This paper presents the derivation, implementation, and testing of an improved point spread function (PSF) reconstruction technique for the University of Victoria's dual-deformable-mirror (DM) woofer-tweeter (W/T) adaptive optics (AO) system. The methodology has been tested on numerical models and implemented on an experimental dual-DM AO system. The methodology is based on the data saved by the AO system during the science exposure. These data are later used in the postprocessing stage to reconstruct the PSF. Although the results are unique to the present W/T AO bench, the proposed PSF reconstruction methodology will be applicable to other dual-DM systems and to multi-DM AO systems.
The Woofer-Tweeter experiment started in the Adaptive Optics Laboratory of the University of Victoria in February 2005 has recently achieved completion. The goal of this experiment is to validate the woofer-tweeter AO concept i.e. instead to have a single deformable mirror conjugated at the ground, two DMs conjugated at the ground are used to achieve both the necessary stroke and actuators density required for a single DM for an ELT. Recently, the loop has been closed on the turbulence with a loop rate of 100Hz. Two closed-loop controllers have been tested so far: a global integrator and a tweeter off-loading integrator. This paper describes the UVic Woofer-Tweeter bench layout and components and the Woofer-Tweeter simulation tool used to both model and control the experiment. A glimpse on the very first results from the closed-loop operations is also given.
This paper describes the control of two deformable mirrors (DM) and a tip tilt mirror for adaptive optics. The purpose of this experimental adaptive optics system at the University of Victoria is to prove the Woofer Tweeter concept for use in instruments for the Thirty Meter Telescope (TMT) which is currently under development. The first deformable mirror is a large stroke DM (Woofer) capable of lower frequency correction in both the temporal and spatial domains. The other DM (Tweeter) is capable of the high temporal and spatial frequency corrections of the turbulence. The response speed of the Woofer is incorporated into the Tweeter controller in order to allow for appropriate offloading from the Tweeter to the Woofer. In order to determine which Tweeter shapes must compensate for the slower Woofer and which are not coupled to the Woofer, the cross correlation of the devices is determined. The method of converting the wave front sensor (WFS) measurements to control signal error is given. The transfer functions of the controller are provided, along with rejection ratio plots, bandwidths and amplitude response to system noise.
In this paper, we provide an overview of the adaptive optics (AO) program for the Thirty Meter Telescope (TMT) project, including an update on requirements; the philosophical approach to developing an overall AO system architecture; the recently completed conceptual designs for facility and instrument AO systems; anticipated first light capabilities and upgrade options; and the hardware, software, and controls interfaces with the remainder of the observatory. Supporting work in AO component development, lab and field tests, and simulation and analysis is also discussed. Further detail on all of these subjects may be found in additional papers in this conference.
This paper describes the current control system of the multi-conjugate adaptive optics (MCAO) test bench system that is being developed at the University of Victoria, BC, Canada. The design and analysis of a control system for an AO system employing a Micro-Electro-Mechanical-System (MEMS) based deformable mirror and a PI tilt mirror is presented. This paper focuses on modal control of one deformable mirror and a tilt mirror with a Shack-Hartmann wave front sensor. Diagrams of how all the components work together as a control system are given. Bandwidth measurements for a single delay integrator controller and for a matched delay integrator are presented. Analysis shows that matching the delays of the integrator to the delays of the optical feedback loop provides considerable improvement in bandwidth.
This paper describes the current control system of the multi-conjugate adaptive optics (MCAO) test bench system that is being developed at the University of Victoria, BC, Canada. The design and analysis of a control system for an AO system employing a Micro-Electro-Mechanical-System (MEMS) based deformable mirror is presented. The AO system is part of a larger test bed that is a scale version of an 8-meter telescope. This paper focuses on the control of one deformable mirror with a Shack-Hartmann wave front sensor. Diagrams of how all the components work together as a control system are given. A conversion from actuator signal space to Zernike mode coefficients is presented. Analysis shows that this control system is capable of reducing low frequency aberrations. Shortcomings of the system error rejection are discussed. The steady state and step response to tilt simulated on the wave front sensor is shown.
In this paper, we describe the progress of the construction of the Multi-Conjugate Adaptive Optics laboratory test-bed at the University of Victoria, Canada. The test-bench will be used to support research in the performance of multi-conjugate adaptive optics, turbulence simulators, laser guide stars and miniaturizing adaptive optics. The main components of the test-bed include two micro-machined deformable mirrors, a tip-tilt mirror, four wavefront sensors, a source simulator, a dual-layer turbulence simulator, as well as computational and control hardware. The paper describes changes in the opto-mechanical design, characteristics of the hot-air turbulence generator, performance achievements with the tip-tilt and MEMS deformable mirrors as well as the design and performance of the wavefront sensors and control software.