Correlation load characteristic model between shearer cutting state and coal rock recognition

In terms of the thickness change of coal seam in coal mining face, the uncertainty of gangue and inclusion, as well as the difference in the proportion of complex coal-rock and the prediction of rock stratum position, they normally result in the ineffective adjustment of the cutting height of the shearer in the cutting process. In turn, it affects the reliability and intelligent technological level of shearers. The cutting behavior of shearer can be predicted, modified and decided through the load characteristic model of cutting coal and rock and its associated cutting state, and the intelligent degree of shearer can also be improved. The binary cooperative control mode of independent height regulation and speed regulation of shearer and the correlation feature model of cutting state are proposed based on using multi-information as reference, real-time correction, memory cutting and three-dimensional geological information modeling on coal seam. The drum cutting process is divided into forward cutting, reverse cutting, forward and reverse free surface cutting, cutting top and bottom plate and gangue by considering the occurrence conditions of coal and rock, the position and working parameters of the drum relative to coal and rock. The mathematical model of cutting state characteristic quantity of vertical and reverse free surface and the identification of cutting top and bottom plate position and proportion, and the quantitative load correlation characteristic model are developed by analyzing the process and state of cutting coal and rock with pick. At the same time, the calculation method of the cumulative proportion of the cutting force of the pick perpendicular and parallel to the bedding direction is obtained, and the accuracy of the cutting coal rock load characteristic model is verified by the rotating cutting experiment. Combined with the related load characteristic model of cutting state, the cutting state and rock stratum position are corrected and predicted, and the cutting state characteristic parameters of the coordinated control of the height and speed regulation behavior of the shearer are determined. The results show that the fracture position of coal-rock cutting towards the free surface is greater than that of the cutting away from free surface, cutting towards the free surface is easy to break coal-rock, and the cutting load and specific energy consumption are low. The load increment and direction angle of the pick cutting top and bottom plate are obtained respectively. The load increment is positively correlated with the rock thickness, but there is a noticeable difference in the direction of cutting top and bottom plate. With the increase of the thickness of the gangue rock stratum, the cutting load of the pick increases, and the relationship between the cutting load and the position of the gangue is parabola. The measurement of the characteristic value proportion of the cutting force in vertical and parallel to bedding is given, which reflects the characteristics that the cutting top plate is easy than cutting the bottom plate. The average errors of the characteristic value of cutting resistance work, fracture position and the angle between the fracture caving line and the vertical line of the theory and experiment of the pick cutting towards free surface are 3.10%, 3.37% and 8.07% respectively, which verifies the correctness of the mathematical model of cutting coal-rock state characteristic quantity. This study provides a theoretical support for the further accurate realization of intelligent shearer height-speed regulation binary coordinated control by giving the theoretical basis description of cutting state correction and coal-rock state recognition with integrating load characteristics.