Research On Seam Tracking System Based On The Dual Probe Eddy Current Sensor

With the development of our modern society, the automation and intellectualization of wielding becomes necessary. The automatic tracking of welded joint is a key problem while the sensor technology is crucial to realize the tracking. This article designs a dual probe eddy current sensor to compensate for the shortcomings of the conventional eddy current sensor, This sensor can detect variation of height and area simultaneously, and can separated the impact of both. The essay will combine the sensor with the weld tracking. The technology can can realize an arrow gap butt plate with lap seam tracking and overcome the problem of misalignment by using this sensor to detect the change of area. At the same time, the author designs impedance normalization method to eliminate the influence of the eddy current sensor electromagnetic properties of materials, and provide a new method for tracking welding dissimilar materials automatically.Firstly, this paper presents a dual probe eddy current sensor based on advantages and disadvantages of the conventional eddy current sensor, and analysis the detection principle of the sensor,get the eddy current sensor coil impedance calculation formula and its influencing factors by analyzing, and take a preliminary study of the impact and the relationship between them., Analyzed dual probe eddy current sensors at the same time how to detect and extract the signal change of distance and area. According to the coil impedance formula indicates and the characterization of the eddy current sensor, we can know that, Electromagnetic properties of the material to be welded have a greater impact on the output of the eddy current sensor, This effect limits the application of the eddy current sensor, especially applied in the field of automatic seam tracking, It is difficult to use eddy current sensors to achieve welding between different electromagnetic properties of materials automatically track. To solve this problem, proposed the Impedance normalization method method to eliminate the influence of the eddy current sensor electromagnetic properties of materials, to expand the application of the eddy current sensor, propose a method for automatic tracking welding dissimilar materials.From eddy current sensor seam tracking system, we can know that affecting the sensor output signal there are two main factors, height and area. analyzed the experimental data model by BBD experimental design, verifying the significant of two factors, the conventional eddy current sensor cannot detect the signal change caused by two factors, the need to introduce dual probes eddy current sensor. Through response surface methodology analysis, get response surface, by fitting response surface can get a response equation. Separating two variable to detecting the changes of two variables, to achieve seam tracking based on dual probe eddy current sensor.Finally, the author introduced the tracking control method of the seam tracking system based on dual probe eddy current sensor. Designed the hardware and software of the system, Using the oretical analysis to the actual seam tracking experiment, The experimental results show that the system can achieve seam tracking.