Modeling and robust nonlinear control of a fixed-wing UAV

A modeling procedure of a fixed-wing UAV as well as a robust controller design methodology are proposed in this paper. Based on the general flight mechanics equations, a numerical model is easily obtained and the steps to determine the aerodynamic coefficients and the actuators dynamics are also explained. Open loop simulations compared with flight data validate the approach. For the design of longitudinal control laws, two strategies are exposed. The first one is based on the classical pole placement method, which serves as a basis for a more recently developed approach. The latter combines partially linearizing inner loops with structured and robust outer loops, which are designed by a non-smooth multi-model H_∞ approach. Successfully tested on simulations, the resulting controller is easily implementable for future experimental flight tests.