Constrained nonlinear tracking control for small fixed-wing unmanned air vehicles

This paper considers the problem of constrained nonlinear tracking control for small fixed-wing unmanned air vehicles equipped with longitudinal and lateral autopilots. Four different controllers based on SDRE, Sontag's formula, geometric mean, and aggressive selection from the feasible control set are proposed and compared to show their strengths and weaknesses under different application scenarios. Issues of measurement noise and input uncertainties are also addressed under the input-to-state stability framework. The effectiveness of the approaches is demonstrated through detailed simulation studies.