Soft robotics requires new actuators and artificial muscles that are lighter, less expensive, and more effective than current technologies. Recently developed bubble artificial muscles (BAMs) are lightweight, flexible, inexpensive, pneumatic actuators with the capability of being scalable, contracting at a low pressure, and generating sufficient tension and contraction for assisting human mobility. The BAMs are simply fabricated by using a commercial plastic tubing with retaining rings, forming a “bubble” shape and creating a series of contractile units to attain a desired stroke. They can deliver high contraction through optimization of actuator length and radius, or high tension by strengthening their materials to operate at high pressure. Here, we present a detailed analysis of BAMs, define a model for their actuation, and verify the model through a series of experiments with fabricated BAM actuators. In tests, a maximum contraction of 43.1% and a maximum stress of 0.894 MPa were achieved, corresponding to the BAM lifting a load 1000 times its own weight (5.39 g). The BAM model was built to predict experimental performance, for example, the relationship between tension and contraction at various applied pressures, and between contraction and pressure. Characteristic analysis and design optimization of the BAM are presented as an approach to design and manufacture the ideal “bubble” actuator at any required dimensions. A BAM orthosis is demonstrated as assisting a sit-to-stand transition on a leg mechanism, constructed to match the scale of a human's lower limb. Guidelines for further improvement of the BAM are also included.

中文翻译：

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气泡人工肌肉的特性分析及设计优化

软机器人技术需要新的执行器和人造肌肉，它们比现有技术更轻、更便宜、更有效。最近开发的气泡人工肌肉（BAM）是一种轻质、灵活、廉价的气动执行器，具有可扩展性、低压收缩能力，并能产生足够的张力和收缩以辅助人体活动。BAM 是通过使用带有固定环的商用塑料管来简单制造的，形成“气泡”形状并创建一系列收缩单元以获得所需的行程。它们可以通过优化致动器长度和半径来提供高收缩，或者通过强化其材料以在高压下运行来提供高张力。在这里，我们对 BAM 进行了详细分析，定义了其驱动模型，并通过使用制造的 BAM 驱动器进行的一系列实验验证了该模型。在测试中，实现了 43.1% 的最大收缩和 0.894 MPa 的最大应力，相当于 BAM 提升了 1000 倍自身重量（5.39 g）的负载。BAM 模型旨在预测实验性能，例如各种施加压力下的张力和收缩之间的关系，以及收缩和压力之间的关系。BAM 的特性分析和设计优化是一种设计和制造任何所需尺寸的理想“气泡”执行器的方法。BAM 矫形器被证明可以帮助腿部机构从坐到站的转换，该机构的构造与人类下肢的尺寸相匹配。还包括进一步改进 BAM 的指南。