ROS-based 3D on-line monitoring of LMD robotized cells

Laser Metal Deposition (LMD) is a promising technique for fabrication of large metallic parts directly from 3D CAD models. However, the complexity of the process makes it challenging to prevent geometrical distortions and defects to affect the fabricated parts. On-line monitoring and control are fundamental issues to mitigate these problems, but they are not efficiently enough provided by current LMD techniques. As the first step in the development of an efficient unified on-line monitoring and control system for LMD, this paper presents a novel on-line 3D monitoring system for part geometry measurement. The system is capable of working in real-time in robot coordinates, without imposing restrictions to the possible paths, orientations or speed of movement. The use of ROS and the self-calibration method also proposed in the paper provide a flexible, cost-effective solution to easily upgrade current industrial LMD robotized cells. Experimental results support the practical feasibility of the proposed solution.