Design of a preload device for PZT actuator using permanent magnets

Piezoelectric actuators must be preloaded to prevent damage due to tensile loading. Spring-preloaded actuators sacrifice some of the total stroke of the actuator. The authors propose a preload device using permanent magnets. By employing magnetic preload, the static performance of the actuator is improved, while increasing the total stroke. The proposed preload device decouples the lateral motion of the actuator from the actuating direction, thus eliminating the need for a complex flexure hinge mechanism.