23 June 1994 Primary mirror controller with digital error correction
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A dither mirror has been developed which uses three piezo-electric translators for mirror positioning. Three voltages, generated by a strain gauge in each translator and proportional to translator position, are used as position feedback in the closed-loop controller. The nominal mirror scan pattern, a 33 Hz square, is produced by commanding azimuth and elevation angles. This paper describes the three-channel electronic controller under development. Each channel is a closed-loop controller for one actuator/strain gauge pair. Controller circuitry is described and the results of bandwidth optimization are presented. Controller performance is further enhanced through the application of a Digital Error Correction System (DECS). DECS is a second control loop which measures the controller response and alters the command signal to achieve the desired response. Controller performance is presented and compared with the significant improvement achieved using DECS.
© (1994) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
John B. Thatcher, John B. Thatcher, Robert R. Clappier, Robert R. Clappier, Ray Von Savoye, Ray Von Savoye, "Primary mirror controller with digital error correction", Proc. SPIE 2227, Cryogenic Optical Systems and Instruments VI, (23 June 1994); doi: 10.1117/12.178612; https://doi.org/10.1117/12.178612

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