# Analyzing and Assisting Finger Motions for Spoon Scooping

## TL;DR

This study develops a soft actuator system to help people with weak hands use a spoon by leveraging their remaining finger motion abilities.

## Contribution

The study introduces a method to assist spoon plunging and lifting using soft actuators based on measured finger motions.

## Key findings

- Finger motions for spoon plunging and lifting were identified using inertial measurement units.
- A dummy hand with soft actuators successfully replicated the identified motions.
- Regulating the moment applied to the spoon enabled effective scooping movements.

## Abstract

Assisting patients with weakened hand and wrist strength during meals is essential. While various feeding devices have been developed, many do not utilize patients’ residual finger functions, leading to an increase in the risk of disuse syndrome and loss of joy in life. Recently, assist-as-needed support for spoon grasping by soft hand rehabilitation devices has been studied. Moreover, in our previous study, we investigated finger motions for the required scooping angle and verified them with a dummy hand driven by soft actuators. However, eating with a spoon requires not only spoon grasping and rotating but also plunging the spoon into food and lifting it afterward. The goal of this study is to achieve self-feeding with spoons using soft actuators for individuals with partial finger disabilities. To address this, we measured scooping movements using inertial measurement units, identified feasible finger motions for spoon plunging and lifting, and verified our findings through experiments with a dummy hand driven by soft actuators. As a result, we found a way to achieve the two motions by regulating the moment applied to the spoon. These results highlight the potential of soft actuators for assisting scooping movements. This study marks an important step toward feeding assistance that leverages patients’ residual finger functions.