Washout Filters in the Bifurcation Control of High Alpha Flight Dynamics

Washout filters are employed in the design of stabilizing controllers for systems undergoing bifurcations. Moreover, the advantages of using washout filters are demonstrated in the control of a high angle-of-attack nonlinear aircraft model. In the bifurcation control of an F-8 model in [2], the performance of the controller depended on a priori computation of equilibrium curves. Moreover, the controller tended to result in reshaping non-nominal equilibrium branches. Since this could result in a nearby equilibrium point moving toward the trim condition, it is undesirable. In this paper, by complementing the technique of [2] with washout filters for the control of F-8 high alpha dynamics, a fixed controller can be used through a range of flight conditions, without affecting the set of open-loop equilibria. The stability of the equilibrium of interest is, however, significantly enhanced.