Non-smooth High-precision Control of Drag-free Satellite for Space Gravitational Wave Detection

In this paper, the control mode and working requirements of the drag-free system are introduced. The dynamic model of drag-free satellite with single mass is established along the direction of the sensitive axis in the displacement mode, and the non-conservative forces acting on the satellite platform are analyzed. A continuous time-invariant non-smooth nonlinear state feedback control law is designed for the drag-free system with double integral characteristics, and the stability of the closed-loop system is proved based on Lyaponuv theory. The simulation results show that the non-smooth nonlinear control strategy similar to PD control can ensure the ultra-low bandwidth requirement proposed by the space gravitational wave detection mission while satisfying the high-precision control index requirement for the relative displacement and the residual disturbance acceleration of drag-free satellite platform.