Characterization of Multilayer Piezoelectric Stacks Down to 100K

Abstract

A variety of applications require precision control at cryogenic temperatures. The next-generation of telescopes are looking to increase apertures in space telescopes and observations in the mid through far infrared regions enabling new science ranging from exoplanet characterization to precision astronomical observations to further refine astrophysics models. Concepts include segmented telescopes which are capable of observations in UV through IR bands, thus driving the need for UV surface performance at cryogenic temperatures. These telescope’s segments will require actuators for controlled surface displacements capable of operation at cryogenic temperatures ( $\le 150\text{K}$ ). The work reported in this paper is directed at understanding piezoelectric stack actuator operation down to cryogenic temperatures (100 K) which will provide actuator designers the needed information to model and predict performance. The data reported down to 100 K includes; resonance data, displacement voltage (S vs E) and capacitor voltage (D vs E) curves, stiffness, hysteresis, blocking force, DC resistance measurements, thermal strains and the coefficients of thermal expansion as a function of the electrical boundary conditions. Open-loop control drive strategies and errors are also reported. We apply this data to a surface parallel actuator mirror design.