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

2025-02-25

AI Summary

Robotic feeding systems pose injury risks to users due to unintended collisions, necessitating fail-safe mechanisms that mitigate mechanical overloads. Method: This work introduces a mechanically triggered, fail-safe utensil coupler for assistive feeding robots—first of its kind—designed to decouple autonomously under excessive force. Leveraging finite element analysis (FEA), the coupling geometry is optimized; parametric 3D printing enables precise control of groove depth and annular wall configuration. A dedicated drop-test rig and quasi-static mechanical testing system are developed for empirical validation. Results: A 1-mm groove depth with triple-annulus geometry achieves stable disengagement at the target rupture force of 65 N, with <5% deviation. The rupture threshold is fully adjustable to accommodate individual pain thresholds and comfort requirements. All CAD models and assembly documentation are publicly released under an open-source license.

Technology Category

• Intelligent Robots: Manipulation
• Natural Language Processing: Safety and Robustness
• Philosophy and Ethics of AI: Safety, Robustness & Trustworthiness

Application Category

• Responsible Web: Machine-in-the-loop, human agency and autonomy
• User Modeling, Personalization and Recommendation: Federated recommendation systems and personalization
• Systems and Infrastructure for Web, Mobile and WoT: Decentralized Web and Fediverse systems

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

Problem

• Mechanical fail-safe for robot-assisted feeding
• Breakaway utensil attachment for safety
• Customizable force based on user factors

Innovation

• Mechanical breakaway utensil attachment
• Finite element analysis simulations
• Customizable force parameters