Rigid spacecraft preset time fault-tolerant attitude control strategy

The invention discloses a rigid spacecraft preset time fault-tolerant attitude control strategy, which is characterized in that a control target is achieved through the construction of a preset time fault-tolerant controller and a preset time attitude controller, wherein system upper bounds with incomplete fault of an actuator, saturation of an actuator, external interference and uncertainty of system inertial parameters are estimated in real time within a preset time through an obstacle self-adaptive law based on an integral sliding mode while uncertain items of the system within the preset time are compensated so as to realize fault-tolerant control within the preset time, and then a preset time attitude controller based on a second-order sliding mode variable is designed to realize that an attitude tracking error converges to zero within preset time. According to the control strategy, the attitude tracking control problem of the rigid spacecraft under the conditions of incomplete actuator fault, actuator s