Development of a dynamic model of a ducted fan VTOL UAV
Creators: name: Zhao, Huiwen
Publisher: name: RMIT University
Year: 2024

description: The technology of UAV (Unmanned Aerial Vehicle) has developed since its conception many years ago. UAVs have several features such as, computerised and autonomous control without the need for an on-board pilot. Therefore, there is no risk of loss of life and they are easier to maintain than manned aircraft. In addition, UAVs have an extended range/endurance capability, sometimes for several days. This makes UAVs attractive for missions that are typically 'dull, dirty and dangerous'. With the development of technology, the application of UAVs is becoming commonplace for both military and civil missions. Examples of this are reconnaissance, surveillance, environmental monitoring, disaster observation, etc.<br><br>The School of Aerospace, Mechanical and Manufacturing Engineering (SAMME) at RMIT University has designed a novel concept for a ducted-fan UAV with vertical takeoff and landing capability and the option to transition to horizontal flight. The aerodynamic analysis, preliminary and detailed design, of this ducted-fan VTOL UAV, is the first and most important step. To optimize the aerodynamic characteristics, evaluating aerodynamic coefficients and analyzing the flow patterns around the vehicle at different speeds and angles of attack is necessary. In this project, CFD plays an important role in predicting the longitudinal and lateral stability and control characteristics of a full-scale model of ducted fan VTOL UAV at both vertical and horizontal flight without any prior knowledge of existing wind tunnel or flight test data. <br><br>Prior to carrying out experiments in the wind tunnel, the manufacture of ducted fan VTOL UAV was focused on. Particular attention was paid to the propulsion system as the key point. The full-scale model of UAV was produced using the Rapid Prototyping Facility at SAMME to ensure its accurate geometric shape for testing in the wind tunnel. <br><br>The experiments of the full-scale UAV model with engines was conducted in RMIT's Industrial Wind Tunnel where its aerodynamic characteristics and its properties of counter-rotating propulsion system were tested. In addition, the correlation between experimental data and CFD results was evaluated and the accuracy of the dynamic model of ducted fan VTOL UAV was improved. <br><br>Flight dynamics is concerned with the motion of an aircraft due to internally or externally generated forces. The ducted fan VTOL UAV stability and control derivatives are determined and used as a basis in a flight simulation environment. This simulation showed that the vehicle is stable and controllable for a range of flight speeds. <br><br>Finally, a MIMO linear control system was designed to control the vehicle in hovering and low-speed slide flight. The real-time simulation and modeling in MATLAB combined with a flight-simulator showed several animations and trajectories of UAV missions with or without crosswind effect during flight. These simulations were very helpful in determining the dynamic behaviour of the vehicle under various flight conditions.