| The automatic control system of the fully mechanized mining face is an important basic technology for intelligent coal mining,and it needs to be verified and optimized through system tests.The function test of the control system of the fully mechanized mining face is often tested and improved during actual production process of the mining face,but heavy production tasks of the coal mine have caused the contradiction between the production of the face and the function verification test of control system.Automation functions have not been fully validated and improved.Using hardware-inthe-loop simulation to verify the automatic control strategy of the fully mechanized mining face can effectively solve the complexity of the test at the coal mine site and the problem coal seam cutted is unrecoverable.The core of building the hardware-in-theloop simulation system is to build the mathematical model of simulation object.This paper mainly researched the process of pushing and pulling,built the mathematical model of its operation process,and laid theoretical foundation for the realization of the hardware-in-the-loop simulation system of the fully mechanized mining face.Through related research,the following conclusions was obtained:(1)Considering various factors such as the structure size of the device,forces generated by roof and floor and resistance generated by falling coal,mechanical model of hydraulic support during push-pull process was proposed.Through simulation experiments,it was found that pushing load was mainly affected by resistance generated by falling coal during the process of hydraulic support pushing a single middle trough;The squeeze collision between adjacent middle troughs would lead to mutation of pushing load during the pushing process of multi-segment middle troughs;The load of advancing hydraulic support reduced slightly with the decrease of angle ? between the piston rod and coal seam floor.(2)According to the working principle of advancing control circuit,mathematical models of quantitative pump,electro-hydraulic directional valve,hydraulic control check valve,relief valve,hydraulic cylinder were established.The hydraulic model of the advancing control circuit was established based on cavity-node method.(3)On the basis of the mechanical model of hydraulic support during push-pull process and the hydraulic model of advancing control circuit,mechanical-hydraulic coupling simulation model of advancing system of hydraulic support was proposed.Through simulation experiment of pushing middle troughs,it was found that since the resistance of falling coal augmented with increase of the moving distance of middle trough,pushing loads of the cylinders stepping together were different.Difference in pushing load caused action of pushing cylinders were out of sync;The synchronization of stepping of pushing cylinder decreases with increase of the load difference.The longer time-consuming cylinder was affected by the flow concentration,the smaller the effective area of the piston rod cavity,the greater the impact of flow concentration on pushing cylinder,and the greater the execution error of pushing cylinder,the more advanced the trajectory of the scraper conveyor;Abnormal load increased the local curvature of scraper conveyor.Through the simulation experiment of advancing hydraulic support,it was found emulsion in the piston rod cavity was squeezed and pressure energy was stored near the end of advancing hydraulic support.The release of pressure energy caused the piston rod to rebound slightly.The peak of displacement and rebound amount of the piston rod were different when different types of hydraulic supports were advanced,displacement error of hydraulic supports were also different finally;Abnormal load would reduce the synchronization of advancing hydraulic support,which caused the decrease of straightness of hydraulic support.(4)On the basis of the mechanical-hydraulic coupling mathematical model of advancing system of hydraulic support,the detailed design and development of the mechanical-hydraulic coupling simulation software of the advancing system of hydraulic support were realized based on MATLB-GUI.There are 75 figures,10 tables and 103 references in this paper. |
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