采煤机截割状态与煤岩识别的关联载荷特征模型

Correlation load characteristic model between shearercutting state and coal-rock recognition

针对采煤工作面煤层的厚度变化、含夹矸和包裹体的不确定性,以及复杂煤岩占比和岩层位置辨识的差异,致使采煤机在截割过程中会产生无效调整截割高度的情况,影响其可靠性和智能化技术水平。截割煤岩载荷特征及其关联截割状态的模型可以预测、修正和决策采煤机截割行为,提升采煤机智能化程度。借鉴多信息实时修正记忆截割与煤层三维地质信息建模等方法,提出了采煤机自主调高-调速二元协同控制模式及截割状态关联特征模型,考虑煤岩赋存条件以及滚筒相对煤岩层的位置和工作参数,划分滚筒截割过程为顺转截割、逆转截割、向和逆自由面截割以及截割顶底板和夹矸等截割状态,分析截齿截割煤岩的过程与状态,构建了向和逆自由面截割状态特征量的数学模型和截割顶底板位置与占比的识别定量载荷关联特征模型,给出了截齿垂直、平行于层理方向截割力的累计占比计算方法,通过旋转截割实验验证截割煤岩载荷特征模型的准确性。根据截割顶、底板、夹矸岩层前后载荷变化导致的截割电机电流变化规律与调高液压缸两腔压力的关联性变化规律,结合截割状态的关联载荷特征模型,修正与预测截割状态和岩层位置,确定了修正采煤机调高调速行为协调控制的截割状态特征参量。研究表明:向自由面截割煤岩断裂位置大于逆自由面的,向自由面易于破碎煤岩,且截割载荷与比能耗均小;分别获取截齿截割顶底板载荷增量与方向角,载荷增量均与岩层厚度呈正相关性,但截割顶底板方向存在明显差异;随截割夹矸岩层厚度增加,截齿截割载荷增大,且截割载荷与夹矸位置呈抛物线关系;给出截齿垂直和平行层理截割力特征值占比的度量,反映截割顶板易于截割底板的特征;截齿向自由面截割煤岩理论和实验的截割阻力功特征值、断裂位置和断裂崩落线与截割点垂线夹角的平均误差分别为3.10%,3.37%和8.07%,验证了截割煤岩状态特征量数学模型的正确性。该研究通过给出融合载荷特征的截割状态修正与煤岩状态识别的理论基础描述,为进一步精准实现智能化采煤机调高-调速二元协调控制提供了借鉴。

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.