Design of Robust Autopilot Control Laws with Nonlinear Dynamic Inversion

Abstract

The application on Nonlinear Dynamic Inversion for the design of a robust attitude controller for a civil aircraft is discussed. The main function of the controller is to improve the flying qualities, including stability, of the aircraft dynamics. For parameter synthesis multi-objective optimisation is used. The required robustness is achieved via a multi-model approach and local robustness criteria. In addition to the feedback gains, physical parameters in the inverse model that are considered uncertain in the design model, are used as synthesis parameters. The control laws are automatically genereted from a symbolic aircraft model in the modeling language Modelica. The design was used as a stability and command augmentation function in an automatic Fly-by-Wire landing system and was successfully flight tested.