Synthesized modeling and active disturbance rejection control for the Leighton Chajnantor Telescope.

This article focuses on the development and evaluation of an active disturbance rejection controller (ADRC) for the pointing control system of the Leighton Chajnantor Telescope (LCT), a 10.4 m submillimeter telescope relocated from Hawaii to the Chajnantor Plateau in Chile. Due to stronger wind disturbances at the new site and the absence of a protective dome, the authors constructed a synthesized simulation model integrating mechanical dynamics, motor drive analog circuits, motor/reducer models, and wind disturbance to test ADRC’s performance. Simulation results demonstrate that ADRC significantly improves pointing and tracking accuracy under various wind speeds and observing modes compared to the existing proportional controller and a tuned PID controller, maintaining errors well below the required threshold of 1.65 arcseconds. The study suggests ADRC as a promising, model-free control method for robust telescope pointing under harsh environmental conditions, with plans for future implementation and testing on the actual LCT system.