Navigation templates: mediating qualitative guidance and quantitative control in mobile robots

Navigation Templates, a set of tools for constructing flexible plans for a mobile robot's local navigation, is described. A Navigation Template-based plan for action is environment-relative. The plan places qualitative constraints on the robot's actions as a function of the robot's internal model of its surroundings. Because these constraints bound the robot's motions, rather than dictating a particular trajectory, the plan is able to flex with the robot's changing perceptions of the world. Quantitative actuator control is obtained through the use of a transformation function that maps the qualitative plan into a currently preferred direction of travel for the robot. The transformation is computationally inexpensive, allowing the quantitative control to be updated rapidly, thus keeping the robot's actions in step with the qualitative plan and its perceptions of the world. This work is implemented and running on the Jet Propulsion Laboratory's planetary exploration mobile robot as well as MITRE's Denning mobile robot.<
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