Mechanically reconfigurable reflector for future smart space antenna application

Smart space antennas with mechanically reconfigurable reflectors (MRRs) not only compensate for shape errors induced by distortions in the reflector but, depending on the purpose, also change the service coverage area on the ground with the reshaped reflector. Although several simulation studies regarding different types of MRRs have been performed in the past few years, MRR designs are few because of the difficulty in developing a reflector with the proper mechanical properties and actuators with sufficient drive capacity. Managing the array of actuators is also an issue, particularly in space applications. This paper presents a prototype of a MRR system that consists of a flexible reflector, an actuator array, and a servo controller. The reflector is a layered structure of simple construction with capability of flexible tailoring of its mechanical properties for reshaping. Piezoelectric inchworm actuators were developed, each with large driving stroke and load capacity. Thirteen actuators attached to the back of the reflector provide specified linear displacements that adjust the surface shape of the reflector. To reduce the overall size of the MRR prototype system and the operating power, a distributed time-sharing control strategy was designed to control the actuator array. For a given target shape, the actuation values of the array were optimized. The optimization algorithm and reconfiguration of the MRR prototype were validated in experiments where two different target shapes with extreme deformations and curvatures are specified.