Attitude control using higher order sliding mode

This paper proposes a chattering-free global finite-time convergent robust control method for the attitude control of a rigid spacecraft. The control method is formulated using higher order sliding mode control in integral sliding mode. The sliding mode order is higher than the system relative degree and therefore, chattering elimination is ensured. In the control design process, unmeasured sliding vector derivative is estimated using a robust exact differentiator. To verify the effectiveness of the proposed control method, simulations are performed in the presence of external disturbances and inertia uncertainty. The proposed controller successfully negates the effect of external disturbances and inertia uncertainty and attitude states attain the desired accuracy with good steady state precision and high convergence speed.