Finite-time control for soft landing on an asteroid based on homogeneous system technique

Finite-time control (FTC) for soft landing on an asteroid problem is considered in this paper. Firstly, based on the design philosophy of cascaded system, the landing error dynamics of asteroid probe are divided into two subsystems, including a position error subsystem (PES) and a line-of-sight angle error subsystem (LOSAES). Secondly, homogeneous system technique is employed to design the controller for LOSAES such that the states of LOSAES will be stabilized to the origin in finite time. Then, a finite-time controller is designed for the reduced PES subsystem such that the rest states will converge to zero in finite time. Strict analysis shows that the whole system satisfies the finite time stability. The effectiveness of the proposed method is illustrated by simulation results.