The colorimetric method for real-time measurement of temperature field using ICCD as sensor was devel-oped. In order to ensure the accuracy and sensitivity, the relationship between the ratio response of two-color imagesand radiant property of body, transmission property of filter, spectral response of ICCD is discussed. The analysis isbased on computer calculation of the established mathematical model. On the basis of the analysis, optimum wave-lengths are obtained for a given sensor system. Experimental work was carried out to check the correctness of the theo-retical results. The method is useful for general purpose of study and design of the developed system.

Due to violent disturbance of the welding arc, signal processing is the key problem of ap-plication of the sensor. By means of the new technique the arc sensor can recognize not only V-groove but also lap joint and butt joint. The sensor has good recognition ability even for welding process with very large current disturbance, e.g. pulsed arc and short circuit welding process, etc. The proposed technique is developed on the basis of modern digital filtering theory and mathematic transformation of the signals from time domain into frequency domain.

The real-time measurement of welding temperature field by colorimetric method is described, and with the data acquired from it closed-loop control system of the parameters of temperature field is developed and tested. Ex-perimental results prove that it has high measurement speed (time of a field within 0.5s) and good dynamic response quality. Weld penetration can be controlled satisfactorily under unstable welding condition.

Arc sensor, one of the most popular and effective sensors for automatic seam tracking of arc welding, is systematically studied. A mathematic model of the static and the dynamic properties of the sensor derived on the basis of control theory and experimental method are described. The model extends our understanding of arc sensor from qualitative level to quantitative level. This is important for its design and further development.