Thickness detection system for nonwoven fabric production and detection method

Abstract

The application relates to the field of non-woven fabric detection, and particularly discloses a thickness detection system for non-woven fabric production, a support, a transmission roller, a laser detector, a tension adjusting module, and a tension detector and a tension adjusting device. The tension detector is used for detecting the real-time tension of the non-woven fabric in the longitudinal direction and the transverse direction respectively and outputting a second detection signal. The tension detector is in signal connection with the tension adjusting device. The tension adjusting device comprises a signal processor. The signal processor receives the second detection signal and compares the second detection signal with a preset tension threshold value to select a current working mode. According to the current working mode, the first detection signal is converted into a tension adjusting instruction according to a mapping relationship corresponding to the mode, so as to adjust the tension of the non-woven fabric in the longitudinal direction and / or the transverse direction. The application has the beneficial effect of providing the thickness detection system for non-woven fabric production which can adjust the tension in real time.

Description

Technical Field

[0001] This application relates to the field of nonwoven fabric testing, and in particular to a thickness testing system for nonwoven fabric production. Background Technology

[0002] Nonwoven fabric (also known as non-woven cloth) is a type of fabric formed without spinning or weaving. It is typically made from materials such as polyester fibers through processes like needle punching, hydroentangling, or thermal bonding. It features moisture resistance, breathability, flexibility, and lightweight properties, and can be widely used in various industries including medical and health care, filter materials, and clothing linings. Thickness is one of the key indicators of nonwoven fabric product quality, directly affecting the product's physical properties and performance. Therefore, accurate and efficient detection of the finished product's thickness is a crucial aspect of quality control during nonwoven fabric production. Currently, the following methods are mainly used for nonwoven fabric thickness detection.

[0003] One method is offline sampling inspection, where quality inspectors periodically take samples from the production line and measure them under laboratory conditions using a contact thickness gauge (such as a digital fabric thickness gauge). While this method offers high measurement accuracy, it suffers from detection lag, cannot reflect real-time thickness fluctuations during continuous production, and carries the risk of missed detections during sampling inspection.

[0004] Secondly, there are online detection methods. Related technologies already include solutions for online thickness detection of nonwoven fabrics using infrared or laser thickness gauges. For example, an infrared thickness gauge can be installed on a horizontal support column, and its left and right movement can be controlled by an electric guide rail to achieve multi-point sampling and detection of wide-width nonwoven fabrics; alternatively, a laser displacement sensor can be used to collect thickness data of the nonwoven fabric surface in a non-contact manner. However, existing online thickness detection systems for nonwoven fabrics still have many shortcomings. First, as a material with a soft and easily deformable fiber structure, the tension state of nonwoven fabric during transmission has a significant impact on the thickness measurement results. When the tension of the nonwoven fabric is insufficient, the loose fabric surface will lead to an increase in the actual detection cross-section, resulting in an overestimation of the thickness measurement value; when the tension is too high, the fabric surface will be stretched and thinned, leading to an underestimation of the measurement value. Most existing thickness detection devices do not fully consider the interference of tension factors on detection accuracy, resulting in insufficient reliability of measurement data. Second, as nonwoven fabric production lines develop towards higher speeds and wider widths, factors such as changes in production line speed and roll diameter will cause uneven tension distribution in the width and length directions of the nonwoven fabric, further exacerbating the error in thickness detection. Furthermore, existing thickness detection systems typically only have a single detection function and lack the ability to dynamically adjust detection conditions (such as tension state), making it difficult to maintain optimal detection conditions throughout continuous production. Therefore, it is necessary to design a new thickness detection system that can effectively suppress the impact of tension fluctuations on measurement accuracy while detecting the thickness of nonwoven fabrics in real time. Summary of the Invention

[0005] This application provides a thickness detection system for nonwoven fabric production, which solves the problem that the existing technology cannot implement the function of dynamically adjusting the tension state of nonwoven fabric. It realizes real-time detection of nonwoven fabric thickness and can effectively suppress the influence of tension fluctuation on measurement accuracy.

[0006] Example 1 The thickness detection system for nonwoven fabric production provided in this application is used to detect the thickness of nonwoven fabric; the technical solution is as follows: including: a bracket, which is fixedly set after the output end of the nonwoven fabric production line to support the entire detection unit; The transfer roller, mounted on the support, is used to receive and guide the nonwoven fabric at a constant linear speed. A laser detector is used to detect the current thickness of nonwoven fabric and outputs a first detection signal. Tension adjustment module, including tension detector and tension adjustment device; The tension detector is used to detect the real-time tension of the nonwoven fabric in the longitudinal and transverse directions, and outputs a second detection signal. The tension detector is connected to the tension adjustment device. The tension adjustment device includes a signal processor, which receives the second detection signal and compares it with a preset tension threshold to select the current working mode. Based on the current working mode, the signal processor converts the first detection signal into a tension adjustment command according to the mapping relationship corresponding to the mode, so as to adjust the tension of the nonwoven fabric in the longitudinal and / or transverse directions.

[0007] This invention achieves closed-loop coordinated control of thickness detection and tension adjustment by using a tension detector to collect real-time tension forces (second detection signals) in the longitudinal and transverse directions of nonwoven fabric. A signal processor then uses these signals as feedforward / feedback variables to perform pattern-based correction on the thickness signal output by the laser detector. This effectively compensates for the adverse effects of tension fluctuations caused by the soft and easily deformable structure of nonwoven fabric fibers on thickness measurement accuracy. It avoids the measurement deviations of "falsely high" or "falsely low" thickness data caused by tension changes in traditional methods, significantly improving the authenticity and reliability of thickness detection data during continuous production.

[0008] Optionally, the transfer rollers are two in number and are mounted on a support that are movable relative to each other; The adjustment device also includes a signal processor for receiving a second detection signal and comparing it with a preset tension threshold, selecting the current working mode and / or converting the first detection signal into a tension adjustment command according to the mapping relationship corresponding to the current working mode based on the current working mode. The output commands include: preset target output tension, data viewing, data storage, unit switching, tension direction adjustment, and locking or blocking the first detection signal and / or the second detection signal.

[0009] Optional, the tension adjustment device includes: The longitudinal tensioning roller is rotatably mounted on the support. A transverse tensioning wheel is mounted on the side wall of the bracket; Loading plate, used to load the lateral tensioner; Drive components provide power for the movement of the lateral tensioner and loading plate; The transverse tensioning rollers are located on both sides of the transmission roller along the longitudinal direction, and two longitudinal tensioning rollers are provided on each side; the loading plate is moved and mounted on the support along the longitudinal direction; multiple transverse tensioning rollers are provided and arranged in a row at intervals along the length of the loading plate; the drive component is connected to the signal processing module to receive and execute output commands.

[0010] Optionally, the driver components include: An electric telescopic rod is connected to the longitudinal tension roller; Electromagnet, mounted on a support; Magnetic components are mounted on the loading plate; The electric telescopic rod / electromagnet is connected to the signal processing module to execute output commands; the electromagnet generates a magnetic field that attracts / repels the magnetic component when energized; the magnetic component is positioned opposite to the electromagnet.

[0011] Optionally, the sidewalls of the bracket form guide grooves for the movement of the loading plate; The loading plate is movably positioned within the guide groove; An electromagnet is installed at the bottom of the guide groove; the bottom of the guide groove is connected to the loading plate by an elastic element.

[0012] Optionally, the signal processing module includes: The mode selection unit receives the second detection signal and compares it with a preset tension threshold range. When the second detection signal is lower than the lower threshold, the first working mode is selected; when the second detection signal is higher than the upper threshold, the second working mode is selected; otherwise, the third working mode is selected. The instruction conversion unit converts the first detection signal into an output instruction according to the corresponding mapping relationship based on the currently selected working mode; In different working modes, the mapping relationship between the first detection signal and the output command is different.

[0013] Optionally, an elastic buffer layer is provided on the outer circumferential surface of the transverse tensioning wheel, which is used to contact the edge of the nonwoven fabric; Furthermore, each transverse tensioning wheel is independently connected to the loading plate via a telescopic rod. The telescopic rod extends and retracts perpendicular to the length of the loading plate to adjust the pressure exerted by the transverse tensioning wheel on the side of the nonwoven fabric.

[0014] Optionally, the signal processor is configured to compare the received second detection signal with a tension threshold interval [TL, TH] pre-stored in a register; When the second detection signal is less than TL, select "Low Tension Compensation Mode"; When the second detection signal > TH, select "High Tension Release Mode"; When TL ≤ the second detection signal ≤ TH, select "steady-state fine-tuning mode"; Furthermore, the mapping relationship between the first detection signal and the tension adjustment command is different under different working modes, and the amplitude, direction and rate of the adjustment command corresponding to the same thickness deviation signal are different.

[0015] Optionally, the signal processor may have a built-in mode selection unit and instruction conversion unit. The mode selection unit receives the second detection signal and compares it with a multi-interval dynamic tension threshold, using a hysteresis comparator to avoid frequent mode switching near the threshold boundary; When the second detection signal is lower than the lower threshold (TL-Δ), the first working mode, i.e., active boosting mode, is selected; when the second detection signal is higher than the upper threshold (TH+Δ), the second working mode, i.e., active de-boosting mode, is selected; otherwise, the third working mode, i.e., follow mode, is selected. The instruction conversion unit stores three independent mapping relationships. Different control strategies are used in different working modes to convert the first detection signal into a tension adjustment instruction.

[0016] A thickness detection method for nonwoven fabric production, applicable to the aforementioned thickness detection system for nonwoven fabric production, includes the following steps: A1. The non-woven fabric is transported at a uniform speed by a transfer roller. A2. Collect the thickness data of the nonwoven fabric in real time using a laser detector to generate the first detection signal; A3. The real-time tension of the nonwoven fabric in the longitudinal and / or transverse directions is detected by a tension detector to generate a second detection signal; A4. The signal processor receives the second detection signal and compares it with a preset tension threshold to select the current working mode. Based on the selected current working mode, the mapping relationship stored in the mode is called to convert the first detection signal into a tension adjustment command. In different working modes, the mapping relationship between the first detection signal and the tension adjustment command is different, so that the amplitude and / or rate of the adjustment command corresponding to the same thickness deviation signal are different in different modes. A5. According to the tension adjustment command, drive the tension adjustment device to adjust the tension of the nonwoven fabric in the longitudinal and / or transverse directions.

[0017] In summary, this application includes at least one of the following beneficial technical effects: 1. This invention achieves closed-loop coordinated control of thickness detection and tension adjustment by using a tension detector to collect real-time tension forces (second detection signals) in the longitudinal and transverse directions of the nonwoven fabric, and by using a signal processor as a feedforward / feedback variable to perform pattern correction on the thickness signal output by the laser detector. This effectively compensates for the adverse effects of tension fluctuations caused by the soft and easily deformable structure of nonwoven fabric fibers on the accuracy of thickness measurement, avoiding the measurement deviations of "falsely high" or "falsely low" thickness data caused by tension changes in traditional solutions, and significantly improving the authenticity and reliability of thickness detection data in continuous production processes. 2. This invention presets a tension threshold range ([TL, TH]) and selects a "low tension compensation mode," "high tension release mode," or "steady-state fine-tuning mode" based on comparison results. Different mapping relationships (such as nonlinear PID parameters, fuzzy rules, or different gain coefficients) are configured for the first detection signal under different operating modes. This allows the same thickness deviation signal to trigger appropriate adjustment commands under different tension conditions—high-gain rapid compensation at low tension and gradual, micro-adjustment to avoid overshoot in steady-state conditions. This intelligent segmented control strategy significantly improves the system's adaptability to complex conditions such as production line speed changes and raw material batch differences. 3. This invention achieves point-to-point independent compensation for the lateral tension of nonwoven fabric at different width positions (from edge to center) by arranging multiple transverse tensioning wheels at equal intervals along the length of the loading plate, and by independently connecting each transverse tensioning wheel to the loading plate through a telescopic rod. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application; Figure 2 This is a schematic diagram of the overall structure of the electric telescopic rod and the longitudinal tensioning roller according to an embodiment of this application; Figure 3This is a schematic diagram of the overall structure of the support plate and the transverse tensioning wheel according to an embodiment of this application; Figure 4 This is an exploded view of the support plate and the transverse tensioning wheel according to an embodiment of this application.

[0019] Reference numerals: 1. Support frame; 2. Transfer roller; 3. Laser detector; 4. Longitudinal tension roller; 5. Transverse tension wheel; 6. Loading plate; 7. Electric telescopic rod; 8. Electromagnet; 9. Magnetic component. Detailed Implementation

[0020] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0021] It should also be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0022] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0023] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0024] This disclosure will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] This application discloses a thickness detection system for nonwoven fabric production. This system is suitable for downstream processes of high-speed, wide-width nonwoven fabric production lines, and is used to monitor the thickness of nonwoven fabric in real time and accurately during continuous production while dynamically maintaining optimal detection conditions. It includes: a support frame 1, a transmission roller 2, a laser detector 3, and a tension adjustment module. Specifically, the support frame 1 is integrally welded from carbon steel, forming a gantry structure. It is fixed to the output end of the nonwoven fabric production line with anchor bolts and is used to mount the entire detection unit. At least one set of transmission rollers 2 is horizontally mounted in the middle of the support frame 1. The rollers are covered with anti-slip rubber and consist of a drive roller and a driven roller. They are used to receive the nonwoven fabric output from the upstream production line, driving the nonwoven fabric to be transmitted horizontally at a constant speed. The transmission rate is synchronized with the main speed of the production line, meeting the adaptation requirements of various conventional nonwoven fabric production lines. The laser detector 3 is mounted on the crossbeam of the bracket 1, preferably using a through-beam or reflective laser displacement sensor; the laser emission mode is perpendicular to the nonwoven fabric, used to collect thickness data of multiple sampling points on the nonwoven fabric in real time, and generate the corresponding first detection signal; the tension adjustment module is used to eliminate the adverse effects of tension fluctuations caused by the soft and easily deformable fiber structure of the nonwoven fabric on the thickness measurement accuracy, including a tension detector and a tension adjustment device; The tension detector preferably consists of two sets of multi-dimensional force sensors, respectively positioned at the longitudinal (i.e., travel direction) edge and the transverse (i.e., width direction) edge of the nonwoven fabric. Each set of force sensors senses the real-time tension of the nonwoven fabric in the longitudinal and transverse directions through non-contact (such as air-floating guide wheels) or low-friction contact rollers, and outputs a second detection signal. The tension detector and the tension adjustment device are connected via a signal line or an industrial wireless network. The adjustment device responds to the second detection signal to adjust the tension of the nonwoven fabric in the longitudinal and / or transverse directions. Through the above scheme, the adverse effects of tension fluctuations caused by the soft and easily deformable fiber structure of the nonwoven fabric on the accuracy of thickness measurement can be mitigated.

[0026] Specifically, the adjustment device also includes a signal processor, which receives a second detection signal, compares it with a preset tension threshold, selects the current working mode and / or, based on the current working mode, converts the first detection signal into a tension adjustment command according to the mapping relationship corresponding to the mode. More specifically, the signal processor is configured to: first, compare the received second detection signal with a tension threshold range [TL, TH] pre-stored in a register. Based on the comparison result, the processor selects the current operating mode; specifically: When S2 < TL, the nonwoven fabric tension is determined to be insufficient, and the "low tension compensation mode" is selected. When S2 > TH, it is determined that the tension of the nonwoven fabric is too high, and the "high tension release mode" is selected. When TL ≤ S2 ≤ TH, the tension is deemed appropriate, and the "steady-state fine-tuning mode" is selected.

[0027] Subsequently, based on the selected operating mode, the signal processor calls the mapping functions (e.g., nonlinear PID parameter tables, fuzzy control rule bases, or linear proportional coefficients) stored in different storage areas to convert the first detection signal into a specific tension adjustment command in real time; under different operating modes, the amplitude, direction, and rate of the adjustment command corresponding to the same thickness deviation signal are different.

[0028] For example, in "low tension compensation mode", if the thickness is detected to be too large (which may be due to insufficient tension causing the nonwoven fabric to loosen and the actual cross-section to increase), the adjustment command will quickly increase the longitudinal and / or transverse tension with a high gain; while in "steady-state fine adjustment mode", the same signal of excessive thickness will only trigger a very small amplitude of gradual tension adjustment to avoid overshoot. Specifically, the types of output commands include, but are not limited to: preset target output tension, data viewing, data storage, unit switching, tension direction adjustment, and locking or shielding the first and / or second detection signals under special working conditions; among them, the locking or shielding function is particularly critical during system calibration or maintenance to prevent accidental adjustment; Through the above settings, this system achieves closed-loop coordinated control of thickness detection and tension adjustment, which significantly improves the adaptability of thickness detection under working conditions and the reliability of data.

[0029] In this embodiment, two transfer rollers 2 are configured, namely a first transfer roller 2 and a second transfer roller 2. These two transfer rollers 2 are relatively movable on the support 1 via a linear slide rail and a lead screw mechanism. By adjusting the axial distance between the two rollers, the basic wrap angle and average tension of the nonwoven fabric in the detection area can be macroscopically adjusted. Through the above solution, the problem of uneven tension distribution of nonwoven fabric caused by changes in production line speed or roll diameter can be solved. Specifically, the tension adjustment device also includes: longitudinal tension roller 4, transverse tension wheel 5, loading plate 6, and drive assembly; In this embodiment, there are four longitudinal tension rollers 4, which are rotatably mounted on the side wall of the support 1. From the direction of travel of the nonwoven fabric, two longitudinal tension rollers 4 are located on the inlet side (upstream) of the transmission roller 2 assembly, and the other two are located on the outlet side (downstream), and the two tension rollers on each side are staggered vertically. The nonwoven fabric passes around these tension rollers in an "S" shape, thereby forming a stable friction wrap angle. In this embodiment, each of the two opposite sidewalls of the bracket 1 is provided with a guide groove extending in the vertical direction (i.e., longitudinal direction); the two guide grooves form a guide path by their concave portions in opposite directions; the loading plate 6 is embedded in the guide groove and can move along the guide path; the bottom of the guide groove and the loading plate 6 are connected by an elastic element, preferably a return spring, to give the loading plate 6 an elastic left that keeps it away from the nonwoven fabric; more specifically, each loading plate 6 has multiple transverse tensioning wheels 5 arranged at equal intervals along its length direction (i.e., transversely perpendicular to the direction of travel of the nonwoven fabric); the outer circumferential surface of these transverse tensioning wheels 5 is covered with an elastic buffer layer of rubber or polyurethane material to gently contact the edge of the nonwoven fabric and prevent fiber damage; the buffer layer can improve the friction between the transverse tensioning wheels 5 and the surface of the nonwoven fabric.

[0030] In this embodiment, the drive assembly is used to provide power for the movement of the transverse tensioning roller and the loading plate 6; the drive assembly includes: an electric telescopic rod 7, an electromagnet 8, and a magnetic component 9; wherein, each longitudinal tensioning roller 4 is independently connected to the support 1 via an electric telescopic rod 7, the telescopic direction of which is perpendicular to the bottom surface of the support 1, and the longitudinal tensioning roller 4 and the electric telescopic rod 7 are connected by bearings; this allows for point-to-point compensation for longitudinal tension fluctuations at different widths of the nonwoven fabric; A magnetic component 9, preferably a permanent magnet, is installed on the loading plate 6; an electromagnet 8 is positioned in the guide groove and opposite to the magnetic component 9; when the electromagnet 8 is energized, it can generate a magnetic field that moves the permanent magnet away from or towards the electromagnet 8; thus, the width direction can be adjusted during the nonwoven fabric transport process; Specifically, all electric telescopic rods 7 and electromagnets 8 are connected to a signal processor (i.e., the controller in the aforementioned tension adjustment device) to receive and execute the output commands. When it is necessary to increase the longitudinal tension, the signal processor controls the electric telescopic rods 7 to extend, increasing the pressure depth of the tension roller on the nonwoven fabric. When it is necessary to increase the transverse tension, the signal processor outputs a PWM current with a specific duty cycle to the electromagnet 8 according to a preset program, causing the electromagnet 8 to generate a magnetic field that attracts the magnetic component 9, thereby driving the loading plate 6 and the transverse tensioning wheel 5 on it to move towards the center of the nonwoven fabric.

[0031] In this embodiment, based on the above scheme, a mode selection unit and an instruction conversion unit are constructed internally by software or firmware within the signal processor. The mode selection unit receives the second detection signal and compares it with a dynamic tension threshold spanning multiple intervals. Unlike a simple upper / lower limit, this unit employs a hysteresis comparator to avoid frequent mode switching near the threshold boundaries. When the second detection signal is below the lower threshold (TL-Δ), the first operating mode (active boosting mode) is selected; when the second detection signal is above the upper threshold (TH+Δ), the second operating mode (active deceleration mode) is selected; otherwise, the third operating mode (follower mode) is selected. The instruction conversion unit stores three independent mapping relationships, for example: 1. In the first working mode, a proportional control with a gain coefficient K1 = 2.5 is used, and the output command is: Dout = 2.5 × (Ttarget - Tcurrent); 2. In the second working mode, a proportional-derivative (PD) control with a gain coefficient K2 = 0.8 is adopted, and the output command is: Dout = 0.8·(Tcurrent-Ttarget) + Kd·dtd(Tcurrent); 3. In the third operating mode, proportional-integral (PI) control with a gain coefficient K3 = 1.0 is adopted; In addition, the signal processor includes a self-learning optimization module. This module communicates with the main control system (PLC or DCS) of the production line to obtain auxiliary variables such as the current production speed of the nonwoven fabric, raw material batch number, and ambient temperature and humidity in real time. The self-learning optimization module utilizes lightweight online machine learning algorithms (e.g., recursive least squares) to continuously adjust the mapping parameters (such as K1, K2, Kd, ​​etc.) under various working modes during the continuous operation of the production line. Specifically, this module uses minimizing the variance of the thickness signal output by the laser detector 3 and minimizing the energy consumption of the tension adjustment device as dual-objective optimization functions, continuously fine-tuning the control parameters. After a period of learning, the system can automatically match the optimal tension-thickness adjustment strategy for specific types and speeds of nonwoven fabric. To handle emergency shutdowns or fabric insertion operations, the signal processor also integrates a "one-click shielding" function. When it receives an external emergency stop signal or a specific instruction from the control panel, the signal processor locks all tension adjustment instructions and simultaneously shields the output signal of the laser detector 3 to prevent false alarms or malfunctions during non-production operations.

[0032] Example 2 A thickness detection method for nonwoven fabric production, applicable to the thickness detection system for nonwoven fabric production described in the above embodiment, includes the following steps: A1. The non-woven fabric is transported at a uniform speed by a transfer roller. A2. Collect the thickness data of the nonwoven fabric in real time using a laser detector to generate the first detection signal; A3. The real-time tension of the nonwoven fabric in the longitudinal and / or transverse directions is detected by a tension detector to generate a second detection signal; A4. The signal processor receives the second detection signal and compares it with a preset tension threshold to select the current working mode. Based on the selected current working mode, the mapping relationship stored in the mode is called to convert the first detection signal into a tension adjustment command. In different working modes, the mapping relationship between the first detection signal and the tension adjustment command is different, so that the amplitude and / or rate of the adjustment command corresponding to the same thickness deviation signal are different in different modes. A5. According to the tension adjustment command, drive the tension adjustment device to adjust the tension of the nonwoven fabric in the longitudinal and / or transverse directions.

[0033] In the mode determination and instruction conversion step, the nonwoven fabric detection signal processor uses a hysteresis comparator to compare the second detection signal of the nonwoven fabric with a dynamic tension threshold of multiple intervals to select the current working mode. When the second detection signal of the nonwoven fabric detection is lower than the lower threshold (TL-Δ), the first working mode, i.e., the active force boosting mode, is selected. When the second detection signal of the nonwoven fabric detection is higher than the upper threshold (TH+Δ), the second working mode, namely the active force reduction mode, is selected. Otherwise, select the third working mode, namely the follow mode; By setting the hysteresis comparator for nonwoven fabric detection, frequent switching of the working mode is avoided when the second detection signal for nonwoven fabric detection fluctuates near a single threshold boundary. In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A thickness detection system for nonwoven fabric production, used to detect the thickness of nonwoven fabrics; characterized in that, include: The bracket is fixedly installed at the output end of the nonwoven fabric production line to support the entire testing unit; A transfer roller, mounted on the support, is used to receive and guide the nonwoven fabric to be transferred at a constant linear speed; A laser detector is used to detect the current thickness of nonwoven fabric and outputs a first detection signal. Tension adjustment module, including tension detector and tension adjustment device; The tension detector is used to detect the real-time tension of the nonwoven fabric in the longitudinal and transverse directions, and outputs a second detection signal. The tension detector is connected to the tension adjustment device. The tension adjustment device includes a signal processor, which receives the second detection signal and compares it with a preset tension threshold to select the current working mode. Based on the current working mode, the signal processor converts the first detection signal into a tension adjustment command according to the mapping relationship corresponding to the mode, so as to adjust the tension of the nonwoven fabric in the longitudinal and / or transverse directions.

2. The thickness detection system for nonwoven fabric production according to claim 1, characterized in that: The transmission rollers are two in number and are movably mounted on the support. The adjustment device further includes a signal processor, which is used to receive the second detection signal, compare it with a preset tension threshold, select the current working mode and / or, based on the current working mode, convert the first detection signal into a tension adjustment command according to the mapping relationship corresponding to the mode. The output commands include: preset target output tension, data viewing, data storage, unit switching, tension direction adjustment, locking or blocking the first detection signal and / or the second detection signal.

3. The thickness detection system for nonwoven fabric production according to claim 2, characterized in that: The tension adjusting device includes: A longitudinal tensioning roller is rotatably mounted on the bracket; A transverse tensioning wheel is mounted on the side wall of the bracket; Loading plate, used to load the transverse tensioner; A drive assembly provides power for the movement of the lateral tension wheel and the loading plate; The transverse tensioning rollers are located on both sides of the transmission roller along the longitudinal direction, and two longitudinal tensioning rollers are provided on each side; the loading plate is movably mounted on the bracket along the longitudinal direction; multiple transverse tensioning rollers are provided and arranged in a row at intervals along the length of the loading plate; the drive component is signal-connected to the signal processing module, and receives and executes the output command.

4. The thickness detection system for nonwoven fabric production according to claim 3, characterized in that: The driving component includes: An electric telescopic rod connects the longitudinal tensioning roller and the bracket; An electromagnet is mounted on the bracket; Magnetic components are disposed on the loading plate; The electric telescopic rod and the electromagnet are both connected to the signal processing module to execute the output command; the electromagnet, when energized, can generate a magnetic field that attracts / repels the magnetic component; the magnetic component is arranged opposite to the electromagnet.

5. The thickness detection system for nonwoven fabric production according to claim 4, characterized in that: The sidewall of the bracket forms a guide groove for the movement of the loading plate; The loading plate is movably disposed within the guide groove; The electromagnet is installed at the bottom of the guide groove; the bottom of the guide groove is connected to the loading plate by an elastic element.

6. The thickness detection system for nonwoven fabric production according to claim 5, characterized in that: The signal processing module includes: The mode selection unit receives the second detection signal and compares it with a preset tension threshold range. When the second detection signal is lower than the lower threshold, it selects the first working mode; when the second detection signal is higher than the upper threshold, it selects the second working mode; otherwise, it selects the third working mode. The instruction conversion unit converts the first detection signal into the output instruction according to the corresponding mapping relationship based on the currently selected working mode; In different operating modes, the mapping relationship between the first detection signal and the output command is different.

7. The thickness detection system for nonwoven fabric production according to claim 6, characterized in that: The outer circumferential surface of the transverse tensioning wheel is provided with an elastic buffer layer, which is used to contact the edge of the non-woven fabric. Furthermore, each transverse tensioning wheel is independently connected to the loading plate via a telescopic rod, the telescopic rod extending perpendicular to the length of the loading plate, in order to adjust the clamping force of the transverse tensioning wheel on the side of the nonwoven fabric.

8. The thickness detection system for nonwoven fabric production according to claim 7, characterized in that: The signal processor is configured to compare the received second detection signal with a tension threshold interval [TL, TH] pre-stored in a register; When the second detection signal is less than TL, select "Low Tension Compensation Mode"; When the second detection signal > TH, select "High Tension Release Mode"; When TL ≤ the second detection signal ≤ TH, select "steady-state fine-tuning mode"; Furthermore, the mapping relationship between the first detection signal and the tension adjustment command is different under different working modes, and the amplitude, direction and rate of the adjustment command corresponding to the same thickness deviation signal are different.

9. The thickness detection system for nonwoven fabric production according to claim 8, characterized in that: The signal processor internally includes a mode selection unit and an instruction conversion unit; The mode selection unit receives the second detection signal and compares it with a multi-interval dynamic tension threshold, using a hysteresis comparator to avoid frequent mode switching near the threshold boundary; When the second detection signal is lower than the lower threshold (TL-Δ), the first working mode, i.e., active boosting mode, is selected; when the second detection signal is higher than the upper threshold (TH+Δ), the second working mode, i.e., active de-boosting mode, is selected; otherwise, the third working mode, i.e., follow mode, is selected. The instruction conversion unit stores three independent mapping relationships and uses different control strategies in different working modes to convert the first detection signal into the tension adjustment instruction.

10. A thickness detection method for nonwoven fabric production, characterized in that, The thickness detection system for nonwoven fabric production according to any one of claims 1-9 comprises the following steps: A1. The non-woven fabric is transported at a uniform speed by a transfer roller. A2. Collect the thickness data of the nonwoven fabric in real time using a laser detector to generate the first detection signal; A3. The real-time tension of the nonwoven fabric in the longitudinal and / or transverse directions is detected by a tension detector to generate a second detection signal; A4. The signal processor receives the second detection signal, compares the second detection signal with a preset tension threshold to select the current working mode; and, based on the selected current working mode, calls the mapping relationship stored in the mode to convert the first detection signal into a tension adjustment command; wherein, in different working modes, the mapping relationship between the first detection signal and the tension adjustment command is different, so that the amplitude and / or rate of the adjustment command corresponding to the same thickness deviation signal are different in different modes. A5. According to the tension adjustment command, drive the tension adjustment device to adjust the tension of the nonwoven fabric in the longitudinal and / or transverse directions.

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