Flight Control Design using Nonlinear Inverse Dynamics

Aircraft in extreme flight conditions such as stalls and spins experience nonlinear forces and moments generated from high angles of attack and high angular rates. Flight control systems based upon nonlinear inverse dynamics offer the potential for providing improved levels of safety and performance in these flight conditions over the competing designs developed using linearizing assumptions. Inverse dynamics are generated for specific command variable sets of a 12-state nonlinear aircraft model to develop a control system that provides satisfactory response over the entire flight envelope. Detailed descriptions of the inertial dynamic and aerodynamic models are given, and it is shown how the command variable sets are altered as functions of the system state to add stall prevention features to the system. Simulation results are presented for various mission objectives over a range of flight conditions to confirm the effectiveness of the design.