An automatic welding device for a lower side door, its welding method and application

Abstract

The present invention relates to the technical field of lower side door welding, and specifically relates to an automatic welding device for a lower side door, its welding method and application. It includes a welding table, a conveying mechanism, a measuring mechanism, a clamping mechanism and a welding mechanism arranged on the welding table; the conveying mechanism is used for automatically conveying the lower side door, the measuring mechanism is arranged on the side of the conveying mechanism and is used for measuring the size of the lower side door during the conveying process, the clamping mechanism is arranged on the upper end surface of the welding table and is used for fixing the position of the lower side door before welding, and the welding mechanism is arranged on both sides of the welding table. The present invention can achieve real-time precise positioning of the weld seam during the welding process of the lower side door, high-quality welding of each weld bead, reduce working errors and the labor intensity of workers, and improve work efficiency while ensuring product quality.

Description

Technical Field

[0001] The present invention relates to the technical field of lower door welding, and specifically provides an automatic welding device for lower doors, its welding method and application. Background Art

[0002] Arc welding refers to using an electric arc as a heat source, utilizing the physical phenomenon of air discharge to convert electrical energy into the heat and mechanical energy required for welding, thereby achieving the purpose of connecting metals. The main methods include shielded metal arc welding, submerged arc welding, gas shielded welding, etc. It is the most widely used and important fusion welding method, accounting for more than 60% of the total welding production.

[0003] In the actual production process, most of the electric welding work is completed through manual positioning and manual welding. However, the manual positioning accuracy is not precise enough, and manual welding is prone to deviation. The consistency of the welded workpiece products is poor, resulting in an extended working time of the product and an increased probability of defective products. As a result, many workpieces need to be reworked, increasing production costs, having low production efficiency, a poor working environment, and high labor intensity, affecting the production progress of the entire enterprise. Therefore, some enterprises will introduce automated robots for welding to improve work efficiency.

[0004] However, during the welding process of automated robots, situations such as workpiece clamping deviation and thermal deformation of sheet metal parts frequently occur. Therefore, after robot welding, manual repair welding is required, which not only fails to save labor costs but also increases the product repair rate. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the existing defects, and provide an automatic welding device for lower doors, its welding method and application, which can achieve real-time precise positioning of weld seams, high-quality welding of each weld bead, reduce working errors and the labor intensity of workers, ensure product quality while improving work efficiency, and effectively solve the problems in the background art.

[0006] To achieve the above object, the present invention provides the following technical solution: An automatic welding device for lower doors includes a welding table, a conveying mechanism, a measuring mechanism, a clamping mechanism, and a welding mechanism provided on the welding table; the conveying mechanism is used for automatically conveying the lower doors, the measuring mechanism is provided on the side of the conveying mechanism and is used for measuring the dimensions of the lower doors during the conveying process, the clamping mechanism is provided on the upper end surface of the welding table and is used for fixing the position of the lower doors before welding, and the welding mechanism is provided on both sides of the welding table;

[0007] A double-gun synchronous laser tracking component is provided on the welding mechanism;

[0008] The double-gun synchronous laser tracking component includes a welding execution component and a laser weld tracking sensor;

[0009] The welding execution component is arranged on the Y-axis of the welding mechanism and includes a moving module fixed on the Y-axis, a moving welding torch arranged on the moving module, and a fixed welding torch fixed on the free end of the Y-axis. The moving welding torch moves with the moving module, and the fixed welding torch moves with the Y-axis.

[0010] Furthermore,

[0011] The laser weld tracking sensor is arranged on one side of the welding mechanism and is used for real-time detection and tracking of the weld. The output end of the laser weld tracking sensor is electrically connected to the input end of an external single-chip microcomputer, the output end of the external single-chip microcomputer is electrically connected to the input end of the welding execution component, and the input end of the external single-chip microcomputer is electrically connected to the output end of an external power supply.

[0012] Furthermore, the conveying mechanism is a conveyor line arranged on the upper end surface of the welding table.

[0013] Furthermore, the clamping mechanism includes a longitudinal clamping cylinder, a transverse clamping cylinder, and a lateral clamping cylinder. The longitudinal clamping cylinder is arranged on the lower end surface of the welding table, the transverse clamping cylinder is arranged on the upper end surface of the welding table and is connected to the longitudinal cylinder, the lateral clamping cylinder is arranged on one side of the welding table. The longitudinal clamping cylinder is used to drive the transverse clamping cylinder to move up and down. The transverse clamping cylinder is used for positioning and clamping in the length direction of the lower side door, and the lateral clamping cylinder is used for positioning and clamping in the width direction of the lower side door. The longitudinal clamping cylinder, the transverse clamping cylinder, and the lateral clamping cylinder are all electrically connected to the output end of the external single-chip microcomputer.

[0014] Furthermore, the measuring mechanism includes a laser displacement sensor and a photoelectric sensor. The laser displacement sensor and the photoelectric sensor are both arranged on the top of the welding table, and the output ends of the laser displacement sensor and the photoelectric sensor are electrically connected to the input end of the external single-chip microcomputer. The input end of the external single-chip microcomputer is electrically connected to the output end of the external power supply.

[0015] Furthermore, it further includes a clamping auxiliary mechanism. The clamping auxiliary mechanism is arranged on the cylinder expansion rods of the transverse clamping cylinder and the lateral clamping cylinder and includes a "∑"-shaped fixing bracket for fixing the cylinder and the clamping auxiliary mechanism, and two groups of connecting rod assemblies symmetrically arranged on the upper and lower sides of the fixing bracket. The connecting rod assembly includes a first straight rod and a second straight rod rotatably connected to the fixing bracket, a right-angle rod rotatably connected to both the first straight rod and the second straight rod, and a rotating rod rotatably connected to the center of the second straight rod and the cylinder expansion rod respectively.

[0016] Further, a cylindrical through-hole is provided at the center of the fixing bracket for accommodating the cylinder telescopic rod. The right-angle of the right-angle rod is rotatably connected to the second straight rod, and one end of one right-angle side of the right-angle rod is rotatably connected to the first straight rod. The distance between the connection points of the first straight rod and the second straight rod to the fixing bracket is equal to the length of the right-angle side of the right-angle rod connected to the first straight rod, and a spring clamping pad is provided at the free end of the right-angle rod.

[0017] The present invention also includes a welding method for an automatic lower-side door welding device. The welding method is as follows:

[0018] (1) The lower-side door is conveyed by a conveying mechanism.

[0019] (2) During the conveying process, a measuring mechanism performs positioning measurement on the lower-side door.

[0020] (3) When the lower-side door is conveyed to the designated position, the clamping mechanism is activated to clamp the lower-side door.

[0021] (4) The welding mechanism performs tracking and positioning welding on the weld seam.

[0022] Further, the specific steps of the welding method are as follows:

[0023] (11) The lower-side door is conveyed forward by the conveying line on the welding table. When the lower-side door passes through the first photoelectric sensor in the photoelectric sensors, the speed slows down. When it passes through the second photoelectric sensor in the photoelectric sensors, the conveying line stops conveying and the lower-side door stops.

[0024] (12) The external single-chip microcomputer calculates the size of the lower-side door in the length direction by calculating the time for the lower-side door to pass through the two photoelectric sensors and the running speed of the conveying line, and measures the width of the lower-side door through a laser displacement sensor.

[0025] (13) The external single-chip microcomputer transmits the data of the lower-side door size to the clamping mechanism. The clamping mechanism drives the transverse clamping cylinder to move up and down through the longitudinal clamping cylinder. The transverse clamping cylinder realizes transverse length clamping, and the lateral clamping cylinder extends to position and clamp the width of the lower-side door, achieving precise positioning in the width direction of the lower-side door.

[0026] (14) The welding mechanism calls the pre-stored welding program and performs welding through the double-gun synchronous laser tracking component. The laser weld tracking sensor monitors the weld seam in real time and transmits it to the external single-chip microcomputer. The external single-chip microcomputer sends the monitoring result to the welding execution component. The fixed welding torch moves along the Y-axis, and the moving welding torch moves along the moving module on the Y-axis, cooperating with the laser weld tracking sensor to correct the welding trajectory.

[0027] The present invention also includes an application of an automatic lower-side door welding device. The welding device is used for an independent workstation or applied to a complete lower-side door production line.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] The present invention can realize the automatic welding of the lower door panel and the tracking welding of the double-gun synchronous laser tracking component. The double welding guns move and position accurately, and are respectively equipped with laser weld tracking sensors, which can realize real-time communication with an external single-chip microcomputer to track the weld seam for welding. It installs eyes on the welding execution component, tracks and locates the weld seam in real time, realizes precise welding, cures the common problems of workpiece clamping deviation and sheet metal thermal deformation that occur during the welding process of blind welding robots, reduces the working error and the labor intensity of workers, improves the working efficiency while ensuring the product quality, and realizes high-quality welding of each weld bead. Description of the Drawings

[0030] Figure 1 It is the front view structural schematic diagram of the embodiment of the present invention;

[0031] Figure 2 It is the side view structural schematic diagram of the embodiment of the present invention;

[0032] Figure 3 It is the front view structural schematic diagram of the clamping mechanism of the embodiment of the present invention;

[0033] Figure 4 It is the top view structural schematic diagram of the clamping mechanism of the embodiment of the present invention;

[0034] Figure 5 It is the structural schematic diagram of the double-gun synchronous laser tracking component of the embodiment of the present invention;

[0035] Figure 6 It is the three-dimensional structural schematic diagram of the clamping auxiliary mechanism of the embodiment of the present invention;

[0036] Figure 7 It is the connection structural schematic diagram when the clamping auxiliary mechanism of the embodiment of the present invention is clamped;

[0037] Figure 8 It is the connection structural schematic diagram when the clamping auxiliary mechanism of the embodiment of the present invention is loosened;

[0038] Figure 9 It is the exploded view of the connection structure of the clamping auxiliary mechanism of the embodiment of the present invention.

[0039] In the figure:

[0040] Conveyor line; 2. Welding mechanism; 3. Photoelectric sensor; 4. Laser displacement sensor; 5. Clamping mechanism; 6. Longitudinal clamping cylinder; 7. Transverse clamping cylinder; 8. Lateral clamping cylinder; 9. Double-gun synchronous laser tracking assembly; 10. Fixed welding torch; 11. Moving welding torch; 12. Moving module; 13. Welding table; 14. Cylinder telescopic rod; 15. Fixed bracket; 16. First straight rod; 17. Second straight rod; 18. Right-angle rod; 19. Rotating rod; 20. Spring clamping pad. Detailed implementation mode

[0041] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention. Embodiment 1

[0042] As Figures 1-5 shown, an automatic welding device for the lower side door includes a welding table 13, a conveying mechanism, a measuring mechanism, a clamping mechanism 5 and a welding mechanism 2 provided on the welding table 13; the conveying mechanism is used to automatically convey the lower side door, the measuring mechanism is provided on the side of the conveying mechanism and is used to measure the size of the lower side door during the conveying process, the clamping mechanism 5 is provided on the upper end surface of the welding table 13 and is used to fix the position of the lower side door before welding, and the welding mechanism 2 is provided on both sides of the welding table 13;

[0043] The welding mechanism 2 is provided with a double-gun synchronous laser tracking assembly 9; the double-gun synchronous laser tracking assembly 9 includes a welding execution assembly and a laser weld tracking sensor;

[0044] The welding execution assembly is provided on the Y-axis of the welding mechanism 2 and includes a moving module 12 fixed on the Y-axis, a moving welding torch 11 provided on the moving module 12, and a fixed welding torch 10 fixed at the free end of the Y-axis. The moving welding torch 11 moves with the moving module 12, and the fixed welding torch 10 moves with the Y-axis. The laser weld tracking sensor completes the online real-time detection of common welds through complex program algorithms. There are corresponding function settings for the detection range, detection ability, and common problems during the welding process. The device calculates the deviation between the detected weld and the welding torch, outputs the deviation data, and the welding execution assembly corrects the deviation in real time to accurately guide the welding torch to automatically weld, thereby realizing the intelligent real-time tracking of the weld during the welding process.

[0045] The laser weld tracking sensor is provided at the end of the welding execution component on the welding mechanism 2 for real-time detection and tracking of the weld. The output end of the laser weld tracking sensor is electrically connected to the input end of an external single-chip microcomputer. The output end of the external single-chip microcomputer is electrically connected to the input end of the welding execution component, and the input end of the external single-chip microcomputer is electrically connected to the output end of an external power supply. A welding program is stored in the external single-chip microcomputer. According to the specifications of the lower side door to be welded detected by the laser displacement sensor, the welding program is correspondingly called from the system, and the welding mechanism 2 automatically welds without manual intervention throughout the process. The working conditions are good. The welding execution component and the laser weld tracking sensor can achieve high-quality weld beads, reduce deviations, have high production efficiency, and good welding quality.

[0046] The laser weld tracking sensor adopts the principle of laser triangulation reflection, that is, the laser beam is amplified to form a laser line and projected onto the surface of the object to be measured. The reflected light passes through a high-quality optical system and is projected onto an imaging matrix. The distance (Z-axis) from the sensor to the measured surface and the position information (X-axis) along the laser line are obtained through calculation. By moving the object to be measured or the probe of the profiler, a set of three-dimensional measurement values can be obtained.

[0047] The information obtained can be used for weld search and positioning, weld tracking, adaptive control of welding parameters, weld formation detection, and real-time transmission of information to the welding execution component to complete various complex welds, avoid welding quality deviations, and achieve unmanned welding.

[0048] The conveying mechanism is a conveyor line 1 provided on the upper end surface of the welding table 13. Only manual labor is required to place the loose parts on the conveyor line 1, and the conveyor rollers on the conveyor line 1 convey the loose parts of the lower side door to the positioning place without manual handling.

[0049] The clamping mechanism 5 includes a longitudinal clamping cylinder 6, a transverse clamping cylinder 7, and a lateral clamping cylinder 8. The longitudinal clamping cylinder 6 is provided on the lower end surface of the welding table 13. The transverse clamping cylinder 7 is provided on the upper end surface of the welding table 13 and is connected to the longitudinal cylinder 6. The lateral clamping cylinder 8 is provided on one side of the welding table 13. The longitudinal clamping cylinder 6 is used to drive the transverse clamping cylinder 7 to move up and down. The transverse clamping cylinder 7 is used to position and clamp the lower side door in the length direction. The lateral clamping cylinder 8 is used to position and clamp the lower side door in the width direction. The longitudinal clamping cylinder 6, the transverse clamping cylinder 7, and the lateral clamping cylinder 8 are all electrically connected to the output end of the external single-chip microcomputer.

[0050] The measuring mechanism includes a laser displacement sensor 4 and a photoelectric sensor 3. The laser displacement sensor 4 and the photoelectric sensor 3 are both arranged at the top of the welding table 13, and the output ends of the laser displacement sensor 4 and the photoelectric sensor 3 are electrically connected to the input end of an external single-chip microcomputer. The laser displacement sensor 4 and the photoelectric sensor 3 are used to determine the specification dimensions of the lower side door under various specifications. There are two photoelectric sensors 3, which are respectively used to detect the input and output of the lower side door. The laser displacement sensor 4 is used to detect the width of the lower side door to facilitate the positioning of the lower side door.

[0051] The present invention also includes a welding method for the automatic welding device of the lower side door. The welding method is as follows:

[0052] (1) The lower side door is conveyed by a conveying mechanism;

[0053] (2) During the conveying process, the measuring mechanism performs positioning measurement on the lower side door;

[0054] (3) When the lower side door is conveyed to the designated position, the clamping mechanism 5 is activated to clamp the lower side door;

[0055] (4) The welding mechanism 2 performs tracking and positioning welding on the weld seam.

[0056] The specific steps of the welding method are as follows:

[0057] (11) The lower side door is conveyed forward through the conveying line 1 on the welding table. When the lower side door passes through the first photoelectric sensor 3 of the photoelectric sensor 3, the speed slows down. When it passes through the second photoelectric sensor 3 of the photoelectric sensor 3, the conveying line 1 stops conveying and the lower side door stops;

[0058] (12) The external single-chip microcomputer calculates the size of the lower side door in the length direction by calculating the time for the lower side door to pass through the two photoelectric sensors 3 and the running speed of the conveying line 1; and measures the width of the lower side door through the laser displacement sensor 4;

[0059] (13) The external single-chip microcomputer transmits the data of the lower side door size to the clamping mechanism 5. The clamping mechanism 5 drives the transverse clamping cylinder 7 to move up and down through the longitudinal clamping cylinder 6. The transverse clamping cylinder 7 realizes transverse length clamping, and the lateral clamping cylinder 8 extends to position and clamp the width of the lower side door, realizing precise positioning in the width direction of the lower side door;

[0060] (14) The welding mechanism 2 calls the pre-stored welding program and performs welding through the double-gun synchronous laser tracking component 9. The laser weld tracking sensor monitors the weld seam in real time and transmits it to the external single-chip microcomputer. The external single-chip microcomputer sends the monitoring result to the welding execution component. The fixed welding torch 10 moves along the Y-axis, and the moving welding torch 11 moves along the moving module 12 on the Y-axis, cooperating with the laser weld tracking sensor to realize the correction of the welding trajectory.

[0061] The present invention also includes an application of an automatic welding device for the lower side door, and the welding device is used for an independent workstation or applied to a complete lower side door production line.

[0062] Due to the deviation in the blanking accuracy of the lower side door workpiece, with a deviation value of about ±1.5 mm, it has a certain impact on the welding quality. Configuring a laser weld tracking sensor can reduce the welding error. The basic principle of the laser weld tracking sensor is based on the laser triangulation measurement method. The laser emitter emits a line laser that irradiates the surface of the workpiece, and then after diffuse reflection, the laser profile is imaged on a CCD or CMOS sensor. Then the controller processes and analyzes the collected image to obtain the position of the weld seam, which is used to correct the welding trajectory or guide the welding. Laser tracking means using a laser vision sensor to detect ahead of the welding torch, and calculating the position coordinates of the sensor measurement point based on the pre-calibrated positional relationship between the laser vision sensor and the welding torch. During the welding process, the taught position of the robot is compared with the detected position of the sensor, and the position deviation of the corresponding point is calculated. When the welding torch lagging behind the laser line reaches the corresponding detection position, the deviation is compensated to the current welding trajectory to achieve the purpose of correcting the welding trajectory.

[0063] Laser position finding means using a laser sensor to perform a single measurement on the position to be measured and calculating the position of the target point. Generally, for relatively short weld seams or when using laser tracking will interfere with the tooling fixture, laser position finding is used to correct the weld seam. Compared with laser tracking, the function of laser position finding is relatively simple, and the implementation and operation are also more convenient.

[0064] Compared with traditional manual welding, which is time-consuming and laborious and has excessively high various cost expenses, the present invention uses a laser displacement sensor and laser weld tracking and position finding. The laser displacement sensor automatically measures the length and width of the lower side door, and the teaching program corresponds to each measurement value one by one; the weld seam is corrected by using the form of laser tracking and position finding to ensure the welding quality.

[0065] It should be noted that the specific model of the external single-chip microcomputer disclosed in this embodiment is ATMEGA16L-8AU, the preferred model of the clamping cylinder is RPG-120-P, the preferred model of the photoelectric sensor is WL2SG-2P3235, the preferred model of the laser sensor is ZX2-LD100, and the external single-chip microcomputer controls the clamping cylinder to work by using a method commonly used in the prior art. Embodiment 2

[0066] Such as Figures 1-9As shown in the figure, an automatic welding device for the lower side door includes a welding table 13, a conveying mechanism, a measuring mechanism, a clamping mechanism 5 and a welding mechanism 2 provided on the welding table 13; the conveying mechanism is used to automatically convey the lower side door, the measuring mechanism is provided on the side of the conveying mechanism and is used to measure the size of the lower side door during the conveying process, the clamping mechanism 5 is provided on the upper end surface of the welding table 13 and is used to fix the position of the lower side door before welding, and the welding mechanism 2 is provided on both sides of the welding table 13;

[0067] A double-gun synchronous laser tracking component 9 is provided on the welding mechanism 2; the double-gun synchronous laser tracking component 9 includes a welding execution component and a laser weld tracking sensor;

[0068] The welding execution component is provided on the Y-axis of the welding mechanism 2 and includes a moving module 12 fixed on the Y-axis, a moving welding gun 11 provided on the moving module 12, and a fixed welding gun 10 fixed on the free end of the Y-axis. The moving welding gun 11 moves with the moving module 12, and the fixed welding gun 10 moves with the Y-axis. The laser weld tracking sensor completes the on-line real-time detection of common welds through complex program algorithms. There are corresponding function settings for the detection range, detection ability and common problems during the welding process. The device calculates the deviation between the detected weld and the welding gun, outputs the deviation data, and the welding execution component corrects the deviation in real time to accurately guide the automatic welding of the welding gun, so as to realize the intelligent real-time tracking of the weld during the welding process.

[0069] The laser weld tracking sensor is provided at the end of the welding execution component on the welding mechanism 2 and is used to perform real-time detection and tracking of the weld. The output end of the laser weld tracking sensor is electrically connected to the input end of an external single-chip microcomputer, the output end of the external single-chip microcomputer is electrically connected to the input end of the welding execution component, and the input end of the external single-chip microcomputer is electrically connected to the output end of an external power supply. The external single-chip microcomputer stores welding programs. According to the specification size of the lower side door to be welded detected by the laser displacement sensor, the welding programs are called from the system correspondingly, and the welding mechanism 2 automatically welds without manual intervention throughout the process. The working conditions are good. The welding execution component and the laser weld tracking sensor can achieve high-quality weld beads, reduce deviations, have high production efficiency and good welding quality.

[0070] The laser weld tracking sensor adopts the principle of laser triangulation reflection, that is, the laser beam is amplified to form a laser line and projected onto the surface of the object to be measured. The reflected light passes through a high-quality optical system and is projected onto an imaging matrix. The distance (Z-axis) from the sensor to the measured surface and the position information (X-axis) along the laser line are obtained through calculation. Moving the object to be measured or the probe of the profiler can obtain a set of three-dimensional measurement values.

[0071] The information obtained can be used for weld search and positioning, weld tracking, adaptive control of welding parameters, weld formation detection, and real-time transmission of information to the welding execution component to complete various complex weldings, avoid welding quality deviation, and achieve unmanned welding.

[0072] The conveying mechanism is a conveying line 1 provided on the upper end surface of the welding table 13. Only manual labor is required to place the loose parts on the conveying line 1, and the conveying rollers on the conveying line 1 convey the lower door loose parts to the positioning place without manual handling.

[0073] The clamping mechanism 5 includes a longitudinal clamping cylinder 6, a transverse clamping cylinder 7, and a lateral clamping cylinder 8. The longitudinal clamping cylinder 6 is provided on the lower end surface of the welding table 13. The transverse clamping cylinder 7 is provided on the upper end surface of the welding table 13 and is connected to the longitudinal cylinder 6. The lateral clamping cylinder 8 is provided on one side of the welding table 13. The longitudinal clamping cylinder 6 is used to drive the transverse clamping cylinder 7 to move up and down. The transverse clamping cylinder 7 is used to position and clamp the lower door in the length direction. The lateral clamping cylinder 8 is used to position and clamp the lower door in the width direction. The longitudinal clamping cylinder 6, the transverse clamping cylinder 7, and the lateral clamping cylinder 8 are all electrically connected to the output end of an external single-chip microcomputer.

[0074] The measuring mechanism includes a laser displacement sensor 4 and a photoelectric sensor 3. The laser displacement sensor 4 and the photoelectric sensor 3 are both provided at the top of the welding table 13, and the output ends of the laser displacement sensor 4 and the photoelectric sensor 3 are electrically connected to the input end of an external single-chip microcomputer. The laser displacement sensor 4 and the photoelectric sensor 3 are used to determine the specification dimensions of the lower door under various specifications. There are two photoelectric sensors 3, which are respectively used to detect the input and output of the lower door. The laser displacement sensor 4 is used to detect the width of the lower door to facilitate positioning of the lower door.

[0075] It further includes a clamping auxiliary mechanism. The clamping auxiliary mechanism is provided on the cylinder expansion rods 14 of the transverse clamping cylinder 7 and the lateral clamping cylinder 8, and includes a "∑"-shaped fixing bracket 15 for fixing the cylinder and the clamping auxiliary mechanism, and two groups of connecting rod assemblies symmetrically arranged on the upper and lower sides of the fixing bracket 15. The connecting rod assembly includes a first straight rod 16 and a second straight rod 17 rotatably connected to the fixing bracket 15, a right-angle rod 18 rotatably connected to both the first straight rod 16 and the second straight rod 17, and a rotating rod 19 rotatably connected to the center of the second straight rod 17 and the cylinder expansion rod 14 respectively. A cylindrical through hole is provided at the center of the fixing bracket 15 for accommodating the cylinder expansion rod 14. The right-angle of the right-angle rod 18 is rotatably connected to the second straight rod 17, and one end of one right-angle side of the right-angle rod 18 is rotatably connected to the first straight rod 16. The distance between the connection points of the first straight rod 16 and the second straight rod 17 with the fixing bracket 15 is equal to the length of the right-angle side of the right-angle rod 18 connected to the first straight rod 16. A spring clamping pad 20 is provided at the free end of the right-angle rod 18.

[0076] The output end of the clamping auxiliary mechanism is connected to the input end of an external single-chip microcomputer, and is used to fixedly clamp the lower door during the welding process. Figure 7 It is a schematic diagram of the connection structure when the clamping auxiliary mechanism clamps. Figure 8 It is a schematic diagram of the connection structure when the clamping auxiliary mechanism releases.

[0077] The present invention also includes a welding method for the automatic welding device of the lower door. The welding method is as follows:

[0078] (1) The lower door is conveyed by a conveying mechanism.

[0079] (2) During the conveying process, a measuring mechanism performs positioning measurement on the lower door.

[0080] (3) When the lower door is conveyed to the designated position, the clamping mechanism 5 is activated to clamp the lower door.

[0081] (4) The welding mechanism 2 performs tracking and positioning welding on the weld seam.

[0082] The specific steps of the welding method are as follows:

[0083] (11) The lower door is conveyed forward by the conveying line 1 on the welding table. When the lower door passes through the first photoelectric sensor 3 in the photoelectric sensor 3, the speed slows down. When it passes through the second photoelectric sensor 3 in the photoelectric sensor 3, the conveying line 1 stops conveying and the lower door stops.

[0084] (12) The external single-chip microcomputer calculates the size of the lower door in the length direction by calculating the time for the lower door to pass through the two photoelectric sensors 3 and the running speed of the conveying line 1; and measures the width of the lower door through the laser displacement sensor 4.

[0085] (13) The external single-chip microcomputer transmits the data of the lower door size to the clamping mechanism 5. The clamping mechanism 5 drives the transverse clamping cylinder 7 to move up and down through the longitudinal clamping cylinder 6. The transverse clamping cylinder 7 realizes transverse length clamping, and the lateral clamping cylinder 8 extends to position and clamp the width of the lower door, realizing precise positioning in the width direction of the lower door.

[0086] (14) The welding mechanism 2 calls the pre-stored welding program and performs welding through the double-gun synchronous laser tracking component 9. The laser weld tracking sensor monitors the weld seam in real time and transmits it to the external single-chip microcomputer. The external single-chip microcomputer sends the monitoring result to the welding execution component. The fixed welding torch 10 moves along the Y-axis, and the moving welding torch 11 moves along the moving module 12 on the Y-axis, cooperating with the laser weld tracking sensor to realize the correction of the welding trajectory.

[0087] The present invention also includes an application of the automatic welding device for the lower door. The welding device is used for an independent workstation or applied in a complete production line of the lower door.

[0088] Due to the deviation in the blanking accuracy of the lower side door workpiece, with a deviation value of about ±1.5 mm, it has a certain impact on the welding quality. Configuring a laser weld tracking sensor can reduce the welding error. The basic principle of the laser weld tracking sensor is based on the laser triangulation measurement method. The laser emitter emits a line laser that irradiates the surface of the workpiece, and then after diffuse reflection, the laser profile is imaged on a CCD or CMOS sensor. Then, the controller processes and analyzes the collected image to obtain the position of the weld seam, which is used to correct the welding trajectory or guide the welding. Laser tracking means using a laser vision sensor to detect ahead of the welding torch, and calculating the position coordinates of the sensor measurement point based on the pre-calibrated position relationship between the laser vision sensor and the welding torch. During the welding process, the taught position of the robot is compared with the detected position of the sensor, and the position deviation of the corresponding point is calculated. When the welding torch lagging behind the laser line reaches the corresponding detection position, the deviation is compensated to the current welding trajectory to achieve the purpose of correcting the welding trajectory.

[0089] Laser position finding means using a laser sensor to perform a single measurement on the position to be measured and calculating the position of the target point. Generally, for relatively short weld seams or when using laser tracking will interfere with the tooling fixture, the form of laser position finding is used to correct the weld seam. Compared with laser tracking, the function of laser position finding is relatively simple, and the implementation and operation are also more convenient.

[0090] Compared with traditional manual welding, it is time-consuming and laborious, and the various cost expenses are too high. The present invention uses a laser displacement sensor and laser weld tracking and position finding. The laser displacement sensor automatically measures the length and width of the lower side door, and the teaching program corresponds to each measurement value one by one; the form of laser tracking and position finding is used to correct the weld seam to ensure the welding quality.

[0091] It should be noted that the specific model of the external single-chip microcomputer disclosed in this embodiment is ATMEGA16L-8AU, the preferred model of the clamping cylinder is RPG-120-P, the preferred model of the photoelectric sensor is WL2SG-2P3235, the preferred model of the laser sensor is ZX2-LD100, and the external single-chip microcomputer controls the clamping cylinder to work using the commonly used method in the prior art.

[0092] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An automatic welding device for the lower side door, characterized in that: It includes a welding table, a conveying mechanism, a measuring mechanism, a clamping mechanism and a welding mechanism provided on the welding table; the conveying mechanism is used for automatically conveying the lower side door, the measuring mechanism is provided on the side of the conveying mechanism and is used for measuring the size of the lower side door during the conveying process, the clamping mechanism is provided on the upper end surface of the welding table and is used for fixing the position of the lower side door before welding, and the welding mechanism is provided on both sides of the welding table; A double-gun synchronous laser tracking assembly is provided on the welding mechanism; The double-gun synchronous laser tracking assembly includes a welding execution assembly and a laser weld tracking sensor; The welding execution assembly is provided on the Y-axis of the welding mechanism and includes a moving module fixed on the Y-axis, a moving welding gun provided on the moving module, and a fixed welding gun fixed on the free end of the Y-axis. The moving welding gun moves with the moving module, and the fixed welding gun moves with the Y-axis; The laser weld tracking sensor is provided on one side of the welding mechanism and is used for real-time detection and tracking of the weld. The output end of the laser weld tracking sensor is electrically connected to the input end of an external single-chip microcomputer, the output end of the external single-chip microcomputer is electrically connected to the input end of the welding execution assembly, and the input end of the external single-chip microcomputer is electrically connected to the output end of an external power supply; The clamping mechanism includes a longitudinal clamping cylinder, a transverse clamping cylinder and a lateral clamping cylinder. The longitudinal clamping cylinder is provided on the lower end surface of the welding table, the transverse clamping cylinder is provided on the upper end surface of the welding table and is connected to the longitudinal cylinder, the lateral clamping cylinder is provided on one side of the welding table. The longitudinal clamping cylinder is used for driving the transverse clamping cylinder to move up and down. The transverse clamping cylinder is used for positioning and clamping the lower side door in the length direction, and the lateral clamping cylinder is used for positioning and clamping the lower side door in the width direction. The longitudinal clamping cylinder, the transverse clamping cylinder and the lateral clamping cylinder are all electrically connected to the output end of the external single-chip microcomputer; The measuring mechanism includes a laser displacement sensor and a photoelectric sensor. The laser displacement sensor and the photoelectric sensor are both provided on the top of the welding table, and the output ends of the laser displacement sensor and the photoelectric sensor are electrically connected to the input end of the external single-chip microcomputer. The input end of the external single-chip microcomputer is electrically connected to the output end of the external power supply; There are two photoelectric sensors, which are respectively used to detect the input and output of the lower side door. The laser displacement sensor is used to detect the width of the lower side door. The external single-chip microcomputer calculates the size of the lower side door in the length direction by calculating the time when the lower side door passes through the two photoelectric sensors and the running speed of the conveying mechanism, measures the width of the lower side door through the laser displacement sensor, and the external single-chip microcomputer transmits the data of the lower side door size to the clamping mechanism.

2. The automatic welding device for the lower side door according to claim 1, wherein: The conveying mechanism is a conveying line provided on the upper end surface of the welding table.

3. The automatic welding device for the lower side door according to claim 1, wherein: It further includes a clamping auxiliary mechanism, which is arranged on the cylinder expansion rods of the transverse clamping cylinder and the lateral clamping cylinder, and includes a "∑"-shaped fixing bracket for fixing the cylinder and the clamping auxiliary mechanism, and two sets of connecting rod assemblies symmetrically arranged on the upper and lower sides of the fixing bracket. The connecting rod assembly includes a first straight rod and a second straight rod rotatably connected to the fixing bracket, a right-angle rod rotatably connected to both the first straight rod and the second straight rod, and a rotating rod rotatably connected to the center of the second straight rod and the cylinder expansion rod respectively.

4. The automatic welding device for the lower side door according to claim 3, characterized in that: A cylindrical through-hole is provided at the center of the fixing bracket for accommodating the cylinder expansion rod. The right-angle of the right-angle rod is rotatably connected to the second straight rod, and the end of one of the right-angle sides of the right-angle rod is rotatably connected to the first straight rod; the distance between the connection points of the first straight rod and the second straight rod with the fixing bracket is equal to the length of the right-angle side of the right-angle rod connected to the first straight rod, and a spring clamping pad is provided at the free end of the right-angle rod.

5. A welding method for the lower side door automatic welding device according to any one of claims 1-4, characterized in that, The welding method is as follows: (11) The lower side door is conveyed forward through the conveying line on the welding table. When the lower side door passes through the first photoelectric sensor in the photoelectric sensors, the speed slows down. When it passes through the second photoelectric sensor in the photoelectric sensors, the conveying line stops conveying and the lower side door stops. (12) The external single-chip microcomputer calculates the size in the length direction of the lower side door by calculating the time for the lower side door to pass through the two photoelectric sensors and the running speed of the conveying line; and measures the width of the lower side door through a laser displacement sensor. (13) The external single-chip microcomputer transmits the data of the lower side door size to the clamping mechanism. The clamping mechanism drives the transverse clamping cylinder to move up and down through the longitudinal clamping cylinder. The transverse clamping cylinder realizes transverse length clamping, and the lateral clamping cylinder extends to position and clamp the width of the lower side door, realizing precise positioning in the width direction of the lower side door. (14) The welding mechanism calls the pre-stored welding program and performs welding through the double-gun synchronous laser tracking component. The laser weld tracking sensor monitors the weld in real time and transmits it to the external single-chip microcomputer. The external single-chip microcomputer sends the monitoring result to the welding execution component. The fixed welding gun moves along the Y-axis, and the moving welding gun moves along the moving module on the Y-axis, and cooperates with the laser weld tracking sensor to realize the correction of the welding trajectory.

6. The application of an automatic welding device for the lower side door, wherein the automatic welding device for the lower side door has any one of claims 1-4 The structure described in item [ID], or used in the welding method described in claim 5, is characterized in that: the said welding device is used for an independent workstation or applied in a complete production line of the lower side door.

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