Gait patterns in standard scenarios: Using Xsens MTw inertial measurement units

The paper deals with the determination of 3D gait patterns of the lower limbs and the pelvis as a result of experiments in standardized scenarios. In the experimental setup seven synchronized Xsens MTw inertial measurement units (IMU) are applied to the lower limbs and the pelvis of the subject. The sensors provide filtered and strapped down samples of acceleration, angular velocity and magnetic rate vectors as well as the estimated quaternion of orientation. The data are transferred with a rate of 60 Hz and transformed into an inertial coordinate system. Stable and reliable algorithms processing the gait data and calculating gait features of a single sensor are developed and evaluated. These algorithms are based on precise determination of each gait cycle. In the middle of stance phase the foot is not moving. It stands on the floor and, following, the initial conditions for the calculation of foot velocities and distances by integration are predetermined. The same time intervals are used for calculations of the data of the other sensors fixed to the shank, thigh and pelvis. Investigating the averaged motion of different cohorts in various standard scenarios gait patterns were determined and compared with patterns given by Perry and Murray [1,2].