基於Yoshimura結構的摺紙式軟性氣動致動器之模組化設計

Abstract

摺紙圖案因高度的可壓縮與可彎曲等特性，近年被廣泛的應用於軟性氣動式致動器(Soft Pneumatic Actuator, SPA)。其中，Yoshimura圖案為基礎的柱狀SPA具有側向彎曲與軸向伸縮的特性。在先前研究中， Yoshimura圖案 SPA有兩種常見的彎曲致動方法。一種為透過預先限制摺紙圖案的摺痕以決定其彎曲模式，另一種則是透過線控的方式使致動器整體彎曲。而這兩種方法都使得致動器的工作空間受到限制。對此，本研究旨在對以Yoshimura摺紙圖案為基礎的SPA進行模組化的設計，透過將致動器模塊化後組合成致動平台，並藉由氣壓的改變控制每個模塊的行程以改變致動平台的彎曲。單一模塊的骨架是將收摺狀態下的Yoshimura圖案進行裁切，並使用軟性膠合材料連接以完成模塊氣室的製作，單層致動平台則是由四個模塊組成。為探討單一模塊與單層致動平台的特徵，單一模塊進行了測量模塊的最大高度與不同氣壓下可施加的力等試驗，單層致動平台則進行載重能力與工作空間的試驗。實驗結果顯示，單個模塊在97.06 kPa氣壓下的最大致動高度為31.325 mm。單層致動器最高可產生100.20 N的力，最大彎曲角度為7.97度，最大伸縮量為14.79 mm。此研究結果可使用於模組堆疊時局部彎曲的控制，並可藉由優化模塊形狀與不同結構組裝以實現平台多方向運動。

In recent years, origami patterns have been widely implemented in soft pneumatic actuators (SPA) because the foldable characteristic allows the actuator to be highly compressible and bendable. Previous studies have found that origami SPA with the Yoshimura pattern can perform lateral bending and axial expansion. These researches have indicated two common methods to control the bending motion of Yoshimura-based SPA. One is to pre-limit the elongation of their pleats to determine its bending mode. The other is to bend the entire actuator by wire-driven actuation. Both methods limit the workspace of the actuator. Therefore, our aim is to modularize the design of the Yoshimura-based SPA. This method will allow the actuator to partially bending in an active actuation. In this study, we have designed a single SPA module based on the Yoshimura pattern, using commercial materials to fabricate the prototype, and utilized 3D printing technology to construct the framework for the combination of multiple modules.In terms of testing, we have conducted preliminary experiments on a single module as well as performance experiments on a single-layer actuator composed of 4 modules. The preliminary experiments included measuring its maximum height, force exerted at various air pressures. The results showed that an individual SPA module has a maximum actuation height of 31.325 mm under the air pressure of 97.06 kPa. The relationship between the force and height under different air pressures was also characterized. Meanwhile, Performance experiments for the single-layer actuator included measuring load capacity and workspace. Results indicated that the single-layer actuator could generate a maximum force of 100.20 N, a maximum bending angle of 7.41 degrees, and a maximum extension of 15.39 mm. These findings can help us to understand the potential performance when stacking the modules together. In the future, we will optimize the module and assemble the modules into various structures.