Multi-sensing measurement method and system for displacement signals of micro-resistance spot welding large cantilever electrode

Abstract

The invention provides a multi-sensing measurement method and system for displacement signals of a micro-resistance spot welding large cantilever electrode, and the method comprises the steps: S1, collecting sensor data in an air compression process, and calibrating the rigidity of an electrode pressurization mechanism; s2, sample welding is conducted, and dynamic signals in the welding process are collected; s3, according to the rigidity of the electrode pressurization mechanism, the pressure signal, the displacement signal and the acceleration signal are coupled to obtain a far-end displacement signal and a near-end vibration signal; and S4, performing vibration filtering on the far-end displacement signal by using the near-end vibration signal to obtain a smooth electrode displacement signal, and completing the measurement process. According to the method, the problem of sensor installation interference occurring when electrode displacement signals are measured in a near-end welding area is solved, the micro spot welding process can be monitored on line under the condition that the welding process is not interfered, the problem of signal jitter caused by insufficient rigidity of a large cantilever electrode pressurization mechanism is solved, and the precision of far-end displacement signal measurement is improved.

Description

Technical Field

[0001] The invention relates to the field of micro resistance spot welding, and in particular to a multi-sensor measurement method and system for a micro resistance spot welding large cantilever electrode displacement signal. Background Art

[0002] Micro-resistance spot welding technology is widely used in the manufacturing process of battery packaging, medical equipment, electronic devices, etc. With the development of intelligent technology, the requirements for the quality of micro-resistance spot welding are constantly increasing. Micro-resistance spot welding workpieces are thin and small in size, and there has always been a lack of reliable quality online detection methods.

[0003] When manually inspecting the quality of welds, fatigue is easily generated due to continuous work, and it is easy to cause missed inspections. In order to replace manual inspection, in the field of traditional resistance spot welding, welding process sensor signals are widely used for online inspection of weld quality, among which the electrode displacement signal has a strong correlation with the quality of welds, and therefore has received widespread attention. However, in the field of micro-resistance spot welding, due to the reduction in workpiece size, the amplitude of the electrode displacement signal drops to about 10% of that of traditional spot welding, making the signal more susceptible to noise caused by mechanism vibration. In addition, in order to increase the operating space, large cantilever structures are often used in production sites, which will produce a larger mechanism vibration amplitude, further increasing the difficulty of measuring electrode displacement signals. Measuring displacement signals at the proximal end of the electrode can ensure measurement accuracy, but it will produce mechanism interference and high measurement costs, which seriously affects the welding production process; while the traditional remote measurement method of electrode displacement signals does not consider vibration filtering, which will lead to large measurement errors when applied in the field of micro-resistance spot welding, limiting the research and application of quality online detection in the field of micro-resistance spot welding. Summary of the invention

[0004] In view of the defects in the prior art, the object of the present invention is to provide a multi-sensor measurement method and system for displacement signals of large cantilever electrodes in micro-resistance spot welding.

[0005] A multi-sensor measurement method for a micro-resistance spot welding large cantilever electrode displacement signal provided by the present invention comprises:

[0006] Step S1: collecting sensor data during the air compression process and calibrating the stiffness of the electrode pressurizing mechanism;

[0007] Step S2: Perform sample welding and collect dynamic signals of the welding process;

[0008] The dynamic signal includes an acceleration signal, a pressure signal and a displacement signal;

[0009] Step S3: according to the stiffness of the electrode pressurizing mechanism, the acceleration signal, the pressure signal and the displacement signal are coupled to obtain a far-end displacement signal and a near-end vibration signal;

[0010] Step S4: Use the proximal vibration signal to perform vibration filtering on the distal displacement signal to obtain a filtered electrode displacement signal, thereby completing the measurement process.

[0011] Preferably, the sensor includes part or all of an upper electrode acceleration sensor, an upper electrode pressure sensor, an upper electrode displacement sensor, a lower electrode acceleration sensor, a lower electrode pressure sensor, and a lower electrode displacement sensor; the step S1 includes setting multiple electrode pressures for air compression, collecting and recording acceleration signals and pressure signals during the air compression process, and measuring the displacement of the electrode end; calibrating the stiffness of the electrode pressurizing mechanism according to the following formula:

[0012] v i (t) = ∫a i (t)dt;

[0013] F i (t) = k·S i (t)+ξ·v i (t)+m·a i (t)

[0014] Among them, F i (t) and a i (t) are the pressure signal and acceleration signal of the air compression stage under different set pressures; S i (t) is the measured electrode end displacement signal in the air compression stage under different set pressures; v i (t) is the velocity signal at the electrode end, obtained by integrating the acceleration signal; i = 1, 2, 3, ..., n, representing the air pressure stage under different gear electrode pressures; k, ξ and m are the stiffness coefficients of the electrode pressurizing mechanism to be calibrated;

[0015] Preferably, step S3 comprises:

[0016] The far-end displacement signal S is calculated according to the following formula r :

[0017] S r =f1(F,S,a)

[0018] Wherein, F is the pressure signal collected by the pressure sensor, S is the displacement signal collected by the displacement sensor, a is the acceleration signal collected by the acceleration sensor, and f1 is the remote displacement signal operation and processing process. The pressure signal, displacement signal and acceleration signal are coupled through the remote displacement signal operation and processing process f1(·) to obtain the remote displacement signal S r ;

[0019] The near-end vibration signal S is calculated according to the following formula v :

[0020] S v=f2(a)

[0021] Among them, f2 is the near-end vibration signal calculation and processing process, and the acceleration signal is processed through the near-end vibration signal calculation and processing process f2(·) to obtain the near-end vibration signal S v .

[0022] Preferably, step S4 includes removing the influence of the proximal vibration signal from the distal displacement signal, using the processed signal as the filtered electrode displacement signal, and:

[0023] S e =f3(S r ,S v );

[0024] Among them, S e represents the electrode displacement signal after filtering, f3 is the vibration filtering operation processing process, and the far-end displacement signal and the near-end vibration signal are processed by the vibration filtering operation processing process f3(·) to obtain the electrode displacement signal S e .

[0025] When different sensors are used for calculation, the forms of the calculation processes f1, f2 and f3 change.

[0026] A multi-sensor measurement system for displacement signals of a large cantilever electrode in micro-resistance spot welding provided by the present invention includes but is not limited to part or all of the following modules:

[0027] Upper electrode, lower electrode, upper electrode cantilever, lower electrode cantilever, upper electrode acceleration sensor, upper electrode pressure sensor, upper electrode displacement sensor, lower electrode acceleration sensor, lower electrode pressure sensor, lower electrode displacement sensor, rack, dynamic signal acquisition module, calculation and analysis module.

[0028] The upper electrode acceleration sensor is mounted on the upper electrode cantilever and is used to collect the acceleration signal of the upper electrode;

[0029] The upper electrode pressure sensor is mounted on the upper electrode cantilever and is used to obtain the pressure signal of the upper electrode;

[0030] The upper electrode displacement sensor is installed on the frame and is used to collect the displacement signal of the upper electrode;

[0031] The lower electrode acceleration sensor is mounted on the lower electrode cantilever and is used to collect the acceleration signal of the lower electrode;

[0032] The lower electrode pressure sensor is installed on the lower electrode cantilever and is used to obtain the pressure signal of the lower electrode;

[0033] The lower electrode displacement sensor is installed on the frame and is used to collect the displacement signal of the lower electrode;

[0034] Each sensor completes signal acquisition based on the dynamic signal acquisition module and sends the data to the calculation and analysis module;

[0035] The calculation and analysis module receives and processes signal data and outputs calculation results.

[0036] When the multi-sensor measurement system includes different modules, the forms of the operation processing processes f1, f2, and f3 also change accordingly. The specific forms will be described in the embodiments, and each form is within the protection scope of the present invention.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1. The present invention utilizes multiple sensors to synchronously collect the welding dynamic signals at the proximal and distal ends of the welding area, obtains a smooth electrode displacement signal, avoids the sensor installation interference problem that may occur when measuring the electrode displacement signal in the proximal welding area, and can monitor the micro spot welding process online without interfering with the welding process.

[0039] 2. The present invention eliminates the problem of displacement signal jitter caused by insufficient stiffness of the large cantilever electrode pressurizing mechanism, and improves the accuracy of remote measurement of displacement signals; compared with the traditional measurement method that does not consider vibration filtering, the jitter degree of the displacement signal obtained by this method is reduced by nearly 87%, which is extremely close to the high-precision measured displacement signal obtained by high-speed photography, providing technical support for subsequent online monitoring of micro-resistance spot welding.

[0040] Other beneficial effects of the present invention will be explained in the specific implementation manner through the introduction of specific technical features and technical solutions. Through the introduction of these technical features and technical solutions, those skilled in the art should be able to understand the beneficial technical effects brought about by the technical features and technical solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0042] Figure 1 The figure is a flow chart of the method of the present invention.

[0043] Figure 2 It is a schematic diagram of the method of the present invention.

[0044] Figure 3 It is a system schematic diagram of the present invention.

[0045] Figure 4 It is an implementation effect diagram of the present invention.

[0046] Reference numerals

[0047] Upper electrode 1 Lower electrode Acceleration sensor 8

[0048] Lower electrode 2 Lower electrode pressure sensor 9

[0049] Upper electrode cantilever 3 Lower electrode displacement sensor 10

[0050] Lower electrode cantilever 4 frame 11

[0051] Upper electrode acceleration sensor 5 Dynamic signal acquisition module 12

[0052] Upper electrode pressure sensor 6 Calculation and analysis module 13

[0053] Upper electrode displacement sensor 7 DETAILED DESCRIPTION

[0054] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0055] Example 1

[0056] Reference Figure 1 and Figure 2 As shown, this embodiment provides a multi-sensor measurement method and system for the displacement signal of a large cantilever electrode in micro-resistance spot welding. Figure 3 As shown, in this embodiment, the system consists of an upper electrode 1, a lower electrode 2, an upper electrode cantilever 3, a lower electrode cantilever 4, an upper electrode displacement sensor 7, a lower electrode acceleration sensor 8, a lower electrode pressure sensor 9, a frame 11, a dynamic signal acquisition module 12 and a calculation and analysis module 13.

[0057] The upper electrode displacement sensor 7 is installed on the frame 11 to collect the displacement signal of the upper electrode 1; the lower electrode acceleration sensor 8 is installed on the lower electrode cantilever 4 to collect the acceleration signal of the lower electrode 2; the lower electrode pressure sensor 9 is installed on the lower electrode cantilever 4 to obtain the pressure signal of the lower electrode 2.

[0058] Each sensor completes signal acquisition based on the dynamic signal acquisition module 12, and summarizes and sends the data to the calculation and analysis module 13; the calculation and analysis module 13 receives and processes the signal data and outputs the calculation results.

[0059] The computing and analyzing module 13 includes a microprocessor, an industrial computer, a PLC, a monitoring instrument, a welding controller, a desktop computer, a laptop computer, a server or a workstation.

[0060] Use the system to do the following:

[0061] Step 1: Collect air compression and sensor data:

[0062] Set different pressures for air compression. Air compression means controlling the upper and lower electrodes to close for a period of time and maintaining a certain electrode pressure, during which no welding current is passed; collect and record the data of the lower electrode acceleration sensor 8 and the lower electrode pressure sensor 9 during the air compression process; the sensor data refers to the output voltage value, which needs to be converted into actual pressure and acceleration according to the sensitivity of the sensor. At the same time, an external sensor is used to measure the displacement of the electrode end.

[0063] Step 2: Calibrate the stiffness of the electrode pressurizing mechanism:

[0064] In the air pressure stage, three different electrode pressures are set, and the electrode proximal acceleration signal a under different set pressures is obtained through the lower electrode acceleration sensor 8. i (t), the electrode pressure signal F under different set pressures is obtained by the lower electrode pressure sensor 9 i (t), and an external sensor is used to measure the electrode proximal displacement signal S under different set pressures i (t), where i = 1, 2, 3.

[0065] Then the signal average value is obtained by the following formula, where v i (t) is the velocity signal near the electrode, F i avg , Represents the average value of pressure, displacement, velocity and acceleration signals, and T is the acquisition time of the air compression stage signal.

[0066] v i (t) = ∫a i (t)dt;

[0067]

[0068] Finally, the stiffness of the electrode pressurizing mechanism is obtained by the following calibration formula, where |·| represents the determinant operation, and k, ξ and m are the stiffness coefficients of the electrode pressurizing mechanism to be calibrated.

[0069]

[0070] Step 3: Sample welding and dynamic signal acquisition:

[0071] The sample is welded and the dynamic signals of the welding process are collected at the same time; the dynamic signals include: the displacement signal S of the root of the upper electrode cantilever collected by the upper electrode displacement sensor 7 m , the acceleration signal a of the lower electrode cantilever end collected by the lower electrode acceleration sensor 8m And the pressure signal F collected by the lower electrode pressure sensor 9. In this embodiment, Figure 2 F, S, a correspond to the pressure signal F, displacement signal S respectively m and acceleration signal a m .

[0072] Step 4: Dynamic signal processing to obtain the far-end displacement signal and the near-end vibration signal:

[0073] The far-end displacement signal refers to the displacement signal far away from the welding area; the pressure signal, displacement signal and acceleration signal are coupled through the far-end displacement signal operation process f1(·) to obtain the far-end displacement signal S r ; The calculation formula of the far-end displacement signal operation processing process f1(·) in this embodiment is:

[0074] v m =∫a m dt;

[0075]

[0076] Among them, v m is the velocity signal at the end of the lower electrode cantilever, S m is the displacement signal, F is the pressure signal, k, ξ and m are the stiffness of the electrode pressing mechanism.

[0077] The near-end vibration signal refers to the vibration signal close to the welding area. The acceleration signal is processed through the near-end vibration signal operation process f2(·) to obtain the near-end vibration signal S v ; The calculation formula of the near-end vibration signal operation processing process f2(·) in this embodiment is:

[0078] S v =∫∫a m dt

[0079] where a m is the acceleration signal.

[0080] Step 5: Vibration filtering to obtain electrode displacement signal:

[0081] The far-end displacement signal S r and the near-end vibration signal S v The electrode displacement signal S is obtained through the vibration filtering operation process f3(·) e , the influence of the near-end vibration signal is deducted from the far-end displacement signal to obtain a smooth displacement signal without jitter, thereby realizing the far-end high-precision measurement of the displacement signal of the micro-cantilever micro-electrode of the micro-resistance spot welding. The calculation formula of the vibration filtering operation processing process f3(·) in this embodiment is:

[0082] S e =Sr -S v ;

[0083] The implementation effects of the present invention are as follows Figure 4 As shown, the multi-sensor high-precision measurement method and system proposed in the present invention can effectively eliminate the electrode displacement signal jitter problem caused by insufficient stiffness of the large cantilever mechanism of micro-resistance spot welding. Compared with the traditional method, the maximum jitter amplitude of the displacement signal is reduced from the original 6.1μm to 0.8μm, which is reduced by nearly 87%; the electrode displacement signal obtained by the method and system proposed in the present invention is very close to the high-precision electrode displacement signal obtained by high-speed photography, and the maximum error is less than 0.5μm, which significantly improves the measurement accuracy of the electrode displacement signal of micro-resistance spot welding.

[0084] The present invention utilizes the sensing measurement results of the air compression stage to calibrate the stiffness of the electrode pressurizing mechanism, then performs sample welding and collects dynamic signals during the welding process, processes the dynamic signals to obtain a far-end displacement signal and a near-end vibration signal, performs vibration filtering on the far-end displacement signal according to the near-end vibration signal, and obtains a smooth and jitter-free electrode displacement signal, thereby realizing far-end high-precision measurement of the large cantilever tiny electrode displacement signal of micro-resistance spot welding, and can monitor the micro-spot welding process online without interfering with the welding process.

[0085] Example 2

[0086] Reference Figure 1 and Figure 2 As shown, this embodiment provides a multi-sensor measurement method and system for the displacement signal of a large cantilever electrode in micro-resistance spot welding. Figure 3 As shown, in this embodiment, the system consists of an upper electrode 1, a lower electrode 2, an upper electrode cantilever 3, a lower electrode cantilever 4, an upper electrode acceleration sensor 5, an upper electrode pressure sensor 6, a lower electrode acceleration sensor 8, a frame 11, a dynamic signal acquisition module 12 and a calculation and analysis module 13.

[0087] The upper electrode acceleration sensor 5 is installed on the upper electrode cantilever 3 to collect the acceleration signal of the upper electrode 1; the upper electrode pressure sensor 6 is installed on the upper electrode cantilever 3 to obtain the pressure signal of the upper electrode 1; the lower electrode acceleration sensor 8 is installed on the lower electrode cantilever 4 to collect the acceleration signal of the lower electrode 2.

[0088] Each sensor completes signal acquisition based on the dynamic signal acquisition module 12, and summarizes and sends the data to the calculation and analysis module 13; the calculation and analysis module 13 receives and processes the signal data and outputs the calculation results.

[0089] The computing and analyzing module 13 includes a microprocessor, an industrial computer, a PLC, a monitoring instrument, a welding controller, a desktop computer, a laptop computer, a server or a workstation.

[0090] Use the system to do the following:

[0091] Step 1: Collect air compression and sensor data:

[0092] Set different pressures for air compression. Air compression means controlling the upper and lower electrodes to close for a period of time and maintaining a certain electrode pressure, during which no welding current is passed; collect and record the data of the upper electrode acceleration sensor 5 and the upper electrode pressure sensor 6 during the air compression process; the sensor data refers to the output voltage value, which needs to be converted into actual acceleration and pressure according to the sensitivity of the sensor. At the same time, an external sensor is used to measure the displacement of the electrode end.

[0093] Step 2: Calibrate the stiffness of the electrode pressurizing mechanism:

[0094] In the air compression stage, three different electrode pressures are set, and the electrode proximal acceleration signal a under different set pressures is obtained through the upper electrode acceleration sensor 5. i (t), the electrode pressure signal F under different set pressures is obtained through the upper electrode pressure sensor 6 i (t), and an external sensor is used to measure the electrode proximal displacement signal S under different set pressures i (t), where i = 1, 2, 3.

[0095] Then the signal average value is obtained by the following formula, where v i (t) is the velocity signal at the proximal end of the electrode, F i avg , Represents the average value of pressure, displacement, velocity and acceleration signals, and T is the acquisition time of the air compression stage signal.

[0096] v i (t) = ∫a i (t)dt;

[0097]

[0098] Finally, the stiffness of the electrode pressurizing mechanism is obtained by the following calibration formula, where |·| represents the determinant operation, and k, ξ and m are the stiffness coefficients of the electrode pressurizing mechanism to be calibrated.

[0099]

[0100] Step 3: Sample welding and dynamic signal acquisition:

[0101] The sample is welded and the dynamic signals of the welding process are collected at the same time; the dynamic signals include: the acceleration signal a of the upper electrode cantilever end collected by the upper electrode acceleration sensor 5 m1, the pressure signal F collected by the upper electrode pressure sensor 6 and the acceleration signal a of the lower electrode cantilever end collected by the lower electrode acceleration sensor 8 m2 In this embodiment, Figure 2 F, S, a correspond to the pressure signal F, acceleration signal a m1 and acceleration signal a m2 .

[0102] Step 4: Dynamic signal processing to obtain the far-end displacement signal and the near-end vibration signal:

[0103] The far-end displacement signal refers to the displacement signal far away from the welding area; the pressure signal F is obtained by the far-end displacement signal operation process f1(·) to obtain the far-end displacement signal S r , the calculation formula of the far-end displacement signal operation processing process f1(·) in this embodiment is:

[0104]

[0105] Wherein, k is the stiffness coefficient of the electrode pressing mechanism.

[0106] The near-end vibration signal refers to the vibration signal close to the welding area, and the acceleration signal a m1 and acceleration signal a m2 The near-end vibration signal S is obtained through the near-end vibration signal calculation process f2(·) v ; The calculation formula of the near-end vibration signal operation processing process f2(·) in this embodiment is:

[0107] v m1 =∫a m1 dt;v m2 =∫a m2 dt;

[0108]

[0109] Among them, v m1 is the velocity signal at the end of the upper electrode cantilever, v m2 is the velocity signal at the end of the lower electrode cantilever, k, ξ and m are the stiffness coefficients of the electrode pressing mechanism.

[0110] Step 5: Vibration filtering to obtain electrode displacement signal:

[0111] The far-end displacement signal S r and the near-end vibration signal S v The electrode displacement signal S is obtained through the vibration filtering operation process f3(·) e, the influence of the near-end vibration signal is deducted from the far-end displacement signal to obtain a smooth displacement signal without jitter, thereby realizing the far-end high-precision measurement of the displacement signal of the micro-cantilever micro-electrode of the micro-resistance spot welding. The calculation formula of the vibration filtering operation processing process f3(·) in this embodiment is:

[0112] S e =S r -S v ;

[0113] Example 3

[0114] Reference Figure 1 and Figure 2 As shown, this embodiment provides a multi-sensor measurement method and system for the displacement signal of a large cantilever electrode in micro-resistance spot welding. Figure 3 As shown, in this embodiment, the system consists of an upper electrode 1, a lower electrode 2, an upper electrode cantilever 3, a lower electrode cantilever 4, an upper electrode acceleration sensor 5, an upper electrode displacement sensor 7, a lower electrode acceleration sensor 8, a lower electrode displacement sensor 10, a frame 11, a dynamic signal acquisition module 12 and a calculation and analysis module 13.

[0115] The upper electrode acceleration sensor 5 is installed on the upper electrode cantilever 3, and is used to collect the acceleration signal of the upper electrode 1; the upper electrode displacement sensor 7 is installed on the frame 11, and is used to collect the displacement signal of the upper electrode 1; the lower electrode acceleration sensor 8 is installed on the lower electrode cantilever 4, and is used to collect the acceleration signal of the lower electrode 2; the lower electrode displacement sensor 10 is installed on the frame 11, and is used to collect the displacement signal of the lower electrode 2.

[0116] Each sensor completes signal acquisition based on the dynamic signal acquisition module 12, and summarizes and sends the data to the calculation and analysis module 13; the calculation and analysis module 13 receives and processes the signal data and outputs the calculation results.

[0117] The computing and analyzing module 13 includes a microprocessor, an industrial computer, a PLC, a monitoring instrument, a welding controller, a desktop computer, a laptop computer, a server or a workstation.

[0118] Use the system to do the following:

[0119] Step 1: Sample welding and dynamic signal acquisition:

[0120] In this embodiment, the stiffness of the electrode pressing mechanism does not need to be calibrated. First, the sample is welded, and the dynamic signal of the welding process is collected at the same time; the dynamic signal includes: the acceleration signal a of the upper electrode cantilever end collected by the upper electrode acceleration sensor 5 m1 , the displacement signal S of the upper electrode cantilever root collected by the upper electrode displacement sensor 7 m1 , the acceleration signal a of the lower electrode cantilever end collected by the lower electrode acceleration sensor 8m2 and the displacement signal S of the root of the lower electrode cantilever collected by the lower electrode displacement sensor 10 m2 In this embodiment, Figure 2 F, S, a corresponds to the displacement signal S m1 , S m2 And the acceleration signal a m1 、a m2 .

[0121] Step 2: Dynamic signal processing to obtain the far-end displacement signal and the near-end vibration signal:

[0122] The far-end displacement signal refers to the displacement signal far away from the welding area; the displacement signal S m1 , S m2 The far-end displacement signal S is obtained through the far-end displacement signal calculation process f1(·) r , the calculation formula of the far-end displacement signal operation processing process f1(·) in this embodiment is:

[0123] S r =S m1 +S m2

[0124] The near-end vibration signal refers to the vibration signal close to the welding area, and the acceleration signal a m1 、a m2 The near-end vibration signal S is obtained through the near-end vibration signal calculation process f2(·) v ; The calculation formula of the near-end vibration signal operation processing process f2(·) in this embodiment is:

[0125] S v =∫∫a m1 dt+∫∫a m2 dt

[0126] Step 3: Vibration filtering to obtain electrode displacement signal:

[0127] The far-end displacement signal S r and the near-end vibration signal S v The electrode displacement signal S is obtained through the vibration filtering operation process f3(·) e , the influence of the near-end vibration signal is deducted from the far-end displacement signal to obtain a smooth displacement signal without jitter, thereby realizing the far-end high-precision measurement of the displacement signal of the micro-cantilever micro-electrode of the micro-resistance spot welding. The calculation formula of the vibration filtering operation processing process f3(·) in this embodiment is:

[0128] S e =S r -S v ;

[0129] The far-end displacement signal Sr and the near-end vibration signal S v Substituting the above formula, the filtered electrode displacement signal S can be obtained. e , realizing remote high-precision measurement of the displacement signal of the small electrode of the large cantilever of micro-resistance spot welding.

[0130] The present invention utilizes multiple sensors to synchronously collect welding dynamic signals at the proximal and distal ends of a welding area, calibrates the stiffness of an electrode pressurizing mechanism, then processes the dynamic signals to obtain a distal displacement signal and a proximal vibration signal, and performs vibration filtering on the distal displacement signal according to the proximal vibration signal to obtain a smooth electrode displacement signal with jitter eliminated, thereby avoiding the sensor installation interference problem that may occur when measuring the electrode displacement signal in the proximal welding area, while eliminating the displacement signal jitter problem caused by insufficient stiffness of the electrode pressurizing mechanism, and improving the accuracy of the distal measurement displacement signal; compared with the traditional measurement method that does not consider vibration filtering, the jitter degree of the displacement signal obtained by the present method is reduced by nearly 87%, which is extremely close to the high-precision measured displacement signal obtained by high-speed photography, and provides technical support for subsequent online monitoring of micro-resistance spot welding.

[0131] Those skilled in the art know that, in addition to realizing the system and its various devices, modules, and units provided by the present invention in a purely computer-readable program code, it is entirely possible to realize the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system and its various devices, modules, and units provided by the present invention can be considered as a hardware component, and the devices, modules, and units included therein for realizing various functions can also be regarded as structures within the hardware component; the devices, modules, and units for realizing various functions can also be regarded as both software modules for realizing the method and structures within the hardware component.

[0132] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A multi-sensor measurement method for displacement signals of large cantilever electrodes in micro-resistance spot welding, characterized in that: include: Step S1: collecting sensor data during the air compression process and calibrating the stiffness of the electrode pressurizing mechanism; Step S2: Perform sample welding and collect dynamic signals of the welding process; The dynamic signal includes an acceleration signal, a pressure signal and a displacement signal; Step S3: according to the stiffness of the electrode pressurizing mechanism, the acceleration signal, the pressure signal and the displacement signal are coupled to obtain a far-end displacement signal and a near-end vibration signal; Step S4: Use the proximal vibration signal to perform vibration filtering on the distal displacement signal to obtain a filtered electrode displacement signal, thereby completing the measurement process.

2. The multi-sensor measurement method for displacement signal of large cantilever electrode of micro-resistance spot welding according to claim 1 is characterized in that: The sensor comprises part or all of an upper electrode acceleration sensor (5), an upper electrode pressure sensor (6), an upper electrode displacement sensor (7), a lower electrode acceleration sensor (8), a lower electrode pressure sensor (9), and a lower electrode displacement sensor (10); the step S1 comprises setting multiple levels of electrode pressure for air compression, collecting and recording acceleration signals and pressure signals during the air compression process, and measuring the displacement of the electrode end at the same time; and calibrating the stiffness of the electrode pressurizing mechanism according to the following formula: v i (t)=∫a i (t)dt; F i (t)=k·S i (t)+ξ·v i (t)+m·a i (t) Among them, F i (t) and a i (t) are the pressure signal and acceleration signal of the air compression stage under different set pressures; S i (t) is the measured electrode end displacement signal in the air compression stage under different set pressures; v i (t) is the speed signal of the electrode end; i = 1, 2, 3, ..., n, representing the air pressure stage under different gear electrode pressures; k, ξ and m are the stiffness coefficients of the electrode pressurizing mechanism to be calibrated; The pressure signal, displacement signal and acceleration signal in the dynamic signal are coupled through the remote displacement signal operation process f1(·) to obtain the remote displacement signal S r The acceleration signal is processed through the near-end vibration signal operation process f2(·) to obtain the near-end vibration signal S v The far-end displacement signal and the near-end vibration signal are processed by the vibration filtering operation process f3(·) to obtain the electrode displacement signal S e ; When using different sensors for calculation, the calculation process f1(·)f2(·)f3(·) calculation,, The form changes.

3. The multi-sensor measurement method for displacement signal of large cantilever electrode of micro-resistance spot welding according to claim 2 is characterized in that: If an upper electrode displacement sensor (7), a lower electrode acceleration sensor (8) and a lower electrode pressure sensor (9) are used, the calculation formula of the remote displacement signal operation processing process f1(·) is: Among them, S r is the far-end displacement signal, a m is the acceleration signal collected by the lower electrode acceleration sensor (8), v m is the speed signal, S m is the displacement signal collected by the upper electrode displacement sensor (7), F is the pressure signal collected by the lower electrode pressure sensor (9), k, ξ and m are the stiffness of the electrode pressurizing mechanism; Acceleration signal a m The near-end vibration signal S is obtained through the near-end vibration signal calculation process f2(·) v : f2(·):S v =∫∫a m dt Far-end displacement signal S r and the near-end vibration signal S v The filtered electrode displacement signal S is obtained through the vibration filtering operation process f3(·) e : f3(·):S e =S r -S v 。 4. The multi-sensor measurement method for displacement signal of large cantilever electrode of micro-resistance spot welding according to claim 2 is characterized in that: If an upper electrode acceleration sensor (5), an upper electrode pressure sensor (6) and a lower electrode acceleration sensor (8) are used, the calculation formula of the remote displacement signal operation processing process f1(·) is: Among them, S r is the distal displacement signal, F is the pressure signal collected by the upper electrode pressure sensor (6), and k is the stiffness coefficient of the electrode pressurizing mechanism; The upper electrode acceleration signal a collected by the upper electrode acceleration sensor (5) m1 and the lower electrode acceleration signal a collected by the lower electrode acceleration sensor (8) m2 The near-end vibration signal S is obtained through the near-end vibration signal calculation process f2(·) v : Among them, v m1 is the velocity signal of the upper electrode, v m2 is the velocity signal of the lower electrode, k, ξ and m are the stiffness coefficients of the electrode pressing mechanism; Far-end displacement signal S r and the near-end vibration signal S v The filtered electrode displacement signal S is obtained through the vibration filtering operation process f3(·) e : f3(·):S e =S r -S v 。 5. The multi-sensor measurement method for displacement signal of large cantilever electrode of micro-resistance spot welding according to claim 2 is characterized in that: If an upper electrode acceleration sensor (5), an upper electrode displacement sensor (7), a lower electrode acceleration sensor (8) and a lower electrode displacement sensor (10) are used, the calculation formula of the remote displacement signal operation processing process f1(·) is: f1(·):S r =S m1 +S m2 Among them, S r is the distal displacement signal, S m1 is the upper electrode displacement signal collected by the upper electrode displacement sensor (7), S m2 is a lower electrode displacement signal collected by a lower electrode displacement sensor (10); The upper electrode acceleration signal a collected by the upper electrode acceleration sensor (5) m1 and the lower electrode acceleration signal a collected by the lower electrode acceleration sensor (8) m2 The near-end vibration signal S is obtained through the near-end vibration signal calculation process f2(·) v : f2(·):S v =∫∫a m1 dt+∫∫a m2 dt Far-end displacement signal S r and the near-end vibration signal S v The filtered electrode displacement signal S is obtained through the vibration filtering operation process f3(·) e : f3(·):S e =S r -S v 。 6. A multi-sensor measurement system for displacement signals of large cantilever electrodes for micro-resistance spot welding, characterized in that: include: An upper electrode (1), a lower electrode (2), an upper electrode cantilever (3), a lower electrode cantilever (4), an upper electrode acceleration sensor (5), an upper electrode pressure sensor (6), an upper electrode displacement sensor (7), a lower electrode acceleration sensor (8), a lower electrode pressure sensor (9), a lower electrode displacement sensor (10), a frame (11), a dynamic signal acquisition module (12), and a calculation and analysis module (13); The upper electrode acceleration sensor (5) is mounted on the upper electrode cantilever (3) and is used to collect the acceleration signal of the upper electrode (1); The upper electrode pressure sensor (6) is mounted on the upper electrode cantilever (3) and is used to obtain a pressure signal of the upper electrode (1); The upper electrode displacement sensor (7) is mounted on the frame (11) and is used to collect the displacement signal of the upper electrode (1); The lower electrode acceleration sensor (8) is mounted on the lower electrode cantilever (4) and is used to collect the acceleration signal of the lower electrode (2); The lower electrode pressure sensor (9) is mounted on the lower electrode cantilever (4) and is used to obtain a pressure signal of the lower electrode (2); The lower electrode displacement sensor (10) is mounted on the frame (11) and is used to collect the displacement signal of the lower electrode (2); Each sensor completes signal acquisition based on the dynamic signal acquisition module (12), and summarizes the data and sends it to the calculation and analysis module (13); The calculation and analysis module (13) receives and processes signal data and outputs calculation results.

7. The multi-sensor measurement system for displacement signals of large cantilever electrodes for micro-resistance spot welding according to claim 6, characterized in that: It includes setting multiple levels of electrode pressure for air compression, collecting and recording acceleration signals and pressure signals during the air compression process, and measuring the displacement of the electrode end; calibrating the stiffness of the electrode pressurizing mechanism according to the following formula: v i (t)=∫a i (t)dt; F i (t)=k·S i (t)+ξ·v i (t)+m·a i (t) Among them, F i (t) and a i (t) are the pressure signal and acceleration signal of the air compression stage under different set pressures; S i (t) is the measured electrode end displacement signal in the air compression stage under different set pressures; v i (t) is the speed signal of the electrode end; i = 1, 2, 3, ..., n, representing the air pressure stage under different gear electrode pressures; k, ξ and m are the stiffness coefficients of the electrode pressurizing mechanism to be calibrated; The pressure signal, displacement signal and acceleration signal in the dynamic signal are coupled through the remote displacement signal operation process f1(·) to obtain the remote displacement signal S r The acceleration signal is processed through the near-end vibration signal operation process f2(·) to obtain the near-end vibration signal S v The far-end displacement signal and the near-end vibration signal are processed by the vibration filtering operation process f3(·) to obtain the electrode displacement signal S e ; When using different sensors for calculation, the calculation process f1(·)f2(·)f3(·) calculation,, The form changes.

8. The multi-sensor measurement system for displacement signals of large cantilever electrodes for micro-resistance spot welding according to claim 6, characterized in that: If an upper electrode displacement sensor (7), a lower electrode acceleration sensor (8) and a lower electrode pressure sensor (9) are used, the calculation formula of the remote displacement signal operation processing process f1(·) is: Among them, S r is the far-end displacement signal, a m is the acceleration signal collected by the lower electrode acceleration sensor (8), v m is the speed signal, S m is the displacement signal collected by the upper electrode displacement sensor (7), F is the pressure signal collected by the lower electrode pressure sensor (9), k, ξ and m are the stiffness of the electrode pressurizing mechanism; Acceleration signal a m The near-end vibration signal S is obtained through the near-end vibration signal calculation process f2(·) v : f2(·):S v =∫∫a m dt Far-end displacement signal S r and the near-end vibration signal S v The filtered electrode displacement signal S is obtained through the vibration filtering operation process f3(·) e : f3(·):S e =S r -S v 。 9. The multi-sensor measurement system for displacement signals of large cantilever electrodes for micro-resistance spot welding according to claim 6, characterized in that: If an upper electrode acceleration sensor (5), an upper electrode pressure sensor (6) and a lower electrode acceleration sensor (8) are used, the calculation formula of the remote displacement signal operation processing process f1(·) is: Among them, S r is the distal displacement signal, F is the pressure signal collected by the upper electrode pressure sensor (6), and k is the stiffness coefficient of the electrode pressurizing mechanism; The upper electrode acceleration signal a collected by the upper electrode acceleration sensor (5) m1 and the lower electrode acceleration signal a collected by the lower electrode acceleration sensor (8) m2 The near-end vibration signal S is obtained through the near-end vibration signal calculation process f2(·) v : Among them, v m1 is the velocity signal of the upper electrode, v m2 is the velocity signal of the lower electrode, k, ξ and m are the stiffness coefficients of the electrode pressing mechanism; Far-end displacement signal S r and the near-end vibration signal S v The filtered electrode displacement signal S is obtained through the vibration filtering operation process f3(·) e : f3(·):S e =S r -S v 。 10. The multi-sensor measurement system for displacement signals of large cantilever electrodes for micro-resistance spot welding according to claim 6, characterized in that: If an upper electrode acceleration sensor (5), an upper electrode displacement sensor (7), a lower electrode acceleration sensor (8) and a lower electrode displacement sensor (10) are used, the calculation formula of the remote displacement signal operation processing process f1(·) is: f1(·):S r =S m1 +S m2 Among them, S r is the distal displacement signal, S m1 is the upper electrode displacement signal collected by the upper electrode displacement sensor (7), S m2 is a lower electrode displacement signal collected by a lower electrode displacement sensor (10); The upper electrode acceleration signal a collected by the upper electrode acceleration sensor (5) m1 and the lower electrode acceleration signal a collected by the lower electrode acceleration sensor (8) m2 The near-end vibration signal S is obtained through the near-end vibration signal calculation process f2(·) v : f2(·):S v =∫∫a m1 dt+∫∫a m2 dt Far-end displacement signal S r and the near-end vibration signal S v The filtered electrode displacement signal S is obtained through the vibration filtering operation process f3(·) e : f3(·):S e =S r -S v 。

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