Hard disk drives have been acting as data storage medium for computers ever since 1955 as it continuosly working towards smaller device due to the increasing demand for portable devices such as laptop. Consequently, the head positioning will have a lower error tolerance and controller has to attain better development of servomechanism. This has given rise the need for disturbance rejection in hard disk drives. As a result, there are various control techniques to achieve better performance in hard disk drives.