Barrier Lyapunov function based sliding mode control for Mars atmospheric entry trajectory tracking with input saturation constraint

The nature of the bank angle modulation technique based on the low lift-to-drag aerodynamic configuration of the entry vehicle inevitably introduces the problem of input saturation, which would lead to unexpected tracking performance degradation. To this end, a barrier Lyapunov function (BLF) based sliding mode control is proposed for the Mars atmospheric entry trajectory tracking in this paper. A variable gain super-twisting (VGST) based terminal sliding mode controller is firstly presented. By introducing a novel logarithm-type BLF, the proposed terminal sliding mode controller is proved stable with bounded convergence time in the presence of input saturation and external disturbance. Then, based on the numerical predictor–corrector strategy, the variable gain of terminal sliding mode controller is adjusted onboard to satisfy the constraint of input saturation. The Mars Science Laboratory Mission based atmospheric entry scenario is utilized in the numerical simulation to verify the proposed trajectory tracking method, demonstrating the effectiveness of method of BLF based terminal sliding mode controller design.