Multicopter Aerodynamics: Characterizing Thrust on a Hexacopter

Visão Geral

Source: Prashin Sharma and Ella M. Atkins, Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI

Multicopters are becoming popular for a variety of hobby and commercial applications. They are commonly available as quadcopter (four thrusters), hexacopter (six thrusters), and octocopter (eight thrusters) configurations. Here, we describe an experimental process to characterize the multicopter performance. A modular small hexacopter platform providing propulsion unit redundancy is tested. The individual static motor thrust is determined using a dynamometer and varying propeller and input commands. This static thrust is then represented as a function of motor RPM, where the RPM is determined from motor power and control input. The hexacopter is then mounted on a load cell test stand in a 5’ x 7’ low-speed recirculating wind tunnel, and its aerodynamic lift and drag force components were characterized during flight at varying motor signals, free-stream flow speed, and angle of attack.

A hexacopter was selected for this study because of its resilience to motor (propulsion unit) failure, as reported in Clothier1. Along with redundancy in the propulsion system, the selection of high-reliability components is also required for safe flight, particularly for missions over-populated regions. In Ampatis2, the authors discuss the optimal selection of multicopter parts, such as motors, blades, batteries, and electronic speed controllers. Similar research has also been reported in Bershadsky3, which focuses on the proper selection of a propeller system to satisfy mission requirements. Along with redundancy and reliability of components, understanding vehicle performance is also essential to assure flight envelope limits are respected and to select the most efficient design.

Procedimento

This protocol characterizes hexacopter thrust and aerodynamics. For this experiment, we used commercially available, off-the-shelf components for the hexacopter, and the details are provided in Table 2. For the flight controller, we selected an open-source autopilot, Librepilot,9 as it provided flexibility to control individual motor commands issued to the hexacopter.  

The test stand for mounting the load cell and hexacopter was fabricated in-house using laminated plywood

Log in or to access full content. Learn more about your institution’s access to JoVE content here

Resultados

Dynamometer Tests

In Figures 5-6, the plots illustrate the variation of thrust and torque, respectively, with increasing motor RPM. From these plots, the minimum motor RPM required for the multicopter to hover can be determined. A plot showing data from multiple propellers can be obtained from Sharma12. Further, the quadratic relations between thrust vs. RPM and moment vs. RPM can be clearly observed, which are described in Equations (1) and (2). Using this

Log in or to access full content. Learn more about your institution’s access to JoVE content here

Aplicação e Resumo

Here we describe a protocol to characterize the aerodynamic forces acting on a hexacopter. This protocol can be applied to other multirotor configurations directly. Proper characterization of aerodynamic forces is needed to improve control design, understand flight envelope limits, and estimate local wind fields as in Xiang13. The presented protocol for determining motor RPM based on power consumption and throttle command has direct applications to estimate RPM and thrust when low-cost electronic speed control

Log in or to access full content. Learn more about your institution’s access to JoVE content here

Referências
  1. Clothier, R.A., and Walker, R.A., “Safety Risk Management of Unmanned Aircraft Systems,” Handbook  of Unmanned Aerial Vehicles, Springer, 2015, pp. 2229–2275.
  2. Ampatis, C., and Papadopoulos, E., “Parametric Design and Optimization of Multi-rotor Aerial Vehicles,” Applications of Mathematics and Informatics in Science and Engineering, Springer, 2014, pp. 1–25. 

  3. Bershadsky, D., Haviland, S., and Johnson, E. N., “Electric Multirotor UAV Propulsion System Sizing for Performance Prediction and Design Optimization,” 57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conf., 2016.
  4. Bangura, M., Melega, M., Naldi, R., and Mahony, R., “Aerodynamics of Rotor Blades for Quadrotors,” arXiv preprint arXiv:1601.00733, 2016
  5. Ducard, G., and Minh-Duc Hua. "Discussion and Practical Aspects on Control Allocation for a Multi-rotor Helicopter." Conf. on Unmanned Aerial Vehicle in Geomatics, 2011.
  6. Powers C., Mellinger D., Kumar V. “Quadrotor Kinematics and Dynamics” In: Handbook of Unmanned Aerial Vehicles. Springer, 2015
  7. McClamroch, N. Harris. “Steady Aircraft Flight and Performance.” Princeton University Press, 2011.
  8. Quan, Q., “Introduction to Multicopter Design and Control”, Springer Singapore, 2017.
  9. LibrePilot, https://www.librepilot.org/site/index.html
  10. Foster, J. and Hartman, D., “High-Fidelity Multi-Rotor Unmanned Aircraft System Simulation Development for Trajectory Prediction under Off-Nominal Flight Dynamics,” Proc. Air Transportation Integration & Operations (ATIO) Conference, AIAA, 2017. 
  11. Russell, Carl R., et al. "Wind Tunnel and Hover Performance Test Results for Multicopter UAS Vehicles," 2016.
  12. Sharma, P. and Atkins, E., “An Experimental Investigation of Tractor and Pusher Hexacopter Performance,” Proc. AIAA Aviation Conference, AIAA, June 2018. (to appear)
  13. Xiang, X., et al. "Wind Field Estimation through Autonomous Quadcopter Avionics." 35th AIAA/IEEE Digital Avionics Systems Conference (DASC), IEEE, 2016.
  14. Kamel, M., et al. "Model Predictive Control for Trajectory Tracking of Unmanned Aerial Vehicles using Robot Operating System." Robot Operating System (ROS). Springer, Cham, 2017, 3-39.
Tags
MulticoptersAerodynamicsThrustHexacopterRotorsPitch ControlFlight ControlPropellersHoverAttitudeAxesPitch AxisRoll AxisYaw AxisThrust DifferentialForward MovementSide to side MovementYaw ControlHeading Angle

Pular para...

0:01

Concepts

3:01

Dynamometer Experiment

4:18

Static Text

5:51

Dynamic Thrust Test

7:57

Results

Vídeos desta coleção:

article

Now Playing

Multicopter Aerodynamics: Characterizing Thrust on a Hexacopter

Aeronautical Engineering

9.0K Visualizações

article

Desempenho Aerodinâmico de um Aeromodelo: O DC-6B

Aeronautical Engineering

8.1K Visualizações

article

Caracterização da hélice: variações no passo, diâmetro e número de pás no desempenho

Aeronautical Engineering

26.0K Visualizações

article

Comportamento do aerofólio: Distribuição de pressão sobre uma asa Clark Y-14

Aeronautical Engineering

20.8K Visualizações

article

Desempenho da asa Clark Y-14: Implantação de dispositivos de alta sustentação (Flaps e Slats)

Aeronautical Engineering

13.2K Visualizações

article

Método da esfera de turbulência: avaliando a qualidade do fluxo do túnel de vento

Aeronautical Engineering

8.6K Visualizações

article

Fluxo Cilíndrico Cruzado: Medição da Distribuição de Pressão e Estimando os Coeficientes de Arrasto

Aeronautical Engineering

16.0K Visualizações

article

Análise de bocais: variações no número de Mach e na pressão ao longo de um bocal convergente e convergente-divergente

Aeronautical Engineering

37.7K Visualizações

article

Imageamento de Schlieren: uma técnica para visualizar recursos de fluxo supersônico

Aeronautical Engineering

11.2K Visualizações

article

Visualização de fluxo em um túnel de água: observando o vórtice de ponta sobre uma asa delta

Aeronautical Engineering

7.8K Visualizações

article

Visualização de fluxo com corante de superfície: um método qualitativo para observar padrões de estrias em fluxo supersônico

Aeronautical Engineering

4.8K Visualizações

article

Tubo Pitot-estático: um dispositivo para medir a velocidade do fluxo de ar

Aeronautical Engineering

48.4K Visualizações

article

Anemometria de temperatura constante: uma ferramenta para estudar o fluxo em camada limite turbulenta

Aeronautical Engineering

7.1K Visualizações

article

Transdutor de Pressão: Calibração Usando um Tubo Pitot-estático

Aeronautical Engineering

8.4K Visualizações

article

Controle de Voo em Tempo Real: Calibração de Sensor Incorporado e Aquisição de Dados

Aeronautical Engineering

10.0K Visualizações

JoVE Logo

Privacidade

Termos de uso

Políticas

Pesquisa

Educação

SOBRE A JoVE

Copyright © 2025 MyJoVE Corporation. Todos os direitos reservados