*Article* **Low-Power Embedded System for Gait Classification Using Neural Networks**

## **Francisco Luna-Perejón \*, Manuel Domínguez-Morales, Daniel Gutiérrez-Galán and Antón Civit-Balcells**

Architecture and Computer Technology Department, Universidad de Sevilla, E.T.S Ingeniería Informática, Reina Mercedes Avenue, 41012 Seville, Spain; mjdominguez@us.es (M.D.-M.); dgutierrez5@us.es (D.G.-G.); civit@us.es (A.C.-B.)

**\*** Correspondence: fralunper@atc.us.es

Received: 19 March 2020; Accepted: 17 April 2020; Published: 1 May 2020

**Abstract:** Abnormal foot postures can be measured during the march by plantar pressures in both dynamic and static conditions. These detections may prevent possible injuries to the lower limbs like fractures, ankle sprain or plantar fasciitis. This information can be obtained by an embedded instrumented insole with pressure sensors and a low-power microcontroller. However, these sensors are placed in sparse locations inside the insole, so it is not easy to correlate manually its values with the gait type; that is why a machine learning system is needed. In this work, we analyse the feasibility of integrating a machine learning classifier inside a low-power embedded system in order to obtain information from the user's gait in real-time and prevent future injuries. Moreover, we analyse the execution times, the power consumption and the model effectiveness. The machine learning classifier is trained using an acquired dataset of 3000+ steps from 6 different users. Results prove that this system provides an accuracy over 99% and the power consumption tests obtains a battery autonomy over 25 days.

**Keywords:** machine learning; neural networks; gait analysis; embedded system
