NONLINEAR ATTITUDE CONTROL OF RIGID SPACECRAFT WITH FLEXIBLE STRUCTURE

• Main Authors: Gern-Liang Lin, 林耕良
• Other Authors: Yiing-Yuh Lin
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/64511678074665389524

博士 === 國立成功大學 === 航空太空工程學系 === 88 === Two methods of adaptive damping and variable structure control incorporating the stable vibration control are applied in this dissertation for the simultaneous multi-axis reorientation of a rigid spacecraft with flexible structures. Uniqueness of the methods are that only three attitude torque actuators in the hub are required for the designed control law. Modeling of the dynamic system gives a set of coupled ordinary and partial differential equations, which includes the attitude dynamics of the spacecraft and the dynamics of the flexible structures. To design the control law, the deformations of the flexible structure were assumed small and the mode-shape functions were applied first to simplify the system equations. The set of nonlinear equations governing the attitude motions were transformed into Euler parameters or modified Rodrigues parameters (MRP) representation. Through the methods of adaptive damping or sliding mode control and vector subtraction in parameter space, the changes of the attitude errors in the maneuver were formulated as a set of stable second-order ordinary differential equations with constant coefficients, from which the attitude feedback control law was derived. Through Lyapunov stability analysis, the attitude control law with structure stabilization is derived, which ensures the control system to be stable and robust. Vibration control of the flexible structures in the form of adaptive damping or sliding mode were also derived respectively from the procedure of Lyapunov stability analysis and becomes a part of the attitude feedback control law.