Development of multi-sensors fusion monitoring system for shaft wall deformation

Abstract

Ensuring shaft safety is crucial for underground coal mining. The prevailing method for monitoring shaft deformation involves manual measurements conducted regularly, necessitating numerous surveyors to descend into the shaft. This approach is laborious and time-consuming, and its reliance on human intervention significantly affects accuracy. An emerging alternative employs an enhanced laser slam scanner comprising laser ranging and inertial navigation angle measurement modules. The accuracy of the inertial navigation angle often requires refinement through laser point cloud registration to mitigate errors. However, existing research has not explored the utilization of a single inertial navigation sensor within a shaft, which potentially influences measurement outcomes. To investigate the impact of inertial navigation angle measurement errors from lidar scanners on shaft interior measurements and propose corresponding error reduction methods, this study developed a multisensor fusion system for monitoring shaft wall deformations. Three experiments were conducted to assess the accuracy of this monitoring system: a laboratory experiment, a simulated experiment, and a real shaft experiment. The results demonstrated that the maximum mean absolute errors (MAEs) in the laboratory and simulated shaft experiments were 0.06 cm and 0.30 cm, respectively, validating the reliability of the point cloud processing algorithm. In the real shaft experiment, the maximum MAE was 0.48 cm, confirming the measurement accuracy of the monitoring system. Compared to manual measurements, the system reduced the measurement time by 48% and streamlined the process from 12 to 3 steps. These findings highlight the monitoring system’s centimeter-level accuracy, efficiency in reducing measurement time, simplification of the measurement process, and elimination of the need for human entry into the shaft.