Actuated suspensions with enhanced dynamics for hard disk drives

This paper presents two novel designs of piezoelectric milli-actuators for secondary-stage head positioning. The designs are an inline-actuated suspension and a quad-morph actuated suspension, which use a piezoelectric plate and a piezoelectric quad-morph, respectively, to drive a parallel mechanism into lateral stroke. The inline design at elongated portion of a slender load beam is capable of enhancing the first torsional frequency; whereas, the quad-morph design at the extended base plate is capable of enhancing the first sway frequency. Both designs produce adequate lateral stroke. The proof of concepts was confirmed using finite-element simulation and experimental modal testing.