Nonlinear observer based time delay fault-tolerant attitude control for flexible spacecraft during orbit maneuver

A nonlinear attitude control approach and fault-tolerant control approach are put forward in this paper. Firstly, based on the nonlinear observer, a higher order sliding mode attitude control approach is designed for the flexible spacecraft attitude control system when the actuators are working normally. The nonlinear observer has a good estimation of orbit control force, internal disturbances and environment disturbances thus ensure the robust of attitude controller and the higher order sliding mode control method can well suppress the vibration of the sliding method itself and eliminates the observe deviation. On this basis, a fault-tolerant attitude controller is designed in presence of actuator multiplicative fault and bias fault based on time delay technology. At last, simulation is done on the flexible spacecraft´s attitude system during its orbit maneuver process and simulation results demonstrate the effectiveness and correctness of the proposed attitude control approaches.