Soft continuum arms (SCAs) promise versatile manipulation through mechanical compliance, for assistive devices, agriculture, search applications, or surgery. However, the strong nonlinear coupling between materials, morphology, and actuation renders design and control challenging, hindering real-world deployment. In this context, a modular fabrication strategy paired with reliable, interactive simulations would be highly beneficial, streamlining prototyping and control design. Here, we present a digital twin framework for modular SCAs realized using pneumatic Fiber-Reinforced Elastomeric Enclosures (FREEs). The approach models assemblies of FREE actuators through networks of Cosserat rods, favoring the accurate simulation of three-dimensional arm reconfigurations, while explicitly preserving internal modular architecture. This enables the quantitative analysis and scalable development of composite soft robot arms, overcoming limitations of current monolithic continuum models. To validate the framework, we introduce a three-dimensional reconstruction pipeline tailored to soft, slender, small-volume, and highly deformable structures, allowing reliable recovery of arm kinematics and strain distributions. Experimental results across multiple configurations and actuation regimes demonstrate close agreement with simulations. Finally, we embed the digital twins in a virtual environment to allow interactive control design and sim-to-real deployment, establishing a foundation for principled co-design and remote operation of modular soft continuum manipulators.

翻译：软体连续臂（SCAs）凭借其机械柔顺性，在辅助设备、农业、搜索应用或手术等领域展现出多功能操作的潜力。然而，材料、形态与驱动之间强烈的非线性耦合使得其设计与控制极具挑战性，阻碍了实际应用。在此背景下，模块化制造策略与可靠、交互式仿真相结合将大有裨益，可简化原型设计及控制方案开发。本文提出一种面向模块化SCAs的数字孪生框架，该框架采用气动纤维增强弹性体封装单元（FREEs）实现。该方法通过Cosserat杆网络对FREE执行器组件进行建模，优先保证三维臂形重构的精确仿真，同时显式保留内部模块化架构。这有助于实现复合软体机械臂的定量分析与可扩展开发，克服当前整体连续体模型的局限性。为验证该框架，我们引入一种专为柔软、细长、小体积及高变形结构定制的三维重建流程，能够可靠地复原臂体运动学与应变分布。多种构型与驱动模式下的实验结果均表明与仿真高度吻合。最后，我们将数字孪生嵌入虚拟环境，以实现交互式控制设计与仿真到现实的部署，为模块化软体连续机械臂的协同设计与远程操作奠定理论基础。