Finite-time control for electromagnetic satellite formations

The current paper investigates the electromagnetic formation flight control problem using the finite-time control technique. The electromagnetic force model is presented, and the effects of the Earth's magnetic field on the EMFF satellites are analyzed. The equations of relative motion and general formation description method are then established. A robust sliding mode controller is designed to achieve trajectory tracking in the presence of model uncertainties and external disturbances. The proposed controller, which combines the advantages of linear and terminal sliding mode controls, can guarantee the convergence of tracking errors in finite time rather than in the asymptotic sense. By constructing a particular Lyapunov function, the closed-loop system is proven globally stable and convergent. Numerical simulations of formation maintenance and reconfiguration are then presented to show the effectiveness of the developed controller.

► Far-field model is valid when distance is larger than 6.76 times of coil radius.
► The proposed robust control approach can guarantee finite-time convergence.
► The linear and terminal sliding mode control schemes are considered.
► The proposed approach can guarantee global fast convergence with higher accuracy.