This paper describes the testing and performance evaluation of the Gemini secondary mirror control system. The mechanism and control system have demanding requirements for dynamic performance, precision position control throughout the mirror chop cycle, and the virtual elimination of residual forces and torques. The test procedures and hardware required to measure and verify the system performance were specifically developed for this application. The tests utilize a special computer-controlled laser interferometer to calibrate the mirror position sensors. Dynamic chopping performance of the system is also tested and verified. A range of chop waveform parameters; amplitude, frequency, and duty cycle, is employed to fully exercise the control system and electromechanical hardware. Measurements of angular stability and repeatability under dynamic chop conditions are made to verify performance. Effectiveness of the active force cancellation system is evaluated using a six-axis digital dynamometer.

Date Published: 25 August 1998
PDF: 12 pages
Proc. SPIE 3352, Advanced Technology Optical/IR Telescopes VI, (25 August 1998); doi: 10.1117/12.319279

Published in SPIE Proceedings Vol. 3352:
Advanced Technology Optical/IR Telescopes VI
Larry M. Stepp, Editor(s)