Adaptive velocity estimation for disk drive head positioning

With the rapid increase of data areal density in disk drives, the need for more accurate position sensing and velocity estimation techniques for the disk drive head actuator emerges. This paper studies the application of velocity estimation methods for disk drive head positioning servo-mechanism with a focus on adaptive windowing velocity estimation. The adaptive windowing technique requires no prior knowledge of measurement noise and shows a better performance compared to conventional finite difference method and Kalman filtering technique. We have compared the performance of adaptive velocity estimation methods under study over a noisy position trajectory in terms of measures for error statistics and undesired shifting. The undesired shifting measure has been developed to reflect the estimation delay and outliers. The simulation results show the superiority of adaptive windowing velocity estimation to conventional methods.