Adaptive model inversion flight control for tilt-rotor aircraft

Neural-network augmented model inversion control is used to provide a civil ian tilt-rotor aircraft with consistent response characteristics throughout its operating envelope, including conversion flight. The implemented respo nse type is Attitude Command Attitude Hold in the longitudinal channel. Con ventional methods require extensive gain scheduling with tilt-rotor nacelle angle and speed. A control architecture that can alleviate this requiremen t, and thus has the potential to reduce development time and cost, is devel oped. This architecture also facilitates the implementation of desired hand ling qualities and permits compensation for partial failures. One of the po werful aspects of the controller architecture is the accommodation of uncer tainty in control as well as in the states. It includes an online, i.e., le arning-while-controlling, neural network that is initialized with all weigh ts equal to zero. Lyapunov analysis guarantees the boundedness of tracking errors and network parameters. Performance of the controller is demonstrate d using a nonlinear generic tilt-rotor simulation code.