Versatile 3D-printed fin-ray effect soft robotic fingers: lightweight optimization and performance analysis

Abstract

Fin ray soft robotic fingers are inspired by the structure and movement of fish fins, enabling flexible and adaptive grasping capabilities. Addressing the challenges of resource efficiency in terms of reduced energy consumption and material expense, this work focuses on further optimizing inherently low-energy fin-ray fingers towards lightweight design. Soft grippers are used frequently in dynamically changing environments and have become inevitable in handling tasks for delicate objects. However, these grippers generally show limited performance and payload-carrying capacity in high-force application scenarios. To address these limitations, topology optimization technique is used here to obtain both gripping capabilities and high factor of safety (FOS) of fingers. The performance of various structures of fin-ray and optimized fingers are analyzed: rectangular, trapezoidal, straight struts, and inclined struts for angles + 45°, − 45°. The topologically optimized structure has 15.2% less mass compared to considered fin-ray finger’s average mass. The deflection coefficient (Cd) is calculated to select the best structure of the fingers based on grasping scenario, and its value should be minimum. The straight strut finger with thickness of t = 2 mm shows best wrapping capabilities compared to all fingers with Cd = 0.1574. The topologically optimized finger’ Cd = 0.1896 at volume fraction of 0.1. Even though the Cd is slightly higher, its FOS is 1.71 times higher. An experimental setup is developed to validate the simulation results with the help of a UR3e robotic arm and an AXIA80 force sensor. The grasping demonstration of soft robotic gripper is performed on various objects: coffee cup and wooden block.