Integrated Modeling of a Laboratory Setup for a Large Deformable Mirror

Abstract:
We study a concept for a low-cost, large deformable mirror for an Extremely Large Telescope. The use of inexpensive voice-coil actuators leads to a poorly damped faceplate, with many modes within the desired control bandwidth. A control architecture, including rate and position feedback to add damping and stiffness, for the faceplate has been presented in our previous papers. An innovative local control scheme which decouples adjacent actuators and suppresses low-order eigenmodes is a key feature in our controller. Here, we present an integrated model of a partially illuminated large deformable mirror in an experimental laboratory setup with a limited amount of actuators. From the model, conclusions are drawn regarding the number of actuators needed to identify the key features, such as local control performance, dynamic range, and controllability and robustness of the deformable mirror.