SERVO SIGNAL QUALITY AND DUAL-STAGE ACTUATOR SYSTEM FOR MICRON TRACKWIDTH

An algorithm to design servo systems for future magnetic disk drives has been developed. An optimal relationship between the trackwidth and the servo bandwidth of a magnetic disk drive which minimizes the limit signal S/N ratio is proposed which takes into account position signal noise and mechanical vibrations. The idea of required accuracy distribution is introduced. A dual-stage actuator with a single-input single-output (SISO) system is used to confirm the calculated results. This paper describes a method for obtaining the desired servo signal quality and introduces a relationship between trackwidth and servo performance that can make it possible to design head positioning systems for trackwidths under one micron.