Integrated Modelling And Design Optimization Of Planar Dielectric Elastomer Actuators

Compared with conventional rigid robots,soft robots show advantages towards applications in unstructured environments due to their inherent com-pliance.By providing the driving force,soft actuators are the key component of soft robots.Among different types of actuators,dielectric elastomer ac-tuators(DEAs)have attributes of compact structure,large deformation and rapid response.However,the interplay between the geometry,material prop-erties,and external electric fields makes it difficult to accurately model the DEA system,and a theoretical framework is yet to develop for design.To address this problem,the author proposes an integrated modelling method of DEAs,investigates the integrated design of planar dielectric elastomer mini-mum energy structures(DEMES),develops a 3D printing-based compatible fabrication process,and realizes prototypes of actuators and a locomotive robot.The main work and innovations of this thesis are summarized as fol-lows.The existing finite element method based on solid elements usually suf-fers from convergence issues and high computation cost.The author pro-poses using membrane elements to describe dielectric elastomers,and de-velops the material subroutine to be embedded in the finite element software to accurately and efficiently analyze their nonlinear large deformation.An integrated modelling and analysis method of DEMES actuators are further developed by incorporating flexible supporting structures.In view of existing DEMES fabrication methods that mainly rely on manual process accompanied with low efficiency and poor adhesion,this thesis proposes a fabrication strategy which directly constructs the flexible support structure on the dielectric elastomer membrane by a 3D printer with stable bonding between the material interface.Based on the developed finite element analysis tool and fabrication method,a parametric description of the planar DEMES actuators is con-structed and parameter optimization is carried out to explore the deforma-tion of the actuators.The experiment results of optimized design show that the actuation strain reaches 38.6%,which outperforms existing DEMES ac-tuators.The combination of the optimized actuator with electroadhesions creates a planar locomotive robot that can quickly crawl through confined environments.Using the integrated modelling and design method,how the anisotropy of meta-structures programs the deformation of DEAs is investigated.A unidirectional actuator is realized to validate the concept,which represents a conceptual attempt towards novel smart metamaterials based on dielectric elastomers.