SU1720823A1 - Method to monitor joint being welded - Google Patents

Abstract

This invention relates to the automation of welding processes. The method makes it possible to increase the accuracy of tracking the joint by reducing the influence on the control system of interference from the light radiation of the welding arc. Illuminate the junction zone with two g modulated in antiphase beams of light, the sources of which are placed symmetrically on both sides of the photodetector. The light signal reflected from the junction is recorded by a photodetector oriented to the illuminated junction zone. By the difference in the magnitude of the recorded signal in opposite phases of modulation, the direction of displacement of the joint is determined. By moving the optical system relative to the junction, the absence of a variable component in the signal detected by the photodetector is achieved. 1 il.

Description

This invention relates to the automation of welding processes, in particular, to methods for tracking a welding head behind a joint.

The aim of the invention is to improve the accuracy of tracking the joint by reducing the effect of interference from the light emitted by the welding arc.

This goal is achieved by illuminating the joint zone with two out-of-phase modulated beams of light, the sources of which are placed symmetrically on both sides of the photodetector. The light signal reflected from the junction is recorded by a photodetector oriented to the illuminated junction zone. By the difference in the magnitude of the recorded signal in opposite phases of modulation, the direction of the joint displacement is determined. By moving the optical system relative to the junction, the absence of a variable component in the signal detected by the photodetector is achieved.

Irradiation with a light beam directed across the junction allows for high image contrast, and modulation of the light beam makes it possible to analyze the reflected signal with a sensor that is sensitive only to modulated light, eliminating high-power frontal arcing.

The technical solution makes it possible to significantly approximate the tracking zone to the welding zone, and thereby increase the tracking accuracy.

The method makes it possible to compensate not only for the illumination by the welding arc, but also a change in the reflection coefficient on the surface 1

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the edges being welded, the change in the optical scattering of the gaseous medium.

The drawing shows a diagram of an apparatus for carrying out the method.

The device consists of an optical system, directed by its main optical axis to junction 1. The optical system consists of lens 2, an infrared filter 3 and a photo-receiving device 4 installed in the focus of the lens 2. The photo-receiving device is galvanically connected to an amplifier 5, the output of which is connected to the synchronous input detector 6. The latter is controlled by a generator of 7 rectangular pulses and connected respectively to the direct and inverse outputs of the generator. Two illuminators 8 are respectively connected to the same generator outputs 7 rectangular pulses, located on opposite sides of the joint and directed to the joint, so that the edges being welded cast a shadow. The output of the synchronous detector is connected to a comparator 9, which generates a command to the actuator 10, which provides movement of the welded parts in the direction transverse to the junction.

The device works as follows.

The illuminators 8 radiate in antiphase an aplitud-modulated infrared light, which, reflected from the welded edges of joint 1, passes through lens 2 and filter 3 to the photoreceiver 4. If the projection of the interface passes in the middle of the photosensitive surface, then the intensity of the light falling on the photoreceiver from the right and left illuminator, is equal to. When the joint is shifted to the right, the illumination by the left illuminator increases, and to the left - by the right illumination. The signal from the photodetector enters

amplifier 5, and then synchronous detector 6, which extracts the amplitude of the modulated signal, taking into account its phase. In this case, the amplitude corresponding to the right and

the left light beam is converted to a voltage with opposite polarities. This voltage, proportional to the difference in amplitudes, is fed to comparator 9, issuing a command to actuator 10, which corrects the position of the welding head relative to the joint.

The use of the proposed method of tracking the joint in the process of arc

welding improves the accuracy and reliability of automatic joint tracking, and it can significantly reduce the requirements for deviations in the size and shape of standard parts.

Claims (1)

Claims The method of tracking the joint during the welding process, in which the joint is illuminated with modulated light, the luminous flux reflected from the joint is recorded. The received signal determines the direction of deflection of the welding torch relative to the joint, makes a correction of the position of the welding torch. , in order to improve the accuracy of tracking the joint by reducing the influence of interference from the light radiation of the welding arc, the joint zone is illuminated by two anti-phase modulated The light beams whose sources are located symmetrically on both sides of the photodetector, which is oriented to the illuminated junction zone, determine the direction of deviation from the junction by the difference in the magnitudes of the recorded signal in opposite phases of modulation. f6 Htk -