Abstract: The controller design of Drag-Free satellites on near-earth orbit is the object of the study. After analyzing characteristics of main disturbances affecting Drag-Free satellites, a disturbance dynamics model is established. Adding the disturbance to the system, a disturbance observation based-dynamics model of Drag-Free satellite is built. Then a mixed H2/H∞ controller is designed and the LMI form is used to solve it. Simulation results verify stability and feasibility of the controller.

Key words: DraG-Free satellite, Disturbance observation, LMI