Using sequences of movement dependency graphs to form object categories

This paper describes a new graph-based representation that captures the interaction possibilities between the robot´s hand and one or more objects in the environment in terms of the dependencies between their movements or lack of movements. The nodes of the graph correspond to the tracked visual features, i.e., the robot´s hand and the objects. The edges correspond to the pairwise movement dependencies between the features. As the robot performs different behaviors with the objects the structure of the graph changes, i.e., edges are added and deleted over time. This paper tests the hypothesis that sequences of such graphs can be used as a signature that captures the essence of some object categories. This framework was tested with container and non- container objects as the robot tried to insert a small block into them. The results show that the robot was able to distinguish between these two object categories based on the sequences of their corresponding movement dependency graphs.