Details
| Original language | English |
|---|---|
| Pages (from-to) | 167-170 |
| Number of pages | 4 |
| Journal | Current Directions in Biomedical Engineering |
| Volume | 3 |
| Issue number | 2 |
| Publication status | Published - Sept 2017 |
Abstract
Inertial Measurement Units (IMUs) are increasingly used for human motion analysis. However, two major challenges remain: First, one must know precisely in which orientation the sensor is attached to the respective body segment. This is commonly achieved by accurate manual placement of the sensors or by letting the subject perform tedious calibration movements. Second, standard methods for inertial motion analysis rely on a homogeneous magnetic field, which is rarely found in indoor environments. To address both challenges, we introduce an automatic calibration method for joints with two degrees of freedom such as the combined radioulnar and elbow joint. While the user performs arbitrary movements, the method automatically identifies the sensor-to-segment orientations by exploiting the kinematic constraints of the joint. Simultaneously, the method identifies and compensates the influence of magnetic disturbances on the sensor orientation quaternions and the joint angles. In experimental trials, we obtain angles that agree well with reference values from optical motion capture. We conclude that the proposed method overcomes mounting and calibration restrictions and improves measurement accuracy in indoor environments. It therefore improves the practical usability of IMUs for many medical applications.
Keywords
- Automatic anatomical calibration, Elbow joint, Kinematic constraints, Sensor-to-segment calibration
ASJC Scopus subject areas
- Engineering(all)
- Biomedical Engineering
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In: Current Directions in Biomedical Engineering, Vol. 3, No. 2, 09.2017, p. 167-170.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Automatic anatomical calibration for IMU-based elbow angle measurement in disturbed magnetic fields
AU - Laidig, Daniel
AU - Müller, Philipp
AU - Seel, Thomas
N1 - Publisher Copyright: © 2017 Daniel Laidig et al., published by De Gruyter.
PY - 2017/9
Y1 - 2017/9
N2 - Inertial Measurement Units (IMUs) are increasingly used for human motion analysis. However, two major challenges remain: First, one must know precisely in which orientation the sensor is attached to the respective body segment. This is commonly achieved by accurate manual placement of the sensors or by letting the subject perform tedious calibration movements. Second, standard methods for inertial motion analysis rely on a homogeneous magnetic field, which is rarely found in indoor environments. To address both challenges, we introduce an automatic calibration method for joints with two degrees of freedom such as the combined radioulnar and elbow joint. While the user performs arbitrary movements, the method automatically identifies the sensor-to-segment orientations by exploiting the kinematic constraints of the joint. Simultaneously, the method identifies and compensates the influence of magnetic disturbances on the sensor orientation quaternions and the joint angles. In experimental trials, we obtain angles that agree well with reference values from optical motion capture. We conclude that the proposed method overcomes mounting and calibration restrictions and improves measurement accuracy in indoor environments. It therefore improves the practical usability of IMUs for many medical applications.
AB - Inertial Measurement Units (IMUs) are increasingly used for human motion analysis. However, two major challenges remain: First, one must know precisely in which orientation the sensor is attached to the respective body segment. This is commonly achieved by accurate manual placement of the sensors or by letting the subject perform tedious calibration movements. Second, standard methods for inertial motion analysis rely on a homogeneous magnetic field, which is rarely found in indoor environments. To address both challenges, we introduce an automatic calibration method for joints with two degrees of freedom such as the combined radioulnar and elbow joint. While the user performs arbitrary movements, the method automatically identifies the sensor-to-segment orientations by exploiting the kinematic constraints of the joint. Simultaneously, the method identifies and compensates the influence of magnetic disturbances on the sensor orientation quaternions and the joint angles. In experimental trials, we obtain angles that agree well with reference values from optical motion capture. We conclude that the proposed method overcomes mounting and calibration restrictions and improves measurement accuracy in indoor environments. It therefore improves the practical usability of IMUs for many medical applications.
KW - Automatic anatomical calibration
KW - Elbow joint
KW - Kinematic constraints
KW - Sensor-to-segment calibration
UR - http://www.scopus.com/inward/record.url?scp=85056604831&partnerID=8YFLogxK
U2 - 10.1515/cdbme-2017-0035
DO - 10.1515/cdbme-2017-0035
M3 - Article
VL - 3
SP - 167
EP - 170
JO - Current Directions in Biomedical Engineering
JF - Current Directions in Biomedical Engineering
IS - 2
ER -