The design of two degree of freedom compound controller for 110 m radio telescope
Abstract
Considering that the 110 m large radio telescope has the characteristics of big structural flexibility and low fundamental frequency, a two degree of freedom compound controller is proposed basing on the traditional servo control and considering the influence of subreflector’s support structure for pointing accuracy. The controller consists of both inner and outer loop. The outer loop is based on the GPI (Generalized Proportional Integral) robust controller to determine the servo reference instruction by the vibration of subreflector; the inner loop uses the output of outer loop as its reference to control the drive part through the LQG controller. With this scheme, the flexible vibration of the drive part and the subreflector’s support structure can be effectively suppressed simultaneously, thus improving the antenna’s pointing accuracy. The validity of proposed algorithm is verified by numerical simulation on the equivalent antenna model.
