Design and study of visual fast detecting instrument for fiber positioners

摘要

The fiber positioner is the core component of the multi-object spectral survey telescope. Its precise scanning plays a key role in the observation of the astrology. The eccentric bracket is an important part of the fiber positioner in LAMOST. To ensure the installed accuracy of the fiber positioner, a visual detecting instrument is designed for quick and accurate measurement of critical dimensions. Using two orthogonally placed cameras, the distances between the spatial intersecting shafts of the complex eccentric bracket are precisely detected. The position of the circular hole in the image is extracted by Hough Transform. However, the accuracy of this method is not high after experiments. An active luminous target was designed, manufactured and installed on the eccentric bracket. Finally, according to the experimental data, it is shown that the measurement of the instrument can meet the installed accuracy of the fiber positioner and improve the measuring efficiency.