Robust attitude maneuver control of spacecraft with reaction wheel low-speed friction compensation

This paper investigates the attitude control problem in the presence of wheel low-speed friction and external disturbances. The critical issues surrounding wheel friction are firstly discussed, and the spacecraft attitude model and wheel friction model are introduced. A friction observer that can effectively estimate the friction torque is developed. An observer-based sliding mode controller, to perform attitude maneuver, is then proposed. By constructing a particular Lyapunov function, the stability and performance of the proposed controller for the closed-loop systems is discussed theoretically. Numerical simulations are finally provided, and the results have demonstrated that the friction is compensated by the observer and the proposed controller has better transient and steady-state performance.