High-precision measurement method for internal gap and infinitesimal displacement of closed area based on magnetic-force-sound coupling

Abstract

The invention discloses a high-precision measurement method for internal gaps and infinitesimal displacement of a closed area based on magnetic-force-sound coupling. The high-precision measurement method comprises the following steps that (1) a sensor module is installed at the tail end of an automatic scanning mechanical arm; (2) controlling the automatic scanning mechanical arm to move, so that the sensor module is close to the surface of the detected material, thereby detecting the magnetic acting force between the magnetic force detection probe (3) and the detected material, and calculating the vertical distance between the magnetic force detection probe (3) and the surface of the detected material; 3) synchronously measuring the film thickness T on the surface of the measured material by using an ultrasonic detection probe; and 4) based on the vertical distance between the magnetic detection probe (3) and the surface of the detected material and the thickness T of the film on the surface of the detected material, calculating the micro-gap between the film and the surface of the detected material. The detection signal is not influenced by factors such as environment temperature and material heat conductivity difference, and existence and specific size of the gap can be accurately detected.

Description

Technical Field

[0001] This invention relates to the field of displacement monitoring, specifically a high-precision method for measuring the internal gaps and minute displacements of a closed region using a "magnetic-force-acoustic" coupling mechanism. Background Technology

[0002] In aerospace, high-end manufacturing, and other fields, large composite material components (such as skins, beams, and compartments) are often laminated after molding to improve structural performance or impart functionality (such as corrosion protection and electromagnetic shielding). However, the "micro-gaps" created after lamination are extremely difficult to detect and can easily lead to decreased airtightness, interlayer delamination, or electrical performance failure. Therefore, accurate detection of these micro-gaps is crucial.

[0003] Currently, the existing measurement methods for mold gap issues arising during the assembly of large composite components fall into two main categories: contact and non-contact. Contact measuring tools, such as mechanical probes and micrometers, measure gaps by directly contacting the object being measured. This type of method only supports static measurements and is prone to significant human error. Non-contact measuring tools include laser displacement sensors and capacitive sensors. Laser displacement sensors calculate distances based on the laser reflection time / phase difference, but the laser is susceptible to reflection and high temperatures. Capacitive sensors reflect changes in gap size by detecting changes in capacitance, but they are easily affected by material properties and environmental sensitivity, and are highly dependent on installation accuracy.

[0004] Existing composite material skin bonding gap detection devices and methods, such as gap measurement using single-point capacitive sensors, can only acquire gap data at a single point and cannot reflect the overall morphology of the measured surface, resulting in local measurement limitations.

[0005] Ultrasonic and eddy current technologies are ineffective in detecting high-damping layers or composites with low conductivity (such as CFRP / carbon fiber reinforced plastics). Thermal imaging relies on temperature difference imaging, which is easily affected by ambient temperature and differences in material thermal conductivity, leading to false positives or false negatives. Most detection technologies are biased towards qualitative judgments of "whether there is a defect," lacking precise quantitative methods for the width, depth, and location of micro-gaps. Variables such as thermal pressure and adhesive diffusion generated during film application introduce interfacial microvoids, but existing models do not fully consider the impact of these factors on the detection signal.

[0006] In summary, most existing methods suffer from limitations such as high measurement costs, limited applicability, and inability to perform online monitoring. In practical engineering applications, the strong structural enclosure, limited measurement area, and the need for large-area, high-resolution measurements make it difficult for traditional methods to meet the requirements for efficient and accurate evaluation of molding quality. Summary of the Invention

[0007] The purpose of this invention is to provide a high-precision method for measuring the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling, comprising the following steps:

[0008] 1) The sensor module is installed at the end of the automated scanning robotic arm. The sensor module includes a pressure sensor, a magnetic detection probe, and an ultrasonic detection probe.

[0009] 2) Control the movement of the automatic scanning robotic arm to bring the sensor module close to the surface of the material being tested, thereby detecting the magnetic force between the magnetic detection probe and the material being tested, and calculating the vertical distance between the magnetic detection probe and the surface of the material being tested.

[0010] 3) Use an ultrasonic testing probe to simultaneously measure the film thickness T on the surface of the material being tested.

[0011] 4) Calculate the micro-gap between the magnetic detection probe and the surface of the material being tested, based on the vertical distance between the magnetic detection probe and the surface of the material being tested, and the film thickness T on the surface of the material being tested.

[0012] Furthermore, the structure of the sensor module can be any of the following:

[0013] Structure 1: The pressure sensor, magnetic detection probe, and ultrasonic detection probe are arranged from top to bottom. The pressure sensor and magnetic sensor are directly connected, and the ultrasonic detection probe is placed below the magnetic detection probe.

[0014] Structure 2: The pressure sensor is connected only to the magnetic force detection probe. The magnetic force detection probe and the ultrasonic detection probe are arranged in parallel.

[0015] Structure 3: The pressure sensor is only connected to the ultrasonic testing probe. The magnetic testing probe is ring-shaped and surrounds the ultrasonic testing probe.

[0016] Furthermore, the step of calculating the perpendicular distance between the magnetic detection probe and the surface of the material being measured includes:

[0017] 2.1) Use a magnetic force detection probe to detect the magnetic force F(D) between the magnetic force detection probe and the material being tested.

[0018] 2.2) Convert the magnetic force F(D) into an electrical signal U, that is:

[0019] U=S·F(D) (1)

[0020] Where U is the voltage or current signal output by the pressure sensor, and S is the sensitivity coefficient of the pressure sensor.

[0021] 2.3) Calculate the perpendicular distance D between the magnetic detection probe and the surface of the material being measured, i.e.:

[0022]

[0023] In the formula, M is the magnetic moment of the magnet. μ is the relative permeability of the material being measured. n is the attenuation exponent. k is the proportionality coefficient.

[0024] Furthermore, the film thickness T on the surface of the tested material is shown below:

[0025]

[0026] Where Δt is the round-trip propagation time of the ultrasonic wave from the probe's emission to the received echo, and v is the propagation speed of the ultrasonic wave in the material being tested.

[0027] Furthermore, the steps for calculating the micro-gap between the film and the surface of the test material include:

[0028] 4.1) Calculate the distance measurement error δ D ,Right now:

[0029]

[0030] Where, δ D This represents the distance measurement error. δ U This represents the measurement error of the pressure sensor output signal. δ U The results are obtained through experimental calibration, that is, the output characteristics of the sensor are calibrated under known force standard conditions, and the measurement noise and uncertainty are statistically analyzed.

[0031] 4.2) Calculate the ultrasonic thickness measurement error δ T ,Right now:

[0032]

[0033] Where, δ T This represents the thickness measurement error. δ v This represents the error in sound speed. δ Δt This represents the time measurement error. The sound velocity error δ v The time measurement error δ was obtained through standard thickness sample experiment calibration and temperature coefficient correction. T The value is determined by the sampling system resolution and experimental repeatability tests.

[0034] 4.3) Calculate the thickness measurement error δ caused by sensor position deviation. position ,Right now:

[0035] δ position =S·Δx (6)

[0036]

[0037] In the formula, S is the ratio of the film thickness T on the surface of the measured material to the change in position. x is the scanning position coordinate along the surface of the component. Δx is the position deviation value, that is, the position difference of the sensor module from the preset path.

[0038] 4.4) Calculate the total measurement error, i.e.:

[0039]

[0040] Where, δ total This represents the total error. δ D This represents the error in magnetic distance measurement. δ T This represents the error in ultrasonic thickness measurement. δ position This is the error caused by positional deviation.

[0041] 4.5) Calculate the initial micro-gap X between the film and the surface of the material being tested, i.e.:

[0042] X = DT(9)

[0043] 4.6) Correct the initial micro-gap X to obtain the micro-gap between the film and the surface of the tested material, i.e.:

[0044] X'=X-δ position (10)

[0045] 4.7) Determine the uncertainty X′±δ of the microgap X' total If the engineering requirements are met, output the micro-gap X'.

[0046] Furthermore, if the uncertainty of the micro-gap X' is X′±δ total If the project requirements are not met, proceed with the following steps:

[0047] S1) Repeat the measurement of the micro gap X' to eliminate occasional noise or single-point measurement abnormalities. If the micro gap X' still does not meet the engineering requirements after repeated measurement, proceed to step S2).

[0048] S2) will δ total Disassembled into δ D δ T With δ position The process consists of three parts: by comparing calibration data, it is determined whether the error is due to the accumulation of errors in the measurement system itself. If so, the error is reduced by recalibrating and correcting, and the micro-gap X' is recalculated. If the recalculated micro-gap X' still does not meet the engineering requirements, then proceed to step S3.

[0049] S3) If the workpiece film quality is found to be defective, an inspection report is automatically generated and the workpiece model, batch number and defect location are recorded in the database.

[0050] A high-precision method for measuring the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling includes the following steps:

[0051] 1) Install a sensor module on each of the multiple joints of the multi-head rotating disc.

[0052] 2) The system performs a power-on self-test and initializes the robot arm's zero point and the status of each sensor.

[0053] 3) The operator inputs the workpiece model, scanning area, and error threshold on the host computer.

[0054] 4) The robotic arm is automatically scanned into position and moves to the starting point according to a preset path. The workpiece coordinate system is corrected using laser or vision positioning.

[0055] 5) Start the sensors. The magnetic probe, pressure sensor, and ultrasonic probe are powered on and complete self-test and zero-point calibration.

[0056] 6) Control the movement of the automatic scanning robotic arm to bring the sensor module close to the surface of the material being tested, thereby detecting the magnetic force between the magnetic detection probe and the material, and calculating the vertical distance D between the magnetic detection probe and the surface of the material, i.e.:

[0057]

[0058] In the formula, U is the voltage or current signal output by the pressure sensor. S is the sensitivity coefficient of the pressure sensor. M is the magnetic moment intensity of the magnet. μ is the relative permeability of the measured material. n is the attenuation exponent. k is the proportionality coefficient.

[0059] 7) Simultaneously measure the film thickness T on the surface of the material being tested using an ultrasonic testing probe, i.e.:

[0060]

[0061] Where Δt is the round-trip propagation time of the ultrasonic wave from the probe's emission to the received echo, and v is the propagation speed of the ultrasonic wave in the material being tested.

[0062] 8) The vertical distance between the magnetic force detection probe and the surface of the material being tested, and the film thickness T on the surface of the material being tested are sent to the controller via a high-speed bus, with a timestamp to ensure synchronization.

[0063] 9) Calculate the micro-gap X = DT between the film and the surface of the material being tested in real time.

[0064] 10) Calculate the compensation term δ based on the thickness gradient s = dT / dx and the probe displacement Δx. position The micro-gap X is then corrected to obtain the precise gap value X′=X–δ position .

[0065] Furthermore, after obtaining the precise gap value, the following steps are performed:

[0066] 11) Generate micro-gap distribution data, map the precise gap value X′ to the workpiece coordinates in real time, and generate a heat map or contour grid.

[0067] 12) Data storage and analysis: Measurement data, equipment ID, and batch number are written to the database. The background system analyzes anomalies and calculates the pass rate.

[0068] 13) Automatically generate test reports.

[0069] 14) Once the measurement is complete, the system will issue a "Measurement Complete" signal for subsequent processes to use.

[0070] 15) The robotic arm returns to its original position, executing a zero-return or standby posture. The probe power is turned off, and the safety cover is retracted.

[0071] 16) Log archiving: If no abnormalities are found, the system enters standby mode. If a fault code is detected, it will automatically prompt maintenance personnel for handling.

[0072] Furthermore, when installing a sensor module on each of the multiple joints of the multi-head rotating disk, the following constraints must be followed:

[0073] Constraint 1: The structure of the sensor module installed at each connector may be the same as or different from the structure of the sensor module installed at other connectors.

[0074] Constraint 2: The total number of pressure sensors, magnetic detection probes, and ultrasonic detection probes installed on the multi-head rotating disc must be at least 1.

[0075] Constraint 3: At least one pressure sensor is connected to a magnetic force detection probe or an ultrasonic detection probe.

[0076] Constraint 4: The sensor module structure can be any of the following:

[0077] Structure 1: Includes a pressure sensor, a magnetic detection probe, and an ultrasonic detection probe arranged from top to bottom. The pressure sensor and the magnetic sensor are directly connected, and the ultrasonic detection probe is placed below the magnetic detection probe.

[0078] Structure 2: Includes a pressure sensor, a magnetic detection probe, an ultrasonic detection probe, and an ultrasonic detection probe arranged in parallel from top to bottom. The pressure sensor is connected to the magnetic detection probe.

[0079] Structure 3: Includes a pressure sensor and a nested detection probe arranged from top to bottom. The nested detection probe includes an ultrasonic detection probe and a ring-shaped magnetic detection probe surrounding the ultrasonic detection probe. The pressure sensor is connected to the ultrasonic detection probe.

[0080] Structure 4 includes a pressure sensor and an ultrasonic testing probe that are interconnected, as well as a magnetic testing probe that is connected to or arranged independently of the ultrasonic testing probe.

[0081] The technical effects of this invention are undeniable, and its beneficial effects are as follows:

[0082] 1) This invention provides a micro-gap detection device and method for large composite skin structures, which significantly improves detection accuracy and effectively solves the problem that traditional methods are difficult to measure accurately;

[0083] 2) The gap detection device provided by this invention improves detection efficiency by innovatively combining magnetic force detection and ultrasonic detection. It can realize automated, rapid scanning and data analysis, and is suitable for batch detection of large-scale components; it reduces human error and ensures the consistency and reliability of detection results.

[0084] 3) It features multiple replaceable magnetic detection modules, allowing for flexible selection of the required module based on the required detection accuracy and the specific composite material being tested. It offers high flexibility, is suitable for composite components with various complex surface shapes, and has strong scalability.

[0085] In summary, the gap detection device proposed in this invention overcomes the influence of high-damping layers or low-conductivity composites (such as CFRP / carbon fiber reinforced plastic) films on detection. It is unaffected by factors such as ambient temperature and differences in material thermal conductivity on the detection signal, and can accurately detect the existence and specific size of gaps. The changes in gaps or film thickness can effectively quantify the minute relative displacements / deformations generated inside or at the interface of the tested component. Attached Figure Description

[0086] Figure 1 Overall structural diagram of an automated device for measuring micro-gap in the molding process of large composite components;

[0087] Figure 2 A schematic diagram showing the magnetic force and probe distance for measuring the micro-gap of a large composite component after molding;

[0088] Figure 3 Diagram of a multi-head automated sensor for micro-gap measurement;

[0089] Figure 4 A schematic diagram illustrating the principle of micro-gap detection after film is applied to the molding of large composite components.

[0090] Figure 5Flowchart of a method for detecting micro-gaps in film-coated large composite components after molding;

[0091] In the diagram, there is a threaded connection A, a pressure sensor 1, a magnetic detection probe 3, and an ultrasonic detection probe 2. Detailed Implementation

[0092] The present invention will be further described below with reference to embodiments, but it should not be construed that the scope of the present invention is limited to the following embodiments. Various substitutions and modifications made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention should be included within the scope of protection of the present invention.

[0093] Example 1:

[0094] A high-precision method for measuring the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling includes the following steps:

[0095] 1) The sensor module is installed at the end of the automatic scanning robotic arm. The sensor module includes a pressure sensor 1, a magnetic detection probe 3, and an ultrasonic detection probe 2.

[0096] 2) Control the movement of the automatic scanning robotic arm to bring the sensor module close to the surface of the material being tested, thereby detecting the magnetic force between the magnetic detection probe 3 and the material being tested, and calculating the vertical distance between the magnetic detection probe 3 and the surface of the material being tested.

[0097] 3) Use an ultrasonic testing probe to simultaneously measure the film thickness T on the surface of the material being tested.

[0098] 4) Based on the vertical distance between the magnetic detection probe 3 and the surface of the material being tested, and the film thickness T on the surface of the material being tested, calculate the micro gap between the film and the surface of the material being tested.

[0099] Example 2:

[0100] A high-precision measurement method for the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling, with the same technical content as in Embodiment 1, further wherein the structure of the sensor module is any one of the following:

[0101] Structure 1: Pressure sensor 1, magnetic detection probe 3, and ultrasonic detection probe 2 are arranged in order from top to bottom. Among them, pressure sensor 1 is directly connected to magnetic sensor, and ultrasonic detection probe 2 is placed below magnetic detection probe 3.

[0102] Structure 2: Pressure sensor 1 is connected only to magnetic detection probe 3 (threaded connection, denoted as A). Magnetic detection probe 3 and ultrasonic detection probe 2 are arranged in parallel.

[0103] Structure 3: The pressure sensor is only connected to the ultrasonic testing probe. The magnetic testing probe 3 is ring-shaped and surrounds the ultrasonic testing probe 2.

[0104] Example 3:

[0105] A high-precision measurement method for the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling, with the same technical content as any one of Embodiments 1-2, further comprising the step of calculating the perpendicular distance between the magnetic force detection probe 3 and the surface of the material being measured, including:

[0106] 2.1) Use the magnetic force detection probe 3 to detect the magnetic force F(D) between the magnetic force detection probe 3 and the material being tested.

[0107] 2.2) Convert the magnetic force F(D) into an electrical signal U, that is:

[0108] U=S·F(D) (1)

[0109] Where U is the voltage or current signal output by pressure sensor 1. S is the sensitivity coefficient of pressure sensor 1.

[0110] 2.3) Calculate the perpendicular distance D between the magnetic detection probe 3 and the surface of the material being measured, i.e.:

[0111]

[0112] In the formula, M is the magnetic moment of the magnet. μ is the relative permeability of the material being measured. n is the attenuation exponent. k is the proportionality coefficient.

[0113] Example 4:

[0114] A high-precision measurement method for the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling, with the same technical content as any one of embodiments 1-3, further wherein the film thickness T on the surface of the material being measured is as follows:

[0115]

[0116] Where Δt is the round-trip propagation time of the ultrasonic wave from the probe's emission to the received echo, and v is the propagation speed of the ultrasonic wave in the material being tested.

[0117] Example 5:

[0118] A high-precision method for measuring the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling, with the same technical content as any one of embodiments 1-4, further comprising the following steps for calculating the micro-gap between the film and the surface of the material being measured:

[0119] 4.1) Calculate the distance measurement error δ D ,Right now:

[0120]

[0121] Where, δ D This represents the distance measurement error. δ U The measurement error is represented by the output signal of pressure sensor 1. δ U The results are obtained through experimental calibration, that is, the output characteristics of the sensor are calibrated under known force standard conditions, and the measurement noise and uncertainty are statistically analyzed.

[0122] 4.2) Calculate the ultrasonic thickness measurement error δ T ,Right now:

[0123]

[0124] Where, δ T This represents the thickness measurement error. δ v This represents the error in sound speed. δ Δt This represents the time measurement error. The sound velocity error is v. v The time measurement error δ was obtained through standard thickness sample experiment calibration and temperature coefficient correction. T The value is determined by the sampling system resolution and experimental repeatability tests.

[0125] 4.3) Calculate the thickness measurement error δ caused by sensor position deviation. position ,Right now:

[0126] δ position =S·Δx (6)

[0127]

[0128] In the formula, S is the ratio of the film thickness T on the surface of the measured material to the change in position. x is the scanning position coordinate along the surface of the component. Δx is the position deviation value, that is, the position difference of the sensor module from the preset path.

[0129] 4.4) Calculate the total measurement error, i.e.:

[0130]

[0131] Where, δ total This represents the total error. δ D This represents the error in magnetic distance measurement. δ T This represents the error in ultrasonic thickness measurement. δ position This is the error caused by positional deviation.

[0132] 4.5) Calculate the initial micro-gap X between the film and the surface of the material being tested, i.e.:

[0133] X = DT(9)

[0134] 4.6) Correct the initial micro-gap X to obtain the micro-gap between the film and the surface of the tested material, i.e.:

[0135] X'=X-δ position (10)

[0136] 4.7) Determine the uncertainty X′±δ of the microgap X' total Does it meet the engineering requirements (X′±δ)? total Whether it falls within the preset range, or whether X′ is located at X. ref ±δ total Within the range, X ref If the preset reference value is used, then the micro-gap X' is output.

[0137] Example 6:

[0138] A high-precision measurement method for the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling, with technical content identical to any one of embodiments 1-5, further wherein the uncertainty of the minute gap X' is X′±δ total If the project requirements are not met, proceed with the following steps:

[0139] Measurement results confirmed

[0140] The system first performs repeated measurements on X', combining data from different scanning positions and multiple samplings to eliminate sporadic noise or single-point measurement anomalies.

[0141] At the same time, the built-in zero-point calibration and calibration program is invoked to quickly verify the pressure sensor sensitivity, ultrasonic velocity correction parameters, and robotic arm path deviation.

[0142] Error component analysis

[0143] δ total Disassembled into δ D δ T With δ position The process involves three parts: comparing calibration data to determine whether the error is due to the accumulation of errors in the measurement system itself; if so, recalibration and correction are prioritized to reduce the error.

[0144] Engineering disposal

[0145] If X'±δ still exists after retesting and calibration total If the value exceeds the preset threshold, it is determined that there is a defect in the quality of the film applied to the workpiece.

[0146] At this point, the system will automatically generate an inspection report and record the workpiece model, batch number, and defect location in the database. The operator can then perform subsequent rework processes based on the report results, such as local repressurization, hot-press curing, or re-applying the film.

[0147] Example 7:

[0148] A high-precision method for measuring the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling includes the following steps:

[0149] 1) Install a sensor module on each of the multiple joints of the multi-head rotating disc 7.

[0150] 2) The system performs a power-on self-test and initializes the robot arm's zero point and the status of each sensor.

[0151] 3) The operator inputs the workpiece model, scanning area, and error threshold on the host computer.

[0152] 4) The robotic arm is automatically scanned into position and moves to the starting point according to a preset path. The workpiece coordinate system is corrected using laser or vision positioning.

[0153] 5) Start the sensors. Power on the magnetic probe, pressure sensor 1, and ultrasonic probe and complete self-test and zero-point calibration.

[0154] 6) Control the movement of the automatic scanning robotic arm to bring the sensor module close to the surface of the material being tested, thereby detecting the magnetic force between the magnetic detection probe 3 and the material being tested, and calculating the perpendicular distance D between the magnetic detection probe 3 and the surface of the material being tested, i.e.:

[0155]

[0156] In the formula, U is the voltage or current signal output by pressure sensor 1. S is the sensitivity coefficient of pressure sensor 1. M is the magnetic moment intensity of the magnet. μ is the relative permeability of the measured material. n is the attenuation exponent. k is the proportionality coefficient.

[0157] 7) Simultaneously measure the film thickness T on the surface of the material being tested using an ultrasonic testing probe, i.e.:

[0158]

[0159] Where Δt is the round-trip propagation time of the ultrasonic wave from the probe's emission to the received echo, and v is the propagation speed of the ultrasonic wave in the material being tested.

[0160] 8) The vertical distance between the magnetic force detection probe 3 and the surface of the material being tested, and the film thickness T on the surface of the material being tested are sent to the controller via a high-speed bus, with a timestamp to ensure synchronization.

[0161] 9) Calculate the micro-gap X = DT between the film and the surface of the material being tested in real time.

[0162] 10) Calculate the compensation term δ based on the thickness gradient s = dT / dx and the probe displacement Δx. position The micro-gap X is then corrected to obtain the precise gap value X′=X–δposition .

[0163] Example 8:

[0164] A high-precision measurement method for the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling, with the same technical content as in Embodiment 7, further comprising the following steps after obtaining the precise gap value:

[0165] 11) Generate micro-gap distribution data, map the precise gap value X′ to the workpiece coordinates in real time, and generate a heat map or contour grid.

[0166] 12) Data storage and analysis: Measurement data, equipment ID, and batch number are written to the database. The background system analyzes anomalies and calculates the pass rate.

[0167] 13) Automatically generate test reports.

[0168] 14) Once the measurement is complete, the system will issue a "Measurement Complete" signal for subsequent processes to use.

[0169] 15) The robotic arm returns to its original position, executing a zero-return or standby posture. The probe power is turned off, and the safety cover is retracted.

[0170] 16) Log archiving: If no abnormalities are found, the system enters standby mode. If a fault code is detected, it will automatically prompt maintenance personnel for handling.

[0171] Example 9:

[0172] A high-precision measurement method for the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling, with the same technical content as any one of embodiments 7-8, further wherein when a sensor module is installed on each of the multiple joints of the multi-head rotating disk 7, the following constraints are followed:

[0173] Constraint 1: The structure of the sensor module installed at each connector may be the same as or different from the structure of the sensor module installed at other connectors.

[0174] Constraint 2: The total number of pressure sensors 1 installed on the multi-head rotating disc 7 shall be at least 1, the total number of magnetic detection probes 3 shall be at least 1, and the total number of ultrasonic detection probes 2 shall be at least 1.

[0175] Constraint 3: At least one pressure sensor 1 is connected to either a magnetic force detection probe 3 or an ultrasonic detection probe 2.

[0176] Constraint 4: The sensor module structure can be any of the following:

[0177] Structure 1: Includes a pressure sensor 1, a magnetic detection probe 3, and an ultrasonic detection probe 2 arranged from top to bottom. The pressure sensor 1 is directly connected to the magnetic sensor, and the ultrasonic detection probe 2 is positioned below the magnetic detection probe 3.

[0178] Structure 2: Includes a pressure sensor 1, a magnetic detection probe 3, an ultrasonic detection probe 2 arranged from top to bottom, and an ultrasonic detection probe 2 arranged parallel to the magnetic detection probe 3. The pressure sensor 1 is connected to the magnetic detection probe 3.

[0179] Structure 3 includes a pressure sensor 1 and a nested detection probe arranged from top to bottom. The nested detection probe includes an ultrasonic detection probe 2 and a magnetic detection probe 3 that surrounds the ultrasonic detection probe 2 in a ring shape. The pressure sensor 1 is connected to the ultrasonic detection probe 2.

[0180] Structure 4 includes a pressure sensor 1 and an ultrasonic testing probe 2 that are interconnected, and a magnetic testing probe 3 that is connected to or arranged independently of the ultrasonic testing probe 2.

[0181] Example 10:

[0182] A high-precision measurement method for the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling, with the same technical content as any one of embodiments 7-9, further comprising: after calculating the minute gap X', determining whether the minute gap X' is located within the confidence interval X′±δ total If yes, then the engineering requirements are met; otherwise, the engineering requirements are not met.

[0183] Total error δ total As shown below:

[0184]

[0185] Where, δ total This represents the total error. δ D This represents the error in magnetic distance measurement. δ T This represents the error in ultrasonic thickness measurement. δ position This is the error caused by positional deviation.

[0186] Example 11:

[0187] A high-precision method for measuring the internal gaps and minute displacements of a closed region using a "magnetic-force-acoustic" coupling method is described below:

[0188] Mechanical components and connections include, but are not limited to:

[0189] Structure 1: The main structure of the sensor, from top to bottom, consists of a pressure sensor, a magnetic detection probe, and an ultrasonic detection probe. The pressure sensor and the magnetic sensor are directly connected, while the ultrasonic sensor is located below the magnetic sensor.

[0190] Structure 2: The main structure of the sensor, from top to bottom, includes: a pressure sensor, a magnetic detection probe, and an ultrasonic detection probe. The pressure sensor is only connected to the magnetic detection probe. Of the two detection probes, the magnetic detection probe and the ultrasonic detection probe are arranged in parallel and are mounted together at the end of the automatic scanning robotic arm.

[0191] Structure 3: The main structure of the sensor, from top to bottom, includes: a pressure sensor, a ring-shaped magnetic detection probe, and an ultrasonic detection probe. The pressure sensor is only connected to the ultrasonic detection probe; the two probes are nested, with the ultrasonic detection probe as the main component and the ring-shaped magnetic detection probe encircling the outside of it.

[0192] Structure 4 is based on a multi-head rotating disk. The connector below the disk is arranged with magnetic detection modules of varying magnetic strengths, including but not limited to those found in Structure 1, Structure 2, and Structure 3, or where the magnetic and ultrasonic modules are placed on different heads. This enables fully automatic switching across all scenarios.

[0193] Gap detection working principle and method:

[0194] The core measurement principle of this invention is the combined application of magnetic detection and ultrasonic measurement technologies.

[0195] Taking structure 1 as an example, the gap measurement principle of this invention will be described in detail below.

[0196] Step 1: Magnetic Detection and Distance Measurement. Large composite material components have a certain magnetic permeability. A magnet is installed inside the magnetic detection probe. When the probe approaches the surface of the material being measured, a change in the magnetic field is generated. The change in distance between the probe and the material causes a change in the magnetic field strength. A pressure sensor on the probe can further quantify the change in magnetic force. Based on a pre-calibrated formula relating magnetic field strength to distance, the distance D between the probe and the surface of the component mold is calculated in real time, with a nominal accuracy of δ. D mm.

[0197] The specific principle of distance measurement using pressure sensors and magnetic modules is as follows:

[0198] The relationship between magnetic force and distance is shown in the attached figure. Figure 2 The diagram shows the change in magnetic force and the test curve of the probe distance according to this invention. The general mathematical relationship (approximate model) of the interaction force (magnetic attraction or repulsion) between the magnet and the material under test as a function of distance is as follows:

[0199]

[0200] Where F(D) is the magnetic force between the magnet and the material being measured (Newtons, N). k is the proportionality constant, which depends on the magnet's geometry, magnetic field characteristics, and the material's permeability (dimensionless). M is the magnetic moment of the magnet (Ampere-square meter, A·m).2 μ is the relative permeability of the material being tested (dimensionless). D is the distance between the magnet and the material being tested (meters, m). n is the attenuation exponent, typically between 2 and 4, depending on the spatial geometry of the magnet and the material (typical values: n = 2, 4).

[0201] In practical applications, the above parameters (k, M, μ, n) are determined through experimental calibration to form a calibration curve.

[0202] The mechanical quantity F(D) detected by the pressure sensor is converted into an electrical signal U, expressed as:

[0203] U=S·F(D) (2)

[0204] Where U is the voltage or current signal output by the pressure sensor. S is the sensitivity coefficient of the pressure sensor (e.g., mV / N or mA / N).

[0205] From this, the mathematical formula for the magnetic force-distance relationship can be derived:

[0206]

[0207] Where D is the distance from the magnetic module to the test block.

[0208] Measurement accuracy and error analysis, measurement error δ D It can be determined through the error propagation formula:

[0209]

[0210] Where, δ D For distance measurement error; δ U The pressure sensor output signal measurement error.

[0211] Step 2: Ultrasonic measurement. An ultrasonic testing probe, arranged parallel to the magnetic probe, synchronously measures the thickness T of the film on the composite material surface. The ultrasonic sensor, based on the principle of ultrasonic wave reflection within the material, measures the film thickness T with a nominal accuracy of δ. T mm, the specific principle is as follows: Equation 5 and Equation 6.

[0212]

[0213] Where T is the thickness of the material being measured, and v is the round-trip propagation time of the ultrasonic wave from the probe's emission to the received echo.

[0214] In the error analysis of ultrasonic thickness measurement, the error δ in thickness measurement is... T Mainly affected by sound speed measurement error (δ) v ) and time measurement error (δ Δt )Influence:

[0215]

[0216] Where, δ T For thickness measurement error; δ v For sound speed error; δ Δt This represents the time measurement error.

[0217] Step 3: Micro-gap calculation. The actual gap X between the film and the mold under test is calculated using real-time data obtained from the two sensors mentioned above. The formula is:

[0218] X = DT(7)

[0219] Where X: the actual micro-gap between the film and the composite component (usually in millimeters or micrometers); if X≠0, it indicates the presence of a gap. D: the total distance between the film surface and the reference point (such as a sensor), measured by the sensor. T: the thickness of the composite component surface from the reference point, also obtained through ultrasonic or other measurement methods.

[0220] Step 4: Position error compensation. During actual measurement, there may be some deviation between the magnetic force and the ultrasonic probe position, leading to additional errors. The ratio of the component surface thickness to its position is defined as:

[0221]

[0222] Where S is the thickness change rate, that is, the rate at which the component thickness T changes with position x. T is the thickness of the component at different positions. x is the scanning position coordinate along the surface of the component.

[0223] This thickness change rate is used for position error compensation, as shown in the attached figure. Figure 4 As shown, the error caused by positional deviation is defined as:

[0224] δ position =S·Δx(9)

[0225] Where, δ position This represents the thickness measurement error caused by sensor position deviation. Δx is the position deviation value, i.e., the position difference of the sensor probe from the preset path. S is the aforementioned thickness change rate.

[0226] Step 7: Total Error Calculation. Taking into account all the errors mentioned above, the formula for calculating the total measurement error is:

[0227]

[0228] Where, δ total This represents the total error. δ D This represents the error in magnetic distance measurement. δ T This represents the error in ultrasonic thickness measurement. δposition This is the error caused by positional deviation.

[0229] Automated workflow of gap detection device:

[0230] The core application scenario of this invention is the application prospect of fully automated measurement in all scenarios.

[0231] Taking structure 4 as an example, the principle of automated gap measurement of this invention will be described in detail below. A specific flowchart is attached. Figure 5 As shown.

[0232] Step 1: Start the test. The system powers on and performs a self-test, initializing the robotic arm's zero point and the status of each sensor.

[0233] Step 2: Parameter input. The operator inputs task parameters such as workpiece model, scanning area, and error threshold on the host computer.

[0234] Step 3: The robotic arm is automatically scanned into position and moves to the starting point according to the preset path; the workpiece coordinate system is corrected using laser or vision positioning.

[0235] Step 4: Power on the sensors, including the magnetic probe, pressure sensor, and ultrasonic probe, and complete self-test and zero-point calibration.

[0236] Step 5: Pressure-magnetic linkage distance measurement (D), the probe is close to the workpiece surface; the pressure sensor converts the magnetic attraction into a force signal, and the probe-mold distance D is calculated in real time through the calibration curve.

[0237] Step 6: Ultrasonic measurement of film thickness (T). The ultrasonic probe synchronously emits pulses and measures the echo time difference Δt; calculate the film thickness T according to the formula T=v·Δt / 2.

[0238] Step 7: Real-time data transmission. D and T data are sent to the controller via a high-speed bus, with timestamps to ensure synchronization.

[0239] Step 8: Calculate the micro gap (X = D – T) in real time. The controller completes the subtraction operation within a millisecond period to obtain the original gap value X.

[0240] Step 9: Automatic position error compensation. Calculate the compensation term δ based on the thickness gradient s = dT / dx and the probe displacement Δx. position After correction, the precise gap value X′=X–δ is obtained. position .

[0241] Step 10: Generate micro-gap distribution data, map X′ to workpiece coordinates in real time, and generate a heat map or contour grid.

[0242] Step 11: Data storage and analysis. Measurement data, device ID, and batch number are written to the database; the background system counts anomalies and calculates the pass rate.

[0243] Step 12: Automatically generate the test report.

[0244] Step 13: Measurement complete. The system issues a "Measurement complete" signal for subsequent processes to use.

[0245] Step 14: The robotic arm returns to its original position and performs a zero-return or standby posture; the probe power is turned off and the safety cover is retracted.

[0246] Step 15: End, archive logs, and if there are no abnormalities, the system will enter standby mode; if a fault code is detected, it will automatically prompt the operation and maintenance department for handling.

Claims

1. A method for high-precision measurement of the internal gap and micro-displacement in a closed area with "magnetic-force-acoustic" coupling, characterized in that, The method comprises the following steps: 1) installing a sensor module at the end of an automatic scanning mechanical arm; the sensor module comprises a pressure sensor (1), a magnetic force detection probe (3), and an ultrasonic detection probe (2); 2) controlling the automatic scanning mechanical arm to move so that the sensor module is close to the surface of the measured material, thereby detecting the magnetic force between the magnetic force detection probe (3) and the measured material and calculating the vertical distance between the magnetic force detection probe (3) and the surface of the measured material; 3) synchronously measuring the film thickness T on the surface of the measured material by using the ultrasonic detection probe; 4) calculating the micro-gap between the film and the surface of the measured material based on the vertical distance between the magnetic force detection probe (3) and the surface of the measured material and the film thickness T on the surface of the measured material.

2. The method for high-precision measurement of internal gaps and minute displacements in a closed region using "magnetic-force-acoustic" coupling as described in claim 1, characterized in that... The structure of the sensor module is any one of the following structures: Structure one: the pressure sensor (1), the magnetic force detection probe (3), and the ultrasonic detection probe (2) are arranged from top to bottom in sequence; the pressure sensor (1) is directly connected with the magnetic force sensor, and the ultrasonic detection probe (2) is arranged below the magnetic force detection probe (3); Structure two: the pressure sensor (1) is connected only with the magnetic force detection probe (3); the magnetic force detection probe (3) and the ultrasonic detection probe (2) are arranged in parallel; Structure three: the pressure sensor is connected only with the ultrasonic detection probe; the magnetic force detection probe (3) is annular and surrounds the ultrasonic detection probe (2) externally.

3. The method for high-precision measurement of internal gaps and minute displacements in a closed region using "magnetic-force-acoustic" coupling as described in claim 1, characterized in that... The step of calculating the vertical distance between the magnetic force detection probe (3) and the surface of the measured material comprises the following steps: 2.1) detecting the magnetic force F(D) between the magnetic force detection probe (3) and the measured material by using the magnetic force detection probe (3); 2.2) converting the magnetic force F(D) into an electric signal U, namely: U=S·F(D) (1) wherein U is the voltage or current signal output by the pressure sensor (1); and S is the sensitivity coefficient of the pressure sensor (1); 2.3) calculating the vertical distance D between the magnetic force detection probe (3) and the surface of the measured material, namely: wherein M is the magnetic moment strength of the magnet; μ is the relative magnetic permeability of the measured material; n is the attenuation index; and k is the proportional coefficient.

4. The method of claim 1, wherein the magnetic force acoustic coupling gap is a closed region. 5 The film thickness T on the surface of the measured material is as follows: wherein Δt is the round-trip propagation time of the ultrasonic wave from the probe to the reception of the echo; and v is the propagation speed of the ultrasonic wave in the measured material.

5. The method of claim 1, wherein the method is a high-precision measurement method of a gap in a closed area inside a magnetic-force-acoustic coupling, characterized in that, The step of calculating the micro-gap between the film and the surface of the measured material comprises the following steps: 4.1) Calculate the distance measurement error δ D i.e.: where δ D is the distance measurement error; δ U is the pressure sensor (1) output signal measurement error. 4.2) Calculation of the ultrasonic thickness measurement error δ T i.e.: where δ T is the thickness measurement error; δ v is the sound speed error; and δ Δt is the time measurement error. 4.3) Calculate the thickness measurement error δ due to sensor position bias position i.e.: δ position = S - Δx (6) wherein S is the ratio of the film thickness T on the surface of the measured material to the position; x is the scanning position coordinate along the surface of the component; and Δx is the position deviation value, namely the position difference of the sensor module deviating from the preset path; 4.4) calculating the total measurement error, namely: Wherein, δ total is the total error. δ D is the error of magnetic ranging. δ T is the error of ultrasonic thickness measurement. δ position is the error caused by position deviation; 4.5) calculating the preliminary micro-gap X between the film and the surface of the measured material, namely: X=D-T (9) 4.6) correcting the preliminary micro-gap X to obtain the micro-gap between the film and the surface of the measured material, namely: X' = X - δ position (10) 4.7) judging the uncertainty X of the micro-gap X' ′ ±δ total whether the engineering requirement is satisfied, and if so, outputting the micro-gap X' 6. The method of claim 5, wherein the magnetic force acoustic coupling gap is a closed region. If the uncertainty X of the micro-gap X' does not meet the engineering requirements, the following steps are performed: ′ ±δ total the following steps are performed: S1) repeatedly measuring the micro-gap X' to exclude incidental noise or single-point measurement abnormality; if the repeatedly measured micro-gap X' still does not meet the engineering requirements, then step S2) is entered; S2) will δ total Disassembled into δ D δ T With δ position The process consists of three parts: by comparing calibration data, it is determined whether the error is due to the accumulation of errors in the measurement system itself. If so, the error is reduced by recalibrating and correcting, and the micro-gap X' is recalculated. If the recalculated micro-gap X' still does not meet the engineering requirements, then proceed to step S3. S3) determining that the workpiece film quality has defects, automatically generating a detection report, and recording the workpiece model, batch number, and defect position in the database.

7. A method for high-precision measurement of the gap and micro-displacement inside a closed area with "magnetic-force-acoustic" coupling, characterized in that, The method comprises the following steps: 1) Install a sensor module on each joint of the multi-joint rotary wheel (7); 2) System power-on self-test, initialize mechanical arm zero point and sensor status; 3) Operator inputs workpiece model, scanning area, error threshold on host computer; 4) Automatic scanning mechanical arm is in place, the mechanical arm moves to the starting point according to the preset path; complete workpiece coordinate system correction by laser or visual positioning; 5) Start the sensor, power on the magnetic probe, pressure sensor (1), ultrasonic probe and complete self-test and zero point calibration. 6) Control the automatic scanning mechanical arm to move, so that the sensor module is close to the surface of the measured material, thereby detecting the magnetic force between the magnetic force detection probe (3) and the measured material, and calculating the vertical distance D between the magnetic force detection probe (3) and the surface of the measured material, that is: In the formula, U is the voltage or current signal output by the pressure sensor (1); S is the sensitivity coefficient of the pressure sensor (1); M is the magnetic moment strength of the magnet; μ is the relative magnetic permeability of the measured material; n is the attenuation index; k is the proportional coefficient; 7) Use the ultrasonic detection probe to synchronously measure the film thickness T on the surface of the measured material, that is: Where Δt is the round-trip propagation time of the ultrasonic wave from the probe to the received echo; v is the propagation speed of the ultrasonic wave in the measured material. 8) Use the high-speed bus to send the vertical distance between the magnetic force detection probe (3) and the surface of the measured material and the film thickness T on the surface of the measured material to the controller, with a time stamp to ensure synchronization; 9) Real-time calculation of the micro-gap X between the film and the surface of the measured material = D-T; 10) Calculate compensation term δ from thickness gradient s = dT / dx and probe displacement Δx position and correct micro-gap X to get accurate gap value X' = X - δ position .

8. The method of claim 7, wherein the magnetic force acoustic coupling gap is a closed region.

8. The method of claim 7, wherein the magnetic force acoustic coupling gap is a closed region. After obtaining the accurate gap value, the following steps are also performed: 11) Generate micro-gap distribution data, map the accurate gap value X' to the workpiece coordinates in real time to generate a heat map or contour grid; 12) Data storage and analysis, measurement data, equipment ID and batch number are written into the database; background statistics of abnormal points, calculation of qualified rate; 13) Automatically generate a detection report; 14) After the measurement is completed, the system issues a "measurement completed" signal for subsequent process calling. 15) The mechanical arm returns to the original position, and the mechanical arm executes the zero return or standby posture; turn off the probe power and recover the safety shield. 16) Log archiving, if there is no exception, the system enters standby; if a fault code is detected, automatically prompt the operation and maintenance.

9. A high-precision measurement method for the internal gap and minute displacement of a closed region using "magnetic-force-acoustic" coupling as described in claim 7, characterized in that, When installing a sensor module on each joint of the multi-joint rotary wheel (7), the following constraints are followed: Constraint 1: The structure of the sensor module installed on each joint is the same as or different from the structure of the sensor module installed on other joints; Constraint 2: The total number of pressure sensors (1) installed on the multi-joint rotary wheel (7) is at least 1, the total number of magnetic force detection probes (3) is at least 1, and the total number of ultrasonic detection probes (2) is at least 1; Constraint 3: At least one pressure sensor (1) is connected with a magnetic force detection probe (3) or an ultrasonic detection probe (2); Constraint 4: The structure of the sensor module is any of the following: Structure 1: includes pressure sensor (1), magnetic force detection probe (3), and ultrasonic detection probe (2) arranged from top to bottom; wherein the pressure sensor (1) is directly connected with the magnetic force sensor, and the ultrasonic detection probe (2) is placed below the magnetic force detection probe (3); Structure 2: comprising pressure sensor (1), magnetic force detection probe (3), ultrasonic detection probe (2) arranged in sequence from top to bottom, and ultrasonic detection probe (2) arranged in parallel with magnetic force detection probe (3); wherein pressure sensor (1) is connected with magnetic force detection probe (3); Structure 3: comprising pressure sensor (1), nested detection probe arranged in sequence from top to bottom; the nested detection probe comprises ultrasonic detection probe (2), and annular magnetic force detection probe (3) surrounding the outside of ultrasonic detection probe (2); wherein pressure sensor (1) is connected with ultrasonic detection probe (2); Structure 4: comprising pressure sensor (1) and ultrasonic detection probe (2) connected with each other, and magnetic force detection probe (3) connected with ultrasonic detection probe (2) or arranged independently from ultrasonic detection probe (2).

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