Textile based pneumatic actuators have recently seen increased development for use in wearable applications thanks to their high strength to weight ratio and range of achievable actuation modalities. However, the design of these textile-based actuators is typically an iterative process due to the complexity of predicting the soft and compliant behavior of the textiles. In this work we investigate the actuation mechanics of a range of physical prototypes of unfolding textile-based actuators to understand and develop an intuition for how the geometric parameters of the actuator affect the moment it generates, enabling more deterministic designs in the future. Under benchtop conditions the actuators were characterized at a range of actuator angles and pressures (0 – 136 kPa), and three distinct performance regimes were observed, which we define as Shearing, Creasing, and Flattening. During Flattening, the effects of both the length and radius of the actuator dominate with maximum moments in excess of 80 Nm being generated, while during Creasing the radius dominates with generated moments scaling with the cube of the radius. Low stiffness spring like behavior is observed in the Shearing regime, which occurs as the actuator approaches its unfolded angle. A piecewise analytical model was also developed and compared to the experimental results within each regime. Finally, a prototype actuator was also integrated into a shoulder assisting wearable robot, and on-body characterization of this robot was performed on five healthy individuals to observe the behavior of the actuators in a wearable application. Results from this characterization highlight that these actuators can generate useful on-body moments (10.74 Nm at 90° actuator angle) but that there are significant reductions compared to bench-top performance, in particular when mostly folded and at higher pressures.

中文翻译：

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展开用于可穿戴应用的基于纺织品的气动执行器

由于其高强度重量比和可实现的致动方式范围，基于纺织品的气动致动器最近在可穿戴应用中得到了越来越多的发展。然而，由于预测纺织品柔软和柔顺行为的复杂性，这些基于纺织品的致动器的设计通常是一个迭代过程。在这项工作中，我们研究了一系列展开基于纺织品的致动器的物理原型的致动机制，以了解和发展对致动器的几何参数如何影响其产生的时刻的直觉，从而在未来实现更多确定性的设计。在台式条件下，执行器在一系列执行器角度和压力（0 – 136 kPa）下进行了表征，并观察到三种不同的性能状态，我们将其定义为剪切、折痕和压平。在展平过程中，执行器的长度和半径的影响主要是产生超过 80 Nm 的最大力矩，而在压痕过程中，半径主要是产生的力矩与半径的立方成比例。在剪切状态下观察到低刚度弹簧状行为，这种行为发生在执行器接近其展开角时。还开发了一个分段分析模型，并与每个方案内的实验结果进行了比较。最后，还将一个原型执行器集成到肩部辅助可穿戴机器人中，并在五个健康人身上对该机器人进行了身体表征，以观察执行器在可穿戴应用中的行为。