Study Of Seam Tracking Based On Micro Plasma Arc

Weld seam tracking and sensing technology plays a very important role in welding automate production and is also a critical factor in weld seam quality. The most common sensing methods till now are vision sensor, tactile sensor and arc sensor, etc. But they all have limitations respectively. The technology of weld seam tracking based on micro plasma arc has some particular merits comparing with traditional tracking means and also is an innovation in seam tracking field. According to the principle of this seam tracking method, a suitable system which can generate non-transferred arc was built by designing a micro plasma arc sensor, an arc generating device and some corresponding equipments.A corresponding signal collection and analysis system was developed. In the signal collection module, the collection of high frequency and large numbers of data was realized. Also, oscillogram show and binary or decimal data saving real-time were actualized. In the signal analysis module, digital filter and some other analysis functions were realized.Through static experiments, changing trend and other properties of arc-length to voltage curve was concluded and explained, then further experiments were carried out to analyse all the influence factors. Among which non-transferred arc current and plasma gas flow were regarded as the main factors to the output. By a series of experiments, the most optimum parameters were concluded. After a summing-up of the foregoing work and results, a steadier arc was produced by making an improvement on the micro plasma arc sensor.Afterwards, by the method of multi-line segments fitting, the work of identification of the joints type and pick-up of the characteristic parameters was performed.