Bucket Wheel Reclaimer Calibration

This paper presents a method to calibrate the extrinsic parameters of LIDARs mounted on a Bucket Wheel Reclaimer (BWR). BWR's are widely used for stacking and reclaiming bulk materials in stockyards. Current BWR systems are either manually operated, remotely operated or semiautomated using the real-time point cloud data generated by one or more LIDARs. Accurate calibration is of crucial importance as the accuracy of the Earth frame point cloud data depends on it. Automated calibration is also a pre-requisite for fully autonomous BWR control. Calibration of BWR systems are more difficult than many other LIDAR systems because of their limited pose variation capabilities and the environmental constraints of stockyards. This paper analyzes the problem, presents observability conditions, presents a method to estimate the calibration parameters and discusses the challenges involved with BWR systems. The results demonstrate subdecimeter accuracy.