Research on Automatic Section Precision Forming of Boom-type Roadheader

Abstract

Abstract. The decision of the inflection point is the key to ensure automatic section cutting precision using a boom-type road header. In this paper, cutting precision model was set up for the first time to trapezoidal section and a method determining inflection point is given. Considered the cutting head' projection at section is elliptical with the cantilever's joint variable. The relationship between ellipse curve and cutting section boundary was investigated, and thereby sets up the cutting precision model. Approximate iterative method is used to finding the optimal inflection point, of which takes the cutting precision as the objective function. Compared with the traditional process path planning method, the forming accuracy can be improved greatly and controlled within 1mm. Through MATLAB simulation, it is proved that this method is correct and valid.

Research on Path Planning and Control Method for Secondary Autonomous Cutting of Cantilever Roadheader in a Large-Section Coal Roadway

“…The upper ordinate h 1 h upper = 3550 and the lower ordinate h 1 h lower = 0 were substituted into Equation (16) and Equation (17) to calculate the θ 2 , and θ 2 was then substituted into Formula (10c) to calculate the corresponding cutting head center coordinates z 1 h upper and z 1 h lower , and the vertical coordinates of inflection points 1~4 could be obtained. In the left half of the roadway, the abscissa of the inflection point was symmetrical; therefore, only the abscissa of one inflection point needed be calculated.…”

“…Ebrahimabadi et al and Jasiulek et al used a GA-BP neural network to enable the roadheader to identify the hardness of coal or rock in front of it when cutting, so as to improve the cutting performance [14,15]. Su et al established the cutting model of a trapezium roadway interface, determined the inflexion point position of cutting with an approximate iteration method, and simulated it with the MATLAB software, greatly improving the cutting shaping effect of the roadway [16]. Hu et al simulated the change law of stress and displacement of the surrounding rock of a roadway under different cutting paths by using FLAC 3D, and determined the optimal cutting path in combination with the actual situation in the mine [17].…”

Study on the Influence of In Situ Stress Distribution on the Stability of Roadway Surrounding Rock

“…In 1912, the concept of geostress was first proposed by Heim, a Swiss geologist [3]. It is pointed out that the rock is in a state of approximate hydrostatic pressure due to the rheological action for a long time under the continuous action of large stress [4][5][6]. e stress is equal to the gravity of the overlying rock mass, i.e., σ x � σ y � σ z � cH.…”