Pushing motion for unknown object by humanoid robot

This paper describes a pushing motion for an unknown object by a humanoid robot. This method deals with an object whose parameters are not known. In order to push the unknown object, the robot motion must be decided according to the object. Therefore, the robot judges whether the unknown object is movable or not. When the robot judges the object is unmovable, the robot stops pushing. On the other hand, when the robot judges the object is movable, the robot continues pushing and walking. When the robot walks during a pushing motion, the influence of the pushing motion may destabilize a walking motion. Therefore, ZMP trajectory is modified by reaction force response before one step. Additionally, cycle time in double support phase is also modified by using sigmoid function. In the result, the heavier the object is, the more slowly the robot moves like a human. With these methods, the robot is able to push the unknown object during walking. Furthermore, even if parameters of the object change, this proposed method is available to continue pushing the object.