Strategies for disturbance compensation at large telescopes

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Large ground-based astronomy is advancing in size, technology, and the complexity of astronomical questions, necessitating an integrated, interdisciplinary approach to develop sophisticated observing instruments. Control engineering plays a crucial role in enhancing the optical performance of these telescopes. As ground-based telescopes expand, the demands for optical alignment and detector quality have intensified, making diffraction-limited observations increasingly reliant on active and adaptive optics. These systems, particularly adaptive optics with deformable mirrors, are essential for correcting wavefront errors caused by atmospheric distortions. The classic adaptive optics control loop functions as a feedback system to mitigate atmospheric wavefront distortion effects on detector output. Enhancing the system's performance involves reducing the feedback load and improving disturbance rejection through disturbance feedforward techniques. This work centers on the design and analysis of accelerometer-based disturbance feedforward for the Large Binocular Telescope, detailing its application in observations with LBTI. It encompasses a mechanical model of the telescope's main mirrors, an optical model addressing relevant low-order effects on the focal plane, and a comparison of various estimation techniques to derive the mirror's position from accelerometer data.