Model Predictive Control With Wind Preview for Aircraft Forced Landing

Autonomous emergency landing capability of fixed-wing aircraft is essential for opening airspace for civil unmanned aviation. This article proposes a goal-oriented control scheme to exploit wind information for the benefit of forced landing. Different from general disturbances in a classic control system, a favorable wind would help aircraft to glide to a selected landing site more easily so increase the level of safety while an adverse wind may render a selected landing site infeasible. We formulate the forced landing problem with wind preview information in the framework of economic model predictive control (EMPC), which aims to maximize the aircraft's final altitude when reaching a target region. A double-layer model predictive control (MPC) scheme is adopted to lessen the computational burden and to increase the prediction time window for practical implementation, where a piecewise-constant disturbance-preview-based EMPC maximizes the altitude at the upper level, and a linear MPC is employed at the lower level to track the reference signal optimized by the upper-level planner. Moreover, the effectiveness of the goal-oriented optimal control scheme is illustrated by several case studies, where an unmanned aircraft is gliding toward potential landing sites under various conditions.