<title>Thermal deformation compensation of a composite beam using piezoelectric actuators</title>

Abstract

Maintaining surface shape of precision structures such as spacecraft antenna reflectors has been a challenging task. The surface errors are often introduced by thermal distortions due to temperature differences. This paper presents numerical and experimental results of active compensation of thermal deformation of a composite beam using piezoelectric ceramic actuators. To generate thermal distortion to the composite beam, two film heaters are bonded to only one-side of the beam using thermally conductive materials. To correct thermal deformation caused by the film heaters, PZT (Lead Zirconate Titanate), a type of a piezoelectric ceramic material, is used in the form of patches as actuators. These PZT patches are bonded on the other side of the beam. First, finite element analyses are conducted with the consideration of the coupled effects of structural, electric, and thermal fields on the composite beam. These analyses include static coupled field modeling of the beam deformation with PZT actuation, transient modeling of the beam under thermal loading, and static coupled field modeling of the composite beam with thermal distortion and simultaneous PZT actuation to correct this distortion. Then, experiments are conducted to study thermal effect, PZT actuation effect and active thermal distortion compensation using PZT actuators with a Proportional, Integral, and Derivative (PID) feedback controller. FEM and experimental results agree well and demonstrate the proposed method can actively perform structural shape control in the presence of thermal distortion.