Twisting algorithm for controlling F-16 aircraft with performance margins identification

A Twisting algorithm based second order sliding mode controller is designed for tracking of command angles for nonlinear flight dynamics of an F-16 aircraft, before and after the battle damages. The high frequency switching controller is designed in terms of control derivative so that the actual control function is continuous. The practical robustness performance margins are identified in terms of maximal additional gain (Practical Gain Margin) and phase lag (Practical Phase Margin) added to the frequency characteristic of the linear part of the open loop system that yield acceptable loss of command angle tracking performance in terms of admissible parameters of self sustained oscillations. The effects of parasitic dynamics, in terms of linear first order actuator dynamics, on the controller's performance are analyzed. The performance margins in terms of parameters of parasitic dynamics are obtained. The proposed approach is verified via simulations.