Science China Technological Sciences

, Volume 61, Issue 4, pp 516–521 | Cite as

Liquid metal spiral coil enabled soft electromagnetic actuator

  • Rui Guo
  • Lei Sheng
  • HengYi Gong
  • Jing Liu


Soft robot is a kind of machine form with flexible deformation capability. Making flexible actuators has recently become a hot research topic in the field. In this study, we demonstrated the facile fabrication of a soft electromagnetic actuator using liquid metal coil of Ga-In alloys, and designed several illustrative mechanical devices, such as jellyfish like robot, soft fishtail and flexible manipulator. Measurements of the liquid metal coil’s electrical properties confirmed that the liquid metal coil was mechanically stable under 48% uniaxial strains. Furthermore, the resistance of the liquid metal coil is stable under 60° bending deformation. Tests on the liquid metal coil’s driving properties confirmed that the liquid metal coil (55 mm×55 mm×1 mm) could reach the maximum displacement amplitude of 21.5 mm with the current of 0.48 A. It was shown that the electromagnetic interaction between the magnet and the liquid metal coil enables the coil as a highly efficient actuator. The mechanisms lying behind were interpreted and future applications of such system were discussed.


liquid metal soft machine electromagnetic actuator magnet artificial system 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Supplementary material

11431_2017_9063_MOESM1_ESM.mp4 (2.9 mb)
Supplementary material, approximately 2.91 MB.
11431_2017_9063_MOESM2_ESM.mp4 (8.7 mb)
Supplementary material, approximately 8.70 MB.
11431_2017_9063_MOESM3_ESM.mp4 (7.2 mb)
Supplementary material, approximately 7.15 MB.
11431_2017_9063_MOESM4_ESM.mp4 (6.4 mb)
Supplementary material, approximately 6.44 MB.


  1. 1.
    Kim S, Laschi C, Trimmer B. Soft robotics: A bioinspired evolution in robotics. Trends Biotech, 2013, 31: 287–294CrossRefGoogle Scholar
  2. 2.
    Rus D, Tolley M T. Design, fabrication and control of soft robots. Nature, 2015, 521: 467–475CrossRefGoogle Scholar
  3. 3.
    Martinez R V, Branch J L, Fish C R, et al. Robotic tentacles with three-dimensional mobility based on flexible elastomers. Adv Mater, 2013, 25: 205–212CrossRefGoogle Scholar
  4. 4.
    Martinez R V, Fish C R, Chen X, et al. Elastomeric origami: Programmable paper-elastomer composites as pneumatic actuators. Adv Funct Mater, 2012, 22: 1376–1384CrossRefGoogle Scholar
  5. 5.
    Shepherd R F, Stokes A A, Nunes R M D, et al. Soft machines that are resistant to puncture and that self seal. Adv Mater, 2013, 25: 6709–6713CrossRefGoogle Scholar
  6. 6.
    Li T, Keplinger C, Baumgartner R, et al. Giant voltage-induced deformation in dielectric elastomers near the verge of snap-through instability. J Mech Phys Solids, 2013, 61: 611–628CrossRefGoogle Scholar
  7. 7.
    Kofod G, Wirges W, Paajanen M, et al. Energy minimization for selforganized structure formation and actuation. Appl Phys Lett, 2007, 90: 081916CrossRefGoogle Scholar
  8. 8.
    Pelrine R, Kornbluh R, Pei Q, et al. High-speed electrically actuated elastomers with strain greater than 100%. Science, 2000, 287: 836–839CrossRefGoogle Scholar
  9. 9.
    Foroughi J, Spinks G M, Wallace G G, et al. Torsional carbon nanotube artificial muscles. Science, 2011, 334: 494–497CrossRefGoogle Scholar
  10. 10.
    Haines C S, Lima M D, Li N, et al. Artificial muscles from fishing line and sewing thread. Science, 2014, 343: 868–872CrossRefGoogle Scholar
  11. 11.
    Kwok S W, Morin S A, Mosadegh B, et al. Magnetic assembly of soft robots with hard components. Adv Funct Mater, 2014, 24: 2180–2187CrossRefGoogle Scholar
  12. 12.
    Kim S H, Hashi S, Ishiyama K. Magnetic actuation based snake-like mechanism and locomotion driven by rotating magnetic field. IEEE Trans Magn, 2011, 47: 3244–3247CrossRefGoogle Scholar
  13. 13.
    Choi H, Jeong S, Lee C, et al. Biomimetic swimming mini-robots using electro-magnetic actuation (EMA) system. In: 12th International Conference on Control, Automation and Systems (ICCAS). JeJu Island: IEEE, 2012. 1923–1926Google Scholar
  14. 14.
    Mengüç Y, Park Y L, Pei H, et al. Wearable soft sensing suit for human gait measurement. Int J Robot Res, 2014, 33: 1748–1764CrossRefGoogle Scholar
  15. 15.
    Jin C, Zhang J, Li X, et al. Injectable 3-D fabrication of medical electronics at the target biological tissues. Sci Rep, 2013, 3: 3442CrossRefGoogle Scholar
  16. 16.
    Yu Y, Zhang J, Liu J. Biomedical implementation of liquid metal ink as drawable ecg electrode and skin circuit. PLoS ONE, 2013, 8: e58771CrossRefGoogle Scholar
  17. 17.
    Gao Y, Li H, Liu J. Directly writing resistor, inductor and capacitor to composite functional circuits: A super-simple way for alternative electronics. PLoS ONE, 2013, 8: e69761CrossRefGoogle Scholar
  18. 18.
    Zheng Y, He Z, Gao Y, et al. Direct desktop printed-circuits-on-paper flexible electronics. Sci Rep, 2013, 3: 1786CrossRefGoogle Scholar
  19. 19.
    Guo C, Yu Y, Liu J. Rapidly patterning conductive components on skin substrates as physiological testing devices via liquid metal spraying and pre-designed mask. J Mater Chem B, 2014, 2: 5739–5745CrossRefGoogle Scholar
  20. 20.
    Bauer S, Bauer-Gogonea S, Graz I, et al. 25th Anniversary article: A soft future: From robots and sensor skin to energy harvesters. Adv Mater, 2014, 26: 149–162CrossRefGoogle Scholar
  21. 21.
    Park Y L, Majidi C, Kramer R, et al. Hyperelastic pressure sensing with a liquid-embedded elastomer. J Micromech Microeng, 2010, 20: 125029CrossRefGoogle Scholar
  22. 22.
    Fassler A, Majidi C. Soft-matter capacitors and inductors for hyperelastic strain sensing and stretchable electronics. Smart Mater Struct, 2013, 22: 055023CrossRefGoogle Scholar
  23. 23.
    Lazarus N, Meyer C D, Bedair S S, et al. Multilayer liquid metal stretchable inductors. Smart Mater Struct, 2014, 23: 085036CrossRefGoogle Scholar
  24. 24.
    Jin S W, Park J, Hong S Y, et al. Stretchable loudspeaker using liquid metal microchannel. Sci Rep, 2015, 5: 11695CrossRefGoogle Scholar

Copyright information

© Science China Press and Springer-Verlag GmbH Germany, part of Springer Nature 2017

Authors and Affiliations

  1. 1.Department of Biomedical Engineering, School of MedicineTsinghua UniversityBeijingChina
  2. 2.Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijingChina

Personalised recommendations