中国科学院南京天文光学技术研究所机构知识库

We have developed a novel metrology system for precision XY measurements based on a concept developed originally in an industrial vision context by which USB cameras observe a target with a special dots pattern. The system has then been extended to Rx-Ry (tip-tilt), Z and Rz measurements by adding more cameras within a suitable configuration. The basic principle is described, first validated on a preliminary experimental implementation used for testing a new type of hexapod. We then illustrate the setup designed as calibration bench for hexapods used as positioning devices of the

secondary mirrors of astronomical telescopes. While work is still ongoing for improving this new metrology system, currently achieved performances are a stability of is ≤1 μm along linear degrees of freedom, respectively 0.5 arcsec for tip-tilt; absolute accuracy over ranges of a few millimeters is 5-10 μm , respectively arcsec; incremental accuracy is 2-3

μm, respectively 5 arcsec.