A nonlinear PID control strategy for hard disk drive servosystems

A hard disk drive has been the primary medium for storing information on computers. Recent increases in the hard disk drive track density have placed stringent requirements on the control of head position relative to the track center during reading and writing. Numerous techniques have been proposed to improve the track seeking/following capacity but very few research works utilize the nonlinear Proportional-Integral-Derivative (PID) control schemes.;The aim of this study is to put forward a novel design of a nonlinear PID controller type based on carefully choosing nonlinear gains to enable reducing the settling time, minimizing overshoot and improving the required control effort during the functions of the read/write head positioning servomechanism. In the proposed controller, gains of the conventional PID controller are modified by adding nonlinear terms to them. These nonlinear terms are functions of error and its derivative.