The control system for the Multipurpose Multiple Telescope Testbed (MMTT) is described. Performance of the control system is measured against the goal of maintaining lateral pupil geometry to within one micron of the ideal. The MMTT control system consists of four channels. A discrete-time-varying Kalman filter processes the sensor measurements to estimate lateral pupil geometry and piston errors in each channel. The controller integrates the Kalman filter estimates along with the x- and y-tilt measurements, which are treated deterministically. Multiplication by an axis separator matrix converts the control input commands into appropriate piezoelectric transducer actuator commands. The commands from each control channel remove piston, tilt, and pupil geometry error between each telescope and the telescope denoted the reference. The entire control algorithm is implemented on high-speed array processor boards. Preliminary test results show that the control system is accurately controlling lateral pupil geometry for small field angles. For larger field angles, the system is unstable due to parameter variations.

Date Published: 1 July 1990
PDF: 11 pages
Proc. SPIE 1236, Advanced Technology Optical Telescopes IV, (1 July 1990); doi: 10.1117/12.19215

Published in SPIE Proceedings Vol. 1236:
Advanced Technology Optical Telescopes IV
Lawrence D. Barr, Editor(s)