A Novel Sensorised Insole for Sensing Feet Pressure Distributions

TL;DR

This paper introduces a cost-effective, sensorised insole with high spatial resolution capacitive sensors for detailed foot pressure mapping, calibrated with force/torque data, offering an alternative to traditional sensors.

Contribution

The paper presents a novel, low-cost sensorised insole with high spatial resolution and a calibration method that accurately reconstructs contact forces and moments.

Findings

Achieved RMSE of 7 N for contact forces

Achieved RMSE of 2 N m for contact moments

Validated as a cost-effective alternative to force/torque sensors

Abstract

Wearable sensors are gaining in popularity because they enable outdoor experimental monitoring. This paper presents a cost-effective sensorised insole based on a mesh of tactile capacitive sensors. Each sensor's spatial resolution is about 4 taxels/cm^2 in order to have an accurate reconstruction of the contact pressure distribution. As a consequence, the insole provides information such as contact forces, moments, and center of pressure. To retrieve this information, a calibration technique that fuses measurements from a vacuum chamber and shoes equipped with force/torque sensors is proposed. The validation analysis shows that the best performance achieved a root mean square error (RMSE) of about 7 N for the contact forces and 2 N m for the contact moments when using the force/torque shoe data as ground truth. Thus, the insole may be an alternative to force/torque sensors for certain applications, with a considerably more cost-effective and less invasive hardware.