Study on control strategies for an antenna servo system on a carrier under large disturbance

Abstract

In this paper, control strategies and vibration isolation methods are investigated in order to enhance the attitude control accuracy of an antenna servo system on a carrier under large disturbance. First, the multi-body dynamical equations of the antenna servo system on a carrier incorporated with six wire-cable vibration isolators are derived. Then, an improved adaptive variable-rated exponential reaching law is proposed, and the non-singular terminal sliding mode control is designed based on the nonlinear multi-body model. Finally, simulations are carried out and results show that excellent control accuracies for both the azimuth and the pitch of the antenna can be achieved by the proposed control method, specifically with a shorten reaching time in the cases of holding a fixed angle and tracking a sinusoidal motion that is better than the existing adaptive variable-rated exponential reaching law. Furthermore, the six wire-cable vibration isolators with hysteretic characteristics of restoring forces are adopted that can effectively isolate the large disturbance transmitted from the carrier to the antenna servo system and are shown to be able to further improve the attitude control accuracy.