Finite-time Autonomous Shipboard Landing Control of a Helicopter with Time-varying Output Constraints

This paper addresses a finite-time autonomous shipboard landing problem of a model helicopter subject to output constraints, parametric uncertainties and external disturbances. By establishing the relative motion model between the helicopter and the ship, the shipboard landing problem is converted from a general trajectory tracking problem to a stabilization problem. Due to the under-actuated property of the helicopter, the whole process of the autonomous shipboard is divided into two steps. The helicopter is first commanded by a relative position controller (RPC) to reach above the ship. As it reaches, a relative attitude-altitude controller (RAC) is initiated to guide the helicopter to descend steadily on the ship. RPC and RAC are both devised in terms of the tan-type Barrier Lyapunov Function theory, with an adaptive estimation method inserted to compensate for the impact of uncertainties and disturbances. It is demonstrated from the stability analysis that the proposed control strategy can ensure that system tracking errors converge to small sets around zero in the finite time and never violating constraint requirements. Numerical simulations are implemented to further validate the remarkable control performance.