Heavy-load lifting through topology-optimized and lightweight bronze chain grippers

Abstract

The increasing complexity of industrial manufacturing and the need for adaptable grasping solutions have driven research towards innovative end-effector designs. This paper presents an evolution of the chain gripper developed by the authors, an adaptive manipulator capable of handling objects of varying shapes without requiring specific tooling. The proposed system is based on a flexi-rigid structure, integrating the advantages of continuum manipulators and deployable mechanisms. A topology optimization process was applied to minimize weight while maintaining structural strength and integrity, leading to a revised geometry manufactured using lost-wax casting in bronze. The optimized prototype was subjected to tensile testing to validate its mechanical performance, demonstrating high load-bearing capacity and excellent damage compliance. Compared to the previous ABS prototype, the optimized design halves the mass of each chain element and decreases the maximum Von Mises stress. Experimental validation confirmed the finite element model predictions, with a limited deviation in stiffness, and was used to quantify the maximum liftable load with a fixed number of chain elements. The results confirm the feasibility of the chain gripper as a cost-effective, lightweight, and easily deployable solution for industrial applications in which flexibility and robustness are required.

Graphical abstract