Digital servo control of a novel disk actuator

A novel disk actuator transported on parallel flexures is considered for digital servo control. The control scheme derives the state estimates from a position error signal which resembles a sawtooth wave form. The estimator is based on a second-order actuator model with two augmented states for both track-following and track-access modes. The structure of the track-following controller is of a proportional-integral-derivative type. The estimator´s residue time history shows that the algorithms are sufficiently robust to accommodate the model uncertainty, measurement noise, and force disturbance that are associated with a disk drive mechanism. The performance characteristics of the actuator are presented in terms of transfer functions, a step input response, a track misregistration probability distribution function, and 1/3 stroke seek dynamics