| Summary: | 博士 === 國立成功大學 === 電機工程學系碩博士班 === 90 === In this dissertation, nonlinear control , mixed and LMI control design methods are proposed to solve large-angle robust attitude control and tracking of spacecraft. The robust attitude control problem is formulated as thruster control and wheels control where the desired stability and disturbance rejection are achieved. For the ROCSAT-3 spacecraft, a highly accurate and robust attitude control is desired during the orbit-raising phase and the other mission modes. The three-axis attitude control is achieved using 1) four body-fixed, canted thrusters or 2) a cluster 4 wheels. The nonlinear dynamic equations of the satellite are derived and the control requirements are stated. The dissertation investigates both attitude stabilization and tracking problems. As to the former, the nonlinear controller parameters are designed using nonlinear control , mixed and linear matrix inequality (LMI) method in thruster and wheels control models. As to the latter, the nonlinear controller that asymptotically tracks a desired reference trajectory under parameter variations and external disturbance is investigated. Asymptotic tracking is ensured under suitable restraints of the reference inputs. Simulation results based on the ROCSAT-3 system are then presented to demonstrate the proposed design method.
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