Multidisciplinary Design Optimization of the Vertical Takeoff and Landing for Fixed-Wing Hybrid Unmanned Aerial Vehicles

Vertical takeoff and landing (VTOL) fixed-wing hybrid unmanned aerial vehicle is currently the most noteworthy and practical solution for VTOL fixed-wing aircraft. However, several issues persist in existing electric fixed-wing hybrid unmanned aerial vehicle (EHUAV) design methods. These issues include the absence of a theoretical foundation for selecting layout configurations, a lack of analysis methods for wind disturbance rejection capability in quadrotor mode, and the tendency to design electric propulsion systems independently for the quadrotor and fixed-wing systems. Moreover, traditional sequence design methods dominate the conceptual design process. To address these issues, this study proposes a multidisciplinary design optimization (MDO) method for EHUAVs. The research delves into methods for geometric shape parametric modeling, aerodynamic grid generation, aerodynamic performance analysis, flight performance analysis, wind disturbance rejection capability analysis in quadrotor mode, and electric propulsion systems analysis for EHUAVs. The developed MDO method and discipline analysis methods are applied to the conceptual design of a small EHUAV. A prototype is constructed based on the MDO results. The flight tests show that the error in endurance time is approximately 1.02% compared to the MDO results, the error in the maximum wind speed the EHUAV can withstand during VTOL process is about 2.2%, and the flight speed in each flight phase aligns with the design requirement. The findings not only confirm the feasibility and accuracy of the proposed MDO methods but also contribute to advancing the design methodologies for EHUAVs.