Abstract: A dual stage actuator (DSA) suspension has a single microactuator such as a PZT element on one side of central longitudinal axis of the suspension, and a pseudo symmetry structure formed or affixed on the other side of the central longitudinal axis opposite the PZT. The pseudo symmetry structure has mass and stiffness that mirrors the PZT, thus keeping the suspension mechanically balanced and symmetric about the longitudinal axis for improved suspension performance especially in a shock environment.

Abstract: For controlling 1st and 2nd torsion characteristics in a disk drive suspension, a disk drive suspension is provided having a beam portion with edge rails extending along its edge regions, the edge rails are locally varied substantially identically between lesser and greater heights along their lengths, the beam portion having a central region increasingly extending above or below the plane of excitation in inverse response to the edge rails increasingly or decreasingly extending above the plane of excitation. The inverse relation of the beam portion central region and the rail heights relative to the plane of excitation tends to offset in at least part changes in the balance of the suspension upper and lower inertia components from changes in the geometry of said suspension.