Electromechanically coupled beam models for stacked dielectric elastomer actuators

• Applicant: Professorin Dr.-Ing. Sigrid Leyendecker
• Subject Area: Mechanics
• Term: from 2019 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 426808054

• Final Report Year: 2023

Final Report Abstract

Modern robotic systems still face notable limitations in terms of energy and resource efficiency. Due to the high weight of electrical drives and portable batteries, they are far from being autarkic over a prolonged period of time. Furthermore, the rigid coupling between electrical drives and joints does not allow for smoother motions like they occur in nature, where flexible muscles act as an energy buffer. Due to their potential capability of solving some of the addressed problems, dielectric elastomer actuators (DEAs) are the subject of intense research. Various types of computational models to simulate DEAs are existing with different levels of accuracy and computational efficiency. The gold standard, 3D electromechanically coupled finite element models, are accurate but inherit the drawback of high computational costs. Modelling stacked DEAs (long and thin structures) as an electromechanically coupled beam provides a promising trade-off between accuracy and computational cost. In this project, an electromechanically coupled viscoelastic beam model has been developed. The balance equations for the beam were consistently derived from continuum mechanics via the Lagrange –d’Alembert principle. The simulation results showed that the static and dynamic deformation of the beam model agreed well with the 3D FEM model for different deformation states including, contraction, shear, bending and torsion, however less degrees of freedom were required in the beam model and thus being computationally more efficient. Moreover, the variational time integration ensured a good long term energy behaviour. Subsequently, the developed beam model was integrated as an actuator into multibody systems consisting of rigid and flexible components. The model also represents contact interaction via unilateral constraints between the beam actuator and e.g. a rigid body during the grasping process of a soft robot. The effectiveness of the developed model was demonstrated by various numerical examples, including a cantilever beam, a soft robotic worm and a soft robotic grasper.

Publications

• An electromechanically coupled beam model for dielectric elastomer actuators. Computational Mechanics, 69(3), 805-824.
  Huang, Dengpeng & Leyendecker, Sigrid
  
• Dielectric Elastomer Actuated Multibody System Dynamics and Optimal Control In: 92nd GAMM Annual Meeting (2021), Aachen, 2022-08-15 - 2022-08-19
  Dengpeng Huang & Sigrid Leyendecker
  
• Modelling of dielectric elastomer actuated flexible multibody dynamics In: ECCOMAS Thematic Conference on Multibody Dynamics (2021), Budapest, 2021-12-12 - 2021-12-15
  Dengpeng Huang & Sigrid Leyendecker
  
• Modelling of Electromechanical Coupling in Geometrically Exact Beam Dynamics. 14th WCCM-ECCOMAS Congress. CIMNE.
  Huang, D. & Leyendecker, S.
  
• On computational aspects of electromechanical coupling in geometrically exact beam dynamics In: Online symposium on flexible multibody system dynamics (2021), Zoom, 2020-09-21 - 2020- 09-21
  Dengpeng Huang & Sigrid Leyendecker
  
• Optimal Control of Dielectric Elastomer Actuated Multibody Dynamical Systems. Soft Robotics, 10(5), 897-911.
  Huang, Dengpeng & Leyendecker, Sigrid