Multidisciplinary design optimization of an electric propulsion system of a hybrid UAV considering wind disturbance rejection capability in the quadrotor mode

Abstract

The electric propulsion system (EPS) of a quadrotor fixed-wing hybrid unmanned aerial vehicle (QFHUAV) has important effects on its time of endurance and wind disturbance rejection capability in the quadrotor mode. Currently, the design methods of most QFHUAV EPSs are to design the quadrotor propulsion system and fixed-wing propulsion system independently. The wind disturbance rejection capability in the quadrotor mode is not considered in these methods. The multidisciplinary design optimization (MDO) method can reduce design time and cost by integrating all the disciplines involved in the design process. The MDO solutions are generally more optimal with respect to standard optimal sequential solutions. This paper proposes an MDO for a QFHUAV EPS considering the wind disturbance rejection capability in the quadrotor mode. The analysis modules of the propeller/rotor discipline, brushless direct current motor discipline, electronic speed control discipline, lithium polymer battery discipline, time of endurance discipline, mass discipline, and wind disturbance rejection capability in the quadrotor mode discipline are modeled. The MDO process of a QFHUAV EPS is constructed according to the transfer process and coupling relations among the discipline parameters. Based on the mission profile, the flight performance and mission requirements of the QFHUAV are created and a multi-objective optimization design model of the QFHUAV EPS is modeled. The Multidisciplinary feasible approach is implemented to decompose the mass coupling variables between the EPS component analysis modules and the mass analysis module effectively. A multi-objective evolutionary algorithm named NSGA-II is used to discover the full Pareto front for the multi-objective problem. The proposed MDO method is used to design the EPS of a self-developed QFHUAV. The optimal combination of QFHUAV EPS components is determined based on the optimization results. A comparison between the optimization results and the actual flight performance of the QFHUAV shows that the flight performance is in good agreement with the optimization results, which indicates that the MDO method proposed in this paper is feasible and reasonable.