Design and optimization of a dual-stage high bandwidth piggy-back electromagnetic milli-actuator

A novel high bandwidth secondary-stage milli-sized electromagnetic actuator is proposed and reported. It is constructed at the tip of the carriage arm of a conventional actuator system. The electromagnetic characteristics and dynamic performance of the piggy-back milli-actuator were investigated and are reported. The study shows that the head positioning system supported by the proposed dual-stage milli-electromagnetic actuator has achieved high primary resonances, lateral rigid body mode at 18 kHz and torsional mode at 25 kHz, and can have a significantly wide servo bandwidth.