With intrinsic compliance, soft pneumatic actuators are widely utilized in delicate tasks. However, complex fabrication approaches and limited tunability are still problems. Here, we propose a tunable folding assembly strategy to design and fabricate soft pneumatic actuators called FASPAs (folding assembly soft pneumatic actuators). A FASPA consists only of a folded silicone tube constrained by rubber bands. By designing local stiffness and folding manner, the FASPA can be designed to achieve four configurations, pure bending, discontinuous-curvature bending, helix, and discontinuous-curvature helix. Analytical models are developed to predict the deformation and the tip trajectory of different configurations. Meanwhile, experiments are performed to verify the models. The stiffness, load capacity, output force, and step response are measured, and fatigue tests are performed. Further, grippers with single, double, and triple fingers are assembled by utilizing different types of FASPAs. As such, objects with different shapes, sizes, and weights can be easily grasped. The folding assembly strategy is a promising method to design and fabricate soft robots with complex configurations to complete tough tasks in harsh environments.

中文翻译：

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软气动执行器的可调折叠组装策略。

凭借内在的顺应性，软气动执行器被广泛应用于复杂的任务中。然而，复杂的制造方法和有限的可调性仍然是问题。在这里，我们提出了一种可调折叠组装策略来设计和制造称为 FASPA（折叠组装软气动执行器）的软气动执行器。FASPA 仅由一根用橡皮筋约束的折叠硅胶管组成。通过设计局部刚度和折叠方式，FASPA可以设计成四种构型：纯弯曲、不连续曲率弯曲、螺旋和不连续曲率螺旋。开发分析模型来预测不同配置的变形和尖端轨迹。同时，进行实验验证模型。测量刚度、负载能力、输出力和阶跃响应，并进行疲劳试验。此外，利用不同类型的 FASPA 组装单指、双指和三指的夹具。因此，可以轻松抓取不同形状、大小和重量的物体。折叠组装策略是设计和制造具有复杂配置的软机器人的一种很有前景的方法，可以在恶劣的环境中完成艰巨的任务。