| The objective of this research was to design flight control laws for supermaneuverable aircraft. Such aircraft routinely operate with high angle-of-attack and high angular rates where nonlinearities are significant. The research showed that a nonlinear dynamic-inversion control law could be readily designed and implemented. The control law exploited the two-time scale nature of the controlled dynamics. This allowed the design to consist of two first-order inversions in sequence. One inversion used three high-bandwidth inner loops to control the fast states corresponding to the three body-axis, angular rates. The second inversion was approximate and employed outer loops to control the angle-of-attack, sideslip angle and the rate of the bank angle about the velocity vector. Simulations of aggressive maneuvers showed that the control law provides accurate control of these variables, even in the presence of static perturbations to the mathematical model.; For comparison, a more conventional, gain-scheduled linear controller was designed. The gain-scheduled controller produced less accurate control of the angle-of-attack and higher levels of sideslip and lateral acceleration than the dynamic-inversion system.; Dynamic inversion offers a natural method of incorporating thrust vectoring control into the control law. This produced smaller control deflections during simulations than the gain-scheduled system. An enhancement to the dynamic-inversion control law was developed to allow the aircraft to reach very high roll rates, causing the ailerons to saturate, while retaining accurate control of sideslip.; A secondary objective in the research was to design a maneuver generator, to provide the pilot commands during the simulations. The basic maneuver generator, which uses dynamic inversion of the point-mass equations, provides adequate performance. The thesis examines various configurations of maneuver generator and suggests possible enhancements. |
