Design of a Breakaway Utensil Attachment for Enhanced Safety in Robot-Assisted Feeding

TL;DR

This paper introduces a mechanically fail-safe breakaway utensil attachment for robot-assisted feeding, enhancing safety by decoupling forces during excessive load, validated through simulations and experiments.

Contribution

The study presents a novel mechanical breakaway design for robot-assisted feeding utensils, with validated FEA and experimental testing, allowing customizable safety thresholds.

Findings

Consistent failure at 1 mm slot depth and 3 wall loops at 65 N force

FEA simulations accurately predicted failure points

Design parameters can be tailored for individual user safety

Abstract

Robot-assisted feeding systems enhance the independence of individuals with motor impairments and alleviate caregiver burden. While existing systems predominantly rely on software-based safety features to mitigate risks during unforeseen collisions, this study explores the use of a mechanical fail-safe to improve safety. We designed a breakaway utensil attachment that decouples forces exerted by the robot on the user when excessive forces occur. Finite element analysis (FEA) simulations were performed to predict failure points under various loading conditions, followed by experimental validation using 3D-printed attachments with variations in slot depth and wall loops. To facilitate testing, a drop test rig was developed and validated. Our results demonstrated a consistent failure point at the slot of the attachment, with a slot depth of 1 mm and three wall loops achieving failure at the target force of 65 N. Additionally, the parameters can be tailored to customize the breakaway force based on user-specific factors, such as comfort and pain tolerance. CAD files and utensil assembly instructions can be found here: https://tinyurl.com/rfa-utensil-attachment