Integrated Robot Servo Projection Spot Welding Gun and Monitoring Method

Abstract

The present invention belongs to the technical field of welding production, and specifically 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 holder and a displacement sensor; the gun body assembly is arranged on a robot body, and a drive motor and a transformer are respectively arranged on the upper and lower sides, the drive end of the drive motor is provided with a first bump welding electrode, and the nut holder is arranged at the end of the first bump welding electrode; the electrode arm is arranged on the lower side of the gun body assembly and is electrically connected to the transformer; the electrode arm is provided with a second bump welding electrode; the drive motor, the transformer and the displacement sensor are all electrically connected to the robot body; the present invention can adapt to bump welding of different workpieces, monitor parameters of the welding process in real time and compare and analyze them with preset parameters, promptly discover and solve welding quality problems, warn of potential faults in advance, and reduce equipment downtime and maintenance costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of welding production, in particular to the field of projection welding, and in particular to an integrated robot servo projection 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, bump welding technology has gradually become an important breakthrough direction in the field of welding: bump welding is a special resistance spot welding method, which processes bumps on the contact surface of the weldment. When current passes through, the bumps have large resistance and high current density, and they are quickly heated and melted to form welds.

[0003] Existing fixed spot welding guns have some obvious shortcomings in practical applications: first, their flexibility is severely limited, and their fixed position and angle make them only suitable for welding workpieces of specific shapes and positions. Once the design or production process of the weldment changes, the spot welding gun often needs to be redesigned and reinstalled, which makes adjustments difficult and costly. Second, fixed spot welding guns have high maintenance costs. Due to their relatively complex structure, key components such as electrodes and transformers are prone to wear and failure after long-term use. Maintenance is difficult and time-consuming, which will lead to production interruptions and increase the company's downtime costs. Summary of the Invention

[0004] In order to overcome the shortcomings of the existing technology, the present invention provides an integrated robot servo spot welding gun and a monitoring method to solve the problems that the flexibility of the fixed spot welding gun in the existing technology is severely limited. Once the design or production process of the weldment changes, it is often necessary to redesign and reinstall the spot welding gun, which is difficult and costly to adjust; key components such as electrodes and transformers are prone to wear and failure, and maintenance is difficult and time-consuming.

[0005] One solution of the present invention provides an integrated robot servo bump welding gun, comprising: a robot body, a gun body assembly, an electrode arm, a nut holder, and a displacement sensor;

[0006] The gun body assembly is arranged on the robot body, and the robot body is configured to drive the gun body assembly to move within the processing station;

[0007] 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 convex spot welding electrode, and the nut retainer is provided at the end of the first convex spot welding electrode;

[0008] The electrode arm is arranged on the lower side of the gun body assembly, and the electrode arm is electrically connected to the transformer;

[0009] The electrode arm is provided with a second convex spot welding electrode, the end of the first convex spot welding electrode is coaxially arranged with the second convex spot welding electrode, and the displacement sensor is arranged at the end of the second convex spot welding electrode;

[0010] The driving motor, the transformer and the displacement sensor are all electrically connected to the robot body.

[0011] In one embodiment of the present invention, the nut holder is provided with a receiving hole matching the raised point nut, for guiding the raised point nut to enter and be positioned on the nut holder;

[0012] A positioning pin is provided at the end of the second convex spot welding electrode, the central axis of the positioning pin coincides with the central axis of the accommodating hole, and the positioning pin is used to position the convex spot nut entering the accommodating hole;

[0013] Wherein, when the resistance welding gun is aligned with the workpiece, the second convex spot welding electrode abuts against the workpiece, and the displacement sensor is used to detect the alignment of the electrode arm and the welding reserved hole on the workpiece;

[0014] Alternatively, after the resistance welding gun welding operation, the second bump welding electrode abuts against the workpiece and the bump nut, and the displacement sensor is used to detect the welding quality of the bump nut.

[0015] In one embodiment of the present invention, a monitoring method is further provided, which can be used for the integrated robot servo bump welding gun described in any one of the above embodiments, wherein the drive motor of the integrated robot servo bump welding gun is provided with an encoder, and the electrode arm of the integrated robot servo bump welding gun is provided with at least a Hall sensor and a temperature sensor, and the encoder, the Hall sensor, and the temperature sensor are electrically connected to a fault diagnosis and analysis device; the monitoring method comprises:

[0016] Acquiring displacement data of the first bump welding electrode through the encoder;

[0017] Acquiring real-time current and voltage data in the electrode arm through the Hall sensor;

[0018] Acquiring real-time temperature data of the electrode arm and the cooling water pipeline through the temperature sensor;

[0019] 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 through 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.

[0020] In one embodiment of the present invention, the present invention further comprises:

[0021] Before a welding operation, a displacement sensor at the end of the second bump welding electrode detects the contact depth between the positioning pin on the electrode arm and the guide hole of the workpiece. If the depth does not reach the set value, it is determined that the alignment is abnormal.

[0022] Alternatively, after one welding operation, the springback displacement of the convex nut and the workpiece after welding is detected by a displacement sensor. If the springback displacement is less than a preset value, it is determined that the weld nugget is not formed completely, and a secondary welding process is triggered.

[0023] In one embodiment of the present invention, the welding parameters are input into the fault diagnosis and analysis device, and the analysis of the equipment operating status by the fault diagnosis algorithm includes:

[0024] 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;

[0025] Comparing and calculating the real-time current and voltage data with a preset threshold range to obtain a current and voltage fluctuation rate;

[0026] Comparing and calculating the real-time temperature data with a preset temperature curve to obtain electrode temperature rise data;

[0027] The displacement accuracy standard deviation data, the current and voltage fluctuation rates, and the electrode temperature rise data are analyzed and output as equipment operation status analysis results.

[0028] In one embodiment of the present invention, the alarm level triggering the alarm action instruction includes:

[0029] Level 1 alarm: a momentary over-limit occurs in the welding parameters, triggering the controller of the robot body to record the deviation data. The momentary over-limit refers to an over-limit amplitude exceeding 10% of the rated value and lasting for 0.5 seconds.

[0030] In one embodiment of the present invention, the alarm level triggering the alarm action instruction includes:

[0031] Level 2 alarm: If the number of instantaneous exceeding of the limit of welding parameters exceeds the preset value in the same welding cycle, the controller of the robot body will be triggered to extend the welding interval by 2 seconds and a warning icon will be displayed through the HMI interface to prompt the operator to check.

[0032] In one embodiment of the present invention, the alarm level triggering the alarm action instruction includes:

[0033] In the third level alarm, when the driving motor is running in the non-welding state, there is no displacement change of the first convex spot welding electrode, the current drops sharply by more than 20% of the rated value in the welding state, 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 driving motor brake, and send an emergency stop alarm to the control center via Ethernet.

[0034] In one of the solutions of the present invention, a unique quality code is generated for each welding point based on the position, time, and process parameters of the welding point. The quality code is associated with and stores the original data of the displacement data, current and voltage fluctuation rate, and electrode temperature rise data corresponding to the welding point and the analysis results in a database.

[0035] In one embodiment of the present invention, the trend of batch welding data is analyzed based on the quality code using a machine learning model. The machine learning model is a supervised learning model trained with historical welding data. The input features of the machine learning model include displacement data associated with the quality code, current and voltage fluctuation rates, electrode temperature rise data, and analysis results. The output is a predicted value of electrode life and a predicted value of transformer performance degradation. Specifically, the model includes:

[0036] Calculate the positioning repeatability of the electrode. If the standard deviation of the positioning accuracy increases by more than 0.1cm during several consecutive welds, the HMI interface prompts that the electrode needs maintenance and sends an early warning to the control center via Ethernet.

[0037] Calculate the transformer's output power attenuation trend. If the power attenuation exceeds 5% during several consecutive welding cycles, the HMI interface prompts that the transformer needs maintenance and sends an early warning to the control center via Ethernet.

[0038] The integrated robot servo bump welding gun and monitoring method provided by the present invention can achieve the following technical effects:

[0039] 1. The integrated structural design of the robot body and the bump welding gun ensures the stability and accuracy of their collaborative work. The robot body drives the movement of the gun assembly, and cooperates with components such as the drive motor, transformer and displacement sensor. The displacement sensor can accurately detect the alignment of the electrode arm and the workpiece, as well as the welding quality of the bump nut, to ensure the accuracy and reliability of welding. The robot servo bump welding gun can better adapt to the bump welding of different workpieces through multi-axis movement. Compared with conventional fixed bump welding equipment, it reduces adjustment time and improves production efficiency.

[0040] 2. By real-time monitoring of displacement data, current, voltage 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, thereby improving the strength and stability of the welding points.

[0041] 3. By generating a unique quality code for each welding point and associating and storing various data in the welding process, the traceability of welding quality is achieved. By analyzing the trend of batch welding data based on machine learning models, it is possible to predict electrode life and transformer performance degradation, and provide early warning of potential failures, allowing maintenance personnel to perform preventive maintenance in a timely manner, reducing equipment downtime and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0043] Figure 1 A schematic diagram showing the structure of the integrated robot servo bump welding gun of the present invention;

[0044] Figure 2 A schematic diagram showing the internal structure of the integrated robot servo bump welding gun of the present invention;

[0045] Figure 3 A schematic diagram showing the structure of a first bump welding electrode according to the present invention;

[0046] Figure 4 A schematic structural diagram showing a second bump welding electrode of the present invention;

[0047] Figure 5 A schematic flow chart showing the monitoring method of the present invention;

[0048] Figure 6 A schematic diagram showing the operation flow of the displacement sensor of the present invention;

[0049] Figure 7 A schematic diagram showing a flow chart of equipment operating status analysis according to the present invention.

[0050] The following are the descriptions of the accompanying figures:

[0051] 1-gun body assembly; 2-electrode arm; 3-nut holder; 4-displacement sensor; 5-drive motor; 6-transformer; 7-first bump welding electrode; 8-second bump welding electrode; 9-bump nut; 10-locating pin; 11-cooling water pipe; 12-first flexible connector; 13-second flexible connector. DETAILED DESCRIPTION

[0052] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0053] Example 1

[0054] Please refer to Figure 1-Figure 4 , one embodiment of the present invention provides an integrated robot servo bump welding gun, comprising: a robot body, a gun body assembly 1, an electrode arm 2, a nut holder 3 and a displacement sensor 4;

[0055] The gun body assembly 1 is mounted on the robot body via a modular standard mounting flange, and the robot body is configured to drive the gun body assembly 1 to move within a processing station;

[0056] The gun assembly 1 is further provided with a driving motor 5 and a transformer 6. The driving end of the driving motor 5 is provided with a first convex spot welding electrode 7. The nut retainer 3 is provided at the end of the first convex spot welding electrode 7.

[0057] 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;

[0058] 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;

[0059] The driving motor 5 , the transformer 6 and the displacement sensor 4 are all electrically connected to the robot body.

[0060] It can be understood that the robot body includes a body, joints and an execution structure. The body, as the supporting part of the entire robot, has high strength and rigidity, can fix and support other components, and can accommodate some sensors, actuators and control systems inside; the joints are the core components of the robot's movement, usually composed of motors, reducers, drive shafts and gears, etc., which can control the movement of the robot's arms or wrists in multiple directions and realize various actions of the robot. Common joints have 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, which can perform complex actions such as grasping, rotating, and placing; the gun body assembly 1 is set on the execution structure through a modular standard mounting flange.

[0061] The integrated robot servo bump welding gun provided in this embodiment can achieve the following technical effects:

[0062] 1. The integrated structural design of the robot body and the bump welding gun ensures the stability and accuracy of their collaborative work. Among them, through the precise coordination of the drive motor 5, the nut holder 3 and the displacement sensor 4, the full process automation from the taking of the bump nut 9, the application of pressure to the resistance welding is realized; and the displacement sensor 4 monitors the welding status of the bump nut 9 in real time, accurately detects whether it is firmly welded, effectively eliminates the problems of cold welding and insufficient welding strength, and significantly improves the welding quality; and with the advantages of the robot's high flexibility and precise motion control, fine welding movements can be completed in complex spaces, which greatly improves the adaptability and efficiency of the bump resistance welding gun and expands its scope of application. The nut holder 3 and the displacement sensor 4 are modularly installed on the gun body assembly 1, which is convenient for disassembly and maintenance.

[0063] In this embodiment, the nut holder 3 is provided with a receiving hole matching the raised nut 9, for guiding the raised nut 9 to enter and be positioned on the nut holder 3;

[0064] A positioning pin 10 is provided at the end of the second bump welding electrode 8 , the central axis of the positioning pin 10 coincides with the central axis of the accommodating hole, and the positioning pin 10 is used to position the bump nut 9 entering the accommodating hole.

[0065] The integrated robot servo bump welding gun provided in this embodiment can achieve the following technical effects: the coaxially arranged first bump welding electrode 7 and the second bump welding electrode 8 ensure the formation of high-quality welding connection points on the workpiece during the welding process, effectively ensuring the accuracy of welding pressure and position.

[0066] In this embodiment, 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;

[0067] 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 .

[0068] In this embodiment, a cooling water pipe 11 is provided on the outside of the electrode arm 2, and the cooling water pipe 11 is connected to a cooling circulation device;

[0069] It also includes a first soft connector 12 and a second soft connector 13, wherein the first soft connector 12 is connected between the first convex spot welding electrode 7 and the transformer 6, and the second soft connector 13 is connected between the electrode arm 2 and the transformer 6, so that the first convex spot welding electrode 7 and the second convex spot welding electrode 8 form an electrical circuit when the convex spot nut 9 abuts the welding point of the workpiece.

[0070] It can be understood that in this embodiment, a cooling water pipe 11 is provided on the outside 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 in the surface of the electrode arm 2; and, in this embodiment, the transformer 6 is provided on the lower side of 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 respectively connect the first bump welding electrode 7 and the transformer 6, and the electrode arm 2 and the transformer 6.

[0071] The integrated robot servo bump welding gun provided in this embodiment can achieve the following technical effects: the transformer 6 provides current to the first bump welding electrode 7 and the second bump welding electrode 8 through the first soft connector 12 and the second soft connector 13 respectively, forming a power-on circuit to ensure that the power is turned on again at the welding point where the bump nut 9 abuts the workpiece to form a power-on circuit, thereby realizing the automation and precision of the welding process.

[0072] Example 2

[0073] Please refer to Figure 5 This embodiment further provides a monitoring method that can be used for the integrated robot servo bump welding gun described in any one of the above-mentioned embodiments 1, wherein the drive motor of the integrated robot servo bump welding gun is provided with an encoder, and the electrode arm of the integrated robot servo bump welding gun is provided with at least a Hall sensor and a temperature sensor, and the encoder, the Hall sensor, and the temperature sensor are electrically connected to a fault diagnosis and analysis device; the monitoring method comprises:

[0074] S10, obtaining displacement data of the first bump welding electrode through the encoder;

[0075] S20, acquiring real-time current and voltage data in the electrode arm through the Hall sensor;

[0076] S30, obtaining real-time temperature data of the electrode arm and the cooling water pipeline through the temperature sensor;

[0077] S40. The displacement data, the real-time current and voltage data, and the real-time temperature data are used as welding parameters. The welding parameters are input into the fault diagnosis and analysis device. The operating status of the equipment is analyzed using a fault diagnosis algorithm. If the operating status of the equipment is abnormal, an abnormal alarm signal is generated in real time, and a corresponding alarm action instruction is triggered according to the alarm level.

[0078] It can be understood that the encoder of the drive motor 5 is used to accurately measure the displacement of the first convex spot welding electrode 7 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 with the help 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 pipe 11 is collected in real time through the temperature sensor to monitor the thermal state of the equipment. The above real-time data is used as welding parameters and input into the fault diagnosis algorithm for analysis. The algorithm determines whether the equipment operation status is normal based on 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 executing an emergency stop.

[0079] Please refer to Figure 6 , in this embodiment, further comprising:

[0080] S101, before a welding operation, detecting the contact depth between the positioning pin on the electrode arm and the guide hole of the workpiece by a displacement sensor provided at the end of the second bump welding electrode, and determining that the alignment is abnormal if the depth does not reach a set value;

[0081] S102. After the first welding, the springback displacement of the convex nut and the workpiece after welding is detected by a displacement sensor. If the springback displacement is less than a preset value, it is determined that the weld nugget is not completely formed, and a second welding process is triggered.

[0082] It can be understood that when the robot servo bump welding gun of this embodiment is aligned with the workpiece, the displacement sensor 4 set at the end of the second bump welding electrode 8 detects the contact depth between the positioning pin 10 on the electrode arm 2 and the workpiece guide hole, so as to determine whether the alignment is abnormal; when the robot servo bump welding gun of this embodiment completes the alignment of the bump nut 9 with the workpiece, it detects the rebound displacement after the bump nut 9 is welded to the workpiece. If the rebound displacement is less than the preset value, it is determined that the welding nugget is incomplete and the secondary welding process is triggered to ensure the welding quality.

[0083] It can be understood that the secondary welding process is to perform welding again on the weld point with incomplete weld nugget formation after determining that it is incomplete; if the weld nugget formation is still incomplete after the secondary welding, the weld point is marked as an abnormal weld point (to facilitate the staff to track and arrange abnormal processing through marking, such as appearance inspection or destructive inspection, so as to physically isolate the defective workpiece and analyze the cause of the abnormality), and continue with the next weld point or the next workpiece convex spot welding operation.

[0084] 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 operating status by the fault diagnosis algorithm includes:

[0085] S401, 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;

[0086] S402: Compare and calculate the real-time current and voltage data with a preset threshold range to obtain a current and voltage fluctuation rate;

[0087] S403, comparing and calculating the real-time temperature data with a preset temperature curve to obtain electrode temperature rise data;

[0088] S404: Analyze the displacement accuracy standard deviation data, the current and voltage fluctuation rates, and the electrode temperature rise data, and output the result of the equipment operation status analysis.

[0089] It can be understood that this embodiment can achieve the following technical effects:

[0090] 1. By comparing displacement data with preset motion trajectories, current and voltage data with preset threshold ranges, and temperature data with preset temperature curves, we calculate the displacement accuracy standard deviation, current and voltage fluctuation rates, and electrode temperature rise data. Analysis of these parameters accurately identifies abnormalities during equipment operation, allowing for timely detection and resolution of welding quality issues, and improving weld strength and stability.

[0091] In this embodiment, the alarm level triggering the alarm action instruction includes: a level 1 alarm, in which a transient over-limit occurs in the welding parameter, triggering the controller of the robot body to record deviation data, wherein the transient over-limit is defined as an over-limit amplitude exceeding 10% of the rated value and lasting for 0.5 seconds;

[0092] Level 2 alarm: If the number of times the welding parameters exceed the limit exceeds the preset value within the same welding cycle, the robot controller will be triggered to extend the welding interval by 2 seconds and a warning icon will be displayed on the HMI interface to prompt the operator to check;

[0093] In the third level alarm, when the driving motor is running in the non-welding state, there is no displacement change of the first convex spot welding electrode, the current drops sharply by more than 20% of the rated value in the welding state, 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 driving motor brake, and send an emergency stop alarm to the control center via Ethernet.

[0094] It can be understood that this embodiment can achieve the following technical effects:

[0095] 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 emergency stop, etc., which helps to deal with abnormal situations in a timely manner and reduce equipment downtime. It also sends early warnings to the control center through the HMI interface and Ethernet, so that maintenance personnel can carry out preventive maintenance in advance and reduce maintenance costs.

[0096] Example 3

[0097] In one embodiment of the present invention, a unique quality code is generated for each welding point based on the position, time, and process parameters of the welding point. The quality code is associated with and stores the original data of the displacement data, current and voltage fluctuation rate, and electrode temperature rise data corresponding to the welding point and the analysis results in a database.

[0098] In this embodiment, a unique quality code is generated for each welding point, and various data in the welding process are stored in association, thereby achieving traceability of welding quality.

[0099] In this embodiment, the method further includes: analyzing the trend of batch welding data based on the quality code using a machine learning model, wherein the machine learning model is a supervised learning model trained with historical welding data, and its input features include displacement data associated with the quality code, current and voltage fluctuation rates, electrode temperature rise data, and analysis results, and outputs the predicted value of electrode life and transformer performance degradation; specifically, the method includes:

[0100] Calculate the positioning repeatability of the electrode. If the standard deviation of the positioning accuracy increases by more than 0.1cm during several consecutive welds, the HMI interface prompts that the electrode needs maintenance and sends an early warning to the control center via Ethernet.

[0101] The output power attenuation trend of transformer 6 is calculated. If the power attenuation exceeds 5% during several consecutive welding operations, the HMI interface prompts that transformer 6 needs maintenance and sends an early warning to the control center via Ethernet.

[0102] Understandably, calculating the positioning repeatability of the electrode is an important indicator for measuring whether the electrode can accurately return to the predetermined position during multiple welding processes. An increase in the positioning accuracy standard deviation exceeding 0.1cm indicates a significant decrease in the electrode's positioning accuracy, which may lead to welding position deviations and affect the quality and strength of the weld. When the positioning accuracy standard deviation increases by more than 0.1cm during several consecutive welds, the operator is prompted through the HMI interface to maintain the electrode, and an early warning is sent to the control center via Ethernet, facilitating the arrangement of maintenance personnel to inspect, adjust, or replace the electrode, thereby avoiding further welding quality issues caused by a continued decrease in electrode positioning accuracy. This helps ensure the normal progress of subsequent welding work and improves the stability of product quality.

[0103] Understandably, output power is a key performance indicator of transformer 6, directly related to the amount of energy it can provide during welding. A power attenuation exceeding 5% during several consecutive welds indicates significant degradation of transformer 6's performance, potentially preventing parameters such as welding current and voltage from meeting ideal welding process requirements, impacting welding quality and potentially even leading to defects such as weak welds. Prompting maintenance on transformer 6 through the HMI interface and sending early warnings to the control center allows maintenance personnel to promptly monitor the performance of transformer 6, enabling them to perform timely maintenance on transformer 6, such as checking for winding damage and poor contact, and taking appropriate repair measures to prevent further deterioration of transformer 6's performance and ensure the normal operation of the welding equipment.

[0104] The monitoring method for an integrated robot servo bump welding gun provided in this embodiment can achieve the following technical effects:

[0105] By summarizing and analyzing batch data, we can more clearly observe the changing trends of various indicators in the welding process over time or the number of welds, and thus more accurately predict the electrode life and transformer 6 performance degradation. This helps to plan equipment maintenance plans in advance, reasonably arrange production tasks, and avoid production interruptions caused by sudden equipment failures.

[0106] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention description and drawings under the inventive concept of the present invention, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A monitoring method, characterized in that: An integrated robot servo bump welding gun comprises: 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 the processing station; the gun body assembly (1) is also provided with a drive motor (5) and a transformer (6), the drive end of the drive 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 provided on the lower side of the gun body assembly (1), and the electrode arm (2) is electrically connected to the transformer (6); the end of the electrode arm (2) is provided There is 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 drive motor (5), the transformer (6) and the displacement sensor (4) are all electrically connected to the robot body, the drive motor (5) is provided with an encoder, the electrode arm (2) is provided with at least a Hall sensor and a temperature sensor, and the encoder, the Hall sensor and the temperature sensor are electrically connected to the fault diagnosis and analysis equipment; The monitoring method comprises: Acquiring displacement data of the first bump welding electrode through 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 through 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.

2. The monitoring method according to claim 1, wherein: The nut retainer (3) is provided with a receiving hole matching the raised point nut (9) for guiding the raised point nut (9) to enter and be positioned on the nut retainer (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 accommodating hole, and the positioning pin (10) is used to position the convex spot nut (9) entering the accommodating hole; 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. The monitoring method according to claim 1, wherein: Also includes: Before a welding operation, a displacement sensor at the end of the second bump welding electrode detects the contact depth between the positioning pin on the electrode arm and the guide hole of the workpiece. 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 of the raised nut and the workpiece after welding 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.

4. The monitoring method according to claim 1, wherein: Inputting the welding parameters into the fault diagnosis and analysis device and analyzing the equipment operating status using a fault diagnosis algorithm includes: 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; Comparing and calculating the real-time current and voltage data with a preset threshold range to obtain a current and voltage fluctuation rate; Comparing and calculating the real-time temperature data with a preset temperature curve to obtain electrode temperature rise data; The displacement accuracy standard deviation data, the current and voltage fluctuation rates, and the electrode temperature rise data are analyzed and output as equipment operation status analysis results.

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

6. The monitoring method according to claim 1, wherein: The alarm action instructions triggered by the alarm level include: Level 2 alarm, when the number of instantaneous exceeding of the limit of the welding parameter in the same welding cycle exceeds the preset value, the controller of the robot 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.

7. The monitoring method according to claim 1, wherein: 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, triggering the controller of the robot body 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.

8. The monitoring method according to claim 4, wherein: A unique quality code is generated for each welding point based on the position, time, and process parameters of the welding point. The quality code is associated with and stores the original data of the displacement data, current and voltage fluctuation rate, and electrode temperature rise data corresponding to the welding point, as well as the analysis results in the database.

9. The monitoring method according to claim 8, wherein: Also includes: The trend of batch welding data is analyzed based on quality coding using a machine learning model. The 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 rates, 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 welds, the HMI interface prompts that the electrode needs maintenance and sends an early warning to the control center via Ethernet. Calculate the transformer's output power attenuation trend. If the power attenuation exceeds 5% during several consecutive welding cycles, the HMI interface prompts that the transformer needs maintenance and sends an early warning to the control center via Ethernet.

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