Development of Optical 3-axis Distributed Forces Sensor for Walking Analysis

This paper presents development of a novel optical forces sensor which can measure 3-axis distributed forces of a sole during walking. The 3-axis distributed forces have not been noticed at conventional researches of walking analysis. The developed sensor can measure how much force in which direction a sole loads the floor in detail when human walks. The construct of the 3-axis distributed forces sensor using silicone´s rubber is reported. To measure the 3-axis distributed forces, a sheet of silicone´s rubber which has a number of circular truncated cone projections is designed and developed The relation between the force and the deformation of a projection measured by High-speed cameras is verified with the developed sheet of silicone´s rubber. A vertical force is detected from the change in the contact area of a projection. A horizontal force is detected from the distance between centers of gravity on circles of a projection. Thus, the 3-axis distributed forces can be measured from the deformation of projections.