Introducing PNEUMA: A Hybrid Soft Pneumatic Fabric Bidirectional Actuation Module for Wearable Robotics

Soft inflatable fabric actuators are lightweight and compliant, but are typically limited to unidirectional force/torque generation and large inflation volumes. This work presents PNEUMA: a soft inflatable fabric bidirectional actuation module capable of generating high torque in both bending directions within a single integrated architecture. The actuator delivers peak torques of 50 Nm at 0.3 MPa, with an inflation volume of ≈100 mL and a mass of 120 g, achieving a high torque‐to‐weight ratio across a motion range of 150°. Experimental characterization confirms consistent static and dynamic performance, as well as robustness under repeated pressurization up to 0.4 MPa. Integration into a knee exosuit demonstrates functional effectiveness. During the sit‐to‐stand task, peak activation of the extensor muscle decreases by 24% without significant kinematic changes. During step descent, flexor muscle activation decreases by up to 33%, indicating substantial biological torque assistance. During an isometric squat task, extensor activation decreased by 35%, accompanied by a reduction in metabolic cost of up to 23% by the end of the experimental set. The proposed architecture overcomes key limitations of conventional soft inflatable fabric actuators and provides an efficient building block for portable wearable and soft robotic systems that require bidirectional, high‐torque control.