Gantry spot welding laser measurement and self-adaptive deviation correction method and equipment

Abstract

The invention relates to the technical field of welding automation and vision measurement, in particular to a gantry spot welding laser measurement and self-adaptive deviation correction method and equipment. The method aims at solving the problem that welding spot positioning is inaccurate due to manual installation and machining errors. The method comprises the following steps: acquiring an image of a welding part through a laser tracking sensor, extracting feature points from the image by adopting a horizontal intersection method, and converting the feature points into actual three-dimensional coordinates; standard coordinates in the formula are read, deviation is calculated, and three-level state judgment is carried out; the electrode holder is automatically driven to rectify deviation or enter a man-machine cooperation exception handling process according to a judgment result; and after deviation rectification, retesting is triggered, and final welding or reprocessing is decided according to a retesting result. Equipment for realizing the method comprises a sensor unit and an integrated control cabinet which are arranged on the welding tongs. Accurate positioning and self-adaptive closed-loop deviation correction of welding spots can be achieved, and the welding quality, efficiency and automation level are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of welding automation and visual measurement technology, specifically to a laser measurement and adaptive correction method and equipment for gantry spot welding. Background Technology

[0002] In the manufacturing process of rail vehicles, spot welding of the roof and floor plates to the bottom beams is a critical process. Currently, the plates and bottom beams are usually installed manually, inevitably resulting in installation errors. Furthermore, the plates and bottom beams themselves also have certain processing errors. These accumulated errors cause deviations between the actual weld point position and the theoretical design position. Direct welding will affect weld quality and structural strength. Traditional welding position adjustments rely mainly on worker visual inspection and experience, or use fixed mechanical stops for positioning. This method suffers from low positioning accuracy, large quality fluctuations between different workpieces or batches, and low work efficiency. It also cannot automatically record and adjust data during the process, hindering quality backtracking and process optimization. While some automated welding equipment can achieve a certain degree of deviation correction, its visual measurement methods are easily affected by changes in the overall workpiece placement, resulting in insufficient stability in situations where installation itself has errors. Moreover, these systems often cannot finely classify the magnitude of deviations and lack a collaborative mechanism for operator intervention and flexible adjustments when automatic adjustments are unsatisfactory. Therefore, they struggle to function reliably in complex welding applications requiring high precision and reliability.

[0003] Therefore, there is an urgent need for a measurement method and equipment that can automatically, accurately, and reliably locate the weld point and make intelligent decisions and adaptive corrections based on deviations, in order to improve welding quality, production efficiency, and automation level. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a laser measurement and adaptive correction method and equipment for gantry spot welding, aiming to achieve high-precision, adaptive closed-loop control of the welding position, and to provide a flexible human-machine collaboration mechanism and multi-scenario application mode.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] In one aspect, the present invention provides a laser measurement and adaptive correction method for gantry spot welding, comprising the following steps: Move the welding clamp to the target welding point; Trigger laser measurement to obtain the actual three-dimensional coordinates of the weld point; Read the preset standard coordinates from the recipe; The actual three-dimensional coordinates are compared with the preset standard coordinates, and the deviation values ​​ΔX, ΔY, and ΔZ in the X, Y, and Z coordinate axes are calculated. The deviation values ​​in each coordinate axis direction are compared with the preset allowable deviation threshold and the out-of-tolerance alarm threshold to generate a three-level state judgment result, which includes a normal state, an adjustment-required state, and an abnormal state. If the judgment result is an abnormal state, then the human-machine collaborative abnormal handling process will be initiated. If the judgment result is a normal state or a state that needs adjustment, then a correction command is generated based on the deviation value to drive the welding gun to perform position compensation. After the position compensation is completed, the retest process is triggered, repeating the steps of laser measurement, deviation calculation, and three-level status judgment, and deciding whether to perform welding operation or enter the human-machine collaborative abnormal handling process based on the retest results.

[0007] Furthermore, in the step of triggering laser measurement to obtain the actual three-dimensional coordinates of the weld point, the laser measurement employs a laser image algorithm. The specific rules of the laser image algorithm are as follows: Image acquisition: The welding area is scanned by a laser tracking sensor to acquire a two-dimensional laser image of the welding part; Determine the starting point: Select a processing area in the laser two-dimensional image and identify the point with the highest gray level or height in that area as the starting point; Obtain the intersection points: Draw two horizontal lines at different heights downwards along the vertical direction from the starting point, and obtain the two intersection points of the two horizontal lines with the image outline; Fitting the characteristic line: Using the principle of point-to-point straight line, fit the characteristic line of the board through these two intersection points; Calculate feature points: Calculate the intersection points of the feature line and the horizontal line passing through the starting point to obtain the feature points; Coordinate transformation: The image coordinates of the feature points are converted into actual three-dimensional coordinates, which are used as the actual positions of the solder joints.

[0008] Furthermore, the deviation values ​​in each coordinate axis direction are compared with preset allowable deviation thresholds and out-of-tolerance alarm thresholds to generate a three-level state judgment result. The specific rules for the three-level state judgment in the step of the three-level state including normal state, adjustment-required state, and abnormal state are as follows: When the deviation values ​​in all coordinate axis directions are less than or equal to the allowable deviation threshold, it is judged to be in a normal state; When the deviation value in any coordinate axis direction is greater than the allowable deviation threshold but less than or equal to the over-tolerance alarm threshold, it is determined to be in an adjustment state; when the deviation value in any coordinate axis direction is greater than the over-tolerance alarm threshold, it is determined to be in an abnormal state.

[0009] Furthermore, the specific rules for determining whether to perform the welding operation or enter the human-machine collaborative anomaly handling process based on the retest results are as follows: When the retest result indicates that the status needs adjustment or is abnormal, the equipment will pause and trigger an alarm indication. In response to the operator's action selection, execute any of the following branches: The system receives the desired correction value input by the operator on the user correction interface, drives the welding gun to perform secondary position compensation, and then executes the retest process again. In response to the operator's mandatory confirmation command, the welding operation is performed directly without subsequent compensation.

[0010] Furthermore, the gantry spot welding laser measurement and adaptive correction method supports multiple operating modes, including: Automatic online mode: In this mode, the equipment automatically executes a closed-loop control process of measurement, retesting, and automatic correction; when the retest result is normal, the system automatically confirms the welding; when the retest result is in an adjustment state or an abnormal state, manual intervention is required. Automatic offline mode: In this mode, the device automatically performs measurement and retest functions, but does not drive the welding gun to perform automatic deviation correction; Manual mode: In this mode, the device only responds to manual commands to perform measurements and display results; all actions require manual confirmation.

[0011] Furthermore, the gantry spot welding laser measurement and adaptive correction method also includes a recipe management mechanism: multiple sets of welding recipes are pre-stored, each recipe being associated with at least one program number and weld point number, and containing corresponding standard coordinates, allowable deviation thresholds, out-of-tolerance alarm thresholds, and weld point compensation values; the recipes are divided into model recipes and welded plate beam model recipes; wherein, model recipes are used to set allowable deviation thresholds and weld point compensation values, and welded plate beam model recipes are used to set standard coordinates and whether each coordinate axis is corrected; the model recipes and welded plate beam model recipes are automatically called by the process in automatic mode, and can be freely modified by the operator in manual mode; the specific parameter values ​​of the recipes can be modified in all modes, and the modification must follow the process of "start modification, input value, save and take effect".

[0012] Furthermore, the gantry spot welding laser measurement and adaptive correction method also includes an optional manual calibration mechanism: when the equipment is working in manual or automatic mode, the operator can manually trigger the calibration process; when performing calibration, the equipment updates the actual coordinates obtained by the current weld point measurement to the standard coordinates of the point, and calculates and stores them as weld point position compensation values; the calibration mechanism is used to compensate for systematic errors generated when measuring non-planar workpieces.

[0013] Furthermore, the gantry spot welding laser measurement and adaptive correction method also includes a graded alarm mechanism, with alarm levels including: Level L1 alarm: Automatic mode status is disconnected, automatic mode process is stopped, and immediate action is required, including emergency stop triggering, vision software not started or sensor connection disconnected. Level L2 alarm: Prevents automatic mode from proceeding, including when measurement results exceed the out-of-tolerance alarm threshold; Level L3 alarm: A warning alarm that also prevents the automatic mode process from proceeding until an operator responds, including when the deviation value exceeds the allowable deviation threshold or when the external controller malfunctions.

[0014] On the other hand, the present invention also provides a gantry spot welding laser measurement and adaptive correction device for implementing the aforementioned gantry spot welding laser measurement and adaptive correction method, comprising: The sensor unit includes two laser tracking sensors fixedly mounted on the welding clamp and a power distribution cabinet that powers the laser tracking sensors. It is used to acquire the actual three-dimensional coordinates of the welding point in real time and transmit the measurement data through a wireless local area network (WLAN). The integrated control cabinet, serving as the central control and interaction platform for the system, integrates the following on its front panel: The three-color indicator light is used to visually indicate the overall working status and alarm level of the system. A WLAN access device for establishing a wireless communication link with the sensor unit; A large monitoring screen is used for global monitoring of the welding clamp and workpiece status; The physical control panel includes a power knob, a mode selection knob for switching between manual and automatic modes, a measurement button, a movement button, a confirm welding button, a reset button, and an emergency stop button. The touch screen is used for setting core parameters, displaying data, and performing touch operations. The integrated control cabinet houses an industrial computer, a programmable logic controller (PLC), a network switch, and a power supply unit. The industrial computer forms a control and decision-making unit, running visual computing software to receive and process sensor data, and execute coordinate calculation, deviation calculation, three-level state judgment, and control decision logic within the aforementioned method. The PLC forms an execution control unit, receiving decision commands from the industrial computer and driving external welding robots and welding machines to perform corresponding movement, correction, and welding actions. The network switch establishes a wired data communication network between the components within the control cabinet and externally. The power supply unit includes an air switch, a 24V DC power module, a switching power supply, and a 220V AC power socket.

[0015] Furthermore, the measurement range of the laser tracking sensor in each of the X, Y, and Z coordinate axes is not less than 200 mm, and the single-axis measurement accuracy is not worse than 0.5 mm;

[0016] Furthermore, the industrial control computer has a built-in processor, memory, dedicated graphics card, and solid-state drive;

[0017] Furthermore, the data acquisition and processing cycle of the visual computing software satisfies the following condition: the time for a single loop from data acquisition to the completion of deviation value calculation is no more than 5 milliseconds;

[0018] Furthermore, the touch screen runs human-computer interaction software, and the human-computer interaction interface it presents includes at least: The main interface dynamically displays the program number, weld point number, operation mode, detection position, measured values ​​of each coordinate axis, standard value, deviation value, and three-level status judgment results. It also provides virtual buttons for measurement and re-measurement, as well as a welding confirmation mode switching function. The calibration interface provides a manual calibration function, which is used to update the standard coordinates and generate solder joint position compensation values ​​after confirming the solder joint position. The recipe management interface is used to store, retrieve, and edit welding recipes that include standard coordinates, allowable deviation thresholds, out-of-tolerance alarm thresholds, and weld point compensation values. It supports the classification management of model recipes and welded plate beam model recipes. The user correction interface provides an interactive function to input the desired correction value and trigger secondary position compensation when the retest result is abnormal. The data recording interface is used to query historical measurement and retest data, and supports filtering by time and recording measurement values, deviation values ​​and weld point information for each coordinate axis. An interactive information interface is used to monitor the real-time communication status between various components within the system; The alarm log interface is used to centrally display and trace alarm information at all levels that occur in the system.

[0019] Compared with the prior art, the present invention discloses at least the following beneficial effects:

[0020] High-precision adaptive closed-loop control has been achieved: Through an innovative "horizontal intersection method" laser image algorithm, Chenbei Vision software can accurately extract welding feature points unaffected by overall translation from workpiece images with installation and processing errors, thereby obtaining the true three-dimensional coordinates of the weld points. Combined with a closed-loop control process of "measurement---three-level judgment---automatic correction---re-measurement---decision", the equipment can automatically identify and compensate for welding position deviations of different sizes and directions in real time, significantly improving the accuracy, consistency, and process stability of welding positioning, fundamentally reducing reliance on operator experience.

[0021] A collaborative mechanism that balances intelligence and humanization has been established: the three-level status judgment (normal, adjustment required, abnormal) and corresponding human-machine collaborative anomaly handling process designed in this invention achieve an organic integration of intelligent decision-making and manual intervention. If the result is still unsatisfactory after automatic correction, the equipment provides clear alarm indications (such as button flashing) and pauses the process. Operators can flexibly choose to perform "secondary manual correction" or "forced confirmation welding" based on the site conditions. This mechanism ensures the smooth execution of the automated process while empowering operators with the necessary decision-making authority and intervention capabilities at critical stages, effectively addressing complex and ever-changing production site conditions.

[0022] This invention offers multi-mode operation capabilities covering all scenarios: It integrates three core operating modes—"manual mode," "automatic offline mode," and "automatic online mode"—and provides convenient switching between them via physical knobs and a software interface. This allows the same equipment to seamlessly adapt to different stages, such as equipment installation and commissioning, welding program verification, and mass production. "Manual mode" facilitates maintenance and special handling; "automatic offline mode" is suitable for program simulation and parameter optimization; and "automatic online mode" ensures highly efficient automated production. This design greatly improves the equipment's versatility, utilization rate, and deployment flexibility.

[0023] The overall reliability, fault tolerance, and maintainability of the equipment are enhanced: the built-in hierarchical alarm mechanism (L1 / L2 / L3) can clearly distinguish the severity of faults and take corresponding blocking or prompting strategies to guide operators to quickly locate and handle problems. Furthermore, the integration of a large monitoring screen and a human-machine interface significantly improves the maintainability and operational reliability of the equipment. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the embodiments will be briefly described below.

[0025] Figure 1 This is a schematic diagram of the main method for laser measurement and adaptive correction of gantry spot welding provided by the present invention;

[0026] Figure 2 This is a schematic diagram of the solder joint positioning process based on the horizontal intersection method;

[0027] Figure 3 This is a schematic diagram of the three-level state judgment logic flow;

[0028] Figure 4 This is a schematic diagram of the human-machine collaborative anomaly handling process;

[0029] Figure 5 This is a schematic diagram of the assembly structure of the welding clamp and the laser tracking sensor;

[0030] Figure 6 This is a schematic diagram of the overall layout of the laser tracking sensor and the power distribution cabinet;

[0031] Figure 7 This is a schematic diagram of the external structure of the integrated control cabinet;

[0032] Figure 8 This is a schematic diagram of the internal structure of the integrated control cabinet;

[0033] In the diagram: 1. Laser tracking sensor; 2. Power distribution cabinet; 3. Three-color indicator light; 4. WLAN access device; 5. Monitoring screen; 6. Physical operation panel; 7. Touch screen display; 9. Industrial computer; 10. Programmable logic controller (PLC); 11. Network switch; 61. Power knob; 62. Mode selection knob; 63. Measurement button; 64. Movement button; 65. Confirm welding button; 66. Reset button; 67. Emergency stop button; 81. Air switch; 82. DC 24V power module; 83. Switching power supply; 84. AC 220V power socket. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] See Figures 1 to 8 This invention provides a method and equipment for laser measurement and adaptive correction of gantry spot welding.

[0036] See Figures 1 to 4 The core closed-loop control process of the method of this invention is most complete in the "automatic online mode", and the specific implementation steps are as follows:

[0037] S1. Welding clamp movement. The gantry welding robot moves the welding clamp to the vicinity of the theoretical position of the target welding point according to the pre-programmed machining program.

[0038] S2. Laser measurement to obtain the actual three-dimensional coordinates of the weld joint. A laser tracking sensor mounted on the welding clamp is triggered to scan and measure the welding area. The core of this step lies in using a laser image algorithm based on the "horizontal intersection method" to accurately calculate the three-dimensional spatial coordinates of the weld joint from the acquired two-dimensional image. The specific process is as follows: Figure 2 As shown, it includes: S21. Image Acquisition: The laser tracking sensor scans the welding area and acquires a two-dimensional laser image containing the outline of the joint between the plate and the bottom beam; S22. Determine the starting point: Select a processing region in the image that contains the expected features, and identify the point with the highest gray level or height in the region as the starting point of the algorithm; S23. Obtain the intersection points: Draw two horizontal lines at different heights vertically downwards from this starting point, and obtain the two intersection points of these two horizontal lines with the laser stripe outline (such as the edge of the board in the image); S24. Fitting characteristic lines: Using the two intersection points mentioned above, based on the principle that "two points determine a straight line", fit the characteristic lines that characterize the actual edge of the plate or bottom beam. S25. Calculate feature points: Calculate the intersection point between the feature line and the horizontal line passing through the starting point. This intersection point is a stable and unique image feature point, and its position is not affected by the overall translation of the image. S26. Coordinate Transformation: Based on the sensor calibration parameters, the image pixel coordinates of the feature points are converted into actual three-dimensional coordinates (X_act, Y_act, Z_act) in the welding clamp coordinate system, which are used as the measured positions of the welding points.

[0039] S3. Read the preset standard coordinates. From the pre-stored welding recipe, retrieve the theoretical standard coordinates (X_std, Y_std, Z_std) corresponding to the current program number and weld point number.

[0040] S4. Calculate coordinate deviations. Compare the actual 3D coordinates obtained in step S2 with the standard coordinates read in step S3, and calculate the deviation values ​​ΔX = X_act - X_std, ΔY = Y_act - Y_std, and ΔZ = Z_act - Z_std in the X, Y, and Z coordinate axes, respectively.

[0041] S5, Level 3 Status Judgment: (e.g.) Figure 3 As shown, the absolute value of the deviation of each coordinate axis is compared with two preset thresholds to generate a three-level judgment result: Permissible deviation threshold (D1): Represents the maximum acceptable deviation of the welding process; Out-of-tolerance alarm threshold (D2): Represents an unacceptable deviation (D2 > D1) that may be caused by serious misalignment, measurement abnormalities, or other reasons. Normal state: If |ΔX| ≤ D1, |ΔY| ≤ D1 and |ΔZ| ≤ D1 are all true, then the current position of the welding clamp is considered qualified; Abnormal state: If any of the values ​​of |ΔX|, |ΔY|, or |ΔZ| is greater than D2, it is considered abnormal; State adjustment required: If neither of the above two situations applies, i.e., there is a deviation greater than D1. However, if all deviations are no greater than D2, then adjustment is required. The judgment result (normal / needs adjustment / abnormal) will be displayed in real time on the main interface of the human-machine interface when it is turned on.

[0042] S6. Abnormal Status Handling. If the judgment result is an abnormal status, proceed directly to... Figure 4 The human-machine collaborative anomaly handling process is shown. In this process, the system pauses and triggers an alarm, such as an L2 level alarm for "measurement result out of tolerance". The operator needs to check the welding clamp position and can choose to temporarily disable the "whether to correct deviation" function in that direction in the recipe settings interface, or adjust the out-of-tolerance alarm threshold, and then re-trigger the measurement. If the result is still abnormal after multiple measurements, the workpiece installation or sensor obstruction needs to be checked.

[0043] S7. Normal / Adjustment Required Status Handling. If the judgment result is a normal status or an adjustment required status, a correction command is generated based on the calculated deviation values ​​(ΔX, ΔY, ΔZ) to drive the welding gun to perform the corresponding position compensation, so that the end of the welding gun is accurately aligned with the actual weld point.

[0044] S8. Retesting and Final Decision. After location compensation is completed, the retesting process is automatically triggered, i.e., steps S2 to S5 are repeated. A final decision is made based on the retest results.

[0045] If the retest result is normal, the system will automatically perform the welding operation (when the "current confirmation mode" is "automatic"), which will be indicated by the confirmation welding button 65 indicator light lighting up automatically once.

[0046] If the retest result indicates a state requiring adjustment or an abnormal state, the process will proceed to the human-machine collaborative anomaly handling procedure. At this time, the reset button 66 indicator light will flash at a frequency of 1Hz. The operator has two options: Option 1 (Manual Fine-tuning / Secondary Correction): The operator accesses the "User Correction" page through the human-machine interface. In the "Desired Correction Value" input field of the corresponding coordinate axis, a new, more refined compensation value is entered based on experience (this value must be between 0 and the out-of-tolerance alarm threshold D2), and then the move button 64 is pressed. The system will drive the welding clamp to perform secondary position compensation according to this input value, and then automatically trigger a new round of retesting process, i.e., return to step S2 of the main process; Option 2 (Forced Welding Confirmation): If the operator judges based on experience that the current position meets the welding requirements (even though the measured value is out of tolerance), they can choose not to perform secondary correction. In this case, the operator presses the flashing reset button 66 and the subsequently flashing welding confirmation button 65 in sequence. The system will skip all subsequent compensation steps and directly execute the welding operation.

[0047] To adapt to different scenarios such as debugging, verification and production, this invention has designed three working modes, which can be switched through the mode selection knob 62 on the physical operation panel 6 and the human-machine interface.

[0048] Manual Mode (knob turned left): In this mode, the device functions solely as a measuring instrument. All operations, including moving the welding clamp, triggering measurements, and confirming welding, must be performed manually via physical buttons. The system does not perform automatic correction or automatic retesting, but it can display measured values, view and modify recipes, and perform manual calibration. Suitable for equipment installation, commissioning, maintenance, and handling of special operating conditions.

[0049] Automatic Mode (turn the knob to the right, green light on): The system can automatically execute the measurement, correction, and re-measurement process. This mode is further divided into: Automatic Online Mode: This is the default and core operating state in automatic mode. The system executes the complete closed-loop control mentioned above, which includes "measurement-judgment-correction-retest-decision," to achieve fully automatic adaptive correction of welding position and welding execution. This is a key mode to ensure mass production efficiency and welding quality. Automatic Offline Mode: In automatic mode, the "offline" state can be selected via the human-machine interface. The system will automatically trigger the measurement and retest process according to the program, and display all measurement data, deviation values, and judgment results to the operator, but will not output any correction instructions to the welding gun. Suitable for offline simulation operation and process parameter verification of new welding programs.

[0050] To achieve systematic management of massive weld point parameters for different workpiece models (welded beams), the system adopts hierarchical recipe management: the system pre-stores multiple sets of welding recipes, which are managed through the "Recipe Settings" interface. Recipes are divided into model recipes and welded beam model recipes: Model recipes (20 in total) mainly set the "allowable deviation value" and "weld point compensation value"; Welded beam model recipes (10 in total) mainly set the "standard value" and "whether to correct deviation" switch for each axis. In automatic mode, the system automatically matches and calls the corresponding recipe based on the running program number and weld point number; the operator cannot modify the recipe number. In manual mode, the operator can freely select and switch recipe numbers. All specific parameter values ​​(standard value, threshold, compensation value, switch status) of all recipes can be modified in all modes, but the safe operating procedure of "start modification --- input value --- save and apply" must be followed to prevent data loss due to accidental operation.

[0051] The system offers an optional manual-triggered dynamic calibration function: in either manual or automatic mode, operators can perform manual calibration through the "Calibration Measurement" interface. During calibration, the system updates the actual coordinates of the current weld point measurement to the standard coordinates of that point and automatically calculates and stores the "weld point position compensation value." This function is primarily used to compensate for systematic deviations caused by workpiece non-planarity or long-term use. The calibration process must be completed by clicking "Modify," "Manual Calibration," and "Save" in sequence.

[0052] The system has comprehensive tiered alarm and notification functions, indicated by three-color indicator lights and a user interface:

[0053] Level L1 alarm (red, highest level): Includes serious faults such as the emergency stop button being pressed, the vision computing software not starting, or the sensor network connection being disconnected. This type of alarm will immediately disconnect the system from automatic mode, and the system can only resume operation after operator intervention and reset.

[0054] Level L2 alarm (white): This mainly refers to "measurement result out of tolerance," meaning the measurement deviation exceeds the "out-of-tolerance alarm threshold (D2)" set in the recipe. This type of alarm will prevent the automated process from continuing and requires the operator to check the workpiece positioning, sensor status, or adjust the alarm threshold.

[0055] Level L3 alarms (green): These include alarms such as "Exceeded the allowable deviation value, please press the reset button," "A value has been entered in the expected deviation value, please click to move," and abnormal mode of the external controller (e.g., 840D). These alarms mainly serve as a notification and will also stop the process until the operator presses the reset button, clicks to move, or waits for it to automatically recover (e.g., the external controller recovers).

[0056] All alarm information is automatically recorded by the system and can be queried by time and level through the "Alarm Records" interface, providing a basis for fault analysis and production management.

[0057] This invention also provides a gantry spot welding laser measurement and adaptive correction device for implementing the above method. The device mainly consists of two parts: a sensor unit and an integrated control cabinet.

[0058] Sensor unit: such as Figure 5 and Figure 6 As shown, the sensing component of the system, responsible for acquiring the spatial position information of the weld joint, includes two laser tracking sensors 1 fixedly mounted on the welding clamp and a power distribution cabinet 2 for powering the sensors. The sensors are responsible for acquiring laser image data of the weld joint area in real time and transmitting the measurement data to the integrated control cabinet via a wireless local area network (WLAN). The measurement range of the sensors in each coordinate axis direction is no less than 200 mm, and the single-axis measurement accuracy is better than 0.5 mm.

[0059] Integrated control cabinet: As the control core and interaction center of the system, it integrates all key functions such as data processing, logic control, status indication, and human-machine interaction. Its appearance is as follows: Figure 7 As shown, the internal structure is as follows Figure 8 As shown.

[0060] At the top of the front panel of the integrated control cabinet is a three-color indicator light 3, which can intuitively indicate the overall working status of the system and the real-time alarm level. To its right is a WLAN access device 4, responsible for establishing and maintaining a stable wireless local area network communication link with the laser tracking sensor 1 installed on the welding gun, ensuring the real-time and reliable transmission of measurement data. The large monitoring screen 5 located in the middle of the cabinet is used for macroscopic monitoring of the overall operating status of the welding robot, welding gun, and workpiece.

[0061] The physical operation panel and touch screen display 7 are centrally located at the lower front of the integrated control cabinet, forming the core human-machine interface area. The physical operation panel 6 integrates physical control units for several key functions, including a power knob 61 for system power-on, a mode selection knob 62 for switching between manual and automatic modes, a measurement button 63 for triggering a single measurement, a movement button 64 for driving the welding clamp during user correction processes, a confirmation welding button 65 for final confirmation of welding execution, a reset button 66 for resetting alarms or specific processes, and an emergency stop button 67 for disconnection in emergency situations. Below the physical operation panel 6 is the touch screen display 7, which runs the human-machine interface software (SIMATIC WinCC RT) providing the following core interface:

[0062] The main startup interface, serving as the default working view, dynamically integrates and displays: the currently executing program number, weld point number, weld plate beam type, operation mode (manual / automatic, offline / online), and detection position (left / right); it displays in real time the actual measured values, preset standard values, calculated real-time deviation values, and the final three-level status judgment results (normal, position needs adjustment, result abnormal); this interface also provides virtual measurement and retest touch buttons, where the measurement button is available in all modes, and the retest button is only active in automatic mode; the interface integrates the PLC10 automatic mode program number display area, as well as a "current confirmation mode" switching control for setting the welding confirmation method (automatic / manual).

[0063] The calibration interface provides a manually triggered dynamic calibration function. This interface displays the program number, solder joint number, and real-time measurement data of the target solder joint, and includes dedicated interactive controls for "Modify," "Manual Calibration," and "Save." Operators must sequentially trigger "Modify," confirm the location, click "Manual Calibration" to perform calculations, and finally click "Save" for the calibration data to take effect and the solder joint compensation value to be updated. Operation data that does not complete this entire process will not be stored.

[0064] The recipe management interface is used for the systematic storage and management of welding parameters. This interface supports viewing and editing two types of recipes: "Model Recipes" (used to manage allowable deviation thresholds and weld point compensation values) and "Welded Plate Beam Model Recipes" (used to manage the standard coordinates of each weld point and the on / off switch for each axis correction). The interface provides display and editing access for recipe number, name, and specific values, and enforces a data modification process of "clicking 'Modify' first, then entering the value, and finally clicking 'Save'" to take effect. In automatic mode, the recipe number is automatically retrieved by the system and cannot be manually changed.

[0065] The user correction interface allows operators to perform manual fine-tuning when the system pauses due to abnormal retest results (requiring adjustment or in an abnormal state). This interface displays the current deviation value and total deviation value for each coordinate axis, and provides an input box for entering the "desired correction value" and a move button 64 to trigger execution. Clicking the move button initiates secondary position compensation for the welding clamp, and automatically triggers a new round of retesting upon completion of the action.

[0066] The data logging interface is used for querying and analyzing historical data. This interface displays all measurement and retest records in chronological order. Each record includes the weld point number, program name, measurement time, measurement values ​​and deviations for each of the XYZ axes, and the weld point location. The interface provides filtering functionality by time range and can distinguish between adjacent "measurement results" and "retest results."

[0067] An interactive information interface is used to monitor the internal communication status of the system in real time.

[0068] The alarm log interface is used for centralized management and tracing of system alarm events. This interface displays all alarm information categorized or in chronological order, including alarm content, level (L1, L2, L3, usually distinguished by red, white, and green), and occurrence and recovery times. It supports viewing "short-term records" and "long-term records" and provides interactive logic for confirming and clearing recovered alarms via a reset button.

[0069] Open the control cabinet, its internal structure is as follows Figure 8As shown, the system integrates its core hardware components. The central control and decision-making unit is handled by a high-performance industrial PC 9, which runs Chenbei Vision visual computing software. This PC receives sensor data, performs image processing, coordinate calculation, deviation analysis, three-level state judgment, and generates the final control decision. The time from data acquisition to deviation value calculation in a single cycle is controlled within 5 milliseconds. The logic execution control unit is handled by a programmable logic controller (PLC) 10, which receives instructions from the industrial PC 9 and precisely drives the external welding robot and welding machine to perform specific actions such as movement, deviation correction, and welding. The network switch 11 is responsible for establishing wired data communication networks between the industrial PC 9, the PLC 10, and other components within the cabinet, as well as with external connections. The system's power supply is guaranteed by a complete power supply system, including a main air switch 81, a 24V DC power module 82 for powering the control circuit, a switching power supply 83 for powering the industrial PC and other equipment, and a 220V AC power socket 84 providing external interfaces.

[0070] The specific configuration of the equipment is as follows:

[0071] Laser tracking sensor 1: Quantity 2 sets, fixed on the welding clamp. Each sensor has a measurement range of no less than 200 mm in the X, Y, and Z coordinate axes, and a single-axis measurement accuracy better than 0.5 mm.

[0072] Industrial PC 9: 1 unit, serving as the core computing unit. Specific configuration: Intel Core i7-118G7 processor (3.00GHz); 16GB RAM (two 8GB modules in dual-channel configuration); 512GB SSD for system and data storage; dedicated graphics card (NVIDIA GeForce GT730, 4GB VRAM); Windows 10 Professional operating system.

[0073] Touchscreen Display 7: Quantity 1 unit, screen size 17 inches or larger, supporting multi-touch operation.

[0074] Visual computing software: One set of Chenbei Vision vision software, responsible for the acquisition, processing and feature coordinate calculation of laser images.

[0075] System Startup and Connection: After the equipment is powered on, the industrial PC 9 automatically starts the human-machine interface software and the Chenbei Vision vision software. The operator must confirm that the power indicator light on the power distribution cabinet 2 on the welding clamp is green and that the industrial PC 9 is connected to the sensor unit via WLAN. After the system completes its self-test, the operator can select the working mode using the knob to begin operation.

[0076] In summary, this invention achieves high-precision weld point positioning through an innovative "horizontal intersection method" image algorithm. Combined with an intelligent three-level state judgment and decision-making process, a flexible human-machine collaboration mechanism, multi-mode operation support, and highly integrated hardware and software equipment, it constitutes a precise, efficient, reliable, and easy-to-operate and maintain gantry spot welding laser measurement and adaptive correction method and equipment, effectively improving the automation level, welding quality, and production efficiency of gantry spot welding.

[0077] Obviously, the embodiments described above are merely some embodiments of the present invention, not all embodiments. The accompanying drawings show preferred embodiments of the present invention, but do not limit the patent scope of the present invention. The present invention can be implemented in many different forms; rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments, or make equivalent substitutions for some of the technical features. Any equivalent structures made using the content of this specification and drawings, directly or indirectly applied to other related technical fields, are similarly within the patent protection scope of this invention.

Claims

1. A laser measurement and adaptive correction method for gantry spot welding, characterized in that, Includes the following steps: S1. Move the welding clamp to the target welding point position; S2. Trigger laser measurement to obtain the actual three-dimensional coordinates of the weld point; S3. Read the preset standard coordinates from the recipe; S4. Compare the actual three-dimensional coordinates with the preset standard coordinates, and calculate the deviation values ​​ΔX, ΔY, and ΔZ in the X, Y, and Z coordinate axes. S5. Compare the deviation values ​​of each coordinate axis direction with the preset allowable deviation threshold and the out-of-tolerance alarm threshold respectively to generate a three-level state judgment result. The three-level state includes normal state, state requiring adjustment and abnormal state. S6. If the judgment result is an abnormal state, then proceed to the human-machine collaborative abnormal handling process. S7. If the judgment result is a normal state or a state that needs adjustment, then a correction command is generated based on the deviation value to drive the welding gun to perform position compensation. S8. After the position compensation is completed, the retest process is triggered. Steps S2 to S5 are repeated, and the welding operation is decided based on the retest results, or the human-machine collaborative abnormal handling process is entered.

2. The gantry spot welding laser measurement and adaptive correction method according to claim 1, characterized in that, The laser measurement in step S2 uses a laser image algorithm, and the specific rules of the laser image algorithm are as follows: S21, Image Acquisition: The welding area is scanned by a laser tracking sensor (1) to acquire a two-dimensional laser image of the welding part; S22. Determine the starting point: Select a processing area in the laser two-dimensional image and identify the highest gray level or height point in the area as the starting point; S23. Obtain the intersection points: Draw two horizontal lines of different heights downwards along the vertical direction from the starting point, and obtain two intersection points between the two horizontal lines and the image outline; S24. Fitting the characteristic line: Using the principle of point-to-point straight line, fit the characteristic line of the board through these two intersection points; S25. Calculate feature points: Calculate the intersection points of the feature line and the horizontal line passing through the starting point to obtain the feature points; S26. Coordinate transformation: Convert the image coordinates of the feature points into actual three-dimensional coordinates, which are used as the actual positions of the solder joints.

3. The gantry spot welding laser measurement and adaptive correction method according to claim 1, characterized in that, The specific rules for the three-level state judgment in step S5 are as follows: S51. When the deviation values ​​of all coordinate axis directions are less than or equal to the allowable deviation threshold, it is judged as a normal state. S52. When the deviation value in any coordinate axis direction is greater than the allowable deviation threshold but less than or equal to the over-tolerance alarm threshold, it is determined to be in an adjustment state; when the deviation value in any coordinate axis direction is greater than the over-tolerance alarm threshold, it is determined to be in an abnormal state.

4. The gantry spot welding laser measurement and adaptive correction method according to claim 1, characterized in that, Step S8 describes determining whether to perform the welding operation or enter the human-machine collaborative anomaly handling process based on the retest results. The specific rules of the human-machine collaborative anomaly handling process are as follows: S61. When the retest result indicates a state requiring adjustment or an abnormal state, the equipment will pause and trigger the corresponding alarm indication. S62. In response to the operator's action selection, execute any of the following branches: The system receives the desired correction value input by the operator on the user correction interface, drives the welding gun to perform secondary position compensation, and then executes the retest process again. In response to the operator's mandatory confirmation command, the welding operation is performed directly without subsequent compensation.

5. The gantry spot welding laser measurement and adaptive correction method according to claim 1, characterized in that, The gantry spot welding laser measurement and adaptive correction method supports multiple working modes, including: Automatic online mode: In this mode, the equipment automatically executes a closed-loop control process of measurement, retesting, and automatic correction; when the retest result is normal, the system automatically confirms the welding; when the retest result is in an adjustment state or an abnormal state, manual intervention is required. Automatic offline mode: In this mode, the device automatically performs measurement and retest functions, but does not drive the welding gun to perform automatic deviation correction; Manual mode: In this mode, the device only responds to manual commands to perform measurements and display results; all actions require manual confirmation.

6. The gantry spot welding laser measurement and adaptive correction method according to claim 1, characterized in that, The gantry spot welding laser measurement and adaptive correction method also includes a recipe management mechanism: multiple sets of welding recipes are pre-stored, each recipe being associated with at least one program number and weld point number, and containing corresponding standard coordinates, allowable deviation thresholds, out-of-tolerance alarm thresholds, and weld point compensation values; the recipes are divided into model recipes and welded plate beam model recipes; wherein, model recipes are used to set allowable deviation thresholds and weld point compensation values, and welded plate beam model recipes are used to set standard coordinates and whether each coordinate axis is corrected; the model recipes and welded plate beam model recipes are automatically called by the process in automatic mode, and can be freely modified by the operator in manual mode; the specific parameter values ​​of the recipes can be modified in all modes, and the modification must follow the process of "start modification, input value, save and take effect".

7. The gantry spot welding laser measurement and adaptive correction method according to claim 1, characterized in that, The gantry spot welding laser measurement and adaptive correction method also includes an optional manual calibration mechanism: when the equipment is working in manual or automatic mode, the operator can manually trigger the calibration process; when performing calibration, the equipment updates the actual coordinates obtained by the current weld point measurement to the standard coordinates of the point, and calculates and stores them as weld point position compensation values; the calibration mechanism is used to compensate for systematic errors generated when measuring non-planar workpieces.

8. The gantry spot welding laser measurement and adaptive correction method according to claim 1, characterized in that, The gantry spot welding laser measurement and adaptive correction method also includes a graded alarm mechanism, with alarm levels including: Level L1 alarm: Automatic mode status is disconnected, automatic mode process is stopped, and immediate action is required, including emergency stop triggering, vision software not started or sensor connection disconnected. Level L2 alarm: Prevents automatic mode from proceeding, including when measurement results exceed the out-of-tolerance alarm threshold; Level L3 alarm: A warning alarm that also prevents the automatic mode process from proceeding until an operator responds, including when the deviation value exceeds the allowable deviation threshold or when the external controller malfunctions.

9. A gantry spot welding laser measurement and adaptive correction device for implementing the gantry spot welding laser measurement and adaptive correction method according to any one of claims 1-8, characterized in that, include: The sensor unit includes two laser tracking sensors (1) fixedly mounted on the welding clamp and a power distribution cabinet (2) for powering the laser tracking sensors (1), which is used to acquire the actual three-dimensional coordinates of the welding point in real time and transmit the measurement data through a wireless local area network (WLAN). The integrated control cabinet, serving as the central control and interaction platform for the equipment, integrates the following on its front panel: The three-color indicator light (3) is used to intuitively indicate the overall working status and alarm level of the equipment; WLAN access device (4) is used to establish a wireless communication link with the sensor unit; The monitoring screen (5) is used for global monitoring of the welding clamp and workpiece status; The physical operation panel (6) is provided with a power knob (61), a mode selection knob (62) for switching between manual and automatic modes, a measurement button (63), a movement button (64), a confirmation welding button (65), a reset button (66) and an emergency stop button (67). The touch display screen (7) is used for core parameter setting, data display and function touch operation; The integrated control cabinet integrates an industrial computer (9), a programmable logic controller (PLC) (10), a network switch (11), and a power supply component. The industrial computer (9) constitutes a control and decision-making unit, runs vision computing software (Chenbei Vision vision software), and is used to receive and process sensor data, and execute coordinate calculation, deviation calculation, three-level state judgment, and control decision logic in the methods described in claims 1-8. The programmable logic controller (PLC) (10) constitutes an execution control unit, which is used to receive decision instructions from the industrial computer (9) and drive the external welding robot and welding machine to perform corresponding movement, correction, and welding actions. The network switch (11) is used to establish a wired data communication network between the components in the control cabinet and to the outside. The power supply component includes an air switch (81), a DC 24V power module (82), a switching power supply (83), and an AC 220V power socket (84).

10. The gantry spot welding laser measurement and adaptive correction device according to claim 9, characterized in that: The laser tracking sensor (1) has a measurement range of not less than 200 mm in each of the X, Y, and Z coordinate axes, and a single-axis measurement accuracy of not less than 0.5 mm. The industrial computer (9) has a built-in processor, memory, independent graphics card and solid-state drive; The data acquisition and processing cycle of the visual computing software meets the following requirement: the time for a single loop from data acquisition to the completion of deviation value calculation is no more than 5 milliseconds; The touch screen (7) runs human-computer interaction software, and the human-computer interaction interface presented includes at least: The main interface dynamically displays the program number, weld point number, operation mode, detection position, measured values ​​of each coordinate axis, standard value, deviation value, and three-level status judgment results. It also provides virtual buttons for measurement and re-measurement, as well as a welding confirmation mode switching function. The calibration interface provides a manual calibration function, which is used to update the standard coordinates and generate solder joint position compensation values ​​after confirming the solder joint position. The recipe management interface is used to store, retrieve, and edit welding recipes that include standard coordinates, allowable deviation thresholds, out-of-tolerance alarm thresholds, and weld point compensation values. It supports the classification management of model recipes and welded plate beam model recipes. The user correction interface provides an interactive function to input the desired correction value and trigger secondary position compensation when the retest result is abnormal. The data recording interface is used to query historical measurement and retest data, and supports filtering by time and recording measurement values, deviation values ​​and weld point information for each coordinate axis. An interactive information interface is used to monitor the real-time communication status between various components within the system; The alarm log interface is used to centrally display and trace alarm information at all levels that occur in the system.

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