Advanced piezoelectric single crystal based actuators

Abstract

TRS is developing new actuators based on single crystal piezoelectric materials such as Pb(Zn_1/3Nb_2/3)_1-xTi_xO₃ (PZN-PT) and Pb(Mg_1/3Nb_2/3)_x-1Ti_xO₃ (PMN-PT) which exhibit very high piezoelectric coefficients (d₃₃ = 1800-2200 pC/N) and electromechanical coupling factors (k₃₃ > 0.9), respectively, for a variety of applications, including active vibration damping, active flow control, high precision positioning, ultrasonic motors, deformable mirrors, and adaptive optics. The d₃₂ cut crystal plate actuators showed d₃₂ ~ -1600 pC/N, inter-digital electroded (IDE) plate actuators showed effective d₃₃ ~ 1100 pC/N. Single crystal stack actuators with stroke of 10 μm-100 μm were developed and tested at both room temperature and cryogenic temperatures. Flextensional single crystal piezoelectric actuators with either stack driver or plate driver were developed with stroke 70 μm - > 250 μm. For large stroke cryogenic actuation (> 1mm), a single crystal piezomotor was developed and tested at temperature of 77 K-300K and stroke of > 10mm and step resolution of 20 nm were achieved. In order to demonstrate the significance of developed single crystal actuators, modeling on single crystal piezoelectric deformable mirrors and helicopter flap control using single crystal actuators were conducted and the modeling results show that more than 20 wavelength wavefront error could be corrected by using the single crystal deformable mirrors and +/- 5.8 ° flap deflection will be obtained for a 36" flap using single crystal stack actuators.