13 January 1992 PAMELA: control of a segmented mirror via wavefront tilt and segment piston sensing
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A hardware demonstration of segmented mirror systems for adaptive optics is described. The basis of the phased array mirror extendible large aperture (PAMELATM) concept is that large adaptive mirrors can be fabricated from many small segments by utilizing edge-sensors, which measure the piston error between segments. We have investigated the interaction between the piston and tilt control loops which direct the motion of individual segments. The segment tilt, which is set by a wavefront-sensor-based control loop, directly affects the piston error between segments; therefore, the segment piston control loop must be able to perform corrections much faster than the rate at which the tilt corrections are being performed. In this experiment, we have one fully actuated segment with a wavefront sensor measuring the error in the wavefront gradient. An adjacent segment is driven in piston to produce the piston error signal. We measure and present the bandwidth trade-offs between the two control loops and predict how this will affect the performance of larger systems. This interactive control loop methodology has an advantage over normal adaptive optics systems in that the computationally intensive wavefront reconstruction process can be removed due to the direct measurement of both the tilt and the piston errors.
© (1992) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Anthony D. Gleckler, David J. Markason, and Gregory H. Ames "PAMELA: control of a segmented mirror via wavefront tilt and segment piston sensing", Proc. SPIE 1543, Active and Adaptive Optical Components, (13 January 1992); doi: 10.1117/12.51180; https://doi.org/10.1117/12.51180


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