Papers by Author: Xu Hui Zhang

Abstract: To solve the problem of faults location for shearer rocker gearbox, the multiple sites vibration signal of faulty rocker gearbox are collected, as well as the Morlet wavelet envelope demodulation is applied to demodulate vibration signal and Fourier transform is used to carry out frequency spectrum analysis of vibration signal. Experimental results show that this method can effectively extract the faults feature frequency from complex vibration signal. The faults location result is consistent with actual faults part. This mean realizes to locate faults accurately. It provides an effective method for mechanical faults diagnosis of shearer.

Abstract: SVM classification model has been widely applied to mechanical equipment fault diagnosis and material defects classification. It is difficult to choose the optimal value of penalty factor C and kernel function parameter for SVM model. Therefore, an improved genetic algorithm to optimize SVM parameters is put forward, which improves crossover and mutation operators and enhances convergence properties by using the best individual retention strategy. UCI data set is used to verify the algorithm. The testing results show that the algorithm can quickly and effectively select optimal SVM parameters and improve SVM classification accuracy.

Abstract: Aimed at the problems existed in remote monitoring system of shearer, this paper put forward a new remote control strategy of shearer based on virtual reality (VR) to achieve control visualization and automation of equipment in coal face. Firstly, after analysed the control demands of shearer in the automatic coal face, an overall scheme of coal mining machine virtual control system was put forward, its working principle and main composition were introduced also. Secondly, the methods and procedures for VR-based remote control system for shearer using Quest3D, such as virtual control platform, logic control, data transmission and communication were described. Finally, the experiments were carried out to validate and evaluate those technologies. The experimental result show that the VR techniques were the effective and efficient way to carry out remote control of mining equipment and to improve safety and reliability of production in coal mine.

Abstract: Exploring a proper wavelet base function to characterize fault information of mechanical equipment is a big problem when wavelet analysis is applied into the field of fault diagnosis.Improper wavelet base function can dilute fault information, which will cause difficulties in fault diagnosis , based on the principle that the wavelet domain oscillation waveform are similar to the detected signal components, a proper wavelet base function was selected; through wavelet transform on the acceleration signals of the fault bearing, the spectrum chart of fault signals and the frequency characteristics of fault bearing were obtained. The experimental result shows that this method has a great advantage over extracting character signals.

Abstract: Aimed at the frequent accidents of conveyor belt and the the lower level of belt fracture protection in coal mine, this paper introduces a novel device equipment, the Eectro-hydraulic type Blt Cpture Dvice (Eh-BCD) to achieve safe and reliable working of steel cord conveyor belt. Firstly, after analysed the typical capture device existing on the market and researched the mechanical properties of the instant belt, an electro-hydraulic control type capture device solution was put forward, its work principle and main modules were introduced also. Secondly, main parts force of capture device calculated using Newtonian mechanics, designed and calculated the mechanical structure of the device, and determined key parameters such as installation space. Finally, after kinematic model built and analysed, device response time parameters the electro-hydraulic controlling capture was estimated.

Abstract: Because of steel cord conveyor belt with high load operating and complex conditions of coal mine, it is prone to cause conveyor belt horizontal rupture. It will bring tremendous hazards for coal mine production. Twelve time domain features of joints signals, broken wires signals and abrasion signals for steel cord conveyor belt were extracted with weak magnetic detection system. The algorithm of combining rough set based on information entropy with multi-classbased on binary tree was proposed to classify the three categories signals. The experiment results show that rough set reduction algorithm based on information entropy can effectively achieve feature reduction and classification speed of multi-classclassification algorithm based on binary tree can be improved by rough set feature reduction without changing classification accuracy.

Abstract: Methane monitoring and alarm system is very important because it guarantees the coal mine production safety. After analyzing impact factors on methane monitoring, this paper established a mathematical model of gas detection system and introduced the key technologies for maintenance-free is dynamic adjusting of system state, auto-zero, auto calibrations of nonlinear and post-processing of the data. The hardware architecture of the mini intelligent methane sensor based WSN (Wireless Sensor Network) and the automatic and visualized calibration technologies of intelligent methane detecting system are described in detail. Finally, the experimental data is analyzed. The system improved the detection accuracy, prolonged calibration cycle of the methane measuring device and lessened the working strength on calibration.