A clinical pilot study on posture stabilization via light contact with cane-type companion robot

Shunki Itadera,Tadayoshi Aoyama,Yasuhisa Hasegawa,Kenji Kato,Izumi Kondo,Keita Aimoto

doi:10.1186/s40648-019-0145-y

Shunki Itadera, Tadayoshi Aoyama + Show 4 more

Open Access

https://doi.org/10.1186/s40648-019-0145-y

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Abstract

In this paper, toward robotic gait assistance, we investigate the feasibility of a cane-type assistive mobile robot accompanying the user autonomously through a clinical pilot experiment. As widely known, gait ability is important for all people to keep their quality of life. However, for people having weakened lower limbs such as elderly people, their postural sway during walking could be insuppressible and cause falling. To support the gait motion of elderly people, our group has been developing a series of hand-holding cane robots named Intelligent Cane. Such assistive robots are expected to remove barriers to the independent lives of elderly people. Recently, we have focused on the potential of a companion robot that follows the user ahead and can be touched or grasped for bracing whenever the user needs it. In order to demonstrate proof of our concept through an experiment with a motion capture system, we propose a user companion strategy that enables our cane robot to keep a constant relative distance between the robot and the user walking on a treadmill. We evaluate the accuracy of the user companion in an experiment where a user walks on a treadmill. Then, we conduct a clinical experiment with three healthy subjects walking on with the treadmill with our cane robot as a pilot study. Through the clinical experiment, we evaluate a postural stabilization effect of physical interaction with the robot and discuss the feasibility of our robotic gait assistance methodology.

Highlights

Increasing elderly population and a shortage of human resources cause that the demand for care exceeds the supply [1]
In this paper, we proposed a user companion algorithm for our cane robot moving on the treadmill with the user in order to investigate the postural sway reduction by slightly touching the robot
We introduced a manual and autonomous motion planning methodologies according to the applied force from the user and the relative position between the robot and the user, respectively

Summary

Introduction

Increasing elderly population and a shortage of human resources cause that the demand for care exceeds the supply [1]. The related papers mentioned above present the assistive devices providing physical support to prevent the users’ falling kinematically or dynamically Such a usual assistive strategy is useful to obtain a numerical balance margin, e.g., the zero moment point, our proposed notion focuses on human medical functionality to reduce the redundant interaction and help the user, who feels a fear to walk slightly, recovers more natural gait motion via light physical contact. The most notable feature of the robot is that its motion trajectory is planned according to the user’s gait intention estimated based on the force applied to the handle and the user’s leg movement measured by the force sensor and the LRF By this trajectory planner, the cane robot can accompany a user and provide a contact point which can be touched whenever the user feels fears during walking.

Result

Results and discussion

Conclusion