Frank J Wouda1, Stephan L J O Jaspar2, Jaap Harlaar3,4, Bert-Jan F van Beijnum2, Peter H Veltink2. 1. Faculty of Electrical Engineering, Mathematics and Computer Science, University of Twente, Enschede, The Netherlands. frankwouda@gmail.com. 2. Faculty of Electrical Engineering, Mathematics and Computer Science, University of Twente, Enschede, The Netherlands. 3. Department of Rehabilitation Medicine, Amsterdam Movement Sciences, VU University Medical Center, Amsterdam, The Netherlands. 4. Department of Biomechanical Engineering, Delft University of Technology, Delft, The Netherlands.
Abstract
BACKGROUND: The foot progression angle is an important measure used to help patients reduce their knee adduction moment. Current measurement systems are either lab-bounded or do not function in all environments (e.g., magnetically distorted). This work proposes a novel approach to estimate foot progression angle using a single foot-worn inertial sensor (accelerometer and gyroscope). METHODS: The approach uses a dynamic step frame that is recalculated for the stance phase of each step to calculate the foot trajectory relative to that frame, to minimize effects of drift and to eliminate the need for a magnetometer. The foot progression angle (FPA) is then calculated as the angle between walking direction and the dynamic step frame. This approach was validated by gait measurements with five subjects walking with three gait types (normal, toe-in and toe-out). RESULTS: The FPA was estimated with a maximum mean error of ~ 2.6° over all gait conditions. Additionally, the proposed inertial approach can significantly differentiate between the three different gait types. CONCLUSION: The proposed approach can effectively estimate differences in FPA without requiring a heading reference (magnetometer). This work enables feedback applications on FPA for patients with gait disorders that function in any environment, i.e. outside of a gait lab or in magnetically distorted environments.
BACKGROUND: The foot progression angle is an important measure used to help patients reduce their knee adduction moment. Current measurement systems are either lab-bounded or do not function in all environments (e.g., magnetically distorted). This work proposes a novel approach to estimate foot progression angle using a single foot-worn inertial sensor (accelerometer and gyroscope). METHODS: The approach uses a dynamic step frame that is recalculated for the stance phase of each step to calculate the foot trajectory relative to that frame, to minimize effects of drift and to eliminate the need for a magnetometer. The foot progression angle (FPA) is then calculated as the angle between walking direction and the dynamic step frame. This approach was validated by gait measurements with five subjects walking with three gait types (normal, toe-in and toe-out). RESULTS: The FPA was estimated with a maximum mean error of ~ 2.6° over all gait conditions. Additionally, the proposed inertial approach can significantly differentiate between the three different gait types. CONCLUSION: The proposed approach can effectively estimate differences in FPA without requiring a heading reference (magnetometer). This work enables feedback applications on FPA for patients with gait disorders that function in any environment, i.e. outside of a gait lab or in magnetically distorted environments.
Authors: Pete B Shull; Rebecca Shultz; Amy Silder; Jason L Dragoo; Thor F Besier; Mark R Cutkosky; Scott L Delp Journal: J Biomech Date: 2012-11-10 Impact factor: 2.712
Authors: Angelos Karatsidis; Rosie E Richards; Jason M Konrath; Josien C van den Noort; H Martin Schepers; Giovanni Bellusci; Jaap Harlaar; Peter H Veltink Journal: J Neuroeng Rehabil Date: 2018-08-15 Impact factor: 4.262