Onboard trajectory generation for gyroplane unpowered landing based on optimal lift-to-drag ratio target

Abstract

To achieve the autonomous unpowered landing for gyroplanes, an onboard trajectory generation method is presented in this paper. As a pivotal variable in the proposed method, the Lift-to-Drag Ratio will be uniquely determined in different phases by finding the maximum for the energy margin during approaching and the energy decrease at terminal landing. Especially, autorotation constraint, the primary requirement of gyroplanes for flight stability, has been considered as a limitation factor through this procedure. Furthermore, a geometrically constrained three-dimensional trajectory profile is employed, in which a multi-circle Heading Align Cone is proposed to improve its applicability. Accordingly, a predictor–corrector algorithm is derived and described for trajectory generation with initial variance and terminal requirements. Employing the algorithm onboard, by adjusting few geometric parameters dynamically, a feasible trajectory reference that meets the specified constraints can be generated efficiently. Results from numerical calculation and closed-loop simulation under different scenarios demonstrate the effectiveness and robustness of the approach.