Fractional Order Adaptive Sliding Mode Control for the Deployment of Space Tethered System With Input Limitation

Abstract

This paper develops a novel sliding mode control strategy for the deployment of space tethered system with consideration of constrained input. The simplified nonlinear dynamic model of space tethered system in elliptical orbits is first modeled by using the Euler–Lagrange mechanical equation. Considering the flexibility of tether, the compression or any component of shear forces for the tether is assumed to be input limitation. By introducing fractional order operator and saturation function into the sliding surface, a new adaptive fractional order sliding mode control strategy is introduced based on the proposed nonlinear dynamic model. Compared with classical sliding mode methods, a faster deployment time without overshoot and chattering-reduced performance can be achieved. Finally, numerical simulations are illustrated to validate the effectiveness of our methods.