RobVision: vision based navigation for mobile robots

This paper introduces the system, developed during the Esprit project RobVision (robust vision for sensing in industrial operations and needs), that navigates a climbing robot through a ship section for inspection and welding tasks. The basic idea is to continuously generate robot position and orientation (pose) signals by matching the visual sensing information from the environment with predetermined CAD-information. The key for robust behaviour is the integration of two different vision methods: one measures the 3D junctions with a stereo head, the other tracks the edge and junction features in a single image. To render robust and fast tracking, a model knowledge such as the feature topology, object side, and view dependent information is utilised. The pose calculation step then integrates the finding of both vision systems, detects outliers and sends the result to the robot. The real-time capability is important to reach an acceptable performance of the overall system. Presently a pose update cycle time of 120 ms has been achieved. Due to appearing jerks of the robot accelerometers were used for stabilization. Experiments show that our approach is feasible and meets the required positioning accuracies.