Discrete-time closed-form solution of time-optimal seek control for hard disk drives

This paper derives a discrete-time closed-form solution of time-optimal seek control based on the 3rd-order hard disk drive model including the back-EMF effect and coil inductance. Using the proposed method, online reference signal generation for 2-DOF control structure is discussed for short and long seeking cases. Simulation results show that the reference signals generated are good for smooth settling. Modification of the proposed method for improving acoustics during seeking is demonstrated. A feasible implementation of the proposed method is investigated for efficient usage of digital signal processor and limited memory available. The feed-forward current for seek control is obtained considering the power amplifier saturation so the proposed method has better features of adaptation for varying operating conditions.