| Aircraft control is a Multiple Input, Multiple Output, non linear time varying control problem. It is characterized by a considerable degree of coupling of the modes. Sliding mode control appears to be an elegant and simple solution to the aircraft control problem. It addresses the non linear and largely uncertain nature of the plant and achieves a particularly robust control. Similarly to what is recommended by multiple authors, the control architecture is layered into an outer loop, slow states loop and an internal, fast states loop. The choice of the outer loop, slow variables or mission variables, used to specify the prescribed maneuver, is dictated by operational considerations. In order to design the aircraft control using sliding modes, the pitch, roll, yaw and energy channels are analyzed separately. The Thesis identifies the set of tracking variables that can be tracked in the inner loop, in Sliding Modes. It shows that due to unstable internal dynamics only few of the inner loop candidate variables can be tracked in sliding mode. The transformation that converts the prescribed mission profiles to the tracking variables is developed.; Sliding Mode Control provides a robustness not achieved by other designs, while achieving a precision of the tracking, competitive with state of the art performances. |
