Spacecraft attitude control via new non-singular fast terminal sliding mode control

In the final approach phase of rendezvous in space, the chaser attitude control system is expected to track the given attitude with high precision under the influences of disturbances. Furthermore, the attitude tracking mission is required to be completed in finite time. To satisfy those requirements, an attitude controller is presented by combining non-singular fast terminal sliding mode control (NFTSMC) with higher order sliding mode (HOSM) concept. The proposed controller contains two parts: one is used to achieve finite time stabilization of the higher order input-output dynamics without uncertainties; the other is made to reject the bounded uncertainties. By the virtue of HOSM, the chattering phenomenon can also be attuned. Numerical simulations are performed to verify the effectiveness of the proposed strategy.