Challenges for 100 Milligram Flapping Flight

  • Ronald S. FearingEmail author
  • Robert J. Wood


Creating insect-scale flapping flight at the 0.1 gram size has presented significant engineering challenges. A particular focus has been on creating miniature machines which generate similar wing stroke kinematics as flies or bees. Key challenges have been thorax mechanics, thorax dynamics, and obtaining high power-to-weight ratio actuators. Careful attention to mechanical design of the thorax and wing structures, using ultra-high-modulus carbon fiber components, has resulted in high-lift thorax structures with wing drive frequencies at 110 and 270 Hz. Dynamometer characterization of piezoelectric actuators under resonant load conditions has been used to measure real power delivery capability. With currently available materials, adequate power delivery remains a key challenge, but at high wingbeat frequencies, we estimate that greater than 400 W/kg is available from PZT bimorph actuators. Neglecting electrical drive losses, a typical 35% actuator mass fraction with 90% mechanical transmission efficiency would yield greater than 100 W/kg wing shaft power. Initially the micromechanical flying insect (MFI) project aimed for independent control of wing flapping and rotation using two actuators per wing. At resonance of 270 Hz, active control of a 2 degrees of freedom wing stroke requires precise matching of all components. Using oversized actuators, a bench top structure has demonstrated lift greater than 1000 \(\upmu\)N from a single wing. Alternatively, the thorax structure can be drastically simplified by using passive wing rotation and a single-drive actuator. Recently, a 60 mg flapping-wing robot using passive wing rotation has taken off for the first time using external power and guide rails.


Piezoelectric Actuator Flexure Hinge Insect Wing Wing Motion Indirect Flight Muscle 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The authors acknowledge the key work of collaborators S. Avadhanula and E. Steltz on thorax and actuator design and characterization. Portions of this work were supported by NSF IIS-0412541. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).


  1. 1.
    Altshuluer, D., Dickson, W., Vance, J., Roberts, S., Dickinson, M.: Short-amplitude high-frequency wing strokes determine the aerodynamics of honeybee flight. Proceedings of the National Academy of Sciences (USA) 102, 18, 213–18, 218 (2005)Google Scholar
  2. 2.
    Avadhanula, S., Wood, R., Campolo, D., Fearing, R.: Dynamically tuned design of the MFI thorax. IEEE International Conference on Robotics and Automation. Washington, DC (2002)Google Scholar
  3. 3.
    Avadhanula, S., Wood, R.J., Steltz, E., Yan, J., Fearing, R.S.: Lift force improvements for the micromechanical flying insect. IEEE/RSJ International Conference on Intelligent Robots and Systems, 2007 IROS 2007 (Oct. 28–30, 2003)Google Scholar
  4. 4.
    Campolo, D., Sitti, M., Fearing, R.: Efficient charge recovery method for driving piezoelectric actuators in low power applications. IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control 50, 237–244 (Mar. 2003)CrossRefGoogle Scholar
  5. 5.
    Combes, S., Daniel, T.: Flexural stiffness in insect wings I. Scaling and the influence of wing venation. Journal of Experimental Biology 206 (17), 2979–2987 (2003)CrossRefGoogle Scholar
  6. 6.
    Combes, S., Daniel, T.: Flexural stiffness in insect wings II. Spacial distribution and dynamic wing bending. Journal of Experimental Biology 206 (17), 2989–2997 (2003)CrossRefGoogle Scholar
  7. 7.
    Deng, X., Schenato, L., Sastry, S.: Model identification and attitude control for a micromechanical flying insect including thorax and sensor models. IEEE Int. Conf. on Robotics and Automation. Taipei, Taiwan (2003)Google Scholar
  8. 8.
    Dickinson, M., Lehmann, F.O., Sane, S.: Wing rotation and the aerodynamic basis of insect flight. Science 284, 1954–1960 (1999)CrossRefGoogle Scholar
  9. 9.
    Dickinson, M., Tu, M.: The function of dipteran flight muscle. Comparative Biochemistry and Physiology vol. 116A, pp. 223–238 (1997)CrossRefGoogle Scholar
  10. 10.
    Dudley, R.: The Biomechanics of Insect Flight: Form, Function and Evolution. Princeton University Press (1999)Google Scholar
  11. 11.
    Ebefors, T., Mattsson, J., Kälvesten, E., Stemme, G.: A walking silicon micro-robot. The 10th Int. Conf. on Solid-State Sensors and Actuators (Transducers ’99), pp. 1202–1205. Sendai, Japan (1999)Google Scholar
  12. 12.
    Ennos, A.: The inertial cause of wing rotation in Diptera. Journal of Experimental Biology 140, 161–169 (1988)Google Scholar
  13. 13.
    Miyan, J., Ewing, A.: How Diptera move their wings: A re-examination of the wing base articulation and muscle systems concerned with flight. Philosophical Transactions of the Royal Society of London B311, 271–302 (1985)CrossRefGoogle Scholar
  14. 14.
    Steltz, E., Avadhanula, S., Fearing, R.: High lift force with 275 hz wing beat in MFI. IEEE/RSJ Int. Conf. on Intelligent Robots and Systems. IROS 2007. pp. 3987–3992 (October 29 2007–November 2 2007)Google Scholar
  15. 15.
    Steltz, E., Avadhanula, S., Wood, R., Fearing, R.: Characterization of the micromechanical flying insect by optical position sensing. IEEE International Conference on Robotics and Automation. Barcelona, Spain (2005)Google Scholar
  16. 16.
    Steltz, E., Fearing, R.: Dynamometer power output measurements of piezoelectric actuators. IEEE/RSJ Int. Conf. on Intelligent Robots and Systems. IROS 2007. pp. 3980–3986 (October 29 2007–November 2 2007)Google Scholar
  17. 17.
    Sunada, S., Ellington, C.: A new method for explaining the generation of aerodynamic forces in flapping flight. Mathematical Methods in the Applied Sciences 24, 1377–1386 (2001)zbMATHCrossRefGoogle Scholar
  18. 18.
    Wang, Z., Birch, J., Dickinson, M.: Unsteady forces and flows in low reynolds number hovering flight: two-dimensional computations vs robotic wing experiments. Journal of Experimental Biology 207, 449–460 (2004)CrossRefGoogle Scholar
  19. 19.
    Wood, R.: Design, fabrication, and analysis of a 3dof, 3 cm flapping-wing MAV. IEEE/RSJ Int. Conf. on Intelligent Robots and Systems, 2007. IROS 2007. pp. 1576–1581 (October 29 2007-November 2 2007)Google Scholar
  20. 20.
    Wood, R., Avadhanula, S., Menon, M., Fearing, R.: Microrobotics using composite materials: The micromechanical flying insect thorax. IEEE Int. Conf. on Robotics and Automation. Taipei, Taiwan (2003)Google Scholar
  21. 21.
    Wood, R., Avadhanula, S., Sahai, R., Steltz, E., Fearing, R.: Microrobot design using fiber reinforced composites. Journal of Mech. Design 130 (5) (2008)Google Scholar
  22. 22.
    Wood, R., Steltz, E., Fearing, R.: Optimal energy density piezoelectric bending actuators. Journal of Sensors and Actuators A: Physical 119 (2), 476–488 (2005)CrossRefGoogle Scholar
  23. 23.
    Yeh, R., Kruglick, E., Pister, K.: Surface-micromachined components for articulated microrobots. Journal of Microelectrical Mechanical Systems 5 (1), 10–17 (1996)CrossRefGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2009

Authors and Affiliations

  1. 1.Biomimetic Millisystems LabUniv. of CaliforniaBerkeleyUSA
  2. 2.Harvard Microrobotics LaboratoryHarvard UniversityCambridgeUSA

Personalised recommendations