Instrumented Crutch Tip for Monitoring Force and Crutch Pitch Angle.

Iñigo Sesar,Jon Torres-Unda,Ana Rodriguez-Larrad,Asier Zubizarreta,Itziar Cabanes,Eva Portillo

doi:10.3390/s19132944

Iñigo Sesar, Jon Torres-Unda + Show 4 more

Open Access

https://doi.org/10.3390/s19132944

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Abstract

In rehabilitation procedures related to the lower limbs, gait monitoring is an important source of information for the therapist. However, many of the approaches proposed in the literature require the use of uncomfortable and invasive devices. In this work, an instrumented tip is developed and detailed, which can be connected to any crutch. The instrumented tip provides objective data of the crutch motion, which, combined with patient movement data, might be used to monitor the daily activities or assess the recovery status of the patient. For that purpose, the tip integrates a two-axis inclinometer, a tri-axial gyroscope, and a force sensor to measure the force exerted on the crutch. In addition, a novel algorithm to estimate the pitch angle of the crutch is developed. The proposed approach is tested experimentally, obtaining acceptable accuracies and demonstrating the validity of the proposed lightweight, portable solution for gait monitoring.

Highlights

Gait monitoring and analysis are of high interest, as patients suffering from a lower-limb impairment usually report a decrease in their autonomy and quality of life, and a poorer health status [1,2,3]
The authors in [32] did not disclose the value of the mean root mean squared (RMS) error in the estimation of the crutch inclination during normal walking, they presented a plot comparing the crutch tilt angles measured by an motion capture systems (MCS) and the approach proposed in that article
An instrumented crutch or cane for gait monitoring in rehabilitation can be used to monitor crutch movement variables, which might be related to the recovery status of a patient that requires rehabilitation

Summary

Introduction

Gait monitoring and analysis are of high interest, as patients suffering from a lower-limb impairment usually report a decrease in their autonomy and quality of life, and a poorer health status [1,2,3]. Researchers have shown the benefits of using diagnosis instruments such as miniature sensors and optical systems for monitoring and assessing patient recovery [8,9,10,11]. Instrumented gait monitoring is usually performed using portable pressure-sensitive walkways, motion capture systems (MCS), or wearable sensors [12]. The second approach provides accurate monitoring of all kinds of movements during gait, with instantaneous position errors under 1 mm [11], but their use is limited to indoor scenarios; their cost is high; and they require long set up and post-processing times [14,15]. The attachment of the sensors to the body (including their location and orientation), the vibrations and noise, the drift or accumulated error, the external magnetic perturbations, and the complicated algorithms to estimate the orientation still present significant challenges [15,17,18]

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