Feedback control design of servo systems:a review

Servo systems have been widely used in various fields of industry and defense,such as radio telescope antenna servo systems,radar servo systems,‘communication on the move' servo systems,hard disk drive servo systems,metal cutting systems,digital control machines and so on.To meet high demands on the performances of servo systems,many research efforts have been devoted to advanced control design for servo systems.This paper gives a brief review of the existing achievements in control design for servo systems,with antenna servo systems and hard disk drive servo systems taken as examples to explain several issues in this area; such as,the high-frequency resonance,the bandwidth constraint,the external disturbance and so on.Particularly the disturbance rejection,the optimal tracking control and the robust stabilization are discussed in more details.