A low-cost mockup to simulate robotic laser cutting in nuclear decommissioning

TL;DR

This paper presents a low-cost mockup for simulating robotic laser cutting in nuclear decommissioning, featuring a constrained motion controller that compensates for inaccuracies and avoids collisions.

Contribution

The study introduces an innovative, low-cost experimental setup with a constrained task-space adaptive controller for collision avoidance and improved laser path tracking.

Findings

Achieved mean accuracy of 3.9 mm with end-effector pose control.

Achieved mean accuracy of 2.4 mm with ultraviolet beam control.

System effectively compensates for parameter inaccuracies and avoids collisions.

Abstract

This paper introduces a low-cost experimental mockup to simulate the laser cutting process of containers in nuclear decommissioning. It is composed of a three-axis table supporting a cuboid container with ultraviolet-sensitive faces, a six-degree-of-freedom serial manipulator holding an ultraviolet torch that simulates the laser, and a visual system based on cameras and fiducial markers. The system employs a constrained task-space adaptive motion controller that compensates for inaccurate parameters and eliminates the need to calibrate the system. Furthermore, as the motion controller explicitly accounts for geometric constraints, the robot reactively avoids collisions with obstacles while handling the ultraviolet torch. To enhance tracking of the laser-cutting path, we control the ultraviolet beam, which requires only four degrees of freedom, instead of the full end-effector pose. Experiments show that, despite an initially uncalibrated system, the overall system is capable of tracking different trajectories with an overall mean accuracy of 3.9 (sd 2.5) mm when the end-effector pose is controlled and 2.4 (sd 1.3) mm when the ultraviolet beam is controlled.