Thermal deformation compensation of a composite beam using piezoelectric actuators

Abstract

Maintaining the surface shape of precision structures such as spacecraft antennareflectors has been a challenging task. Surface errors are often introduced by thermaldistortions due to temperature differences. This paper presents numerical andexperimental results of active compensation of thermal deformation of a compositebeam using piezoelectric ceramic actuators. To generate thermal distortion of thecomposite beam, two film heaters are bonded to only one side of the beam usingthermally conductive materials. To correct thermal deformation caused by the filmheaters, 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 onthe other side of the beam. First, finite-element analyses are conducted withconsideration of the coupled effects of structural, electric and thermal fields onthe composite beam. These analyses include static coupled field modeling of thebeam deformation with PZT actuation, transient modeling of the beam underthermal loading, and static coupled field modeling of the composite beam withthermal distortion and simultaneous PZT actuation to correct this distortion.Then, experiments are conducted to study the thermal effect, the PZT actuationeffect and active thermal distortion compensation using PZT actuators with aproportional, integral and derivative feedback controller. Finite-element modeling andexperimental results agree well and demonstrate that the proposed method canactively perform structural shape control in the presence of thermal distortion.