Development Of Attitude Monitoring System For Hydraulic Support In Fully Mechanized Mining Face

The dissertation,aiming to solve the problem of hydraulic support attitude monitoring,is an extension of the National International Science and Technology Cooperation Special Project “Development of Electro-hydraulic Control System for Unattended Working Face Hydraulic Support”(2013DFA70750),which is proposed according to the automatic control level of the hydraulic support electro-hydraulic control system of the fully mechanized mining face.As the key supporting equipment for coal mine fully mechanized mining face,the safety and reliability of hydraulic support have an important impact on coal mining efficiency and production safety.However,the hydraulic support works in the coal mining face with harsh working conditions and large load changes.Simultaneously,unreasonable attitude of the bracket would cause the damage of key components and affect its service life and production effectiveness.In practice,as the top plate would tilt gradually due to the height adjustment of the shearer drum,the bracket of the entire fully mechanized mining face could hardly be in an ideal attitude.The lifting and lowering attitude of the top beam could seriously affect the supporting effect on the roof,which may cause the shielding beam to be forced to bear and reduce the roof area,leading to the decrease of overall supporting capacity of the bracket.However,the research on attitude monitoring of hydraulic supports at home and abroad is mainly concentrated in the field of theoretical analysis and simulation.Therefore,it is of significance to develop a hydraulic support attitude monitoring system meeting the actual requirements of coal mining face for unattended fully mechanized mining face.The dissertation analyzed the dynamics of research at home and abroad from two aspects of hydraulic support development and attitude monitoring technology,and summarized the research results of hydraulic support attitude monitoring,pointing out the inadequacies of hydraulic support in attitude monitoring in coal mine informatization and putting forward the research goals.On the basis of analyzing the structural characteristics and various attitudes of the hydraulic support,the hydraulic support was simplified into a planar rod hinge mechanism,and a two-dimensional model of the shielded hydraulic support was established.By formula calculation,the coordinates of the hinge points and the height of the support were determined.Combined with the attitude calculation method,on the basis of determining the attitude monitoring object and the detection parameters,the overall design scheme of the hydraulic bracket attitude monitoring was formulated in terms of system function and system structure.As condition monitoring was the key part of the monitoring system,the tilting angle monitoring device based on ADXL345 accelerometer,including the minimum system circuit of single chip microcomputer,peripheral circuit of ADXL345 accelerometer,reset circuit,power conversion module,was designed,and the calculation method of tilt angle based on gravity acceleration was proposed.Simultaneously,the detection substation with C8051F020 MCU and RS485 as the core,including pressure sampling and conditioning circuit,external RAM storage circuit and RS485 communication circuit as the hardware circuit,was designed.On the basis of it,the software program,containing main program,CRC check program and communication program,was designed to realize the real-time collection,accurate processing and reliable transmission of the hydraulic support attitude monitoring information data of the fully mechanized mining face.Combined with MySQL database software,on the basis of effective collection of attitude data,the upper computer operation platform,including four modules(data acquisition module,attitude monitoring module,parameter setting module and data management module)based on LabVIEW software wasdeveloped,which could realize real-time display of attitude information of hydraulic support,parameter setting,database management,data query and remote release.In order to verify the effectiveness of the system designed,the hardware,software and host computer of the attitude monitoring system were tested on the experimental platform established in the laboratory.The test results show that the hydraulic support attitude monitoring system is reliable and stable in performance.It not only could monitor the attitude of the hydraulic support in real time,but also the monitoring error meets the design requirements,which provides technical support for the construction of the unattended working surface.