ABSTRACT
A typical PZT bimorph actuator generates significantly larger displacements than a PZT stack, though at the expense o f smaller forces and lower bandwidth output. Specific output characteristics are highly dependent upon actuator geome try. A PZT bender actuator that measures approximately 5 cm in length by 2.5 cm wide by 0.5 m m thick (a typical geometry) can provide a zero-displacement force o f a couple o f hundred millinewtons, displacements on the order o f a couple o f millimeters, and has a (no load) bandwidth on the order o f tens o f Hertz. As is the case wi th stack actuators, the bimorph force decreases linearly wi th increasing stroke due to the elasticity o f the material. Also, bimorphs tend to exhibit more pronounced static hysteresis than do stack actuators. A comparison o f several pie zoelectric bending actuators is given in Kugel et al. [50]. Examples o f devices that utilize piezoelectric bimorph actuation are those by Chonan et al. [51], Ellis [52], Gaucher [53], Kanno and Okabe [54] and Seki [55].
