Wu Changchun, Liu Hao, Lin Senyuan, Lam James, Xi Ning, Chen Yonghua
Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, Hong Kong.
Department of Data and Systems Engineering, The University of Hong Kong, Hong Kong, Hong Kong.
Nat Commun. 2025 Apr 22;16(1):3787. doi: 10.1038/s41467-025-59051-3.
Shape morphing technologies are significant in soft robotic applications. To this end, we introduce a new shape morphing approach using pneumatic torsion strips, inspired by the shape of a Möbius strip. A pneumatic torsion strip is simply formed by bending and twisting a ribbon of bladder. When locating a pneumatic torsion strip on a braided soft body, its intrinsic elastic energy always tends to bend the soft body. Meanwhile, its elastic energy is adjustable and correlated with the geometry and internal-pressure dependent material properties. Compared with common strain-mismatch based morphing methods, pneumatic torsion strips directly exert bending torque to the soft body without generating in-plane strain and affecting rigidity. As such, the local bending of a soft body over a large curvature range at almost any position can be realized through pneumatic torsion strips. A mathematical model describing the geometry and elastic energy of a pneumatic torsion strip is also established to explain its basic shape morphing mechanism. Finally, we provide several case studies to illustrate their performance and advantages in practical shape morphing applications, such as a 2 kg meter-scale transformable carpet that can curl like plant tendrils.
形状变形技术在软体机器人应用中具有重要意义。为此，我们受莫比乌斯带形状的启发，引入了一种使用气动扭转条的新型形状变形方法。气动扭转条简单地通过弯曲和扭转一条气囊带形成。当将气动扭转条放置在编织软体上时，其固有弹性能量总是倾向于使软体弯曲。同时，其弹性能量是可调节的，并且与几何形状和依赖于内部压力的材料特性相关。与基于常见应变不匹配的变形方法相比，气动扭转条直接对软体施加弯曲扭矩，而不会产生面内应变和影响刚度。因此，通过气动扭转条可以在几乎任何位置实现软体在大曲率范围内的局部弯曲。还建立了一个描述气动扭转条几何形状和弹性能量的数学模型，以解释其基本形状变形机制。最后，我们提供了几个案例研究，以说明它们在实际形状变形应用中的性能和优势，例如一个2千克的米级可变形地毯，它可以像植物卷须一样卷曲。
