19 - Compliant Finger Mechanism
Team Members:
Mark Helwig, Evan Kuo, Faith Lee, Matthew Na
Background:
Robotic hand design has advanced significantly, especially in prosthetics and assistive robotics. However, many systems still face a key tradeoff: simple grippers are reliable but struggle with varied object shapes, while highly articulated hands offer dexterity at the cost of increased controller complexity and actuator count.
This brings us to the following Problem Statement:
How can we achieve adaptive, compliant, and human-like grasping using a mechanical system with minimal actuation?
To address this, we developed an under-actuated finger mechanism that transitions between two four-bar linkages using a torsional spring. This allows the finger to change its motion behavior upon contact with an object, enabling sequential bending of its segments with a single actuator. The result is a compliant mechanism that naturally conforms to objects of different shapes and sizes.
The final prototype was refined through iterative CAD and physical testing, improving motion profiles and reducing issues such as excessive distal bending.
The video demonstration below highlights this compliant behavior in action:
Using the first test object, it shows how each finger initially moves as a single unit to grasp it. Next, to grasp the tennis ball, it transitions to a secondary motion mode upon initial contact, allowing the fingers to wrap around it. This demonstrates adaptive grasping on varied sized objects using an under-actuated design.
More information about our project can be found in the following pages:
Table of Contents: