| This dissertation addresses the need for an intelligent sensor fusion system for autonomous mobile robots. The research discussed in this dissertation focuses on modeling a control scheme for a sensor fusion system. The control scheme is of prime interest because it defines the constituent elements of sensor fusion, their responsibilities, and interactions. The overall direction of this research is characterized by the action-oriented perception paradigm. In this paradigm all perceptual processes are examined in terms of their perceptual context: the action to be performed, the sensing capabilities, and the impact of the environment.; The contributions of this research to robotics are grouped into four areas: the state-based control scheme, the execution mechanism, the computation theory, and the SFX architecture as a whole. The state-based control scheme is derived from insights from cognitive and behavioral psychology. It organizes sensors around fusion states, which represent the ability of the system to detect and control potential discordances or sensing anomalies. The response to a discordance is either feedback or exception handling. The execution mechanism makes use of Dempster-Shafer theory for uncertainty management. The computational theory of sensor fusion provides defines sensor fusion with multiple levels of abstraction, making fusion easier to understand; defines what types of information need to be represented and how it will be accessed; and guides the development of mechanisms for performing the activities involved in sensor fusion. It also offers a perceptual grammar for specifying the composition of a percept and an observational grammar for transfer of belief. The SFX architecture serves as a blueprint for the implementation of the ideas developed in this dissertation. The input to SFX is a set of sensing plans supplied by the designer; the sensing plans tailor the generic fusion process for a specific percept.; Thirteen experiments were conducted with the Georgia Tech mobile robot, a Sony Hi8 color video camera, a Pulnix b&w video camera, an Inframetrics true infra-red camera, and Polaroid ultrasonics. The experiments demonstrate the utility of fusion states, the detection of state failures, and the transfer of belief using the Dempster-Shafer evidential representation. |
