CN108788394B - Laser scanning welding seam tracking device and tracking method thereof - Google Patents
Laser scanning welding seam tracking device and tracking method thereof Download PDFInfo
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- CN108788394B CN108788394B CN201810526859.4A CN201810526859A CN108788394B CN 108788394 B CN108788394 B CN 108788394B CN 201810526859 A CN201810526859 A CN 201810526859A CN 108788394 B CN108788394 B CN 108788394B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K9/00—Arc welding or cutting
- B23K9/12—Automatic feeding or moving of electrodes or work for spot or seam welding or cutting
- B23K9/127—Means for tracking lines during arc welding or cutting
- B23K9/1272—Geometry oriented, e.g. beam optical trading
- B23K9/1274—Using non-contact, optical means, e.g. laser means
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Abstract
The invention belongs to the technical field of welding, and particularly relates to a laser scanning weld seam tracking device which comprises a supporting mechanism and a laser tracking mechanism, wherein the laser tracking mechanism comprises a laser displacement sensor, a stepping motor, a connecting plate and a mounting plate, the connecting plate is fixedly arranged on the supporting mechanism, the stepping motor is fixedly arranged on the connecting plate, one end of the mounting plate is fixedly connected with an output shaft of the stepping motor, the other end of the mounting plate is fixedly connected with the laser displacement sensor, the mounting plate is also fixedly provided with a positioning sensor, the laser displacement sensor faces towards a weld seam, and the stepping motor drives the laser displacement sensor to reciprocate in a square arc above the weld seam. Has the advantages that: the laser scanning welding seam tracking device has strong adaptability to welding environment, simple structure, ingenious design, convenient maintenance and lower cost; the tracking method of the laser scanning welding seam tracking device is simple and convenient to operate, rapid in calculation and high in practical application value.
Description
Technical Field
The invention belongs to the technical field of welding, and particularly relates to a laser scanning welding seam tracking device and a tracking method thereof.
Background
In the automatic welding process, if the relative position of the welding gun head and the welding seam generates deviation, defects such as poor forming and incomplete penetration can be caused. In the welding manufacturing process, the relative position error between the welding gun and the welding seam needs to be detected and corrected due to the severe environment during welding, the assembly error of a weldment, the welding stress and the change of the position and the size of the welding seam caused by welding deformation, so that the adoption of the welding seam tracking technology is particularly important. In order to overcome the influence of uncertain factors such as the size and the section inconsistency of a welding seam on the welding quality and improve the reliability of automatic servo welding, an automatic servo mechanism such as a robot is required to adjust the position of a welding gun on line in real time, so that the welding gun is ensured to be centered on the welding seam center, and the welding seam forming quality is ensured.
The contact type welding seam tracking sensor is free from arc interference, simple in structure, direct in operation, convenient to maintain and low in cost, and is the most used welding seam tracking method at present. However, the mechanical contact sensor has high requirements on the processing of the groove, and any damage and roughness of the surface of the tracking groove can influence the tracking stability and the tracking precision; the probe is always in contact with the groove, is large in abrasion and easy to deform and needs to be replaced frequently; in addition, when the large-groove welding seam adopts multilayer multi-pass welding, the tracking can be only carried out during the first-layer backing welding, and the rest welding seams can not be used as the power.
Disclosure of Invention
The invention provides a laser scanning welding seam tracking device and a tracking method thereof, aiming at solving the problems that the widely applied contact welding seam tracking sensor in the prior art has higher requirements on the processing of a groove, the probe of the contact welding seam tracking sensor is always in contact with the groove, has larger abrasion and is easy to deform and needs to be replaced frequently.
In order to solve the technical problems, the technical scheme adopted by the invention is that the laser scanning weld seam tracking device comprises a supporting mechanism and a laser tracking mechanism, wherein the laser tracking mechanism comprises a laser displacement sensor, a stepping motor, a connecting plate and a mounting plate, the connecting plate is fixedly arranged on the supporting mechanism, the stepping motor is fixedly arranged on the connecting plate, one end of the mounting plate is fixedly connected with an output shaft of the stepping motor, the other end of the mounting plate is fixedly connected with the laser displacement sensor, the mounting plate is also fixedly provided with a positioning sensor, the laser displacement sensor faces towards a weld seam, and the stepping motor drives the laser displacement sensor to reciprocate on the square arc above the weld seam.
Further, the supporting mechanism comprises an upper supporting structure and a lower supporting structure, a buffer spring is arranged between the upper supporting structure and the lower supporting structure, the bottom surface of the lower supporting structure is fixedly provided with a roller, and the connecting plate is fixedly arranged on the lower supporting structure. The roller of the welding seam tracking device is always in contact with a welding workpiece to ensure high stability, reduce friction with the surface of the welding workpiece and improve the measurement precision of the welding seam tracking device; the buffer spring can effectively protect the roller from being crushed, and the service life of the welding seam tracking device is prolonged.
The tracking method of the laser scanning welding seam tracking device comprises the following steps: the laser displacement sensor transversely scans the welding seam in a reciprocating manner along the arc track, acquires depth information of the arc path corresponding to the arc track of the laser displacement sensor in the welding seam, and corrects the depth information of the arc path into depth information of a linear path;
the correction processing procedure is as follows: connecting a certain arc path with two intersection points of the boundary of the upper end surface of the welding seam by a straight line, wherein the orthographic projection of the straight line in the welding seam is a straight line path; obtaining coordinates of two intersection points, center coordinates of a straight line path and width information of the straight line path by using a positioning sensor, respectively dividing the arc path and a previous arc path into N equal parts, respectively connecting each equal division point corresponding to the two arc paths to obtain N equal division lines, knowing that the depth of a certain equal division point of the arc path is a, the depth of the equal division point corresponding to the previous arc path is b, the depth of the point to be solved at the intersection of the equal division lines and the straight line path is c, the distances from the point to be solved to the equal division points of the arc path and the previous arc path are s1 and s2 respectively, and then the depth of the point to be solved is: c ═ a × s2+ b × s1)/(s1+ s2), the cross-sectional shape and area of the weld passing through the straight path can be obtained by fitting the depth of each point to be found;
after correction, the welding manipulator drives the welding gun to adjust the posture, the position and the speed according to the shape and the area of the cross section, so that the welding gun is always positioned at the center of the welding seam until the whole welding seam is welded.
Furthermore, before the laser displacement sensor scans the welding seam in a reciprocating manner along an arc track, a mechanical zero point set by the positioning sensor of the welding manipulator is manually adjusted, the welding manipulator drives the laser displacement sensor to move above the welding seam, the laser displacement sensor is perpendicular to the welding seam, and then the rotation angle of the stepping motor is adjusted to be positioned at the original point position of the positioning sensor, so that the original point position is the left starting point of the transverse scanning welding seam.
Further, before the laser displacement sensor transversely scans the welding seam in a reciprocating manner along the arc track, the stroke of the stepping motor for driving the laser displacement sensor to transversely scan the welding seam in a reciprocating manner along the arc track is set, and the stroke is larger than the maximum welding seam width.
Has the advantages that: the stepping motor drives the laser displacement sensor to transversely scan the depth information of each point of a welding seam in a reciprocating manner along an arc track, the depth information of a straight path is calculated by interpolation and correction of the depth information of front and rear arc paths by means of the positioning sensor, the depth information of the straight path is converted into the coordinate, the width and the depth information of the center position of the welding seam, the welding manipulator is adjusted in real time to drive the welding gun to adjust the posture, the position and the speed, and the welding seam tracking is realized; the tracking method of the laser scanning welding seam tracking device is simple and convenient to operate, rapid in calculation and high in practical application value.
Drawings
FIG. 1 is a schematic perspective view of the assembly of a laser scanning seam tracking device and a welding robot according to the present invention;
FIG. 2 is an enlarged partial schematic view of A of FIG. 1;
FIG. 3 is a schematic perspective view of a laser scanning seam tracking device according to the present invention;
FIG. 4 is a schematic diagram of the tracking method of the laser scanning seam tracking apparatus of the present invention;
in the figure, 1, a support mechanism, 11, an upper support structure, 12, a lower support structure, 13, a buffer spring, 14, a roller, 2, a laser tracking mechanism, 21, a laser displacement sensor, 22, a positioning sensor, 23, a stepping motor, 24, a connecting plate, 25, a mounting plate, 31, an arc path, 32, a linear path, 4, a welding manipulator, 5, a welding seam, a certain dividing point depth of the arc path, b, a previous arc path corresponding to a dividing point depth, c, a point depth to be solved, s1, a linear distance from the point to be solved to a dividing point of the arc path, s2, and a linear distance from the point to be solved to a dividing point of the previous arc path.
Detailed Description
Examples
As shown in fig. 1-4, a laser scanning welding seam tracking device, this welding seam tracking device and welder set up side by side on welding manipulator 4, including supporting mechanism 1 and laser tracking mechanism 2, laser tracking mechanism 2 includes laser displacement sensor 21, step motor 23, connecting plate 24 and mounting panel 25, connecting plate 24 is fixed to be set up on supporting mechanism 1, step motor 23 is fixed to be set up on connecting plate 24, the one end of mounting panel 25 and step motor 23's output shaft fixed connection, its other end and laser displacement sensor 21 fixed connection, still fixed being provided with positioning sensor 22 on the mounting panel 25, laser displacement sensor 21 is towards welding seam 5, step motor 23 drives laser displacement sensor 21 at welding seam 5 top circular arc reciprocating motion. In order to ensure that the supporting mechanism 1 is stably and reliably supported, the supporting mechanism 1 comprises an upper supporting structure 11 and a lower supporting structure 12, a buffer spring 13 is arranged between the upper supporting structure 11 and the lower supporting structure 12, a roller 14 is fixedly arranged on the bottom surface of the lower supporting structure 12, a connecting plate 24 is fixedly arranged on the lower supporting structure 12, the roller 14 is always in contact with a welding workpiece to ensure the height stability, the friction with the surface of the welding workpiece is reduced, and the measurement precision of the welding seam tracking device is improved; the buffer spring 13 can effectively protect the roller 14 from being crushed, and the service life of the welding seam tracking device is prolonged.
The tracking method of the laser scanning welding seam tracking device comprises the following steps:
firstly, manually adjusting the welding manipulator 4 to return to a mechanical zero point set by the positioning sensor 22, then driving the laser displacement sensor 21 to move above the welding seam 5 by the welding manipulator 4, enabling the laser displacement sensor 21 to be perpendicular to the welding seam 5, setting a stroke of driving the laser displacement sensor 21 to transversely scan the welding seam 5 in a reciprocating manner along an arc track by the stepping motor 23, wherein the stroke is larger than the width of the maximum welding seam 5, then adjusting the rotation angle of the stepping motor 23 to be positioned at an original point position of the positioning sensor 22, and enabling the original point position to be a left starting point of the transverse scanning welding seam 5.
After welding processing is started, the welding manipulator 4 drives the laser tracking mechanism 2 to move longitudinally along the welding seam 5, meanwhile, the stepping motor 23 is started, the stepping motor drives the laser displacement sensor 21 to scan the welding seam 5 transversely in a reciprocating manner along an arc track, depth information of an arc path 31 corresponding to the arc track of the laser displacement sensor 21 in the welding seam 5 is collected, orthographic projection of the arc track of the laser displacement sensor 21 in the welding seam 5 is the arc path 31, and then the depth information of the arc path 31 is corrected into depth information of a straight path 32;
the correction processing procedure is as follows: connecting a certain arc path 31 with two intersection points of the boundary of the upper end surface of the welding seam 5 by a straight line, wherein the orthographic projection of the straight line in the welding seam 5 is a straight line path 32; obtaining coordinates of two intersection points, center coordinates of a straight path 32 and width information of the straight path 32 by using a positioning sensor 22, thereby obtaining coordinates of a central position of a welding seam 5 at the straight path 32 and the width information of the straight path 32, further dividing the arc path 31 and a previous arc path 31 into N equal parts, wherein the arc path 31 and the previous arc path 31 are parallel along a longitudinal direction of the welding seam 5, and respectively connecting each equal division point corresponding to the two arc paths 31 to obtain N equal division lines, knowing that a certain equal division point depth of the arc path 31 is a, a equal division point depth corresponding to the previous arc path 31 is b, a depth of a point to be solved at the intersection of the equal division lines and the straight path 32 is c, linear distances from the point to be solved to equal division points of the arc path 31 and the previous arc path 31 are s1 and s2, respectively, and adopting a linear interpolation method, the depth of the point to be solved is: c ═ a × s2+ b × s1)/(s1+ s2), the cross-sectional shape and area of the weld 5 passing through the straight path 32 can be fitted by the depth of each point to be found;
after the correction processing, the position information of the positioning sensor 22 and the position information are sent to a servo control processor of the welding manipulator 4, and the welding manipulator 4 drives a welding gun to adjust the posture, the position and the speed through the center position coordinate, the width information, the section shape and the area of the welding seam 5, so that the welding gun is always positioned at the center position of the welding seam 5 until the welding of the whole welding seam 5 is completed.
Claims (3)
1. A tracking method of a laser scanning welding seam tracking device is characterized in that: the device comprises a supporting mechanism (1) and a laser tracking mechanism (2), wherein the laser tracking mechanism (2) comprises a laser displacement sensor (21), a stepping motor (23), a connecting plate (24) and a mounting plate (25), the connecting plate (24) is fixedly arranged on the supporting mechanism (1), the stepping motor (23) is fixedly arranged on the connecting plate (24), one end of the mounting plate (25) is fixedly connected with an output shaft of the stepping motor (23), the other end of the mounting plate is fixedly connected with the laser displacement sensor (21), a positioning sensor (22) is further fixedly arranged on the mounting plate (25), the laser displacement sensor (21) faces towards a welding seam (5), and the stepping motor (23) drives the laser displacement sensor (21) to do circular arc reciprocating movement above the welding seam (5);
the laser displacement sensor (21) transversely scans the welding seam (5) in a reciprocating manner along the arc track, the depth information of the arc path (31) corresponding to the arc track of the laser displacement sensor (21) in the welding seam (5) is collected, and then the depth information of the arc path (31) is corrected into the depth information of the straight path (32);
the correction processing procedure is as follows: a certain arc path (31) is connected with two intersection points of the boundary of the upper end surface of the welding seam (5) in a straight line, and the orthographic projection of the straight line in the welding seam (5) is a straight line path (32); obtaining coordinates of two intersection points, center coordinates of a straight line path (32) and width information of the straight line path (32) by means of a positioning sensor (22), dividing the arc path (31) and a previous arc path (31) into N equal parts respectively, connecting each equal division point corresponding to the two arc paths (31) respectively to obtain N equal division lines, knowing that the depth of a certain equal division point of the arc path (31) is a, the depth of the equal division point corresponding to the previous arc path (31) is b, the depth of the point to be solved at the intersection of the equal division lines and the straight line path (32) is c, the distances from the point to be solved to the equal division points of the arc path (31) and the previous arc path (31) are s1 and s2 respectively, and then the depth of the point to be solved is: c ═ a × s2+ b × s1)/(s1+ s2), the cross-sectional shape and area of the weld (5) at the position passing through the straight path (32) can be obtained by fitting the depth of each point to be found;
after correction, the welding manipulator (4) drives the welding gun to adjust the posture, the position and the speed according to the shape and the area of the section, so that the welding gun is always positioned at the central position of the welding seam (5) until the welding of the whole welding seam (5) is finished.
2. The tracking method of the laser scanning seam tracking apparatus according to claim 1, characterized in that: before the laser displacement sensor (21) transversely scans the welding seam (5) in a reciprocating manner along an arc track, the welding manipulator (4) is manually adjusted to return to a mechanical zero point set by the positioning sensor (22), the welding manipulator (4) drives the laser displacement sensor (21) to move above the welding seam (5), the laser displacement sensor (21) is perpendicular to the welding seam (5), and then the rotating angle of the stepping motor (23) is adjusted to be positioned at the original point position of the positioning sensor (22), so that the original point position is the left starting point of the transverse scanning welding seam (5).
3. The tracking method of the laser scanning seam tracking apparatus according to claim 2, characterized in that: before the laser displacement sensor (21) transversely scans the welding seam (5) in a reciprocating manner along an arc track, the stroke of driving the laser displacement sensor (21) to transversely scan the welding seam (5) in a reciprocating manner along the arc track by the stepping motor (23) is set, and the stroke is larger than the width of the maximum welding seam (5).
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| CN110102856A (en) * | 2019-05-28 | 2019-08-09 | 广州工顺焊接科技有限公司 | A kind of method of the 3D scanning weld seam of laser scanning weld seam equipment |
| CN111730180A (en) * | 2020-06-10 | 2020-10-02 | 北京工业大学 | Dynamic assembling and adjusting method for thin plate during welding and pressing |
| CN111745267A (en) * | 2020-08-14 | 2020-10-09 | 湘潭大学 | System and method for tracking groove weld in real time based on laser displacement sensor |
| CN115673630B (en) * | 2022-11-17 | 2023-10-20 | 广州华夏职业学院 | Nonstandard refrigeration house door welding method, system, terminal and medium based on 3D tracking |
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