Robotic Hand-Free-Stick for Walking Balance Assistance

This paper proposes a wearable robotic stick for walking assistance, called "Hand-Free-Stick" (HFS), for people with non-serious dysfunction in their gait. The basic idea of the proposed HFS is to enlarge ZMP (Zero moment point) area of a user under hands free conditions and to augment his/her body balance ability in walking. A boots type prototype of the HFS is developed with a lightweight robotic stick using a servomotor, in which the slider-link mechanism works to regulate the stick angle and length at the same time. The stick motion is controlled by a single-board computer based on the distribution of foot/feet pressures measured by the sensor system using eight load cells attached at the sole of boots. A set of walking tests with/without the prototype of HFS is carried out for four healthy subjects and demonstrates the effectiveness of the proposed HFS to expand the ZMP area leading to walking balance assistance.