Using concrete, perceptually based representations to avoid the frame problem*

Real-world planners must be able to temporally project their external actions internally. Typically, this has been done entirely at an abstract representational level. We investigate an alternative approach, performing projections on a concrete, property-based representation, and rederiving the abstract level from it. We show that this approach can greatly alleviate the frame problem in certain types of spatial domains, while maintaining the advantages of planning at an abstract level. We present a comparison of the approaches in various object-manipulation domains, including the results of a re-implementation of the Robo-Soar system [Laird et al., 1989].