Predefined-Time Control of a Spacecraft Attitude with Thrust Booms

A predefined-time attitude controller for electric spacecraft and its thrust booms is investigated by combining a second-order sliding mode control with predefined-time disturbance observer. First, an Eulerian-Lagrangian attitude dynamics model of the electric spacecraft with thrust booms is constructed; meanwhile, the coupling between the spacecraft platform and thrust boom is treated as the disturbance when designing the controller. Next, a predefined-time convergent second-order sliding surface and reaching law are designed to ensure the predefined-time fast convergence. The second-order sliding surface can avoid the chattering problem of controller and improve the anti-disturbance capability of the spacecraft. Furthermore, a novel predefined-time disturbance observer is developed to handle the disturbances, ensuring that the tracking error of the system converges to the equilibrium. At last, the simulation is performed to verify the feasibility and advantages of the proposed algorithm.