An Active Approach to Characterization and Recognition of Functionality and Functional Properties

Functionality in an object can be defined as its applicability toward the accomplishment of a task. We emphasize and develop an interactive and performatory approach to functionality recovery from sensor data in the context of robotic manipulatory tasks. By analyzing interaction of tool and target object and manipulation tasks as goal-oriented recognition processes, we propose to identify and characterize functionalities of objects. This interaction is not only a means of verification of the hypothesized presence of functionality in objects but also a way to actively and purposively recognize the object. The representation of functionality allows us to extend the recovery process to a hierarchy of functionalities allowing complex ones to be composed from simpler ones. A formal model, based on Discrete Event Dynamic System Theory (DEDS), is introduced to define an interactive task for recovering and describing functionality. To observe and control the recovery process we introduce the notion of piecewise observability of a task by different sensors. This allows the description of a dynamic system in which not all events nor the time of their occurrence may be predicted in advance. An experimental system, with both vision and force sensors, for carrying out the interactive functional recognition is described.