• 2026-05-08
• O. Olukayode, M.A. Akinro, B.S. Adeboye
• Volume 2, Issue 1

Abstract

Anthropometric grippers are a common form of end-effectors for robotic manipulators. In these grippers, finger flexion and extension are accomplished through linkages and gears (in rigid grippers), tendons (in soft-rigid or flexible grippers) or pneumatically (favoured in soft grippers). In tendon actuation, the fingers are flexed by means of cables in tension and extended by use of elastomers, spring, or another cable at the knuckle. Thus, two separate sets of mechanisms are requred to flex and extend the finger. This increases design complexity. The novelty of this paper is in the simplification of the finger design by using a single flexure strip for both finger extension and flexion. The strip is subjected to a tensile pull during flexion and a compressive push during extension. The strip was routed through the finger with supported and unsupported sections. This enable the strip to withstand reasonable compressive force before buckling. Evaluation tests show that the gripper’s finger developed tip force of 1.1N in flexion and 0.49N in extension. The gripper developed a lifting force of 1.76 N and 1.58 N for the 40 mm and 80 mm test balls used respectively. The gripper’s ability to grasp items of various shapes and sizes was demonstrated. The developed gripper serves as a proof of concept for the feasibility of using a single flexure strip to operate the finger both in flexion and extension.

Download PDF