JACIII Vol.27 No.2 pp. 235-242
doi: 10.20965/jaciii.2023.p0235


Modeling and Control Strategies for Liquid Crystal Elastomer-Based Soft Robot Actuator

Jundong Wu*1,*2,*3 ORCID Icon, Yawu Wang*1,*2,*3 ORCID Icon, Wenjun Ye*4 ORCID Icon, Jinhua She*5 ORCID Icon, and Chun-Yi Su*4,† ORCID Icon

*1School of Automation, China University of Geosciences
388 Lumo Road, Hongshan District, Wuhan 430074, China

*2Hubei Key Laboratory of Advanced Control and Intelligent Automation for Complex Systems
Wuhan , China

*3Engineering Research Center of Intelligent Technology for Geo-Exploration, Ministry of Education
Wuhan , China

*4Gina Cody School of Engineering and Computer Science, Concordia University
1455 De Maisonneuve Blvd. W. Montreal, Quebec H 1, Canada

Corresponding author

*5School of Engineering, Tokyo University of Technology
1404-1 Katakuramachi, Hachioji, Tokyo 192-0982, Japan

November 12, 2022
November 28, 2022
March 20, 2023
liquid crystal elastomer, soft robot actuator, modeling, control, hysteresis

Liquid crystal elastomer is a type of soft material with unique physical and chemical properties that offer a variety of possibilities in the growing field of soft robot actuators. This type of material is able to exhibit large, revertible deformation under various external stimuli, including heat, electric or magnetic fields, light, etc., which may lead to a wide range of different applications such as bio-sensors, artificial muscles, optical devices, solar cell plants, etc. With these possibilities, it is important to establish modeling and control strategies for liquid crystal elastomer-based actuators, to obtain the accurate prediction and description of its physical dynamics. However, so far, existing studies on this type of the actuators mainly focus on material properties and fabrication, the state of art on the modeling and control of such actuators is still preliminary. To gain a better understanding on current studies of the topic from the control perspective, this review provides a brief collection on recent studies on the modeling and control of the liquid crystal elastomer-based soft robot actuator. The review will introduce the deformation mechanism of the actuator, as well as basic concepts. Existing studies on the modeling and control for the liquid crystal elastomer-based actuator will be organized and introduced to provide an overview in this field as well as future insights.

Cite this article as:
J. Wu, Y. Wang, W. Ye, J. She, and C. Su, “Modeling and Control Strategies for Liquid Crystal Elastomer-Based Soft Robot Actuator,” J. Adv. Comput. Intell. Intell. Inform., Vol.27 No.2, pp. 235-242, 2023.
Data files:
  1. [1] C. Majidi, “Soft robotics: a perspective current trends and prospects for the future,” Soft Robotics, Vol.1, No.1, pp. 5-11, 2014.
  2. [2] C. Lee, M. Kim, Y. J. Kim, N. Hong, S. Ryu, H. J. Kim, and S. Kim, “Soft robot review,” Int. J. of Control, Automation and Systems, Vol.15, No.1, pp. 3-15, 2017.
  3. [3] H. Wang, M. Totaro, and L. Beccai, “Toward perceptive soft robots: Progress and challenges,” Advanced Science, Vol.5, No.9, Article No.1800541, 2018.
  4. [4] D. Trivedi, C. D. Rahn, W. M. Kier, and I. D. Walker, “Soft robotics: Biological inspiration, state of the art, and future research,” Applied Bionics and Biomechanics, Vol.5, Article No.520417, 2008.
  5. [5] D. Rus and M. T. Tolley, “Design, fabrication and control of soft robots,” Nature, Vol.521, No.7553, pp. 467-475, 2015.
  6. [6] P. Ohta, L. Valle, J. King, K. Low, J. Yi, C. G. Atkeson, and Y.-L. Park, “Design of a lightweight soft robotic arm using pneumatic artificial muscles and inflatable sleeves,” Soft Robotics, Vol.5, No.2, pp. 204-215, 2018.
  7. [7] M. Wehner, R. L. Truby, D. J. Fitzgerald, B. Mosadegh, G. M. Whitesides, J. A. Lewis, and R. J. Wood, “An integrated design and fabrication strategy for entirely soft, autonomous robots,” Nature, Vol.536, No.7617, pp. 451-455, 2016.
  8. [8] W.-B. Li, W.-M. Zhang, H.-X. Zou, Z.-K. Peng, and G. Meng, “A fast rolling soft robot driven by dielectric elastomer,” IEEE/ASME Trans. on Mechatronics, Vol.23, No.4, pp. 1630-1640, 2018.
  9. [9] Y. Kim, H. Yuk, R. Zhao, S. A. Chester, and X. Zhao, “Printing ferromagnetic domains for untethered fast-transforming soft materials,” Nature, Vol.558, No.7709, pp. 274-279, 2018.
  10. [10] M. Sfakiotakis, A. Kazakidi, and D. Tsakiris, “Octopus-inspired multi-arm robotic swimming,” Bioinspiration & Biomimetics, Vol.10, No.3, Article No.035005, 2015.
  11. [11] C. Laschi and M. Cianchetti, “Soft robotics: New perspectives for robot bodyware and control,” Frontiers in Bioengineering and Biotechnology, Vol.2, Article No.3, 2014.
  12. [12] M. Bengisu and M. Ferrara, “Materials that move: Smart materials, intelligent design,” Springer, 2018.
  13. [13] N. Bira, P. Dhagat, and J. R. Davidson, “A review of magnetic elastomers and their role in soft robotics,” Frontiers in Robotics and AI, Vol.7, Article No.588391, 2020.
  14. [14] U. Gupta, L. Qin, Y. Wang, H. Godaba, and J. Zhu, “Soft robots based on dielectric elastomer actuators: A review,” Smart Materials and Structures, Vol.28, No.10, Article No.103002, 2019.
  15. [15] Y. Zhang, Z. Wang, Y. Yang, Q. Chen, X. Qian, Y. Wu, H. Liang, Y. Xu, Y. Wei, and Y. Ji, “Seamless multimaterial 3D liquid-crystalline elastomer actuators for next-generation entirely soft robots,” Science Advances, Vol.6, No.9, Article No.eaay8606, 2020.
  16. [16] Y. Chen, H. Zhao, J. Mao, P. Chirarattananon, E. F. Helbling, N.-s. P. Hyun, D. R. Clarke, and R. J. Wood, “Controlled flight of a microrobot powered by soft artificial muscles,” Nature, Vol.575, No.7782, pp. 324-329, 2019.
  17. [17] M. Camacho-Lopez, H. Finkelmann, P. Palffy-Muhoray, and M. Shelley, “Fast liquid-crystal elastomer swims into the dark,” Nature Materials, Vol.3, No.5, pp. 307-310, 2004.
  18. [18] Q. He, Z. Wang, Y. Wang, A. Minori, M. T. Tolley, and S. Cai, “Electrically controlled liquid crystal elastomer–based soft tubular actuator with multimodal actuation,” Science Advances, Vol.5, No.10, Article No.eaax5746, 2019.
  19. [19] M. Warner and E. M. Terentjev, “Liquid crystal elastomers,” Oxford University Press, 2007.
  20. [20] C. Ohm, M. Brehmer, and R. Zentel, “Liquid crystalline elastomers as actuators and sensors,” Advanced Materials, Vol.22, No.31, pp. 3366-3387, 2010.
  21. [21] Y. Wang, J. Liu, and S. Yang, “Multi-functional liquid crystal elastomer composites,” Applied Physics Reviews, Vol.9, No.1, Article No.011301, 2022.
  22. [22] H. Zeng, O. M. Wani, P. Wasylczyk, R. Kaczmarek, and A. Priimagi, “Self-regulating iris based on light-actuated liquid crystal elastomer,” Advanced Materials, Vol.29, No.30, Article No.1701814, 2017.
  23. [23] M. Wang, X.-B. Hu, B. Zuo, S. Huang, X.-M. Chen, and H. Yang, “Liquid crystal elastomer actuator with serpentine locomotion,” Chemical Communications, Vol.56, No.55, pp. 7597-7600, 2020.
  24. [24] Y. Yan, Y. Zhao, Y. Alsaid, B. Yao, Y. Zhang, S. Wu, and X. He, “Artificial Phototropic Systems for Enhanced Light Harvesting Based on a Liquid Crystal Elastomer,” Advanced Intelligent Systems, Vol.3, No.10, Article No.2170070, 2021.
  25. [25] F. Ge, R. Yang, X. Tong, F. Camerel, and Y. Zhao, “A multifunctional dye-doped liquid crystal polymer actuator: Light-guided transportation, turning in locomotion, and autonomous motion,” Angewandte Chemie Int. Edition, Vol.57, No.36, pp. 11758-11763, 2018.
  26. [26] Y. Li, Y. Liu, and D. Luo, “Polarization dependent light-driven liquid crystal elastomer actuators based on photothermal effect,” Advanced Optical Materials, Vol.9, No.5, Article No.2001861, 2020.
  27. [27] Y. Geng, R. Kizhakidathazhath, and J. P. Lagerwall, “Robust cholesteric liquid crystal elastomer fibres for mechanochromic textiles,” Nature Materials, Vol.21, pp. 1441-1447, 2022.
  28. [28] L. Ceamanos, Z. Kahveci, M. López-Valdeolivas, D. Liu, D. J. Broer, and C. Sánchez-Somolinos, “Four-dimensional printed liquid crystalline elastomer actuators with fast photoinduced mechanical response toward light-driven robotic functions,” ACS Applied Materials & Interfaces, Vol.12, No.39, pp. 44195-44204, 2020.
  29. [29] T. A. Kent, M. J. Ford, E. J. Markvicka, and C. Majidi, “Soft actuators using liquid crystal elastomers with encapsulated liquid metal joule heaters,” Multifunctional Materials, Vol.3, No.2, Article No.025003, 2020.
  30. [30] W. Zhang, Y. Nan, Z. Wu, Y. Shen, and D. Luo, “Photothermal-Driven Liquid Crystal Elastomers: Materials, Alignment and Applications,” Molecules, Vol.27, No.14, Article No.4330, 2022.
  31. [31] M. Hussain, E. I. L. Jull, R. J. Mandle, T. Raistrick, P. J. Hine, and H. F. Gleeson, “Liquid crystal elastomers for biological applications,” Nanomaterials, Vol.11, No.3, Article No.813, 2021.
  32. [32] S. Krause, F. Zander, G. Bergmann, H. Brandt, H. Wertmer, and H. Finkelmann, “Nematic main-chain elastomers: Coupling and orientational behavior,” Comptes Rendus Chimie, Vol.12, Nos.1-2, pp. 85-104, 2009.
  33. [33] H. Liu, H. Tian, X. Li, X. Chen, K. Zhang, H. Shi, C. Wang, and J. Shao, “Shape-programmable, deformation-locking, and self-sensing artificial muscle based on liquid crystal elastomer and low–melting point alloy,” Science Advances, Vol.8, No.20, Article No.eabn5722, 2022.
  34. [34] A. Kotikian, J. M. Morales, A. Lu, J. Mueller, Z. S. Davidson, J. W. Boley, and J. A. Lewis, “Innervated, Self-Sensing Liquid Crystal Elastomer Actuators with Closed Loop Control,” Advanced Materials, Vol.33, No.27, Article No.2101814, 2021.
  35. [35] J. Wu, W. Ye, Y. Wang, and C.-Y. Su, “Modeling of photo-responsive liquid crystal elastomer actuators,” Information Sciences, Vol.560, pp. 441-455, 2021.
  36. [36] J. Naciri, A. Srinivasan, H. Jeon, N. Nikolov, P. Keller, and B. R. Ratna, “Nematic elastomer fiber actuator,” Macromolecules, Vol.36, No.22, pp. 8499-8505, 2003.
  37. [37] A. Konya, V. Gimenez-Pinto, and R. L. Selinger, “Modeling defects, shape evolution, and programmed auto-origami in liquid crystal elastomers,” Frontiers in Materials, Vol.3, Article No.24, 2016.
  38. [38] M. Groß, J. Dietzsch, and F. Concas, “A new mixed finite element formulation for reorientation in liquid crystalline elastomers,” European J. of Mechanics-A/Solids, Vol.97, Article No.104828, 2023.
  39. [39] G. Skacej and C. Zannoni, “Molecular simulations shed light on supersoft elasticity in polydomain liquid crystal elastomers,” Macromolecules, Vol.47, No.24, pp. 8824-8832, 2014.
  40. [40] V. I. Egorov, O. G. Maksimova, M. Okumura, S. Noro, and H. Koibuchi, “Modeling shape and volume transitions in liquid crystal elastomers,” J. of Physics: Conf. Series, Vol.1730, Article No.012038, 2021.
  41. [41] P. Prathumrat, I. Sbarski, E. Hajizadeh, and M. Nikzad, “A comparative study of force fields for predicting shape memory properties of liquid crystalline elastomers using molecular dynamic simulations,” J. of Applied Physics, Vol.129, No.15, Article No.155101, 2021.
  42. [42] H. Kim and J. Choi, “Interfacial and mechanical properties of liquid crystalline elastomer nanocomposites with grafted Au nanoparticles: A molecular dynamics study,” Polymer, Vol.218, Article No.123525, 2021.
  43. [43] M. Soltani, K. Raahemifar, A. Nokhosteen, F. M. Kashkooli, and E. L. Zoudani, “Numerical methods in studies of liquid crystal elastomers,” Polymers, Vol.13, No.10, Article No.1650, 2021.
  44. [44] Y. Jiang, L. Jin, and Y. Huo, “Unusual stress and strain concentration behaviors at the circular hole of a large monodomain liquid crystal elastomer sheet,” J. of the Mechanics and Physics of Solids, Vol.156, Article No.104615, 2021.
  45. [45] L. A. Mihai, D. Mistry, T. Raistrick, H. F. Gleeson, and A. Goriely, “A mathematical model for the auxetic response of liquid crystal elastomers,” Philosophical Trans. of the Royal Society A, Vol.380, No.2234, Article No.20210326, 2022.
  46. [46] W. Zhu, M. Shelley, and P. Palffy-Muhoray, “Modeling and simulation of liquid-crystal elastomers,” Physical Review E, Vol.83, No.5, Article No.051703, 2011.
  47. [47] G. L. Kusters, I. P. Verheul, N. B. Tito, P. v. d. Schoot, and C. Storm, “Dynamical Landau–de Gennes theory for electrically-responsive liquid crystal networks,” Physical Review E, Vol.102, No.4, Article No.042703, 2020.
  48. [48] Y. Zhang, C. Xuan, Y. Jiang, and Y. Huo, “Continuum mechanical modeling of liquid crystal elastomers as dissipative ordered solids,” J. of the Mechanics and Physics of Solids, Vol.126, pp. 285-303, 2019.
  49. [49] Y. Xu and Y. Huo, “Continuum modeling of the nonlinear electro-opto-mechanical coupling and solid Fréedericksz transition in dielectric liquid crystal elastomers,” Int. J. of Solids and Structures, Vols.219-220, pp. 198-212, 2021.
  50. [50] J. Wu, W. Ye, Y. Wang, and C.-Y. Su, “Modeling Based on a Two-Step Parameter Identification Strategy for Liquid Crystal Elastomer Actuator Considering Dynamic Phase Transition Process,” IEEE Trans. on Cybernetics, 2022.
  51. [51] J. Wu, Y. Wang, W. Ye, and C.-Y. Su, “A Hybrid Model for Photo-Responsive Liquid Crystal Elastomer Actuator,” 2022 13th Asian Control Conf. (ASCC), pp. 1090-1094, 2022.
  52. [52] G. Wang and G. Chen, “Identification of piezoelectric hysteresis by a novel Duhem model based neural network,” Sensors and Actuators A: Physical, Vol.264, pp. 282-288, 2017.
  53. [53] P.-B. Nguyen, S.-B. Choi, and B.-K. Song, “A new approach to hysteresis modelling for a piezoelectric actuator using Preisach model and recursive method with an application to open-loop position tracking control,” Sensors and Actuators A: Physical, Vol.270, pp. 136-152, 2018.
  54. [54] A. Dargahi, S. Rakheja, and R. Sedaghati, “Development of a field dependent Prandtl-Ishlinskii model for magnetorheological elastomers,” Materials & Design, Vol.166, Article No.107608, 2019.
  55. [55] M. Rogóż, H. Zeng, C. Xuan, D. S. Wiersma, and P. Wasylczyk, “Light-driven soft robot mimics caterpillar locomotion in natural scale,” Advanced Optical Materials, Vol.4, No.11, pp. 1689-1694, 2016.
  56. [56] X. Lu, H. Zhang, G. Fei, B. Yu, X. Tong, H. Xia, and Y. Zhao, “Liquid-crystalline dynamic networks doped with gold nanorods showing enhanced photocontrol of actuation,” Advanced Materials, Vol.30, No.14, Article No.1706597, 2018.
  57. [57] O. M. Wani, H. Zeng, and A. Priimagi, “A light-driven artificial flytrap,” Nature Communications, Vol.8, No.1, Article No.15546, 2017.
  58. [58] C. Ahn, X. Liang, and S. Cai, “Bioinspired design of light-powered crawling, squeezing, and jumping untethered soft robot,” Advanced Materials Technologies, Vol.4, No.7, Article No.1900185, 2019.
  59. [59] Y. Zhang and P. Yan, “An adaptive integral sliding mode control approach for piezoelectric nano-manipulation with optimal transient performance,” Mechatronics, Vol.52, pp. 119-126, 2018.
  60. [60] M. C. d. Jong, K. C. Kosaraju, and J. M. A. Scherpen, “On control of voltage-actuated piezoelectric beam: A Krasovskii passivity-based approach,” European J. of Control, Vol.69, Article No.100724, 2023.
  61. [61] X. Zhang, Y. Wang, C. Wang, C.-Y. Su, Z. Li, and X. Chen, “Adaptive estimated inverse output-feedback quantized control for piezoelectric positioning stage,” IEEE Trans. on Cybernetics, Vol.49, No.6, pp. 2106-2118, 2018.
  62. [62] K. Kuhnen, “Modelling, identification, and compensation of complex hysteretic and log(t)-type creep nonlinearities,” Control and Intelligent Systems, Vol.33, No.2, pp. 134-147, 2005.
  63. [63] Z. Li, C.-Y. Su, and T. Chai, “Compensation of hysteresis nonlinearity in magnetostrictive actuators with inverse multiplicative structure for Preisach model,” IEEE Trans. on Automation Science and Engineering, Vol.11, No.2, pp. 613-619, 2013.
  64. [64] Z. Li, J. Shan, and U. Gabbert, “A direct inverse model for hysteresis compensation,” IEEE Trans. on Industrial Electronics, Vol.68, No.5, pp. 4173-4181, 2021.
  65. [65] P. Huang, J. Wu, P. Zhang, Y. Wang, and C.-Y. Su, “Dynamic modeling and tracking control for dielectric elastomer actuator with a model predictive controller,” IEEE Trans. on Industrial Electronics, Vol.69, No.2, pp. 1819-1828, 2022.
  66. [66] G. Yan, “Inverse neural networks modelling of a piezoelectric stage with dominant variable,” J. of the Brazilian Society of Mechanical Sciences and Engineering, Vol.43, No.8, Article No.387, 2021.
  67. [67] J. Wu, Y. Wang, W. Ye, and C.-Y. Su, “Positioning control of liquid crystal elastomer actuator based on double closed-loop system structure,” Control Engineering Practice, Vol.123, Article No.105136, 2022.

*This site is desgined based on HTML5 and CSS3 for modern browsers, e.g. Chrome, Firefox, Safari, Edge, Opera.

Last updated on Jun. 05, 2023