A laser-assisted teaching programming device for robot welding
By using laser ranging sensors and teaching controllers in robot welding devices, combined with TCP calibration device and adjustable positioning connection mechanism, the problem of low dry elongation and pointing position accuracy in traditional methods is solved, and high accuracy is achieved. The rapid welding trajectory determination improves the teaching programming efficiency.
Patent Information
- Application Number
- CN202010846623.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2020-08-21
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2040-08-21
AI Technical Summary
Traditional methods are used to determine the dry elongation length of the robot welding and the pointing position of the welding wire, and there are measurement errors and deformation problems, which lead to repeated corrections, which is time-consuming and labor-intensive.
Using laser ranging sensor and teaching controller, the laser ranging sensor is installed at the front end of the welding gun, the length of the welding wire is measured by a laser beam, and the pointing position of the welding wire is determined by the laser point on the workpiece, combining the TCP calibration device and adjustable positioning connection mechanism to improve measurement accuracy and speed.
It significantly improves measurement accuracy and speed, reduces deviations in dry elongation and directional position, improves teaching programming efficiency, avoids inaccuracy caused by contact deformation of welding wire, and measures errors can reach ten micron level.
Smart Images
Figure CN112077487B_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a laser-assisted teaching programming device, which can assist an operator to quickly and accurately determine a welding trajectory when compiling a robot welding program, and belongs to the technical field of welding. Background Art
[0002] Robots are increasingly widely used in the field of automotive parts welding due to their high efficiency and high stability. Before welding production, as long as the teaching programming is completed and the motion trajectory is determined, the robot will accurately repeat these welding actions during production to ensure high-quality welding. The welding dry extension length and the wire pointing position are very important parameters in the robot welding motion trajectory. The welding dry extension length refers to the length of the welding wire from the conductive nozzle to the workpiece, and its size affects the penetration and appearance of the weld. The wire pointing position refers to the position where the end of the welding wire contacts the workpiece, which determines whether there is sufficient penetration on both sides of the welding joint. Accurately determining the welding dry extension length and the wire pointing position is of great significance to ensure welding quality. The traditional method for determining the robot welding dry extension length and the wire pointing position is: use a steel ruler to measure, and use the wire cutter and wire feeder to control the length of the welding wire extending from the conductive nozzle to reach the dry extension length required by the process, and then control the robot to drive the welding gun to move the end of the welding wire to the welding wire pointing position required by the process, at which time the end of the welding wire just contacts the workpiece. The disadvantage of this method is that the control accuracy is low. The measurement error of the steel ruler, the bending deformation of the welding wire, the elastic expansion and contraction of the welding wire during the movement of the robot, the shaking of the welding wire in the conductive nozzle, the contact deformation of the welding wire and the workpiece, and the observation error of the human eye will cause the actual extension length and pointing position to deviate. Generally, this deviation is more than 0.2 mm. At the same time, because of the above-mentioned influencing factors, the extension length and pointing position need to be repeatedly corrected, which is time-consuming and labor-intensive. Summary of the invention
[0003] The purpose of the present invention is to address the shortcomings of the prior art and provide a laser-assisted teaching programming device for robot welding to accurately determine the welding dry extension length and the welding wire pointing position, thereby improving the teaching programming efficiency.
[0004] The problem described in the present invention is solved by the following technical solution:
[0005] A laser-assisted teaching programming device for robot welding includes a laser ranging sensor, a teaching controller and a power supply. The laser ranging sensor is installed at the front end of a welding gun welded on the robot. The irradiation direction of a visible laser beam emitted by the laser ranging sensor after power is turned on is the axial direction of a welding wire through hole in a conductive nozzle of the welding gun. The teaching controller is connected to the power supply and the laser ranging sensor via a cable.
[0006] The above-mentioned laser-assisted teaching programming device for robot welding, the laser ranging sensor is connected to the welding gun through an adjustable positioning connection mechanism, the adjustable positioning connection mechanism includes a sensor protection sleeve, a positioning sleeve, a locking nut and three set screws, the positioning sleeve has the same appearance as the welding gun nozzle, and the rear end of the positioning sleeve is connected to the front end of the welding gun through a thread; the sensor protection sleeve is coaxially assembled in the positioning sleeve, the front end outer surface of the sensor protection sleeve is a conical surface matching the conical hole at the front end of the positioning sleeve, the rear end is clearance-matched with the positioning sleeve, and the three set screws are evenly arranged around the axis of the positioning sleeve, each set screw is screwed into a radial threaded hole on the side wall of the positioning sleeve and pressed against the outer wall of the sensor protection sleeve; the laser ranging sensor is assembled to the front end of the sensor protection sleeve through its own external thread and is locked by the locking nut.
[0007] The above-mentioned laser-assisted teaching programming device for robot welding also includes a TCP calibration device, which includes a TCP calibration pin, a TCP calibration block and a rigid mounting seat. The TCP calibration block is fixed near the robot through the rigid mounting seat and its relative position with the robot remains unchanged. A cross line is engraved on the upper plane of the TCP calibration block. The TCP calibration pin is coaxial with the conductive nozzle of the welding gun. The rear end of the TCP calibration pin is connected to the welding gun through an external thread of the same specification as the conductive nozzle, and the front end is conical, and the tip of the cone coincides with the end point of the welding wire of the theoretical welding dry extension length.
[0008] The laser-assisted teaching programming device for robot welding, wherein the teaching controller and the power supply are fixed on the arm of the welding robot via a power supply mounting plate.
[0009] In the above-mentioned laser-assisted teaching and programming device for robot welding, the line width of the cross-intersection line on the plane of the TCP calibration block is 0.5 mm, and the line depth is less than 0.1 mm.
[0010] In the laser-assisted teaching programming device for robot welding, the rear end of the positioning sleeve is provided with an opening, and the cable of the signal output end of the laser ranging sensor passes through the opening.
[0011] In the above-mentioned laser-assisted teaching programming device for robot welding, the outer diameter of the rear end of the sensor protection sleeve is 0.5 mm smaller than the inner diameter of the positioning sleeve.
[0012] In the above-mentioned laser-assisted teaching programming device for robot welding, the output voltage of the power supply is 24V.
[0013] The present invention uses a laser distance measuring sensor to measure the welding dry extension length and determines the wire pointing position through the laser light spot on the workpiece, which can avoid the inaccuracy caused by the deformation of the welding wire contacting the workpiece in the existing method, and greatly improves the measurement accuracy and measurement speed. The device can assist the operator to quickly and accurately determine the welding trajectory, thereby improving the teaching programming efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention will be further described below in conjunction with the accompanying drawings.
[0015] Figure 1 This is a schematic diagram of a typical robot and welding gun;
[0016] Figure 2 It is a schematic diagram of the welding wire extension length and pointing position during the existing method of teaching programming;
[0017] Figure 3 It is a schematic diagram of the structure of the present invention;
[0018] Figure 4 yes Figure 3 A partial enlarged view of
[0019] Figure 5 This is a schematic diagram of the robot TCP calibration;
[0020] Figure 6 It is a schematic diagram of the welding wire extension length and pointing position during the auxiliary teaching programming of the present invention.
[0021] The numbers in the figure are as follows: 1. Robot, 2. Welding gun, 2-1. Welding gun body, 2-2. Nozzle, 2-3. Conductive nozzle, 3. Welding wire, 4. Workpiece, 5. Power supply, 6. Teaching controller, 7. Power supply mounting plate, 8. TCP calibration pin, 9. TCP calibration block, 10. Rigid mounting seat, 11. Set screw, 12. Locking nut, 13. Cable, 14. Laser ranging sensor, 15. Sensor protection cover, 16. Positioning sleeve, P, welding wire pointing position, d, welding dry extension length. DETAILED DESCRIPTION
[0022] The invention provides a laser-assisted teaching programming device, which can assist an operator to quickly and accurately determine a welding trajectory when compiling a robot welding program.
[0023] See also Figure 3 and Figure 4The present invention includes a laser distance measuring sensor 14, a sensor protection sleeve 15, a positioning sleeve 16, a cable 13, a 24V power supply 5, a teaching controller 6, a power supply mounting plate 7, a TCP calibration pin 8, a TCP calibration block 9, and a rigid mounting seat 10. The laser distance measuring sensor 14 is assembled to the sensor protection sleeve 15 through its own external thread and is locked by a locking nut 12; the sensor protection sleeve 15 is assembled to the positioning sleeve 16, and its front end is designed to be conical, with the same taper as the cone hole of the positioning sleeve 16, and the outer diameter of the rear end is designed to be 0.5mm smaller than the inner diameter of the positioning sleeve 16; the positioning sleeve 16 is provided with 3 evenly arranged set screws 11 to fix and adjust the sensor protection sleeve 15; the shape and rear end external thread of the positioning sleeve 16 are the same as the specifications of the welding gun nozzle, and can be installed on the front end of the welding gun through the rear end external thread; the rear end of the positioning sleeve 16 is provided with an opening for the cable 13 to pass through; the teaching controller The device 6 and the 24V power supply 5 are installed on the power supply mounting plate 7 by screws; the power supply mounting plate 7 is installed on the robot arm by screws; the teaching controller 6 is connected to the 24V power supply 5 and the laser ranging sensor 14 respectively through the cable 13; the TCP calibration block 9 is engraved with vertical cross lines on the plane, the line width is 0.5mm, and the line depth is less than 0.1mm; the TCP calibration block 9 is fixed to the rigid mounting seat 10 near the robot by screws and cylindrical pins, and the relative position with the robot remains unchanged; the rear end external thread of the TCP calibration pin 8 is the same as the specification of the welding gun conductive nozzle, and the front end is designed to be conical, and the tip of the cone coincides with the end point of the welding wire of the theoretical dry extension length.
[0024] After the laser distance measuring sensor 14 is powered on, it emits a laser, which is irradiated onto the workpiece 4 to form a tiny laser light spot that can be observed by the human eye, and the distance between the light spot and the welding gun can be displayed on the electronic screen of the teaching controller 6.
[0025] Before using the present invention, the position of the laser ranging sensor 14 needs to be calibrated so that its irradiated light spot coincides with the robot TCP point. The specific method is as follows: Figure 2 , Figure 3 , Figure 4 and Figure 5 First, remove the nozzle and conductive nozzle from the robot welding gun, then tighten the TCP calibration pin 8 on the welding gun, move the robot so that the tip of the TCP calibration pin 8 is aligned with the center of the cross line of the TCP calibration block 9, repeat 3 different postures and record the robot position points in the program, and then unscrew the TCP calibration pin 8; see Figure 5Tighten the positioning sleeve 16 equipped with the laser ranging sensor 14 and the sensor protection cover 15 on the welding gun, move the robot to the first position point just recorded, adjust the three set screws 11 on the positioning sleeve 16, so that the light spot of the laser ranging sensor 14 is irradiated on the center of the cross line, and then perform zero operation on the teaching controller 6. At this time, the distance displayed by the teaching controller 3 is 0, and then continue to move the robot to the other two points respectively, check the light spot position and the distance value displayed by the teaching controller 6, if there is a deviation, adjust the position of the laser ranging sensor 14 until the deviations of the three positions are within a small range, and the calibration work is completed.
[0026] See also Figure 6 When the present invention is used, the operator controls the robot to use a welding gun with a laser ranging sensor 14 to teach the workpiece 4, determines the welding wire pointing position through the laser light spot, and determines the welding wire extension length through the value (0 or close to 0) displayed by the teaching controller 6. After the teaching programming is completed, the auxiliary device is disassembled, the conductive nozzle and the nozzle of the original welding gun are installed, and trial welding production can be carried out.
[0027] The advantages of the present invention are as follows: 1. During the teaching programming process, the laser ranging sensor and the workpiece remain in a non-contact state, avoiding the inaccuracy caused by the deformation of the welding wire contacting the workpiece in the existing method. 2. The dry extension length is measured using a laser ranging sensor, and the measurement error can reach the ten-micron level, with high accuracy and high speed, and the dry extension length value of any welding position can be displayed in real time. 3. The pointing position can be directly observed through the laser light spot on the workpiece, and the operator can make accurate and convenient judgments. 4. The design position of the laser ranging sensor is coaxial with the conductive nozzle, and the light spot has good accessibility. As long as the welding gun can weld, the light spot can be observed. 5. It is easy to disassemble and use, does not require external water, electricity and gas, and is not restricted by the production environment.
Claims
1. A laser-assisted teaching programming method for robot welding, characterized in that: The method utilizes a laser-assisted teaching programming device, which comprises a laser distance sensor (14), a teaching controller (6) and a power source (5). The laser distance sensor (14) is installed at the front end of a welding gun (2) of a welding robot. The irradiation direction of a visible laser beam emitted by the laser distance sensor (14) after being powered on is the axial direction of a welding wire through hole in a welding gun conductive nozzle (2-3). The teaching controller (6) is connected to the power source (5) and the laser distance sensor (14) via a cable (13). The laser distance measuring sensor (14) is connected to the welding gun via an adjustable positioning connection mechanism, wherein the adjustable positioning connection mechanism comprises a sensor protection sleeve (15), a positioning sleeve (16), a locking nut (12) and three set screws (11), wherein the positioning sleeve (16) has the same shape as the welding gun nozzle (2-2), and the rear end of the positioning sleeve (16) is connected to the front end of the welding gun (2) via a thread; the sensor protection sleeve (15) is coaxially assembled in the positioning sleeve (16), and the sensor protection sleeve (15) is coaxially assembled in the positioning sleeve (16). The front end outer surface of the positioning sleeve (16) is a conical surface matching the conical hole at the front end of the positioning sleeve (16), and the rear end is clearance-matched with the positioning sleeve (16). Three set screws (11) are evenly arranged around the axis of the positioning sleeve (16). Each set screw (11) is screwed into a radial threaded hole on the side wall of the positioning sleeve (16) and pressed against the outer wall of the sensor protective sleeve (15). The laser distance sensor (14) is assembled on the front end of the sensor protective sleeve (15) through its own external thread and is locked by a locking nut (12). The laser-assisted teaching programming device also includes a TCP calibration device, which includes a TCP calibration pin (8), a TCP calibration block (9) and a rigid mounting seat (10). The TCP calibration block (9) is fixed near the robot through the rigid mounting seat (10) and its relative position with the robot remains unchanged. A cross line is engraved on the upper plane of the TCP calibration block (9). The TCP calibration pin (8) is coaxial with the conductive nozzle (2-3) of the welding gun. The rear end of the TCP calibration pin (8) is connected to the welding gun through an external thread of the same specification as the conductive nozzle (2-3). The front end is conical, and the tip of the cone coincides with the end point of the welding wire of the theoretical welding dry extension length. Programming is done in the following steps: 1) Calibration First, the position of the laser distance sensor (14) is calibrated so that the irradiated light spot coincides with the TCP point of the robot. Specifically, the nozzle and the conductive nozzle on the robot welding gun are first removed, and then the TCP calibration pin (8) is tightened on the welding gun. The robot is moved so that the tip of the TCP calibration pin (8) is aligned with the center of the cross line of the TCP calibration block (9). Three different postures are repeated and the robot position point is recorded in the program. Then, the TCP calibration pin (8) is unscrewed; the positioning sleeve (16) equipped with the laser distance sensor (14) and the sensor protection cover (15) is installed. Tighten it on the welding gun, move the robot to the first position point just recorded, adjust the three set screws (11) on the positioning sleeve (16) so that the light spot of the laser distance sensor (14) is irradiated at the center of the cross line, and then perform zeroing operation on the teaching controller (6). At this time, the distance displayed by the teaching controller (6) is 0. Then continue to move the robot to the other two points respectively, check the position of the light spot and the distance value displayed by the teaching controller (6). If there is any deviation, adjust the position of the laser distance sensor (14) until the deviations of the three positions are within a small range, and the calibration work is completed; 2) Teaching programming When in use, the operator controls the robot to use a welding gun with a laser distance sensor (14) to teach the workpiece (4), determines the welding wire pointing position through the laser light spot, and determines the welding wire dry extension length through the value displayed by the teaching controller (6). After the teaching programming is completed, the auxiliary device is disassembled, the conductive nozzle and the nozzle of the original welding gun are installed, and trial welding production can be carried out.
2. A laser-assisted teaching programming method for robot welding according to claim 1, characterized in that: The teaching controller (6) and the power supply (5) are fixed on the arm of the welding robot via a power supply mounting plate (7).
3. The laser-assisted teaching programming method for robot welding according to claim 1 is characterized in that: The cross lines on the plane of the TCP calibration block (9) have a line width of 0.5 mm and a line depth of less than 0.1 mm.
4. The laser-assisted teaching programming method for robot welding according to claim 1 is characterized in that: The rear end of the positioning sleeve (16) is provided with an opening, and the cable (13) at the signal output end of the laser distance measuring sensor (14) passes through the opening.
5. The laser-assisted teaching programming method for robot welding according to claim 1 is characterized in that: The outer diameter of the rear end of the sensor protection sleeve (15) is 0.5 mm smaller than the inner diameter of the positioning sleeve (16).
6. The laser-assisted teaching programming method for robot welding according to claim 1 is characterized in that: The output voltage of the power supply (5) is 24V.