Characterization and Modeling of Fabric-based Pneumatic Actuators with Asymmetric Chambers for Soft Gloves

Fabric-based pneumatic actuators (FPAs) with asymmetric chambers offer exceptional lightweight properties and high output force, making them ideal for soft gloves. However, current characterization and modeling methods for FPAs are generally limited, focusing primarily on single flexion chambers with symmetric cross-sections, specific configurations at restricted positions, and using rudimentary equipment with a constraint panel that introduces superimposed forces. To address these limitations, this study employs a multidimensional force sensor and an XY slide platform without a constraint panel to comprehensively characterize FPA output force. In this sense, we develop static joint equilibrium equations with reduced-dimensional forms, enabling rapid numerical solutions. Our proposed methods accommodate: I) FPAs with antagonistically bonded asymmetric chambers for extension and flexion, II) two-dimensional force description, and III) diverse configurations across the working plane. To account for discrepancies between actual and designed unit geometry, we describe the asymmetry of actual unit deformations in FPAs using the stability theory of compression struts and validate the performance of the model. Our approach accurately predicts FPA configurations across the working plane and provides reliable tip-blocked force estimates. This comprehensive methodology demonstrates significant potential for designing and optimizing FPAs, paving the way for advancements in soft robotics and wearable assistive devices.