Ultrasonic sealing detection method and system based on flexible array pressure sensing

Abstract

The invention discloses an ultrasonic sealing detection method and system based on flexible array pressure sensing, and belongs to the technical field of packaging machinery detection. According to the method, a flexible pressure sensing array is integrated on a working surface of a sealing pressing mechanism, so that multi-point distributed real-time detection on clamping pressure of a sealing surface is realized, and friction loss and mechanism error influence in a force transmission path are reduced from a measurement link. The core innovation lies in that a real-time coupling feedback mechanism between pressure distribution characteristics and ultrasonic driving parameters is established, the ultrasonic amplitude, the action time and the partition power are dynamically adjusted according to the pressure mean value, the standard deviation and the gravity center offset, and closed-loop control of pressure distribution sensing, ultrasonic energy adjustment and sealing quality optimization is achieved. The technical problems that existing sealing pressure detection depends on a far-end single-point sensor, so that measurement is inaccurate, and pressure distribution cannot be reflected are solved, and the sealing quality has robustness on working condition fluctuation.

Description

Technical Field

[0001] This application relates to the field of packaging machinery testing technology, and in particular to an ultrasonic sealing testing method and system based on flexible array pressure sensing. Background Technology

[0002] Ultrasonic sealing technology, as an advanced sealing method in the woven bag packaging field, achieves the welding of plastic films through frictional heat generated by high-frequency vibration. In industrial applications, sealing quality directly affects product sealing performance, appearance consistency, and the reliability of subsequent transportation and storage. Currently, intelligent woven bag sealing equipment widely uses various sensors to monitor the sealing process, among which pressure detection, as a core means of assessing the sealing clamping state, plays an irreplaceable role in ensuring sealing quality. Existing pressure detection schemes for sealing equipment mainly adopt the following technical approaches: First, a force sensor is installed at the end of the cylinder piston rod to indirectly calculate the sealing pressure by measuring the output force of the push rod; second, strain gauges are arranged at key nodes of the linkage mechanism to use material deformation to infer the force; third, a pressure sensor inside the cylinder is used to measure the air pressure, and then the theoretical output force is calculated based on the effective area of ​​the cylinder.

[0003] However, existing sealing pressure detection technology has the following defects: (1) The measurement position is far from the sealing surface. The sensor is usually installed at the end of the cylinder or on the linkage mechanism. There is a long force transmission path from the actual sealing surface. In this path, the friction of the guide mechanism, the resistance of the sealing ring, the clearance of the linkage hinge and the elastic deformation of the frame will consume or change the force transmission characteristics, resulting in a systematic deviation between the value measured by the sensor and the actual pressure of the sealing surface; (2) Single-point measurement cannot characterize the pressure distribution. The sealing surface of the woven bag usually has a certain width. In the actual sealing process, due to the parallelism error of the sealing surface, the uneven thickness of the woven bag and the contents of the bag, the pressure distribution will be affected. Due to factors such as material distribution differences, the pressure along the sealing width direction is often unevenly distributed. A single sensor can only obtain the force information of a certain equivalent point and cannot identify local pressure insufficiency or overload. (3) Assembly tolerance affects measurement consistency. The mechanical connection between the sensor and the mechanism involves multiple mating surfaces. Differences in thread preload, deviations in gasket thickness, and deviations in installation angle will all change the proportional relationship of force transmission. (4) Dynamic response is constrained by the inertia of the mechanism. The sealing action is usually completed within hundreds of milliseconds to several seconds. During this period, the pressure goes through stages such as rapid establishment, pressure holding and release. Existing remote measurement schemes often cannot accurately capture transient pressure changes.

[0004] In summary, existing technologies suffer from the technical problem of relying on remote single-point sensors for sealing pressure detection, leading to inaccurate measurements and an inability to reflect the actual clamping pressure distribution on the sealing surface. Summary of the Invention

[0005] This invention provides an ultrasonic sealing detection method and system based on flexible array pressure sensing, which can realize multi-point distributed real-time detection of the clamping pressure of the sealing surface, and achieve adaptive optimization of sealing quality through real-time coupling feedback of pressure distribution characteristics and ultrasonic driving parameters. It solves the technical problems in the prior art that the sealing pressure detection relies on a remote single-point sensor, resulting in inaccurate measurement and inability to reflect the actual clamping pressure distribution of the sealing surface.

[0006] In a first aspect, the present invention provides an ultrasonic sealing detection method based on a flexible array pressure sensor. This method acquires pressure signals from multiple measuring units along the width direction of the sealing surface using a flexible pressure sensor array attached to the working surface of a sealing and pressing mechanism. The flexible pressure sensor array includes multiple pressure-sensitive units based on a high-temperature resistant flexible film. The pressure signals from the multiple measuring units are conditioned, including constant current source excitation, amplification, and filtering, converting the resistance change caused by pressure into a standard voltage signal. The conditioned signal undergoes analog-to-digital conversion and pressure distribution analysis to calculate spatial characteristic parameters of the pressure distribution, including the pressure mean, pressure standard deviation, and pressure centroid position. Based on the corresponding coupling control relationship between the spatial characteristic parameters and ultrasonic drive parameters, the output parameters of the ultrasonic drive module are adjusted in real time. The ultrasonic drive parameters include ultrasonic amplitude, ultrasonic action time, and zoned power, forming a closed-loop control of pressure distribution sensing and ultrasonic energy regulation. The sealing quality is determined based on the spatial characteristic parameters, and a sealing status evaluation result is output. As described above, this invention reduces errors caused by friction, gaps, and elastic deformation of force transmission mechanisms such as cylinders and connecting rods by directly attaching a flexible pressure sensor array to the working surface of the sealing and pressing mechanism. The measurement results truly reflect the actual stress state of the sealing surface. By replacing single-point equivalent measurement with multi-point array measurement, pressure distribution information along the sealing width direction can be obtained, providing data support for the refined evaluation of sealing quality. By establishing a real-time coupling feedback mechanism between the spatial characteristic parameters of pressure distribution and the ultrasonic drive parameters, the system can dynamically optimize process parameters according to the actual state during the sealing process of each bag, achieving robustness of sealing quality to fluctuations in operating conditions.

[0007] Preferably, the real-time adjustment of the output parameters of the ultrasonic drive module based on the corresponding coupling control relationship between the spatial characteristic parameters and the ultrasonic drive parameters includes: adjusting the ultrasonic amplitude using a proportional-integral control relationship according to the deviation between the average pressure value and the preset target value, and simultaneously outputting pressure increase / depression commands to the clamping actuator; increasing the ultrasonic amplitude and outputting a pressure increase command when the average pressure value is lower than the target value, and decreasing the ultrasonic amplitude and outputting a depression command when the average pressure value is higher than the target value; adjusting the ultrasonic action time using a piecewise linear relationship according to the ratio of the pressure standard deviation to the average pressure value, and extending the ultrasonic action time to compensate for the welding efficiency of the pressure uneven area when the ratio exceeds a first threshold; and adjusting the partition power using a linear mapping relationship according to the offset of the pressure center position relative to the sealing centerline, increasing the power output to the low-pressure side area and decreasing the power output to the high-pressure side area. As described above, this invention establishes a multi-dimensional coupling relationship between the average pressure and ultrasonic amplitude, pressure uniformity and ultrasonic action time, and pressure center of gravity shift and zone power, thereby achieving targeted compensation for different types of pressure anomalies. This enables the system to have adaptive optimization capabilities, cope with complex working conditions that cannot be solved by a single technical means, and produce an efficiency-enhancing effect.

[0008] Preferably, the ultrasonic amplitude is adjusted using a proportional-integral control relationship, specifically, the ultrasonic amplitude adjustment amount ΔA and the mean pressure deviation ΔP satisfy the following relationship: The proportionality coefficient K p The value ranges from 0.5 to 2.0 μm / MPa, and the integral coefficient K i The value range is 0.1 to 0.5 μm / (MPa·s). As described above, this invention, by employing a proportional-integral control relationship, can both rapidly respond to pressure deviations and eliminate steady-state errors, giving the ultrasonic amplitude adjustment excellent dynamic performance and steady-state accuracy. The parameter range is suitable for general working conditions of woven bag sealing.

[0009] Preferably, the step of adjusting the ultrasonic treatment time using a piecewise linear relationship is specifically defined as follows: when the pressure standard deviation σ and the pressure mean P... avg When the ratio is less than 0.05, the duration of ultrasound treatment Δt is zero; when the ratio is between 0.05 and 0.15, Δt = k·(σ / P) avg - 0.05), the coefficient k ranges from 50 to 200 ms; when the ratio exceeds 0.15, an alarm is triggered and the sealing action is paused. As described above, this invention, by setting a piecewise linear relationship and threshold judgment, does not intervene when the pressure distribution is uniform, performs moderate compensation when the pressure distribution is slightly uneven, and triggers protection when the pressure distribution is severely uneven. This achieves graded processing of pressure anomalies of different degrees, ensuring sealing quality while avoiding the side effects of over-compensation.

[0010] Preferably, the flexible pressure sensing array adopts the piezoresistive sensing principle, and the pressure sensing unit is composed of conductive filler dispersed in an elastomer substrate. The conductive filler is carbon nanotubes or metal particles, and the high-temperature resistant flexible film is a polyimide film or a polyetheretherketone film. In summary, by selecting the piezoresistive sensing principle and high-temperature resistant materials, this invention enables the flexible pressure sensing array to have advantages such as simple signal conditioning circuitry, large output signal amplitude, and good high-temperature resistance, allowing it to operate stably for a long time in the harsh environment of ultrasonic sealing.

[0011] Preferably, a heat-insulating gasket is provided between the flexible pressure sensing array and the sealing surface. The heat-insulating gasket is made of aerogel material with a thickness of 0.2 mm to 0.5 mm and a thermal conductivity not exceeding 0.02 W / (m·K). A metal heat dissipation layer is provided on the back of the flexible pressure sensing array. In summary, this invention, by providing an aerogel heat-insulating gasket and a metal heat dissipation layer, establishes a thermal protection system that can control the operating temperature of the sensing array within a safe range, solving the problems of limited sensor installation location and inability to directly measure the pressure of the sealing surface in existing technologies.

[0012] Preferably, the filtering process employs an adaptive filtering strategy synchronized with the ultrasonic drive frequency, including obtaining the current ultrasonic operating frequency from the ultrasonic drive module and dynamically setting the cutoff frequency of the low-pass filter according to the current ultrasonic operating frequency, wherein the cutoff frequency f c Satisfy: f p,max < f c < f _us / 10, where f us f is the current ultrasonic operating frequency. p,max This represents the upper limit of the effective frequency range of the pressure signal. Fluctuations in the ultrasonic operating frequency are tracked, and the filtering parameters are adjusted in real time to maintain consistent filtering performance. As described above, this invention employs an adaptive filtering strategy synchronized with the ultrasonic drive frequency, which offers greater adaptability compared to fixed-parameter filtering. It is particularly suitable for applications where the ultrasonic frequency has a certain fluctuation range, enabling pressure detection to achieve a good signal-to-noise ratio under various operating conditions.

[0013] Preferably, the pressure distribution analysis further includes pressure distribution pattern recognition. Specifically, this involves establishing a pressure distribution feature template library containing defect types such as sealing head tilt, bag opening wrinkles, material clamping, and leak sealing. The spatial feature parameters calculated in real time are matched with the feature template library to identify the defect type corresponding to the current sealing state. Manually confirmed defect samples are recorded, and the feature template library is updated using an incremental learning algorithm. In summary, by establishing a pressure distribution pattern library and introducing a self-learning mechanism, this invention enables the pressure detection module to not only provide raw data but also output defect diagnosis results, providing a foundation for intelligent quality control and continuously updating pattern features to adapt to the specific operating conditions of production lines.

[0014] Preferably, the pressure distribution analysis further includes zero-point calibration and temperature compensation. Specifically, the output of each measurement unit is collected under no-load conditions before each sealing operation as a zero-point reference. The operating temperature is obtained through the temperature sensing unit built into the flexible pressure sensor array. Based on the operating temperature, a corresponding piecewise linear correction coefficient is selected to compensate for the pressure measurement value. In summary, by implementing zero-point calibration and temperature compensation, this invention eliminates offset errors caused by temperature drift and long-term creep, ensuring the accuracy and consistency of pressure measurements.

[0015] Secondly, this invention provides an ultrasonic sealing detection system based on a flexible array pressure sensor, comprising a flexible pressure sensor array, a heat insulation pad, a signal conditioning circuit, a data acquisition module, and a main control unit. The flexible pressure sensor array is attached to the working surface of the sealing and pressing mechanism and includes multiple pressure-sensitive units arranged along the sealing width direction using a high-temperature resistant flexible film as a substrate, used to convert the mechanical pressure at various points on the sealing surface into resistance change signals. The heat insulation pad is disposed between the flexible pressure sensor array and the sealing surface to prevent heat generated during the sealing process from being conducted to the sensing units. The signal conditioning circuit is connected to the flexible pressure sensor array and includes a constant current source excitation module, an instrumentation amplifier, and a low-pass filter, used to convert the resistance changes of each pressure-sensitive unit into standard voltage signals. The data acquisition module includes a multiplexer and an analog-to-digital converter, used to scan and acquire data from the multiple measurement units of the flexible pressure sensor array and perform digital conversion. The main control unit is connected to the data acquisition module and the ultrasonic drive module. It is used to execute the pressure distribution analysis algorithm to calculate the pressure mean, pressure standard deviation and pressure center of gravity position, and output adjustment commands for amplitude, action time and zone power to the ultrasonic drive module based on the coupling control relationship, so as to realize closed-loop control of pressure distribution sensing and ultrasonic energy regulation.

[0016] Thirdly, the present invention provides an electronic device, the device including a processor and a memory, the memory being used to store computer-executable instructions, and when the electronic device is running, the processor executing the computer-executable instructions stored in the memory to cause the electronic device to perform the ultrasonic sealing detection method based on flexible array pressure sensing as described in the first aspect.

[0017] Fourthly, the present invention provides a storage medium for storing computer-executable instructions, which, when executed by a processor, are used to implement the ultrasonic sealing detection method based on flexible array pressure sensing as described in the first aspect.

[0018] The beneficial effects of the present invention, as described above, include:

[0019] (1) Improved measurement accuracy: Due to the elimination of the friction and deformation effects of the force transmission mechanism, the systematic error of pressure measurement is reduced from 10% to 20% in the prior art to less than 3%, and the repeatability error is reduced from more than 5% to less than 2%.

[0020] (2) Breakthrough in spatial resolution: Multi-point array measurement can identify pressure non-uniformity on a scale of 5mm to 10mm along the width of the seal, which is a certain improvement over the existing single-point measurement.

[0021] (3) The real-time coupling feedback mechanism of pressure distribution characteristics and ultrasonic driving parameters improves the stability of sealing quality by 2 to 3 times and reduces the incidence of pressure-related defects such as false sealing and over-sealing by more than 60%.

[0022] (4) Improved dynamic response capability, with a full array scanning cycle of no more than 2ms and a total delay from pressure deviation detection to effective ultrasound parameter adjustment of no more than 10ms;

[0023] The core of this application's inventiveness lies in establishing a multi-dimensional real-time coupling feedback mechanism between pressure distribution spatial characteristic parameters and ultrasonic driving parameters. Through negative feedback adjustment of pressure mean and ultrasonic amplitude, positive compensation of pressure uniformity and ultrasonic action time, and linear mapping of pressure center of gravity shift and zone power, a closed-loop control of pressure distribution perception, ultrasonic energy adjustment, and sealing quality optimization is achieved, enabling the system to have adaptive optimization capabilities and cope with complex working conditions that cannot be solved by a single technical means. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the ultrasonic sealing detection method based on flexible array pressure sensing provided by the present invention.

[0025] Figure 2 This is a schematic diagram of the ultrasonic sealing detection system based on flexible array pressure sensing provided by the present invention.

[0026] Figure 3 This is a schematic diagram illustrating the coupling relationship between the spatial characteristic parameters of pressure distribution and the ultrasonic driving parameters provided by the present invention.

[0027] Figure 4 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly described below with reference to the accompanying drawings. It should be noted that, unless otherwise specified, the embodiments and technical features described in this application can be combined with each other.

[0029] Terminology Explanation

[0030] Flexible pressure sensor array: refers to an array-type sensor formed by integrating multiple regularly arranged pressure-sensitive units as a substrate. In this application, the flexible pressure sensor array adopts the piezoresistive sensing principle, which can be attached to the working surface of the sealing and pressing mechanism to realize distributed measurement of multi-point pressure on the sealing surface. Its flexible characteristics enable it to adapt to the shape and deformation of the sealing surface.

[0031] Pressure-sensitive element: refers to the basic sensing element in a flexible pressure sensing array, which is composed of conductive filler dispersed in an elastomer substrate. When an external force is applied, the elastomer deforms under pressure, the spacing between the conductive particles changes, resulting in a change in the element resistance, thereby realizing the conversion of pressure into an electrical signal.

[0032] Spatial characteristic parameters: These are statistical quantities extracted from multi-point pressure data that characterize the spatial distribution of pressure. In this application, spatial characteristic parameters include the pressure mean, pressure standard deviation, and pressure centroid location, which respectively reflect the overall clamping degree, pressure uniformity, and the offset trend of pressure distribution.

[0033] Average pressure: refers to the arithmetic mean of the pressure values ​​of all measuring units in the flexible pressure sensor array, used to characterize the overall clamping degree of the sealing surface.

[0034] Pressure standard deviation: refers to the degree of dispersion of the pressure value of each measurement unit relative to the pressure mean. It is used to characterize the uniformity of pressure distribution. The larger the standard deviation, the more uneven the pressure distribution.

[0035] Pressure center of gravity position: refers to the coordinates of the pressure distribution center obtained by weighted calculation based on the pressure values ​​of each measurement unit, used to characterize the offset trend of the pressure distribution relative to the centerline of the seal.

[0036] Coupled control refers to the real-time correlation control relationship established between pressure distribution detection results and ultrasonic drive parameters. In this application, coupled control includes three dimensions: negative feedback adjustment of pressure mean and ultrasonic amplitude, positive compensation of pressure uniformity and ultrasonic action time, and linear mapping of pressure center of gravity shift and zone power.

[0037] Zoned power: refers to the ultrasonic power applied to different areas along the width of the seal when using a zoned transducer design. By adjusting the zoned power, energy distribution compensation along the width of the seal can be achieved.

[0038] Adaptive filtering strategy: refers to a filtering method in which the filter parameters can be dynamically adjusted according to the actual working conditions. In this application, the adaptive filtering strategy dynamically sets the cutoff frequency of the low-pass filter according to the actual operating frequency of the ultrasonic drive module, so that the filtering effect can adapt to the fluctuations of the ultrasonic frequency.

[0039] Thermal insulation pad: refers to a thin layer of thermal insulation material disposed between the flexible pressure sensing array and the sealing surface. In this application, the thermal insulation pad is made of aerogel material, which utilizes its extremely low thermal conductivity to block the heat generated during the sealing process from being conducted to the sensing unit.

[0040] Detailed technical solution

[0041] This invention provides an ultrasonic sealing detection method based on a flexible array pressure sensor. For example... Figure 1 As shown, the method includes the following steps:

[0042] Step 101: Acquire multi-point pressure signals on the sealing surface using a flexible pressure sensor array.

[0043] A flexible pressure sensor array is attached to the working surface of the sealing and pressing mechanism, with multiple measuring units arranged along the sealing width direction. During the sealing action, the opening of the woven bag is clamped between the ultrasonic sealing head and the lower pressure plate. The flexible pressure sensor array senses the clamping pressure at each point on the sealing surface and converts the mechanical pressure into resistance changes of each pressure-sensitive unit.

[0044] The flexible pressure sensing array employs a piezoresistive structure based on a polyimide or polyetheretherketone (PEEK) film substrate, with the substrate thickness controlled within the range of 0.3 mm to 0.5 mm. The pressure-sensitive units are composed of conductive fillers such as carbon nanotubes or metal particles dispersed within the elastomer substrate, arranged regularly at intervals of 5 mm to 10 mm along the width of the seal, typically configured with 8 to 32 units. The effective pressure-sensing area of ​​each unit is approximately 10 mm². 2 Up to 20mm 2 The range covers 0 to 2 MPa.

[0045] To withstand the high-temperature environment of ultrasonic sealing, an aerogel thermal insulation pad with a thickness of 0.2 mm to 0.5 mm and a thermal conductivity not exceeding 0.02 W / (m·K) is placed between the flexible pressure sensing array and the sealing surface. Simultaneously, a metal heat dissipation layer is placed on the back of the array, utilizing the heat capacity of the lower pressure plate to accelerate heat dissipation and control the operating temperature of the sensing array below 150℃.

[0046] Step 102: Perform signal conditioning on the multi-point pressure signals.

[0047] The signal conditioning circuit processes the resistance change signal output by the flexible pressure sensor array and converts it into a standard voltage signal suitable for analog-to-digital conversion.

[0048] Signal conditioning first employs a constant current source excitation method, applying a stable bias current, typically 0.5mA to 2mA, to each pressure-sensitive unit, and then measuring the voltage change across its terminals. This constant current source excitation directly converts changes in the sensing unit's resistance into voltage changes, simplifying subsequent signal processing.

[0049] The amplifier circuit adopts an instrumentation amplifier topology with an adjustable gain range of 50 to 200 times, a common-mode rejection ratio of not less than 80dB, and an equivalent input noise of not more than 10μV (RMS). The instrumentation amplifier amplifies the millivolt-level signal from the sensing unit to the input range of the analog-to-digital converter.

[0050] The filtering circuit employs an adaptive filtering strategy synchronized with the ultrasonic drive frequency. The current ultrasonic operating frequency is obtained from the ultrasonic drive module, and the cutoff frequency of the low-pass filter is dynamically set based on this frequency, ensuring that the cutoff frequency is lower than the ultrasonic operating frequency but higher than the upper limit of the effective pressure signal frequency range. Since the ultrasonic sealing frequency is typically between 20kHz and 40kHz, while the effective sealing pressure signal is concentrated in the DC to several hundred hertz range, the filter cutoff frequency is set to 500Hz to 1kHz. The filter uses an active second-order Butterworth structure, providing attenuation of ultrasonic vibration noise by more than 40dB.

[0051] Step 103: Perform analog-to-digital conversion and pressure distribution analysis on the conditioned signal.

[0052] The analog-to-digital conversion circuit uses a successive approximation converter with a resolution of 12 to 16 bits. The multiplexer reads the signal of each measurement unit one by one in a row and column scanning manner, with a full array scan period of no more than 2ms and an effective sampling rate of no less than 500Hz per channel.

[0053] Before pressure distribution analysis, zero-point calibration and temperature compensation are performed first. The outputs of each measurement unit are collected under no-load conditions before each sealing operation as a zero-point reference to eliminate offset errors caused by temperature drift and long-term creep. The operating temperature is obtained through the temperature sensing unit built into the flexible pressure sensor array, and a corresponding piecewise linear correction coefficient is selected based on the operating temperature to perform temperature compensation on the pressure measurements.

[0054] Analytical calculation of pressure distribution for three types of spatial characteristic parameters: mean pressure P avg The pressure is the arithmetic mean of the pressure values ​​of all measuring units, reflecting the overall clamping degree; the pressure standard deviation σ is the standard deviation of the pressure values ​​of each unit, reflecting the pressure uniformity; the pressure center of gravity position... The pressure distribution shifts by multiplying the pressure value of each unit by the weighted average of its position coordinates and then dividing by the total pressure.

[0055] Pressure distribution analysis also includes pattern recognition functionality. A pressure distribution feature template library is established, encompassing defects such as sealing head tilt, bag opening wrinkles, material clamping, and incomplete sealing. Real-time calculated spatial feature parameters are matched against this template library to identify the defect type corresponding to the current sealing state. The system records manually confirmed defect samples and uses an incremental learning algorithm to update the pattern templates, gradually adapting to the specific operating conditions of the production line.

[0056] Step 104: Adjust ultrasonic drive parameters in real time based on coupling relationship

[0057] like Figure 3 As shown, this step is the core innovation of the present invention: based on the corresponding coupling control relationship between spatial characteristic parameters and ultrasonic drive parameters, the output parameters of the ultrasonic drive module are adjusted in real time to form a closed-loop control of pressure distribution sensing and ultrasonic energy regulation.

[0058] Coupling adjustment of pressure mean and ultrasonic amplitude: based on pressure mean P avg The deviation from the preset target value P0 is ΔP = P avg - P0, using a proportional-integral control relationship to adjust the ultrasonic amplitude. Ultrasonic amplitude adjustment amount. The proportionality coefficient K p The value ranges from 0.5 to 2.0 μm / MPa, and the integral coefficient K i The value range is 0.1 to 0.5 μm / (MPa·s). When the average pressure is lower than the target value, it indicates that the clamping force is insufficient. The system increases the ultrasonic amplitude and limits the amplitude to avoid film misalignment, while feeding back to the cylinder pressure control circuit to increase the clamping force. When the average pressure is higher than the target value, the ultrasonic amplitude is appropriately reduced to avoid over-sealing.

[0059] Coupling adjustment of pressure uniformity and ultrasonic treatment time: based on pressure standard deviation σ and pressure mean P avg The ratio of the two values ​​is used to adjust the ultrasound treatment time using a piecewise linear relationship; that is... When σ / P avg When σ / P is less than 0.05, the pressure distribution is uniform, and the extension of ultrasonic treatment time Δt is zero; when σ / P avg When the value is between 0.05 and 0.15, Δt = k·(σ / P) avg -0.05), the coefficient k ranges from 50 to 200 ms, allowing the low-pressure region to receive more energy input; when σ / P avg When the pressure exceeds 15%, the pressure distribution becomes severely uneven, triggering an alarm and suspending the sealing process.

[0060] Coupling adjustment of pressure center of gravity offset and zone power: based on the position of pressure center of gravity. The partition power is adjusted using a linear mapping relationship relative to the offset Δx of the sealing centerline. The sealing centerline is taken as the origin, with the rightward direction being positive; the power coefficient for the left partition is (1+α), and the power coefficient for the right partition is (1-α), where α = K x ·Δx, coefficient K xThe value ranges from 0.02 to 0.1 (1 / mm). Energy distribution compensation along the sealing width direction is achieved through zoned power adjustment. ΔA, Δt, and α are all amplitude-limited to ensure that the ultrasonic amplitude, action time, and power of each zone are always within the allowable range of the equipment.

[0061] Step 105: Determine the sealing quality and output the evaluation results.

[0062] Sealing quality is assessed based on spatial characteristic parameters and their changing trends. The assessment includes: whether the average pressure is within the allowable range, whether the pressure distribution uniformity meets requirements, and whether specific defect patterns are identified. The sealing status evaluation results are output, including qualified, requiring compensation, and alarm status, providing quality traceability data for subsequent processes.

[0063] The core innovation of this invention lies in the real-time coupling feedback mechanism between the spatial characteristic parameters of pressure distribution and the ultrasonic driving parameters.

[0064] This invention establishes a real-time coupled feedback mechanism between pressure distribution detection results and ultrasonic driving parameters, involving the interaction between three sets of parameters: pressure mean and ultrasonic amplitude, pressure standard deviation and ultrasonic action time, and pressure center of gravity shift and zone power. These three sets of parameters work together to form a multi-dimensional closed-loop control system, realizing a feedback loop of pressure distribution sensing—ultrasonic energy adjustment—sealing quality optimization.

[0065] II. Specific Mechanisms of Parameter Coupling

[0066] Negative feedback coupling relationship between mean pressure and ultrasonic amplitude

[0067] Mean pressure P avg The ultrasonic amplitude A, reflecting the overall clamping tightness of the sealing surface, determines the intensity of the sealing energy. A negative feedback coupling relationship exists between the two: when the clamping force is insufficient (low average pressure), maintaining the original ultrasonic amplitude will result in an excessively large gap between the sealing surfaces, leading to incomplete welding; conversely, when the clamping force is excessive (high average pressure), an insufficient ultrasonic amplitude will reduce welding efficiency. Therefore, it is necessary to dynamically adjust the ultrasonic amplitude based on the average pressure to maintain coordination between the two.

[0068] Wherein, the proportionality coefficient K p The value ranges from 0.5 to 2.0 μm / MPa, with a preferred value of 1.0 μm / MPa; the integral coefficient K i The value ranges from 0.1 to 0.5 μm / (MPa·s), with a preferred value of 0.2 μm / (MPa·s). The target average pressure value P0 is set according to the material and thickness of the woven bag, and generally ranges from 0.3 to 1.0 MPa.

[0069] A proportional-integral control law is employed, with the proportional term providing rapid response and the integral term eliminating steady-state error. The control cycle is synchronized with the pressure sampling cycle, typically 2 ms.

[0070] Positive compensatory coupling relationship between pressure uniformity and ultrasonic treatment time

[0071] Coupling Mechanism: The pressure standard deviation σ reflects the uniformity of pressure distribution along the sealing width direction, while the ultrasonic treatment time t determines the cumulative amount of sealing energy. When the pressure distribution is uneven, the welding efficiency in the low-pressure area is lower than that in the high-pressure area, which will lead to localized incomplete sealing if no compensation is made. By extending the ultrasonic treatment time, the low-pressure area receives sufficient energy input, compensating for the decrease in welding efficiency caused by insufficient clamping.

[0072] Coupling condition: the ratio of the pressure standard deviation to the pressure mean, σ / P avg As an indicator of uniformity, a ratio less than 0.05 indicates uniform pressure distribution, requiring no compensation; a ratio between 0.05 and 0.15 triggers a compensation mechanism; and a ratio exceeding 0.15 indicates severely uneven pressure distribution, necessitating shutdown for inspection.

[0073] Within the compensation range, the extension of the ultrasonic treatment time is directly proportional to the portion of the uniformity index exceeding the threshold, and the coefficient k determines the compensation intensity. By setting a reasonable value for k, a balance can be achieved between extending the treatment time (increasing energy input) and controlling overheating in the high-pressure region.

[0074] Linear mapping coupling relationship between pressure center of gravity offset and partition power

[0075] Coupling mechanism: Location of pressure center of gravity Reflecting the shift in pressure distribution, the zoned power determines the energy distribution along the seal width. When the pressure center of gravity deviates from the seal centerline, it indicates that one side is securely clamped while the other side is weakly clamped. By adjusting the zoned power, increasing the power output to the low-pressure side and decreasing the power output to the high-pressure side, spatial compensation of the energy distribution is achieved.

[0076] Specific parameter range: mapping coefficient K x The value ranges from 0.02 to 0.1 (1 / mm), with a preferred value of 0.05 (1 / mm). Power regulation coefficient α = K x ·Δx, where Δx is the offset of the pressure center of gravity relative to the centerline of the seal; a positive value indicates an offset to one side. After adjustment, the power on the low-pressure side is P0·(1+α), and the power on the high-pressure side is P0·(1-α), where P0 is the nominal power.

[0077] Matching method: Zoned power adjustment requires the ultrasonic drive module to support the zoned transducer design. In practical applications, the sealing width can be divided into 2 to 4 power control zones, and the power ratio of each zone can be allocated according to the pressure center offset.

[0078] This invention achieves the following effects through the coupling mechanism of the above three sets of parameters:

[0079] 1. Multi-dimensional anomaly coverage: Compared to using any single coupling relationship, the combination of three coupling relationships can handle more types of pressure anomalies. Pressure mean adjustment addresses overall clamping force deviation, application time adjustment addresses uniformity deviation, and zoned power adjustment addresses spatial distribution deviation; these three complement each other to form an anomaly response system. Individually, they can only handle a single type of anomaly; combined, they can simultaneously handle multiple complex anomalies, increasing anomaly coverage from approximately 60% to over 95%.

[0080] 2. Quality stability: Under the condition of woven bag thickness fluctuation of ±10%, the coefficient of variation of sealing tensile strength is about 8% when only the average pressure-amplitude coupling is used, about 7% when only the action time compensation is used, and about 9% when only the zone power adjustment is used. After using the combination of the three, the coefficient of variation is reduced to 3% to 5%, an improvement of about 50%, which reflects the efficiency enhancement effect.

[0081] 3. The multiplicative effect of defect rate reduction: Pressure mean adjustment can reduce the defect rate caused by clamping force deviation from 15% to 8%; action time compensation can reduce the defect rate caused by uniformity deviation from 12% to 6%; zoned power adjustment can reduce the defect rate caused by spatial distribution deviation from 10% to 5%. When the three mechanisms act independently, the total defect rate is approximately 19%. After combined action, due to the mutual compensation effect, the total defect rate is reduced to below 6%, a reduction far exceeding the expectation of simply adding the three together.

[0082] From a technical principle perspective, the reasons why individual technical features cannot achieve the combined effect are as follows:

[0083] Using pressure mean-amplitude coupling alone: ​​This mechanism can only adjust the overall energy output intensity and cannot cope with uneven pressure distribution. When there is a large pressure difference on both sides of the sealing surface, even if the overall energy is appropriate, the low-pressure side may still be incompletely sealed and the high-pressure side may still be over-sealed.

[0084] Using only the duration of action for compensation: This mechanism compensates for insufficient uniformity by extending the overall duration of action, but it cannot distinguish spatial differences in energy demand. Extending the duration can lead to excess energy in high-voltage areas, posing a risk of over-fusion.

[0085] Individual zone power regulation: This mechanism can achieve spatial energy distribution, but the adjustment range is limited by the power margin. When the overall clamping force deviation is large, simple power distribution cannot fundamentally solve the problem.

[0086] The combination of these three elements forms a hierarchical and complementary regulation system: pressure mean-amplitude coupling ensures energy matching at the total level, time-of-action compensation compensates for insufficient uniformity in the time dimension, and zoned power regulation achieves fine allocation in the spatial dimension. These three dimensions work together, and any deficiency in one dimension can be compensated for by the others, forming a redundant and reliable control architecture.

[0087] The specific implementation parameters are summarized as follows:

[0088] Parameter name Parameter range Preferred value Function Description <![CDATA[Proportionality coefficient K p > 0.5~2.0 μm / MPa 1.0 μm / MPa Controlling the response speed of amplitude to pressure deviation <![CDATA[Integration coefficient K i > 0.1~0.5 μm / (MPa·s) 0.2 μm / (MPa·s) Eliminating steady-state error in amplitude regulation Uniformity threshold 0.05 0.05 Time compensation will not be activated if the value is below this. Uniformity threshold 0.15 0.15 Exceeding this value will trigger an alarm and shutdown. Time compensation coefficient k 50~200 ms 100 ms The extent of the extension of the control action time <![CDATA[Power mapping coefficient K x > 0.02~0.1 (1 / mm) 0.05 (1 / mm) Control zone power adjustment sensitivity <![CDATA[Pressure mean target P0]]> 0.3~1.0 MPa 0.5 MPa Set according to material thickness Control cycle 1~5 ms 2 ms Update frequency of coupled feedback

[0089] Example 1

[0090] The specific application of this invention is illustrated by taking the ultrasonic sealing process of a 50kg woven bag as an example.

[0091] Application Scenario: A fertilizer packaging production line uses ultrasonic sealing equipment to seal PP woven bags. The sealing width is 150mm, and the sealing time for a single bag is approximately 1.5 seconds. During the production process, due to the ±8% tolerance fluctuation in the thickness of the woven bags and the uneven distribution of fertilizer particles inside the bags, the sealing qualification rate of the existing equipment is only 92%.

[0092] System configuration: A 16-unit flexible pressure sensor array is attached to the surface of the sealing pressure plate, with a unit spacing of 10mm, covering the sealing width. The sensor array uses a polyimide substrate and carbon nanotube conductive filler, and a 0.3mm thick aerogel thermal insulation pad is placed between the sensor array and the sealing surface. The ultrasonic drive module is configured with a 4-zone transducer design, operating at a frequency of 20kHz.

[0093] Execution process: After the sealing action is initiated, the cylinder drives the lower pressure plate downward, clamping the woven bag opening between the sealing head and the lower pressure plate. A flexible pressure sensor array collects pressure signals from 16 measuring points in real time, which are then processed by the signal conditioning circuit and sent to the main control unit.

[0094] The main control unit calculates the spatial characteristic parameters: the average pressure P of this sealing operation. avg = 0.42MPa, lower than the target value P0 = 0.5MPa, deviation ΔP = -0.08MPa; pressure standard deviation σ = 0.035MPa, σ / P avg = 0.083, exceeding the 0.05 threshold; the pressure center of gravity shifts 3mm to the left relative to the sealing centerline, Δx = -3mm, where Δx is the offset of the pressure center of gravity relative to the sealing centerline. It is stipulated that Δx>0 indicates a rightward shift (the right side is the high-pressure side and the left side is the low-pressure side), and Δx<0 indicates a leftward shift.

[0095] Adjusting ultrasonic parameters based on coupling relationship: Based on the pressure mean deviation, the ultrasonic amplitude adjustment ΔA = -1.0×(-0.08) - 0.2×∫(-0.08)dt = 0.08 + 0.016 = 0.096μm (assuming integration time 1s). The system increases the ultrasonic amplitude from the nominal value of 25μm to 25.1μm, and at the same time sends a pressurization command to the cylinder pressure control circuit.

[0096] Based on the pressure uniformity index, the extension of ultrasonic action time Δt = 100×(0.083 - 0.05) = 3.3ms is calculated. The system extends the ultrasonic action time from the nominal value of 800ms to 803.3ms.

[0097] Based on the pressure center offset, α = 0.05×(-3) = -0.15, the system adjusts the power of the left (Δx is the negative direction side) partition to P0×(1+α)=0.85P0 and the power of the right (Δx is the positive direction side) partition to P0×(1-α)=1.15P0, thereby increasing the power output of the right side (low pressure side).

[0098] After sealing is completed, the system determines that the sealing quality is qualified based on spatial characteristic parameters, and records the pressure curve and parameter adjustment process of this sealing for traceability analysis.

[0099] like Figure 2 As shown, the present invention also provides an ultrasonic sealing detection system based on a flexible array pressure sensor, the system comprising a flexible pressure sensor array 210, a heat insulation pad 220, a signal conditioning circuit 230, a data acquisition module 240, and a main control unit 250.

[0100] The flexible pressure sensor array 210 is attached to the working surface of the sealing and clamping mechanism, such as... Figure 3 As shown, the array includes a flexible substrate 211, pressure-sensitive units 212, electrode leads, and a temperature-sensing unit 214. The flexible substrate 211 is made of polyimide film or polyetheretherketone film, with a thickness of 0.3 mm to 0.5 mm and a temperature resistance rating of up to 250°C. The pressure-sensitive units 212 are composed of conductive fillers such as carbon nanotubes or metal particles dispersed in an elastomer substrate, arranged regularly at intervals of 5 mm to 10 mm along the width of the seal, with a quantity of 8 to 32 units. The electrode leads use a flexible copper foil-coated polyimide structure to connect each pressure-sensitive unit to a signal conditioning circuit. The temperature-sensing unit 214 is used to monitor the operating temperature of the sensing array, providing a basis for temperature compensation.

[0101] A heat-insulating pad 220 is disposed between the flexible pressure sensor array 210 and the sealing surface. It is made of aerogel material with a thickness of 0.2 mm to 0.5 mm and a thermal conductivity not exceeding 0.02 W / (m·K), and is used to prevent heat generated during the sealing process from being conducted to the sensing unit. A metal heat dissipation layer is also disposed on the back of the flexible pressure sensor array 210 to accelerate heat dissipation by utilizing the heat capacity of the lower pressure plate.

[0102] The signal conditioning circuit 230 includes a constant current source excitation module 231, an instrumentation amplifier 232, and a low-pass filter 233. The constant current source excitation module 231 applies a stable bias current of 0.5mA to 2mA to each pressure-sensitive unit. The instrumentation amplifier 232 provides an adjustable gain of 50 to 200 times and a common-mode rejection ratio of not less than 80dB. The low-pass filter 233 employs an active second-order Butterworth structure with a cutoff frequency of 500Hz to 1kHz, and can be dynamically adjusted according to the ultrasonic drive frequency.

[0103] The data acquisition module 240 includes a multiplexer 241 and an analog-to-digital converter 242. The multiplexer 241 selects each measurement unit one by one in a row-column scanning manner. The analog-to-digital converter 242 adopts a successive approximation structure with a resolution of 12 bits to 16 bits and a full array scan period of no more than 2 ms.

[0104] The main control unit 250 is connected to the data acquisition module 240 and the ultrasonic drive module 260, and is used to execute algorithms such as zero-point calibration, temperature compensation, pressure distribution analysis, pattern recognition, and coupled feedback control. The main control unit 250 calculates spatial characteristic parameters such as the pressure mean, pressure standard deviation, and pressure center of gravity position, and outputs adjustment commands for amplitude, action time, and zone power to the ultrasonic drive module 260 based on a preset coupling relationship, realizing closed-loop control of pressure distribution sensing and ultrasonic energy regulation. The main control unit 250 also includes a human-machine interface for parameter setting, status display, and alarm prompts.

[0105] like Figure 4 As shown, the present invention also provides an electronic device 700, which includes a processor 710, a memory 720 and a communication interface 730.

[0106] The processor 710 can be a general-purpose processor, including a central processing unit, a network processor, etc.; it can also be a digital signal processor, an application-specific integrated circuit, a field-programmable gate array, or other programmable logic devices. The processor 710 is used to execute computer-executable instructions stored in the memory 720 to implement the ultrasonic sealing detection method based on flexible array pressure sensing provided by the present invention.

[0107] The memory 720 can be volatile memory or non-volatile memory, or it can include both. Non-volatile memory can be read-only memory, programmable read-only memory, electrically erasable programmable read-only memory, or flash memory. Volatile memory can be random access memory. The memory 720 is used to store computer-executable instructions. When the electronic device 700 is running, the processor 710 communicates with the memory 720 via a bus, and the processor 710 executes the computer-executable instructions stored in the memory 720.

[0108] The communication interface 730 is used to interact with the flexible pressure sensing array, signal conditioning circuit, data acquisition module and ultrasonic drive module.

[0109] The present invention also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the ultrasonic sealing detection method based on flexible array pressure sensing provided by the present invention.

[0110] A computer-readable storage medium can be any available medium capable of storing computer programs, or a data storage device containing one or more available media. Available media can be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., optical discs), or semiconductor media (e.g., solid-state drives), etc.

[0111] Experimental verification

[0112] I. Experimental Objective

[0113] This experiment verifies the beneficial effects of the present invention through systematic experimental design and data collection.

[0114] II. Experimental Environment and Conditions

[0115] 2.1 Hardware Environment

[0116] The experimental platform was modified from the ultrasonic sealing equipment of a fertilizer packaging production line. The main hardware configuration is as follows:

[0117] The ultrasonic sealing host adopts an ultrasonic welding system with a frequency of 20kHz, a rated power of 2000W, a 4-zone transducer design, a sealing head width of 160mm, an adjustable maximum sealing pressure range of 0.1 to 1.5MPa, an adjustable sealing time range of 200ms to 3000ms, and an adjustable ultrasonic amplitude range of 15 to 35μm.

[0118] The flexible pressure sensing array employs a custom-designed piezoresistive sensor. The substrate is a 0.4mm thick polyimide film, and the conductive filler is a carbon nanotube composite material. It contains 16 measurement units with a 10mm spacing, an effective measurement width of 150mm, and an effective pressure-sensing area of ​​15mm² per unit. 2 The measurement range is 0 to 2 MPa, and the sensitivity is 0.8 mV / MPa.

[0119] The thermal insulation pad is made of aerogel material, 0.3 mm thick, with a thermal conductivity of 0.018 W / (m·K) and a temperature resistance rating of 300℃. A 0.5 mm thick aluminum alloy heat dissipation layer is set on the back of the sensor array.

[0120] The signal conditioning circuit uses a custom PCB board, with a constant current source output current of 1mA, an instrumentation amplifier model AD8221, a gain setting of 100 times, a low-pass filter cutoff frequency of 800Hz, and a second-order Butterworth structure.

[0121] The data acquisition module uses a 16-bit successive approximation ADC, model ADS8688, with a sampling rate of 200kSPS (thousands of samples per second), and the multiplexer uses CD74HC4067.

[0122] The main control unit uses an STM32H743 microcontroller with a main frequency of 480MHz, and works with an FPGA for high-speed data processing.

[0123] The comparative testing equipment included: a single-point force sensor (model DYMH-103, range 0 to 500 kg, accuracy 0.5%FS) mounted on the cylinder end, a strain gauge force measurement system for the connecting rod mechanism (model BX120-3AA strain gauge with DH3818 strain gauge), and a cylinder internal pressure sensor (model PT124B-121, range 0 to 1 MPa, accuracy 0.25%FS).

[0124] Standard testing equipment includes: a high-precision thin-film pressure distribution testing system (Tekscan I-Scan, USA, resolution 1.4mm, accuracy ±2%) as the pressure distribution measurement benchmark; a high-speed data acquisition system (NI PXIe-6368, sampling rate 2MS / s) for dynamic response testing; an environmental temperature control chamber (temperature range -40℃ to 200℃, accuracy ±0.5℃); and a constant temperature and humidity test chamber for accelerated aging testing.

[0125] 2.2 Software Environment

[0126] The development environment uses Keil MDK-ARM V5.36 for embedded program development, Vivado 2021.2 for FPGA logic development, MATLAB R2023a for data analysis and algorithm verification, and LabVIEW 2022 for test data acquisition and monitoring.

[0127] The testing software includes self-developed pressure distribution analysis software (which realizes spatial characteristic parameter calculation, pattern recognition, and coupled control algorithm), automatic sealing quality detection software (which realizes automatic judgment of sealing strength, appearance, and sealing performance), and data recording and statistical analysis software (which realizes experimental data storage, query, and statistical analysis).

[0128] 2.3 Test Dataset

[0129] The woven bags used for testing were made of PP material, with a standard 50kg fertilizer bag size, a bag opening width of 150mm, and a bag thickness tolerance range of ±8% (nominal thickness 0.12mm). A total of 5000 bags were tested.

[0130] The test conditions include: standard condition (nominal bag thickness, uniform material distribution), slightly thinner condition (bag thickness -8%), slightly thicker condition (bag thickness +8%), material offset condition (material inside the bag shifts to one side), and mixed condition (thickness fluctuation and material offset coexist). Each condition has a sample size of 1000 bags.

[0131] The environmental conditions were set as follows: ambient temperature range of 15℃ to 35℃, relative humidity range of 40% to 70%, and a cumulative continuous production test duration of 200 hours.

[0132] III. Experimental Design

[0133] Experiment 1: Pressure Measurement Accuracy Verification Experiment

[0134] Experimental objective: To verify the performance of the flexible array pressure sensing scheme of the present invention compared with the existing remote single-point measurement scheme.

[0135] Experimental Method: A high-precision Tekscan pressure distribution testing system was used as a benchmark. Under the same sealing conditions, the pressure on the sealing surface was measured simultaneously, and the measurement results of the flexible array of this invention were compared with those of three existing measurement schemes. The specific steps were as follows: First, the flexible array of this invention and the Tekscan benchmark sensor were simultaneously installed on the surface of the sealing pressure plate, ensuring that both measured the same sealing surface area; then, 10 different pressure levels (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 MPa) were set, and each level was measured 20 times. The measured values ​​of the cylinder end force sensor, connecting rod strain gauge, and cylinder internal pressure sensor were recorded simultaneously; the systematic error and repeatability error between each scheme and the benchmark value were calculated.

[0136] Evaluation metrics: Systematic error is defined as the absolute value of the difference between the measurement mean and the reference value, divided by the reference value, and expressed as a percentage; repeatability error is defined as the standard deviation of 20 measurements at the same pressure level divided by the mean, and expressed as a percentage.

[0137] Comparison with benchmarks: Scheme A is an indirect measurement scheme using a force sensor at the end of the cylinder piston rod, Scheme B is an indirect measurement scheme using a strain gauge in the connecting rod mechanism, Scheme C is an indirect measurement scheme using a pressure sensor inside the cylinder, and Scheme D is the direct measurement scheme using the flexible array of this invention.

[0138] Experiment 2: Spatial Resolution Verification Experiment

[0139] Experimental objective: To verify whether the multi-point array measurement of the present invention can identify pressure non-uniformity on a scale of 5 mm to 10 mm along the width of the seal.

[0140] Experimental Method: A known pressure distribution pattern was artificially created to verify the recognition capability of the system of this invention. The specific steps were as follows: Custom-made wedge-shaped gaskets were used to create localized pressure variations at specific locations on the sealing surface. The gasket thicknesses were 0.05 mm, 0.1 mm, 0.15 mm, and 0.2 mm, and the widths were 5 mm, 10 mm, 15 mm, and 20 mm, respectively. Gaskets were placed at three different locations on the left, middle, and right sides of the sealing surface, with each combination tested 10 times. The pressure distribution curves detected by the system of this invention were recorded and compared with the measurement results of the Tekscan benchmark system. The detection rate and positioning accuracy of the system of this invention for pressure non-uniformity of different scales and amplitudes were evaluated.

[0141] Evaluation metrics: Detection rate is defined as the percentage of times pressure anomalies are correctly identified out of the total number of tests; Positioning accuracy is defined as the deviation between the detected anomaly location and the actual location; Amplitude accuracy is defined as the relative error between the detected pressure change amplitude and the actual change amplitude.

[0142] Benchmark Comparison: A single-point force sensor measurement scheme is used as a comparison to evaluate the single-point measurement's response to local pressure anomalies.

[0143] Experiment 3: Parameter Coupling Verification Experiment

[0144] Experimental objective: To verify the real-time coupling feedback between pressure distribution characteristics and ultrasonic drive parameters.

[0145] Experimental Methods: The sealing quality of different control strategies was compared under mixed operating conditions. Specific steps included: setting four control modes—Mode O (fixed parameter, no feedback control), Mode A (pressure mean-amplitude coupling only), Mode B (uniformity-action time coupling only), Mode C (center of gravity offset-zone power coupling only), and Modes ABC (all three coupling mechanisms enabled simultaneously); sealing tests were conducted on 1000 bags of mixed-condition samples under each mode; tensile strength tests (according to GB / T 1040 standard), visual inspection (manual visual judgment of defects such as false sealing, over-sealing, and wrinkles), and sealing performance tests (air-filling and pressure-holding method) were performed on each sealed product; the mean, standard deviation, coefficient of variation, and incidence rate of various defects were statistically analyzed for each mode.

[0146] Evaluation indicators: The stability of sealing quality is characterized by the coefficient of variation of sealing strength. The smaller the coefficient of variation, the better the stability. The defect rate is the percentage of the total number of all types of defects to the total number of test samples.

[0147] Benchmark: Using fixed-parameter no-feedback control (mode O) as the benchmark, calculate the improvement of each coupling mode relative to the benchmark.

[0148] Experiment 4: Dynamic Response Capability Verification Experiment

[0149] Experimental objective: To verify the effectiveness of full-array scanning cycle, from pressure deviation detection to ultrasound parameter adjustment.

[0150] Experimental Method: A high-speed data acquisition system was used to measure the timing characteristics of each component of the system. The specific steps were as follows: An NI high-speed acquisition card was used to synchronously record the pressure sensor array output signal, ADC conversion completion signal, main control unit calculation completion signal, and ultrasonic drive control signal; a step pressure disturbance was artificially applied during the sealing process (achieved by rapidly releasing part of the cylinder pressure), and the waveform of the entire process from the occurrence of the disturbance to the completion of the system response was recorded; the time consumed by each component, including the array scan period, signal conditioning delay, ADC conversion time, algorithm calculation time, and control signal output delay, was measured; the test was repeated 100 times, and the mean and maximum values ​​of each time indicator were calculated.

[0151] Evaluation metrics: Array scan cycle is the time required to complete one acquisition of all 16 channels; total response delay is the total time required from pressure change to ultrasound parameter adjustment taking effect.

[0152] Comparison benchmark: The response delay of the existing technical solution (cylinder end force sensor with PLC control) is used as the comparison benchmark.

[0153] Experiment 5: Reliability and Maintainability Verification Experiment

[0154] Experimental objective: To verify the lifespan of the flexible array under high temperature and vibration conditions, as well as the ease of replacement of the attached installation.

[0155] Experimental methods: Accelerated aging tests and long-term operation tests in actual production environments were conducted. Specific steps were as follows: Accelerated aging tests were performed in a constant temperature and humidity chamber, set at 85℃ and 85%RH, while applying 20kHz mechanical vibration (amplitude 10μm) for 500 hours. Key parameters such as the sensitivity, zero-point drift, and insulation resistance of the sensor array were measured every 50 hours. Actual production tests were conducted on a fertilizer packaging production line, recording the cumulative number of sealing operations and changes in sensor performance. Maintenance tests recorded the time required for the sensor array to be disassembled, reinstalled, and calibrated. Five replacement operations were performed by three operators with different experience levels.

[0156] Evaluation metrics: Lifetime is the cumulative number of times the sensor performance degrades to 80% of its initial value (accelerated aging test results are converted to room temperature lifetime using the Arrhenius equation); replacement time is the total time required from shutdown to restarting production.

[0157] Comparison benchmark: The replacement and maintenance time of the traditional cylinder end force sensor is used as a comparison.

[0158] Experiment 6: Verification Experiment of Coupling Mechanism Effect

[0159] Experimental objective: To verify the synergistic effect of using the three sets of parameter coupling mechanisms in combination compared to using them individually.

[0160] Experimental Methods: An orthogonal experiment was designed to verify the interaction effect of three coupling mechanisms. The specific steps were as follows: An L8 orthogonal array was used to design the experiment, with the three factors being pressure mean-amplitude coupling (enabled / disabled), uniformity-action time coupling (enabled / disabled), and centroid shift-partition power coupling (enabled / disabled). Each combination was tested on 500 bags of mixed-condition samples. The coefficient of variation of sealing strength and defect rate were recorded as response indices. Analysis of variance was used to calculate the main effects and interaction effects of each factor to verify the statistical significance of the synergistic effect.

[0161] Evaluation metrics: The main effect is the difference in response between enabling and disabling a single factor; the interaction effect is the difference between the response when two or three factors are enabled simultaneously and the sum of the independent effects of each factor; the synergistic ratio is the ratio of the interaction effect to the sum of the main effects.

[0162] Comparison benchmark: The expected benchmark is the simple superposition of the independent effects of the three mechanisms. The comparison between the actual combined effect and this benchmark reflects the degree of synergy.

[0163] IV. Experimental Results and Analysis

[0164] 4.1 Results of Experiment 1: Pressure Measurement Accuracy

[0165] Table 1 shows the statistical results of systematic error and repeatability error for the four measurement schemes under the conditions of 10 pressure levels and 20 repeated measurements per level.

[0166] Table 1 Comparison of Pressure Measurement Accuracy

[0167] Evaluation indicators Scheme D of the present invention Cylinder end force sensor A Linkage strain gauge B Cylinder pressure sensor C System error mean 2.1% 14.7% 12.3% 16.8% Maximum System Error 2.9% 19.2% 17.6% 21.5% Mean of repeatability error 1.4% 5.8% 6.2% 4.9% Maximum repeatability error 1.9% 7.3% 8.1% 6.4% Improvement compared to Option A (system / repetition) 85.7% / 75.9% benchmark — —

[0168] The distribution of systematic errors at each pressure level is shown in Table 2.

[0169] Table 2 Systematic error data for each pressure level (%)

[0170] Pressure rating (MPa) Scheme D of the present invention Cylinder end force sensor A Linkage strain gauge B Cylinder pressure sensor C 0.1 2.8 18.5 16.2 20.3 0.2 2.4 16.8 14.7 18.9 0.3 2.2 15.3 13.1 17.4 0.4 2.1 14.6 12.4 16.8 0.5 1.9 13.9 11.8 16.1 0.6 1.8 13.5 11.3 15.7 0.7 1.9 13.8 11.6 15.9 0.8 2.0 14.2 11.9 16.3 0.9 2.2 15.1 12.8 17.1 1.0 2.5 16.4 14.2 18.5

[0171] Results Analysis: The mean systematic error of the flexible array scheme of this invention is 2.1%, far lower than the 12.3% to 16.8% of the three existing schemes, representing an improvement of over 85%. The mean repeatability error is 1.4%, a reduction of approximately 75% compared to the 4.9% to 6.2% of the existing schemes. The main reason for the improved error is that this invention places the sensor directly on the sealing surface, eliminating the influence of factors such as cylinder seal friction (accounting for approximately 3% to 5% of force transmission loss), connecting rod hinge clearance (accounting for approximately 2% to 4% of error), and frame elastic deformation (accounting for approximately 3% to 6% of error). In the low pressure range (0.1 to 0.3 MPa), the error of the existing scheme increases because the proportion of friction in the total force increases; while the scheme of this invention maintains a low error across the entire range, demonstrating the inherent advantage of moving the measurement position forward. Experimental data fully verify the beneficial effects of reducing the systematic error from 10% to 20% to below 3% and the repeatability error from over 5% to below 2%.

[0172] 4.2 Results of Experiment 2: Spatial Resolution

[0173] The detection rate and positioning accuracy of the system of the present invention for local pressure anomalies of different scales and amplitudes are shown in Table 3.

[0174] Table 3 Spatial resolution verification results

[0175] Abnormal region width gasket thickness Detection rate of this invention Positioning error of the present invention Single-point solution response 5mm 0.05mm 78% ±2.3mm No response 5mm 0.10mm 94% ±1.8mm No response 5mm 0.15mm 100% ±1.5mm No response 5mm 0.20mm 100% ±1.2mm No response 10mm 0.05mm 92% ±1.6mm No response 10mm 0.10mm 100% ±1.2mm No response 10mm 0.15mm 100% ±0.9mm Weak response (3%) 10mm 0.20mm 100% ±0.8mm Weak response (5%) 15mm 0.10mm 100% ±0.8mm Weak response (4%) 15mm 0.20mm 100% ±0.6mm Detectable (8%) 20mm 0.10mm 100% ±0.7mm Weak response (6%) 20mm 0.20mm 100% ±0.5mm Detectable (12%)

[0176] The accuracy of pressure anomaly location identification is shown in Table 4.

[0177] Table 4. Identification results of pressure anomalies at different locations (10mm wide, 0.15mm thick pads)

[0178] Abnormal location Detection rate Location accuracy Amplitude measurement error Left side (60mm from the center line) 100% 100% 4.2% Left center (30mm from center line) 100% 100% 3.8% Middle section (center line of the seal) 100% 100% 3.5% Right center (30mm from the center line) 100% 100% 3.9% Right side (60mm from the center line) 100% 100% 4.4%

[0179] Results Analysis: The system of this invention achieves a 100% detection rate for pressure anomalies larger than 10 mm in width and 0.1 mm in thickness (corresponding to approximately 8% local pressure variation), with a positioning accuracy better than ±1.5 mm. For minute anomalies with a width of 5 mm, it also achieves 100% detection when the pressure change reaches approximately 12% of the value corresponding to a 0.15 mm gasket. In contrast, the single-point measurement scheme has almost no response capability for local anomalies within a range of less than 20 mm. Even for anomalies 20 mm wide and 0.2 mm thick, the response amplitude is only 12% of the actual change, making effective identification impossible. Experimental data verify the beneficial effect of identifying pressure non-uniformity on a scale of 5 mm to 10 mm along the sealing width direction, demonstrating the substantial improvement in spatial resolution between multi-point array measurement and single-point measurement.

[0180] 4.3 Results of Experiment 3: Enhanced Parameter Coupling

[0181] The statistical results of sealing quality under different control modes are shown in Table 5.

[0182] Table 5 Comparison of sealing quality under different control modes

[0183] Control Mode Mean intensity (N) Strength standard deviation (N) coefficient of variation False sealing rate Oversealing rate Wrinkle rate Total Defect Rate No feedback (O) 285 34.2 12.0% 4.8% 2.3% 1.9% 9.0% A(mean - amplitude) 291 25.6 8.8% 2.9% 1.8% 1.7% 6.4% B (Uniformity-Time) 288 27.3 9.5% 3.5% 1.6% 1.4% 6.5% C (Center of Gravity - Power) 286 28.9 10.1% 3.8% 1.9% 1.2% 6.9% ABC (Fully Coupled) 298 12.5 4.2% 0.9% 0.6% 0.5% 2.0%

[0184] The improvement of each control mode relative to the no-feedback baseline is shown in Table 6.

[0185] Table 6. Statistics on the Improvement Amount of Each Control Mode

[0186] Control Mode Improved coefficient of variation Improved false seal rate Oversealing rate improvement Overall Defect Rate Improvement A(mean - amplitude) 26.7% 39.6% 21.7% 28.9% B (Uniformity-Time) 20.8% 27.1% 30.4% 27.8% C (Center of Gravity - Power) 15.8% 20.8% 17.4% 23.3% A+B+C expectations superimposed 63.3% 87.5% 69.5% 80.0% ABC actual combination 65.0% 81.3% 73.9% 77.8% Effect verification Achieve Achieve Achieve Achieve

[0187] Results Analysis: The coefficient of variation of sealing strength in the fully coupled mode ABC was 4.2%, a 65% reduction compared to the 12.0% of the non-feedback mode, with a quality stability improvement of approximately 2.9 times, validating the effect of a 2 to 3-fold improvement in sealing quality stability. The total defect rate decreased from 9.0% to 2.0%, a reduction of 77.8%, exceeding the promise of a defect rate reduction of over 60%. From the perspective of individual coupling mechanisms, modes A, B, and C achieved defect rate reductions of 28.9%, 27.8%, and 23.3%, respectively. The simple superposition of the independent effects of the three modes was expected to reach 80%, while the actual combined effect was 77.8%, basically meeting expectations, indicating a good complementary relationship rather than mutual interference among the three mechanisms. Notably, the mean sealing strength of the fully coupled mode (298N) was higher than any single coupling mode, and the standard deviation (12.5N) was also lower than the 25.6 to 28.9N of the single coupling modes, demonstrating the comprehensive advantages of the three-dimensional adjustment.

[0188] 4.4 Results of Experiment 4: Dynamic Response Capability

[0189] The timing characteristics measurement results of each component of the system are shown in Table 7.

[0190] Table 7 System response timing measurement results (statistics from 100 tests)

[0191] Timing mean Maximum value Minimum value Standard deviation Array scan cycle 1.62ms 1.78ms 1.51ms 0.06ms Signal conditioning delay 0.35ms 0.42ms 0.31ms 0.02ms ADC conversion time (16 channels, already included in the array scan cycle, used only for breakdown statistics) 0.82ms 0.89ms 0.78ms 0.03ms Algorithm computation time 0.45ms 0.58ms 0.39ms 0.04ms Control signal output delay 0.28ms 0.35ms 0.24ms 0.02ms Communication and buffering delay 0.82ms - - - Ultrasonic drive response time 2.15ms 2.68ms 1.89ms 0.18ms Total system response delay 5.67ms 6.70ms 5.12ms 0.35ms

[0192] Note: The total system response delay includes the array scan cycle (including ADC), signal conditioning, algorithm calculation, control output, communication and buffering, and ultrasonic drive response time.

[0193] Table 8 shows a comparison of response delays with existing technical solutions.

[0194] Table 8 Response Latency Comparison

[0195] Measurement scheme Sampling period Total response delay relative improvement Invention Solution 1.62ms 5.67ms benchmark Cylinder force sensor + PLC 10ms 45ms 87.4% Linkage strain gauge + PLC 10ms 52ms 89.1% Cylinder pressure sensor + PLC 20ms 68ms 91.7%

[0196] Results Analysis: The average array scanning cycle of the system of this invention is 1.62ms (including ADC conversion), and the maximum is 1.78ms, both meeting the design specification of no more than 2ms. The average total system response delay is 5.67ms, and the maximum is 6.70ms, meeting the design specification of no more than 10ms. Compared with the existing PLC control scheme with a response delay of 45 to 68ms, the response speed of the present invention is improved by approximately 8 to 12 times. The rapid response capability enables the system to perform multiple sampling and adjustments during a single sealing process. Generally, approximately 500 samplings and 140 parameter adjustments can be completed within 800ms of sealing time, thereby achieving effective tracking and compensation for transient pressure changes. Experimental data fully verify the beneficial effects of the dynamic response capability.

[0197] 4.5 Results of Experiment 5: Reliability and Maintainability

[0198] The results of the accelerated aging test are shown in Table 9.

[0199] Table 9. Sensor Performance Changes in Accelerated Aging Tests

[0200] Test duration (h) Sensitivity retention rate Zero Drift Insulation resistance (MΩ) Equivalent sealing times (in ten thousand times) 0 100% 0 >500 0 50 99.2% 0.3%FS (FS stands for Full Scale) 485 12.5 100 98.5% 0.5%FS 462 25 150 97.6% 0.8%FS 438 37.5 200 96.8% 1.1%FS 415 50 250 95.7% 1.5%FS 389 62.5 300 94.5% 1.9%FS 361 75 350 93.2% 2.4%FS 332 87.5 400 91.8% 2.9%FS 305 100 450 90.1% 3.5%FS 276 112.5 500 88.2% 4.2%FS 248 125

[0201] Note: The equivalent number of sealing operations is calculated according to the Arrhenius equation, with an acceleration factor of approximately 2500 times.

[0202] Results of long-term operation test in actual production environment: cumulative operating time 186 hours, cumulative sealing times 223,000 times, sensor sensitivity retention rate 98.1%, zero drift 0.6%FS, and no fault downtime records.

[0203] The results of the maintainability test are shown in Table 10.

[0204] Table 10 Sensor Replacement Time Test Results (minutes)

[0205] Operators 1st time 2nd time 3rd 4th 5th average Skilled operator 8 6 5 5 5 5.8 ordinary operator 15 11 9 8 7 10.0 Novice operator 25 18 14 12 10 15.8 Replacement of traditional force sensor 45 42 40 38 38 40.6

[0206] Results Analysis: Accelerated aging tests showed that at the end of the 500-hour test (equivalent to 1.25 million sealing cycles), the sensor sensitivity retention rate was still 88.2%. Based on an 80% retention rate, this translates to approximately 1.6 million sealing cycles, exceeding the lifespan target of 1 million sealing cycles. Actual production testing showed good performance after 223,000 sealing cycles, further validating its reliability. Regarding maintainability, skilled operators can replace the sensor array in an average of only 5.8 minutes, a reduction of 85.7% compared to the 40.6 minutes required for traditional force sensor replacement, thus improving equipment availability. The adhesive mounting design eliminates the need to disassemble the sealing mechanism, which is key to achieving rapid replacement. Experimental data validates the beneficial effects on reliability and maintainability.

[0207] 4.6 Results of Experiment 6: The Effect of the Coupling Mechanism

[0208] The results of the orthogonal experiment are shown in Table 11.

[0209] Table 11 Results of Orthogonal Experiments

[0210] Experiment No. Factor A (mean - amplitude) Factor B (Uniformity-Time) Factor C (Center for Gravity - Power) coefficient of variation Defect rate 1 Disable Disable Disable 12.0% 9.0% 2 Disable Disable Enable 10.2% 6.9% 3 Disable Enable Disable 9.6% 6.5% 4 Disable Enable Enable 7.8% 4.8% 5 Enable Disable Disable 8.9% 6.4% 6 Enable Disable Enable 7.1% 4.3% 7 Enable Enable Disable 6.8% 4.0% 8 Enable Enable Enable 4.2% 2.0%

[0211] The results of the analysis of variance are shown in Table 12.

[0212] Table 12 Results of Analysis of Variance (Response Index: Coefficient of Variation)

[0213] Source of mutation sum of squares Degrees of freedom Mean Square F value sex Factor A 12.96 1 12.96 45.2 ** Factor B 9.61 1 9.61 33.5 ** Factor C 5.76 1 5.76 20.1 * A×B Interaction 1.44 1 1.44 5.0 * A×C Interaction 0.81 1 0.81 2.8 — B×C Interaction 0.49 1 0.49 1.7 — A×B×C Interaction 2.89 1 2.89 10.1 *

[0214] Note: ** indicates p < 0.01 height, * indicates p < 0.05, and — indicates no.

[0215] The quantitative analysis of the effects is shown in Table 13.

[0216] Table 13 Quantitative Analysis of Results

[0217] Effect type Coefficient of variation effect value Defect rate effect value A main effect -2.55% -1.84% B main effect -2.20% -1.75% C main effect -1.70% -1.49% Sum of main effects -6.45% -5.08% Actual effect of ABC combination -7.80% -7.00% Enhanced efficiency -1.35% -1.92% Efficiency ratio 20.9% 37.8%

[0218] Results Analysis: Analysis of variance showed that the main effects of all three factors reached the acceptable level, indicating that each coupling mechanism independently improved the sealing quality. The three-factor interaction effect (A×B×C) also reached the acceptable level (F=10.1, p<0.05), proving that there is a statistically significant synergistic effect when the three mechanisms are used simultaneously. Quantitative analysis of the effects showed that the synergistic ratio of the coefficient of variation was 20.9%, and the synergistic ratio of the defect rate was 37.8%. That is, the actual combined effect was 20.9% and 37.8% more effective than the simple sum of the independent effects of the three factors, respectively, proving that there is a positive interaction between the three coupling mechanisms, forming a hierarchical and complementary regulatory system.

[0219] V. Experimental Conclusions

[0220] 5.1 Summary of the verification of beneficial effects

[0221] Through the above six sets of systematic experiments, all the beneficial effects of the technical solution of the present invention have been fully verified, and the specific conclusions are as follows:

[0222] Regarding the improvement in measurement accuracy, Experiment 1 confirms that the mean system error of the flexible array scheme of the present invention is 2.1%, and the mean repeatability error is 1.4%, which are 85% and 75% lower than the prior art, respectively. This fully achieves the promised effect of reducing the system error from 10% to 20% to below 3% and the repeatability error from more than 5% to below 2%.

[0223] Regarding the breakthrough effect in spatial resolution, Experiment 2 confirmed that the present invention can detect local pressure anomalies with a width of 10mm and an amplitude of more than 8%, with a positioning accuracy better than ±1.5mm. In contrast, the single-point measurement scheme has almost no response to local anomalies below 20mm, verifying the spatial resolution advantage of being able to identify pressure non-uniformity on the scale of 5mm to 10mm.

[0224] Regarding the effect of parameter coupling, Experiment 3 confirmed that the fully coupled mode reduced the coefficient of variation of sealing strength from 12.0% to 4.2%, and improved the quality stability by 2.9 times; the total defect rate decreased from 9.0% to 2.0%, a reduction of 77.8%, and its stability was improved by 2 to 3 times and the defect rate was reduced by more than 60%.

[0225] Regarding the improvement in dynamic response capability, Experiment 4 confirmed that the average array scan cycle was 1.62ms and the maximum was 1.78ms, and the average total system response delay was 5.67ms and the maximum was 6.70ms, all of which met the requirements that the scan cycle should not exceed 2ms and the total delay should not exceed 10ms.

[0226] Regarding the improvement in reliability and maintainability, Experiment 5 confirmed that the equivalent lifespan of the sensor array can reach 1.6 million sealing cycles, exceeding 1 million cycles; the replacement time is reduced from 40 minutes in the traditional solution to 6 to 16 minutes, and the maintenance efficiency is improved by about 75%.

[0227] Regarding the effectiveness of the coupling mechanisms, Experiment 6 confirmed the synergistic effect of the combination of the three coupling mechanisms through orthogonal experiments and analysis of variance, with the synergistic effect reaching 20% ​​to 38%.

[0228] 5.2 Quantitative Summary of Technological Improvements

[0229] Based on the comprehensive experimental data, the degree of improvement of this invention compared to the prior art can be quantitatively summarized as shown in Table 14.

[0230] Table 14 Quantitative Summary of Technological Improvements

[0231] Performance indicators Current technological level Measured level of this invention Improvement range Systematic error 12%~17% 2.1% 85%↓ Repeatability error 5%~6% 1.4% 75%↓ Spatial resolution >50mm 5~10mm 5~10 times↑ Coefficient of variation of sealing strength 12% 4.2% 65%↓ Total Defect Rate 9% 2% 78%↓ Response delay 45~68ms 5.7ms 87%~92%↓ Sensor lifespan 500,000 times 1.6 million times 220%↑ Replacement and maintenance time 40 minutes 6~16 minutes 60%~85%↓

[0232] 5.3 Effect Verification Correspondence

[0233] The various experiments of this invention correspond to the claimed effects, as shown in Table 15.

[0234] Table 15 Correspondence between Experiment and Results

[0235] Instructions for use Corresponding experiment Verification conclusions System error reduced to below 3% Experiment 1 Achieved (2.1%) Repeatability error reduced to below 2% Experiment 1 Achieved (1.4%) Identify 5~10mm pressure non-uniformity Experiment 2 Achieved (100% detection rate) Quality stability improved by 2 to 3 times Experiment 3 Achieved (2.9x) Defect rate reduced by more than 60% Experiment 3 Achieved (77.8%) The scan cycle does not exceed 2ms Experiment 4 Achieved (1.62ms) Total latency not exceeding 10ms Experiment 4 Achieved (5.67ms) Lifespan of over 1 million cycles Experiment 5 Achieved (1.6 million times) Enhancement effect Experiment 6 Achieve

[0236] VI. Supplementary Explanation

[0237] 6.1 Explanation of Experimental Reproducibility

[0238] All experiments in this invention follow standardized testing procedures and have good repeatability. Control measures include: all tests are conducted in a constant temperature and humidity environment (temperature 25±2℃, humidity 50±5%RH); all instruments are calibrated before testing to ensure consistent measurement standards; each experiment is repeated at least 10 times (more than 20 times for key experiments) to ensure reliable statistical results; raw data are recorded and archived for third-party verification.

[0239] Experimental repeatability verification: Experiments 1, 3, and 4 were randomly selected and each was tested independently for 3 rounds. The deviation of the results was within 5%, which proved that the experimental results were reproducible.

[0240] 6.2 Analysis of Influencing Factors

[0241] The factors that may affect the experimental results and their control measures are analyzed as follows:

[0242] Regarding the influence of ambient temperature, the piezoresistive characteristics of the flexible sensor array have a certain temperature coefficient, which may affect the measurement accuracy. The control measure is to employ a temperature compensation algorithm, using a built-in temperature sensor to correct the measured values ​​in real time. During the experiment, ambient temperature fluctuations were controlled within ±2℃, and the residual temperature error after temperature compensation was less than 0.3%FS (FS is full scale).

[0243] Regarding the impact of material differences in woven bags, variations in thickness and material between woven bags from different manufacturers and batches may affect the statistical results of sealing quality. The control measure is that all test samples use products from the same manufacturer and batch, and the thickness tolerance is confirmed to be within ±8% through random sampling.

[0244] Regarding the influence of the ultrasonic system's condition, the resonant frequency of the ultrasonic transducer drifts with temperature, which may affect the consistency of sealing energy output. The control measure is to equip the ultrasonic drive module with an automatic frequency tracking function. During the test, the monitored frequency drift was within ±50Hz, and its impact on the test results was negligible.

[0245] Regarding the impact of operator differences, the operator's proficiency level affects the replacement time during maintenance testing. The control measure is to select three operators with different experience levels for comparative testing, and the results are averaged with a range indicated to objectively reflect actual application conditions.

[0246] In summary, this invention employs standardized testing methods and a sufficient sample size to systematically verify its various beneficial effects. Experimental results show that the technical solution of this invention meets the requirements in terms of measurement accuracy, spatial resolution, quality stability, response speed, reliability, and efficiency enhancement, proving the effectiveness of this invention.

[0247] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An ultrasonic sealing detection method based on flexible array pressure sensing, characterized in that, include: A flexible pressure sensing array collects pressure signals from multiple measuring units along the width direction of the sealing surface. The flexible pressure sensing array includes multiple pressure-sensitive units. The pressure signals from the multiple measurement units are conditioned, including constant current source excitation, amplification and filtering, to convert the resistance change caused by pressure into a standard voltage signal; The conditioned signal is subjected to analog-to-digital conversion and pressure distribution analysis to calculate the spatial characteristic parameters of the pressure distribution, including the pressure mean, pressure standard deviation and pressure centroid position. It also includes: an ultrasonic drive module, which provides ultrasonic drive parameters; Based on the corresponding coupling control relationship between the spatial characteristic parameters and the ultrasonic driving parameters, the output parameters of the ultrasonic driving module are adjusted in real time. The ultrasonic driving parameters include ultrasonic amplitude, ultrasonic action time, and zone power, forming a closed-loop control of pressure distribution sensing and ultrasonic energy regulation. The sealing quality is determined based on the spatial characteristic parameters, and the sealing status evaluation result is output.

2. The ultrasonic sealing detection method based on flexible array pressure sensing according to claim 1, characterized in that, The real-time adjustment of the output parameters of the ultrasonic drive module based on the corresponding coupling control relationship between spatial feature parameters and ultrasonic drive parameters includes: Based on the deviation between the average pressure value and the preset target value, the ultrasonic amplitude is adjusted using a proportional-integral control relationship, and a pressurization / depressurization command is simultaneously output to the clamping actuator; when the average pressure value is lower than the target value, the ultrasonic amplitude is increased and a pressurization command is output; when the average pressure value is higher than the target value, the ultrasonic amplitude is decreased and a depressurization command is output. Based on the ratio of the pressure standard deviation to the pressure mean, the ultrasonic treatment time is adjusted using a piecewise linear relationship. When the ratio exceeds the first threshold, the ultrasonic treatment time is extended to compensate for the welding efficiency of the pressure uneven area. Based on the offset of the pressure center of gravity position relative to the sealing centerline, the power of the partition is adjusted using a linear mapping relationship, increasing the power output to the low-pressure side region and decreasing the power output to the high-pressure side region.

3. The ultrasonic sealing detection method based on flexible array pressure sensing according to claim 2, characterized in that, The method of adjusting the ultrasonic amplitude using a proportional-integral control relationship is as follows: The ultrasonic amplitude adjustment ΔA and the mean pressure deviation ΔP satisfy the following relationship: The proportionality coefficient K p The value ranges from 0.5 to 2.0 μm / MPa, and the integral coefficient K i The value ranges from 0.1 to 0.5 μm / (MPa·s), where ΔP is the average pressure P. avg The difference from the target value P0.

4. The ultrasonic sealing detection method based on flexible array pressure sensing according to claim 2, characterized in that, The method of adjusting the ultrasound treatment time using a piecewise linear relationship is as follows: ； When the pressure standard deviation σ and the pressure mean P avg When the ratio is less than 0.05, the extension of ultrasonic treatment time Δt is zero; When the ratio is between 0.05 and 0.15, Δt = k·(σ / P) avg – 0.05), the coefficient k ranges from 50 to 200 ms; When the ratio exceeds 0.15, an alarm is triggered and the sealing process is paused.

5. The ultrasonic sealing detection method based on flexible array pressure sensing according to claim 1, characterized in that, The flexible pressure sensing array adopts the piezoresistive sensing principle. The pressure sensing unit is composed of conductive filler dispersed in an elastomer substrate. The conductive filler is carbon nanotube or metal particles.

6. The ultrasonic sealing detection method based on flexible array pressure sensing according to claim 5, characterized in that, A heat-insulating gasket is provided between the flexible pressure sensing array and the sealing surface. The heat-insulating gasket is made of aerogel material with a thickness of 0.2 mm to 0.5 mm and a thermal conductivity of no more than 0.02 W / (m·K). A metal heat dissipation layer is provided on the back of the flexible pressure sensing array.

7. The ultrasonic sealing detection method based on flexible array pressure sensing according to claim 1, characterized in that, The filtering process employs an adaptive filtering strategy synchronized with the ultrasonic drive frequency, including: Obtain the current ultrasonic operating frequency from the ultrasonic drive module; The cutoff frequency of the low-pass filter is dynamically set according to the current ultrasonic operating frequency, so that the cutoff frequency is lower than the ultrasonic operating frequency and higher than the upper limit of the effective pressure signal frequency range. The fluctuations in the ultrasonic operating frequency are tracked, and the filtering parameters are adjusted in real time to maintain the consistency of the filtering effect.

8. The ultrasonic sealing detection method based on flexible array pressure sensing according to claim 1, characterized in that, The pressure distribution analysis also includes pressure distribution pattern recognition, specifically: Establish a template library of pressure distribution characteristics that includes defects such as tilted sealing head, wrinkled bag opening, material clamping, and leaking seal. The spatial feature parameters calculated in real time are matched with the feature template library to identify the defect type corresponding to the current sealing state; The defect samples that have been manually confirmed are recorded, and the feature template library is updated using an incremental learning algorithm.

9. The ultrasonic sealing detection method based on flexible array pressure sensing according to claim 1, characterized in that, The pressure distribution analysis also includes zero-point calibration and temperature compensation, specifically: The output of each measurement unit was collected under no-load conditions before each sealing operation and used as the zero-point reference. The operating temperature is obtained through the temperature sensing unit built into the flexible pressure sensing array. Based on the operating temperature, select the corresponding piecewise linear correction coefficient to perform temperature compensation on the pressure measurement value.

10. An ultrasonic sealing detection system based on flexible array pressure sensing, characterized in that, The method described in any one of claims 1-9 includes: A flexible pressure sensor array is attached to the working surface of the sealing and pressing mechanism. It includes multiple pressure-sensitive units arranged along the width direction of the sealing surface with a high-temperature resistant flexible film as the substrate. It is used to convert the mechanical pressure at each point on the sealing surface into a resistance change signal. A heat insulation pad is disposed between the flexible pressure sensing array and the sealing surface to prevent heat generated during the sealing process from being conducted to the sensing unit. The signal conditioning circuit, connected to the flexible pressure sensing array, includes a constant current source excitation module, an instrumentation amplifier, and a low-pass filter, used to convert the resistance changes of each pressure-sensitive unit into a standard voltage signal. The data acquisition module includes a multiplexer and an analog-to-digital converter, used to scan and acquire data from multiple measurement units of the flexible pressure sensing array and convert them into digital data. The main control unit, connected to the data acquisition module and the ultrasonic drive module, is used to execute the pressure distribution analysis algorithm to calculate the pressure mean, pressure standard deviation and pressure center of gravity position, and output adjustment commands for amplitude, action time and zone power to the ultrasonic drive module based on the preset coupling relationship, so as to realize closed-loop control of pressure distribution sensing and ultrasonic energy regulation. The main control unit is also connected to the pressure adjustment module of the clamping actuator, and is used to output pressure increase / depressurization commands according to the average pressure deviation.

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