Initial Study of Multirobot Adaptive Navigation for Exploring Environmental Vector Fields

Adaptive navigation is the process of modifying a vehicle's direction or path based on measurements taken while moving. Significant work in this area has been performed for scalar fields, in which a single measurement such as temperature or the concentration level of a pollutant is associated with every point in the field; scalar field capabilities that have been developed include control strategies for finding local extrema, moving along contour lines, and navigating along ridges/trenches within a field. One can imagine the ability to perform similar maneuvers in flow fields, in which a vector quantity such as fluid flow is associated with each point in the field. In such a field, various applications could benefit from the ability to navigate to/along vector field primitives such as sources, sinks, vortices, uniform fileds, and combinations of them. In this paper, we propose several simple control strategies for a multirobot formation to navigate to/along such features. Each technique is explained, and we describe how each can be implemented in a multilayer control system in which adaptive navigation commands are issued to a multirobot formation control layer, which in turn issues directives to individual robots. Simple simulation case studies are used to demonstrate the behavior of each control technique. Finally, we also describe initial work in preparing for experimental demonstration of these techniques using a cluster of automated surface vessels to demonstrate the techniques in the field.