Ambulatory human upper limb joint motion monitoring

In order to make an ergonomic analysis of laborer working conditions, we need to measure the different joint angles along the daily work. These angles will be used to define the requirements of each workstation. This information, together with the medical examination of each worker, is then used to determine whether a worker can develop a task, or if the task may have caused an occupational disease. Usual human motion capture systems are designed to work in laboratory controlled conditions. This paper presents a method of angular joint measurement, combining inertial sensors (accelerometers and gyroscopes) and magnetic sensors, which allows the ambulatory estimation of the 7 degrees of freedom of the upper limb, for a long time, without problems due to time integration of the signal.