3D human motion capturing based only on acceleration and angular rate measurement for low extremities

Human motion capturing is used in ergonomics for ambulatory assessment of physical workloads in field. This is necessary to investigate the risk of work-related musculoskeletal disorders. Since more than fifteen years the IFA is developing and using the motion and force capture system CUELA, which is designed for whole-shift recordings and analysis of work-related postural and mechanical loads. A modified CUELA system was developed based on 3D inertial measurement units to replace all mechanical components in the present system. The unit consists of accelerometer and gyroscopes, measuring acceleration and angular rate in three dimensions. The orientation determination based on angular rate has the risk of integration errors due to sensor drift of the gyroscope. We introduced “zero points” to compensate gyroscope drift and reinitialize orientation computation. In a first evaluation step the movements of lower extremities are analyzed and compared to the optical motion tracking system Vicon.