A method and device for measuring the resistance of a resistance spot welding electrode body and a storage medium

Abstract

This invention relates to a method, apparatus, and storage medium for measuring the resistance of a resistance spot welding electrode body, belonging to the field of welding technology. This application eliminates contact resistance by setting a first-duration pre-pressure energization, maintaining pressure after power-off, and determining whether the electrode has cooled to room temperature based on electrode displacement signals. Different current pulses are repeatedly applied according to a set second duration, and electrode voltage and welding current data are sampled and recorded in real time. After energization ends, pressure is maintained, and the electrode is determined to have cooled to room temperature based on electrode displacement signals before the next energization. The measured value of the body resistance is calculated using effective voltage and current data points. This application eliminates the influence of irregular protrusions and oil contamination on the electrode cap end face through pre-pressure energization, ensuring the reliability of the measurement results. Determining whether the electrode has cooled to room temperature before energizing based on electrode displacement signals eliminates the influence of temperature on the body resistance measurement, ensuring the accuracy of the measurement results.

Description

Technical Field

[0001] This invention relates to the field of welding technology, and in particular to a method, apparatus and storage medium for measuring the resistance of a resistance spot welding electrode body. Background Technology

[0002] Resistance spot welding is a metallurgical joining process that uses a large current to melt the metal workpiece by heating it with Joule heat. The size of the weld nugget is a key factor determining the weld quality. However, the weld nugget in resistance spot welding is located at the interface of the laminated plates, making it closed and invisible, and impossible to observe directly visually. To monitor weld quality in real time, the growth of the weld nugget can only be indirectly inferred by monitoring sensor signals accompanying the welding process. Dynamic resistance is one of the most widely used sensor signals, consisting of three parts: electrode body resistance, workpiece body resistance, and interface contact resistance. Among these, workpiece body resistance is strongly correlated with weld nugget growth, interface contact resistance is eliminated under the influence of the welding current, and electrode body resistance is not related to weld nugget growth. Therefore, it is necessary to accurately measure the electrode body resistance and subtract it from the dynamic resistance signal to achieve accurate monitoring of the workpiece body resistance.

[0003] Existing methods for measuring electrode resistance generally employ a single-pulse process with no-workpiece welding experiments. This involves directly applying a welding current between the two electrodes while simultaneously measuring the voltage between them, and then using Ohm's law to calculate the resistance value as the electrode resistance measurement. This method has two problems: 1) If the welding current is too small, the contact resistance between the electrodes is not completely eliminated, and the measurement result includes contact resistance interference; 2) If the welding current is too large, the electrodes themselves will experience a significant temperature rise due to Joule heating during the measurement process, thereby increasing the electrode resistivity and leading to an inflated measurement result. Clearly, it is necessary to select an appropriate welding current based on the electrode and interface contact state. However, in mass production lines, the electrode end faces wear down with each welding cycle, causing the contact interface state between the two electrodes to constantly change, making it difficult to achieve high-precision measurement of electrode resistance by setting a uniform welding current. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, or at least partially solve the above-mentioned technical problems, the present invention provides a method, device and storage medium for measuring the resistance of a resistance spot welding electrode body.

[0005] In a first aspect, the present invention provides a method for measuring the resistance of a resistance spot welding electrode body, comprising: connecting upper and lower electrodes together, eliminating interface contact resistance by setting a pre-pressure energization for a first duration, maintaining pressure after power-off, and determining the electrode cooling to room temperature based on the electrode displacement signal;

[0006] Different current pulses of different magnitudes are repeatedly applied according to the set second duration. During each power-on process, the electrode voltage and welding current data are sampled and recorded in real time. After each power-on, the voltage is maintained and the electrode is judged to have cooled to room temperature based on the electrode displacement signal after power-off before the next power-on is performed.

[0007] By using effective voltage and current data points, a statistical method is employed to fit the current-voltage characteristic curve, and the measured value of the body resistance is obtained based on the curve.

[0008] Furthermore, the step of determining that the electrode has cooled to room temperature based on the electrode displacement signal includes: constructing a second mapping table between the electrode cap type and the peak range of electrode displacement and the room temperature electrode displacement threshold; determining the room temperature electrode displacement threshold based on the second mapping table, the electrode cap type, and the peak value of the electrode displacement; if the electrode displacement value is less than the room temperature electrode displacement threshold after power is cut off, it is determined that the electrode has been sufficiently cooled; otherwise, it is considered that the electrode has not been sufficiently cooled.

[0009] Furthermore, determining the effective voltage and current data points includes:

[0010] The contact resistance is eliminated by setting a first-duration pre-voltage energization, and the electrode displacement is measured and the reference electrode displacement characteristic value is recorded during this process.

[0011] Different current pulses of different magnitudes are repeatedly applied according to the set second duration. During each energization process, the electrode voltage, welding current and electrode displacement data are sampled and recorded in real time within the effective time, and the real-time electrode displacement characteristic value is calculated.

[0012] When the real-time electrode displacement characteristic value is lower than the reference electrode displacement characteristic value, the recorded voltage and current data points are valid.

[0013] Furthermore, the electrode displacement characteristic value refers to the weighted sum of the maximum and average values ​​of the electrode displacement during the current pulse conduction phase.

[0014] Furthermore, a first mapping table is constructed to map the electrode cap type and the peak range of electrode displacement to the preset range of holding time. According to the first mapping table, the preset range of holding time is set based on the electrode cap type and the peak range of electrode displacement to set the preset value of holding time. Based on the preset value, the holding time is dynamically determined based on the adjustment value.

[0015] Furthermore, the extra time required for the electrode displacement to drop to the room temperature electrode displacement threshold after exceeding the preset holding time is used as an adjustment value. The preset value and the adjustment value are added together to obtain the holding time after each power-on.

[0016] Furthermore, the effective voltage and current data of the same current pulse during the energizing phase are averaged to obtain the average voltage and average current values ​​of the current pulse. Then, a scatter plot of the current-voltage characteristic is constructed using the average current and average voltage values ​​of different current pulses. The current-voltage characteristic curve is fitted to the scatter plot using a linear regression method, and the derivative is used to obtain the measured value of the body resistance.

[0017] Secondly, the present invention provides a resistance measuring device for a resistance spot welding electrode body based on multi-pulse, for implementing the resistance measuring method for the resistance spot welding electrode body, comprising: an electrode formed by an electrode cap, an upper electrode rod, and a lower electrode rod; the upper electrode rod and the lower electrode rod are respectively connected to the electrode cap;

[0018] A pressurizing mechanism that connects two electrodes and aligns the electrode caps on the upper and lower electrode rods.

[0019] A current sensor is fitted onto the electrode, and a displacement sensor and a voltage sensor for measuring electrode displacement and voltage are respectively installed on the upper electrode rod and the lower electrode rod.

[0020] The pressurization mechanism, current sensor, voltage sensor, and displacement sensor are electrically connected to the controller.

[0021] Preferably, the displacement sensor is a grating ruler displacement sensor or a laser displacement sensor.

[0022] Thirdly, the present invention provides a readable storage medium storing a computer program, which, when executed by a processor, implements the resistance measurement method for the resistance spot welding electrode body.

[0023] The technical solutions provided in the embodiments of the present invention have the following advantages compared with the prior art:

[0024] This invention comprehensively solves the problems of low accuracy and large influence of electrode temperature on electrode body resistance measurement results in resistance spot welding process, as well as the problems of large dynamic resistance signal correction error and uncertain electrode cap replacement criteria caused by this.

[0025] Compared with existing technologies, this invention eliminates the influence of irregular protrusions and oil contamination on the electrode cap end face through pre-pressure energization, ensuring the reliability and consistency of the body resistance measurement results. Simultaneously, before each energization measurement, the electrode temperature is cooled to room temperature based on the dynamic electrode displacement signal, eliminating the influence of temperature on the body resistance measurement. The slope of the volt-ampere characteristic curve is extracted as the body resistance measurement value, ensuring the accuracy of the measurement results. This method is suitable for removing the body resistance from the dynamic resistance signal, enhancing the correlation between the signal and the spot weld quality, and can also be used to guide the timely replacement of electrode caps in welding production. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 A flowchart of a method for measuring the resistance of a resistance spot welding electrode body provided by the present invention;

[0029] Figure 2 Schematic diagrams of various welding caps;

[0030] Figure 3 A mapping table for electrode cap type, electrode cap displacement peak range and preset value range, and room temperature electrode displacement threshold provided by the present invention;

[0031] Figure 4 This is a schematic diagram of the arc-shaped conical top type electrode cap used as an embodiment in this invention;

[0032] Figure 5 This is a schematic diagram of a resistance measuring device for a resistance spot welding electrode body according to an embodiment of the present invention;

[0033] Figure 6 This is a schematic diagram showing the current pulses and corresponding electrode displacements at each stage of resistance measurement of the resistance spot welding electrode body in an embodiment of the present invention.

[0034] Figure 7 This is a table showing the preset and adjustable values ​​of the holding time during the holding and cooling process for measuring the resistance of the resistance spot welding electrode body in this embodiment of the invention.

[0035] Figure 8 This is a schematic diagram showing the current pulses and corresponding resistance changes at each stage of resistance measurement of the resistance spot welding electrode body in an embodiment of the present invention.

[0036] Figure 9 This is a comparison chart of the test results of the current-voltage characteristic curves in the embodiments of the present invention and the current-voltage characteristic curves in the prior art.

[0037] Labels and their meanings in the diagram:

[0038] 1. Electrode cap, 2. Upper electrode rod, 3. Lower electrode rod, 4. Current sensor, 5. Upper electrode intrinsic process signal sensor assembly, 6. Lower electrode intrinsic process signal sensor assembly, 7. Pressurization mechanism. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0041] Example 1

[0042] This invention provides a method for measuring the resistance of a resistance spot weld body based on multi-pulse welding, including:

[0043] Stage 1 Pre-processing. The upper and lower electrodes are joined together. A pre-pressure energizer of a set duration is applied to eliminate contact resistance, and electrode displacement is measured and recorded. After power is cut off, pressure is maintained, and the electrodes are judged to have cooled to room temperature based on the electrode displacement signal. The electrode displacement refers to the change in the relative distance between the two electrodes during resistance spot welding. Stage 1 pre-processing is the stage for eliminating contact resistance at the electrode interface. A set pressure is applied to the two electrodes. After the two electrodes make contact, a current pulse of a set amplitude and duration is applied, while simultaneously measuring electrode displacement data and calculating the reference electrode displacement characteristic value.

[0044] The first energizing duration (phase one) is set to be longer than the second energizing duration (phase two), also known as the second duration. The first energizing current amplitude is set to be greater than the second energizing current amplitude. The electrode displacement characteristic value refers to the maximum electrode displacement S during the current pulse conduction period. max and average value S avg The weighted sum, i.e. S f =αS max +(1-α)S avg The weight α ranges from 0 to 1, and in this embodiment, α = 0.8.

[0045] The step of determining whether the electrode has cooled to room temperature based on the electrode displacement signal includes: constructing a second mapping table between the electrode cap type and the peak range of electrode displacement and the room temperature electrode displacement threshold; determining the room temperature electrode displacement threshold based on the second mapping table, the electrode cap type, and the peak value of the electrode displacement; if the electrode displacement value is less than the room temperature electrode displacement threshold after power is cut off, it is determined that the electrode has been sufficiently cooled; otherwise, it is considered that the electrode has not been sufficiently cooled.

[0046] Phase Two: Electrical Measurement. The electrical measurement refers to applying a current pulse between the upper and lower electrode rods. During the electrical process, voltage and current sensors are used to sample and record electrode voltage, welding current, and electrode displacement data in real time, and to calculate the real-time electrode displacement characteristic value.

[0047] When the real-time electrode displacement characteristic value is lower than the reference electrode displacement characteristic value, the recorded voltage and current data points are valid. Since the energizing duration of Phase 1 (the first duration) is longer than the energizing duration of Phase 2 (the second duration), and the energizing current amplitude of Phase 1 is set to be greater than the energizing current amplitude of Phase 2, the reference electrode displacement characteristic value should be greater than the real-time electrode displacement characteristic value; otherwise, it indicates an anomaly, and the abnormal electrode voltage and welding current data are discarded.

[0048] The electrode current refers to the total current flowing through the electrode, and the electrode voltage refers to the potential difference between the measurement points of the two electrodes.

[0049] During the measurement, the current is applied several times with different magnitudes. After each application, the voltage is maintained and the electrode is cooled to room temperature based on the electrode displacement signal before the next application is performed.

[0050] The pressure holding and cooling function supports execution according to a set time or can be adjusted based on the cooling situation. When executing according to a set time, a preset value for the pressure holding time is set based on the electrode cap type and the peak range of electrode displacement, such as... Figure 3 As shown in the table, the range of preset values ​​is related to the electrode cap type and the peak value of the electrode displacement. Figure 3 Different types of electrode caps, such as Figure 2 As shown, a is an arc-shaped dome electrode cap, b is an arc-shaped conical electrode cap, c is a spherical electrode cap, d is a flat-topped straight electrode cap, e is a flat conical electrode cap, and f is an arc-shaped straight electrode cap. In the specific implementation process, a first mapping table is constructed to map the electrode cap type and the peak electrode displacement range to the preset range of the holding time. According to the first mapping table, the preset range of the holding time is set based on the electrode cap type and the peak electrode displacement range to determine the preset value of the holding time. When making specific adjustments based on the cooling situation, the holding time is dynamically determined based on the adjustment value on top of the preset value. The extra time required for the electrode displacement to drop to the room temperature electrode displacement threshold after exceeding the preset holding time is used as the adjustment value. The preset value and the adjustment value are added together to obtain the holding time after each power-on cycle.

[0051] Phase Three: Data Processing. Using the recorded voltage-current data points, a statistical method is employed to fit the volt-ampere characteristic curve, and the measured value of the body resistance is obtained from the curve. The electrode voltage and welding current data of the same current pulse are averaged to obtain the average voltage and average current values ​​of that current pulse. Then, a volt-ampere characteristic scatter plot is constructed using the average current and average voltage values ​​of different current pulses. A linear regression method is used to fit the volt-ampere characteristic curve to the characteristic scatter plot, and the derivative is used to obtain the measured value of the body resistance. The body resistance determination refers to using a statistical method to fit the volt-ampere characteristic curve and obtaining the measured value of the body resistance from the curve. Since the influence of temperature on resistance is eliminated, the volt-ampere characteristic curve obtained by this invention is a straight line passing through the origin, and the slope of the straight line represents the measured value of the body resistance.

[0052] Example 2

[0053] like Figure 5 As shown, this embodiment relates to a resistance measurement device for a resistance spot welder body based on multi-pulse, including: an electrode formed by an electrode cap 1, an upper electrode rod 2, and a lower electrode rod 3; the upper electrode rod 2 and the lower electrode rod 3 are respectively connected to the electrode cap 1;

[0054] A pressurizing mechanism 7 connects two electrodes and aligns the electrode caps 1 on the upper electrode rod 2 and the lower electrode rod 3.

[0055] A current sensor 4 is fitted onto the electrode. A displacement sensor and a voltage sensor for measuring electrode displacement and voltage are respectively installed on the upper electrode rod 2 and the lower electrode rod 3. The displacement sensor is a grating ruler displacement sensor or a laser displacement sensor.

[0056] The pressurization mechanism 7, current sensor 4, voltage sensor and displacement sensor are electrically connected to the controller.

[0057] In one embodiment, a current sensor 4, which is a Rogowski coil current sensor, is sleeved on the lower electrode rod 3. An upper electrode intrinsic process signal sensor assembly 5 and a lower electrode intrinsic process signal sensor assembly 6 are respectively installed on the upper electrode rod 2 and the lower electrode rod 3. The upper electrode intrinsic process signal sensor assembly 5 includes a grating ruler displacement sensor and a voltage sensor; the lower electrode intrinsic process signal sensor assembly 6 includes a laser displacement sensor and a voltage sensor.

[0058] by Figure 4 Taking the arc-shaped conical electrode cap shown as an example, this embodiment implements a multi-pulse resistance spot welding body resistance measurement method. In this embodiment, the radius of curvature R of the electrode cap end face... t The electrode cap end face diameter is 50mm. tThe diameter is 5mm, the top cone angle θ is 75°, and the bottom diameter D of the electrode cap is 16mm.

[0059] Before measurement, the electrodes are closed relative to each other and a certain pressure is applied. Throughout the measurement process, the pressure between the upper and lower electrode rods is maintained. In this embodiment, the electrode pressure is maintained at 2.6 kN.

[0060] like Figure 6 As shown, the entire process consists of two stages:

[0061] Phase 1 Pre-treatment. A pre-current I1 is applied to eliminate unevenness and oil contamination on the end face of electrode cap 1, with a duration of T1. Then, a cooling period of T3 begins, during which the current is stopped, and the electrode is judged to have cooled to room temperature based on the dynamic electrode displacement signal. In this embodiment, I1 in Phase 1 is set to 4kA, and the duration T1 is 80ms.

[0062] Phase Two: Energization Measurement. The energization measurement phase refers to the stage where different magnitudes of current are conducted at regular intervals, and current-voltage data is sampled and recorded in real time. Figure 6 In the example shown, the current magnitude is I2 to I6, the energizing time is uniformly T2, and the sampling frequency is f1. The next measurement is performed after the electrode cools to room temperature based on the dynamic electrode displacement signal, with an interval of T4 to T7. In this embodiment, the pulse currents I2 to I6 in stage two are 2kA, 3kA, 4kA, 5kA, and 6kA, respectively, the energizing time T2 is 20ms, and the sampling frequency f1 = 500Hz during the energizing measurement.

[0063] Figure 6 The dynamic electrode displacement signals for stages one and two are also provided. These dynamic electrode displacement signals correspond to each stage of the measurement process, and the room temperature electrode displacement thresholds S3 to S7 for each stage are marked with dotted lines. The electrode displacement after electrode closure and pressure application is set as zero. As the electrode temperature decreases during the pressure holding stage, the electrode displacement value decreases accordingly. The observation frequency is set to f2. The extra time required for the electrode displacement to decrease to the room temperature electrode displacement threshold after exceeding the preset pressure holding time is used as the adjustment value to obtain the pressure holding stage time after each power-on, i.e., T3 to T7. The preset values, adjustment values, and room temperature electrode displacement thresholds for each stage are as follows: Figure 7 As shown in the table, the observation frequency f2 = 100 Hz.

[0064] like Figure 8As shown, in this embodiment, the electrode contact resistance is essentially eliminated during the pretreatment stage, and the electrodes remain closed during the measurement stage, thus eliminating the influence of contact resistance. The dashed line represents the change in body resistance during the pressure holding and cooling stage. Before each measurement, the body resistance returns to room temperature, and during the power-on measurement process, the body resistance increases only within a limited range, effectively eliminating the influence of temperature on the body resistance measurement.

[0065] like Figure 9 As shown in the left figure, this embodiment averages the voltage data from five current measurements based on the sampled voltage-current data, obtaining five voltage-current data points. The volt-ampere characteristic curve is then fitted using the least squares method. Since the influence of temperature on resistance is eliminated, the volt-ampere characteristic curve obtained by this invention is a straight line passing through the origin, and the slope of the line represents the measured value of the bulk resistance. The final fitted volt-ampere characteristic curve equation is U = 105.3I, and the measured value of the bulk resistance is 105.3 μΩ. Traditional bulk resistance measurement methods cannot eliminate the influence of temperature on resistance, and the resulting volt-ampere characteristic curve is shown in the diagram below. Figure 9 The figure on the right shows a curve with a gradually increasing slope, which causes the measured resistance value of the body to gradually increase and the measurement error to increase accordingly.

[0066] Compared with existing technologies, this invention eliminates the influence of irregular protrusions and oil contamination on the electrode cap end face through pre-pressure energization, ensuring the reliability and consistency of the body resistance measurement results. Simultaneously, before each energized measurement, the time required for the electrode temperature to cool to room temperature is determined based on the dynamic electrode displacement signal, eliminating the influence of temperature on the body resistance measurement. Figure 9 As shown, compared to traditional measurement methods, the current-voltage characteristic curve obtained by the multi-pulse-based body resistance measurement method is a straight line with a constant slope. Extracting the slope of the current-voltage characteristic curve as the measured body resistance value ensures the accuracy of the measurement results. This method is suitable for eliminating the electrode body resistance from dynamic resistance signals, thereby achieving precise monitoring of the workpiece's body resistance.

[0067] Example 3

[0068] The present invention provides a readable storage medium storing a computer program, which, when executed by a processor, implements the resistance measurement method for the resistance spot welding electrode body.

[0069] In the embodiments provided by this invention, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the circuit description and division are only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling shown or discussed may be indirect coupling through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0070] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for measuring the resistance of a resistance spot welding electrode body, characterized in that, include: Connect the upper and lower electrodes, eliminate the interface contact resistance by setting a first time of pre-pressure energization, maintain the pressure after power is cut off, and determine the electrode cooling to room temperature based on the electrode displacement signal. Different current pulses of different magnitudes are repeatedly applied according to the set second duration. During each power-on process, the electrode voltage and welding current data are sampled and recorded in real time. After each power-on, the voltage is maintained and the electrode is judged to have cooled to room temperature based on the electrode displacement signal after power-off before the next power-on is performed. By using effective voltage and current data points, a statistical method is employed to fit the volt-ampere characteristic curve, and the measured value of the body resistance is obtained from the curve. The determination of effective voltage and current data points includes: eliminating contact resistance by pre-voltage energizing for a set first duration and measuring electrode displacement data during this process, recording a reference electrode displacement characteristic value, where the electrode displacement characteristic value is the weighted sum of the maximum and average electrode displacement values ​​during the current pulse conduction phase; repeatedly applying current pulses of different magnitudes for a set second duration, and sampling and recording electrode voltage, welding current, and electrode displacement data in real time during each energizing process, and calculating the real-time electrode displacement characteristic value; when the real-time electrode displacement characteristic value is lower than the reference electrode displacement characteristic value, the recorded voltage and current data points are considered valid.

2. The method for measuring the resistance of a resistance spot welding electrode body according to claim 1, characterized in that, The step of determining whether the electrode has cooled to room temperature based on the electrode displacement signal includes: constructing a second mapping table between the electrode cap type and the peak range of the electrode displacement and the room temperature electrode displacement threshold; determining the room temperature electrode displacement threshold based on the second mapping table, the electrode cap type, and the peak value of the electrode displacement; if the electrode displacement value is less than the room temperature electrode displacement threshold after power is cut off, it is determined that the electrode has been sufficiently cooled; otherwise, it is considered that the electrode has not been sufficiently cooled.

3. The method for measuring the resistance of a resistance spot welding electrode body according to claim 1, characterized in that, The electrode displacement characteristic value is the weighted sum of the maximum and average values ​​of the electrode displacement during the current pulse conduction phase.

4. The method for measuring the resistance of a resistance spot welding electrode body according to claim 1, characterized in that, A first mapping table is constructed to establish the mapping relationship between electrode cap type and peak electrode displacement range and preset value range of holding time. The preset value range of holding time is set according to the electrode cap type and peak electrode displacement range of the electrode in accordance with the first mapping table to set the preset value of holding time.

5. The method for measuring the resistance of a resistance spot welding electrode body according to claim 4, characterized in that, The adjustment value is dynamically set based on the preset value to determine the holding time of each stage. The additional holding time used when the electrode displacement drops to the room temperature electrode displacement threshold after exceeding the preset holding time is used as the adjustment value. The preset value and the adjustment value are added together to obtain the holding time after each current pulse is applied.

6. The method for measuring the resistance of a resistance spot welding electrode body according to claim 1, characterized in that, The effective voltage and current data of the same current pulse during the energizing phase are averaged to obtain the average voltage and average current values ​​of the current pulse. Then, a scatter plot of the current-voltage characteristic is constructed using the average current and average voltage values ​​of different current pulses. The current-voltage characteristic curve is fitted to the scatter plot using a linear regression method, and the derivative is used to obtain the measured value of the body resistance.

7. A multi-pulse-based resistance spot welding electrode body resistance measuring device, characterized in that, include: An electrode is formed by an electrode cap (1), an upper electrode rod (2), and a lower electrode rod (3); the upper electrode rod (2) and the lower electrode rod (3) are respectively connected to the electrode cap (1); A pressurizing mechanism (7) connects two electrodes and aligns the electrode caps (1) on the upper electrode rod (2) and the lower electrode rod (3); A current sensor (4) is fitted onto the electrode, and a displacement sensor and a voltage sensor for measuring electrode displacement and voltage are respectively installed on the upper electrode rod (2) and the lower electrode rod (3); The pressurizing mechanism (7), current sensor (4), voltage sensor, and displacement sensor are electrically connected to the controller to implement the resistance measurement method for the body of the resistance spot welding electrode as described in any one of claims 1-6.

8. The resistance measuring device for resistance spot welding electrode body based on multi-pulse as described in claim 7, characterized in that, The displacement sensor is either a grating ruler displacement sensor or a laser displacement sensor.

9. A readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the resistance measurement method for the body of the resistance spot welding electrode as described in any one of claims 1-6.

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