The Sensory Ego-Sphere as a Short-Term Memory for Humanoids

Abstract

The Sensory Ego-Sphere (SES) is a shortterm memory structure for a robot. The SES records and recalls events that are localized in space or time. It is a database structured as a 2D spherical shell centered on the coordinate frame of the robot, spatially indexed by polar and azimuthal angles. In this paper the geometry and data structure of the SES are described. Motion transformations of the SES are given. The aspects of the SES characteristic of a humanoid are discussed. It is shown how the SES (1) fuses sensory data via spatiotemporal coincidence, (2) recalls the previous position of a specific object in relation to the robot and to other objects, and (3) facilitates localization of the robot with respect to known landmarks. The use of the SES on two humanoids, ISAC at Vanderbilt University and Robonaut at NASA Johnson Space Center, is described.