Linear motor rotor position searching method and system based on absolute position sample library

Abstract

The invention is suitable for the technical field of position measurement, and provides a linear motor mover position searching method and system based on an absolute position sample library, and the method comprises the steps: constructing a multi-speed sample library based on a preset target shooting source and a measurement system of a linear motor; performing feature value extraction on each row of uniform speed sample sequence of the multi-speed sample library to construct a feature value sample library; acquiring image information shot by the linear array camera in the moving process of the linear motor rotor; carrying out feature value parallel matching on the image information in a feature value sample library on the basis of an FPGA (Field Programmable Gate Array) platform; and obtaining the displacement of the linear motor rotor according to the characteristic value matching result. According to the method, the search time can be greatly shortened and the real-time performance of the position detection of the rotor of the linear motor can be improved in a mode of matching the characteristic values of the sample library in parallel, and the accuracy of the position detection of the rotor can be further improved by collecting more line image information because the matching time is shortened.

Description

Technical Field

[0001] The present invention belongs to the technical field of position measurement, and particularly relates to a linear motor mover position search method and system based on an absolute position sample library. Background Art

[0002] Permanent magnet synchronous linear motors (PMSLMs) are widely used in high-precision machining equipment such as computer numerical control machine tools, laser processing equipment, and precision motion control systems due to their advantages of simple structure, fast response, high thrust density, high precision, and high efficiency. The control precision of the linear motor affects the operating precision of the machine, and the real-time performance and measurement precision of the linear motor position measurement directly affect the control precision of the linear motor. Therefore, studying the real-time high-precision measurement of the moving position of the linear motor is of great significance to the linear motor servo control system.

[0003] Common methods for measuring the moving position of permanent magnet synchronous motors mainly rely on relevant sensors such as light, electricity, and magnetism to measure displacement. Currently, widely used sensors mainly include grating sensors, laser interferometers, Hall sensors, and magnetic grating sensors, etc. The measurement precision of such sensors is high and can meet the requirements of the processing precision of most devices. The grating sensor has high measurement precision and strong anti-interference performance. However, with the increase in the measurement length, the manufacturing difficulty and cost will increase significantly. The laser interferometer has high measurement precision and can achieve nanoscale measurement. However, the laser interferometer is expensive and vulnerable to system vibration, and there are many limitations in practical applications. Since the Hall sensor is easily interfered by the third harmonic component, it is necessary to filter the magnetic field signal, which increases the complexity of the measurement. The magnetic grating sensor has a long measurement stroke, but it is easily interfered by the magnetic field in a complex industrial environment.

[0004] Another method is based on the detection of the linear motor mover position using digital images. The specific method is to capture an aperiodic vertical stripe image parallel to the motor movement direction by a linear array camera fixed on the linear motor mover, and then put the image into the Matlab program to read the pixel information and perform operations on the image processing algorithm, and finally obtain the mover position information of the linear motor. This method optimizes the mover position detection in two ways. One is to optimize the position detection result through the design of the aperiodic stripe image captured by the camera; the other is to optimize the position detection result by improving the image processing algorithm in the Matlab program.

[0005] However, when the existing digital image measurement technology is applied to the field of linear motor mover position detection, it calculates the sub-pixel displacement between two adjacent images before and after the mover displacement by continuously capturing two adjacent images, and obtains the actual displacement value of the mover through system calibration. For long-distance displacement calculation, it is necessary to continuously capture images multiple times during this displacement process, calculate the sub-pixel displacement between adjacent images, and accumulate the measurement results to obtain the mover position. In each of the multiple consecutive measurement calculations, there is a single error in each measurement, and the accumulation will form an accumulated error; moreover, the sample library constructed by this method is too large. Especially when the measurement accuracy is high and the measurement frequency is high, a very large amount of sample library data needs to be constructed, which leads to too long a time for matching with the images captured by the line array camera in real time, thus affecting the efficiency of position detection, and it is necessary to improve it. Summary of the Invention

[0006] The purpose of the present invention is to provide a linear motor mover position search method and system based on an absolute position sample library, aiming to solve the problem that the matching time of the existing method mentioned in the background technology is too long, thus affecting the efficiency of position detection.

[0007] In the first aspect of the present invention, a linear motor mover position search method based on an absolute position sample library, the method includes the following steps:

[0008] Construct a multi-speed sample library based on the preset target shooting source and measurement system of the linear motor;

[0009] Extract the eigenvalue of each row of the uniform speed sample sequence in the multi-speed sample library, so as to convert the pixel data of 1 row and N columns into a single data with an eigenvalue of X, and convert the pixel data under different uniform speeds stored in the multi-speed sample library into pixel eigenvalues under different uniform speeds, so as to construct an eigenvalue sample library;

[0010] Obtain the image information captured by the line array camera during the movement of the linear motor mover;

[0011] Based on the FPGA platform, perform parallel eigenvalue matching on the image information in the eigenvalue sample library;

[0012] Obtain the displacement of the linear motor mover according to the eigenvalue matching result.

[0013] Further, the method further includes: setting the target shooting source of the linear motor; specifically including:

[0014] Construct an xyz coordinate system, where the axis parallel to the movement axis of the linear motor mover is the x-axis, the axis perpendicular to the movement axis of the linear motor mover is the y-axis, and the axis perpendicular to the x-axis and the y-axis is the z-axis;

[0015] Construct a non-periodic image with a certain stripe density as the target shooting source. The gray value of this image gradually changes according to a function signal along the x-axis, and the gray values of the pixel points on the y-axis are the same;

[0016] Among them, the size of the image is M×N, and the gray gradient along the x-axis is G x and the sum of gray gradients is W x , satisfying:

[0017]

[0018] Furthermore, the method further includes:

[0019] Preset the measurement system of the linear motor, specifically including:

[0020] Based on the relative position relationship between the built linear motor and the camera, determine the shooting parameters of the camera, and the shooting parameters at least include the aperture and the focal length;

[0021] Calculate the calibration coefficient ε of the camera through a calibration experiment. The calibration coefficient ε is the actual distance corresponding to one pixel in the image captured by the camera at the set magnification, and obtain the measurement system of the linear motor.

[0022] Furthermore, the step of constructing a multi-speed sample library based on the preset target shooting source and measurement system of the linear motor specifically includes:

[0023] Control the mover to move at a constant speed from the starting point of motion, scan the target shooting source at a constant frequency, obtain a one-dimensional image signal sequence, and construct a constant-speed sample sequence;

[0024] Control the mover to move at a constant speed at different speeds to obtain different speed sample sequences;

[0025] Combine different speed sample sequences to form a multi-speed sample library.

[0026] Furthermore, the step of performing parallel matching of eigenvalue on the image information in the eigenvalue sample library based on the FPGA platform specifically includes:

[0027] When the FPGA platform inputs the first group of images, calculate the eigenvalues of each row of images in this group to obtain the eigenvalues of this group of images; where the first group of images includes the first row of images or the first i rows of images, and i is greater than or equal to 2;

[0028] In the eigenvalue sample library, simultaneously match the eigenvalues of this group of images with different constant-speed sample sequence groups, and select the constant-speed sample sequence groups with a matching degree greater than the preset threshold;

[0029] Divide the selected uniform sample sequence group and perform simultaneous matching through the input second group of images to obtain a sample sequence that meets the pixel feature values;

[0030] Obtain the current position information of the mover based on this sample sequence and output the mover position information.

[0031] In the second aspect of the present invention, a linear motor mover position search system based on an absolute position sample library is used for the method as described above. The system includes:

[0032] A first sample library construction module that constructs a multi-speed sample library based on a preset target shooting source and measurement system of a linear motor;

[0033] A second sample library construction module that extracts eigenvalue for each row of uniform sample sequences in the multi-speed sample library, thereby converting the pixel data of 1 row and N columns into a single data with an eigenvalue of X, and converting the pixel data under different uniform speeds stored in the multi-speed sample library into pixel feature values under different uniform speeds to construct an eigenvalue sample library;

[0034] An information acquisition module that acquires image information captured by a line array camera during the movement of the linear motor mover;

[0035] A feature parallel matching module that performs parallel eigenvalue matching on the image information in the eigenvalue sample library based on the FPGA platform;

[0036] A displacement output module that obtains the displacement of the linear motor mover according to the eigenvalue matching result.

[0037] Further, the feature parallel matching module includes:

[0038] An eigenvalue calculation sub-module that calculates the eigenvalues of each row of images in the group when the FPGA platform inputs the first group of images to obtain the eigenvalues of the group of images; where the first group of images includes the first row of images or the first i rows of images, and i is greater than or equal to 2;

[0039] A similar sample selection sub-module that simultaneously matches the eigenvalues of the group of images with sample sequence groups under different uniform speeds in the eigenvalue sample library and selects the uniform sample sequence group with a matching degree greater than a preset threshold;

[0040] An eigenvalue matching sub-module that divides the selected uniform sample sequence group and performs simultaneous matching through the input second group of images to obtain a sample sequence that meets the pixel feature values;

[0041] A matching result output sub-module that obtains the current position information of the mover based on this sample sequence and outputs the mover position information.

[0042] In a third aspect of the present invention, a computer device includes a processor and a memory, and a computer program is stored on the memory. When the computer program is executed by the processor, the processor is caused to execute the steps of the method.

[0043] In a fourth aspect of the present invention, a computer-readable storage medium stores a computer program. When the computer program is executed by a processor, the processor is caused to execute the steps of the method.

[0044] A linear motor mover position search method based on an absolute position sample library provided by the present invention constructs a corresponding eigenvalue sample library according to the absolute position sample library, thereby optimizing the volume of the sample library and improving the efficiency of the search strategy; after obtaining the target source image (or target shooting source) during the movement of the mover, taking advantage of the high-speed and parallel processing of FPGA, the matching of the currently captured image information and the sample library information is implemented within the FPGA hardware, and the matching time is further shortened through parallel matching, thereby improving the detection efficiency of the entire mover detection and significantly improving the position measurement efficiency of the linear motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a flowchart of a linear motor mover position search method based on an absolute position sample library provided by an embodiment of the present invention;

[0046] Figure 2 is the target source image (or target shooting source) used in the method in an embodiment of the present invention;

[0047] Figure 3 is an example of a linear motor model in an embodiment of the present invention;

[0048] Figure 4 is a flowchart of the construction of the eigenvalue sample library in an embodiment of the present invention;

[0049] Figure 5 is a principle flowchart of a linear motor mover position search method based on an absolute position sample library provided by an embodiment of the present invention;

[0050] Figure 6 is a structural block diagram of a linear motor mover position search system based on an absolute position sample library provided by an embodiment of the present invention;

[0051] Figure 7 is an internal structural block diagram of a computer device in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0053] Figure 1 It is a flowchart of a linear motor mover position search method based on an absolute position sample library provided by an embodiment of the present invention; Figure 2 It is the target shooting source used in this method in the embodiment of the present invention; Figure 3 It is an example of a linear motor model in the embodiment of the present invention.

[0054] Figure 3 Among them, the linear motor model includes a linear motor base 2, a linear motor mover 1, a linear motor stator and a guide rail. The linear motor mover 1 can move along the guide rail under the mutual magnetic force with the linear motor stator; based on this linear motor model, a line array scanning camera 3 is fixed on the linear motor mover 1; a target shooting source 4 is set on the linear motor base 2 to build a mover position detection platform.

[0055] In one embodiment, a linear motor mover position search method based on an absolute position sample library is proposed, which specifically may include the following steps S101 to S105;

[0056] S101, construct a multi-speed sample library based on the preset target shooting source and measurement system of the linear motor;

[0057] In this step, setting the target shooting source of the linear motor includes:

[0058] Construct an xyz coordinate system, where the axis parallel to the movement axis of the linear motor mover is the x-axis, the axis perpendicular to the movement axis of the linear motor mover is the y-axis, and the axis perpendicular to the x-axis and y-axis is the z-axis;

[0059] Construct an image that is non-periodic and has a certain stripe density as the target shooting source. The gray value of this image gradually changes according to a function signal on the x-axis, and the gray values of the pixel points on the y-axis are the same;

[0060] Among them, the size of the image is M×N, and the gray gradient along the x-axis is G x and the sum of the gray gradients is W x , satisfying:

[0061]

[0062] M0 and N0 are the zeros of M and N respectively, or can be regarded as the starting point of the mover's movement.

[0063] In this step, a line-array scanning camera 3 is fixed on the moving element of the linear motor, and the printed target source image (or the target shooting source 4) is fixed on the base 2 of the linear motor, making the x-axis of the image parallel to the moving axis of the moving element of the linear motor and placing it directly in front of the camera, with the optical axis of the camera perpendicular to the printed target source image. Adjust the aperture and focal length of the line-array scanning camera 3 to make the captured image clear. Calculate the calibration coefficient of the line-array scanning camera 3 through a calibration experiment ε , and the calibration coefficient ε is the actual distance corresponding to one pixel in the image captured by the camera at the set magnification. The calculation formula for the calibration coefficient ε is:

[0064] ε = Δy / Δp;

[0065] where, assuming that the displacement between images obtained by image measurement calculation is Δp and the actual displacement is Δy.

[0066] Make the moving element of the linear motor move at a constant speed from the starting point. The line-array scanning camera 3 scans the target source image at a constant frequency to obtain a one-dimensional signal sequence and construct a constant-speed sample sequence. Repeat this operation multiple times. From the same starting point of motion, make the moving element of the linear motor move at a constant speed at different speeds. A multi-speed sample library is constructed from the sample sequences at different speeds.

[0067] S102. Extract the eigenvalues from each row of the constant-speed sample sequences in the multi-speed sample library, so as to convert the pixel data of 1 row and N columns into a single data with an eigenvalue of X, and convert the pixel data at different constant speeds stored in the multi-speed sample library into pixel eigenvalues at different constant speeds to construct an eigenvalue sample library;

[0068] As Figure 4 shown, exemplarily, each row of the constant-speed sample sequences in the multi-speed sample library is respectively a constant-speed 1 sample sequence, a constant-speed 2 sample sequence, a constant-speed 3 sample sequence, a constant-speed 4 sample sequence, etc.; among them, the pixel data of 1 row and N columns is converted into an eigenvalue of X, that is, the first group of image signal eigenvalues, the first group of image signal eigenvalues, the second group of image signal eigenvalues, the third group of image signal eigenvalues, the fourth group of image signal eigenvalues, up to the Xth group of image signal eigenvalues.

[0069] S103. Obtain the image information captured by the line camera during the motion of the moving element of the linear motor;

[0070] In this step, when the linear motor starts to move, the line array scanning camera 3 starts to capture images; it is set to obtain one row of images every 50 rows for matching with the eigenvalue sample library. The FPGA platform is set to have a clock cycle of 10 nanoseconds. The line array scanning camera 3 captures 1000 pixels per row, and the line rate is 20 kHz (i.e., 20000 rows are captured per second). At this time, the interval between two rows of image information in the FPGA platform is 500 us. Suppose there are 10 sets of sample sequences at different uniform speeds stored in the eigenvalue sample library, and each set of sample sequences contains 10000 eigenvalue of image signal series.

[0071] S104, based on the FPGA platform, perform parallel eigenvalue matching on the image information in the eigenvalue sample library; among them, the FPGA platform can be built by one or more FPGA chips.

[0072] Exemplarily, optional FPGA chips include Virtex UltraScale+VU9P, VU13P, VU19P, or ZynqUltraScale+XCZU9EG, XCZU19EG, etc.

[0073] Exemplarily, as Figure 5 shown, when the first row of images is input, the FPGA platform starts to calculate the eigenvalue of this row with a one-beat delay; when the eigenvalue is obtained, this eigenvalue is simultaneously matched with the eigenvalues in 10 sets of different uniform-speed sample sequences in the eigenvalue sample library to obtain the number of groups where the similar sample eigenvalues are located. At this time, there may be more than one group.

[0074] Since there is an interval of 500 us between two rows of image information, and it takes at most 100 us to match 10000 data in each group, there is a lot of time margin.

[0075] Take the n groups that match similar eigenvalues as the eigenvalue library for the next row of image matching; n ranges from 1 to 10. When the eigenvalue of the next row of images is calculated, the running speed of the linear motor mover is obtained through the relationship value between the eigenvalues of these two rows of images, so as to remove the sample groups that do not meet the uniform speed.

[0076] After that, the eigenvalues within the selected sample groups are divided into 10 groups, and at the same time, the eigenvalues of the next row of pixels are matched. After obtaining the approximate matching eigenvalues, the pixel displacement of the mover during this period is obtained according to the relationship with the eigenvalues matched by the first row of pixels, so as to obtain the actual displacement of the mover.

[0077] It should be noted that the matching method of the image pixel data (or image data) transmitted to the FPGA platform subsequently is the same as that of the first and second rows of images. That is, the corresponding eigenvalue is obtained based on the image pixel data of the current row, and then this value is simultaneously matched with the 10 groups of eigenvalues divided within the selected constant-speed sample group to find similar eigenvalues, and the displacement of the mover is obtained through the relationship between the current sample eigenvalue and the corresponding sample eigenvalue of the previous row.

[0078] In some examples, when inputting the first few rows (such as: two rows, three rows, etc.) of images, the FPGA platform starts calculating the eigenvalues of these rows with a one-beat delay; in this way, the eigenvalues of the first few rows of input images can be calculated as the sequence of the first matching eigenvalues, improving the matching accuracy.

[0079] S105, obtain the displacement of the linear motor mover according to the eigenvalue matching result.

[0080] In this embodiment, the described search method is implemented through the FPGA platform. Since the FPGA platform can achieve high-speed parallel processing, it can meet the method of parallel matching of the sample library, overcoming the deficiency that the current MATLAB software can only perform linear search. By the method of parallel matching of the sample library eigenvalues, the search time can be greatly shortened, improving the real-time performance of the linear motor mover position detection. Also, because the matching time is shortened, more line image information can be collected in the same amount of time, thereby further improving the accuracy of the mover position detection.

[0081] In another embodiment, as Figure 6 shown, a linear motor mover position search system based on an absolute position sample library, the system includes:

[0082] The first sample library construction module 100 constructs a multi-speed sample library based on the preset target shooting source and measurement system of the linear motor;

[0083] In this embodiment, the line array scanning camera 3 is fixed on the linear motor mover 1 (or mover), and follows the linear motor mover to capture the target source image fixed in front of the mover in real time; the collected sequence image signal is transmitted to the computer to obtain the target image information, and the actual displacement of the mover is obtained through the analysis of the computer system.

[0084] The second sample library construction module 200 is used to extract eigenvalues from each row of the constant-speed sample sequence of the multi-speed sample library, so as to convert the pixel data of 1 row and N columns into a single data with an eigenvalue of X, and convert the pixel data under different constant speeds stored in the multi-speed sample library into pixel eigenvalues under different constant speeds to construct an eigenvalue sample library; X takes a natural number between 1 and N.

[0085] An information acquisition module 300 is configured to acquire image information captured by a line array camera during the movement of a linear motor mover;

[0086] A feature parallel matching module 400 is configured to perform parallel matching of feature values on the image information in a feature value sample library based on an FPGA platform;

[0087] A displacement output module 500 is configured to obtain the displacement of the linear motor mover according to the feature value matching result.

[0088] In this embodiment, a multi - speed sample library is constructed, so that the exposure time of the camera can be optimized under different mover movement speed conditions to reduce the impact on the quality of the sample images. At the same time, by adjusting the sample interval, the redundant calculation of the sample library search is reduced, and the over - simplification of the search process is avoided. Thus, on the premise of ensuring the measurement accuracy, the measurement efficiency is significantly improved.

[0089] In this embodiment, the feature parallel matching module includes:

[0090] A feature value calculation sub - module, when a first group of images is input to the FPGA platform, calculates the feature values of each row of images in this group to obtain the feature values of this group of images; where the first group of images includes the first row of images or the first i rows of images, and i is greater than or equal to 2;

[0091] A similar sample selection sub - module is configured to simultaneously match the feature values of this group of images with sample sequence groups at different constant speeds in the feature value sample library, and select the sample sequence groups with a matching degree greater than a preset threshold;

[0092] A feature value matching sub - module is configured to divide the selected sample sequence groups at constant speed and perform simultaneous matching through the input second group of images to match and obtain a sample sequence that conforms to the pixel feature values;

[0093] A matching result output sub - module is configured to obtain the current position information of the mover according to this sample sequence and output the mover position information.

[0094] In another embodiment, a computer device includes a processor and a memory, and a computer program is stored on the memory. When the computer program is executed by the processor, the processor executes steps S101 to S105 of the method;

[0095] S101. Based on a preset target shooting source and measurement system of a linear motor, construct a multi - speed sample library;

[0096] S102. Extract eigenvalues from each row of the uniform speed sample sequences in the multi-speed sample library, thereby converting the pixel data of 1 row and N columns into a single data with an eigenvalue of X, and transforming the pixel data at different uniform speeds stored in the multi-speed sample library into pixel eigenvalues at different uniform speeds to construct an eigenvalue sample library;

[0097] S103. Obtain the image information captured by the line array camera during the movement of the linear motor mover;

[0098] S104. Based on the FPGA platform, perform parallel eigenvalue matching on the image information in the eigenvalue sample library;

[0099] S105. Obtain the displacement of the linear motor mover according to the eigenvalue matching result.

[0100] In another embodiment, a computer-readable storage medium stores a computer program thereon. When the computer program is executed by a processor, the processor executes steps S101 to S105 of the method;

[0101] S101. Based on a preset target shooting source and measurement system of a linear motor, construct a multi-speed sample library;

[0102] S102. Extract eigenvalues from each row of the uniform speed sample sequences in the multi-speed sample library, thereby converting the pixel data of 1 row and N columns into a single data with an eigenvalue of X, and transforming the pixel data at different uniform speeds stored in the multi-speed sample library into pixel eigenvalues at different uniform speeds to construct an eigenvalue sample library;

[0103] S103. Obtain the image information captured by the line array camera during the movement of the linear motor mover;

[0104] S104. Based on the FPGA platform, perform parallel eigenvalue matching on the image information in the eigenvalue sample library;

[0105] S105. Obtain the displacement of the linear motor mover according to the eigenvalue matching result.

[0106] Figure 7The internal structure diagram of a computer device in an embodiment is shown. The computer device may specifically be a computing terminal (or a server). The computer device includes a processor, a memory, a network interface, an input device, and a display screen connected through a system bus. Among them, the memory includes a non-volatile storage medium and an internal memory. The non-volatile storage medium of the computer device stores an operating system and may also store a computer program. When the computer program is executed by the processor, the processor can implement the above method. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can execute the above method. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen. The input device of the computer device may be a touch layer covering the display screen, or may be a button, a trackball, or a touchpad provided on the housing of the computer device, or may also be an external keyboard, a touchpad, or a mouse, etc.

[0107] It should be understood that although the steps in the flowcharts of the embodiments of the present invention are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in each embodiment may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least a part of other steps or sub-steps or stages of other steps.

[0108] The above-described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

[0109] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A linear motor mover position search method based on an absolute position sample library, characterized in that: The method comprises: Based on the preset linear motor target shooting source and measurement system, a multi-speed sample library is constructed; Extracting feature values ​​from each row of uniform speed sample sequences in the multi-speed sample library, thereby converting pixel data of 1 row and N columns into single data with a feature value of X, and converting pixel data at different uniform speeds stored in the multi-speed sample library into pixel feature values ​​at different uniform speeds, so as to construct a feature value sample library; Acquire image information captured by a linear array camera during the motion of the linear motor mover; Based on the FPGA platform, performing parallel matching of eigenvalues ​​of the image information in the eigenvalue sample library; The displacement of the linear motor rotor is obtained according to the eigenvalue matching results.

2. The method according to claim 1, characterized in that: The method further includes: setting a target shooting source of the linear motor; specifically including: Construct an xyz coordinate system, wherein the axis parallel to the linear motor mover motion axis is the x-axis, the axis perpendicular to the linear motor mover motion axis is the y-axis, and the axis perpendicular to the x-axis and the y-axis is the z-axis; Construct a non-periodic image with a certain fringe density as the target shooting source. The grayscale value of the image on the x-axis gradually changes according to the function signal, and the grayscale value of the pixel points on the y-axis is the same. The image size is M×N, and the grayscale gradient along the x-axis is G. x , grayscale gradient and W x ,satisfy:

3. The method according to claim 1 or 2, characterized in that: The method further includes: presetting a measurement system of the linear motor, specifically including: Based on the relative position relationship between the built linear motor and the camera, determine the shooting parameters of the camera, which at least include aperture and focal length; The calibration coefficient ε of the camera is calculated through a calibration experiment. The calibration coefficient ε is the actual distance corresponding to one pixel in the image taken by the camera at a set magnification, and the measurement system of the linear motor is obtained.

4. The method according to claim 1, characterized in that: The step of constructing a multi-speed sample library based on the preset target shooting source and measurement system of the linear motor specifically includes: The mover is controlled to move at a uniform speed from the starting point, and the target shooting source is scanned at a constant frequency to obtain a one-dimensional image signal sequence and construct a uniform speed sample sequence; Control the mover to move at different speeds at a uniform speed to obtain sample sequences at different speeds; Combine different speed sample sequences to form a multi-speed sample library.

5. The method according to claim 1, characterized in that The step of performing parallel feature value matching on the image information in the feature value sample library based on the FPGA platform specifically includes: When the FPGA platform inputs the first group of images, the characteristic values ​​of each row of images in the group are calculated to obtain the characteristic values ​​of the group of images; wherein the first group of images includes the first row of images or the first i rows of images, i being greater than or equal to 2; In the feature value sample library, the feature values ​​of the group of images are simultaneously matched with the sample sequence groups at different uniform speeds, and the uniform speed sample sequence group with a matching degree greater than a preset threshold is selected; The selected uniform speed sample sequence group is divided, and the second group of images are input for simultaneous matching to obtain a sample sequence that meets the pixel feature value; The current position information of the mover is obtained according to the sample sequence, and the position information of the mover is output.

6. A linear motor mover position search system based on an absolute position sample library, used in the method according to any one of claims 1 to 5, characterized in that: The system comprises: The first sample library construction module constructs a multi-speed sample library based on a preset target shooting source and measurement system of the linear motor; The second sample library construction module is used to extract feature values ​​from each row of uniform speed sample sequences in the multi-speed sample library, thereby converting pixel data of 1 row and N columns into single data with a feature value of X, so that the pixel data at different uniform speeds stored in the multi-speed sample library are converted into pixel feature values ​​at different uniform speeds, so as to construct a feature value sample library; An information acquisition module is used to acquire image information captured by a linear array camera during the motion of the linear motor mover; A feature parallel matching module, used for performing feature value parallel matching on the image information in a feature value sample library based on an FPGA platform; The displacement output module is used to obtain the displacement of the linear motor mover according to the eigenvalue matching result.

7. The system according to claim 6, characterized in that The feature parallel matching module comprises: The eigenvalue calculation submodule calculates the eigenvalues ​​of each row of images in the group when the FPGA platform inputs the first group of images to obtain the eigenvalues ​​of the group of images; wherein the first group of images includes the first row of images or the first i rows of images, i being greater than or equal to 2; The similar sample selection submodule is used to simultaneously match the feature values ​​of the group of images with the sample sequence groups at different uniform speeds in the feature value sample library, and select the uniform speed sample sequence group with a matching degree greater than a preset threshold; The feature value matching submodule is used to divide the selected uniform speed sample sequence group, and simultaneously match the second group of input images to obtain a sample sequence that meets the pixel feature value; The matching result output submodule is used to obtain the current position information of the mover according to the sample sequence and output the position information of the mover.

8. A computer device, characterized in that: The computer device comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the method according to any one of claims 1 to 5.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor executes the steps of the method according to any one of claims 1 to 5.

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