Soft, growing inflated beam robots, also known as everting vine robots, have previously been shown to navigate confined spaces with ease. Less is known about their ability to navigate three-dimensional open spaces where they have the potential to collapse under their own weight as they attempt to move through a space. Previous work has studied collapse of inflated beams and vine robots due to purely transverse or purely axial external loads. Here, we extend previous models to predict the length at which straight vine robots will collapse under their own weight at arbitrary launch angle relative to gravity, inflated diameter, and internal pressure. Our model successfully predicts the general trends of collapse behavior of straight vine robots. We find that collapse length increases non-linearly with the robot's launch angle magnitude, linearly with the robot's diameter, and with the square root of the robot's internal pressure. We also demonstrate the use of our model to determine the robot parameters required to grow a vine robot across a gap in the floor. This work forms the foundation of an approach for modeling the collapse of vine robots and inflated beams in arbitrary shapes.

翻译：软体充气生长梁式机器人（也称外翻式藤蔓机器人）此前已被证明能轻松穿越受限空间。然而，关于其在三维开放空间中航行时，因试图穿越空间而可能在自重下发生坍塌的能力仍知之甚少。已有工作研究了纯横向或纯轴向外部载荷下充气梁与藤蔓机器人的坍塌现象。本文拓展了现有模型，以预测直状藤蔓机器人在任意发射角度（相对于重力方向）、充气直径和内部压力下发生自重坍塌的长度。我们的模型成功预测了直状藤蔓机器人坍塌行为的一般趋势。研究发现：坍塌长度随机器人发射角度的增大呈非线性增加，随直径的增大呈线性增加，并随内部压力的平方根增大而增加。我们还展示了如何利用该模型确定机器人跨越地面间隙所需的关键参数。本研究为建立任意形状藤蔓机器人与充气梁的坍塌建模方法奠定了理论基础。