Analytical Modeling and Implementation of an Imaging Cantilever With a Thermoplastic Stiffener

Piezoelectric (PZT) tube actuators have been widely used in miniature resonant scanning systems due to their low operation voltage and high-frequency bandwidth. Although several designs of asymmetric stiffeners have been implemented to mitigate the inherent parasitic deflection of PZT actuators, to the best of the authors' knowledge, finite element analysis (FEA) has only been used to predict the harmonic response of asymmetric fiber cantilevers. This study presents the analytical modeling of an arbitrary-shaped resonant fiber cantilever based on Castigliano's and Rayleigh-Ritz's methods. The proposed model is designed to quickly identify and adjust the influential variables of asymmetric stiffeners, comparable to FEA in terms of its high prediction accuracy and fewer numerical computations. In addition, a thermoplastic polystyrene sheet was adopted to fabricate the asymmetric stiffener due to its sufficient stiffness, low cost, and high fabrication repeatability. The proposed model could accurately predict frequency separation at various fabrication tolerances, with the most significant errors from the experiments of 3.21%, comparable to FEA prediction results of 3.00%. Imaging results were acquired from an ex-vivo rat's stomach and small intestine using the implemented asymmetric fiber cantilever and compared with their histological images.