Application of Stereo-Depth Camera and Alignment Algorithms for Part Monitoring During Machining

Abstract

A stereo-depth camera is proposed to be used in conjunction with fiducial markers on a calibration plate and a fine-tuning alignment algorithm for part monitoring in a CNC machine. Together, a selected pyramid-shaped part within the machine could be monitored. The position, orientation, geometry and surfaces of the pyramid part are measured and compared with the pyramid’s desired model. This system can monitor the position and geometry within 1mm of accuracy, orientation within 1 degree of accuracy, and surface fitting within 2mm of accuracy, which closely aligns with the advertised accuracy of the stereo depth camera. While the accuracy is not enough to be confident if the part was machined to an industrial tolerance for most machined parts, this accuracy is sufficient to show that a part roughly matches the position and expected geometry of the model. This information allows the machine to monitor for any significant interference or interruptions during and after machining.