OPTIMAL AND ROBUST CONTROLLER DESIGN FOR HARD DISK DRIVE SYSTEMS WITH DUAL ACTUATOR

Abstract

Disk drive serves as an important data-storage medium for data processing systems. The trend in data storage products is towards high capacity, fast access and portability. This results in closer track width, higher servo bandwidths, increasing demands on robustness and noise immunity. One way to achieve high positioning accuracy and hand width is to set up a dual-actuator positioning system. Dual-actuator refers to the fact that there is a small actuator mounted on a large conventional VCM actuator. Our object is aimed at developing a dual actuator control strategy that can be applied to read/write head actuation in magnetic and optical disk drives. In this thesis we presented a model for the dual-actuator. The correctness of the model has been verified by the experiment tests. Based on the identified two inputs and two outputs dual actuator system model, an observer-based controller has been designed. Our controller design was based on discrete-time H2 optimal control technique. The simulation result of the overall control system of our design turned out to be very successful and all design specifications were fully achieved, Currently, we are focussing on the implementation issues of our controller to the real actuator system. We are now doing the implementation of the overall control system using DSP application board, Of course there are many things needed to be taken care of in a real implementation, These would be our future tasks.