Autonomous Flight Control System for Engine Testing

Abstract

This research presents the development of an Autonomous Flight Control System (AFCS) for the Kestrel, a fixed-wing unmanned aerial vehicle designed by Greenjets as a flying test bench for engine performance evaluation. A Six-Degrees of Freedom (6DoF) model was developed to simulate the Kestrel’s motion, incorporating aerodynamic forces, stability derivatives, and thrust effects. Aerodynamic and stability coefficients were extracted by the vortex lattice method using OpenVSP simulations, forming the foundation for modelling and control design. A Flight Control System (FCS) was implemented using a three-loop nested architecture: an inner loop for pitch and roll rate stabilisation, a middle loop for attitude and airspeed regulation, and closing with an outer loop for course angle and altitude control. Simulations demonstrated the system’s capability to achieve stable responses of commanded flight inputs, with coordinated use of ailerons and elevons in the absence of yaw control. Results reveal the effectiveness of the developed model and control system in enabling autonomous flight, providing a structured foundation for future integration with real-world testing and higherfidelity validation.