Cooperative Behavior of a Mechanically Unstable Mobile Robot for Object Transportation.

Abstract

Cooperative transportation of an object by two or more mobile robots requires each robot to exert an appropriate force to support and move the object, to move along the object, and to maintain the robot's attitude stably. Studies of cooperative transportation by multiple robots so far have scarcely considered the stability of the robot's attitude influenced by the force from the object. To take part in cooperative transportation, a mechanically unstable robot, such as a wheeled inverted pendulum, needs to control the force and follow the object while standing stably against the force in an integrated manner. We call this "cooperative behavior". To realize this behavior of a mechanically unstable robot, we built a control system to estimate the external force, maintain standing, and exert a specified force. Experiments were conducted on cooperative transportation between a human and the robot.