TY - JOUR

T1 - IMU-based joint angle measurement for gait analysis

AU - Seel, Thomas

AU - Raisch, Jörg

AU - Schauer, Thomas

N1 - Acknowledgments The authors are indebted to Timo von Marcard, Bettina Westebbe and Julius Thiele, as well as to Thomas Schmalz and his team for their excellence and cooperation before, during and after the gait experiments. Furthermore, we gratefully acknowledge Steffen Schäperkötter’s skillful support in programming and data evaluation. We sincerely thank the subject of the gait trials for letting us record inertial data during his examination in the optical gait lab. Finally, we thank Celine Sin for her valuable advice on language and style. As part of the research project, mebGO, this work was supported by the German Federal Ministry of Education and Research (FKZ 01EZ1112).

PY - 2014/4/16

Y1 - 2014/4/16

N2 - This contribution is concerned with joint angle calculation based on inertial measurement data in the context of human motion analysis. Unlike most robotic devices, the human body lacks even surfaces and right angles. Therefore, we focus on methods that avoid assuming certain orientations in which the sensors are mounted with respect to the body segments. After a review of available methods that may cope with this challenge, we present a set of new methods for: (1) joint axis and position identification; and (2) flexion/extension joint angle measurement. In particular, we propose methods that use only gyroscopes and accelerometers and, therefore, do not rely on a homogeneous magnetic field. We provide results from gait trials of a transfemoral amputee in which we compare the inertial measurement unit (IMU)-based methods to an optical 3D motion capture system. Unlike most authors, we place the optical markers on anatomical landmarks instead of attaching them to the IMUs. Root mean square errors of the knee flexion/extension angles are found to be less than 1° on the prosthesis and about 3° on the human leg. For the plantar/dorsiflexion of the ankle, both deviations are about 1°.

AB - This contribution is concerned with joint angle calculation based on inertial measurement data in the context of human motion analysis. Unlike most robotic devices, the human body lacks even surfaces and right angles. Therefore, we focus on methods that avoid assuming certain orientations in which the sensors are mounted with respect to the body segments. After a review of available methods that may cope with this challenge, we present a set of new methods for: (1) joint axis and position identification; and (2) flexion/extension joint angle measurement. In particular, we propose methods that use only gyroscopes and accelerometers and, therefore, do not rely on a homogeneous magnetic field. We provide results from gait trials of a transfemoral amputee in which we compare the inertial measurement unit (IMU)-based methods to an optical 3D motion capture system. Unlike most authors, we place the optical markers on anatomical landmarks instead of attaching them to the IMUs. Root mean square errors of the knee flexion/extension angles are found to be less than 1° on the prosthesis and about 3° on the human leg. For the plantar/dorsiflexion of the ankle, both deviations are about 1°.

KW - Avoid magnetometers

KW - Exploit kinematic constraints

KW - Gait analysis

KW - Gyroscopes and accelerometers

KW - Inertial measurement units

KW - Joint angle measurement

KW - Joint axis and position identification

KW - Sensor-to-segment mounting

KW - Validation against optical gait analysis

KW - Validation on prosthetic and human leg

UR - http://www.scopus.com/inward/record.url?scp=84898957836&partnerID=8YFLogxK

U2 - 10.3390/s140406891

DO - 10.3390/s140406891

M3 - Article

C2 - 24743160

AN - SCOPUS:84898957836

VL - 14

SP - 6891

EP - 6909

JO - Sensors (Switzerland)

JF - Sensors (Switzerland)

SN - 1424-8220

IS - 4

ER -