Integrated robot servo bump welding gun and monitoring method

Abstract

The invention belongs to the technical field of welding production, and particularly relates to an integrated robot servo bump welding gun and a monitoring method. The welding gun comprises a gun body assembly, an electrode arm, a nut retainer and a displacement sensor. The gun body assembly is arranged on the robot body, a driving motor and a transformer are arranged on the upper side and the lower side of the gun body assembly respectively, a first convex spot welding electrode is arranged at the driving end of the driving motor, and the nut retainer is arranged at the end of the first convex spot welding electrode; the electrode arm is arranged on the lower side of the gun body assembly and electrically connected with the transformer. The electrode arm is provided with a second convex spot welding electrode; the driving motor, the transformer and the displacement sensor are all electrically connected with the robot body. The method can adapt to salient point welding of different workpieces, parameters in the welding process are monitored in real time and compared with preset parameters for analysis, the welding quality problem is found and solved in time, potential faults are early warned in advance, and the downtime and maintenance cost of equipment are reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of welding production, specifically relates to the field of projection welding, and particularly relates to an integrated robot servo projection spot welding gun and a monitoring method. Background Art

[0002] In the development of modern manufacturing, welding technology is the key to determining product quality and production efficiency. With the increasing requirements of manufacturing for precision, strength, and efficiency, projection spot welding technology has gradually become an important breakthrough direction in the welding field: Projection spot welding is a special resistance spot welding method. Protrusions are processed on the contact surface of the workpieces. When current passes through, the resistance of the protrusions is large and the current density is high, and the protrusions are quickly heated and melted to form welding spots.

[0003] The existing fixed projection spot welding guns have some obvious disadvantages in practical applications: First, the flexibility is severely limited. The fixed position and angle make it only applicable to welding workpieces with specific shapes and positions. Once the design or production process of the workpieces changes, it is often necessary to redesign and install the spot welding gun, and the adjustment is difficult and costly; Second, the maintenance cost of the fixed projection spot welding gun is relatively high. Due to its relatively complex structure, after long-term use, key components such as electrodes and transformers are prone to wear and failure, and the repair is difficult and takes a long time, which will lead to production interruption and increase the downtime cost of the enterprise. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides an integrated robot servo projection spot welding gun and a monitoring method to solve the problems that the flexibility of the existing fixed projection spot welding gun is severely limited, and once the design or production process of the workpieces changes, it is often necessary to redesign and install the spot welding gun, with difficult adjustment and high cost; and key components such as electrodes and transformers are prone to wear and failure, and the repair is difficult and takes a long time.

[0005] One aspect of the present invention provides an integrated robot servo projection spot welding gun, including: a robot main body, a gun body assembly, an electrode arm, a nut retainer, and a displacement sensor; The gun body assembly is arranged on the robot main body, and the robot main body is configured to drive the gun body assembly to move within the processing station; The gun body assembly is further provided with a driving motor and a transformer. The driving end of the driving motor is provided with a first projection spot welding electrode, and the nut retainer is arranged at the end of the first projection spot welding electrode; The electrode arm is arranged on the lower side of the gun body assembly, and the electrode arm is electrically connected to the transformer; The electrode arm is provided with a second projection spot welding electrode. The end of the first projection spot welding electrode is coaxially arranged with the second projection spot welding electrode, and the displacement sensor is arranged at the end of the second projection spot welding electrode; The driving motor, the transformer and the displacement sensor are all electrically connected to the robot body.

[0006] In one aspect of the present invention, the nut retainer is provided with a receiving hole matching the raised nut, for guiding the raised nut to enter and be positioned on the nut retainer. The end of the second projection welding electrode is provided with a positioning pin, the central axis of the positioning pin coincides with the central axis of the receiving hole, and the positioning pin is used for positioning the raised nut entering the receiving hole. Wherein, when the resistance welding gun is aligned with the workpiece, the second projection welding electrode abuts against the workpiece, and the displacement sensor is used to detect the alignment of the electrode arm with the welding reserved hole on the workpiece. Alternatively, after the resistance welding gun performs welding operations, the second projection welding electrode abuts against the workpiece and the raised nut, and the displacement sensor is used to detect the welding quality of the raised nut.

[0007] In one aspect of the present invention, a monitoring method is further provided, which can be used for the integrated robot servo projection welding gun described in any one of the above-mentioned aspects. An encoder is provided in the driving motor of the integrated robot servo projection welding gun, and at least a Hall sensor and a temperature sensor are provided in the electrode arm of the integrated robot servo projection welding gun. The encoder, the Hall sensor and the temperature sensor are electrically connected to a fault diagnosis and analysis device. The monitoring method includes: Obtaining the displacement data of the first projection welding electrode through the encoder. Obtaining the real-time current and voltage data in the electrode arm through the Hall sensor. Obtaining the real-time temperature data of the electrode arm and the cooling water pipeline through the temperature sensor. Taking the displacement data, the real-time current and voltage data and the real-time temperature data as welding parameters, inputting the welding parameters into the fault diagnosis and analysis device, analyzing the operating state of the device through a fault diagnosis algorithm. If the operating state of the device is abnormal, an abnormal alarm signal is generated in real time, and corresponding alarm action instructions are triggered according to the alarm level.

[0008] In one aspect of the present invention, it further includes: Before a welding operation, the contact depth between the positioning pin on the electrode arm and the workpiece guiding hole is detected by a displacement sensor provided at the end of the second projection welding electrode. If the depth does not reach the set value, it is determined that the alignment is abnormal. Alternatively, after a welding operation, the rebound displacement of the raised nut after welding with the workpiece is detected by a displacement sensor. If the rebound displacement is less than the preset value, it is determined that the welding nugget formation is incomplete, and a secondary welding process is triggered.

[0009] In one solution of the present invention, the welding parameters are input into the fault diagnosis and analysis device, and the analysis of the device operation state through the fault diagnosis algorithm includes: Comparing the displacement data with a preset motion trajectory to obtain displacement deviation data, and calculating displacement precision standard deviation data based on the displacement deviation data; Comparing and calculating the real-time current and voltage data with a preset threshold range to obtain current and voltage volatility; Comparing and calculating the real-time temperature data with a preset temperature curve to obtain electrode temperature rise data; Analyzing the displacement precision standard deviation data, the current and voltage volatility, and the electrode temperature rise data, and outputting the analysis result of the device operation state.

[0010] In one solution of the present invention, the alarm level triggers the alarm action instruction, including: Level 1 alarm: When there is an instantaneous overlimit in the welding parameters, the controller of the robot main body is triggered to record deviation data. The instantaneous overlimit means that the overlimit amplitude exceeds 10% of the rated value and the duration reaches 0.5 seconds.

[0011] In one solution of the present invention, the alarm level triggers the alarm action instruction, including: Level 2 alarm: When the number of instantaneous overlimits of the welding parameters in the same welding cycle exceeds a preset value, the controller of the robot main body is triggered to extend the welding interval by 2 seconds and display a warning icon through the HMI interface to prompt the operator to check.

[0012] In one solution of the present invention, the alarm level triggers the alarm action instruction, including: Level 3 alarm: When the first projection welding electrode has no displacement change during the operation of the drive motor in the non-welding state, the current drops suddenly by more than 20% of the rated value during the welding state, or the electrode arm temperature rise rate exceeds 30% of the rated value, the controller of the robot main body is triggered to output an emergency stop signal and execute it to cut off the transformer power supply, close the drive motor brake, and send an emergency stop alarm to the control center through the Ethernet.

[0013] In one solution of the present invention, a unique quality code is generated for each welding point according to the position, time, and process parameters of the welding point, and the quality code is associated with storing the original data and analysis results of the displacement data, current and voltage volatility, and electrode temperature rise data corresponding to the welding point in the database.

[0014] In one aspect of the present invention, it further includes: analyzing the trend of batch welding data based on quality coding through a machine learning model, where the machine learning model is a supervised learning model trained with historical welding data, and its input features include displacement data associated with quality coding, current-voltage volatility, electrode temperature rise data, and analysis results, and the output is the predicted value of electrode life and the predicted value of transformer performance degradation; specifically including: Calculating the positioning repeatability accuracy of the electrode. If the standard deviation of the positioning accuracy increases by more than 0.1 cm in several consecutive welds, prompt the need to maintain the electrode through the HMI interface and send a warning to the control center via Ethernet; Calculating the output power attenuation trend of the transformer. If the power attenuation exceeds 5% in several consecutive welds, prompt the need to maintain the transformer through the HMI interface and send a warning to the control center via Ethernet.

[0015] The integrated robot servo projection spot welding gun and the monitoring method provided by the present invention can achieve the following technical effects: 1. The integrated structure design of the robot main body and the projection spot welding gun ensures the stability and accuracy of their coordinated work. Among them, the robot main body drives the gun body assembly to move, cooperating with components such as a drive motor, a transformer, and a displacement sensor. The displacement sensor can accurately detect the alignment of the electrode arm with the workpiece and the welding quality of the projection nut, ensuring the accuracy and reliability of welding; and the robot servo projection spot welding gun can better adapt to the projection welding of different workpieces through multi-axis movement, reducing the adjustment time compared with conventional fixed projection welding equipment and improving production efficiency.

[0016] 2. By real-time monitoring the displacement data, current-voltage data, and temperature data during the welding process and comparing and analyzing them with preset parameters, welding quality problems can be discovered and solved in a timely manner, improving the strength and stability of the welding points.

[0017] 3. By generating a unique quality coding for each welding point and associating and storing various data during the welding process, the traceability of welding quality is achieved, and by analyzing the trend of batch welding data based on a machine learning model, the electrode life and the degradation of transformer performance can be predicted, and potential faults can be warned in advance, enabling maintenance personnel to perform preventive maintenance in a timely manner, reducing the downtime and maintenance costs of the equipment. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0019] Figure 1 Schematic structural diagram of the integrated robot servo projection spot welding gun of the present invention; Figure 2 Schematic diagram of the internal structure of the integrated robot servo projection spot welding gun of the present invention; Figure 3 Schematic structural diagram of the first projection spot welding electrode of the present invention; Figure 4 Schematic structural diagram of the second projection spot welding electrode of the present invention; Figure 5 Schematic flow diagram of the monitoring method of the present invention; Figure 6 Schematic flow diagram of the operation of the displacement sensor of the present invention; Figure 7 Schematic flow diagram of the analysis of the operating state of the equipment of the present invention.

[0020] The description of the reference numerals in the attached drawings is as follows: 1 - gun body assembly; 2 - electrode arm; 3 - nut retainer; 4 - displacement sensor; 5 - drive motor; 6 - transformer; 7 - first projection spot welding electrode; 8 - second projection spot welding electrode; 9 - projection nut; 10 - positioning pin; 11 - cooling water pipe; 12 - first flexible connector; 13 - second flexible connector. Specific embodiments

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with 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 of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0022] Embodiment 1 Please refer to Figures 1 - 4 , one embodiment of the present invention provides an integrated robot servo projection spot welding gun, including: a robot main body, a gun body assembly 1, an electrode arm 2, a nut retainer 3, and a displacement sensor 4; The gun body assembly 1 is arranged on the robot main body through a modular standard mounting flange, and the robot main body is configured to drive the gun body assembly 1 to move within the processing station; The gun body assembly 1 is further provided with a drive motor 5 and a transformer 6. The drive end of the drive motor 5 is provided with a first projection spot welding electrode 7, and the nut retainer 3 is arranged at the end of the first projection spot welding electrode 7; The electrode arm 2 is arranged on the lower side of the gun body assembly 1, and the electrode arm 2 is electrically connected to the transformer 6; The electrode arm 2 is provided with a second projection welding electrode 8. The end of the first projection welding electrode 7 is coaxially arranged with the second projection welding electrode 8, and the displacement sensor 4 is arranged at the end of the second projection welding electrode 8. The drive motor 5, the transformer 6 and the displacement sensor 4 are all electrically connected to the robot body.

[0023] Understandably, the robot body includes a fuselage, joints and an execution structure. The fuselage, as the support part of the whole robot, has high strength and stiffness, can fix and support other components, and its interior can accommodate some sensors, actuators and control systems, etc.; the joints are the core components of the robot's movement, usually composed of motors, reducers, transmission shafts and gears, etc., and can control the movement of the robot's arm or wrist in multiple directions to achieve various actions of the robot. Common joints include different structural forms such as joint coordinate form, rectangular coordinate form, cylindrical coordinate form, spherical coordinate form, etc.; the execution structure is composed of a series of joints and can perform complex actions such as grasping, rotating and placing; the gun body assembly 1 is arranged on the execution structure through a modular standard mounting flange.

[0024] The integrated robot servo projection welding gun provided by this embodiment can achieve the following technical effects: 1. The integrated structure design of the robot body and the projection welding gun ensures the stability and accuracy of their coordinated work. Among them, through the precise coordination of the drive motor 5, the nut retainer 3 and the displacement sensor 4, the whole process automation from taking the projection nut 9, applying pressure to resistance welding is realized; and, the displacement sensor 4 monitors the welding state of the projection nut 9 in real time, accurately detects whether it is firmly welded, effectively eliminates the problems of false welding and insufficient welding strength, and significantly improves the welding quality; and with the advantages of high flexibility and precise motion control of the robot, fine welding operations can also be completed in complex spaces, greatly improving the adaptability and efficiency of the projection resistance welding gun, with a wider application range. The nut retainer 3 and the displacement sensor 4 are modularly installed on the gun body assembly 1, which is convenient for disassembly and maintenance.

[0025] In this embodiment, the nut retainer 3 is provided with a receiving hole matching the projection nut 9 for guiding the projection nut 9 to enter and be positioned on the nut retainer 3. The end of the second projection welding electrode 8 is provided with a positioning pin 10. The central axis of the positioning pin 10 coincides with the central axis of the receiving hole, and the positioning pin 10 is used to position the projection nut 9 entering the receiving hole.

[0026] The integrated robot servo projection spot welding gun provided in this embodiment can achieve the following technical effects: The first projection spot welding electrode 7 and the second projection spot welding electrode 8 are coaxially arranged, ensuring the formation of high-quality welding connection points on the workpiece during the welding process, and effectively guaranteeing the accuracy of the welding pressure and position.

[0027] In this embodiment, when the resistance welding gun is aligned with the workpiece, the second projection spot welding electrode 8 abuts against the workpiece, and the displacement sensor 4 is used to detect the alignment situation between the electrode arm 2 and the welding reserved hole on the workpiece; Alternatively, after the resistance welding gun performs the welding operation, the second projection spot welding electrode 8 abuts against the workpiece and the projection nut 9, and the displacement sensor 4 is used to detect the welding quality of the projection nut 9.

[0028] In this embodiment, a cooling water pipe 11 is arranged on the outer side of the electrode arm 2, and the cooling water pipe 11 is connected to a cooling circulation device; It further includes a first flexible connector 12 and a second flexible connector 13. The first flexible connector 12 is connected between the first projection spot welding electrode 7 and the transformer 6, and the second flexible connector 13 is connected between the electrode arm 2 and the transformer 6, so that an energized circuit is formed when the first projection spot welding electrode 7 and the second projection spot welding electrode 8 abut against the welding point of the projection nut 9 against the workpiece.

[0029] It can be understood that in this embodiment, a cooling water pipe 11 is arranged on the outer side of the electrode arm 2, and the cooling water pipe 11 is connected to the cooling circulation device through a cooling water distribution block; wherein, a water pipe path limiting groove is provided along the surface of the electrode arm 2, so that the cooling water pipe 11 is embedded on the surface of the electrode arm 2; and, in this embodiment, the transformer 6 is arranged under the gun body assembly 1 to output current to the electrode arm 2, and the first flexible connector 12 and the second flexible connector 13 are respectively connected between the first projection spot welding electrode 7 and the transformer 6, and the electrode arm 2 and the transformer 6.

[0030] The integrated robot servo projection spot welding gun provided in this embodiment can achieve the following technical effects: The transformer 6 provides current for the first projection spot welding electrode 7 and the second projection spot welding electrode 8 respectively through the first flexible connector 12 and the second flexible connector 13 to form an energized circuit, so as to ensure that an energized circuit is formed after the projection nut 9 abuts against the welding point of the workpiece and then is energized, thereby realizing the automation and precision of the welding process.

[0031] Embodiment 2 Please refer to Figure 5, in this embodiment, a monitoring method is also provided, which can be used for any one of the integrated robot servo projection spot welding guns in the above-mentioned Embodiment 1. An encoder is provided in the drive motor of the integrated robot servo projection spot welding gun, and at least a Hall sensor and a temperature sensor are provided in the electrode arm of the integrated robot servo projection spot welding gun. The encoder, the Hall sensor and the temperature sensor are electrically connected to the fault diagnosis and analysis device; the monitoring method includes: S10. Obtain the displacement data of the first projection welding electrode through the encoder; S20. Obtain the real-time current and voltage data in the electrode arm through the Hall sensor; S30. Obtain the real-time temperature data of the electrode arm and the cooling water pipeline through the temperature sensor; S40. Take the displacement data, the real-time current and voltage data, and the real-time temperature data as welding parameters. The welding parameters are input into the fault diagnosis and analysis device, and the operating state of the device is analyzed through a fault diagnosis algorithm. If the operating state of the device is abnormal, an abnormal alarm signal is generated in real time, and corresponding alarm action instructions are triggered according to the alarm level.

[0032] It can be understood that the displacement of the first projection welding electrode 7 is accurately measured by using the encoder of the drive motor 5 to track the movement trajectory and position change of the electrode; and the current and voltage data in the electrode arm 2 are obtained in real time by means of the Hall sensor to reflect the electrical characteristics during the welding process; at the same time, the temperature information of the electrode arm 2 and the cooling water pipeline 11 is collected in real time through the temperature sensor to monitor the thermal state of the device. The above real-time data are used as welding parameters and input into the fault diagnosis algorithm for analysis. The algorithm judges whether the operating state of the device is normal according to the preset model and threshold. If an abnormality is detected, the system will immediately generate an alarm signal and trigger corresponding action instructions according to the severity of the alarm, such as recording data, prompting the operator, adjusting welding parameters or performing an emergency stop, etc.

[0033] Please refer to Figure 6 , in this embodiment, it further includes: S101. Before a welding, detect the contact depth between the positioning pin on the electrode arm and the workpiece guide hole through the displacement sensor arranged at the end of the second projection welding electrode. If the depth does not reach the set value, it is determined that the alignment is abnormal; S102. After a welding, detect the rebound displacement of the projection nut after welding with the workpiece through the displacement sensor. If the rebound displacement is less than the preset value, it is determined that the formation of the welding nugget is incomplete, and a secondary welding process is triggered.

[0034] Understandably, when the robotic servo projection spot welding gun of this embodiment is aligned with the workpiece, the contact depth between the positioning pin 10 on the electrode arm 2 and the workpiece guiding hole is detected by the displacement sensor 4 provided at the end of the second projection welding electrode 8, so as to determine whether the alignment is abnormal; when the robotic servo projection spot welding gun of this embodiment completes the alignment of the projection nut 9 and the workpiece, the springback displacement after welding the projection nut 9 and the workpiece is detected. If the springback displacement is less than the preset value, it is determined that the formation of the welding nugget is incomplete and the secondary welding process is triggered to ensure the welding quality.

[0035] Understandably, the secondary welding process is to perform a welding action on the welding point where the formation of the butt fusion nucleus is incomplete again after it is determined to be incomplete; if the formation of the welding nugget is still incomplete after the secondary welding, mark this welding point as an abnormal welding point (facilitating the staff to track through the mark and arrange for abnormal handling, such as appearance inspection or destructive inspection, so as to physically isolate the defective workpieces and analyze the cause of the abnormality), and continue the projection spot welding operation of the next welding point or the next workpiece.

[0036] Please refer to Figure 7 , in this embodiment, the welding parameters are input into the fault diagnosis and analysis device, and the analysis of the equipment operation status through the fault diagnosis algorithm includes: S401. Compare the displacement data with the preset motion trajectory to obtain displacement deviation data, and calculate displacement accuracy standard deviation data based on the displacement deviation data; S402. Compare and calculate the real-time current and voltage data with the preset threshold range to obtain the current and voltage volatility; S403. Compare and calculate the real-time temperature data with the preset temperature curve to obtain the electrode temperature rise data; S404. Analyze the displacement accuracy standard deviation data, the current and voltage volatility, and the electrode temperature rise data, and output the analysis result of the equipment operation status.

[0037] Understandably, the following technical effects can be achieved in this embodiment: 1. By comparing the displacement data with the preset motion trajectory, the current and voltage data with the preset threshold range, and the temperature data with the preset temperature curve, the displacement accuracy standard deviation, the current and voltage volatility, and the electrode temperature rise data are calculated. The analysis of these parameters can accurately identify abnormal conditions during equipment operation, timely discover and solve welding quality problems, and improve the strength and stability of the welding points.

[0038] In this embodiment, the alarm level triggers the alarm action instruction, including: first-level alarm, when there is an instantaneous overlimit in the welding parameters, trigger the controller of the robot main body to record the deviation data, and the instantaneous overlimit is that the overlimit amplitude exceeds 10% of the rated value and the duration reaches 0.5 seconds; Secondary alarm: When the number of times that the welding parameters instantaneously exceed the limit within the same welding cycle exceeds the preset value, the controller of the robot main body is triggered to extend the welding interval by 2 seconds and display a warning icon through the HMI interface to prompt the operator to check; Tertiary alarm: When the first projection welding electrode has no displacement change during the operation of the drive motor in the non-welding state, or the current drops suddenly by more than 20% of the rated value or the temperature rise rate of the electrode arm exceeds 30% of the rated value during the welding state, the controller of the robot main body is triggered to output an emergency stop signal and execute it to cut off the power supply of the transformer, close the brake of the drive motor, and send an emergency stop alarm to the control center through the Ethernet.

[0039] Understandably, the following technical effects can be achieved in this embodiment: 1. It can trigger corresponding alarm action instructions according to the alarm level, such as recording data, prompting the operator to check, extending the welding interval, executing an emergency stop, etc., which helps to handle abnormal situations in a timely manner, reduce the equipment downtime, and send early warnings to the control center through the HMI interface and the Ethernet, facilitating preventive maintenance by maintenance personnel in advance and reducing the maintenance cost.

[0040] Embodiment 3 In one embodiment of the present invention, a unique quality code is generated for each welding point according to the position, time, and process parameters of the welding point, and the quality code is associated and stored with the original data and analysis results of the displacement data, current-voltage volatility, and electrode temperature rise data corresponding to the welding point in the database.

[0041] In this embodiment, by generating a unique quality code for each welding point and associating and storing various data during the welding process, the traceability of the welding quality is realized.

[0042] In this embodiment, it further includes: analyzing the trend of batch welding data based on the quality code through a machine learning model. The machine learning model is a supervised learning model trained by historical welding data, and its input features include the displacement data, current-voltage volatility, electrode temperature rise data, and analysis results associated with the quality code, and the output is the predicted value of the electrode life and the predicted value of the degradation of the transformer performance; specifically including: Calculating the positioning repeat accuracy of the electrode. If the standard deviation of the positioning accuracy increases by more than 0.1 cm in several consecutive weldings, prompt through the HMI interface that the electrode needs to be maintained and send an early warning to the control center through the Ethernet; Calculating the output power attenuation trend of the transformer 6. If the power attenuation exceeds 5% in several consecutive weldings, prompt through the HMI interface that the transformer 6 needs to be maintained and send an early warning to the control center through the Ethernet.

[0043] Understandably, the positioning repeatability accuracy of the welding electrode is an important indicator to measure whether the electrode can accurately return to the predetermined position during multiple welding processes. An increase in the standard deviation of the positioning accuracy exceeding 0.1 cm indicates a relatively obvious decline in the positioning accuracy of the electrode, which may lead to welding position deviation and affect the quality and strength of the solder joints. When the standard deviation of the positioning accuracy increases by more than 0.1 cm during several consecutive welds, the operator is prompted through the HMI interface to maintain the electrode, and a warning is sent to the control center via Ethernet, facilitating the arrangement of maintenance personnel to inspect, adjust, or replace the electrode, avoiding more welding quality problems caused by the continuous decline of the electrode positioning accuracy, contributing to ensuring the normal progress of subsequent welding work, and improving the stability of product quality.

[0044] And understandably, the output power is a key performance indicator of the transformer 6, which is directly related to the amount of energy that can be provided during welding; a power attenuation exceeding 5% during several consecutive welds means that the performance of the transformer 6 has degraded significantly, which may cause parameters such as welding current and voltage to fail to meet the ideal welding process requirements, affecting welding quality, and even defects such as poor welding may occur. Prompting the maintenance of the transformer 6 through the HMI interface and sending a warning to the control center can enable the maintenance personnel to know the performance status of the transformer 6 in a timely manner, and perform maintenance on the transformer 6 in a timely manner, such as checking whether the windings are damaged and whether there are problems such as poor contact, and taking corresponding repair measures to prevent the further deterioration of the performance of the transformer 6 and ensure the normal operation of the welding equipment.

[0045] The monitoring method for the integrated robot servo projection spot welding gun provided in this embodiment can achieve the following technical effects: By summarizing and analyzing batch data, the changing trends of various indicators during the welding process over time or the number of welds can be observed more clearly, and thus the electrode life and the performance degradation of the transformer 6 can be predicted more accurately, which helps to plan the equipment maintenance plan in advance, reasonably arrange production tasks, and avoid production interruptions caused by sudden equipment failures.

[0046] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structural transformation made under the inventive concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied to other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. An integrated robot servo bump welding gun, characterized in that: include: A robot body, a gun body assembly (1), an electrode arm (2), a nut holder (3) and a displacement sensor (4); The gun body assembly (1) is arranged on the robot body, and the robot body is configured to drive the gun body assembly (1) to move within a processing station; The gun body assembly (1) is also provided with a driving motor (5) and a transformer (6); a driving end of the driving motor (5) is provided with a first convex spot welding electrode (7); and the nut retainer (3) is provided at the end of the first convex spot welding electrode (7); The electrode arm (2) is arranged on the lower side of the gun body assembly (1), and the electrode arm (2) is electrically connected to the transformer (6); The electrode arm (2) is provided with a second convex spot welding electrode (8), the end of the first convex spot welding electrode (7) is coaxially arranged with the second convex spot welding electrode (8), and the displacement sensor (4) is arranged at the end of the second convex spot welding electrode (8); The driving motor (5), the transformer (6) and the displacement sensor (4) are all electrically connected to the robot body.

2. The integrated robot servo bump welding gun according to claim 1, characterized in that: The nut holder (3) is provided with a receiving hole matching the raised point nut (9) and used for guiding the raised point nut (9) to enter and be positioned on the nut holder (3); A positioning pin (10) is provided at the end of the second convex spot welding electrode (8), the central axis of the positioning pin (10) coincides with the central axis of the receiving hole, and the positioning pin (10) is used to position the convex spot nut (9) entering the receiving hole; Wherein, when the resistance welding gun is aligned with the workpiece, the second convex spot welding electrode (8) abuts against the workpiece, and the displacement sensor (4) is used to detect the alignment of the electrode arm (2) and the welding reserved hole on the workpiece; Alternatively, after the resistance welding gun welding operation, the second convex spot welding electrode (8) abuts against the workpiece and the convex spot nut (9), and the displacement sensor (4) is used to detect the welding quality of the convex spot nut (9).

3. A monitoring method, characterized in that: The integrated robot servo bump welding gun can be used as described in any one of claims 1 to 2, wherein an encoder is provided in the driving motor of the integrated robot servo bump welding gun, and at least a Hall sensor and a temperature sensor are provided in the electrode arm of the integrated robot servo bump welding gun, and the encoder, the Hall sensor and the temperature sensor are electrically connected to a fault diagnosis and analysis device; the monitoring method comprises: Acquiring displacement data of the first bump welding electrode by means of the encoder; Acquiring real-time current and voltage data in the electrode arm through the Hall sensor; Acquiring real-time temperature data of the electrode arm and the cooling water pipeline through the temperature sensor; The displacement data, the real-time current and voltage data, and the real-time temperature data are used as welding parameters, and the welding parameters are input into the fault diagnosis and analysis device. The equipment operation status is analyzed by a fault diagnosis algorithm. If the equipment operation status is abnormal, an abnormal alarm signal is generated in real time, and a corresponding alarm action instruction is triggered according to the alarm level.

4. The monitoring method according to claim 3, characterized in that: Also includes: Before welding once, the contact depth between the positioning pin on the electrode arm and the guide hole of the workpiece is detected by a displacement sensor arranged at the end of the second convex spot welding electrode. If the depth does not reach the set value, it is determined that the alignment is abnormal. And / or, after one welding, the springback displacement after welding of the convex nut and the workpiece is detected by a displacement sensor. If the springback displacement is less than a preset value, it is determined that the welding nugget is not completely formed, and a secondary welding process is triggered.

5. The monitoring method according to claim 3, characterized in that: The welding parameters are input into the fault diagnosis and analysis device, and the operating status of the device is analyzed by the fault diagnosis algorithm, including: Comparing the displacement data with a preset motion trajectory to obtain displacement deviation data, and calculating displacement accuracy standard deviation data based on the displacement deviation data; Compare and calculate the real-time current and voltage data with a preset threshold range to obtain a current and voltage fluctuation rate; Compare and calculate the real-time temperature data with the preset temperature curve to obtain the electrode temperature rise data; The displacement accuracy standard deviation data, the current and voltage fluctuation rate, and the electrode temperature rise data are analyzed and output as equipment operation status analysis results.

6. The monitoring method according to claim 3, characterized in that: The alarm action instruction triggered by the alarm level includes: Level 1 alarm: an instantaneous over-limit occurs in the welding parameters, triggering the controller of the robot body to record the deviation data. The instantaneous over-limit refers to an over-limit amplitude exceeding 10% of the rated value and lasting for 0.5 seconds.

7. The monitoring method according to claim 3, characterized in that: The alarm action instructions triggered by the alarm level include: a level 2 alarm, in the same welding cycle, the number of times the welding parameters exceed the limit instantaneously exceeds the preset value, triggering the controller of the robot body to extend the welding interval by 2 seconds and displaying a warning icon through the HMI interface to prompt the operator to check.

8. The monitoring method according to claim 3, characterized in that: The alarm action instructions triggered by the alarm levels include: level three alarm, when the drive motor is running in the non-welding state, there is no displacement change of the first convex spot welding electrode, when the welding state, the current drops sharply by more than 20% of the rated value, or the temperature rise rate of the electrode arm exceeds 30% of the rated value, the controller of the robot body is triggered to output an emergency stop signal and execute it to cut off the power supply of the transformer, close the drive motor brake, and send an emergency stop alarm to the control center via Ethernet.

9. The monitoring method according to claim 5, characterized in that: A unique quality code is generated for each welding point according to the position, time and process parameters of the welding point. The quality code is associated with and stores the original data of displacement data, current and voltage fluctuation rate, electrode temperature rise data corresponding to the welding point and the analysis results in the database.

10. The monitoring method according to claim 9, characterized in that: Also includes: The trend of batch welding data is analyzed based on quality coding through a machine learning model. The machine learning model is a supervised learning model trained with historical welding data. Its input features include displacement data associated with quality coding, current and voltage fluctuation rate, electrode temperature rise data and analysis results. The output is the predicted value of electrode life and transformer performance degradation. Specifically, it includes: Calculate the positioning repeatability of the electrode. If the standard deviation of the positioning accuracy increases by more than 0.1cm during several consecutive welding operations, the HMI interface will prompt that the electrode needs to be maintained and send an early warning to the control center via Ethernet. Calculate the output power attenuation trend of the transformer. If the power attenuation exceeds 5% during several consecutive welding operations, the HMI interface will prompt that the transformer needs maintenance and send an early warning to the control center via Ethernet.

Images