基于介电弹性体和形状记忆聚合物的多稳态抓取结构研究

Investigation of multi-stable grasping structure based on dielectric elastomer and shape memory polymer

介电弹性体是一种典型的智能软材料,具有高的介电常数,且具有重量轻、韧性好、形变大、高弹性能密度以及机电效率高等诸多优点。由介电弹性体制作而成的智能驱动器是通过具有柔性电极的弹性体在电场作用下产生的应变响应进行驱动变形的,在软体机器人、航空航天等许多方面展现出潜在的应用价值。然而,利用介电弹性体制备的抓取结构驱动力较小,将介电弹性体和形状记忆聚合物的变刚度特性相结合,可增加抓取结构的驱动力,并且在抓取和释放过程中无需持续通电即可固定形状。利用介电弹性体的电致变形特性和形状记忆聚合物的形状记忆及变刚度特性,设计了一种智能多稳态抓取结构。建立了驱动器的理论模型,确定结构参数,基于有限元软件对驱动结构的弯曲和恢复过程进行数值模拟,并对其进行弯曲和恢复试验,测试出恢复角度,基于理论和仿真对驱动器结构进行优化设计,基于优化后的驱动器制备了多稳态抓取结构,测试了抓取结构的性能。

Dielectric elastomer is a typical smart soft material with many advantages such as high dielectric constant,light weight,good toughness,large deformation,high elastic energy density,and high electromechanical efficiency.Dielectric elastomer actuator is composed of elastomers and compliant electrodes coated on both surfaces.It can be deformed under the action of voltage,and exhibit potential applications in many aspects such as soft robots and aerospace.However,the force of the grasping structure driven by the dielectric elastomer actuator is relatively small.The combination of dielectric elastomer actuator and shape memory polymer can increase the force of the grasping structure and maintain the grasped or released state without continuous application of voltage.In this work,we proposed a smart multi-stable grasping structure based on the electro-deformation characteristics of dielectric elastomers and the shape memory and variable stiffness characteristics of shape memory polymers.The geometric parameters of the actuator are determined through the established theoretical model,and the bending and recovery process of the grasping structure is analyzed based on the finite element method.The bending and recovery angles of the actuator are tested experimentally.The structure of the actuator is also optimized based on the theoretical model and finite element method.Finally,the multi-stable grasping structure is assembled using the actuator,and its performance is tested experimentally.