A Novel Plasma Cutting Articulated Robot System with Torch Angle Sensor and Its Applications in Industry

This paper presents a novel plasma cutting articulated robot system with torch angle sensor to cut the large structural steel workpiece instead of the less flexible conventional CNC cutting machine. One critical aspect of plasma cutting task by utilizing an articulatell robot is to ensuring the correct angle between the cutting torch and the workpiece. To address these challenges, we proposed an IMU-basell wireless sensing system for the real-time angle detection and alignment. We integrated two wireless IMUs to accurately determine the relative angle between the cutting torch and workpiece. One IMU is attached to the cutting torch, while the other is mounted on the workpiece, enabling precise real-time angle measurements. A dedicated smartphone app installed on the tablet computer collects the IMU orientation data, performs calibration, and computes the relative angle with 3-D visualization in real time. To verify the capability of proposed system, we conducted a 45° bevel cutting experiments to compare the cutting result and robot teaching time between the proposed method and the conventional jig measuring method. As the results, the proposed system can achieve high-precision bevel cutting with an error of only 0.03°, while the conventional method has an error up to 5.26°. The results also show that the robot teaching time using the proposed method is 1.55 times faster than the conventional method. In addition, to confirm its practical application in industry, we successfully applied the proposed system in plasma cutting of the large structural steel beams with vertical cutting, cross-section and bevel cutting.