Development of a dynamic beam stabilization system for a six-axis ultrashort pulsed laser robot

Abstract We report on the evaluation of a beam stabilization system mounted on a six-axis articulated ultrashort pulsed laser robot system for real 3D micromachining. The system integrates a discrete beam guiding system along the robot links and an optical scanner mounted on the final robot axis, enabling high-speed laser scanning for material processing with high power femtosecond pulses. For true 3D micromachining, the robot positions and orients the scanner, allowing scan fields to be stitched or different workpiece areas to be addressed through robot movement. A cascaded beam stabilization system is developed for beam linear and angular position drift correction. This system is implemented on robot links that extend from the robot axis with an integrated ultrashort pulsed laser to the axis with the scanner. The first stage stabilization stabilizes the beam position drift induced by the movement of the axes preceding the laser-integrated axis, as well as the axis equipped with the laser. The second stage is responsible for stabilizing the beam drift resulting from the following axes. A dynamic beam stabilization algorithm including beam position detection and correction with combining the current robot position is introduced and discussed. The stabilization is applied to correct the beam drift after the robot has reached the desired target position for the following scanner movement. In addition, a neural network prediction model is developed and implemented on the system, which reduces the half correction time and increases the beam drift correction efficiency.