Highly compliant silicone 3D-printed dual mode soft robotic gripper

Soft robotic grippers are increasingly preferred for object manipulation due to their enhanced-grasping capabilities, safe interaction, and high flexibility. This research presents a modular approach to 3D printing of a soft gripper with three silicone fingers, shape memory alloy springs as actuators, and spring steel elements for returning the fingers to their original position. The novelty lies in the one-shot fabrication of the soft fingers using a custom-made material extrusion machine, eliminating the need for support structures. The 3D printing setup, combined with a cartesian pick and place robot, automates the fabrication process. Two gripper configurations, horizontal and vertical, were achieved by assembling the soft fingers in different holders. The silicone fingers (100 × 8.5 × 30 mm) were used to grasp small medical equipment, showing high flexibility and a bending angle of ~60° at 4 A and 6.5 V, mimicking human finger motion. Finite Element Method analysis was used to study the dynamic behaviour, deformation, and stress of the fingers. The average stiffness and elastic modulus were 276 N/m and 0.014 MPa, respectively. The grippers were attached to a 3D printed child-sized humanoid robot to demonstrate their capabilities, highlighting their potential in medical robotics.