What Stands-in for a Missing Tool? A Prototypical Grounded Knowledge-based Approach to Tool Substitution

It is not uncommon to find a tool needed for a certain task unavailable. However, humans tend to circumvent such hurdle by improvising the usability of a suitable existing object in the environment. For a robot who is expected to work alongside humans in the real word is bound to face such obstacles and an effective way to carry on with the task for it would be to find a substitute. Robots that, for instance, have to hammer a nail into a wall should look for a conventional tool, a hammer, or resort to an appropriate substitute in case a hammer is unavailable. A selection of an appropriate substitute requires a knowledge driven deliberation to determine its suitability. Baber in Baber (2003a) suggested that humans are aided by conceptual knowledge about objects during the deliberation process. In other terms, humans generally have an intuitive understanding of objects and as such use qualitative form of knowledge about properties of objects - thus, conceptual knowledge - obtained from a combination of visual sensations, experiences and the outcomes of manual investigation to evaluate the applicability of a substitute.