In a typical disk drive servo system, two or more types of controllers are used for track seeking, track following, and track settling modes. This leads to the problem of mode switching among these controllers. We present in this paper a unified control scheme, the discrete-time composite nonlinear feedback control, which can perform all the above functions in hard disk drive (HDD) servo system...

The precise mechanism of the tremor in Parkinson's disease remains a subject for debate and investigation. The number of conflicting views in the standard clinical and physiological texts and journals attests to the difficulty of the problem. Some investigators suggest that central structures are 'released' to periodic discharge (Brain, 1960; Holmes, 1952; Bucy, 1944; Merritt, 1959). Others vie...

The design of optimal disturbance accommodation and servomechanism controllers with limited plant model information is considered in this paper. Their closed-loop performance are compared using a performance metric called competitive ratio which is the worst-case ratio of the cost of a given control design strategy to the cost of the optimal control design with full model information. It was re...

That speech is the most highly developed motor skill possessed by all of us is a truism, but how is this truism to be understood? Al though the investigation of speech production and motor behavior have proceeded largely independently of each other, they are alike in sharing certain conceptions of how skilled movements are organized. Thus, regardless of whether one refers to movement in general...