Automatic Aircraft Loss-of-Control Prevention by Bandwidth Adaptation

An automatic aircraft loss-of-control prevention system by bandwidth adaptation is presented in this paper. The adaptation law employs the time-varying parallel differential eigenvalues for a tradeoff between tracking performance and severe wind tolerance capability in real time. It is implemented as an augmentation to a 6-DOF trajectory tracking controller designed with constant gains by the singular perturbation (timescale separation) principle in a multiple-timescale nested-loop architecture. Theoretical analysis is presented to justify the design rationale. It relates the ratio of timescale separation between the inner and outer loop (singular perturbation) to the phase margin of the outer-loop (perturbed) system, which is important in its own right. Simulation studies on tailwind, headwind, crosswind, downdraft, and updraft are presented to demonstrate the effectiveness of the proposed loss-of-control prevention strategy.