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

Abstract

The Caltech Submillimeter Observatory telescope was completely disassembled in 2023 October and will be shipped from Hawaii, USA to the new site at Chajnantor Plateau, Chile in 2024, where it is expected to be refurbished and renamed the Leighton Chajnantor Telescope (LCT). Since the much stronger wind load at the new site will provide a great challenge for LCT’s realization of a higher pointing and tracking accuracy, an active disturbance rejection controller (ADRC) is designed for LCT’s pointing control system. Due to the unavailability of LCT during its relocation process, it is necessary to develop a testbed to verify the performance of ADRC by constructing a synthesized simulation model of LCT’s pointing control system, including a mechanical dynamics model of the antenna, an analog circuit model of the motor drive system, a mathematical model of the direct current motors and the reducers, and a wind disturbance model. On the testbed, ADRC undergoes simulations to verify its capability to eliminate the negative impact of strong wind disturbance on LCT’s pointing control performance. The simulation results show that ADRC can bring benefits in improving LCT’s pointing and tracking accuracy when facing strong wind disturbance.