Adaptive Prescribed-Time Output-Constrained Control of Mars Powered Descent Phase With Unmeasured Input Deadzone and Unknown Mass

The presence of unmeasured parameters and unknown disturbances presents substantial challenges in the controller design of the Mars landing mission. In this article, the problem of adaptive prescribed-time tracking control for the powered descent phase of Mars landing with time-varying output constraints, unmeasured input deadzone nonlinearity, unknown vehicle mass, and disturbances is addressed. First, a prescribed-time output-constrained function is defined, and a class of time-varying barrier Lyapunov functions (BLFs) is developed, including estimation error information for disturbances and system parameters. Then, based on these functions and Nussbaum-type functions, an adaptive prescribed-time tracking control scheme is proposed for the powered descent phase of Mars landing in the presence of time-varying output constraints, unmeasured input deadzone nonlinearity, and unknown vehicle mass such that the tracking error converges to zero in a prescribed time and the control signals are bounded. Finally, several numerical simulations validate the effectiveness of the proposed method.