Inspection planning for sensor coverage of 3D marine structures

Abstract

We introduce an algorithm to achieve complete sensor coverage of complex, three-dimensional structures surveyed by an autonomous agent with multiple degrees of freedom. Motivated by the application of an ocean vehicle performing an autonomous ship hull inspection, we consider a planning problem for a fully-actuated, six degree-of-freedom hovering AUV using a bathymetry sonar to inspect the complex structures underneath a ship hull. We consider a discrete model of the structure to be inspected, requiring only that the model be provided in the form of a closed triangular mesh. A dense graph of feasible paths is constructed in the robot's configuration space until the set of edges in the graph allows complete coverage of the structure. Then, we approximate the minimum-cost closed walk along the graph which observes 100% of the structure. We emphasize the embedding of observations within the edges of the graph as a means of utilizing all available sensor data in planning the inspection.