The proposed PhD thesis aims to develop an adaptive control module for high-performance remote-laser welding systems. These systems require precise determination of the weld path and control of the laser beam power to achieve the desired weld quality, which involves simultaneous synchronization of the movement of the robotic arm, the laser beam along a relatively arbitrarily shaped trajectory, and the corresponding change of laser power. Manual teaching of remote-laser welding systems is a tedious and inaccurate process, due to the narrow diameter of the laser beam at the focal position, as well as factors such as inexact workpiece geometry, unreliable clamping, and deformations that occur during welding. The proposed control module addresses these issues by employing a triangulation feedback control loop and coaxial structured illumination of the interaction zone to determine accurately and simultaneously the 3D position of the weld path and laser beam, and the size of the interaction zone. Two calibration methods are implemented for this control method, including positioning the control module in space and determining the relationship between welding power, speed, and penetration depth. In the results, we compared different ways to control the position and power of the laser beam. Experimental results demonstrate beam position accuracy of less than 0.05 mm, which is four times better than the resolution of the human eye. With the same module, by controlling the laser power, we can ensure a constant penetration depth with a standard deviation of less than 0.1 mm, while also reducing the occurrence of plasma bursts.
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