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

This paper deals with the problem of a servo system design for a convention al hard disk drive with a single voice-coil-motor (VCM) actuator using a so -called robust and perfect tracking (RPT) approach, We will first model the physical system and then formulate it into a robust and perfect tracking p roblem, in which a measurement feedback controller can be obtained to achie ve a robust and perfect tracking for any step reference, i.e., the L-p-norm of the resulting tracking error,vith 1 less than or equal to p < <infinity > can be made arbitrarily small in the presence of external disturbances an d initial conditions. Some tradeoffs are then made in order for the RPT con troller to be implementable using the existing hardware setup. The implemen tation results of the RPT controller are compared with those of a proportio nal integral derivative (PID) controller The results show that the servo sy stem with our RPT controller has much better performance than the PID one h as. Our servo system has faster settling time, lower overshoot and higher a ccuracy.