A mode switching controller for HDD

The servomechanism in hard disk drives is required to have a fast point-to-point motion and also a high precision positioning. Mode switching control (MSC) approaches are widely used to meet these requirements. This paper proposes a MSC that considers the effect of saturation into account and minimizes the abrupt change of controller at the moment of switching by appropriate initialization of the track-following controller. The switching instant and initial states of controller are obtained by solving a quadratic optimization problem. Simulation results show that the proposed method enables smooth mode switching and improves the settling time..