CN101655705B - A method and device for automatic tracking of thin plate butt weld seam based on intelligent camera - Google Patents

Abstract

The present invention is an intelligent camera-based thin-plate butt weld automatic tracking method and device. The intelligent camera is used to collect the image of the thin-plate butt weld, and a programmable controller is used to control the stepping motor to drive the offset of the welding torch to realize the automatic tracking of the welding torch. track. During the welding process, the welding torch and the smart camera move forward at a constant speed along the direction of the welding seam. The smart camera is installed in front of the welding torch, which filters the collected images and extracts the weld seam, and outputs the weld seam position to the programmable controller. According to the current position and expected position of the welding seam, the programmable controller controls the forward and reverse rotation of the stepping motor, so as to drive the welding torch to move left and right, so that the welding wire is at the desired welding seam position, so as to realize the welding operation of the welding torch accurately along the welding seam . The invention can improve the accuracy and reliability of welding seam tracking, and can realize automatic and accurate tracking of thin plate butt joint narrow welding seam, so as to meet the needs of thin plate butt joint automatic welding.

Description

A method and device for automatic tracking of thin plate butt weld seam based on intelligent camera

Technical field:

The invention relates to the technical field of thin plate welding, and relates to welding seam tracking in the field of robot vision control, in particular to an automatic tracking method and device for thin plate butt welding seam based on an intelligent camera.

technical background:

Traditional weld seam visual tracking uses structured light vision to measure welds, that is, project point or linear structured light onto the surface of the workpiece, and calculate the transverse profile of the weld through triangulation (see "Wu Lin, Chen Shanben, Intelligent Welding Technology , pp. 210-211, pp. 215-217, Beijing: National Defense Industry Press, 1999"; see "Xu De, Tan Min, Li Yuan, Robot Vision Measurement and Control, p. 133, Beijing: National Defense Industry Press Society, 2008"). This structured light weld seam measurement method is suitable for measuring weld seams with obvious transverse profile, such as V-groove welds, lap welds, etc. But for thin plate butt welds, because the weld is too narrow, it is difficult to distinguish the weld from the workpiece using structured light measurement. Therefore, the traditional structured light vision measurement is not suitable for the measurement of narrow butt welds of thin plates.

Traditional weld seam visual tracking uses a computer to form a control system, which is large in size and poor in reliability (see "Wu Lin, Chen Shanben, Intelligent Welding Technology, p. 226, Beijing: National Defense Industry Press, 1999").

One of the shortcomings of the current weld seam visual tracking technology is that it needs to obtain the transverse profile of the weld, and it is powerless for welds with inconspicuous transverse profile; the second defect is that the use of computer control results in a large volume and poor reliability of the control system .

Invention content:

The object of the present invention is to provide an intelligent camera-based automatic tracking method and device for butt welds of thin plates, which can overcome the deficiencies of the prior art and improve the accuracy and reliability of butt weld tracking for thin plates during welding.

For achieving the above object, technical solution of the present invention is:

A thin plate butt weld seam tracking method based on an intelligent camera, which comprises the steps of:

A) An intelligent camera is fixed on the side of the welding torch, and the intelligent camera is aimed at the intersection area of the welding wire and the butt weld of the thin plate;

B) Two-way communication connection between intelligent camera, touch screen, stepper motor driver and programmable controller;

C) Use the smart camera to collect the natural image of the weld, process the image of the weld, give the position of the weld, and send the data to the programmable controller;

D) Input parameters through the touch screen and display the tracking error of the weld;

E) Use the programmable controller to drive the stepper motor driver according to the data of the smart camera, control the stepper motor to drive the electric adjustment of the horizontal bracket on the horizontal axis to make the welding torch and welding wire move along the horizontal direction perpendicular to the butt weld of the thin plate, so as to Ensure the accuracy and reliability of welding.

In the method, the welding seam position is to use the welding seam straight line as a feature to calculate the welding seam position.

A device used in the method includes a fixed mount, an adjustment mechanism, a welding torch bracket, a welding torch, a stepping motor, and a power supply; wherein,

The fixed frame is installed on the welding machine, and the adjustment mechanism is fixedly connected to the lower end of the fixed frame; the adjustment mechanism includes three movement axes, among which, one manually adjusts the horizontal axis, one manually adjusts the vertical axis, and one electrically adjusts the horizontal axis; the two manual adjustment axes are opposite to each other. Orthogonal installation, with a hand wheel at one end of the two manual adjustment axes, which are used to manually adjust the height and horizontal position of the welding torch and camera respectively; the electric adjustment horizontal axis and the manual adjustment horizontal axis are arranged horizontally and parallel to each other , the output end of the stepping motor is fixedly connected to one end of the electric adjustment horizontal shaft, and a horizontal bracket is fixed on the side of the electric adjustment horizontal shaft, and the horizontal bracket and the electric adjustment horizontal shaft move together;

Two brackets protrude downward parallel to the lower side of the horizontal bracket, one welding torch bracket and one smart camera bracket;

There is a welding torch clip at the lower end of the welding torch bracket, and the welding torch is detachably fixed in the welding torch clip. The upper end of the welding torch is connected to the welding torch pipeline, and the lower end is connected to the welding wire; the lower end of the smart camera bracket is fixed with a smart camera, and the smart camera has a lighting source. At the same height as the welding gun, aim at the lower end area of the welding wire;

Electric adjustment of the horizontal axis is used to automatically adjust the horizontal position of the welding torch and the camera during the seam tracking process;

The stepping motor is electrically connected with the stepping motor driver;

The smart camera, stepper motor driver, and touch screen are electrically connected to the programmable controller and perform two-way communication;

The power supply supplies power to smart cameras, touch screens, programmable controllers, and stepper motor drivers.

In the described device, the illumination light source is an annular light source installed around the lens of the smart camera.

The outstanding feature of the present invention is that it uses an intelligent camera to collect and process weld images, and gives the position of the weld; it uses a programmable controller to control a stepping motor to drive the welding torch to move laterally; it uses a touch screen to input parameters and display tracking errors. Another outstanding feature of the present invention is to collect the natural image of the weld, and use the straight line of the weld as a feature to calculate the position of the weld.

The invention does not need to obtain the transverse profile of the weld, and can track the weld with an inconspicuous transverse profile; the invention uses an intelligent camera to collect and process weld images without using a traditional computer, which reduces the volume of the control system and improves the reliability.

The experiment proves that the invention can realize the tracking of the thin plate butt joint narrow weld seam, and can meet the needs of the thin plate butt joint automatic welding.

Description of drawings:

FIG. 1 is a structural schematic diagram of an automatic tracking device for thin plate butt welds based on an intelligent camera of the present invention.

Fig. 2 is a schematic diagram of the control system of the thin plate butt weld automatic tracking device based on the intelligent camera of the present invention.

Detailed ways:

The thin-plate butt weld automatic tracking device based on the intelligent camera of the present invention is composed of three adjustment shafts and some supports, see accompanying drawing 1 . Among them, the first axis is a manual adjustment horizontal axis 9, with a horizontal axis hand wheel 2, which is used to manually adjust the position of the welding torch 6 along the horizontal direction perpendicular to the welding seam, that is, to adjust the left and right positions of the welding torch 6 so that the welding wire 7 is in the welding position. Sew on. The second axis is a manual adjustment vertical axis 8 with a vertical axis hand wheel 1 for manually adjusting the position of the welding torch 6 along the vertical direction perpendicular to the welding seam, that is, adjusting the height of the welding torch 6 . The third axis is a horizontal electric adjustment horizontal axis 10 with a stepping motor 3 for automatically adjusting the position of the welding torch 6 along the horizontal direction perpendicular to the welding seam, that is, for automatic welding seam tracking. The manual adjustment vertical axis 8 is installed on the slide block of the manual adjustment horizontal axis 9, and the electric adjustment horizontal axis 10 is installed on the slide block of the manual adjustment vertical axis 8. A horizontal support 11 is housed on the slide block of the electric adjustment horizontal axis 10, and a welding torch support 12 and a camera support 13 are installed below. Along the advancing direction 16 , the camera support 13 is in front of the welding torch support 12 . The connecting rod at the end of the welding gun support 12 is connected with the welding gun clamp 5 for clamping the welding gun 6 . The lower end of the welding torch 6 is a welding wire 7 , and the upper end is a welding torch pipeline 4 . On the end face of the camera bracket 13, a smart camera 14 and an illumination source 15 are installed. Wherein, the illuminating light source 16 is installed around the lens of the smart camera 14 to illuminate the weldment within the field of view of the smart camera 14 . Horizontal support 11, welding torch support 12, camera support 13, welding torch clamp 5, welding torch 6, welding wire 7, welding torch pipeline 4, intelligent camera 14 and illumination source 15, move together with the slide block of electric adjustment horizontal axis 10. There is a fixed positional relationship between the welding torch 6 and the smart camera 14 .

The seam tracking device of the present invention is composed of an intelligent camera 14, a touch screen 18, a programmable controller 19, a stepper motor driver 20, a stepper motor 3, a switching power supply 17 and the above-mentioned tracking adjustment mechanism, see accompanying drawing 2 . Wherein, the smart camera 14 is connected with the programmable controller 19 through a serial port, and the touch screen 18 is connected with the programmable controller 19 through another serial port. The touch screen 18 is used to input parameters and display tracking error. The programmable controller 19 outputs two signals to the stepping motor driver 20, which are respectively a motion pulse signal and a motion direction signal. The drive output of the stepper motor driver 20 is directly connected to the input signal end of the stepper motor 3 by wires. The switching power supply 17 is used to supply power to the smart camera 14 , the touch screen 18 , the programmable controller 19 and the stepper motor driver 20 .

The present invention adopts the intelligent camera 14 to filter the collected images and extract the weld seam, and output the weld seam position to the programmable controller 19 . The programmable controller 19 controls the positive and negative rotation of the stepping motor 3 through the stepping motor driver 20 according to the current position and the desired position of the welding seam, thereby driving the welding torch 6 to move left and right, so that the welding wire 7 is at the desired welding seam position, Thereby the welding operation of the welding torch 6 along the weld seam is realized accurately.

Example

See Figure 1. In the embodiment, as shown in FIG. 1 , a seam tracking mechanism is manufactured. See Figure 2. The control system hardware of the seam tracking device is composed of a programmable controller 19 , a touch screen 18 , an intelligent camera 14 , a stepper motor driver 20 , a stepper motor 3 , and a switching power supply 17 . In the embodiment, the programmable controller 19 selects Japanese OMRON CP1H-X40DT-D, the touch screen 18 selects the MPT5-MG00B touch screen, the intelligent camera 14 selects the VC4068 intelligent camera made in Germany, and the stepper motor 3 selects Hollysys 56BYG250D For the two-phase hybrid stepping motor, the stepping motor driver 20 selects Hollysys' two-phase hybrid stepping motor subdivision driver SH-20403. There are two serial ports on the programmable controller 19, one serial port is used for connecting with the touch screen 18, and the other serial port is used for connecting with the smart camera 14. The high-speed pulse output terminal and the motion direction terminal of the programmable controller 19 are connected to the stepper motor driver 20 . The drive output of the stepper motor driver 20 is directly connected to the input signal end of the stepper motor 3 by wires.

The actual application of the embodiment proves that the present invention is easy to implement, can realize automatic tracking of thin plate butt joint narrow welds, and can meet the needs of thin plate butt joint automatic welding.

Claims (3)

1. The automatic sheet butt weld tracking method based on the intelligent camera is characterized by comprising the following steps of:

A) fixedly mounting an intelligent camera in front of a welding gun, and aligning the intelligent camera with a welding wire and sheet butt welding joint area;

B) the intelligent camera, the touch screen and the stepping motor driver are respectively in two-way communication connection with the programmable controller;

C) collecting a natural image of a welding seam by using an intelligent camera, processing the welding seam image, giving a welding seam position, and sending data to a programmable controller;

D) inputting parameters through a touch screen and displaying the tracking error of the welding line;

E) driving a stepping motor driver by using a programmable controller according to the data of the intelligent camera, and controlling a stepping motor to drive a transverse bracket on a transverse shaft to be adjusted in a power-driven manner so as to enable a welding gun and a welding wire to move along the horizontal direction vertical to the butt welding seam of the thin plate, thereby ensuring the accuracy and reliability of welding;

and the welding seam position is calculated by taking the welding seam straight line as a characteristic.

2. An apparatus for use in the method of claim 1, comprising a holder, an adjustment mechanism, a torch support, a torch, a stepper motor, a power source; it is characterized in that the preparation method is characterized in that,

the fixed frame is arranged on the welding machine, and the adjusting mechanism is fixedly connected with the lower end of the fixed frame; the adjusting mechanism comprises three moving shafts, wherein a manual adjusting transverse shaft, a manual adjusting vertical shaft and an electric adjusting transverse shaft are arranged in the adjusting mechanism; the two manual adjusting shafts are installed in a relative orthogonal mode, hand wheels are arranged at one ends of the two manual adjusting shafts respectively, and the two manual adjusting shafts are used for manually adjusting the height and the horizontal position of the welding gun and the camera respectively; the electric adjusting transverse shaft and the manual adjusting transverse shaft are horizontally arranged in parallel, the output end of the stepping motor is fixedly connected with one end of the electric adjusting transverse shaft, a transverse bracket is fixedly arranged on the electric adjusting transverse shaft in the lateral direction, and the transverse bracket and the electric adjusting transverse shaft move together;

the lower side of the transverse bracket extends downwards in parallel to form two brackets, namely a welding gun bracket and an intelligent camera bracket;

the lower end of the welding gun bracket is provided with a welding gun clamp, a welding gun is detachably and fixedly connected in the welding gun clamp, the upper end of the welding gun is connected with a welding gun pipeline, and the lower end of the welding gun is connected with a welding wire; the lower end of the intelligent camera support is fixedly connected with an intelligent camera, the intelligent camera is provided with an illumination light source, and the intelligent camera is positioned on the side surface of the welding gun, has the same height with the welding gun and is aligned with the lower end area of the welding wire;

the electric adjusting transverse shaft is used for automatically adjusting the horizontal positions of the welding gun and the camera in the welding seam tracking process;

the stepping motor is electrically connected with the stepping motor driver;

the intelligent camera, the stepping motor driver and the touch screen are respectively and electrically connected with the programmable controller and carry out two-way communication;

the power supply supplies power to the intelligent camera, the touch screen, the programmable controller and the stepping motor driver.

3. The apparatus of claim 2, wherein the illumination source is a ring light source mounted around a lens of the smart camera.

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