Fully 3D Printed Monolithic Soft Gripper with High Conformal Grasping Capability

Abstract

The recent advances in material science and engineering disciplines have had a significant impact on the robotics field where numerous bioinspired soft robots have been developed. Roboticists can now develop and fabricate soft robotic systems made of materials with low elasticity using additive manufacturing technologies. One of the most studied classes of soft robotic systems is soft adaptive grippers. In this work, we present a novel fully 3D printed soft pneumatic gripper that incorporates a novel design of soft pneumatic chambers and a bioinspired fin-ray structure for conformal grasping. The soft gripper was printed in a single step using a low-cost and open-source fused deposition modeling (FDM) 3D printer and a commercially available thermoplastic poly(urethane) (TPU). A soft pneumatic actuator representing each finger of the gripper was optimized using finite element modeling (FEM). The FEM simulations predicted accurately the performance of the actuator in terms of deformation and blocked force. The high conformability of the proposed soft gripper was validated experimentally. The soft gripper was demonstrated lifting a heavy load and grasping a wide variety of objects with different weights, shapes, textures and stiffnesses.

Actuation Technologies for Soft Robot Grippers and Manipulators: A Review

“…The opening and closing of gripper depended on the inflation and deflation of air inside the pneumatic cylinder [14]. Tawk et al enhanced the capabilities of a pneumatically actuated soft gripper by adding structures inspired by Fin-Ray effect (fish fins bend in S-shape when they are subjected to external loadthis way a wrap is formed around the load/object to be grasped resulting in adaptive grasping) such that objects of different shapes, stiffness, and weight could be efficiently grasped [15].…”

3D/4D-printed bending-type soft pneumatic actuators: fabrication, modelling, and control

“…In another study, the Ninjaflex (NinjaTek, PA), with a shore hardness of 85A was used for developing 3D/4D-printed bellow-type SPA where the effects of number and size of the bellows on the curvature bending under the same input pressure were investigated (Keong and Hua 2018). Recently, a bioinspired fin-ray structure for increasing the conformal grasping of the 3D/4D-printed SPA was developed by using commercially available TPU NinjaFlex (NinjaTek, PA) (Tawk, Gao, et al 2019). The 4D-printed soft gripper showed the enhanced capability of lifting objects with various shapes, stiffness, and textures.…”

“…The first group is made by one, or even grouping of two or three of antagonistic fiber-reinforced chambers that control the bending of the actuators through pressure difference between the chambers also called tubular fiber-reinforced actuators (Connolly, Walsh, and Bertoldi 2017;Zhou, Chen, and Wang 2017). However, the second group is designed based on pressurizing air chambers formed by an asymmetric cross-section, with the inextensible bottom layer and an extensible top layer, which converts the pressure change into bending toward the side with the higher bending stiffness, known as bellow-type SPAs (Tawk, Gao, et al 2019). The pneumatic chambers introduced in these SPAs can protect the walls from excessive deformation and thus induce the development of reliability against failure in higher input pressure.…”

3D Printed Soft Pneumatic Bending Sensing Chambers for Bilateral and Remote Control of Soft Robotic Systems

“…A commercial slicer (Simplify3D Inc.) was used to slice the CAD models of the bending chambers. The printing parameters were adjusted and optimized in the slicer based on recent studies [32][33][34][35][36][37][38] to 3D print airtight soft pneumatic bending sensing chambers. The optimized printing parameters are listed in Table I.…”