Advanced Materials Research Vols. 466-467

Abstract: Random drift is a significant index that can affect the precision of MEMS gyroscope. It is one of the important techniques to decrease the random drift error in improving the precision of MEMS gyro. According to analyzing the principle of traditional Wavelet Transform and Stationary Wavelet Transform, Stationary Wavelet Transform (SWT) is adopted to de-noise the signal of MEMS gyro. Due to SWT’s time-invariant, the Gibbs phenomenon is decreased. SWT with adaptive threshold is adopted to analyze the actual dynamic MEMS gyroscope data. The experimental results show that this presented method is better than traditional wavelet threshold de-noising methods. It can effectively restrain the noise in high frequency and improve the drift error of MEMS gyro.

Abstract: Reynolds equation for gas bearings is a nonlinear partial differential one and its analytical solution usually is difficult to obtain. Therefore numerical method is an effective means to investigate the performance of gas-lubricated journal bearings. In this paper, firstly the modified Reynolds equation for micro gas journal bearings based on Burgdorfer’s first order slip boundary condition is put forward. The finite difference method (FDM) is employed to solve the modified Reynolds equation to obtain the pressure distribution for micro gas journal bearings under different reference Knudsen numbers. Numerical analysis shows that the pressure profiles for micro gas journal bearings decrease obviously with the reference Knudsen number increasing.

Abstract: Comprehensive performance evaluation for aero-engine is essential in the stage of operational management in an airline company. Based on the features of aero-engine, this paper focuses on the implement of fuzzy comentropy method which is combined of fuzzy mathematics and rough set theory in the practical performance evaluation of aero-engine. By comparative analysis with principal component analysis, this paper reaches the conclusion that the fuzzy comentropy method has more advantages of computer programming, being free of expertise, preventing information loss. However, the accuracy of multi-parameter evaluation method depends upon the information content provided by the initial data; therefore, the pre-processing of data in decision-making and method itself are still worth in-depth study and improvement.

Abstract: In order to study the effect of patch shape on the strength of the damaged skin after rivet repair, the paper uses the elastic-plastic finite element method to analyze the rivet repair of the circular hole damage and gives the rivet loads of all the rivets under the three shapes of patches respectively. The results show that the circular patch can observably improve the strength of the aircraft skin after rivet repair, compared with the right-angled rectangle patch and the fillet-rectangle patch, in the same condition of the patch materials and rivet parameters and technology equipments. The design can enhance the security of the repaired aircraft and have some values for the peacetime repair and the emergent repair of aircraft structure.

Abstract: Introduced a kind of method which can establish machinery parts library based on Pro/E, the practical method is easy to grasp. The process of forming parts library is showed combing with Link Wheel living modeling. At the same time, gave the corresponding two-dimensional projection drawing.

Abstract: This paper proposes the conception of stepper motor controller’s design on the basis of the principle and algorithm of fuzzy BP network. It realizes the control function by identifying the consequent parameters. After taking some simulation experiments, the system control performance is good, the system operation is stable, and no runaway phenomenon has happened.

Abstract: In order to obtain accurate load forecasting of coal-fired unit, a new algorithm based on Support Vector Machine (SVM) method is presented. This algorithm establishes a model to reflect the complicated relation between the load of coal-fired unit and the furnace flame Images. The trained SVM model is applied to a 660MW coal-fired unit to forecast the load with two groups of test samples. The results are compared with that of BP neural network model. It is shown the SVM model is more accurate than the BP NN model. The SVM method can satisfy the demand of engineering applications with the advantages of high forecasting accuracy and more generalized performance.

Abstract: To improve the efficiency and precision of missile servo mechanism testing, as the research object, a certain missile servo mechanism was studied in this paper. Based on PC/104 bus and virtual instrument technique, a missile servo mechanism automatic test system was presented, and the design and development on hardware and software of the system was described in detail. The system, which is featured with its simple operation, high precision, high reliability, scalable and portable test software, has been proved to be feasible by the test result.

Abstract: Considering the complexity and relevance of fault diagnosis for turbo-generator, the paper makes diagnosis by adopting improved genetic BP network algorithm. In order to solve the problems of slow network learning and tendency of minimum point in BP algorithm, the structure and specific parameter of BP network optimized by genetic algorithm were used in the discussion of a model integrated with adaptive genetic neural algorithm, which was applied in the fault identification of turbo-generator. Experimental data shows that the algorithm is characterized by high convergence rate, effective vibration fault diagnosis for turbo-generator and relative high reliability and practicability.

Abstract: Using numerical simulation technology, coupling support mechanism of anchor-mesh-cable+ bottom-anchor has been analyzed. According to actual engineering of the Fifth Coal Mine of Hemei, the reasonable coupling support structure of anchor-mesh-cable+ bottom-anchor + truss under high stress has been analyzed. It is proposed roadway damage is twist deformation under high stress. By using the reasonable coupling support structure and parameter of anchor-mesh-cable+ bottom-anchor the high stress in underground rock laneway can be controlled and supporting effect is perfect.