Modeling And Control Of A Dual-stage HDD Head Positioning Servo System

A dual-stage actuator (DSA) system in a hard disk drive (HDD) is expected tomeet the servo bandwidth requirement for higher recording density in the near future.However, because of the existence of flexible modes in the system, how to designreasonable controller is a challenge that needs to be addressed. In order to simplify thecontrol design, existing work on the DSA track seeking control is usually based on therigid model, which lead to large tracking errors, reduce the system performance.Therefore, this paper proposes a high-order nonsingular terminal sliding mode(NTSM) control scheme to suppress the undesirable flexible vibration, as well as toimprove the head positioning speed and accuracy, firstly flexible model of the system isbuild, then the flexible DSA system is decomposed into an input-output subsystem andan internal subsystem, in order to design the NTSM controller. On this basis, in orderto effectively suppress chattering, a three-order NTSM control method is proposed forthe input-output subsystem, the control input signal is obtained by low-pass filtering tosuppress chattering.Matlab/Simulink is used to get the simulation results which show that the settlingtime in track seeking is reduced and the tracking precision is improved with theproposed method.