The performance of a telescope position control servosystem depends on its ability to minimize changes in position due to wind and other disturbances. Modern, lightweight telescopes such as WIYN rely on feedback to achieve good disturbance rejection. While the simplicity of a direct, friction-drive system is attractive, the small drive ratio greatly diminishes the effectiveness of motor velocity control in reducing disturbance sensitivity. The WIYN servosystems use position feedback and motor torque control to achieve tracking accuracy and disturbance rejection. This type of control allows the use of larger position control bandwidth than is possible with motor velocity control. The factors affecting disturbance rejection are discussed. Motor velocity controlled and motor torque controlled servosystems are described and compared. The WIYN telescope is analyzed to show the expected performance of each type of system, and measured performance is presented.

Date Published: 8 June 1995
PDF: 11 pages
Proc. SPIE 2479, Telescope Control Systems, (8 June 1995); doi: 10.1117/12.211453

Published in SPIE Proceedings Vol. 2479:
Telescope Control Systems
Patrick T. Wallace, Editor(s)