A tracking and positioning system for a heat seal bar of a flexible material bag making machine

Abstract

The present application relates to the technical field of mechanical control, and particularly relates to a tracking positioning system of a heat sealing knife of a flexible material bag making machine, which comprises: an image acquisition unit, which is used for acquiring an image of a target area; an image processing unit, which is used for pre-processing the image and performing feature point comparison on the pre-processed image according to a feature point comparison algorithm to generate image deviation data of the image; an industrial computer, which is used for generating a deviation value corresponding to each heat sealing knife according to a control target value of each heat sealing knife and the image deviation data; a PLC control unit, which is used for generating a control instruction of each heat sealing knife according to a PID control algorithm and the deviation value; and a motion control unit, which is used for driving the heat sealing knife to move according to the control instruction. The beneficial effect is that the pattern position is detected in real time, and the heat sealing knife pressing position is adjusted according to the pattern position, so that the overlap of each heat sealing knife is realized, the yield in industrial production is increased, and the waste of raw materials is reduced.

Description

Technical Field

[0001] This invention relates to the field of mechanical control technology, and in particular to a tracking and positioning system for the heat sealing knife of a flexible material bag making machine. Background Technology

[0002] The process requirements of flexible material bag making machines, whether for three-side seal or center-seal bags, necessitate multiple heat sealing presses by horizontal and vertical heat sealing blades to complete the bag's shape. The same heat seal seam is pressed by different heat sealing blades at different times, but the position of each heat sealing blade's indentation relative to the pattern must be consistent. Current bag making machine heat sealing blade systems typically have three or more sets of heat sealing blades. In addition to temperature control, these systems also include manual horizontal positioning. This means that, based on different bag types and patterns, the horizontal heat sealing blades are manually moved to the designed heat seal seam, and each heat sealing blade maintains a strictly consistent distance from the pattern (without stretching), thus achieving overlapping heat seal seams.

[0003] The aforementioned hot stamping structure, when the printed pattern doesn't change much and the material doesn't stretch much after hot stamping, allows us to assume that the required hot stamping position remains essentially unchanged. The hot stamping blade is manually moved to determine the position, which generally meets the above requirements. However, in actual production, flexible materials undergo printing, lamination, and curing processes before bag making. Due to variations in tension and temperature, the length of the printed pattern itself changes. Furthermore, during bag making, the flexible material is continuously hot-pressed in the heated environment of the hot stamping blade, and the bag-making machine constantly cycles between traction and stopping, causing significant tension fluctuations. When the material pattern passes through the hot stamping blade, the pattern length changes considerably, especially for heat-sensitive, easily stretched thin materials, such as single-material PE film, where the problem is more pronounced.

[0004] A fixed-position heat-sealing method results in constantly changing relative positions between the heat-sealed seam and the pattern. The seams from the front and rear heat-sealing blades cannot overlap and are constantly moving relative to each other, affecting product quality and causing significant material waste. Therefore, there is an urgent need for a method that can detect the pattern position in real time and adjust the heat-sealing blade's position accordingly, ensuring that the heat-sealing blade tracks the pattern in real time, and guaranteeing that the relative position of the heat-sealed seam and the pattern changes even when the pattern moves forward or backward. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a tracking and positioning system for the heat sealing knife of a flexible material bag making machine, which solves the technical problems of material waste caused by the continuous change of the heat sealing position when the heat sealing knife is moved manually and the inability of the heat sealing seams of the front and rear heat sealing knives to overlap, as well as the waste of human resources caused by non-automated production.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0009] This invention provides a tracking and positioning system for the heat sealing knife of a flexible material bag making machine, including a frame, an image acquisition unit, an image processing unit, an industrial control computer, a PLC control unit, and N heat sealing components, where N is a natural number that is not zero;

[0010] N heat sealing assemblies are supported on the frame and arranged sequentially from the feed end to the discharge end of the frame; each heat sealing assembly includes a heat sealing blade and a motion control unit for controlling the operation of the heat sealing blade;

[0011] The image acquisition unit is used to acquire images of a pre-defined target area;

[0012] The image processing unit is used to preprocess the image acquired by the image acquisition unit, and compare the preprocessed image with a pre-set reference image according to a pre-set feature point comparison algorithm to generate image deviation data of the image.

[0013] The industrial control computer is used to generate a deviation value corresponding to each heat sealing knife based on the control target value of each heat sealing knife and the image deviation data; the control target value is the control parameter corresponding to each heat sealing knife generated by the industrial control computer when it first receives the image deviation data.

[0014] The PLC control unit is used to generate a control command for the heat sealing knife corresponding to each deviation value according to the pre-set PID control algorithm and each deviation value, and send the control command to the motion control unit corresponding to the heat sealing knife.

[0015] Each of the motion control units is used to drive its corresponding heat sealing knife to a designated position according to the received control command.

[0016] Optionally, the image acquisition unit includes N cameras; one camera is arranged between each of two adjacent heat-sealing components arranged in sequence, and an additional camera is arranged on the side of the last heat-sealing component where no camera is arranged; each camera is used to acquire an image of its pre-set target area, and one camera corresponds to one hot air component.

[0017] Optionally, the image processing unit preprocesses all images acquired by the camera and compares all preprocessed images with a pre-set reference image based on a pre-set feature point comparison algorithm to generate image deviation data for all images.

[0018] The industrial control computer directly uses the image deviation data as the deviation value of the heat sealing knife corresponding to the image deviation data.

[0019] Optionally, the image acquisition unit includes N+1 cameras; one camera is set between each of two adjacent heat-sealing components arranged in sequence, and an additional camera is set on the side of the first and last cameras where no camera is set;

[0020] The image processing unit is used to preprocess the image acquired by the image acquisition unit, and compare the preprocessed image with a pre-set reference image according to a pre-set feature point comparison algorithm to generate image deviation data of the image, including:

[0021] After receiving images from all cameras simultaneously, the image processing unit preprocesses all images and compares the preprocessed images with a pre-set reference image based on a pre-set feature point comparison algorithm to generate image deviation data for each image.

[0022] Optionally, the PLC control unit is configured to generate a control command for the heat sealing knife corresponding to each deviation value based on a pre-set PID control algorithm and each deviation value, and send the control command to the motion control unit corresponding to the heat sealing knife, including:

[0023] The PLC control unit processes the deviation value corresponding to each heat sealing knife according to the pre-set PID control algorithm, and generates control output data corresponding to each heat sealing knife.

[0024] The PLC control unit generates a control command for each heat sealing knife based on the preset number of pulses per unit length and the control output data corresponding to each heat sealing knife, and sends each control command to the motion control unit corresponding to the control command; the control command is a correction pulse that drives the motion control unit to control the heat sealing knife.

[0025] The PID control algorithm is as follows:

[0026] ;

[0027] Among them, K p K is a proportionality constant. o K is the integration constant. d e is the differential constant. i (k) represents the deviation value of the kth acquisition of the i-th heat sealing knife set sequentially, e i (k-1) represents the deviation value collected in the (k-1)th time for the i-th heat sealing knife set sequentially. u is the sum of the deviation values ​​from the first acquisition to the kth acquisition of the i-th heat sealing knife set sequentially.i (k) represents the control output data collected k times for the i-th heat sealing knife, which is set sequentially.

[0028] Optionally, the PLC control unit is also used to modify each of the control commands according to the axis compensation parameters preset for each heat sealing knife.

[0029] Optionally, the industrial control computer is also used to generate a control target value corresponding to each heat sealing knife according to a pre-set formula and all image deviation data when it receives image deviation data for the first time.

[0030] Formula 1 is:

[0031] ;

[0032] Among them, K i d is the control target value set sequentially for the i-th heat sealing knife. i For the image deviation data acquired for the first time by the i-th camera set sequentially, d i+1 L is the image deviation data acquired for the first time by the (i+1)th camera in a sequential setup. i L is the distance from the i-th camera to the center of the i-th heat sealing blade, set sequentially. i+1 This is the distance from the (i+1)th camera to the center of the ith heat sealing blade, set sequentially.

[0033] Optionally, the industrial control computer is used to generate a deviation value corresponding to each heat sealing knife based on the control target value of each heat sealing knife and the image deviation data, including:

[0034] The industrial control computer calculates the deviation value corresponding to each heat sealing knife based on the pre-set formula 2, all image deviation data, and the control target value corresponding to each heat sealing knife.

[0035] Formula 2 is as follows:

[0036] ;

[0037] Among them, e i (k) represents the deviation value of the kth acquisition of the i-th heat sealing knife set sequentially, d i (k) represents the image deviation data corresponding to the k-th acquisition by the i-th camera set sequentially, d i+1 (k) represents the image deviation data corresponding to the k-th acquisition of the (i+1)-th camera, set sequentially. i L is the distance from the i-th camera to the center of the i-th heat sealing blade, set sequentially. i+1 K is the distance from the (i+1)th camera to the center of the ith heat sealing blade, set sequentially. i The control target value is set sequentially for the i-th heat sealing knife.

[0038] Optionally, after the image processing unit performs noise reduction and binarization on the image, it draws the ROI region of the processed image and performs feature extraction to generate a feature image of the ROI region.

[0039] The feature image is compared with a pre-set reference image based on a pre-set feature point comparison algorithm, and image deviation data is generated by a pre-set script.

[0040] Optionally, the image acquisition unit further includes a light source corresponding to each camera;

[0041] Any of the light sources is used to illuminate the area captured by its corresponding camera;

[0042] All of the light sources described herein are elongated strip light sources.

[0043] (III) Beneficial Effects

[0044] The beneficial effects of the present invention are: the tracking and positioning system of the heat sealing knife of the flexible material bag making machine of the present invention, by adopting automated real-time adjustment of the position of the heat sealing knife, can achieve overlapping of the heat sealing seams of the front and rear heat sealing knives, reducing the waste of human resources and raw materials compared with the prior art. Attached Figure Description

[0045] Figure 1 This is a system block diagram of the tracking and positioning system for the heat sealing knife of a bag making machine according to Embodiment 1 of the present invention;

[0046] Figure 2 This is a schematic diagram of the camera and light source according to Embodiment 2 of the present invention;

[0047] Figure 3 This is a schematic diagram of the structure of the heat-sealing assembly, camera, and light source according to Embodiment 2 of the present invention;

[0048] Figure 4 This is a schematic diagram of the bag-making machine structure according to Embodiment 3 of the present invention;

[0049] Figure 5 This is a simplified diagram of the industrial control computer calculation principle according to Embodiment 3 of the present invention;

[0050] Figure 6 This is a schematic diagram of the ROI region feature image according to Embodiment 1 or Embodiment 3 of the present invention. Detailed Implementation

[0051] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0052] The present invention proposes a tracking and positioning system for the heat sealing knife of a flexible material bag making machine. By adopting automated real-time adjustment of the heat sealing knife position, it can achieve overlapping of the heat sealing seams of the front and rear heat sealing knives, reducing the waste of human resources and raw materials compared with the prior art.

[0053] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0054] Example 1

[0055] This invention provides a tracking and positioning system for the heat sealing knife of a flexible material bag making machine, such as... Figure 1 As shown, it includes:

[0056] The system consists of a frame, an image acquisition unit, an image processing unit, an industrial computer, a PLC control unit, and N heat-sealing components, where N is a non-zero natural number.

[0057] N heat sealing assemblies are supported on the frame and arranged sequentially from the feed end to the discharge end of the frame. Each heat sealing assembly includes a heat sealing knife and a motion control unit for controlling the operation of the heat sealing knife. Generally, the motion control unit is a motor and driver that drives the heat sealing knife to move, and one motion control unit drives one heat sealing knife to work.

[0058] The image acquisition unit is used to acquire images of a pre-defined area, which is typically the area where each heat sealing knife will work, including multiple areas.

[0059] The image processing unit preprocesses the images acquired by the image acquisition unit. Preprocessing includes operations such as image denoising, binarization, ROI region segmentation, and feature point extraction to generate ROI region feature images, such as... Figure 6 As shown; then, the preprocessed image is compared with the pre-set reference image by feature points according to the pre-set feature point comparison algorithm to generate image deviation data.

[0060] An industrial control computer, or industrial control computer, has a pre-set deviation value calculation algorithm to generate the corresponding deviation value for each heat sealing knife based on the control target value and image deviation data for each heat sealing knife.

[0061] The PLC control unit is used to generate control commands for each heat sealing knife according to the pre-set PID control algorithm and deviation value, and send them to the corresponding motion control unit.

[0062] Any motion control unit is used to drive its corresponding heat sealing knife to a designated position according to the received control command.

[0063] The system also includes equipment for a conventional bag-making machine, including a traction drive structure. When the traction drive stops, the image acquisition unit begins to acquire images until the PLC generates control commands and sends them to the motion control unit. When the bag-making machine pulls again, the motion control unit is required to move the heat-sealing knife to improve work efficiency.

[0064] The present invention proposes a tracking and positioning system for the heat sealing knife of a flexible material bag making machine. By adopting automated real-time adjustment of the heat sealing knife position, it can achieve overlapping of the heat sealing seams of the front and rear heat sealing knives, reducing the waste of human resources and raw materials compared with the prior art.

[0065] Example 2

[0066] This invention provides a tracking and positioning system for the heat sealing knife of a flexible material bag making machine, comprising:

[0067] The system consists of a frame, an image processing unit, an industrial computer, a PLC control unit, N heat-sealing components, and N cameras, where N is a non-zero natural number.

[0068] Each camera serves as an image acquisition unit, used to acquire images of a pre-defined target area. One camera is positioned between each pair of adjacent heat-sealing components, with an additional camera positioned on the side of the last heat-sealing component that does not currently have a camera. Each camera is used to acquire images of its pre-defined target area, and one camera corresponds to one hot air component. The image acquisition unit typically also includes a light source for illuminating the camera's acquisition position, with each light source corresponding to one camera. Both the camera and the light source are mounted on a camera mount. Figure 2 As shown; generally, the camera bracket and the heat sealing knife are connected by a connecting structure, with both the camera and the light source located on one side of the heat sealing knife, such as... Figure 3 As shown, the image captured by the camera corresponds to the heat sealing knife.

[0069] At this time, the image processing unit preprocesses the images acquired by all cameras and compares the feature points of all preprocessed images with the pre-set reference images according to the pre-set feature point comparison algorithm to generate image deviation data for all the images; while the industrial control computer directly uses the image deviation data as the deviation value of the corresponding heat sealing knife.

[0070] The PLC control unit is used to generate the control program corresponding to each heat sealing knife according to the pre-set PID control algorithm and deviation value, and send it to the corresponding motion control unit.

[0071] Any motion control unit is used to drive its corresponding heat sealing knife to a designated position according to the received control command.

[0072] The present invention proposes a tracking and positioning system for the heat sealing knife of a flexible material bag making machine. By adopting automated real-time adjustment of the heat sealing knife position, it can achieve overlapping of the heat sealing seams of the front and rear heat sealing knives compared with the prior art, reducing the waste of human resources and raw materials. Moreover, the image deviation data corresponding to each heat sealing knife obtained by the image processing unit is directly used as the deviation value of the heat sealing knife, and the process is simple.

[0073] Example 3

[0074] This invention provides a tracking and positioning system for the heat sealing knife of a flexible material bag making machine, comprising:

[0075] The system consists of a frame, an image processing unit, an industrial computer, a PLC control unit, N heat-sealing components, and N+1 cameras, where N is a non-zero natural number.

[0076] N+1 cameras serve as image acquisition units, used to acquire images of a pre-defined target area. One camera is positioned between each of two adjacent heat-sealing components arranged sequentially, and an additional camera is positioned on the side of the first and last cameras where no camera is currently installed. Figure 4 As shown.

[0077] The image processing unit performs noise reduction and binarization on each image, then draws the Region of Interest (ROI) of the processed image, extracts features, and generates a feature image of the ROI region, such as... Figure 6 As shown, each feature image is compared with a pre-set reference image based on a pre-set feature point comparison algorithm, and image deviation data is generated by a pre-set script.

[0078] When the industrial control computer first receives image deviation data, it generates the control target value corresponding to each heat sealing knife based on the pre-set formula one and all image deviation data. Upon receiving subsequent image deviation data, it calculates the deviation value corresponding to each heat sealing knife based on the pre-set formula two, all image deviation data, and the control target value corresponding to each heat sealing knife, such as... Figure 5 As shown.

[0079] Formula 1 is:

[0080] ;

[0081] Among them, K i d is the control target value set sequentially for the i-th heat sealing knife. i For the image deviation data acquired for the first time by the i-th camera set sequentially, d i+1L is the image deviation data acquired for the first time by the (i+1)th camera in a sequential setup. i L is the distance from the i-th camera to the center of the i-th heat sealing blade, set sequentially. i+1 This is the distance from the (i+1)th camera to the center of the ith heat sealing blade, set sequentially.

[0082] Formula 2 is:

[0083] ;

[0084] Among them, e i (k) represents the deviation value of the kth acquisition of the i-th heat sealing knife set sequentially, d i (k) represents the image deviation data corresponding to the k-th acquisition by the i-th camera set sequentially, d i+1 (k) represents the image deviation data corresponding to the k-th acquisition of the (i+1)-th camera, set sequentially. i L is the distance from the i-th camera to the center of the i-th heat sealing blade, set sequentially. i+1 K is the distance from the (i+1)th camera to the center of the ith heat sealing blade, set sequentially. i The control target value is set sequentially for the i-th heat sealing knife.

[0085] The PLC control unit processes the deviation value corresponding to each heat sealing knife according to a pre-set PID control algorithm, and generates control output data corresponding to each heat sealing knife; and generates control command corresponding to each heat sealing knife according to a pre-set number of pulses per unit length and the control output data corresponding to each heat sealing knife, and sends each control command to the motion control unit corresponding to the control command; the control command is a correction pulse that drives the motion control unit to control the operation of the heat sealing knife.

[0086] The PID control algorithm is as follows:

[0087] ;

[0088] Among them, K p K is a proportionality constant. o K is the integration constant. d e is the differential constant. i (k) represents the deviation value of the kth acquisition of the i-th heat sealing knife set sequentially, e i (k-1) represents the deviation value collected in the (k-1)th time for the i-th heat sealing knife set sequentially. u is the sum of the deviation values ​​from the first acquisition to the kth acquisition of the i-th heat sealing knife set sequentially. i (k) represents the control output data collected k times for the i-th heat sealing knife, which is set sequentially.

[0089] The motion control unit is used to drive its corresponding heat sealing knife to a designated position according to the received control command.

[0090] The present invention proposes a tracking and positioning system for the heat sealing knife of a flexible material bag making machine. By adopting automated real-time adjustment of the heat sealing knife position, it can achieve overlapping of the heat sealing seams of the front and rear heat sealing knives compared with the prior art, reducing the waste of human resources and raw materials. Furthermore, by calculating the deviation value of a heat sealing knife through the image deviation data obtained from the front and rear cameras, the positioning of the heat sealing knife is more accurate.

[0091] Example 4

[0092] This invention provides a tracking and positioning method for the horizontal sealing knife of a bag making machine, comprising:

[0093] The heat sealing blades include: horizontal sealing blades and vertical sealing blades; all the horizontal sealing blades are supported on the frame and are arranged sequentially from the feed end of the frame to the discharge end of the frame.

[0094] Each horizontal sealing knife is equipped with a camera imaging device, which includes a camera and a light source.

[0095] When the bag-making machine stops, the feature pattern of the material is captured. After noise reduction, the color image is binarized into a grayscale image. The ROI (Region of Interest) and feature point regions are drawn. The image data of the ROI region is obtained through feature extraction, Gaussian filtering, image enhancement and other methods. The position of the feature pattern captured each time is calculated by writing a script in C#.

[0096] Similarly, after the other camera patterns are processed in the same way, the position data of the feature patterns near each horizontal sealing knife are obtained, that is, the image deviation data.

[0097] The deviation value of the corresponding horizontal sealing knife is directly used based on the image deviation data.

[0098] In addition to installing a camera imaging device on each horizontal sealing knife, an extra camera imaging device is installed on the first horizontal sealing knife.

[0099] The image deviation data for each camera image is calculated using the same process described above.

[0100] The deviation value of a horizontal sealing knife is calculated using the image deviation data from two cameras. For example, the deviation value of the first horizontal sealing knife, which is set sequentially, is calculated using the first camera and the second camera on both sides of the first horizontal sealing knife.

[0101] The image deviation data initially acquired by the first and second cameras are d respectively. 10 and d 20Let L1 be the distance from the center of the first camera to the center of the first horizontal sealing knife; let L2 be the distance from the second camera to the center of the first horizontal sealing knife. Then the axial spacing is L1 + L2; the distance between the two patterns under the two cameras is d. 10 +d 20 +L1+L2; The control target value for the first horizontal sealing blade is:

[0102] ;

[0103] The image deviation data from the second capture by the first and second cameras are denoted as d. 11 and d 21 Then the deviation value of the first horizontal sealing knife is:

[0104] e=K*(d 11 +L1+d 21 +L2)-d 11 -L1;

[0105] After obtaining the deviation value e, it is digitally filtered and then processed using the PID control algorithm formula.

[0106] ;

[0107] The control output data for this calculation is obtained. This data is multiplied by the number of pulses per unit length to obtain the correction pulse count for the motor driving the horizontal sealing knife. This control then drives the motor to complete the position positioning action, achieving the goal of the horizontal sealing knife following the pattern changes. Wherein, K... p K is a proportionality constant. o K is the integration constant. d is a differential constant.

[0108] In addition, each horizontal sealing knife is equipped with axis compensation parameters to eliminate systematic errors in the process and modify the pressing position according to the actual situation to ensure tracking effect.

[0109] This embodiment provides a method for detecting the position of multiple horizontal sealing knives using a combination of multiple cameras, and presents a complete detection and control scheme, including calculating image deviation using feature image recognition, the relationship between image deviations of adjacent horizontal sealing knives, deviation control algorithms, and control methods for actuators. The control entities in the implementation include, but are not limited to, industrial control computers, PLCs, ARMs, FPGAs, etc.

[0110] The present invention proposes a tracking and positioning system for the horizontal sealing knife of a bag making machine. By adopting automated real-time adjustment of the horizontal sealing knife position, it can achieve overlapping of the hot seams of the front and rear hot knives compared with the prior art, reducing the waste of human resources and raw materials. Furthermore, by calculating the deviation value of a horizontal sealing knife through the image deviation data obtained from the front and rear cameras, the positioning of the horizontal sealing knife is more accurate.

[0111] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0112] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0113] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Furthermore, "above," "over," or "on top" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," or "beneath" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0114] In the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0115] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A tracking and positioning system for the heat sealing knife of a flexible material bag making machine, characterized in that, It includes a frame, an image acquisition unit, an image processing unit, an industrial computer, a PLC control unit, and N heat-sealing components, where N is a non-zero natural number; N heat sealing assemblies are supported on the frame and arranged sequentially from the feed end to the discharge end of the frame; each heat sealing assembly includes a heat sealing blade and a motion control unit for controlling the operation of the heat sealing blade; The image acquisition unit is used to acquire images of a pre-defined target area; The image processing unit is used to preprocess the image acquired by the image acquisition unit, and compare the preprocessed image with a pre-set reference image according to a pre-set feature point comparison algorithm to generate image deviation data of the image. The industrial control computer is used to generate a deviation value corresponding to each heat sealing knife based on the control target value of each heat sealing knife and the image deviation data; the control target value is the control parameter corresponding to each heat sealing knife generated by the industrial control computer when it first receives the image deviation data. The PLC control unit is used to generate a control command for the heat sealing knife corresponding to each deviation value according to the pre-set PID control algorithm and each deviation value, and send the control command to the motion control unit corresponding to the heat sealing knife. Any of the motion control units is used to drive its corresponding heat sealing knife to a designated position according to the received control command; The image acquisition unit includes N or N+1 cameras; When the image acquisition unit includes N+1 cameras, the industrial control computer is used to generate a deviation value corresponding to each heat sealing knife based on the control target value of each heat sealing knife and the image deviation data, including: Based on the pre-set Formula 2 and all image deviation data, as well as the control target value corresponding to each heat sealing knife, calculate the deviation value corresponding to each heat sealing knife; Formula 2 is as follows: ； Among them, e i (k) represents the deviation value of the kth acquisition of the i-th heat sealing knife set sequentially, d i (k) represents the image deviation data corresponding to the k-th acquisition by the i-th camera set sequentially, d i+1 (k) represents the image deviation data corresponding to the k-th acquisition of the (i+1)-th camera, set sequentially. i L is the distance from the i-th camera to the center of the i-th heat sealing blade, set sequentially. i+1 K is the distance from the (i+1)th camera to the center of the ith heat sealing blade, set sequentially. i The control target value is set sequentially for the i-th heat sealing knife.

2. The tracking and positioning system for the heat-sealing knife of the flexible material bag making machine according to claim 1, characterized in that, When the image acquisition unit includes N cameras, the image acquisition unit is configured as follows: one camera is set between each of two adjacent heat-sealing components arranged in sequence, and an additional camera is set on the side of the last heat-sealing component where no camera is set; each camera is used to acquire an image of its pre-set target area, and one camera corresponds to one heat-sealing component.

3. The tracking and positioning system for the heat-sealing knife of the flexible material bag making machine according to claim 2, characterized in that, When the image acquisition unit includes N cameras, the image processing unit is used to preprocess the images acquired by the image acquisition unit, and compare the preprocessed images with a pre-set reference image according to a pre-set feature point comparison algorithm to generate image deviation data of the images, including: The image processing unit preprocesses all images captured by the camera and compares all preprocessed images with a pre-set reference image based on a pre-set feature point comparison algorithm to generate image deviation data for all images. When the image acquisition unit includes N cameras, the industrial control computer is used to generate a deviation value corresponding to each heat sealing knife based on the control target value of each heat sealing knife and the image deviation data, including: The image deviation data is directly used as the deviation value of the heat sealing knife corresponding to the image deviation data.

4. The tracking and positioning system for the heat-sealing knife of the flexible material bag making machine according to claim 1, characterized in that, When the image acquisition unit includes N+1 cameras, the image acquisition unit is configured as follows: one camera is set between each of two adjacent heat-sealing components arranged in sequence, and an additional camera is set on the side of the first and last cameras where no camera is set. When the image acquisition unit includes N+1 cameras, the image processing unit is used to preprocess the images acquired by the image acquisition unit, and compare the preprocessed images with a pre-set reference image according to a pre-set feature point comparison algorithm to generate image deviation data of the images, including: After receiving images from all cameras simultaneously, the image processing unit preprocesses all images and compares the preprocessed images with a pre-set reference image based on a pre-set feature point comparison algorithm to generate image deviation data for each image.

5. The tracking and positioning system for the heat-sealing knife of the flexible material bag making machine according to claim 1, characterized in that, The PLC control unit is used to generate a control command for the heat sealing knife corresponding to each deviation value based on a pre-set PID control algorithm and each deviation value, and to send the control command to the motion control unit corresponding to the heat sealing knife, including: The PLC control unit processes the deviation value corresponding to each heat sealing knife according to the pre-set PID control algorithm, and generates control output data corresponding to each heat sealing knife. The PLC control unit generates a control command for each heat sealing knife based on the preset number of pulses per unit length and the control output data corresponding to each heat sealing knife, and sends each control command to the motion control unit corresponding to the control command; the control command is a correction pulse that drives the motion control unit to control the heat sealing knife. The PID control algorithm is as follows: ； Among them, K p K is a proportionality constant. o K is the integration constant. d e is the differential constant. i (k) represents the deviation value of the kth acquisition of the i-th heat sealing knife set sequentially, e i (k-1) represents the deviation value collected in the (k-1)th time for the i-th heat sealing knife set sequentially. u is the sum of the deviation values ​​from the first acquisition to the kth acquisition of the i-th heat sealing knife set sequentially. i (k) represents the control output data collected k times for the i-th heat sealing knife, which is set sequentially.

6. The tracking and positioning system for the heat-sealing knife of the flexible material bag making machine according to claim 1, characterized in that, The PLC control unit is also used to modify each of the control commands according to the axis compensation parameters preset for each heat sealing knife.

7. The tracking and positioning system for the heat-sealing knife of the flexible material bag making machine according to claim 4, characterized in that, The industrial control computer is also used to generate a control target value for each heat sealing knife based on a pre-set formula and all image deviation data when it first receives image deviation data. Formula 1 is: ； Among them, K i d is the control target value set sequentially for the i-th heat sealing knife. i For the image deviation data acquired for the first time by the i-th camera set sequentially, d i+1 L is the image deviation data acquired for the first time by the (i+1)th camera in a sequential setup. i L is the distance from the i-th camera to the center of the i-th heat sealing blade, set sequentially. i+1 This is the distance from the (i+1)th camera to the center of the ith heat sealing blade, set sequentially.

8. The tracking and positioning system for the heat-sealing knife of the flexible material bag making machine according to claim 1, characterized in that, The image processing unit is used to preprocess the image acquired by the image acquisition unit, and compare the preprocessed image with a pre-set reference image according to a pre-set feature point comparison algorithm to generate image deviation data of the image, including: After the image processing unit performs noise reduction and binarization on the image, it draws the ROI region of the processed image and performs feature extraction to generate a feature image of the ROI region. The feature image is compared with a pre-set reference image based on a pre-set feature point comparison algorithm, and image deviation data is generated by a pre-set script.

9. The tracking and positioning system for the heat-sealing knife of a flexible material bag-making machine according to claim 1, characterized in that, The image acquisition unit also includes a light source corresponding to each camera; Any of the light sources is used to illuminate the area captured by its corresponding camera; All of the light sources described herein are elongated strip light sources.

Images