MIMO Youla Parameterized Adaptive Aberration Correction Based on Magnetic Fluid Deformable Mirror for Liquid Mirror Telescope

The rotation of a liquid mirror telescope (LMT) can produce large wavefront aberrations which are unknown and time-varying. This article proposes a multiple input multiple output (MIMO) Youla (Q) parameterized adaptive regulation for aberrations correction in the wavefront for LMT using an adaptive optics system with a magnetic fluid deformable mirror (MFDM). This approach first constructs a Youla (Q) parameterized set of all stabilizing controllers which includes the design of a state-space feedback decoupling law to promote the compensation system as a diagonal system, and then tunes the Youla parameters online for eliminating the unknown and time-varying aberrations utilizing a MIMO recursive least squares algorithm. Finally, the effectiveness of the MIMO adaptive regulation has been experimentally validated on a test system consisting of a prototype LMT and an MFDM. The test results illustrate that the unknown and time-varying dynamic aberrations can be effectively attenuated by the proposed MIMO adaptive control approach.