Multidisciplinary Design Optimization for an Electric Quadrotor Fixed-Wing Hybrid Unmanned Air Vehicle

This paper addresses issues in the current design of electric quadrotor fixed-wing hybrid unmanned air vehicles(EH-UAVs), including a lack of theoretical basis for the layout configuration selection, a lack of analysis and evaluation methods for the wind disturbance rejection capability in the quadrotor mode, the issue that design methods for the electric propulsion systems of most EH-UAVs are to design the quadrotor system and fixed-wing system independently, and the issue that design methods for the conceptual design are mainly the traditional sequence design methods without fully considering the complex coupling relationships caused by the mutual transfer of parameters between various disciplines such as geometric shape, aerodynamics, trimming and stability, propulsion system, weight, wind disturbance rejection capability in the quadrotor mode, and endurance performance. Based on the proposed improved surrogate model based concurrent subspace optimization(CSSO)architecture, this paper establishes a multidisciplinary optimization(MDO)method for the conceptual design of EH-UAVs. This is accomplished by building geometric shape parameterization models and aerodynamic grid division models, aerodynamic and flight performance analysis models for different flight modes, evaluation and analysis models for wind disturbance rejection capability in the quadrotor mode, and the proposed electric propulsion system models. The proposed MDO method and the discipline analysis models are applied to the conceptual design process of a small EH-UAV. A prototype of the EH-UAV is fabricated based on the MDO results. The flight test results of the prototype show that the flight performance meets the design requirements, and with a 2.8% reduction in takeoff weight, the endurance time is improved by approximately 14.1%, and the maximum wind speed that the EH-UAV can resist is increased by approximately 3.5%. This verifies the feasibility and correctness of the MDO method proposed in this article, which can provide guidance for the research and application of EH-UAVs. © 2023 Xi'an Jiaotong University. All rights reserved.