  Overactuated Tilt Rotor Unmanned Aerial Vehicles are renowned for exceptional
wind resistance and a broad operational range, which poses complex control
challenges due to non-affine dynamics. Traditional solutions employ multi-state
switched logic controllers for transitions. Our study introduces a novel
unified incremental nonlinear controller for overactuated dual-axis tilting
rotor quad-planes, seamlessly managing pitch, roll, and physical actuator
commands. The control allocation problem is addressed using a SQP iterative
optimization algorithm, well-suited for nonlinear actuator effectiveness in
thrust vectoring vehicles. The controller design integrates desired roll and
pitch angle inputs. These desired attitude angles are autonomously managed by
the controller and then conveyed to the vehicle during slow airspeed phases,
when the vehicle maintains its 6 DOF. We incorporate an AoA protection logic to
prevent wing stall and a yaw rate reference model for coordinated turns. Flight
tests confirm the controller's effectiveness in transitioning from hovering to
forward flight, achieving desired vertical and lateral accelerations, and
reverting to hovering.
