Simulations have traditionally been used as off-line tools for examining process models and experimenting with system models for which it would have been either impossible or too dangerous, expensive, or time-consuming, to perform with physical systems. We propose a novel way of regarding simulations as part of both the development and the working phases of systems. In our approach simulation is used within the processing and control loop of the system to provide sensor and state expectations. This minimizes the inverse sensory data analysis and model maintenance problems. We refer to this mode of operation as the verification mode, in contrast to the traditional discovery mode. In order to provide simulations and planning that are intertwined with the control of a physical system, temporal issues have to be considered. By limiting the focus of the system to small portions of complex models which are temporarily relevant to the system’s operation, the system is able to maintain its models and respond faster. For this we employ the Context-based Caching (CbC) mechanism within our Mobile Platform Control and Simulation Program (MOSIM). CbC is a knowledge management technique which maintains large knowledge bases by making the necessary information available at the right time.

Pose determination for robot navigation is discussed. The problem is to maintain the system's instantaneous precept of its position and orientation in space for performing various tasks. The authors describe a system in which models were used to guide the sensory interpretation and to correct expectations. In this system, simulated images were used to analyze the real images and to correct the pose parameters. The reported techniques have been implemented and experiments with real images in a real environment have been performed.>