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

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.