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Proceedings Paper

Observer-based higher order sliding mode control for large optical astronomical telescopes
Author(s): Wangping Zhou; Xiaoling Ye; Wei Guo; Zhonghua Wu
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Paper Abstract

In order to study more remote universe and the detailed structures of near stars, large-scale astronomical telescopes are very needed with the development of astronomy and astrophysics. In this trend, astronomical telescope becomes more and more huge, which leads its driving system to bear heavy nonlinear disturbances. The increased nonlinear disturbances especially caused by friction torque in the control system can easily bring tingle and stick-slip phenomena when the telescope tracks an object with an ultra-low velocity. However, conventional control approaches are difficult to realize high-precision controls and can decrease the quality of a telescope's observations. Therefore, it will be of significance in theory and in practice to develop an advanced new control method to restrain nonlinear disturbance and improve telescope's observation performance. Sliding mode approach has been applied in many other mechanical control systems since it is invariable to various disturbances. However, conventional sliding mode approach may cause dangerous high-frequency vibrations in corresponding control system, which may influence control performance or even lead the system unstable. To counteract the effect of above nuisance, a high-order sliding mode (HOSM) controller of third-order has been suggested in the large telescope's drive system through theoretic deduction and analysis. On account of that the HOSM approach needs all system states available, a sliding mode observer has then been designed in order to get the acceleration state of the drive system. Simulation results show that this approach can obtain high control precision and may satisfy the requirements of a telescope for a nicely ultra-low velocity.

Paper Details

Date Published: 5 May 2009
PDF: 5 pages
Proc. SPIE 7281, 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, 72810E (5 May 2009); doi: 10.1117/12.831438
Show Author Affiliations
Wangping Zhou, Nanjing Univ. of Information Science & Technology (China)
Xiaoling Ye, Nanjing Univ. of Information Science & Technology (China)
Wei Guo, Nanjing Univ. of Information Science & Technology (China)
Zhonghua Wu, Graduate School of the Chinese Academy of Sciences (China)

Published in SPIE Proceedings Vol. 7281:
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes
Wenhan Jiang; Roland Geyl; Myung K. Cho; Fan Wu, Editor(s)

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