Insole-Type Walking Assist Device Capable of Inducing Inversion-Eversion of the Ankle Angle to the Neutral Position

In recent years, the aging of society has become a serious problem, especially in developed countries. Walking is an important element in extending healthy life expectancy in old age. In particular, induction of proper ankle joint alignment at heel contact is important during the gait cycle from the perspective of smooth weight transfer and reduction of burden on the knees and hip. In this study, we focus on the behavior of the ankle joint at heel contact and propose an insole-type assist device that can induce the ankle angle inversion/eversion rotation. The proposed device has tilting of the heel part from left to right in response to the rotation of a stepping motor, and an inertial sensor mounted inside controls the heel part to always maintain a horizontal position. The effectiveness of the proposed device is verified by evaluating the amount of lateral thrust of the knee joint of six healthy male subjects during a foot-stepping motion using motion capture system. The results showed that the amount of lateral thrust is significantly reduced by wearing the device with control.