Fig. 1. Coordinate reference frame system of spacecraft

Fig. 2. Block diagram showing the flow of the control signals for the PTSMC scheme.

Fig. 3. Attitude tracking errors of PTSMC and SOPTSMC

Fig. 4. Angular velocity tracking errors of PTSMC and SOPTSMC

Fig. 5. Control inputs of PTSMC and SOPTSMC

Fig. 6. Attitude tracking errors of PTSMC， PD and NTSMC

Fig. 7. Angular velocity errors of PTSMC， PD and NTSMC

Fig. 8. 3-DOF free-flying robot floating platform

Fig. 9. Attitude tracking experimental results of the floating platform of a 3-DOF free-flying robot

Fig. 10. Changes of x， y and ϕ of the floating platform with time