Event-triggered optimal reset control of hard disk drive head-positioning servo systems

This article proposes a state-feedback-based optimal law with reset control for two typical kinds of head-positioning systems with nonlinearities of hard disk drives which combine the improved event-triggering reset condition and an optimal reset law design problem. First, a reset control law is proposed to reset the state of the system at the instants or some reset surfaces which have been proved can overcome the linear limitations. The reset surface is considered as a function of event or it can be defined as an event-triggered system, in which some states of the controller are subjected to impulsive actions. Second, a model predictive optimal law is proposed to the design of the after-reset value which was finally calculated through series linear matrix inequalities. Finally, in comparison with recent linear or nonlinear control methods applied to hard disk drives, our proposed approach shows the simplicity in design process and the robustness to nonlinear uncertainties in plant.