Results of a calibrated open-loop controller for piston/tip/tilt positioning of a segmented deformable mirror are
presented. The controller is based on a fit of a 3rd-order polynomial that maps desired positions to the electrode voltages
that actuate the segments. In addition to mapping positions to voltages, the controller limits positions to within the
reachable space of the device. Experimental testing shows that over nearly the entire 5 &mgr;m of stroke and ±4 mrad of tip
and tilt operating range, the controller positions segments to better than 30 nm rms of surface-figure error.