Robust control of a nonlinear non-minimum phase supersonic flight vehicle based on stable system center

Design and synthesis of a nonlinear time-varying and non-minimum phase supersonic flight vehicle longitudinal dynamics control for g-commands output tracking are presented. Differential geometric approach utilized to outline system relative degree and unstable internal dynamics explored based on the vehicle dynamics transformation into a nonlinear normal form. Unstable internal dynamics are then invoked to identify ideal state reference profiles leading to a desired output-tracking problem. Compensated internal dynamics converged to a solution on the system center manifold for ideal internal dynamics asymptotically. Finally, sliding mode control employed based on an appropriate sliding manifold to track the reference input while being robust against uncertainties. Simulation results are performed and effectiveness of the designed approach demonstrated.