Enhancing Multirotor Drone Efficiency: Exploring Minimum Energy Consumption Rate of Forward Flight under Varying Payload

TL;DR

This paper analytically and numerically demonstrates that the optimal energy efficiency index for multirotor drones remains constant across different payloads when flying at the velocity that minimizes energy consumption, aiding in flight optimization.

Contribution

It introduces a novel analytical proof that the energy efficiency index's optimum is constant under varying payloads at the optimal velocity, supported by validation studies.

Findings

Optimal energy per meter per unit mass is constant across payloads.

Optimal pitch angle remains constant at optimal velocity.

Validation confirms analytical predictions.

Abstract

Multirotor unmanned aerial vehicle is a prevailing type of aircraft with wide real-world applications. Energy efficiency is a critical aspect of its performance, determining the range and duration of the missions that can be performed. In this study, we show both analytically and numerically that the optimum of a key energy efficiency index in forward flight, namely energy per meter traveled per unit mass, is a constant under different vehicle mass (including payload). Note that this relationship is only true under the optimal forward velocity that minimizes the energy consumption (under different mass), but not under arbitrary velocity. The study is based on a previously developed model capturing the first-principle energy dynamics of the multirotor, and a key step is to prove that the pitch angle under optimal velocity is a constant. By employing both analytical derivation and validation studies, the research provides critical insights into the optimization of multirotor energy efficiency, and facilitate the development of flight control strategies to extend mission duration and range.