Mission-oriented performance assessment and optimization of electric multirotors

Abstract

In recent years, the technical advancement of electric propulsion systems has contributed to the growing applicability of multirotor-type unmanned aerial vehicles from personal hobbies to industrial fields. Industrial fields involve various mission profiles comprising several mission-legs, such as hover and forward flight. Thus, enhancing the applicability of multirotors requires them to be designed for specific mission profiles. This paper presents systematic design and analysis methods for realizing the optimum design of multirotors carrying out user-defined missions. To this end, we integrate a newly developed analysis algorithm for the electric propulsion system, which allows accurate performance assessment according to the combination of the components and flight conditions. Further, a practical drag model is developed for the estimation of drag force during forward flight, where the drag force affects the performance of the entire mission. In addition, a frame weight model is proposed to achieve reliable design results in the conceptual design phase. These models and algorithm constitute a design framework named as CLOUDS. Finally, an exemplary optimization problem is formulated and solved for a generic delivery mission profile. The optimal configurations depending on the number of rotors are obtained using Genetic Algorithm. The optimization results clearly demonstrate the necessity and efficacy of the presented methods, algorithm, and models for designing mission-oriented multirotors in the conceptual design phase.