An adaptive velocity estimation approach for improved disk drive control performance

For disk servo system design, it is desired to optimize data storage and transfer subject to the constraints imposed by the servomechanism including velocity estimation and control algorithm, disk space, the actuator, and other limiting factors. Therefore, positioning the head with high accuracy, speed, and reliability is of significant importance. Since velocity estimation is essential for many disk servomechanisms, the quality of head positioning will be governed by the accuracy, speed and reliability of the velocity estimation methods employed. In this paper, adaptive windowing techniques for discrete velocity estimation in disk drives are introduced. The methods are compared with conventional techniques such as finite difference method and Kalman filtering using the introduced measures. It is shown that the proposed techniques generate relatively accurate and reliable estimates with reduced time delays and lower amplitude distortions when compared with the previous methods. Finally, it is demonstrated that the proposed techniques improve the control performance of the disk servo systems.