Nonlinear dynamics and reconfiguration control of two-satellite Coulomb tether formation at libration points

The use of inter-satellite electrostatic (Coulomb) forces for formation flying is attractive due to the prominent advantages of no propellant consumption or plume impingement issues. This paper investigates the nonlinear attitude–orbit coupling dynamics and control for the reconfiguration of a two-satellite Coulomb tether formation near Earth–Moon libration points. The nonlinear dynamic model is derived by utilizing analytical mechanics theory, and analysis on environment disturbance related to the solar radiation pressure effects is put forward. Considering the high nonlinearity and uncertainty in the dynamic model, a closed-loop control strategy based on the indirect robust control scheme and the θ–D method is proposed with precise and good robust performance. Here, the Coulomb force is used for the longitudinal direction control, and the inertial micro-thrusters are activated for control in the transverse directions. Theoretical analysis and numerical simulation results are presented to validate the feasibility of the proposed dynamics model and proposed control strategy for the robust reconfiguration and station-keeping mission.