Energy-Efficient Active Reflectors with Improved Mechanical Stability and Improved Thermal Performance
Controlling surface wavefront of apertures using a distributed array of actuators to mechanically correct the surface has been widely studied. Traditional active reflector systems require a sustained voltage profile which holds each actuator at a specific strain state to control the surface of the reflector. Each actuator, typically piezoelectric, draws a small amount of power under nominal operation. This power draw is small, but can complicate mission designs that depend on a cryogenic primary reflector surface. In this study we have extended the results of our previous work to include nonlinear piezoelectric actuation for active reflector systems. By deliberately operating in the nonlinear regime, it is possible to deform the actuators in such a way that the reflector surface maintains its corrected shape without sustained power. Demonstration of unpowered primary mirror wavefront control has positioned the technology as suitable for cryogenic/infrared systems. This report describes a nonlinear piezoelectric characterization campaign, and the associated nonlinear energy-efficient active reflector demonstration.