Design and implementation of a hard disk drive servo system using robust and perfect tracking approach

We tackle the problem of a servo system design for a conventional hard disk drive with a single voice-coil-motor (VCM) actuator using the so-called robust and perfect tracking (RPT) approach. We first model the physical system and then formulate it into a robust and perfect tracking problem, in which a measurement feedback controller can be obtained to achieve a robust and perfect tracking for any step reference in the presence of external disturbances and arbitrarily initial conditions. Some trade-offs are then made in order for the RPT controller to be implementable using existing hardware setup. The implementation results of the RPT controller are compared with those of a PID controller. The results show that the servo system with our RPT controller has much better performances than the PID one has. It has faster settling time, lower overshoots and higher accuracy