Hybrid Control of Fixed-Wing UAVs for Large-Angle Attitude Maneuvers on the Two-Sphere

Abstract

We propose the design of a hybrid controller for fixed-wing unmanned aerial vehicles which guarantees global exponential tracking of attitude references on the two-sphere. The chosen attitude representation is singularity-free and can be exploited to apply proportional feedback along the shortest path in the natural configuration space, giving it an advantage to conventional design methods based on Euler angle reprentations. The design includes the concept of synergistic potential functions to overcome the problem of a vanishing potential at the additional undesired equilibrium on the compact manifold. It employs proportional-derivative feedback with the relative velocity as an exogeneous input and allows for integration into conventional autopilot architectures. The controller is well-suited for the recovery from large attitude disturbances and the performance is demonstrated in a numerical example.