Composite Laminate Characterization and Piezoelectric Actuator Testing for the Design of a Precision, Adaptive, High-Strain Composite Hinge
Michael A. Echter
Monday, March 27, 2017
The DISCIT (Deployable In-Space Coherent Imaging Telescope) research effort at MIT Lincoln Laboratory seeks to develop a 0.7 m diameter deployable sparse-aperture primary-mirror telescope that leverages advances in high-strain composite deployable structures and piezoelectric actuation technologies. A system such as DISCIT could provide affordable, high-resolution, persistent space-based imaging in a low-SWaP (size, weight, and power) design over existing technologies. A key challenge with deploying a sparsely filled primary in an imaging telescope is the precision required to collocate the mirror segments relative to the other optical components. DISCIT addresses this in two ways: (1) the primary mirror segments are deployed and coarsely positioned using flexible composite hinges to achieve better than ±10 µm piston and axial positional repeatability and ±100 µrad pitch and roll angular repeatability, and (2) the mirror segments are then phased using piezoelectric actuators that accomplish the final precision alignment of the optical system. Therefore, the composite hinges only need positional and angular repeatability within the capture range of the piezoelectric actuators. This proposal focuses on the selection of the piezoelectric actuators and the development of the flexible composite hinges used to deploy the primary mirror segments, including materials testing for the elastic properties of the laminate being used and measurements of the positional and angular repeatability of a candidate hinge selected for future experiments. A novel, precision, adaptive, high-strain composite hinge design will be proposed that incorporates piezoelectric patch actuators bonded to the laminates on the characterized candidate hinge to enable a low-SWaP design for multi-DOF active alignment of the primary mirror segments.