Title of Presentation: High-Precision Adaptive Control of Large Antenna Surface

Primary (Corresponding) Author: Houfei Fang / Ubaldo Quijano

Organization of Primary Author: Jet Propulsion Lab

Co-Authors: Eastwood Im, Ubaldo Quijano, Kon-Well Wang, Jeff Hill, Jim Moore, Changgeng Lui and Frank Djuth

Abstract: Under NASAís Earth Science Technology Program, a novel high-precision adaptive control architecture and the associated component technologies are being developed for large antenna surface. A large and high-precision antenna implies high RF frequency and high resolution, which is greatly demanded by earth science mission planners and gives them the flexibility in choosing of orbits such as LEO, MEO and GEO. It can be employed by radar and radiometer to monitor resources, weather and to perform hazard assessment. Due to the large size (from several meters to several tens of meters), the antenna needs to be deployable to accommodate the fairing size of a launch vehicle and to be light-weight. However, how to maintain the surface figure accuracy of a large deployable antenna is extremely challenging.

The architecture of the high-precision surface control system consists of a large deployable reflector, a set of flexible actuators (mounted on the back of the antenna reflector), a wavefront sensing metrology subsystem, and an active (feedback) controller. The metrology subsystem periodically measures the surface contour and sends the information to the controller. Guided by shape control laws, the controller updates voltage signals to control the actuator strain at various antenna positions to maintain the desired shape contour. This paper will discuss the technologies of all the components of this architecture which include the Flexible PVDF Film actuator, wavefront sensing metrology, analytical modeling of the system and active shape control laws.