A soft wearable sleeve for joint stiffness modulation

In this paper, we present the design and analysis of a soft wearable sleeve capable of modulating the stiffness of a joint. The sleeve uses a novel fabric-like architecture of miniaturized soft fluidic actuators known as Fiber Reinforced Elastomeric Enclosures (FREEs). By selective actuation of FREEs in this architecture, we demonstrate joint stiffening in either one or both directions. The paper presents an analytical formulation to capture this stiffness modulation by (a) predicting stroke and forces generated by individual FREEs, and (b) applying them in the context of the architecture geometry to predict joint stiffness. We further verify the stiffness model with experimental bench top testing. The sleeve is soft, lightweight and discreet - worn under standard clothing - and can be configured for any joint and size.