Position and orientation measurement technology for bolter miner body based on dual-screen visual target

Abstract

Aiming at the problem that it is difficult to achieve the real-time and accurate measurement of the bolter miner’s position and orientation during the excavation process in coal mines, which leads to the difficulty in achieving directional excavation, a guidance method for bolter miner based on dual-screen visual target is proposed. Using two vertically installed light-sensitive imaging screens to form the dual-screen visual target surfaces and the indication laser emitted by the laser instrument presents light spots on the front and rear target surfaces. Combining with the visual measurement, high-precision raster calibration and other technology are applied to establish the mapping relationship of the spot centroid between 2D-3D coordinates, which is used to form the point cloud data of the coordinates. Based on the principle of grid indexing, coordinate transformation and Euler angle solving, combining with the biaxial inclinometer at the bottom of target to obtain the bolter miner body’s real-time position and orientation, the key points’ horizontal/vertical deviations relative to the roadway axis are calculated, which can provide data support for deviation correction during the excavation process. The off-target problem of the system is analyzed by constructing a mathematical model. Meanwhile, the effectiveness of the guidance method is verified by building an experimental platform. The experimental results indicate that this method can achieve a precision measurement of six-degrees-of-freedom spatial pose for the machine body. When the measurement distance is 9 m, the repeatability measurement precision of the yaw angle is better than 0.01º and the error of absolute measurement is less than 0.05º. Within the measurement range of 15−40 m, which uses the total station and mining laser to set the planning line, the measurement errors of key points’ horizontal/vertical deviations are less than 5 mm and 15 mm, respectively. The guiding system developed based on this method has also been successfully applied to the underground roadway excavation in coal mine, which fully meets the requirements of underground roadway excavation and the positioning of the machine body’s key points. The error characteristic of the guiding method is independent of the test distance. Also, all optical measurement functions involved in the method are realized inside the target, which can effectively shield the influence of the underground complex environment for the measurement function, and greatly improve the capacity of anti-dust interference in field application

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