Co-focus control of segmented primary mirror telescopes based on segmented mirror pose detection

A method for the co-focus closed-loop control of segmented primary mirrors in astronomical telescopes is proposed based on pose detection. The pose changes of each segment relative to a reference segment are calculated by constructing a pose estimation matrix. Subsequently, the required actuation values for each segment are computed using the pose-to-actuation mapping matrix. The parameter analysis evaluates the noise characteristics of a system composed of four segmented mirrors. Experimental validation on a four-segment subsystem of the LAMOST primary mirror Mb demonstrates that the proposed co-focusing control method can converge the system focal spot to within 0.1 arcsec even under temperature variations exceeding 12°C, and thus enables the long-term confocal maintenance during continuous operation.