Learning a Shared Model for Motorized Prosthetic Joints to Predict Ankle-Joint Motion

TL;DR

This paper introduces a neural network-based shared model that predicts ankle joint motion across various locomotion modes without explicit mode classification, aiding the development of adaptive prosthetic control systems.

Contribution

The study presents a novel shared predictive model for ankle motion that works across multiple locomotion modes without mode-specific classification.

Findings

Shared model accurately predicts ankle angles and moments across modes

Model reduces need for explicit mode classification in prosthetic control

Potential for high-level adaptive prosthetic ankle controllers

Abstract

Control strategies for active prostheses or orthoses use sensor inputs to recognize the user's locomotive intention and generate corresponding control commands for producing the desired locomotion. In this paper, we propose a learning-based shared model for predicting ankle-joint motion for different locomotion modes like level-ground walking, stair ascent, stair descent, slope ascent, and slope descent without the need to classify between them. Features extracted from hip and knee joint angular motion are used to continuously predict the ankle angles and moments using a Feed-Forward Neural Network-based shared model. We show that the shared model is adequate for predicting the ankle angles and moments for different locomotion modes without explicitly classifying between the modes. The proposed strategy shows the potential for devising a high-level controller for an intelligent prosthetic ankle that can adapt to different locomotion modes.