Estimation of floor reaction force during walking using physical inertial force by wireless motion sensor

Abstract

Floor reaction force is widely used to evaluate walking. Generally, floor reaction force is measured by a floor reaction meter. However, floor reaction meter is not suitable for clinical practice due to the limitation in walk condition, measurement range and device size. This study suggests a simple method to estimate floor reaction force by processing dynamic acceleration information to be provided from small wireless motion sensors. In the experiment, optical motion capture and the floor reaction meter were used. The result shows that the sum of the inertial force of the whole body and gravity equal floor reaction force obtained through an experiment using optical motion capture. We consider that physical inertial force of the whole body could be estimated from the dynamic acceleration of the lower trunk and right/left thighs. A similar result obtained with the motion sensor. An estimation of floor reaction force by measuring the inertial force is effective, and much simpler walk analysis could be possible with using appropriate signal handling of wireless motion sensor information. This method can be applied to biofeedback.