Short seeking by multi-rate digital controllers for computation saving with initial value adjustment

Multi-rate control has been proposed to reduce the real time computation in hard disk drive servo systems. It has been showed that computation can be saved greatly without performance degradation by using multi-rate controller for track following. This work proposes a novel method for short seeking control based on multi-rate track following control and initial value adjustment. This method, which utilizes the same multi-rate controller and same servo structure as track following, adjusts the initial values of the track following controller for short seeking. Real time computation is greatly saved in two aspects: firstly, computation is saved by multi-rate scheme; secondly, initial value adjustment of the feedback controller makes the use of the feed-forward controller and reference trajectory unnecessary. Simulation and experimental results verify the effectiveness of the proposed method.