Shearer Localization And Degradation Prediction Of Electro-Magnetic Valve For Electro-Hydralic Control System Of Hydralic Supports

Roof support is the most important thing for mine produtcion safety, yield and efficiency in underground longwall coal mining. The safety, reliability and automation of the roof support system directly relate to the safety and production efficiency of coal production. As the core of the hydraulic support system, the hydraulic support electro-hydraulic control systems used in China mainly depend on foreign imports. The high price, long delivery time and expensive spare parts of the imported foreign products can not meet the needs of coal mine conditions of China. Therefore, consulting the advanced electro-hydraulic control system, and considering the mine environment of China to realize the domestic of electro-hydraulic control system have important economic and social significance for getting rid of the dependence on foreign products, accumulating the relevant technologies, improving the mining automation level, and reducing coal mine accidents. In this technology context, the hydraulic support electro-hydraulic control system is developed in this dissertation. To realize shearer coal linkage, rapid fault localization and prediction, and improve the safety and procuction efficiency of coal production, the mehtods of shearer localization and fault prediction for key equipent are researched.The mining system architecture, the mining process, and the advanced hydraulic support electro-hydraulic control system are analized. The power supply pattern, networking, isolation pattern, control functions, control process of electro-hydraulic control system for roof support system in underground longwall coal mining, and a single hydraulic support controller with its matching equipments are researched, which provide effective reference for following reseach.The hydraulic support electro-hydraulic control system is developed. The electro-hydraulic control system consists of a number of serial connected hydraulic support controllers. A single hydraulic support controller is mainly consisted of a main controller and an electromagnetic valve controller. The sequential power on method is proposed. By releasing the control right of valve control after ensuring that the pin states of the electromagnetic valve control loop are convinced, the longwall face collapse caused by unconvined pin states during reseting is avoid.Integral synchronization type infrared wide-angle transmitter and receiver are designed, and the localization methods based on received infared signal strength are researched. The actual models of signal conditioner and photodiode are analized. The instability of I/V conversion circuit is analized as well. Through lead compensation, the zero is introduced to the feedback coefficient to compensate the pole and the phase shift caused by the real model of the circuit, and reduce the slope of the loop gain for the purpose of making the system stable. The method of communication based infrared signal synchronization integration is proposed. The problem of signal synchroniaztion is solved, which ensure that the received analog signal strength only relates to the relative positions of transmitter and receiver. The infrared signal strength distributions of sevral neighbored receivers near the launch position of transmitter locatted on the shearer are analized. The localization methods at the cases of the reciever being shielded and not shielded, and the methods of tracking and prediction for the runing rate of shearer based on Kalman filtering algorithm are proposed to improve the accuracy of localization.The mechanism charateristics and the electrical parameter model of the electromagnetic valve is analized. The platform for real-time fault diagnosis of electromagnetic valve and coil current degradation data acquisition is designed. The degradation feature extraction methods are researched. As the key device that converts the electrical control signal to hydraulic control signal, the mechanical structure and character of mechanical movement of the electromagnetic valve are analized. The electrical model of electromagnetic valve is established. The characteristics of transient process of the coil current in normal and fault states are analized. Based on the platform, the degradation coil current data of the electromagnetic valve runing until fault is acquired, and the degradation characteristic of the dynamic process of coil current is analyed considering the electrical parameter model. The methods of template matching, K-L transform, wavelet transform, the cloud theory etc. are used to extract the degradation features of electromagnetic valve.The neural network based degradation qualitative classification and prediction method for electromagnetic valve is researched. The degradation trend feature enhance method based on limited Kalman filtering algorithm is proposed to reduce the influnence of mutation information in the extracted features caused by transient fault which reduces the performance of neural network. The LVQ network, GRNN network, PNN network etc. are used for degradation qualitative classification and prediction with the trend enhanced features as inputs of the networks. The prediction results of the five common used networks on the same conditions of simulation platform and samples are compared.