Computational intelligent satellite attitude control design
- Paper number
IAC-08.C2.3.5
- Author
Dr. Ernesto Araujo, Instituto Nacional de Pesquisas Espaciais (INPE), Brazil
- Coauthor
Mr. Luiz Carlos Gadelha De Souza, Instituto Nacional de Pesquisas Espaciais (INPE), Brazil
- Coauthor
Mr. Fausto Ramos, CTA/ Institute of Aeronautics and Space, Brazil
- Year
2008
- Abstract
A Computational Intelligence (CI) mechanism for control system design employing robust and random-search techniques applied to a satellite attitude control system by using a reaction wheel is presented in this paper. The design time and the robustness issue when dealing with the uncertainty of the satellite model parameters were also taken into account demonstrating that on-line design is possible even with large discrepancies of the nominal values. This on-line approach is important in the cases where the system performance is spoiled when parameters of the system changes in time. The embedding of computational intelligence mechanisms in control system design may be attractive for reconfiguration purposes. Moreover, it has demonstrated that effective search and scoring procedures can replace human-performed trial-and-improvement actions for gain computation, and produce performance indexes and torque levels compatible with real world specifications. The Computational Intelligence mechanisms employed in this paper intertwine genetic algorithm, which generates, combines, and selects optimized gains for controllers candidates, and fuzzy system, for scoring performance indexes and torque levels of the controller candidates which, in turn, are subsequently used by the genetic algorithm. A variation of this control approach, recently proposed by the authors in a previous paper, demonstrated its usefulness when using linear quadratic (LQ) techniques while the approach described in this paper innovates when employing H-2 techniques. Not only the controller gains themselves are used as candidates, but weighting signals for the H-2 technique are used, as well. Results are obtained when applying the proposed approach in a FireSat example. Simulations in this paper is, then, extended to a nonlinear satellite model differing from previous paper when a linear satellite model was employed. In order to demonstrate the effectiveness of the method, it is provided a comparison of three controllers based on the proportional-derivative (PD), an H-2 and a DISO first-order techniques. This paper explores yet the consequences when the H-2 controller is truncated in order to obtain lower-order controllers to suppress the disadvantage of robust techniques that usually supply high-order controllers. In doing so, this truncated H-2 controller is compared with DISO controllers of same order showing its vantages when compared with more traditional techniques nowadays employed in this context.
- Abstract document
- Manuscript document
IAC-08.C2.3.5.pdf (🔒 authorized access only).
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