Study on wind disturbance rejection and compensation methods for servo control of large-aperture radio telescopes

With the development of large-aperture radio telescopes, wind-induced pointing errors have become one of the key factors limiting their performance. Traditional PID control strategies exhibit limitations in suppressing transient wind disturbances and are prone to exciting structural vibrations. Therefore, this paper proposes a composite servo control compensation method for large-aperture radio telescopes, which combines Terminal Sliding Mode Control (TSMC) and an Extended State Observer (ESO). First, by establishing a rigid-flexible coupling model of the radio telescope structure, the mechanism of wind-induced pointing errors is analyzed. Second, the proposed ESO is used to estimate and compensate for the system’s lumped disturbances in real time, while TSMC ensures the convergence of the system states within a finite time through its sliding mode control mechanism, thereby significantly enhancing the system’s robustness and disturbance rejection capability. Finally, the proposed method is validated using the QTT 110-m radio telescope as a case study. Simulations demonstrate that the TSMC+ESO method reduces the pointing error to 2.0088″, achieving an approximately 13-fold improvement compared to PID control (26.964″) and significantly outperforming traditional methods. The results indicate that, compared to traditional PID control, this composite control method can effectively suppress pointing errors caused by transient wind disturbances, substantially improving the pointing accuracy and stability of the telescope under such conditions.