Development of variable stiffness gel spats for walking assistance

In a previous study we developed an expansion and contraction actuator using PVC gel. We investigated the characteristics of the PVC gel actuator and found that its stiffness changed noticeably with a variation in the applied DC field. In this study, we designed new variable stiffness spats for walking assistance by incorporating the variable stiffness PVC gel actuator in generally used spats. The stiffness of the spats can be varied with the on and off switching of an electric field. We believe that the spats can assist walking by restraining and releasing body motion with different stiffness while walking, and conducted experiments to evaluate their effectiveness. It was found that the integrated electromyogram (IEMG) and maximal voluntary contraction (%MVC) of the rectus femoris muscle decreased during walking when wearing them which indicated that the gel spats designed in this study were effective in assisting walking.