TRACKING CONTROL FOR AN OBJECT IN PUSHING OPERATION

In this paper, we consider the problem of making a manipulator push an object on a flat floor with a point of contact to a desired position. A manipulator control method for the object to follow a planned traje ctory is proposed. First, using the given distribution of frictional f orces between the object and the floor, we find a particular point, na med pseudo center, on which the motion of the pushed object can be app roximated by the motion of a wheeled mobile robot on its center. Then, a control rule for the pushing operation is derived by applying a tra cking control rule for a nonholonomic mobile robot at the pseudo cente r. This method makes it possible for the robot to perform the tracking control in the pushing operation. A simulation result shows the effec tiveness of the proposed method. Finally, we present an approach for u sing a mobile manipulator to realize the pushing operation. Experiment al verification of the proposed method was performed and the result is described. (C) 1997 John Wiley & Sons, Inc.