Inspection Planning for Sensor Coverage of 3d Marine Structures

Brendan Englot and Franz Hover

Presented by Arvind Pereira for the CS599 Class on Sequential Decision Making in Robotics

Objective

• Algorithm to achieve complete sensor coverage of complex 3-d structures when surveyed by an autonomous agent with multiple degrees of freedom

• Motivating application is ship-hull inspection using bathymetric sonar

• Plans on a closed triangular mesh model of the structure being inspected

Related Work

• Art Gallery Problem – Minimum # of guards who can together observe the entire gallery

• Car painting/Building inspection – Specific geometry of structure being covered

• Challenging issues in Computational Geometry for complex 3-d models in the absence of a priori knowledge

Related Work

• Sampling-based planning for similar problems employed the “art gallery” approach i.e. choosing a set of configurations which offer complete coverage and finding a feasible tour among these nodes

• Postman Framework – information efficient approach to solve deterministically-designed inspections for point robots in a 2-d workspace when robot has a small FOV relative to the size of the workspace

Sensor Footprint of a bathymetric sweep

Graph Construction Algorithm

Find Neighbors

Add Missing View to Graph

Add To Graph

Connect Subtours

Path-Finding AlgorithmIncidence Matrix

for flows

Constraint Matrix ensuring that all

nodes are inspected by a chosen path

Constraint that enforces the

initial node is on the graph

Structure Models

Dense Graphs for Examples

Paths Found

Subtour Connection

Algorithm Performance

Conclusion

• Algorithm ensures coverage planning over arbitrary discrete 3D structures using an information-efficient postman formulation

• Need to be more efficient in the search for feasible views

• Want to optimally manage the division between graph construction and path-finding