Abstract:

 The libration point rendezvous and docking with a non-cooperative target is investigated based on the high-order integral-chain differentiator and the prescribed performance control theory. Just knowing the relative position states, this paper proposes a new control law for spacecraft rendezvous during the terminal phase. Firstly, the high-order integral chain differentiator is used to estimate the relative velocity states of the two spacecraft, and a mode-free prescribed performance controller is designed, which makes the relative motion states of the two spacecraft asymptotically converge to the desired state within the prescribed boundaries. Then the Lyapunov function is used to prove the stability of the system when there are disturbances in the relative motion states. This method is of closed-loop control and independent of the model parameters, thus it is easy to be employed online. The simulation results show that even though there exist uncertainties such as the unknown disturbances and navigation and guidance errors, the proposed control law can achieve high-precision, real-time control of the spacecraft when tracking the non-cooperative target, and shows strong robustness.
 The libration point rendezvous and docking with a non-cooperative target is investigated based on the high-order integral-chain differentiator and the prescribed performance control theory. Just knowing the relative position states, this paper proposes a new control law for spacecraft rendezvous during the terminal phase. Firstly, the high-order integral chain differentiator is used to estimate the relative velocity states of the two spacecraft, and a mode-free prescribed performance controller is designed, which makes the relative motion states of the two spacecraft asymptotically converge to the desired state within the prescribed boundaries. Then the Lyapunov function is used to prove the stability of the system when there are disturbances in the relative motion states. This method is of closed-loop control and independent of the model parameters, thus it is easy to be employed online. The simulation results show that even though there exist uncertainties such as the unknown disturbances and navigation and guidance errors, the proposed control law can achieve high-precision, real-time control of the spacecraft when tracking the non-cooperative target, and shows strong robustness.

Key words: Circular restricted three body problem, Libration point orbit, High order integral chain differentiator, Low complexity prescribed performance control
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