Systematic design methods of robust and structured controllers for satellites. Application to the refinement of Rosetta's orbit controller

Abstract

In this paper, the capability of nonsmooth optimisation techniques to solve complex control problems with implementation issues is addressed. {H}_{∞}/ μ design methods are analysed to enhance the current Airbus Defence and Space industrial development process. In the first instance, a reference μ-synthesis controller that achieves the desired robust performance level is designed. Second, a controller obeying the same initial design objectives is synthesized using a predefined fixed structure and order. This time, the controller is realised using a fixed-structure-based μ-synthesis approach involving a nonsmooth optimisation algorithm provided in the Matlab R2011b Robust Control Toolbox. Finally, a practical structured {H}_{∞} multi-model approach closer to Airbus Defence and Space development practices is proposed. The different methodologies are applied to synthesize the Chemical Station Keeping controllers of a flexible Eurostar E3000 satellite and a comparative performance robustness analysis is provided. Hinfstruct has now been established in the Airbus Defence and Space industrial process. Recently, it has been successfully used to rapidly refine the orbit controller of Rosetta Space Probe before the critical rendezvous with Comet 67P/Churyumov-Gerasimenko. A specific section will be devoted on this point and in-flight data will be presented.