Kinematic models and simulations for trajectory planning in the cutting of Spatially-Arbitrary crosssections by a robotic roadheader

In this study, a boom-type roadheader's mechanical composition was simplified into a kinematic chain composed of a series of linked translational or rotational joints, and a coordinate system was constructed for the spatial pose of the roadheaders. Homogeneous coordinate transformations and robot kinematics were used to construct a spatial pose matrix for the pose of a roadheader's body and cutting head relative to the geodetic coordinate system. The compressive breaking forces of a cutting head during vertical and rotary cutting of coal walls was analyzed, and the trajectory planning for the cutting of arbitrary crosssections was described in detail. In addition, simulations of the limits of a roadheader in the cutting of crosssections were performed. Underground roadheader cutting trajectories were measured via the pose measurement sensors installed on the roadheader to verify the accuracy of the mathematical modeling, and it was determined that cuttings performed using manually-operated levers were highly random and had lower levels of crosssection forming quality. Therefore, trajectory planning and simulations for actual coal mine roadways as well as field tests on an S-shaped bottom-up trajectory plan for automated cutting were performed. The results of these tests indicated that the maximum absolute error on both sides of a coal roadway that has a 4500 × 4000 mm crosssection was 65 mm, which corresponds to a maximum relative control error of 1.4%. Hence, the control system developed in this work was observed to exhibit accuracy and quality that satisfy requirements for cross sections in a coalmine's roadways, effective repeatability, and absence of cumulative deviations. Hence, the results of this research study are highly significant and are of value for practical applications.