Comparative Evaluation of Gait Event Detection Methods Based on a Single IMU: Error Sensitivity Analysis to IMU Positioning

Abstract

In this study, five different gait event detection methods using a single Inertial Measurement Unit (IMU) were evaluated. Since gait events identification is mostly based on the observation of features characterizing the acceleration patterns, a misalignment of the IMU may cause changes in these. Thus, a correct positioning of the IMU is crucial for the successful application of the abovementioned methods. First, IMU data were acquired and IMU inclination in the sagittal plane estimated at different trunk locations on twelve subject standing upright. Inter-subject variability was evaluated to estimate the range of the IMU inclination. Then, acceleration data for each IMU location were acquired from one subject during a 10 m walk. To simulate accelerometer signals related to different IMU inclinations, the IMU was virtually rotated within the range of the IMU inclination. Initial contact instants were then evaluated applying the five methods and compared with the data acquired by a stereo-photogrammetric system.