Ankle Joint Moment Estimation Based on Smart Shoes

Abstract For analyses and diagnoses of a human gait, the precise measurement of ground reaction forces (GRFs) is essential, because the GRF is the most significant external force in the human body dynamics. The GRF is not only useful information by itself, but also utilized to obtain further useful information, such as the center of pressure (CoP) and the joint moments. For this purpose, a force plate and an optical motion capture system have been considered as a gold standard. However, the force plate is inconvenient due to its spatial limits. To overcome the limitation of force plates, Smart Shoes that measure the GRFs by four air-pressure sensors embedded in silicone insoles are used to measure the GRFs in this paper. Then, the dynamic characteristics of the ankle joint are modeled and used to estimate the ankle joint moments from the Smart Shoes measurement. The performance of the proposed method is verified by experimental results with a human subject.