A unified framework for soft inflatable fabric actuators

Soft inflatable fabric actuators are gaining traction in soft robotics due to their lightweight, compliant structures and capacity for generating diverse motions. However, the increasing diversity and structural complexity of their designs present significant challenges for scalable modeling and predictive performance analysis. Here, we present a unified taxonomy of soft inflatable fabric actuators, built around a stiffening actuator as a fundamental unit cell. We introduce a spring-based modeling framework that captures the mechanical behavior of complex actuator types- including elongating, contracting, and bending- through modular combinations of individual units in series or parallel. High-fidelity finite element simulations, validated experimentally, show that the mechanical response of complex multi-chamber actuators can be accurately inferred from the behavior of a single unit. Two case studies demonstrate the framework's practical utility for task-specific actuator design, eliminating the need for iterative prototyping or computationally expensive modeling. This scalable and generalizable approach enables efficient soft actuator design for a wide range of applications, including but not limited to wearable systems, robotic manipulation, biomedical devices, and adaptive or morphing structures.