Robust Linear Quadratic Sliding-Mode Control for Hard Disk Drives

In this paper, we design a robust servo controller for hard disk drives in track-following mode. To follow the target track center accurately under the effects of system uncertainties and various external disturbances, we propose a robust sliding-mode control with a new switching surface. To reduce the chattering effect, the augmented system adopts two auxiliary states (i.e., state estimates and control input differential), as suggested in this paper. Simulation results show that the chattering effect is reduced with the use of the proposed sliding-mode control to the augmented state system. The performance evaluation with time maximum disturbance shows an improved robustness and stability of the augmented system