A high-speed feedforward system and method for pole piece detection

Abstract

This application belongs to the field of industrial vision technology, and particularly relates to a high-speed feedforward system and method for pole piece detection. The high-speed feedforward method for pole piece detection in this application adjusts the diopter of the liquid telecentric lens according to the feedforward parameter information; obtains an end face image of the pole piece with better imaging resolution and imaging signal-to-noise ratio; and then completes the burr defect detection of the pole piece through a vision algorithm. Based on feedforward correction, this application has the advantages of fast response speed and effective avoidance of missed detection, and is suitable for high-speed motion scenarios; it is not limited by the inherent depth of field of the optical system, allows a larger aperture diaphragm, has great flexibility, and is conducive to obtaining better imaging resolution and imaging signal-to-noise ratio; the liquid telecentric lens has the advantages of fast response speed, good stability, small volume, and strong repeatability, making this application more suitable for high-speed detection application scenarios; the structure and algorithm of this application are relatively simple, which is conducive to obtaining the stability and accuracy of detection.

Description

Technical Field

[0001] The present application relates to the field of industrial vision technology, and particularly to a high-speed feedforward system and method for pole piece detection. Background Art

[0002] With the continuous development of the new energy industry, lithium battery technology has been widely used in many fields such as mobile phones, laptops, and driverless cars due to its advantages of high energy density, pollution-free, and long life. In the battery pole piece of a lithium battery: the upper and lower layers are carbon powder layers, and the middle is a metal layer. In the lithium battery manufacturing process, affected by the stability of processing equipment, there may be a situation where the burrs of the metal layer penetrate the carbon powder layer during the pole piece cutting process, which is likely to cause an internal short circuit of the battery and leave a major safety hazard for the use of the battery.

[0003] Therefore, pole piece burr detection is directly related to the safety and reliability of the battery. However, in the lithium battery pole piece burr detection technology, affected by the repeatability of actual process equipment, the end face position of the pole piece on the conveyor belt will fluctuate within a certain range and will not be stable at a fixed position. As a result, the end face of the pole piece will change rapidly in the depth of field direction, and it is difficult to clearly image the end face of the pole piece due to the limitation of the small inherent depth of field of the detection system based on microscopic imaging, which cannot meet the requirements of real-time industrial detection.

[0004] Currently, in the prior art, manual sampling inspection and the method of reducing the aperture diaphragm to expand the depth of field are generally used for pole piece burr detection. For the manual sampling inspection method, it is necessary to manually select some samples, place the samples under a professional microscope, manually focus and judge whether there are burr defects at each position one by one, with low efficiency; for the method of reducing the aperture diaphragm to expand the depth of field, on-line detection can be realized, but the range of expanding the depth of field by reducing the size of the aperture diaphragm is limited, and it cannot meet the requirement of clear imaging of the pole piece end face under large-range fluctuations. Therefore, the number of detections is limited. At the same time, since reducing the aperture diaphragm affects the light passing amount of the system, the imaging signal-to-noise ratio drops severely, which is not conducive to the accuracy of subsequent machine vision algorithms for detecting burr defects. Summary of the Invention

[0005] The present application provides a high-speed feedforward system and method for pole piece detection to solve the problems of low efficiency and insufficient accuracy in the existing lithium battery pole piece burr detection.

[0006] The technical solution adopted by the present application is as follows:

[0007] In the first aspect of the present application, a high-speed feedforward system for pole piece detection is provided, including a laser alignment instrument, a liquid telecentric lens, a high-speed area array camera, and a computer;

[0008] Among them, the laser alignment instrument is configured to: measure the relative position of the pole piece end face in the depth of field direction in real time and send a deviation detection signal;

[0009] The computer is configured to: receive the deviation detection signal and send a liquid lens control signal;

[0010] The liquid telecentric lens is configured to: receive the liquid lens control signal and adjust the diopter according to the liquid lens control signal to change the imaging object plane position;

[0011] The high-speed area array camera is configured to: perform image acquisition through the liquid telecentric lens to obtain an end face image of the pole piece;

[0012] The computer is further configured to: receive the end face image of the pole piece and detect burr defects of the pole piece through a vision algorithm.

[0013] In some embodiments, it further includes an annular LED array and a fill light controller, and the fill light controller controls the lighting on and off of the annular LED array according to the control signal of the laser alignment instrument.

[0014] In some embodiments, the computer is further configured to: receive the deviation detection signal and delay sending the liquid lens control signal processed by the correction algorithm.

[0015] In some embodiments, the correction algorithm is:

[0016]

[0017] Wherein, v (m / s) is the uniform motion speed of the conveyor belt, L (m) is the relative distance between the laser alignment instrument and the liquid telecentric lens in the conveyor belt movement direction, dx (m) is the relative distance between the laser alignment instrument and the liquid telecentric lens in the imaging depth of field direction, f (Hz) is the sampling frequency of the alignment instrument, x n (m) is the deviation output for the nth time, δt1 (s) is the communication system transmission delay, φ n (dpt) is the diopter of the liquid telecentric lens for the nth time, δt2 (s) is the liquid lens response delay, and K (m / dpt) is the working distance sensitivity of the liquid telecentric lens.

[0018] In a second aspect of the present application, a high-speed feedforward method for pole piece detection is provided, including the following steps:

[0019] Measure the relative position of the end face of the pole piece in the depth of field direction in real time and send a deviation detection signal;

[0020] Receive the deviation detection signal and send a liquid lens control signal;

[0021] Receive the liquid lens control signal and adjust the diopter of the liquid telecentric lens according to the liquid lens control signal to change the imaging object plane position;

[0022] Image acquisition is performed through the liquid telecentric lens to obtain an image of the end face of the pole piece;

[0023] Receive the image of the end face of the pole piece, and detect the burr defect of the pole piece through a vision algorithm.

[0024] In some embodiments, in the step of performing image acquisition through the liquid telecentric lens to obtain an image of the end face of the pole piece, it further includes:

[0025] Simultaneously turn on the annular LED array to illuminate the end face of the pole piece for supplementary lighting.

[0026] In some embodiments, in the step of receiving the deviation detection signal and sending a liquid lens control signal, it further includes:

[0027] Receive the deviation detection signal, and delay sending the liquid lens control signal processed by the correction algorithm.

[0028] In some embodiments, the delay calculates the delay amount of sending the liquid lens control signal according to the distance between the laser alignment instrument and the liquid telecentric lens, the moving speed of the conveyor belt, and the sampling frequency parameter information of the laser alignment instrument.

[0029] In some embodiments, in the step of receiving the deviation detection signal and delaying sending the liquid lens control signal processed by the correction algorithm, it further includes: pre-measuring and obtaining algorithm parameter information, and configuring the correction algorithm;

[0030] Wherein, the algorithm parameter information includes the uniform moving speed v (m / s) of the conveyor belt, the relative distance L (m) between the laser alignment instrument and the liquid telecentric lens in the moving direction of the conveyor belt, the relative distance dx (m) between the laser alignment instrument and the liquid telecentric lens in the imaging depth of field direction, the sampling frequency of the laser alignment instrument is f (Hz), the deviation output for the nth time is x n (m), the transmission delay of the communication system is δt1 (s), the diopter of the liquid lens for the nth time is Ф n (dpt), the response delay of the liquid lens is δt2 (s), and the working distance sensitivity of the entire liquid lens group is K (m / dpt);

[0031] The correction algorithm is:

[0032]

[0033] The beneficial effects of adopting the technical solution of the present application are as follows:

[0034] The high-speed feedforward system and method for pole piece detection of the present application have the following advantages:

[0035] 1) This application is based on feedforward correction. Compared with the negative feedback system based on the image defocus result, it has the advantages of fast response speed and effectively avoiding missed detection, and is particularly suitable for high-speed motion scenarios.

[0036] 2) Compared with the fixed large-depth-of-field detection system, this application can meet the imaging scenarios with arbitrarily changing depth of field, is not limited by the inherent depth of field of the optical system, and has great flexibility. At the same time, this application has good depth-of-field adaptability, realizes a large depth of field, allows a relatively large aperture diaphragm, which is beneficial to ensuring better imaging resolution and imaging signal-to-noise ratio.

[0037] 3) This application realizes object plane adjustment based on a liquid lens. Compared with traditional mechanical focusing, due to the advantages of fast response speed, good stability, small volume and strong repeatability of the liquid lens, this application is more suitable for the application scenarios of high-speed detection.

[0038] 4) This application is based on a liquid telecentric lens, and there is a good linear relationship between its control quantity (current) and the controlled quantity (object plane position). There is no need for complex non-linear correction methods, and the structure and algorithm are relatively simple, which is beneficial to obtaining the stability and accuracy of detection. Description of the Drawings

[0039] In order to more clearly illustrate the technical solutions of this application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0040] Figure 1 It is a schematic structural diagram of an embodiment of the first aspect of this application.

[0041] Figure 2 It is a flowchart of an embodiment of the second aspect of this application.

[0042] Reference Numerals: 100 - Laser Alignment Instrument, 200 - Liquid Telecentric Lens, 300 - High-Speed Area Array Camera, 400 - Computer, 500 - Ring LED Array. Detailed Embodiments

[0043] To make the purpose, implementation manner and advantages of this application clearer, the exemplary implementation manners of this application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of this application. Obviously, the described exemplary embodiments are only a part of the embodiments of this application, rather than all the embodiments.

[0044] It should be noted that the brief description of the terms in this application is only for the convenience of understanding the subsequent described implementation manners, rather than intending to limit the implementation manners of this application. Unless otherwise specified, these terms should be understood in their ordinary and common meanings.

[0045] In this application, terms such as "first", "second", "third", etc. in the description, claims and the above-mentioned drawings are used to distinguish similar or like objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise noted. It should be understood that such terms can be interchanged under appropriate circumstances.

[0046] The terms "comprising" and "having" and any variations thereof are intended to cover but not exclusively include. For example, a product or device comprising a series of components does not necessarily have to be limited to all the components clearly listed, but may include other components not clearly listed or inherent to these products or devices.

[0047] In order to achieve the detection of burrs on the lithium battery electrode sheet, currently, by adopting the method of reducing the aperture diaphragm to expand the depth of field, the electrode sheet with fluctuations in a certain depth-of-field direction can be clearly imaged, and then by means of machine vision, it is detected whether the metal layer of the electrode sheet penetrates the toner layer, so as to judge whether there are burr defects. Although this method can achieve online detection, the range of the depth of field expanded by reducing the size of the aperture diaphragm is limited, and it cannot meet the clear imaging of the electrode sheet end face fluctuating in a large range. Therefore, it cannot detect all samples, but only part of the samples can be detected, and reducing the aperture diaphragm will seriously affect the light throughput of the system and cause a serious decrease in the imaging signal-to-noise ratio, which is not conducive to the subsequent detection of burr defects by machine vision algorithms.

[0048] This application focuses on the future high-speed production and high-reliability requirements of lithium batteries, and strives to break through the existing technical solutions. It proposes a feedforward high-speed imaging solution based on a liquid lens, provides an effective solution for the high-speed large-depth-of-field detection of lithium battery electrode sheets, and provides strong support for the high-reliability and high-speed industrial production process of lithium batteries. Compared with the traditional detection scheme, it is necessary to add a laser alignment instrument to measure the relative position of the electrode sheet end face in the depth-of-field direction in real time, and feed the position obtained by real-time measurement back to the liquid lens. By quickly modulating the corresponding diopter of the liquid lens, the position of the imaging object plane of the optical system is changed to achieve clear imaging of the electrode sheet end face. Based on the clear imaging result, it is possible to quickly judge whether there are process defects such as burrs on the electrode sheet end face by using traditional machine vision detection algorithms or deep learning, etc.

[0049] For the convenience of understanding this application, the technical principles involved in this application are described as follows:

[0050] a) In existing industrial inspections, often due to the disturbance of the measured object plane by the shape of the sample itself or the conveying mechanism, the surface of the item to be imaged oscillates repeatedly in a certain space. This oscillation will cause the detection result of the industrial camera to be blurred, and this blur is because the object image plane exceeds the depth-of-field range of the lens itself, so clear imaging cannot be achieved;

[0051] b) The liquid lens is a new type of optical element composed of a special thin film and liquid. By changing the lens voltage or current signal, the surface shape of the lens will change, thereby changing the diopter (i.e., 1 / focal length). In a telecentric imaging system based on a liquid lens, by changing the control signal (voltage or current) of the liquid lens, the diopter can be changed, and finally the object plane of the imaging system can be changed;

[0052] c) The laser alignment instrument emits parallel-line lasers and is received by a line array camera. When an object blocks part of the line lasers, the relative position of the object end face can be quickly calculated through the signal of the line array camera. And this position is used as the relative offset of the object;

[0053] d) The laser alignment instrument can be used to quickly detect the offset of an object in the depth-of-field direction. By changing the control signal of the liquid lens, the plane position where the camera can clearly image can be changed. Therefore, in the industrial inspection of burrs on the end face of lithium electrode sheets, by detecting the offset position of the electrode sheet upstream and outputting the appropriate liquid lens control signal at the appropriate time, an image of the burr end face of the electrode sheet can be clearly captured by the camera. This avoids the problem that the traditional method cannot achieve clear imaging throughout the process due to the inherent depth-of-field limitation of the optical system. It provides important support for subsequent detection of defects such as lithium battery burrs based on machine vision or deep learning and other means.

[0054] The technical problem to be solved by this method is to avoid the low spatial resolution and low signal-to-noise ratio caused by the low light flux due to reducing the aperture diaphragm size in the traditional method, and at the same time, it can fundamentally solve the difficulties of machine vision detection in industrial scenarios with large depth-of-field and variable object planes, especially in high-speed industrial scenarios.

[0055] In the first aspect of this application, a high-speed feedforward system for electrode sheet detection is provided, including a laser alignment instrument 100, a liquid telecentric lens 200, a high-speed area array camera 300, and a computer 400;

[0056] Among them, the laser alignment instrument 100 is configured to: measure the relative position of the electrode sheet end face in the depth-of-field direction in real time and send a deviation detection signal;

[0057] The computer 400 is configured to: receive the deviation detection signal and send a liquid lens control signal;

[0058] The liquid telecentric lens 200 is configured to: receive the liquid lens control signal and adjust the diopter according to the liquid lens control signal to change the imaging object plane position;

[0059] The high-speed area array camera 300 is configured to: collect an image of the electrode sheet end face through the liquid telecentric lens 200;

[0060] The computer 400 is further configured to: receive the end face image of the pole piece and detect the burr defect of the pole piece through a vision algorithm.

[0061] See Figure 1 , in the above embodiments, in the burr detection of the cutting end face of the lithium battery pole piece, a feed-forward type dynamic adjustment imaging object plane is used to meet the imaging requirements of high speed and large depth of field, which provides a favorable support for subsequent detection of defects such as burrs on the pole piece by means of machine vision and the like. The laser alignment instrument 100 measures the relative coordinate position of the current sample cutting end face in the depth of field direction and generates a deviation detection signal, which is used to control the liquid telecentric lens 200 to perform diopter adjustment, so as to be conducive to obtaining an end face image of the pole piece with better imaging resolution and imaging signal-to-noise ratio under high speed and large depth of field, and further provides a good image basis for machine vision detection, ensuring the detection efficiency and quality in a high-speed moving scene.

[0062] In some embodiments, it further includes an annular LED array 500 and a fill light controller, and the fill light controller controls the light on and off of the annular LED array 500 according to the control signal of the laser alignment instrument 100.

[0063] Good lighting conditions provide strong support for the imaging shooting effect. By adjusting and controlling the fill light controller through the control signal of the laser alignment instrument 100, the light of the annular LED array 500 is turned on and off according to a preset time. On the one hand, it saves electric energy and has good economy; on the other hand, when the high-speed area array camera 300 takes a picture of the end face of the pole piece through the liquid telecentric lens 200, the object surface to be photographed is filled with light, which is conducive to obtaining a higher clarity imaging photo and indirectly improving the accuracy of defect detection.

[0064] In some embodiments, the computer 400 is further configured to: receive the deviation detection signal and delay the transmission of the liquid lens control signal processed by the correction algorithm.

[0065] Since the battery electrodes to be photographed follow the conveyor belt and present non-identical movement trajectories, there are certain spatial position differences in the imaging object plane of the electrodes. To obtain clear pictures with good shooting effects, it is necessary to adjust the diopter of the liquid telecentric lens 200 in real time. On the conveyor belt, there is a certain spatial distance between the laser alignment instrument 100 and the liquid telecentric lens 200. The battery electrode first passes through the laser alignment instrument 100, and the laser alignment instrument 100 measures the relative coordinate position of the battery electrode in the depth of field direction to generate a deviation detection signal. However, it still takes some time for the battery electrode to move to the shooting position of the liquid telecentric lens 200. To accurately photograph the imaging object plane of the battery electrode, it is necessary to delay the shooting of the liquid telecentric lens 200 so that the battery electrode is just photographed when it falls into the shooting position of the liquid telecentric lens 200. Delayed sending of the liquid lens control signal processed by the calibration algorithm is conducive to accurately obtaining the image of the electrode end face.

[0066] In some embodiments, the calibration algorithm is as follows:

[0067]

[0068] where v (m / s) is the uniform movement speed of the conveyor belt, L (m) is the relative distance between the laser alignment instrument 100 and the liquid telecentric lens 200 in the conveyor belt movement direction, dx (m) is the relative distance between the laser alignment instrument 100 and the liquid telecentric lens 200 in the imaging depth of field direction, f (Hz) is the sampling frequency of the alignment instrument, x n (m) is the deviation output for the nth time, δt1 (s) is the communication system transmission delay, φ n (dpt) is the diopter of the liquid telecentric lens 200 for the nth time, δt2 (s) is the liquid lens response delay, and K (m / dpt) is the working distance sensitivity of the liquid telecentric lens 200.

[0069] A relative coordinate system is established using the camera and the laser alignment instrument 100. By accurately calculating the delay parameters, and then outputting the real-time control quantity of the liquid telecentric lens 200 processed by the calibration algorithm after delay, the diopter of the liquid telecentric lens 200 is controlled to obtain better shooting parameters for the object surface of the battery electrode, which is conducive to the high-definition imaging effect of the camera. Therefore, the delay in this embodiment plays a very important role. However, in the actual application process, due to the production of each component and the error tolerance, the accurately calculated delay parameters do not exactly correspond to the values of the delay required for actual shooting during actual testing. This requires fine-tuning the delay parameters according to the actual situation to obtain the delay parameters required for accurate shooting.

[0070] Refer to Figure 2 , in the second aspect of the present application, a high-speed feedforward method for electrode detection is provided, including the following steps:

[0071] S101. Measure the relative position of the end face of the electrode plate in the depth of field direction in real time and send a deviation detection signal;

[0072] S102. Receive the deviation detection signal and send a liquid lens control signal;

[0073] S103. Receive the liquid lens control signal and adjust the diopter of the liquid telecentric lens according to the liquid lens control signal to change the position of the imaging object plane;

[0074] S104. Perform image acquisition through the liquid telecentric lens to obtain an image of the end face of the electrode plate;

[0075] S105. Receive the image of the end face of the electrode plate and detect the burr defect of the electrode plate through a vision algorithm.

[0076] In some embodiments, in the step of performing image acquisition through the liquid telecentric lens to obtain an image of the end face of the electrode plate, it further includes:

[0077] Simultaneously turn on the annular LED array to illuminate the end face of the electrode plate for supplementary lighting.

[0078] In some embodiments, in the step of receiving the deviation detection signal and sending a liquid lens control signal, it further includes:

[0079] Receive the deviation detection signal and delay sending the liquid lens control signal processed by the correction algorithm.

[0080] In some embodiments, the delay calculates the delay amount of sending the liquid lens control signal based on the distance between the laser alignment instrument and the liquid telecentric lens, the conveyor belt movement speed, and the sampling frequency parameter information of the laser alignment instrument.

[0081] In some embodiments, in the step of receiving the deviation detection signal and delaying sending the liquid lens control signal processed by the correction algorithm, it further includes: pre-measuring and obtaining algorithm parameter information and configuring the correction algorithm;

[0082] Wherein, the algorithm parameter information includes the conveyor belt uniform movement speed v (m / s), the relative distance L (m) between the laser alignment instrument and the liquid telecentric lens in the conveyor belt movement direction, the relative distance dx (m) between the laser alignment instrument and the liquid telecentric lens in the imaging depth of field direction, the sampling frequency of the laser alignment instrument is f (Hz), the deviation output for the nth time is x n (m), the communication system transmission delay is δt1 (s), the diopter of the liquid lens for the nth time is φ n (dpt), the liquid lens response delay is δt2 (s), and the working distance sensitivity of the entire liquid lens group is K (m / dpt);

[0083] The calibration algorithm is as follows:

[0084]

[0085] For the high-speed feedforward system and method for pole piece detection of the present application, due to being based on feedforward calibration, compared with the negative feedback system based on the image defocus result, it has the advantages of fast response speed and effectively avoiding missed detection, and is especially suitable for high-speed motion scenarios; compared with the fixed large-depth-of-field detection system, the present application can meet the imaging scenarios with arbitrarily varying depth of field, is not restricted by the inherent depth of field of the optical system, and has great flexibility; at the same time, the present application has good depth-of-field adaptability, realizes a large depth of field, allows a relatively large aperture diaphragm, which is beneficial to ensuring better imaging resolution and imaging signal-to-noise ratio; the present application realizes object plane adjustment based on a liquid lens. Compared with traditional mechanical focusing, due to the advantages of fast response speed, good stability, small volume and strong repeatability of the liquid lens, the present application is more suitable for the application scenarios of high-speed detection; the present application is based on a liquid telecentric lens, and there is a good linear relationship between its control quantity (current) and the controlled quantity (object plane position), without the need for complex non-linear calibration methods, and the structure and algorithm are relatively simple, which is beneficial to obtaining the stability and accuracy of detection.

[0086] The present application is mainly applied to the field of battery production detection, and to a certain extent solves the problem of high-speed real-time accurate detection of the end face of the pole piece under dynamic large depth of field. The system of the present application can be implemented in actual applications as follows: First, fix the laser alignment instrument, the liquid telecentric lens and the high-speed area array camera at the lithium battery pole piece station. Among them, the laser alignment instrument should be placed upstream of the liquid telecentric imaging lens and the high-speed area array camera. Second, the laser alignment instrument is turned on to measure the position of the end face of the lithium battery pole piece in the coordinate system of the laser alignment instrument at a fixed frequency. Then, a processing platform such as a computer receives the deviation detection signal, through an appropriate delay, and converts the relative coordinate position of the pole piece into the diopter control quantity of the liquid lens through the calibration algorithm. For the controlled liquid lens, its imaging object plane is modulated to the current end face position of the pole piece. Finally, the high-speed area array camera continuously and rapidly acquires images, and based on the clear imaging results, completes the detection of defects such as pole piece burrs through means such as machine vision. Of course, based on the clear captured images, in addition to detecting burrs, other defects can still be detected.

[0087] In some other embodiments, based on the concept of feedforward detection technology, a precision electric displacement stage can be used to replace the liquid lens in the present application for object plane adjustment. However, this alternative solution has the disadvantages of high cost, large volume and slow response speed. Compared with the foregoing embodiments, it is not very suitable for future high-speed industrial detection. However, the feedforward system using a precision electric displacement stage still belongs to the inventive concept of the present application.

[0088] For the similar parts between the embodiments provided in this application, reference can be made to each other. The specific embodiments provided above are only several examples under the general concept of this application and do not constitute a limitation on the protection scope of this application. For those skilled in the art, any other embodiments extended based on the solution of this application without creative efforts fall within the protection scope of this application.

Claims

1. A high-speed feedforward system for pole piece detection, characterized in that, It includes a laser alignment instrument, a liquid telecentric lens, a high-speed area array camera, and a computer; Among them, the laser alignment instrument is configured to: measure the relative position of the end face of the pole piece in the depth of field direction in real time and send a deviation detection signal; The computer is configured to: receive the deviation detection signal and send a liquid telecentric lens control signal; The liquid telecentric lens is configured to: receive the liquid telecentric lens control signal and adjust the diopter according to the liquid telecentric lens control signal to change the position of the imaging object plane; The high-speed area array camera is configured to: perform image acquisition through the liquid telecentric lens to obtain an image of the end face of the pole piece; The computer is further configured to: receive the image of the end face of the pole piece and detect the burr defect of the pole piece through a vision algorithm; The computer is further configured to: receive the deviation detection signal and delay the sending of the liquid telecentric lens control signal processed by the correction algorithm; The correction algorithm is: Among them, v is the uniform motion speed of the conveyor belt, with the unit of m / s; L is the relative distance between the laser alignment instrument and the liquid telecentric lens in the conveyor belt movement direction, with the unit of m; dx is the relative distance between the laser alignment instrument and the liquid telecentric lens in the imaging depth of field direction, with the unit of m; f is the sampling frequency of the alignment instrument, with the unit of Hz; x n is the deviation output for the nth time, with the unit of m; δt1 is the transmission delay of the communication system, with the unit of s; φ n is the diopter of the liquid telecentric lens for the nth time, with the unit of dpt; δt2 is the response delay of the liquid telecentric lens, with the unit of s; K is the working distance sensitivity of the liquid telecentric lens, with the unit of m / dpt.

2. The high-speed feedforward system for pole piece detection according to claim 1, wherein It further includes an annular LED array and a fill light controller, and the fill light controller controls the on / off of the light of the annular LED array according to the control signal of the laser alignment instrument.

3. A high-speed feedforward method for pole piece detection, which is applicable to the system described in any one of claims 1 to 2, characterized in that, It includes the following steps: Measure the relative position of the end face of the pole piece in the depth of field direction in real time and send a deviation detection signal; Receive the deviation detection signal and send a liquid telecentric lens control signal; Receive the liquid telecentric lens control signal and adjust the diopter of the liquid telecentric lens according to the liquid telecentric lens control signal to change the position of the imaging object plane; Perform image acquisition through the liquid telecentric lens to obtain an image of the end face of the pole piece; Receive the image of the end face of the pole piece and detect the burr defect of the pole piece through a vision algorithm; In the step of receiving the deviation detection signal and sending the liquid telecentric lens control signal, it further includes: Receive the deviation detection signal and delay the sending of the liquid telecentric lens control signal processed by the correction algorithm; The delay is based on the distance between the laser alignment instrument and the liquid telecentric lens, the moving speed of the conveyor belt, and the sampling frequency parameter information of the laser alignment instrument to calculate the delay amount of sending the liquid telecentric lens control signal; In the step of receiving the deviation detection signal and delaying the sending of the liquid telecentric lens control signal processed by the correction algorithm, it further includes: pre-measure and obtain the algorithm parameter information and configure the correction algorithm; Among them, the algorithm parameter information includes the conveyor belt uniform motion speed v, with the unit of m / s; the relative distance L between the laser alignment instrument and the liquid telecentric lens in the conveyor belt movement direction, with the unit of m; the relative distance dx between the laser alignment instrument and the liquid telecentric lens in the imaging depth of field direction, with the unit of m; the sampling frequency of the laser alignment instrument is f, with the unit of Hz; the deviation output for the nth time is x n , with the unit of m; the communication system transmission delay is δt1, with the unit of s; the diopter of the liquid telecentric lens for the nth time is Ф n , with the unit of dpt; the response delay of the liquid telecentric lens is δt2, with the unit of s; the working distance sensitivity of the entire liquid telecentric lens group is K, with the unit of m / dpt; The correction algorithm is:

4. The high-speed feedforward method for pole piece detection according to claim 3, characterized in that In the step of performing image acquisition through the liquid telecentric lens to obtain an image of the end face of the pole piece, it further includes: Simultaneously turn on the annular LED array to irradiate the end face of the pole piece for fill light.

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