基于材料和结构方法的介电弹性体及驱动器性能研究

【作者】 张振；

【导师】 何田；

【作者基本信息】 青岛大学 ， 机械（专业学位）， 2023， 硕士

【摘要】 软体机器人具有密度低、质量轻、材质柔软可变形、工作安静无排放、安全环保又节能等优点,因此在高人机交互场景和非结构化环境中具有广泛应用前景。介电弹性体等智能软材料制作的驱动器组件是软体机器人实现运动和智能交互的核心,其性能决定了机器人整体的功能上限。然而,软材料驱动器的综合性能受材料性能和结构设计的直接影响,由于软体机器人驱动器领域方兴未艾,对其理论、材料和结构设计等方面的研究尚不成熟,需要进一步深入探索其潜力。本文主要通过理论模型分析及有限元模拟方法,通过合成介电弹性体薄膜材料和电极材料,并检测其各项性能,以及对多种简单结构驱动器的结构参数与驱动效果的研究,探索实现驱动性能增强的有效方法,为制造大驱动力、大变形及高变形自由度的驱动器去除阻碍,为进一步的软体机器人结构参数优化等研究奠定基础。采用自由能密度函数表示的不可压缩理想介电弹性体模型,结合多种通过主伸长率及应变不变量表示的超弹性材料模型,建立力电耦合大变形分析的理论框架。讨论了各种非理想条件因素,并总结其函数表示的方案。在此基础上,通过模型的理论推导和计算,分析了不同变形模式下,电致变形过程中,应力-应变与预拉伸状态间的计算公式。分析、计算了在多种失效形式限制下的驱动变形的安全空间。材料性能对介电弹性体及驱动器的驱动性能具有直接影响。对实验室合成的以CN9021NS低聚物作为基体的介电弹性体材料,其力学和介电性能进行测试。和性能增强方法进行了探索。通过实验探索了基于sylgard184材料基体的复合材料聚合物柔性电极的材料配比和制作工艺,对包括单壁碳纳米管、导电碳酯及炭黑等成分的作用进行分析,获得了拉伸性能良好的层状电极。对比测试了多种电极在拉伸变形状态的方阻变化。为后续进一步的制造工艺和材料性能优化研究充实了基础。驱动器的结构直接决定了其变形模式、致动能力和输出力的大小。基于有限元方法,详细介绍了采用abaqus软件和子程序对介电弹性体驱动器的变形进行仿真的分析流程。按照由简及难顺序,依次分析了拮抗机制的平面单层推挽式驱动器、层状弯曲驱动器、卷状多层驱动器及弹簧卷曲驱动器等多种结构。研究了结构尺寸参数对驱动效果的影响,证实检验叠层工艺、拮抗机制和刚柔耦合结构对驱动器变形能力的提升效果,并寻求参数优化设计。更多还原

【Abstract】 Soft robots have attracted extensive attention in high human-robot interaction scenarios and unstructured environments due to their low density,lightweight,flexible and deformable materials,quiet and emission-free operation,as well as safety,environmental friendliness,and energy efficiency.The actuator components made of smart materials such as dielectric elastomers are the core of achieving motion and intelligent interaction in soft robots,and their performance determines the overall functionality of the robots.However,the comprehensive performance of soft material actuators is directly influenced by material properties and structural design.As the field of soft robot actuators is still emerging,research on their theory,materials,and structural design is not yet mature,requiring further exploration of their potential.This paper primarily focuses on the analysis of large deformation coupling between electrical and mechanical effects by employing theoretical modeling and finite element simulation methods.It explores effective approaches to enhance actuator performance by synthesizing dielectric elastomer thin film materials,electrode materials,and evaluating their various properties.The study investigates the structural parameters and driving effects of various simple structural actuators,aiming to remove obstacles for the development of high driving force,large deformation,and high degree of freedom actuators,laying the foundation for further optimization of structural parameters in soft robots.A theoretical framework for analyzing the coupling between electrical and mechanical effects in large deformations is established,utilizing the free energy density function to represent the incompressible ideal dielectric elastomer model and incorporating various hyperelastic material models represented by principal stretch ratios and strain invariants.Various non-ideal factors are discussed,and their functional representations are summarized.Based on this framework,the paper analyzes the calculation formulas for stress-strain and prestretch states during the electro-induced deformation process under different deformation modes.The safe space for driving deformation is analyzed and calculated under various failure mode restrictions.The performance of materials has a direct impact on the driving performance of dielectric elastomers and actuators.Laboratory-synthesized dielectric elastomer materials based on CN9021 NS polymer as the matrix are tested for their mechanical and dielectric properties.The study explores methods to enhance their performance.The material ratio and fabrication process of composite polymer flexible electrodes based on the sylgard184 material matrix are investigated experimentally,analyzing the effects of components such as single-walled carbon nanotubes,conductive carbon esters,and carbon black,and obtaining layered electrodes with excellent stretching performance.Comparative tests are conducted to evaluate the changes in sheet resistance of various electrodes under tensile deformation,enriching the foundation for subsequent research on manufacturing processes and material performance optimization.The structure of the actuator directly determines its deformation mode,actuation capability,and output force.This paper presents a detailed analysis process for simulating the deformation of dielectric elastomer actuators using the Abaqus software and subroutines based on the finite element method.In a progressive manner,the analysis includes various structures such as planar single-layer antagonistic actuators,layered bending actuators,multi-layer roll actuators,and spring-coiled actuators.The influence of structural dimension parameters on the actuation performance is studied.The effectiveness of testing layering techniques,antagonistic mechanisms,and rigid-flex coupling structures in enhancing the actuator’s deformation capabilities is confirmed,and parameter optimization design is sought.更多还原