介电型电活性聚合物圆柱形驱动器结构参数分析

介电型电活性聚合物圆柱形驱动器结构简单,能输出较大的位移和力,对其结构参数进行分析是优化设计及合理使用驱动器的基础。通过建立圆柱形驱动器的几何模型分析了驱动器轴向伸长及径厚比对各层膜厚度变化的影响;基于圆柱形驱动器失效模式分析,揭示了结构参数(驱动器膜的预拉伸、卷绕层数、弹簧参数等)对驱动器输出性能的影响。结果表明,驱动器伸长时,小径厚比及较多驱动器膜卷绕层数会使各层膜厚度变化差异显著;基于圆柱形驱动器结构特点,驱动器膜的电击穿、弹簧驱动"失力"及其最大压缩极限变形等失效模式是影响其许用工作范围的主要因素;增加驱动器膜的预拉伸且使其周向延伸率略大于轴向,可获得较佳的综合输出性能;由于层间压力的影响,单独、过多地增加层数对输出性能的提高效果不明显;减小弹簧刚度与长度均能提高驱动器轴向伸长率,但其轴向输出位移量却产生不同变化,同时要注意避免驱动器计算力差超过弹簧预压缩力的情况。

Analysis of Structure Parameters of Dielectric Electroactive Polymer Cylindrical Actuators

Dielectric electroactive polymer (DEAP) cylindrical actuators have a simple structure and strong capability to output large displacements and forces. Analysis of its structural parameters forms the basis for its design optimization and proper operation of DEAP actuators. Through geometric modeling of the actuator, the impact of axial elongation and diameter-thickness ratio on the deformation of each layer was analyzed. Based on the failure mode analysis, the influence of actuator structure parameters of pre-stretch, winding number of the DEAP film, spring parameters, etc. on its performance was obtained. Results showed that small diameter-thickness ratio and large winding layers would change the film thickness difference significantly in each layer when the actuator was elongated. According to the structural features of cylindrical actuators, the main factors affecting the allowable scope of work were the failure modes of electric breakdown of DEAP film, the loss of actuating force of the compression spring, and extreme deformations. The actuators performed better when the pre-stretch was increased and the pre-stretch ratio in circumference was larger than that in axial. No significant effect was observed on the output performance by increasing the layer-number. Reducing the stiffness and length of the spring can increase the axial stretch ratio of the actuator, and it had variable impact on the axial displacement changes. Meanwhile, the calculated force difference should be prevented from exceeding the preloaded force of the spring.