Control of a PVTOL Aircraft using Finite-Time Output Feedback

As the roles continue to expand for the unmanned air vehicle (UAV) to include multi-mission tasks, the flight envelope for the UAV is expanding to such a degree that the dynamics of the airframe are becoming increasingly complicated. Already nonlinear, the dynamics are coupled with the uncertainties of the environment, and seized by unpredictable failures including sensor failures, surface failures, or structural damage. Therefore, there is a practical need to develop adaptive and robust controllers, which can adapt to disturbances and sudden dynamic failures. This paper will examine the development of the underlying nonlinear theory required to address the need for greater robustness to environmental and structural constraints in UAV flight control problems. Specifically, the proposed nonlinear controller will have the capability of addressing the issue of uncertainties in a nonlinear model due to the lack of observable states. This paper will implement a finite time output feedback technique coupled with a partially bounded nonlinear control to globally stabilize a planar model of a PVTOL aircraft. The controller will make use of a partially bounded state feedback controller coupled with an observer that will converge in finite-time for a nonlinear aircraft model.