Design and evaluation of 3D-printed soft pneumatic actuators

Abstract

Soft robotics enables safe and adaptive manipulation of delicate objects, with pneumatic actuators offering a flexible alternative to rigid systems. This study explores the design, simulation, fabrication, and testing of a pneumatic soft gripper manufactured via Fused Filament Fabrication using thermoplastic polyurethane. The response of four actuator designs, two chamber-based and two channel-based variants, was evaluated. The influence of geometric variations in chamber height, inter-chamber spacing, and number of chambers was analyzed using finite element analysis. The three-parameter Mooney–Rivlin model was used to predict the material’s response across operating pressures. Actuators with rectangular chambers achieved the highest blocking force, whereas the channel-based modification increased flexion for about 20–33% relative to the base design. One actuator from each model was additively manufactured with thermoplastic polyurethane filament to validate the numerical results, with a relative error in the 8-19% range. Finally, a gripper built using one of the designs successfully handled various objects (e.g., tomatoes, bananas) weighing up to 254g, although it struggled with smooth cylindrical items (e.g., spray cans). These findings demonstrate the feasibility of FFF pneumatic actuators and highlight key design trade-offs for soft robotic applications.