Numerical Investigation of the Response of Active Bend-Twist PZT Actuator

Army combat operations have placed a high premium on reconnaissance missions for micro air vehicles (MAVs). An analysis of insect flight indicates that in addition to the bending excitation (flapping), simultaneous excitation of the twisting degree-of-freedom is required to manipulate the control surface adequately. By adding a layer of angled piezoelectric segments to a Pb(Zr,Ti)O3 (also referred to as PZT) bimorph actuator, a bend-twist coupling may be introduced to the flexural response of the layered PZT, thereby creating a biaxial actuator capable of driving wing oscillation in flapping wing MAVs. The present study presents numerical investigation of the response of functionally–modified bimorph designs intended for active bend-twist actuation of cm-scale flapping wing devices. The relationships of geometry and orientation of the angled segments with bimorph bend-twist response will be presented using results of finite-element analyses.

Active Bend-Twist PZT Actuator for Centimeter-Scale Flapping Wing Micro-Air Vehicle

The present study focuses on development of a flapping wing micro-air vehicle (FWMAV) that employs a piezoelectric actuator to drive the leading edge of the wing. An analysis of insect flight indicates that in addition to the bending excitation (flapping), simultaneous excitation of the twisting degree-of-freedom is required to adequately manipulate the control surface. A functionally-modified piezoelectric bimorph composed of Pb(Zr0.55Ti0.45)O3 (PZT) is being used to produce two degree-of-freedom motion, namely the flapping and twisting facilitated by an off-axis layer of piezoelectric segments affixed to the top surface of a traditional bimorph actuator. The modification of the top surface of a traditional PZT bimorph actuator introduces active bend-twist coupling to the flexural response of the resulting layered PZT. This paper presents analytical and experimental investigation of functionally-modified bimorph designs intended for active bend-twist actuation of cm-scale flapping wing devices.