H. Bolandi; F. Fani- Saberi; B. Ghorbani-Vaghei
Volume 1, Issue 2 , December 2008, , Pages 9-15
Abstract
In this paper, the main stereo-imaging methods by high resolution satellites, including Along-Track and Across-Track, have been evaluated and then we will combine the two main stereo-imaging configurations of along track and across track as a new idea to obtain the advantages of both methods. In the ...
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In this paper, the main stereo-imaging methods by high resolution satellites, including Along-Track and Across-Track, have been evaluated and then we will combine the two main stereo-imaging configurations of along track and across track as a new idea to obtain the advantages of both methods. In the proposed stereo-imaging scenario, fast and simultaneous large maneuvers of the satellite around pitch and roll axes is one of the versatile methods. So, highly nonlinear characteristics of the governing equations because of large angle slewing maneuvers are very effective on pointing accuracy and stability and should be considered to design control laws. The purpose of this paper is to design a nonlinear control method using four reaction wheels based on PD controller that can be used to perform a spacecraft large angle maneuver using quaternion attitude variables. The configuration of reaction wheels in the simulated spacecraft has been arranged as a skewed four-wheel reaction. Reaction wheels unloading is also accomplished through the use of three magnetic torquers to prevent the speeds of the reaction wheels exceeding their designed limits, largely as a result of the action of secular components of disturbing torque. Simulation study has verified the performance and effectiveness of the proposed algorithm to achieve the proposed stereo-imaging scenario.
