Proposing a Pretwisted Bimorph Actuator

Though only small strains are available in piezoceramic materials, bending actuators provide reasonable deflections. Due to beam kinematics bending actuators usually are slender beams having flat cross-sections. This feature allows for maximum deflection in one direction. However, the axis orthogonal to it usually is not actuated. Instead of combining two straight bending actuators to overcome this problem we propose a bending actuator which is pretwisted. Controlling the pretwisted actuator segment-wise provides bending in several independent directions as well.

Investigated is a pretwisted bimorph, similar to a helicoid. The active elements along the beam axis are subdivided and controlled separately, hence allowing independent control of the curvature of each section. Herein we give a first characterization of the pretwisted bimorph actuator. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)