Pneumatic artificial muscles (PAMs) are an extensively investigated type of soft actuator. However, the PAM motions have been limited somewhat to uniaxial contraction and extension, restraining the development of PAMs. Given the current strong interest in soft robotics, PAMs have been gaining renewed attention due to their excellent compliance and ease of fabrication. Herein, under the inspiration of the elephant trunk, a family of bending and helical extensile PAMs (HE-PAMs)/helical contractile PAMs (HC-PAMs) was proposed and analyzed. Through both experiment and analysis, a model of generalized bending behavior of PAMs was built and developed to investigate the properties of axial, bending, and helical PAMs in the same theoretical framework. The topological equivalence and bifurcation were found in the analysis and utilized to explain the behaviors of these different PAMs. Meanwhile, a coupled constant curvature and torsion kinematics model was proposed to depict the motion of PAMs more accurately and conveniently. Moreover, a soft tandem manipulator consisting of bending and helical PAMs was proposed to demonstrate their attractive potential.

中文翻译：

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以象鼻为灵感的新型弯曲和螺旋伸展/收缩气动人造肌肉

气动人工肌肉 (PAM) 是一种经过广泛研究的软致动​​器。然而，PAM 运动在一定程度上仅限于单轴收缩和伸展，从而限制了 PAM 的发展。鉴于当前对软机器人的浓厚兴趣，PAM 因其出色的合规性和易于制造而重新获得关注。在此, 在象鼻的启发下, 提出并分析了一个弯曲和螺旋伸展 PAM (HE-PAM)/螺旋收缩 PAM (HC-PAM) 家族。通过实验和分析，建立和开发了 PAM 的广义弯曲行为模型，以在同一理论框架下研究轴向、弯曲和螺旋 PAM 的特性。在分析中发现了拓扑等价和分岔，并用于解释这些不同 PAM 的行为。同时，为了更准确、更方便地描述PAMs的运动，提出了一种耦合的恒定曲率和扭转运动学模型。此外，提出了一种由弯曲和螺旋 PAM 组成的软串联机械手，以展示其吸引人的潜力。