Movement criterion of top-coal drawing mechanical parts for safe transportation of drawn coals on rear conveyor and accurate control approach for drawing opening dimension

The accurate control of the top-coal drawing mechanical parts is of significance to realize the automation and intellectualization of top-coal caving process, while mastering the spatial motion law of top-coal caving mechanism is the premise of accurate control. The top-coal caving process is jointly controlled by hydraulic support height, extension length of the plug plate of hydraulic support, and the relative position relationship between rear scraper and hydraulic support. Those three factors dominate the top-coal drawing opening dimension and the drawn coal transportation height of rear conveyor. In this study, a 3-D numerical model of four- legs top-coal caving hydraulic support is established by using hinge and translator connectors for modeling the rotation behavior of joints and expansion-contraction behavior of plug plate. The spatial motion laws of the top-coal drawing mechanical parts are modeled under different support height ( H ), tail beam swing angle ( α ), and the plug plate extension length ( l ). The critical equation for evaluating collision between top-coal drawing mechanical parts and rear scraper is fitted by using Levenberg-Marquardt fitting iteration method. A database for describe the coordination of plug plate and the dimension of the top-coal drawing opening under different H , α , and l , is obtained. The sensor type and installation position for sensing and controlling the position of top-coal drawing mechanical parts are selected, the approach for calculating the tail beam angle based on travel sensor data is derived, and the approach for controlling the top-coal drawing opening dimension is proposed and tested in the field.