Development of Motion Control Algorithm of Walking Support Robot Based on User-Robot Positional Displacement

Abstract

The purpose of this study is to develop motion control algorithm of a walking support robot to prevent user's fall by measuring relative distance between the user and the robot. The proposed algorithm is composed of following three steps: (i) User's walking stability which is computed based on the center of gravity is evaluated by two discriminant functions which estimate the user's walking posture. The discriminant functions are obtained by performing discriminant analysis on the distance data between representative points of the user's body and the robot. (ii) The robot warns the user by lightning LED lights to make the user recognize the unstable walking state according to the detection of his/her unstable walking posture based on the result of the walking stability evaluation. (iii) The robot prevents the user's fall and assists the user's motion to stabilize the user's walking posture. To confirm the effectiveness of the proposed algorithm, fall prevention experiments are conducted with the experimental system which simulates a human walking motion by using a humanoid doll and an arm robot. The results of experiments show that the proposed algorithm is effective for the fall prevention of the user.