On the Worst Disturbance of Airplane Longitudinal Motion using the Generic Transport Model

Abstract

In gust alleviation control synthesis, it is important how to generate the worst disturbance that has the worst effects on aviation. This paper applies the worst disturbance method based on H^∞control to a linearized airplane motion model and provides new insights into the relationship between the initial condition and the worst disturbance. In addition, this paper utilizes Generic Transport Model (GTM) which is a nonlinear airplane motion model developed by NASA and discusses whether the linear model results are applicable for GTM. The first result is that the proposed worst disturbance algorithm allows us to analyze the relation between the initial conditions and short-period/Phugoid modes of longitudinal motion and especially tends to decrease the damping ration of the short period mode. The second result is to show that H^∞control is applicable for GTM within the small perturbation around the trim condition and there are the same oscillation behaviors between the linear and nonlinear models.