Flight control design using hierarchical dynamic inversion and quasi-steady states

Abstract

Design of kernel control laws is an important step in autonomous flight control design for UAVs, because the function of kernel control laws is to guarantee asymptotical inner-loop stability of aircraft motion relative to the surrounding air. The design can be further complicated by nonlinear flight dynamics. In this paper, we propose a hierarchical dynamic inversion (HDI) method for design of the kernel control law for a fixed-wing UAV based on quasi-steady states. HDI is more generally applicable to some non-affine nonlinear systems. The designed kernel control law is incorporated into an autonomous flight controller and verified in simulation based on the high-fidelity 6-DOF nonlinear model of a UAV. The simulation results demonstrate that the UAV with the designed kernel control law successfully execute super maneuver and is robust against actuator gain variation. © 2008 by the American Institute of Aeronautics and Astronautics, Inc.