Abstract: The present invention provides a method for disturbance compensation based on a sliding mode disturbance observer for a spacecraft with a large flexible appendage, comprising steps of: a) building a spacecraft attitude control system; b) constructing an external system, the external system being incorporated with an uncertain portion of a damping matrix of a flexible appendage of the spacecraft; the external system being incorporated with an uncertain portion of a rigidity matrix of the flexible appendage of the spacecraft and describing a sum of flexible vibration and environmental disturbance; c) configuring a sliding mode disturbance observer for estimating the value of the sum of flexible vibration and environmental disturbance; d) compounding a nominal controller with the sliding mode disturbance observer in step c) to obtain a compound controller; the compound controller compensating for the sum of flexible vibration and environmental disturbance.

Abstract: The present invention provides a method for attitude control based on finite time friction estimation for a flexible spacecraft. The control method includes the following steps: a. introducing spacecraft flywheel friction disturbance into a spacecraft dynamics system, and establishing a flexible spacecraft dynamics system with flywheel friction disturbance; b. converting the flexible spacecraft dynamics system with flywheel friction disturbance into a state-space form; c. constructing a flywheel friction disturbance estimator; d. constructing a flexible appendage vibration disturbance observer; and e.