to some extent the method can reduce the coding time and reduce the MSE and enhance compression ratio of the reconstructed image and improve PSNR of the reconstructed image..

Abstract: High and constant current charging and discharging is necessary to improve the precision of supercapacitor parameters measurment. In this paper, three topics are discussed for high-precision measurment of supercapacitor parameters. Firstly, the analysis of the principle of capacitance measurement was described. Secondly, a model of high and constant current control was presented. The model used in the system of supercapacitor parameters measurement was in order to ensure the constant-current accuracy. Finally, several software compensation methods were used to improve accuracy. And then, the experiment results between our system and the American Arbin Instrument Company’s Super Capacitor Test System were compared. The system designed by us shows good performance of high precision measurement.

Abstract: In order to apply silent chain on conveyor, double-pitch time-sharing meshing silent chain is proposed, and by comparing with traditional silent chain with same pitch, the self-weight 20%~30% of this chain is reduced. According to meshing theory, parameters are designed for double-pitch time-sharing meshing silent chain to make each tooth profile of chain plate involving in meshing and time-sharing load bearing and to change the meshing state of traditional silent chain in the meshing process. Noise comparison test is conducted to verify its excellent performance, when rotate speed is 350r/min, the noise of double-pitch time-sharing mesh silent chain is 4.6dB lower than traditional double-pitch roller chain. Meanwhile, 250h abrasion test is conducted, the abrasion elongation of chain is 0.23% after test, which is significantly lower than traditional double-pitch roller transport chain. The rationality of new chain design is proved by test result, which provides theoretical basis for applying silent chain on conveyor.

Abstract: Based on the former calibration data of error coefficient of inertial navigation instrumentation and environment parameters, a three-layer BP neural network is founded to predict the calibration value in current circumstances. To confirm the structure of neural network, genetic algorithm is used to seek the optimal solution, and hence the concept of genetic neural network is introduced. Also since the calibration data has small-sample characteristics; Bayes regularization method is adopted to improve the network generalization ability and predicted performance. In the end the simulated results show that it is reasonable and effective to accomplish the prediction in genetic neural network.

Abstract: It is important that scene matching algorithm should satisfy the requirements of real-time, robustness and high-precision for inertial integrated navigation system. And considering the serious distortion and speckle noises of SAR images, we proposed a new scene matching algorithm for the SAR/INS integrated navigation system with high-speed and robustness based on Oriented FAST and Rotated BRIEF (ORB). We started by detecting scale-space FAST-based features in combination with an efficiently computed orientation in the image. Then, we calculated feature point's Rotation-Aware BRIEF descriptor which performs well with rotation and match features by computing Hamming distance between descriptors. Finally, we adopted GroupSAC which are proposed recently to remove the false matching points and the least square algorithm for getting the distortion transformation parameters that are the aircraft position errors and rotation transform parameters between real image and reference image. Experimental results on real SAR images indicate that our algorithm is invariant to various image transformations due to rotation and scale, and also robust to speckle noise and extremely efficient to compute, better than SIFT in many situations. Therefore, our algorithm can meet the high performance needs for matching navigation in the SAR/INS integrated navigation system.

Abstract: This article introduces briefly the design feature of thread gauges used in the inspection of API round thread casing and coupling thread standoff, and expounds some questions relating to the extending amount, the positive and negative sign of standoff P and P1, the thread number of hand tight standoff A and the revising of short round thread standoff, which may be ignored easily in the control and inspection of the casing and coupling standoff. The article also gives the right inspecting procedure of the round thread casing and coupling thread to avoid erroneous judgement in the course of standoff inspection.

Abstract: The cross-type Czerny-Turner optical structure has been widely used in the portable fiber spectrometers.We investigated the relationship between the spectral resolution and the spatial parameters of the cross Czerny-Turner optical structure. The incident angle of the collimating mirror and that of the imaging mirror are the most important factors which affect the spectral resolution. The distances between optical elements have a little influence on the spectral resolution, which can be mostly compensated by adjusting the position of the CCD sensor. A experimental setup was built and the experimental results show good agreement with the simulation.