Research on Wind-Disturbance Suppression Control for Large Radio Telescope Servo System

Wind loads acting on a radio telescope antenna structure reduce the antenna's pointing accuracy and have become a serious problem with the high-accuracy pointing of a large aperture antenna. Research on compensation for wind-disturbance effect on the servo system to improve beam-pointing accuracy is very important. This paper analyzes the effect mechanism of wind disturbance on the antenna servo system and establishes a 4DOF model from the input current signal of the motor and wind-induced torque to angular displacements for the antenna azimuthal system. Then two double-loop active disturbance-suppression controllers based on disturbance observer-based control (DOBC) and active disturbance rejection control (ADRC) are designed, respectively. The validity and superiority of the proposed design scheme are verified on a 100m class antenna model. Compared with a PI controller designed by quantitative feedback theory (QFT), both active disturbance suppression schemes can obtain better dynamic response performance and rejection of external wind disturbances. In particular, compared with the robust PI controller, our simulations revealed that the maximum and RMS disturbance responses of the ADRC are reduced by half, and the response time is shortened by 20 seconds.