Novel walking assist device based on generic human motion tracking criteria

Replacing nurses and caregivers by human-friendly robots is drawing the attention of the next generation for elderly people assistance and those with special needs. However, the human-machine cooperative control is still a key challenge in this domain. This paper presents a new approach for walking assist control that uses Inertial Measurement Units (IMUs) fixed on elderly people's body to track their posture and estimate its Center Of Mass (COM) and Zero-Moment Point (ZMP) motions to be used by a differential mobile robot that synchronize with the user's walking motion. Furthermore, a manipulator mounted on the mobile device to support the users from their back, help them walk, and assist in dangerous situations. In this study, the walking is divided into phases according to the falling index defined, and the impedance of the manipulator is changed based on the stability of the situation. Experiments of the walking assist control were carried out, and by their results the validity of the proposed approach is confirmed and the fall avoidance is realized.