A control method and control system for a two-for-one twisting machine

Abstract

The application relates to a control method and a control system of a two-for-one twister, the control method comprising the following steps: continuously acquiring multiple images at a yarn area to obtain a reference image group, the images in the reference images being sequentially arranged in a time sequence; extracting a yarn object included in the images and determining a contour feature of the yarn object; determining a positioning reference in the reference images; determining a swing frequency of the yarn object according to the contour feature of the yarn object; determining a yarn tension change according to the swing frequency of the yarn object; and adjusting the yarn tension according to the swing frequency, wherein the adjusting of the yarn tension comprises any one of adjusting a tensioner, adjusting a winding speed and adjusting a spindle rotating speed. The control method and the control system of the two-for-one twister disclosed by the application can determine the yarn tension in a non-contact detection mode, can avoid yarn abrasion while ensuring the stability of production parameters, and are helpful to improving product quality.

Description

Technical Field

[0001] This application relates to the field of mechanical automation control technology, and in particular to a control method and control system for a twisting machine. Background Technology

[0002] Yarn count is an important indicator for measuring the fineness of yarn. The higher the count, the finer the yarn. With the increasing demand for lighter, softer, and more upscale textile products, high-count yarns (usually referring to yarns with a count of 50 or higher) are being used more and more widely in the textile industry.

[0003] The main problems encountered in the twisting process of high-count yarns are: because high-count yarns have fewer fibers in their cross-section, the cohesion between fibers needs to overcome greater tension during twisting, which makes the yarn very prone to breakage when subjected to tension during twisting and winding. The high breakage rate not only reduces production efficiency but also increases the difficulty of subsequent processes. In the twisting triangle area, the edge fibers are poorly controlled and tend to form long and numerous fuzz, which can even cause the fibers to scatter and deteriorate the yarn evenness.

[0004] From a testing perspective, the main problem with contact testing is the continuous sliding friction between the detection element and the surface of the high-speed running yarn. This external force can easily cause the fibers on the yarn surface to be pulled out, resulting in pilling and, in severe cases, the risk of single yarn breakage. High-count yarns are fine and soft, and when the contact probe applies measurement pressure, the yarn cross-section undergoes significant compressive elastic deformation. This deformation can lead to a systematic underestimation of the measured yarn diameter or linear density data, thus introducing fundamental errors. Summary of the Invention

[0005] This application provides a control method and control system for a doubling machine, which determines yarn tension through non-contact detection. This ensures stable production parameters while preventing yarn wear and helps improve product quality.

[0006] The above-mentioned objective of this application is achieved through the following technical solution: In a first aspect, this application provides a control method for a doubling twister, comprising: Multiple images are continuously acquired in the area where the yarn is located to obtain a reference image group, and the images in the reference image are set sequentially in time series; Extract yarn objects from the image and determine the contour features of the yarn objects; Identify the localization reference in the reference image; the localization reference is the same in each image of the reference image group. The oscillation frequency of the yarn object is determined based on its contour characteristics; Determine the yarn tension change based on the oscillation frequency of the yarn object; Adjusting yarn tension according to the oscillation frequency includes adjusting the tensioner, adjusting the winding speed, and adjusting the spindle speed.

[0007] In one possible implementation of the first aspect, when acquiring multiple images consecutively in the area where the yarn is located, it further includes: When an image is obtained, its location number is determined and its sharpness is calculated. When the image clarity meets the requirements, the image is filled into the image sequence according to the image position number. The image sequence includes multiple positions, each position corresponds to a position number, and one position number corresponds to multiple images. When all positions in the image sequence are filled, the images in the image sequence are used as a reference image group and the positions in the image sequence are cleared. Once a position in the image sequence is filled, the image corresponding to the position number will not be acquired in this round. If there are unfilled positions in the image sequence after the set shooting frequency, the positions in the image sequence will be cleared.

[0008] In one possible implementation of the first aspect, the number of times the positions in the image sequence are cleared due to unfilled positions is counted, and an alarm signal is issued when the number is greater than or equal to a set number.

[0009] In one possible implementation of the first aspect, extracting the yarn objects included in the image includes: In the image, identify the associated objects that have a physical relationship with the yarn object and the locations of the associated objects, wherein the number of locations is at least two; Determine the potential location area of ​​the yarn object based on the location of the associated object; Determine the center line of the potential location area and create filter lines based on the center line. The filter lines are perpendicular to the center line, and adjacent filter lines are set parallel to each other. Analyze the pixels on the screening line to determine the pixels that belong to the yarn object; The pixels belonging to the yarn object are sorted according to the positions of the corresponding filter lines to obtain the yarn object.

[0010] In one possible implementation of the first aspect, analyzing the pixels on the screening line and determining the pixels belonging to the yarn object includes: An analysis curve is built using the pixels on the filter line, with the position of the pixel as the horizontal axis and the pixel value as the vertical axis. The analysis curve is segmented to obtain background segments and non-background segments; Calculate the average gray value of the pixels belonging to the background segment and use the average gray value as the background gray value; Calculate the difference between each pixel belonging to the non-background segment and the mean gray value of the background to obtain a difference array; The difference array is filtered using a dynamic value. Differences less than or equal to the dynamic value are discarded, resulting in a remaining difference array. The differences in the remaining difference array are arranged consecutively, and the number of remaining difference arrays is one. The pixels corresponding to the remaining difference array are assigned to the yarn object.

[0011] In one possible implementation of the first aspect, segmenting the analysis curve includes: The analysis curve is traversed, and the average pixel value at each traversal position is calculated. The distribution of pixel values ​​in the statistical analysis curve is used to select the most frequent pixel value as the reference value for the pixel mean. Generate deviation intervals based on pixel mean reference values; The pixels whose pixel values ​​on the analysis curve are outside the reference range are taken as the non-background segment, and the remaining pixels are taken as the background segment.

[0012] In one possible implementation of the first aspect, determining the dynamic value includes: Calculate the standard deviation of pixels belonging to the background segment; The dynamic value is calculated based on the standard deviation. The dynamic value = standard deviation * confidence coefficient. The confidence coefficient is positively correlated with the light intensity.

[0013] Secondly, this application provides a control device for a doubling twister, comprising: The image acquisition unit is used to continuously acquire multiple images in the area where the yarn is located to obtain a reference image group, in which the images are set sequentially in time series. The image extraction unit is used to extract yarn objects included in the image and determine the contour features of the yarn objects; The reference extraction unit is used to determine the localization reference in the reference image. The localization reference is the same in each image of the reference image group. The frequency analysis unit is used to determine the oscillation frequency of the yarn object based on its contour characteristics. Tension analysis unit, used to determine yarn tension changes based on the oscillation frequency of the yarn object; The adjustment unit is used to adjust the yarn tension according to the oscillation frequency. Adjusting the yarn tension includes adjusting the tensioner, adjusting the winding speed, and adjusting the spindle speed.

[0014] Thirdly, this application provides a control system for a doubling twister, the system comprising: One or more memories are used to store instructions; One or more processors are configured to call and execute the instructions from the memory to perform the methods described in the first aspect and any possible implementation thereof.

[0015] Fourthly, this application provides a computer-readable storage medium, the computer-readable storage medium comprising: The program, when run by a processor, is executed as described in the first aspect and any possible implementation thereof.

[0016] Fifthly, this application provides a computer program product, including program instructions that, when run by a computing device, execute the method described in the first aspect and any possible implementation thereof.

[0017] Sixthly, this application provides a chip system including a processor for implementing the functions involved in the foregoing aspects, such as generating, receiving, transmitting, or processing the data and / or information involved in the foregoing methods.

[0018] This chip system can consist of chips or include chips and other discrete components.

[0019] In one possible design, the chip system also includes a memory for storing necessary program instructions and data. The processor and the memory can be decoupled and located on different devices, connected via wired or wireless means, or the processor and the memory can be coupled to the same device. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the steps of a control method for a doubling machine provided in this application.

[0021] Figure 2 This is a structural schematic diagram of a doubling twister provided in this application.

[0022] Figure 3 This is a partially enlarged schematic diagram of a twisting machine provided in this application.

[0023] Figure 4 This is a schematic diagram of a filled image sequence provided in this application.

[0024] Figure 5 This is a schematic diagram illustrating the division of the yarn's swing range as provided in this application.

[0025] Figure 6 This is a schematic diagram of the processing of a certain position in an image sequence after being filled, as provided in this application.

[0026] Figure 7 This is a schematic diagram illustrating the processing of a certain position in another image sequence provided in this application after it has been filled.

[0027] Figure 8 This is a schematic diagram of a potential location area provided in this application.

[0028] Figure 9 This is a schematic diagram of creating a filter line provided in this application.

[0029] Figure 10 This is a schematic diagram of a fitting process using the pixels of a yarn object, as provided in this application.

[0030] Figure 11 This is a schematic diagram illustrating the division of background and non-background segments provided in this application. Detailed Implementation

[0031] The technical solutions in this application will be further described in detail below with reference to the accompanying drawings.

[0032] This application discloses a control method for a doubling twister. Please refer to [link / reference]. Figure 1 In some examples, the control method for the doubling twister disclosed in this application includes the following steps: S101, acquire multiple images continuously in the area where the yarn is located to obtain a reference image group, and set the images in the reference image in a time series. S102, Extract the yarn objects included in the image and determine the contour features of the yarn objects; S103, Determine the positioning reference in the reference image, where the positioning reference is the same in each image of the reference image group; S104, Determine the oscillation frequency of the yarn object based on the contour characteristics of the yarn object; S105, determine the yarn tension change based on the oscillation frequency of the yarn object; S106, adjust the yarn tension according to the oscillation frequency. Adjusting the yarn tension includes adjusting the tensioner, adjusting the winding speed, and adjusting the spindle speed.

[0033] To better understand the technical solutions in this application, the relevant content will be introduced first.

[0034] The precise definition of twist is the number of twists per unit length of yarn. The most commonly used unit of measurement is TPM (Turns Per Meter), which is the number of twists per meter.

[0035] Modern doubling machines employ a constant linear speed winding mode to ensure stable yarn twist and uniform tension. This means that no matter how large the bobbin is wound, the absolute speed (linear speed, unit: meters per minute) at which the yarn is pulled out and wound onto the bobbin remains constant.

[0036] The twisting process is mainly handled by the spindle, winding shaft, and guide wire. It can be summarized as follows: the spindle rotates to twist, the winding shaft controls the linear speed, and the guide wire is responsible for the winding position. Constant linear speed winding is used in this process. The diameter of the bobbin on the winding shaft gradually increases, and the rotational speed (RPM) of the winding motor gradually decreases. During this process, the rotational speed of the spindle also gradually decreases.

[0037] If the tension is unstable during the twisting process, the following problems may occur: Chrysanthemum core and protruding edge: When the tension is too low, the yarn accumulates and loosens at both ends of the bobbin, forming a protruding "waistband" or "chrysanthemum core". This causes the yarn layers to interlock during subsequent unwinding, resulting in layer disorder and loop breakage. Hard edges and spider webs: When the tension is too high and changes abruptly, sharp hard edges will appear on the surface of the cylinder, which greatly increases the probability of breakage during subsequent warping. In severe cases, it may even cause the entire cylinder to burst due to excessive internal stress. Elastic fatigue and decreased elongation: Under repeated excessive stretching, the fibers in the yarn undergo plastic slippage, leading to a loss of yarn elasticity. This damage is irreversible; the strength may pass the test, but a large number of fibers will break during the weaving process. During the doubling or twisting process, unstable tension will cause the tension of the two yarns to be different, resulting in one strand being pulled thin and the other strand looping, which is very easy to cause breakage. Uneven dyeing: Areas with high density have greater resistance to dye penetration and less dye adheres, while areas with low density have faster dye penetration and more dye adheres, resulting in uneven fabric color. This defect is generally unacceptable for high-count (medium to high-end) fabrics.

[0038] The structure of a doubling twister is as follows Figure 2 and Figure 3 As shown, the yarn guide 101 moves horizontally to guide the yarn to wind onto the bobbin 102 of the winding shaft. The yarn used in this process is wound onto another bobbin, which is placed on the spindle rotor 103.

[0039] The control system disclosed in this application includes an image sensor and an image processing server. The image sensor is responsible for acquiring yarn images and then sending them back to the image processing server for processing. The results are then fed back to the control system of the twisting machine.

[0040] Based on the above content and the description in the background art, this application proposes the following solution: First, in step S101, multiple images are continuously acquired in the area where the yarn is located using an image sensor to obtain a reference image group. The images in the reference image are set sequentially in time series, that is, the area where the yarn is located is continuously image acquired in the time dimension.

[0041] Next, in step S102, the yarn objects included in the image are extracted and the contour features of the yarn objects are determined. This step can obtain the yarn objects. Then, in step S103, the positioning reference in the reference image is determined. Here, the positioning reference on each image in the reference image group needs to be the same.

[0042] The purpose of the positioning reference is to provide a positional reference for the yarn in the image. It should be understood that the technical solution of this application uses the yarn oscillation frequency to determine the yarn tension. The specific principle is to regard a segment of yarn between two points in motion as a taut string. Under certain conditions, the vibration frequency of this "string" (or the velocity of the transverse wave formed by the oscillation) has a definite mathematical relationship with the tension it experiences. The mathematical relationship is as follows: The tension T is proportional to the square of the vibration frequency f, and the formula is: T = 4μL 2 f 2 ; Where L is the yarn span, the free length between two points of the yarn, usually referring to the distance between two support points or clamping points; μ is the linear density, the mass per unit length (kg / m), which is determined based on the measured parameters of the twisted yarn.

[0043] In this application, the yarn oscillation frequency is determined by single-point analysis, that is, by analyzing the vibration frequency of the position points on the yarn as the yarn vibration frequency. However, since the yarn is in a moving state, it is necessary to detect the yarn position at different locations. At this time, multiple position points can be obtained. These position points are at different distances from the baseline provided by the positioning reference. By fitting these points, a curve can be obtained, and the frequency of this curve is the yarn vibration frequency.

[0044] Next, in step S104, the oscillation frequency of the yarn object is determined based on the contour features of the yarn object. Specifically, a position point is selected at a uniform height position on the contour features of multiple yarn objects. The distance (minimum straight-line distance) between the first position point and the positioning baseline provided by the positioning reference is S1, the distance (minimum straight-line distance) between the second position point and the positioning baseline provided by the positioning reference is S2, and so on.

[0045] Each location point has a time reference (as the horizontal axis) and a distance reference (as the vertical axis). These discrete points can be fitted to obtain a curve, and the frequency of this curve is the vibration frequency of the yarn.

[0046] In step S105, the yarn tension change is determined based on the oscillation frequency of the yarn object. Here, the actual yarn tension T can be calculated based on the aforementioned content. actual Then, the actual tension T of the yarn actual With respect to the required tension T of the yarn target By comparing the two, the actual tension of the yarn can be obtained. Tactual Is it too big or too small?

[0047] Δ T =T actual -T target ; If ΔT>0, it indicates that the actual tension of the yarn is too high; If ΔT < 0, it indicates that the actual tension of the yarn is too low; If ΔT=0 (or within the allowable error range), it means that the actual yarn tension meets the process requirements and no adjustment is needed.

[0048] Finally, in step S106, the yarn tension is adjusted according to the oscillation frequency. Adjusting the yarn tension includes adjusting the tensioner, adjusting the winding speed, and adjusting the spindle speed. Specifically: When the judgment result of step S105 is that the actual yarn tension is too high (ΔT>0), the control unit sends a command to the tensioner to reduce the tension, driving the actuator of the tensioner (such as a displacement adjustment motor, spring adjustment mechanism, etc.) to act, reducing the clamping force or frictional resistance of the tensioner on the yarn, so that the yarn tension decreases; when the judgment result of step S105 is that the actual yarn tension is too low (ΔT<0), the control unit sends a command to the tensioner to increase the tension, driving the actuator of the tensioner to act, increasing the clamping force or frictional resistance of the tensioner on the yarn, so that the yarn tension increases.

[0049] When the judgment result of step S105 is that the actual yarn tension is too high (ΔT>0), the control unit sends a speed reduction command to the winding drive motor to reduce the winding speed through the frequency converter or servo driver, thereby reducing the yarn tension; when the judgment result of step S105 is that the actual yarn tension is too low (ΔT<0), the control unit sends a speed increase command to the winding drive motor to increase the winding speed, thereby increasing the yarn tension.

[0050] When the judgment result of step S105 is that the actual yarn tension is too high (ΔT>0), the control unit sends a speed reduction command to the spindle drive motor to reduce the spindle speed through the frequency converter and reduce the yarn tension; when the judgment result of step S105 is that the actual yarn tension is too low (ΔT<0), the control unit sends a speed increase command to the spindle drive motor to increase the spindle speed and increase the yarn tension.

[0051] Preferably, a PID control algorithm can be used, with the tension deviation value ΔT as the input of the PID controller. After proportional, integral, and derivative operations, the output control quantity drives the tensioner actuator to make precise adjustments.

[0052] The magnitude of the tension deviation value ΔT determines the magnitude of the tensioner adjustment.

[0053] In some cases, when acquiring multiple images consecutively in the area where the yarn is located, the following method is used: S201, When the image is obtained, determine the image's location number and calculate the image's sharpness; S202, when the image clarity meets the requirements, the image is filled into the image sequence according to the image position number. The image sequence includes multiple positions, each position corresponds to a position number, and one position number corresponds to multiple images. When all positions in the image sequence are filled, the images in the image sequence are used as a reference image group and the positions in the image sequence are cleared. Once a position in the image sequence is filled, the image corresponding to the position number will not be acquired in this round. If there are unfilled positions in the image sequence after the set shooting frequency, the positions in the image sequence will be cleared.

[0054] It should be noted that this application requires the use of a high-speed image sensor for image capture. The core challenge here is the generation of massive amounts of data, which presents data transmission bottlenecks and real-time processing issues. To address this, this application employs an image sequence padding scheme. The number of positions in the image sequence is fixed, with one image placed at each position. Each image sequence is used as a set of analysis images, such as... Figure 4 As shown.

[0055] Specifically, such as Figure 5 As shown, it is assumed that the yarn moves from bottom to top and swings horizontally. The swing range is a fixed range. Then the swing range of the yarn can be divided. Each swing range corresponds to a position in the image sequence. The divided swing range is a known quantity.

[0056] The recommended angle for each zone is between 1° and 3°.

[0057] For images captured within a certain swing range, only one image is selected and included in the image sequence; all other images captured within that swing range are discarded. The specific rule is as follows: When an image is obtained, its position number is determined and its sharpness is calculated. If the sharpness meets the requirements, the image is filled into the image sequence according to its position number. If the sharpness does not meet the requirements, it is discarded. After the positions in the image sequence are filled, the high-speed image sensor continues to capture images (discarding them directly) or stops capturing images, such as... Figure 6 and Figure 7 As shown, this is only limited to the swing range (division) corresponding to the position in the image sequence, and the same process continues in the next swing range.

[0058] When there are unfilled positions in an image sequence after a set shooting frequency, the positions in the image sequence will be cleared. This is because the images stored in the image sequence have time-sensitive properties. If images with excessively long acquisition intervals are used for analysis, the results will not meet the time-sensitive requirements.

[0059] The image's position number is determined by the wire guide's position. For example, in the actual production process, the wire guide's position is calculated by the matching encoder. Here, the value fed back by the encoder can be used as the image's position number, meaning the image's position number is a spatial position number.

[0060] In some possible implementations, an image is assigned to the previous swing range when its spatial location falls exactly at the boundary between two swing ranges.

[0061] It should be noted that in this application, the physical storage structure of the image sequence is organized according to the spatial position number fed back by the wire guide encoder, in order to achieve efficient classification and caching of image data.

[0062] However, when performing frequency analysis later, the system does not rely on this storage order. Instead, it extracts the timestamp information of each frame of image and reorders all valid sampling points according to time sequence to construct a standard displacement-time series.

[0063] Through the decoupling strategy of spatial storage and temporal analysis described above, this application, while utilizing encoder data for convenient data management, strictly ensures the physical correctness of frequency extraction, providing accurate time and frequency parameters for subsequent calculation of tension using the string vibration equation.

[0064] In some cases, the system counts the number of times positions in the image sequence are cleared due to missing spaces. When the count exceeds or equals a set number, an alarm signal is issued, indicating a possible fault: Data acquisition failure: wire guide encoder malfunction, high-speed camera frame loss, and persistently substandard image clarity; Abnormal physical conditions: The yarn swing amplitude decreases sharply, making it unable to cover the preset spatial partition; or the yarn breaks or stops, resulting in no images available for acquisition.

[0065] If this clearing process only occurs once in a short period of time, it may just be a momentary environmental disturbance, and the system can recover on its own. However, if it occurs frequently in a short period of time (reaching the set number of times), it means that the occasional disturbance has evolved into a continuous systemic failure. Therefore, an alarm must be triggered, and manual intervention must be required for troubleshooting.

[0066] In some examples, the yarn objects included in the image are extracted in the following way: S301, determine in the image the associated object and the position of the associated object that have a physical relationship with the yarn object, wherein the number of the positions is at least two; S302, determine the potential location area of ​​the yarn object based on the location of the associated object; S303, determine the location center line of the potential location area and create filter lines based on the location center line. The filter lines are perpendicular to the location center line and adjacent filter lines are set in parallel. S304, Analyze the pixels on the screening line to determine the pixels belonging to the yarn object; S305, the obtained pixels belonging to the yarn object are sorted according to the position of the corresponding filter line to obtain the yarn object.

[0067] In steps S301 to S305, as follows Figure 5 and Figure 8 As shown, the yarn objects in the image are extracted based on their potential location regions. This is because if edge operators are used directly for extraction, the entire image would need to be processed. However, by using the potential location regions of the yarn objects, the processing range can be significantly reduced, which is more advantageous in terms of data processing volume and speed.

[0068] In actual production, the yarn position is only associated with the yarn guide and the bobbin of the winding shaft. The yarn guide is responsible for guiding the yarn onto the bobbin of the winding shaft. Therefore, determining the yarn guide and the bobbin can determine the potential position area of ​​the yarn.

[0069] Furthermore, since electronic cam technology is currently used, the yarn tilt angle is also a known quantity. This means that the potential location area of ​​the yarn can be accurately determined by the tilt angle of the yarn guide, the winding bobbin, and the yarn. Here, we assume that the maximum swing amplitude of the yarn is A. Considering the acquisition error factor, we expand the maximum swing amplitude of the yarn to 2A. Then we can obtain a rectangular area with a width of 4A and a length that is the actual length between the yarn guide and the winding bobbin (considering the yarn tilt angle). This rectangular area is the potential location area of ​​the yarn.

[0070] A more rigorous representation is as follows: Instantaneous position of the wire guide: Pg=(xg,yg), where xg is obtained by the encoder and yg is a fixed value (wire guide height); The position of the winding point on the surface of the cylinder is: Pb=(xb,yb), where xb is calculated from the winding diameter and yb is a fixed value (center height of the cylinder). The theoretical straight path of yarn: the straight line segment determined by two points, Pg and Pb; Instantaneous horizontal oscillation amplitude of the yarn: A (maximum value known); Axial projected length between the guide wire and the bobbin: L; The four boundaries of the ROI rectangular region are: X-axis lower limit: min(xg,xb)−A; Upper limit of the X-axis: max(xg,xb)+A; Y-axis lower limit: min(yg,yb)−A×tan(θ); Upper limit of Y-axis: max(yg,yb)+A×tan(θ); Where θ is the inclination angle of the yarn relative to the vertical direction, given by the electronic cam trajectory.

[0071] Next, in step S303, the center line of the potential location area is determined and a screening line is created based on the center line. The center line of the potential location area is obtained by connecting the center point of the guide yarn and the position point of the yarn on the bobbin (as previously stated). Specifically, these two points are connected by a line segment to obtain the center line of the potential location area.

[0072] Next, create filter lines, such as... Figure 9 As shown, the filter lines are perpendicular to the center line of the position, and adjacent filter lines are set parallel to each other. Then, the pixels on the filter lines are analyzed to determine the pixels belonging to the yarn object. Finally, the pixels belonging to the yarn object are arranged according to the positions of the corresponding filter lines to obtain the yarn object.

[0073] To further elaborate on the preceding description, when calculating image sharpness, only the sharpness of the areas used in the image needs to be calculated, since the areas used in each image are fixed, and the sharpness of these areas only needs to meet the requirements. Similarly, filter lines should be created only on the areas used in each image, rather than along the entire center line, as shown below. Figure 9 The area shown by the dashed line is as follows.

[0074] Because the traverse trajectory of the yarn guide is periodic, the projected position of the potential path of the yarn in the image also repeats periodically when the winding speed remains constant. Therefore, the location of the area of ​​use can be predetermined by the process parameters and remains unchanged during production.

[0075] The spacing d between adjacent filter lines is 2-5 pixels.

[0076] The reason for using the filter line is that the fixed height mentioned above may be missing or unclear in actual image analysis. However, the actual position of the fixed height can be calculated by using the pixels belonging to the yarn object on the filter line.

[0077] The specific method involves fitting the data using pixels belonging to the yarn object from multiple filtering lines, such as... Figure 10 As shown, a curve segment is obtained at this point. Then, by taking a point on this curve segment at a fixed height, the position point at the fixed height can be obtained, and the distance between this position point and the center line can be calculated.

[0078] In some examples, the pixels on the filter line are analyzed and the pixels belonging to the yarn object are determined in the following way: An analysis curve is built using the pixels on the filter line, with the position of the pixel as the horizontal axis and the pixel value as the vertical axis. The analysis curve is segmented to obtain background segments and non-background segments; Calculate the average gray value of the pixels belonging to the background segment and use the average gray value as the background gray value; Calculate the difference between each pixel belonging to the non-background segment and the mean gray value of the background to obtain a difference array; The difference array is filtered using a dynamic value. Differences less than or equal to the dynamic value are discarded, resulting in a remaining difference array. The differences in the remaining difference array are arranged consecutively, and the number of remaining difference arrays is one. The pixels corresponding to the remaining difference array are assigned to the yarn object.

[0079] This method requires first dividing the analysis curve into a background segment and a non-background segment. Here, the non-background segment corresponds to the yarn, and the background segment corresponds to the working environment. This is because the yarn and the working environment have a clear color difference. The yarn is usually opaque (appearing as a black shadow), and its gray value is much lower than that of the background air. Subtracting the gray value of the yarn from the background, the larger the value, the darker the area, and the higher the probability that it is the main body of the yarn.

[0080] The purpose of requiring continuity is to ensure that the remaining pixels are spatially adjacent, thus eliminating isolated noise. The purpose of requiring a quantity of one is to enforce that only one segment on this line can be identified as a yarn, and it can only be one yarn, because one yarn is the actual situation.

[0081] The dynamic value is determined as follows: Calculate the standard deviation of pixels belonging to the background segment; The dynamic value is calculated based on the standard deviation. The dynamic value = standard deviation * confidence coefficient. The confidence coefficient is positively correlated with the light intensity and is usually taken as 1.5-3.0.

[0082] The reason why the confidence coefficient is positively correlated with the light intensity is that more noise is generated when the light intensity is high, that is, background noise. Therefore, the greater the background noise, the higher the screening threshold must be, and the confidence coefficient needs to be appropriately increased. Here, a lookup table method is generally used, that is, the light intensity value and the confidence coefficient are directly correlated through the lookup table.

[0083] In the actual processing, the light intensity is obtained through sensors, and then the confidence coefficient is determined by querying.

[0084] In some examples, the specific methods for segmenting the analysis curve are as follows: The analysis curve is traversed, and the average pixel value at each traversal position is calculated. The distribution of pixel values ​​in the statistical analysis curve is used to select the most frequent pixel value as the reference value for the pixel mean. Generate deviation intervals based on pixel mean reference values; The pixels whose pixel values ​​on the analysis curve are outside the reference range are taken as the non-background segment, and the remaining pixels are taken as the background segment.

[0085] Traversing the pixels on the analysis curve and calculating the average pixel value at each traversal point means traversing the pixels on the analysis curve, taking the neighboring pixels (8 surrounding pixels) as the center of the traversal point, and calculating the average gray value of the pixels in that neighborhood as the smooth gray value at that position. The purpose of this method is to combat noise.

[0086] The statistical analysis of the pixel value distribution curve uses the pixel value with the highest number as the reference value for the pixel mean. This means that the pixel value with the highest number is used as the background pixel value. This is because the screening line is perpendicular to the yarn direction. On a screening line, the number of pixels belonging to the yarn body usually only accounts for 10%-30% of the total number of pixels, while the remaining 70%-90% is background air.

[0087] The deviation from the reference range is generated based on the pixel mean reference value because the pixel mean reference value is selected statistically in this method. This is because the background pixels are not strictly consistent (there is sensor noise and slight dust), and they fluctuate around a certain central value (mean or mode).

[0088] If you use a single point (reference value) to measure, many real background pixels will be misjudged as yarn due to slight fluctuations. However, if you use a line (range), you can encompass the entire background distribution.

[0089] At the same time, it is necessary to take into account the presence of interference (feathers, fly hairs). The gray values ​​of feathers and fly hairs are usually only slightly deviated from the background (the difference is not large). They are often located near the reference value, but at the edge of the interval.

[0090] By setting a reasonable tolerance range, signals with minor deviations (hair, fly) can be classified as background or discarded directly. Only when the pixel value deviates significantly from the range (i.e., after the low-confidence signal is removed, only the high-confidence signal remains) is it judged as the yarn body.

[0091] The deviation from the reference range is generally ±5-20 of the average pixel reference value.

[0092] This application also provides a control device for a doubling twister, including: The image acquisition unit is used to continuously acquire multiple images in the area where the yarn is located to obtain a reference image group, in which the images are set sequentially in time series. The image extraction unit is used to extract yarn objects included in the image and determine the contour features of the yarn objects; The reference extraction unit is used to determine the localization reference in the reference image. The localization reference is the same in each image of the reference image group. The frequency analysis unit is used to determine the oscillation frequency of the yarn object based on its contour characteristics. Tension analysis unit, used to determine yarn tension changes based on the oscillation frequency of the yarn object; The adjustment unit is used to adjust the yarn tension according to the oscillation frequency. Adjusting the yarn tension includes adjusting the tensioner, adjusting the winding speed, and adjusting the spindle speed.

[0093] Furthermore, when acquiring multiple images consecutively in the area where the yarn is located, it also includes: When an image is obtained, its location number is determined and its sharpness is calculated. When the image clarity meets the requirements, the image is filled into the image sequence according to the image position number. The image sequence includes multiple positions, each position corresponds to a position number, and one position number corresponds to multiple images. When all positions in the image sequence are filled, the images in the image sequence are used as a reference image group and the positions in the image sequence are cleared. Once a position in the image sequence is filled, the image corresponding to the position number will not be acquired in this round. If there are unfilled positions in the image sequence after the set shooting frequency, the positions in the image sequence will be cleared.

[0094] Furthermore, the number of times the positions in the image sequence are cleared due to unfilled positions is counted, and an alarm signal is issued when the number of times is greater than or equal to a set number.

[0095] Furthermore, the yarn objects extracted from the image include: In the image, identify the associated objects that have a physical relationship with the yarn object and the locations of the associated objects, wherein the number of locations is at least two; Determine the potential location area of ​​the yarn object based on the location of the associated object; Determine the center line of the potential location area and create filter lines based on the center line. The filter lines are perpendicular to the center line, and adjacent filter lines are set parallel to each other. Analyze the pixels on the screening line to determine the pixels that belong to the yarn object; The pixels belonging to the yarn object are sorted according to the positions of the corresponding filter lines to obtain the yarn object.

[0096] Furthermore, the analysis of pixels on the screening line and the determination of pixels belonging to the yarn object include: An analysis curve is built using the pixels on the filter line, with the position of the pixel as the horizontal axis and the pixel value as the vertical axis. The analysis curve is segmented to obtain background segments and non-background segments; Calculate the average gray value of the pixels belonging to the background segment and use the average gray value as the background gray value; Calculate the difference between each pixel belonging to the non-background segment and the mean gray value of the background to obtain a difference array; The difference array is filtered using a dynamic value. Differences less than or equal to the dynamic value are discarded, resulting in a remaining difference array. The differences in the remaining difference array are arranged consecutively, and the number of remaining difference arrays is one. The pixels corresponding to the remaining difference array are assigned to the yarn object.

[0097] Furthermore, segmenting the analysis curve includes: The analysis curve is traversed, and the average pixel value at each traversal position is calculated. The distribution of pixel values ​​in the statistical analysis curve is used to select the most frequent pixel value as the reference value for the pixel mean. Generate deviation intervals based on pixel mean reference values; The pixels whose pixel values ​​on the analysis curve are outside the reference range are taken as the non-background segment, and the remaining pixels are taken as the background segment.

[0098] Furthermore, determining the dynamic values ​​includes: Calculate the standard deviation of pixels belonging to the background segment; The dynamic value is calculated based on the standard deviation. The dynamic value = standard deviation * confidence coefficient. The confidence coefficient is positively correlated with the light intensity.

[0099] In one example, the unit in any of the above devices may be one or more integrated circuits configured to implement the above methods, such as one or more application-specific integrated circuits (ASICs), or one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs), or a combination of at least two of these integrated circuit forms.

[0100] For example, when the units in the device can be implemented through a processing element scheduler, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processor capable of calling programs. Alternatively, these units can be integrated together to form a system-on-a-chip (SOC).

[0101] In this application, various objects such as messages / information / devices / network elements / systems / apparatus / actions / operations / processes / concepts may be named. It is understood that these specific names do not constitute a limitation on the relevant objects. The names may be changed depending on the scenario, context, or usage habits. The understanding of the technical meaning of the technical terms in this application should be mainly determined from their functions and technical effects embodied / performed in the technical solution.

[0102] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0103] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0104] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0105] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0106] It should also be understood that in the various embodiments of this application, the terms "first," "second," etc., are merely to indicate that multiple objects are different. For example, a first time window and a second time window are only to indicate different time windows. They should not have any effect on the time windows themselves, and the aforementioned terms "first," "second," etc., should not impose any limitations on the embodiments of this application.

[0107] It should also be understood that, in the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced by each other, and the technical features in different embodiments can be combined to form new embodiments according to their inherent logical relationships.

[0108] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a computer-readable storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned computer-readable storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0109] This application also provides a control system for a doubling twister, the system comprising: One or more memories are used to store instructions; One or more processors are configured to retrieve and execute the instructions from the memory, performing the methods described above.

[0110] This application also provides a computer program product including instructions that, when executed, cause the terminal device and the network device to perform operations corresponding to the methods described above.

[0111] This application also provides a chip system including a processor for implementing the functions involved in the above description, such as generating, receiving, transmitting, or processing the data and / or information involved in the above methods.

[0112] This chip system can consist of chips or include chips and other discrete components.

[0113] The processor mentioned above can be a CPU, a microprocessor, an ASIC, or one or more integrated circuits that execute a program to control the method of transmitting the feedback information described above.

[0114] In one possible design, the chip system also includes a memory for storing necessary program instructions and data. The processor and the memory can be decoupled and located on different devices, connected via wired or wireless means to support the chip system in implementing the various functions described in the above embodiments. Alternatively, the processor and the memory can also be coupled to the same device.

[0115] Optionally, the computer instructions are stored in memory.

[0116] Optionally, the memory can be a storage unit within the chip, such as a register or cache. Alternatively, the memory can be a storage unit located outside the chip within the terminal, such as a ROM or other types of static storage devices that can store static information and instructions, such as RAM.

[0117] It is understood that the memory in this application may be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory.

[0118] Non-volatile memory can be ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory.

[0119] Volatile memory can be RAM, which is used as an external cache. There are many different types of RAM, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), and direct memory bus random access memory.

[0120] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A control method for a doubling twister, characterized in that, include: Multiple images are continuously acquired in the area where the yarn is located to obtain a reference image group, and the images in the reference image are set sequentially in time series; Extract yarn objects from the image and determine the contour features of the yarn objects; Identify the localization reference in the reference image; the localization reference is the same in each image of the reference image group. The oscillation frequency of the yarn object is determined based on its contour characteristics; Determine the yarn tension change based on the oscillation frequency of the yarn object; Adjusting yarn tension according to the oscillation frequency includes adjusting the tensioner, adjusting the winding speed, and adjusting the spindle speed.

2. The control method for a doubling twister according to claim 1, characterized in that, When acquiring multiple images consecutively in the area where the yarn is located, the following is also included: When an image is obtained, its location number is determined and its sharpness is calculated. When the image clarity meets the requirements, the image is filled into the image sequence according to the image position number. The image sequence includes multiple positions, each position corresponds to a position number, and one position number corresponds to multiple images. When all positions in the image sequence are filled, the images in the image sequence are used as a reference image group and the positions in the image sequence are cleared. Once a position in the image sequence is filled, the image corresponding to the position number will not be acquired in this round. If there are unfilled positions in the image sequence after the set shooting frequency, the positions in the image sequence will be cleared.

3. The control method for the doubling twister according to claim 2, characterized in that, The system counts the number of times positions in the image sequence are cleared due to unfilled positions. When the count is greater than or equal to a set number, an alarm signal is issued.

4. The control method for a doubling twister according to claim 1, characterized in that, The yarn objects extracted from the image include: In the image, identify the associated objects that have a physical relationship with the yarn object and the locations of the associated objects, wherein the number of locations is at least two; Determine the potential location area of ​​the yarn object based on the location of the associated object; Determine the center line of the potential location area and create filter lines based on the center line. The filter lines are perpendicular to the center line, and adjacent filter lines are set parallel to each other. Analyze the pixels on the screening line to determine the pixels that belong to the yarn object; The pixels belonging to the yarn object are sorted according to the positions of the corresponding filter lines to obtain the yarn object.

5. The control method for a doubling twister according to claim 4, characterized in that, Analyzing the pixels on the screening line and determining which pixels belong to the yarn object includes: An analysis curve is built using the pixels on the filter line, with the position of the pixel as the horizontal axis and the pixel value as the vertical axis. The analysis curve is segmented to obtain background segments and non-background segments; Calculate the average gray value of the pixels belonging to the background segment and use the average gray value as the background gray value; Calculate the difference between each pixel belonging to the non-background segment and the mean gray value of the background to obtain a difference array; The difference array is filtered using a dynamic value. Differences less than or equal to the dynamic value are discarded, resulting in a remaining difference array. The differences in the remaining difference array are arranged consecutively, and the number of remaining difference arrays is one. The pixels corresponding to the remaining difference array are assigned to the yarn object.

6. The control method for a doubling twister according to claim 5, characterized in that, Segmenting the analysis curve includes: The analysis curve is traversed, and the average pixel value at each traversal position is calculated. The distribution of pixel values ​​in the statistical analysis curve is used to select the most frequent pixel value as the reference value for the pixel mean. Generate deviation intervals based on pixel mean reference values; The pixels whose pixel values ​​on the analysis curve are outside the reference range are taken as the non-background segment, and the remaining pixels are taken as the background segment.

7. The control method for a doubling twister according to claim 5, characterized in that, Determining dynamic values ​​includes: Calculate the standard deviation of pixels belonging to the background segment; The dynamic value is calculated based on the standard deviation. The dynamic value = standard deviation * confidence coefficient. The confidence coefficient is positively correlated with the light intensity.

8. A control device for a doubling twister, characterized in that, include: The image acquisition unit is used to continuously acquire multiple images in the area where the yarn is located to obtain a reference image group, in which the images are set sequentially in time series. The image extraction unit is used to extract yarn objects included in the image and determine the contour features of the yarn objects; The reference extraction unit is used to determine the localization reference in the reference image. The localization reference is the same in each image of the reference image group. The frequency analysis unit is used to determine the oscillation frequency of the yarn object based on its contour characteristics. Tension analysis unit, used to determine yarn tension changes based on the oscillation frequency of the yarn object; The adjustment unit is used to adjust the yarn tension according to the oscillation frequency. Adjusting the yarn tension includes adjusting the tensioner, adjusting the winding speed, and adjusting the spindle speed.

9. A control system for a doubling twister, characterized in that, The system includes: One or more memories are used to store instructions; One or more processors are configured to retrieve and execute the instructions from the memory to perform the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes: The program, when run by the processor, executes the method as described in any one of claims 1 to 7.

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