Toward Semi-Autonomous Stiffness Adaptation of Pneumatic Soft Robots: Modeling and Validation

Abstract

The constant stiffness of the soft medical robots imposes a cap on their force transmission capacity. To address this limitation, the objective of this study was to investigate the effects of chamber pressure on the stiffness of pneumatic soft robots. To this end, a single-chamber pneumatic soft robot was designed and fabricated. Afterward, a mechanistic model of the robot under external force and chamber pressure was developed. The model was solved as an initial value problem with homogeneous Neumann and Dirichlet boundary conditions. Comparison of the theoretical findings with experimental results for tip displacement and stiffness showed similar trends with a maximum error of 8.7%. The findings confirmed the feasibility of stiffness adaptation through chamber pressure regulation.