Nonlinear Spacecraft Attitude Control Algorithm

With the continuous development of aerospace technology, spacecraft attitudecontrol problem has caught considerable attentions of domestic and foreign expertsand scholars. This thesis studies spacecraft attitude control problems of a singlespacecraft and the formation spacecraft, respectively. This thesis mainly has com-pleted a few aspects as the following:Some defnitions and theories of nonlinear system used in this thesis are intro-duced, and fundamental concept of algebraic graph and relative matrices are intro-duced. Meanwhile, kinematics models described by quaternion and MRP (ModifedRodrigues Parameters) and attitude dynamics models of spacecraft are presented.For single spacecraft, fnite-time attitude control problems are studied. First,under measurable and un-measurable conditions of attitude angular velocities, statusfeedback and output feedback attitude control algorithms are designed respectively.The proposed control schemes guarantee the spacecraft attitude adjusted to thedesired values in fnite time. Secondly, considering the existence of uncertainty ofinertia momentum and disturbance torques, fnite-time attitude tracking controlalgorithm is designed to guarantee the stable of closed loop in fnite time. Then,numerical simulations are for proposed control schemes are performed to verify thefeasibility and efectiveness of them.For formation spacecraft, distributed coordinated attitude control problems arestudied. First, aiming at distributed attitude consensus problem, under directedtopology, attitude coordinated control scheme is proposed to guarantee the atti-tudes' synchronization of formation spacecraft with the existence of communicationdelays. Secondly, considering the existence of uncertainty of inertia momentum anddisturbance torques, sliding mode attitude coordination and tracking control algo-rithm is designed. Furthermore, aiming at the condition that uncertainty of inertiamomentum, disturbance torques and communication delays exist simultaneously; attitude coordination and tracking control algorithm is proposed. For each con-trol algorithm, Lyapunov method is applied to analyze the asymptotical stabilityof the system. Numerical simulations are performed to verify the feasibility andefectiveness of the proposed control algorithms.