Vibration analysis of pipeline welding robot

Objective The study aims to investigate the vibration characteristics of robots under various working conditions and identify the key factors contributing to vibration, thereby providing optimization strategies to ensure the stable operation of robots. Methods The CPP900-W2N pipeline welding robot was selected as the experimental subject. Piezoelectric vibration acceleration sensors were employed to collect vibration parameters from different positions of the robot under diverse working conditions. Data processing was conducted using Matlab, and the vibration signals were analyzed through time-domain waveform analysis, statistical parameter analysis, and frequency-domain analysis methods. Results The findings revealed that the vibration frequency components at each measurement point on the robot were similar, predominantly featuring 50 Hz and its harmonic frequencies. These frequency components remained constant across different operating conditions, and the amplitude of the primary frequency components increased with the robot’s speed. During rapid retraction and rapid advancement, the root mean square (RMS) values of total acceleration at the four measurement points were higher than those observed under other conditions, with the primary vibration source being the welding gun in the x-direction. Under hot pass, filler pass, and cap pass conditions, the RMS values of total acceleration at the four measurement points were comparable and relatively low, with the main vibration source being the robot body in the z-direction. As the pipeline radius increased, the vibration generated by the robot progressively decreased. Conclusion The vibration signals of the welding robot exhibit abrupt changes followed by stabilization in response to variations in operating speed. The predominant vibration frequencies are 50 Hz and its harmonics, which remain unaffected by working conditions. The primary sources of vibration differ under various working conditions. During welding operations, the main vibration source is the robot body in the z-direction, whereas during rapid movement, it is the welding gun in the x-direction. A positive correlation exists between operating speed and vibration, while a negative correlation is observed between pipeline radius and vibration.