Robust Controller Design Of Drag-free Satellite With Thrusters’ Uncertainty

Nowadays, with the development of science and technology, space-technologybecomes associated with other industries more and more. Geodesy, Ocean-climatology,Astronomy and the other fundamental subjects put forward higer requirements forspace-technology. The developments of these subjects require satellite providing anenvironment which is low-disturbance, high-precision and stable. Using Drag-Free controlon satellite can provide a platform that can meet the requirements. So, Drag-Free satellitecomes into being.Because the Drag-Free satellite fly in space, so it will be influenced by manyuncertainties, and the thrusters’ uncertainties influence the satellite more. So, the articleconsider the controller design of Drag-Free satellite with thrusters’uncertainties. There aremany control algorithms to design the controller, like Adaptive control, Backstepping,Robust control. The thesis will design the controller of Drag-Free satellite using Robustcontrol. By using the LFT transformation and modeling the uncertainties, the robustcontroller which meet the requirement of hig-precison will be designed, so the Drag-Freesatellite can provide a low-disturbance and high-precision environment.The thesis consider the robust controller design separately when the Drag-Freesatellite has one uncertainty and have two uncertainties. First,the kinetic equations ofDrag-Free satellite is given. Then, model the equations, build the state-space expressionand transform into stardard H design question. At the end, design the Robust controllerusing μ analysis and D-K iteration, and the simulation results illustrate the correctness andeffectiveness of the controller.