Nonlinear flight control problem on decentralized sliding modes

This paper proposes applying sliding mode stabilization to aircraft flight control. The nonlinear multiple inputs, multiple outputs problem of controlling aerodynamic angles, trajectory angles, attitude angles and energy, is addressed by methods of variable structure control. The paper shows the need to optimize for each phase of the mission the selection of the output variables used by the pilot to control the flight. The paper shows that due to specifics of aircrafts and of flight mechanics this set of variables is in general not optimum or simply not adequate for a robust tracking. It analyses the rationale for selecting the set of variables to be tracked. Since the two sets do not coincide, the paper proposes the method for deriving the profiles to track described in terms of tracking variables from their specification in mission variables. It studies the application of sliding modes techniques to track the prescribed profiles. It demonstrates that by tracking the profile in one of the reference systems the profile is also tracked in the other reference system