Designing autopilot system for fixed-wing flight mode of a tilt-rotor UAV in a virtual environment: X-Plane

Abstract

This paper describes an autopilot system design to regulate the altitude, heading and forward speed in the fixed-wing flight mode of the Osprey V22 VTOL (vertical takeoff and land) tilt rotor UAV accordingly to a reference, which is generated the trajectory sub-block. X- Plane flight simulator developed by Laminar Research, is used to test and optimize the parameter values of the autopilot system, which is designed using feedback, feedforward and PID controllers in MATLAB / Simulink environment (Software in the Loop- SIL). The receiver and sender blocks to perform the data interactions between MATLAB / Simulink and X-Plane flight simulator are created in MATLAB / Simulink environment. The receiver block is used to transfer data from the X-Plane flight simulator to the controller, while the sender block is used to transfer control signals from the controller to the X-Plane flight simulator program. The data communication between the two is UDP. The autopilot system under test is embedded in the Raspberry-Pi minicomputer and a hardware-in loop (HIL) test system created. The reaction of the control algorithm running on the Raspberry-Pi minicomputer to the virtual sensor data generated by the X-Plane flight simulator investigated. It is observed that, the Osprey-V22 aircraft can perform tasks autonomously in the horizontal flight mode, from the experiments and the results obtained. This study also describes the first stage of an undergoing project which aims to develop a robust autopilot for Osprey V22 VTOL UAV.