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Mathematical Problems in Engineering
Volume 2016, Article ID 2138190, 9 pages
http://dx.doi.org/10.1155/2016/2138190
Research Article

Speed Control Based on ESO for the Pitching Axis of Satellite Cameras

1Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei 230027, China
2Key Lab of Electric and Control of Anhui Province, Anhui Polytechnic University, Wuhu 241000, China
3Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033, China

Received 20 November 2015; Revised 19 February 2016; Accepted 13 March 2016

Academic Editor: Mingcong Deng

Copyright © 2016 BingYou Liu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The pitching axis is the main axis of a satellite camera and is used to control the pitch posture of satellite cameras. A control strategy based on extended state observer (ESO) is designed to obtain a fast response speed and highly accurate pitching axis control system and eliminate disturbances during the adjustment of pitch posture. First, a sufficient condition of stabilization for ESO is obtained by analyzing the steady-state error of the system under step input. Parameter tuning and disturbance compensation are performed by ESO. Second, the ESO of speed loop is designed by the speed equation of the pitching axis of satellite cameras. The ESO parameters are obtained by pole assignment. By ESO, the original state variable observes the motor angular speed and the extended state variable observes the load torque. Therefore, the external load disturbances of the control system are estimated in real time. Finally, simulation experiments are performed for the system on the cases of nonload starting, adding external disturbances on the system suddenly, and the load of system changing suddenly. Simulation results show that the control strategy based on ESO has better stability, adaptability, and robustness than the PI control strategy.