Integrated flight/thrust vectoring control for jet-powered unmanned aerial vehicles with ACHEON propulsion

As a new alternative to tilting rotors or turbojet vector mechanical oriented nozzles, ACHEON (Aerial Coanda High Efficiency Orienting-jet Nozzle) has enormous advantages because it is free of moving elements and highly effective for vertical/short-take-off and landing (V/STOL) aircraft. In this article, an integrated flight/thrust vectoring (TV) control scheme for a jet-powered unmanned aerial vehicle (UAV) with an ACHEON nozzle is proposed to assess its suitability in jet aircraft flight applications. First, a simplified TV population model is built based on CFD simulation data and parameter identification. Second, this TV propulsion model is embedded as a jet actuator for a benchmark fixed-wing ‘Aerosonde’ UAV, and then a four ‘cascaded-loop’ controller, based on nonlinear dynamic inversion (NDI), is designed to individually control the angular rates (in the body frame), attitude angles (in the wind frame), track angles (in the navigation frame), and position (in the earth-centred frame) . Unlike previous research on fixed-wing UAV flight controls or TV controls, our proposed four-cascaded NDI control law can not only coordinate surface control and TV control as well as an optimization controller, but can also implement an absolute self-position control for the autopilot flight control. Finally, flight simulations in a high-fidelity aerodynamic environment are performed to demonstrate the effectiveness and superiority of our proposed control scheme.