Application of Inertial Measurement Units for angular motion detection

Abstract

Inertial Measurement Units (IMU) are applied as a new tool to acquire information regarding human joint motion. In order to better understand and acquire accurate measurements, one must be certain that the equipment is accurate. This study was designed to test the validity of our developed IMU system with regards to both statics and dynamics. Our developed IMU system was compared using standard reference angles and a standard three dimensional (3D) camera system. The results showed that the absolute average of the differences between the reference angles and our IMU measurements in the static testing were 1.44±0.76 degrees on sensors no. 1&2 and 1.44±2.63 degrees on sensor no. 3&4 in the sagittal plane. In the coronal plane, they were 1.19±0.45 degrees and 1.58±0.41 degrees, respectively. For the dynamic testing, angular outputs from our developed IMU sensors no. 1&2 compared to the angular outputs from the 3D camera system had the range of differences within ±4 degrees when testing in the sagittal and coronal planes. The angular outputs from sensor no. 3&4 had a range of differences within ±5 degrees. In conclusion, our developed IMU system was proven to be accurate in both static and dynamic testings in both planes.