Design and control of a standing-operator mobile robot with avoidance function of collision and falling off

Abstract

This paper deals with design and control of a standing-operator mobile robot. Because the human operator stands on the robot, the required area for the operator is relatively smaller than that for the wheel chair (seated-operator) robot, and freed-up area can be used for passengers and/or transporting objects. In addition, the position sensor used for monitoring the center of gravity of the operator can be used as a man-machine interface controller that enables hands-free operation of the robot as opposed to a joy-stick controller. However, with the proposed standing-operator system, the acceleration of the robot needs to be controlled to prevent the standing operator from toppling over. In addition, collision-avoidance control is indispensable because it is difficult to precisely control motion only by sensing the position of the operator's center of gravity. This paper describes the designs for collision avoidance and the acceleration controller for a standing-operator mobile robot. A general-purpose differential-wheeled structure with casters is employed in this study. Experimental results by several human operations in a corridor with corners demonstrate the effectiveness of the proposed acceleration and collision avoidance controller.