Method and system for measuring position of rotor of linear motor

Abstract

The invention is suitable for the technical field of position measurement, and provides a linear motor mover position measurement method and system, 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; setting a single measurement period of rotor position measurement according to the position loop frequency of the linear motor; registering a reference image of a single measurement period according to the multi-speed sample library; in a single measurement period, collecting a target shooting source at a first collection frequency to obtain i collection images; calculating the displacement between the acquired image and the reference image for reversely deducing the mover movement speed in the acquisition period and taking the mover movement speed as mover instantaneous speed; and according to the mover instantaneous speed and the reference image, estimating the mover position at the feedback moment, and determining the actual mover displacement through the mover position at the feedback moment. According to the invention, a multi-speed sample library is constructed, rotor position measurement under multiple working conditions is provided, and the method is better suitable for practical application of rotor position measurement.

Description

Technical Field

[0001] The invention belongs to the technical field of position measurement, and in particular relates to the position measurement of a linear motor mover, and specifically discloses a linear motor mover position measurement method and system. Background Art

[0002] The permanent magnet synchronous linear motor (PMLSM) servo control system has the advantages of fast acceleration, small steady-state error, small overshoot, and good thrust quality. It is often used in industrial fields such as high-end machine tools and laser cutting machines. The accuracy of motor position feedback is the key to achieving high control accuracy of the servo control system. The anti-interference performance of position detection will affect the robustness of the servo control system. Therefore, it is necessary to explore a high-precision and robust permanent magnet synchronous motor arm position measurement method.

[0003] In recent years, position measurement technology based on machine vision has been widely used in target tracking and positioning in the field of UAV remote sensing control due to its advantages such as high detection accuracy, strong practicality and strong robustness. Most importantly, its cost is independent of the measurement range and mainly depends on the cost of the camera. Therefore, some studies have adopted image measurement technology to detect the position of a large-stroke straight line.

[0004] At present, the precise measurement of the motion position of long-stroke linear motors mainly uses laser interferometers, magnetic grating position sensors and grating position sensors. The measurement accuracy of this type of sensor can reach the nanometer level, meeting the processing accuracy requirements of most devices. However, laser interferometers are expensive, susceptible to system vibration, and need to work in a dry and clean environment. Magnetic grating position sensors are easily affected by system environmental noise, especially the interference of system current on the sensor magnetic field. Grating position sensors have strong anti-interference performance, but as the measuring length increases, the manufacturing difficulty and cost of the equipment will also increase exponentially. And according to the characteristics of incremental sensors, especially when the operating temperature changes, the cumulative error of the system will increase with the increase of stroke.

[0005] The existing digital image measurement technology is applied to the field of linear motor mover position detection. It calculates the sub-pixel displacement of the two images before and after the mover displacement and obtains the actual displacement value of the mover through system calibration. This measurement method will cause error accumulation during the measurement process. Therefore, in order to solve the problem of error accumulation during position measurement, it is necessary to provide new ideas for linear motor mover position measurement under long stroke conditions. Summary of the invention

[0006] The purpose of the present invention is to provide a method for measuring the position of a linear motor rotor, aiming to further improve the measurement accuracy and robustness of existing image measurement methods; this method solves the problem of cumulative errors existing in traditional image measurement methods (such as CN202310672462.7) by constructing an image sample sequence (providing a fixed position reference point for measurement), and better adapts to the measurement problem of the position of a linear motor rotor under large stroke conditions; a multi-speed sample library is constructed, and a method for measuring the position of a linear motor rotor under multiple working conditions is provided, which is better adapted to the practical application of linear motor rotor position measurement, and provides a low-cost, high-precision, and high-robustness measurement method for large-stroke linear motor rotor position detection.

[0007] The present invention is implemented in this way: a method for measuring the position of a linear motor mover, the method comprising the following steps:

[0008] Based on the preset linear motor target shooting source and measurement system, a multi-speed sample library is constructed;

[0009] According to the position loop frequency of the linear motor, a single measurement cycle of the mover position measurement is set; wherein the single measurement cycle includes instantaneous speed measurement and mover position prediction;

[0010] registering a reference image of a single measurement cycle according to the multi-speed sample library;

[0011] In a single measurement cycle, the target shooting source is acquired at a first acquisition frequency to obtain i acquired images; wherein the first acquisition frequency is greater than the position loop frequency, and i is a natural number;

[0012] Calculate the displacement between the acquired image and the reference image to infer the moving speed of the mover during the acquisition period and use it as the instantaneous speed of the mover;

[0013] The position of the mover at the moment of feedback is estimated according to the instantaneous speed of the mover and the reference image, and the actual displacement of the mover is determined by the position of the mover at the moment of feedback.

[0014] Another object of the present invention is to provide a linear motor mover position measurement system, the linear motor mover position measurement system comprising:

[0015] A database module is used to build a multi-speed sample library based on the preset target shooting source and measurement system of the linear motor;

[0016] A measurement cycle setting module, used to set a single measurement cycle of the mover position measurement according to the position loop frequency of the linear motor; wherein the single measurement cycle includes instantaneous speed measurement and mover position prediction;

[0017] A captured image registration module, used for registering a reference image of a single measurement cycle according to the multi-speed sample library;

[0018] An image acquisition module, used to acquire a target shooting source at a first acquisition frequency within a single measurement cycle to obtain i acquired images; wherein the first acquisition frequency is greater than the position loop frequency, and i is a natural number;

[0019] The instantaneous speed measurement module is used to calculate the displacement between the acquired image and the reference image, and is used to infer the moving speed of the mover during the acquisition period and serve as the instantaneous speed of the mover;

[0020] The mover position prediction module is used to estimate the mover position at the feedback moment according to the mover instantaneous speed and the reference image, and determine the actual mover displacement through the mover position at the feedback moment.

[0021] Another object of the present invention is to provide a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the linear motor mover position measurement method.

[0022] Another object of the present invention is to provide a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the processor executes the steps of the linear motor mover position measurement method.

[0023] The present invention provides a method for measuring the position of a linear motor mover. The method controls the measurement cycle according to a position loop and divides the measurement cycle into a number of small cycles. The method obtains the instantaneous speed of the mover by taking multiple shots of a camera within a single measurement cycle and calculating the displacement of the captured image relative to a single-cycle sample reference image. The position of the mover at the moment of position feedback is estimated by a motion formula. The measurement has strong flexibility and can well adapt to the complex operating conditions of the mover. The method calculates the instantaneous speed of the mover to make a high-precision estimate of the mover position at the moment of feedback, and can achieve pre-feedback or real-time feedback without the problem of feedback delay, thereby greatly improving real-time performance and control accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A principle flow chart of a linear motor rotor position measurement method provided by an embodiment of the present invention;

[0025] Figure 2 is a target source image (or a target shooting source) used by the method in the embodiment of the present invention;

[0026] Figure 3 This is an example of a linear motor model in an embodiment of the present invention;

[0027] Figure 4 An application environment diagram of a linear motor mover position measurement method provided by an embodiment of the present invention;

[0028] Figure 5 is a flow chart of constructing a multi-speed sample library in an embodiment of the present invention;

[0029] Figure 6 A flow chart of a method for measuring the position of a linear motor rotor provided by an embodiment of the present invention;

[0030] Figure 7 A sub-flow chart of the method in an embodiment of the present invention;

[0031] Figure 8 A structural block diagram of a linear motor mover position measurement system provided by an embodiment of the present invention;

[0032] Fig. 9 The figure is a block diagram of the internal structure of a computer device in an embodiment of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with 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 intended to limit the present invention.

[0034] Figure 3 1 is an example of a linear motor model in an embodiment of the present invention; wherein the linear motor 100 includes a base 101 provided with a stator, a mover 102, a camera 130 provided on the mover 102, and a target shooting source 103 provided on the base 101; Figure 4 An application environment diagram of a linear motor rotor position measurement method provided by an embodiment of the present invention, such as Figure 4 As shown, in the application environment, a terminal 110 and a computer device 120 are included.

[0035] The computer device 120 may be an independent physical server or terminal, or a server cluster composed of multiple physical servers, or a cloud server that provides basic cloud computing services such as cloud servers, cloud databases, cloud storage, and CDN.

[0036] The terminal 110 may be a smart phone, a tablet computer, a laptop computer, a desktop computer, a smart speaker, a smart watch, etc., but is not limited thereto. The terminal 110 and the computer device 120 may be connected via a network and may communicate with the camera 130; the camera 130 may be a linear array camera (i.e., a line scan camera), which is not limited in this embodiment.

[0037] In one embodiment, a linear motor rotor position measurement method is proposed. This embodiment mainly applies the method to Figure 4 The terminal 110 (or server) in FIG. 1 is used as an example to illustrate. A method for measuring the position of a linear motor rotor, the specific flow chart of which can be referred to in FIG. Figure 6 , the method comprises the following steps:

[0038] Step S101, constructing a multi-speed sample library based on a preset target shooting source and measurement system of the linear motor;

[0039] For example, Figure 5 As shown, the multi-speed sample library may be referred to as a sample library, including a plurality of image sample sequences (e.g., sample sequence 1, sample sequence 2, sample sequence 3, etc.), each image sample sequence including a plurality of one-dimensional image signal sequences (e.g., image signal sequence 1, image signal sequence 2, image signal sequence 3, etc.);

[0040] Step S102, setting a single measurement cycle of the mover position measurement according to the position loop frequency of the linear motor; wherein the single measurement cycle includes instantaneous speed measurement and mover position prediction;

[0041] Exemplarily, in the step of setting a single measurement period of the mover position measurement according to the position loop frequency of the linear motor, the position loop frequency is set to 100 Hz and the single measurement period is set to 0.01 seconds.

[0042] It is understandable that the position loop is mainly used to control the position of the motor to ensure that the motor can accurately reach the specified position state; it generates a position error signal by receiving the target position signal and comparing it with the current actual position of the motor. This error signal is transmitted to the speed loop and current loop to adjust the motor speed and torque to make the motor move in the direction of reducing the position error.

[0043] Step S103, registering a reference image of a single measurement cycle according to the multi-speed sample library;

[0044] Exemplarily, the acquisition period of the captured image is less than the single measurement period, for example: the single measurement period is set to 0.01 seconds, and the acquisition period can be 0 seconds to 0.006 seconds;

[0045] First, define the reference image. For the reference image of a single measurement cycle, the reference image h0 is the sample image in the sample library that is closest to the estimated mover position measured in the previous measurement cycle.

[0046] Step S104, within a single measurement cycle, the target shooting source is acquired at a first acquisition frequency to obtain i acquired images; wherein the first acquisition frequency is greater than the position loop frequency, and i is a natural number;

[0047] Wherein, the first acquisition frequency may be 0.006;

[0048] The target source image is collected in one dimension, and the collected images are g1, g2, g3, ... (the specific number of collected images is determined by the camera shooting frequency, and the collection period is 0 seconds to 0.006 seconds for a single measurement period). The collected image g is calculated by the local upsampling algorithm based on NCC (LUNCC) i The displacement from the reference image is Δx1, Δx2, Δx3, ….

[0049] For the local upsampling algorithm, the image normalization cross-correlation detection algorithm is used for feature registration of the captured image in the sample library. Local sampling is performed on the calculated peak area, and the least squares method is used to perform curve fitting on the upsampled area, refine the peak curve, and relocate the maximum point to obtain the sub-pixel level inter-image displacement measurement, that is, complete the calculation of displacement Δx1, Δx2, Δx3, ...

[0050] Step S105, calculating the displacement between the captured image and the reference image, which is used to infer the moving speed of the mover during the capture period and used as the instantaneous speed of the mover;

[0051] Among them, from the uniform motion formula: X=v*t; it can be known that the motion speed of the mover in this acquisition period can be regarded as instantaneous speed due to the small acquisition time interval; according to the calculated motion speed v, the position of the mover at the feedback moment is calculated and estimated.

[0052] Step S106, estimating the position of the mover at the feedback moment according to the instantaneous speed of the mover and the reference image, and determining the actual displacement of the mover through the position of the mover at the feedback moment.

[0053] In an example of this embodiment, for step S101, the target shooting source of the linear motor may be Figure 2 Non-periodic, fringe image shown; presets for target capture sources, including:

[0054] 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;

[0055] 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.

[0056] Generally, the shooting or scanning frequency of the target shooting source is very fast, so the stripe density of the image should be high enough. In this embodiment, the actual stripe density can be flexibly set according to the needs;

[0057] The image size is M×N, and the grayscale gradient along the x-axis is G. x , the grayscale gradient and W x ,satisfy:

[0058]

[0059] M0 and N0 are the zero points of M and N respectively, or can be regarded as the starting points of the movement of the mover.

[0060] In an example of this embodiment, the preset of the measurement system of the linear motor specifically includes:

[0061] 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;

[0062] 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.

[0063] In an example of this embodiment, the relative position relationship between the linear motor and the camera is that the camera is installed on the mover, and the camera shooting direction is aimed at the target shooting source on the base;

[0064] Set ε as the calibration coefficient, ε=Δy / Δp; where it is assumed that the displacement between images calculated by image measurement in the measurement system is Δp, and the actual displacement is Δy.

[0065] In one example of this embodiment, Figure 7 As shown, the step of constructing a multi-speed sample library specifically includes the following steps:

[0066] S201: Control the mover to move at a uniform speed from the starting point, scan the target shooting source at a constant frequency, obtain a one-dimensional image signal sequence, and construct a uniform speed sample sequence;

[0067] S202: Control the mover to perform uniform motion at different speeds to obtain sample sequences at different speeds;

[0068] S203: Combining different speed sample sequences to form a multi-speed sample library.

[0069] In an example of this embodiment, in the step of registering the reference image of a single measurement cycle according to the multi-speed sample library, the registration adopts an image normalized cross-correlation detection algorithm (NCC).

[0070] In an example of this embodiment, the step of determining the actual displacement of the mover by the position of the mover at the feedback moment according to the instantaneous speed of the mover and the position of the mover at the reference image estimation feedback moment specifically includes:

[0071] Establish a motion function that satisfies: X e =v*a+X m ;

[0072] Where v is the instantaneous velocity of the actuator, a is the function parameter, which is 0.004, and X m is the distance of the last image in the acquisition cycle, X e The displacement between the estimated position of the mover and the reference image for this measurement period;

[0073] Then, the position of the actuator at the feedback moment is X i , Xi=X h0 +X e ;

[0074] Where X h0 is the displacement of the reference image from the starting point of the motion;

[0075] The actual displacement of the mover is X, which satisfies: X = X h0 *ε+X e ;

[0076] Wherein, ε is the calibration coefficient, ε=Δy / Δp; wherein, it is assumed that the displacement between images calculated by image measurement in the measurement system is Δp, and the actual displacement is Δy.

[0077] In one example, for the next measurement cycle, the current speed v is known, a sample sequence with a similar speed is selected, and a sample image in the sample library closest to the predicted position is selected according to the predicted position as the reference image for the next measurement cycle.

[0078] In this embodiment, the position measurement is divided into a single small cycle, and the displacement of the captured image relative to the single-cycle sample reference image is calculated by multiple camera shots within a single measurement cycle to obtain the instantaneous motion speed of the mover; and the position of the mover at the moment of position feedback is estimated based on this, and the measurement method is flexible and can adapt well to the complex operating conditions of the mover. By calculating the instantaneous speed of the mover, the position of the mover at the moment of feedback is estimated with high precision, and pre-feedback or real-time feedback can be achieved, and there is no problem of feedback delay, so that the real-time performance and control accuracy are greatly improved. The traditional mover position measurement method based on image measurement is to calculate the displacement between the two images by shooting two images before and after the displacement to calculate the actual displacement of the mover; and such a measurement method will produce errors in each measurement. When calculating the distance between the mover and the origin, the measurement results need to be accumulated, and the errors are also accumulated in this process, resulting in an increase in the cumulative error; on the contrary, the measurement method of the present invention, because each measurement reference image is a sample library image, it does not rely on the measurement results of the previous measurement cycle, and is directly measured with the starting point of the movement, so the measurement error of the mover position feedback in each measurement cycle is only a single error, which greatly improves the position measurement accuracy of the mover of the large-stroke linear motor.

[0079] In another embodiment, Figure 8 As shown, a linear motor mover position measurement system is used for the linear motor mover position measurement method as described above, and the linear motor mover position measurement system includes:

[0080] The database module 100 is used to construct a multi-speed sample library based on a preset target shooting source and a measurement system of the linear motor;

[0081] The measurement cycle setting module 200 is used to set a single measurement cycle of the mover position measurement according to the position loop frequency of the linear motor; wherein the single measurement cycle includes instantaneous speed measurement and mover position prediction;

[0082] A captured image registration module 300, for registering a reference image of a single measurement cycle according to the multi-speed sample library;

[0083] An image acquisition module 400 is used to acquire a target shooting source at a first acquisition frequency within a single measurement cycle to obtain i acquired images; wherein the first acquisition frequency is greater than the position loop frequency, and i is a natural number;

[0084] The instantaneous speed measurement module 500 is used to calculate the displacement between the acquired image and the reference image, and to infer the moving speed of the mover during the acquisition period, and to use it as the instantaneous speed of the mover;

[0085] The mover position prediction module 600 is used to estimate the mover position at the feedback moment according to the mover instantaneous speed and the reference image, and determine the actual mover displacement through the mover position at the feedback moment.

[0086] In one example of this embodiment, the target shooting source and measurement system of the preset linear motor are as follows: Figure 3 , Figure 4 As shown, the target shooting source 103 is arranged on the base 101, and the length direction of the target shooting source 103 is arranged along the moving direction of the mover;

[0087] Specifically, the target shooting source 103 can be set on the base 101 side of the motor by gluing; the acquisition or collection of the shooting image of the target shooting source 103 can be achieved by a camera 130, such as a linear array CCD (Charge Coupled Device) or other high-speed cameras, and the linear array CCD is set on the side of the mover 102. When the mover 102 moves, the linear array CCD is driven to move synchronously, that is, the movement of the mover and the movement of the linear array CCD are the same, and the time is synchronized.

[0088] In an actual scenario of an embodiment, the field of view of the linear array CCD is relative to the plane of the target shooting source 103, and can completely cover the width or vertical picture of the target shooting source 103; that is, the target shooting source 103 is set on the base 101, and the linear array CCD is set on the side of the mover 102, and the optical axis of the linear array CCD is perpendicular to the plane of the target shooting source 103. In this way, when comparing two adjacent image information, the noise of the two adjacent image information in the longitudinal direction relative to the target shooting source 103 can be ignored, thereby improving the measurement accuracy.

[0089] Fig. 9 The internal structure diagram of a computer device in one embodiment is shown. The computer device may specifically be Figure 4 The terminal 110 (or server) in Fig. 9As shown, 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 a linear motor mover position measurement method. The internal memory may also store a computer program. When the computer program is executed by the processor, the processor can execute a linear motor mover position measurement method. The display screen of the computer device may be a liquid crystal display or an electronic ink display screen. The input device of the computer device may be a touch layer covering the display screen, or a button, trackball or touchpad provided on the computer device housing, or an external keyboard, touchpad or mouse.

[0090] Those skilled in the art will understand that Fig. 9 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0091] In one embodiment, the linear motor mover position measurement system provided by the present application can be implemented in the form of a computer program. The computer program can be Fig. 9 The computer device shown in the figure is run. The memory of the computer device can store various program modules constituting the linear motor mover position measurement system, for example, Figure 7 The computer program composed of various program modules enables the processor to execute the steps of the linear motor mover position measurement method of each embodiment of the present application described in this specification.

[0092] In one embodiment, a computer device is provided. The computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, steps S101 to S106 are implemented.

[0093] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the processor executes steps S101 to S106.

[0094] It should be understood that, although each step in the flow chart of each embodiment of the present invention is shown in sequence according to the indication of the arrow, these steps are not necessarily performed in sequence according to the order indicated by the arrow. Unless there is a clear explanation in this article, the execution of these steps does not have a strict order restriction, and these steps can be performed in other orders. Moreover, at least a portion of the steps in each embodiment may include a plurality of sub-steps or a plurality of stages, and these sub-steps or stages are not necessarily performed at the same time, but can be performed at different times, and the execution order of these sub-steps or stages is not necessarily performed in sequence, but can be performed in turn or alternately with at least a portion of other steps or sub-steps or stages of other steps.

[0095] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0096] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0097] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

[0098] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for measuring the position of a linear motor rotor, characterized in that: The linear motor rotor position measurement method comprises the following steps: Based on the preset linear motor target shooting source and measurement system, a multi-speed sample library is constructed; According to the position loop frequency of the linear motor, a single measurement cycle of the mover position measurement is set; wherein the single measurement cycle includes instantaneous speed measurement and mover position prediction; registering a reference image of a single measurement cycle according to the multi-speed sample library; In a single measurement cycle, the target shooting source is acquired at a first acquisition frequency to obtain i acquired images; wherein the first acquisition frequency is greater than the position loop frequency, and i is a natural number; Calculate the displacement between the acquired image and the reference image to infer the moving speed of the mover during the acquisition period and use it as the instantaneous speed of the mover; The position of the mover at the moment of feedback is estimated according to the instantaneous speed of the mover and the reference image, and the actual displacement of the mover is determined by the position of the mover at the moment of feedback.

2. The linear motor rotor position measurement method according to claim 1, characterized in that: The preset of the target shooting source of the linear motor includes: 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 linear motor rotor position measurement method according to claim 1, characterized in that: The preset of the measurement system of the linear motor specifically includes: 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 linear motor rotor position measurement method according to claim 1, characterized in that: The step of constructing a multi-speed sample library 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 linear motor rotor position measurement method according to claim 1, characterized in that: In the step of setting a single measurement period of the mover position measurement according to the position loop frequency of the linear motor, the position loop frequency is set to 100 Hz and the single measurement period is set to 0.01 seconds.

6. The linear motor rotor position measurement method according to claim 1, characterized in that: In the step of registering the reference image of a single measurement cycle according to the multi-speed sample library, the registration adopts an image normalization cross-correlation detection algorithm.

7. The linear motor rotor position measurement method according to claim 1, characterized in that: The step of determining the actual displacement of the mover by the position of the mover at the feedback moment according to the instantaneous speed of the mover and the position of the mover at the reference image estimation feedback moment specifically includes: Establish a motion function that satisfies: X e =v*a+X m ; Where v is the instantaneous velocity of the actuator, a is the function parameter, which is 0.004, and X m is the distance of the last image in the acquisition cycle, X e The displacement between the estimated position of the mover and the reference image for this measurement period; Then, the position of the actuator at the feedback moment is X i , X i =X h0 +X e ; Where X h0 is the displacement of the reference image from the starting point of the motion; The actual displacement of the mover is X, which satisfies: X = X h0 *ε+X e ; Wherein, ε is the calibration coefficient, ε=Δy / Δp; wherein, it is assumed that the displacement between images calculated by image measurement in the measurement system is Δp, and the actual displacement is Δy.

8. A linear motor rotor position measurement system, used in the linear motor rotor position measurement method according to any one of claims 1 to 7, characterized in that: The linear motor rotor position measurement system includes: A database module is used to build a multi-speed sample library based on the preset target shooting source and measurement system of the linear motor; A measurement cycle setting module, used to set a single measurement cycle of the mover position measurement according to the position loop frequency of the linear motor; wherein the single measurement cycle includes instantaneous speed measurement and mover position prediction; A captured image registration module, used for registering a reference image of a single measurement cycle according to the multi-speed sample library; An image acquisition module, used to acquire a target shooting source at a first acquisition frequency within a single measurement cycle to obtain i acquired images; wherein the first acquisition frequency is greater than the position loop frequency, and i is a natural number; The velocity measurement module is used to calculate the displacement between the acquired image and the reference image, and is used to infer the moving speed of the mover during the acquisition period and serve as the instantaneous speed of the mover; The mover position prediction module is used to estimate the mover position at the feedback moment according to the mover instantaneous speed and the reference image, and determine the actual mover displacement through the mover position at the feedback moment.

9. A computer device, characterized in that: The computer device includes a processor and a memory, wherein a computer program is stored in the memory. When the computer program is executed by the processor, the processor executes the steps of the linear motor mover position measurement method according to any one of claims 1 to 7.

10. 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 linear motor mover position measurement method according to any one of claims 1 to 7.

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