Multi-Outer Loop Dynamic Inversion Control: An Application to a VTOL Free-Wing Aircraft

This letter extends a typical series cascade control structure to an N-outer loop system applicable to coupled rigid body systems, including a VTOL free-wing aircraft. In this case, there are now external command signals from multiple, outer subsystems that are designed simultaneously for a single inner subsystem. For example, in the case of the VTOL free-wing aircraft, the standard outer loop modifies the wing pitch attitude command to achieve the desired position and velocity, and a newly implemented 'swing loop' also modifies the wing pitch attitude command to dampen fuselage pitch attitude oscillations. The proposed multi-outer loop dynamic inversion architecture is successful in the autonomous control of a 3-loop VTOL free-wing aircraft with both simulation and flight test results presented.