Trajectory generation for transition from VTOL to wing-borne flight using inverse dynamics
In this paper, we extend our approach to design a trajectory for executing a specified maneuver by an Uninhabited Aerial Vehicle, or UAV. The trajectory considered spans the flight envelope from VTOL region to wing-borne region. In the process, system configuration with respect to control forces changes. For the wing-borne flight, thrust and aerodynamic control surfaces are used, while for the low velocity flights such as VTOL, thrust vectoring and Reaction Control Systems (RCS) are used for control. We use Inverse Dynamics approach to determine the demand on actuators for a given trajectory. The issues involve a proper representation of a trajectory, the choice of coordinates, determining control requirements for the trajectory for under-actuated as well as overactuated systems, and transferring controls from one set of actuators to another set of actuators during transition. The feasibility of the trajectory with respect to the available control power and airframe capability is another issue that has to be addressed. Further, we need to consider the problem of applying Inverse Dynamics for under-actuated system where more equations have to be satisfied than the number of control variables. In this paper we address all the above issues and present an example trajectory for AV-8B Harrier aircraft. 2000 by A. Verma and J.L. Junkins.