Characterization of Fatigue Behavior of 3D Printed Pneumatic Fluidic Elastomer Actuators

AbstractSoft robots have gained significant interest over the past two decades due to their high flexibility and adaptability to various working conditions. Recent advances in engineering and innovative materials have enabled the design and production of sophisticated soft robotic systems with enhanced capabilities. Additive manufacturing has accelerated the development of soft actuators, unlocking complex kinematics, improving their effectiveness and allowing the production of task-specific actuators. 3D printed soft actuators can gain advantage of the fabricability of complex geometries to guarantee improved mobility and grasping abilities. However, challenges remain in investigating the durability of such devices. Limits of most recent advanced manufacturing methods and materials, with this respect, are still to be fully explored.In this work, bellow-type pneumatic soft actuators fabricated through Fused Filament Fabrication in thermoplastic polyurethane (TPU) are tested to evaluate their fatigue behaviour. Silicone rubber casted actuators are included to provide a point of reference. The actuators integrated resistive flex sensors to monitor bending motion. Fatigue tests were performed with cycles of inflation and deflation until failure. Results showed that 3D printed TPU actuators are capable of whitstanding a significant amount of cycles before failure, ultimately being comparable with alternative fabrication technologies. Overall, this study proves the potential of the Fused Filament Fabrication process for the fabrication of durable, long-lasting pneumatic soft actuators.