The System Design of an Autonomous Mobile Welding Robot

The welding robot system designed in this paper is helpful to realize welding automation. The closed loop control system and algorithm of arc rotating speed have been designed, so arc rotating speed was stabilized near the set value and the tracking accuracy of fillet weld has been improved by the rotating arc sensor. A data acquisition system and a motion control system have been designed based on multi-sensor technology. The mapping relationship between the features in the welding seam image and the pose of the welding gun was established, so as to realize the identification of the pose of the welding gun based on three-wire laser vision sensing technology. The effect of wire extension, welding currents and welding voltages on the current waveform was investigated based on the rotating arc sensor. By using the designed system and algorithm, the welding deviations recognition experiment, the arc rotating speed control experiment and the tracking experiment of the right-angle welding seam have been carried out. The experimental results showed that the welding deviations were located within [Formula: see text][Formula: see text]mm, and the welding robot can track the complex welding seam accurately and reliably.

Mechanical properties and microstructural characteristics of rotating arc-gas metal arc welded carbon steel joints

The main problem associated with high thickness carbon steel plate's narrow range or “V” groove welding in conventional welding processes is the sagging of the molten pool due to gravity, which in turn leads to defects formation and deteriorates mechanical properties. This problem could be overcome by the rotating arc gas metal arc welding (RA-GMAW) technique. This investigation aims to evaluate mechanical properties and metallurgical characteristics of high thickness IS2062 Gr-B carbon steel joints welded by RA-GMAW technique. The experimental results show that RA-GMAW joint exhibited higher (598 MPa) tensile strength, higher hardness (220 HV) at weld metal region, and lower impact toughness (137 J) than the unwelded base metal. This is due to the presence of fine acicular ferrite and widmanstatten ferrite matrix mixed with fine lamellar pearlite microstructure in the weld metal region.