CN116819113A - Motor rotation speed measuring method and device, electronic equipment and storage medium - Google Patents

Abstract

The embodiment of the invention discloses a motor rotating speed measuring method, a device, electronic equipment and a storage medium, which relate to the technical field of online monitoring of generators, wherein a preset mark is arranged on the surface of a motor rotating shaft to be detected, a stroboscopic light source is controlled to project a light source to a motor to be detected according to a preset pulse period, and a camera is controlled to acquire a motor image in the process of projecting the light source to the motor to be detected; performing target detection on the motor image, determining the moving distance of a preset mark in the motor image, and determining the rotating speed of the motor to be detected based on the moving distance and a preset pulse period; according to the invention, the stroboscopic light source is controlled to stroboscopic by the pulse signal, the imaging picture acquired by the camera in the stroboscopic process is analyzed, and the measurement of the rotating speed of the generator is realized by utilizing the pixel moving range of the preset mark in the analysis picture and the preset pulse period, so that the problem of inaccurate rotating speed measurement caused by inconsistent tooth pitch of the fluted disc is avoided.

Description

Motor speed measurement method, device, electronic equipment and storage medium

Technical field

The invention relates to the technical field of generator online monitoring, and in particular to a motor speed measurement method, device, electronic equipment and storage medium.

Background technique

When the generator set is running, it is necessary to detect the rotation speed of the motor in the generator set and determine the operating status of the generator set.

The existing speed measurement method of the generator set is mainly to measure the speed through a toothed disc. By installing an annular toothed device at the end of the rotating shaft of the generator, and installing a toothed disc speed sensor and a corresponding speed signal processor on the fixed component, when When the unit rotates, a proximity or photoelectric sensor senses a pulse signal that reflects the unit's rotational speed. The host computer processes the pulse signal, measures the pulse width, and calculates the unit's rotational speed.

However, due to limitations in machining accuracy, the distance between the teeth on the gear disc (i.e., the tooth pitch) cannot be completely equal, and a highly sensitive sensor calculates the speed by scanning the time between teeth. That is to say, the speed of the unit may not change, but the calculated speed changes due to the change in tooth pitch, resulting in interference signals, thereby reducing the accuracy of the measurement results.

Contents of the invention

Embodiments of the present invention provide a motor speed measurement method, device, electronic equipment and storage medium to improve the accuracy of generator speed measurement.

On the one hand, embodiments of the present invention provide a method for measuring motor speed, which method includes:

Control the stroboscopic light source to project the light source to the motor to be tested according to a preset pulse period, and control the camera to collect the motor image during the process of projecting the light source to the motor to be tested; the surface of the rotating shaft of the motor to be detected is provided with a preset mark;

Perform target detection on the motor image and determine the movement distance of the preset mark in the motor image;

Based on the movement distance and the preset pulse period, the rotation speed of the motor under test is determined.

On the other hand, an embodiment of the present invention provides a motor speed measuring device, which includes:

The image acquisition module is used to control the stroboscopic light source to project the light source to the motor to be tested according to a preset pulse period, and to control the camera to collect the motor image during the process of projecting the light source to the motor to be tested; the surface of the rotating shaft of the motor to be detected is provided with default mark;

A distance detection module, used to perform target detection on the motor image and determine the movement distance of the preset mark in the motor image;

A rotational speed measurement module, configured to determine the rotational speed of the motor to be tested based on the movement distance and the preset pulse period.

On the other hand, an embodiment of the present invention provides an electronic device, including a memory and a processor; the memory stores an application program, and the processor is used to run the application program in the memory to perform the above motor speed measurement method. operation.

On the other hand, embodiments of the present invention provide a storage medium that stores a plurality of instructions, and the instructions are suitable for loading by a processor to execute the steps in the above motor speed measurement method.

Embodiments of the present invention provide a motor speed measurement method, device, electronic equipment and storage medium, which relate to the technical field of generator online monitoring. By controlling the stroboscopic light source to project the light source to the motor to be measured according to a preset pulse period, the camera is controlled to collect the direction. The motor image during the process of projecting a light source on the motor to be tested; a preset mark is set on the surface of the motor shaft to be detected, target detection is performed on the motor image, and the movement distance of the preset mark in the motor image is determined based on the movement distance and the preset pulse period. , determine the rotation speed of the motor to be tested; the present invention controls the strobe light source to strobe through pulse signals, analyzes the imaging pictures collected by the camera during the strobe process, and uses the pixel movement range of the preset markers in the analyzed pictures and the preset pulse period , realize the measurement of generator speed, and avoid the problem of inaccurate speed measurement caused by inconsistent tooth pitch of the tooth plate.

Description of the drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

Figure 1 is a schematic structural diagram of a motor speed measurement system provided by an embodiment of the present invention;

Figure 2 is a schematic flow chart of a motor speed measurement method provided by an embodiment of the present invention;

Figure 3 is a schematic diagram of the shutter exposure time of the camera and the pulse period of the stroboscopic light source provided by the embodiment of the present invention;

Figure 4 is a schematic flowchart of a method for detecting the movement distance of a preset mark provided by an embodiment of the present invention;

Figure 5 is a schematic flow chart of another motor speed measurement method provided by an embodiment of the present invention;

Figure 6 is a schematic structural diagram of a motor speed measuring device provided by an embodiment of the present invention;

Figure 7 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention.

Detailed ways

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concepts of the example embodiments. To those skilled in the art.

Furthermore, the described features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of embodiments of the invention. However, those skilled in the art will appreciate that the technical solutions of the present invention may be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other instances, well-known methods, apparatus, implementations, or operations have not been shown or described in detail to avoid obscuring aspects of the present invention.

The block diagrams shown in the figures are functional entities only and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and/or processor devices and/or microcontroller devices. entity.

The flowcharts shown in the drawings are only illustrative, and do not necessarily include all contents and operations/steps, nor must they be performed in the order described. For example, some operations/steps can be decomposed, and some operations/steps can be merged or partially merged, so the actual order of execution may change according to the actual situation.

It should be noted that the "multiple" mentioned in this article refers to two or more. "And/or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and/or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the related objects are in an "or" relationship.

As mentioned in the background art, due to the limitation of machining accuracy, the distance between the teeth on the gear disc (i.e., the tooth pitch) cannot be completely equal, and a highly sensitive sensor calculates the speed by scanning the time between teeth. of. That is to say, the speed of the unit may not change, but the calculated speed changes due to the change in tooth pitch, resulting in an interference signal, which will reduce the measurement results of the speed measurement method based on the gear disc; and because the gear disc speed measurement sensor has a "perception boundary point" ", and the generator may happen to be at the sensor's "critical point of sensing" when it is stopped. Due to the vibration of the generator set and the factory building, the speed sensor may sense the toothed disc, causing a false alarm, which will further reduce the speed measurement results. The accuracy; and the speed measurement method based on the gear disc requires adding gear disc equipment to the rotating parts, which increases the complexity of the system. At the same time, adding equipment to the rotating parts brings certain safety risks; in addition, in the end, due to the sensor's measurement The temperature range is limited, and the sensor installed on the fixed component is usually only 1-2mm away from the toothed disc. It is easy for dynamic and static components to rub against each other, causing damage to the equipment. The equipment needs to be replaced, which increases hardware costs. It can be seen that the existing speed measurement method based on the toothed disc has problems such as inaccurate measurement results, complex measurement, high hardware cost, and potential safety hazards.

Based on this, in order to improve the accuracy of the generator's rotational speed measurement results, reduce the cost of measurement hardware, and provide a convenient and safe rotational speed measurement method, embodiments of the present invention provide a motor rotational speed measurement method, device, electronic equipment and storage The medium controls the strobe light source to strobe through pulse signals, analyzes the imaging pictures collected by the camera during the strobe process, and uses the pixel movement range of the preset markers in the analyzed pictures and the preset pulse period to measure the generator speed. It avoids the problem of inaccurate rotation speed measurement caused by inconsistent tooth pitch of the tooth plate; and does not need to add structural parts to the rotating parts of the generator, reducing the complexity of the system and eliminating the safety risks caused by adding structural parts to the rotating parts. , In addition, the camera and the rotating shaft can be kept at a large distance, eliminating the risk of collision of dynamic and static components in the measurement method.

In order to facilitate understanding of the technical solutions provided by the embodiments of the present invention, the motor speed measurement method, device, electronic device and storage medium provided by the embodiments of the present invention will be introduced below in conjunction with specific application scenarios.

As shown in Figure 1, Figure 1 is a schematic structural diagram of a motor speed measurement system provided by an embodiment of the present invention. The motor speed measurement system shown includes a motor to be measured, a camera, a host computer, a pulse generator and a dispersive light source. The camera may be an area scan camera, such as an industrial camera.

Among them, the host computer is connected to the camera and the pulse generator respectively, and is used to send instructions to the camera so that the camera collects the motor image of the motor to be tested, and sends instructions to the pulse generator to control the pulse generator to send pulses to the stroboscopic light source. The stroboscopic light source projects the light source to the motor under test according to the preset pulse period, and is used to receive the motor image collected by the camera, perform target detection on the motor image, and determine the moving distance of the preset mark in the motor image. Based on the moving distance and the preset Set the pulse period to determine the speed of the motor under test.

In some embodiments, preset marks are provided on the surface of the rotating shaft of the motor to be tested. As shown in FIG. 1 , diagonal stripes are provided on the surface of the rotating shaft of the motor to be tested. It should be noted that the preset marks shown in FIG. 1 are only illustrative and do not limit the embodiments of the present invention. The preset marks may also be in shapes such as vertical stripes, circles, triangles, etc.

Optionally, preset marks can be set on the surface of the rotating shaft of the motor to be tested by spraying, printing, pasting, etc.

It can be understood that the pulse generator sends a pulse signal to the stroboscopic light source based on the preset pulse period, and the stroboscopic light source projects the light source to the motor under test according to the pulse signal. Since the stroboscopic light source intermittently projects the light source to the motor under test, in During the period when the stroboscopic light source does not project light onto the motor under test, there is no light source in the environment where the motor under test is located, and the camera cannot capture the preset mark on the surface of the rotating shaft. When the stroboscopic light source projects light onto the motor under test, The camera captures the preset mark on the surface of the rotating shaft. In the process of projecting the light source to the motor under test through the stroboscopic light source according to the pulse signal, the movement of the rotating shaft causes the preset mark on the surface of the rotating shaft to rotate. Since the camera has a shutter exposure time, when the preset When the stroboscopic light source is projected to the motor under test during the pulse period, the camera captures the moving distance of the preset mark on the surface of the rotating shaft within the preset pulse period, and then can based on the movement distance of the preset mark on the surface of the rotating shaft within the preset pulse period. The moving distance is the speed of the motor under test. For example, when a stroboscopic light source projects two light sources to the motor under test within a preset pulse period, due to the time difference between the projection times of the two light sources, the movement of the rotating shaft within this time difference causes the rotation of the preset mark on the surface of the rotating shaft. In the motor image captured by the camera, there are two preset marks. By calculating the distance between the two preset marks, the moving distance of the preset marks in the motor image can be determined, and then the rotation speed of the motor to be measured can be determined.

In some embodiments, as shown in Figure 1, the host computer includes a database, a rotation speed calculation unit, and a camera and light source control unit. The rotation speed calculation unit is connected to the data, and the rotation speed calculation unit is used to receive the motor data collected by the camera. Image, perform target detection on the motor image, determine the moving distance of the preset mark in the motor image, determine the rotational speed of the motor to be tested based on the moving distance and the preset pulse period, and write the rotational speed of the motor to be tested into the database; camera and light source The control unit is used to send control instructions to the area scan camera and to the pulse generator.

The motor speed measurement system provided by the embodiment of the present invention uses pulse signals to control the strobe light source to strobe, analyzes the imaging pictures collected by the camera during the strobe process, and analyzes the pixel movement range of the preset markers in the pictures and the preset pulses. period, to achieve the measurement of generator speed, avoiding the problem of inaccurate speed measurement caused by inconsistent tooth pitch of the tooth plate; and there is no need to add structural parts to the rotating parts of the generator, which reduces the complexity of the system and eliminates the need to Components increase the safety risks caused by structural parts. In addition, the camera and the rotating shaft can be kept at a large distance, eliminating the risk of collision of dynamic and static components in the measurement method.

Based on the motor speed measurement system shown in Figure 1, an embodiment of the present invention provides a motor speed measurement method, as shown in Figure 2. Figure 2 is a schematic flow chart of the motor speed measurement method provided by an embodiment of the present invention. The motor shown The rotation speed measurement method can be applied to the host computer in the motor rotation speed measurement system shown in Figure 1, or to computer equipment with data processing capabilities, such as industrial computers, servers, etc. This is not specifically limited in the embodiment of the present invention. Specifically, the motor speed measurement method shown at least includes steps 210 to 230, which are described in detail as follows:

Step 210: Control the stroboscopic light source to project the light source to the motor to be tested according to a preset pulse period, and control the camera to collect images of the motor during the process of projecting the light source to the motor to be tested.

Among them, preset marks are provided on the surface of the motor shaft to be detected.

In some embodiments, the preset pulse period can be preset by the operator.

In some embodiments, the camera has a shutter exposure time. In order to ensure that the camera can capture the position information of the preset marks set on the surface of the motor shaft to be tested at different times during the shutter exposure time, it is necessary to ensure that within the shutter exposure time, the frequency The flash source can project the light source to the motor under test at least twice. Based on this, the preset pulse period can be determined according to the shutter exposure time of the camera.

Optionally, send a shooting instruction to the camera, determine a preset pulse period based on the camera's shutter exposure time, generate a pulse signal based on the preset pulse period, send the pulse signal to the stroboscopic light source, and the stroboscopic light source triggers the light source based on the pulse signal. The camera opens and closes to project a light source to the motor to be tested, and the camera responds to the shooting instructions to collect images of the motor during the process of projecting the light source to the motor to be tested.

In some embodiments, in order to ensure that the collected motor images can record the position information of the preset markers at different times, the camera can be controlled to continuously shoot according to the preset frame rate and shutter exposure time, and the camera can be controlled during the continuous shooting process. In the method, the stroboscopic light source is controlled to project the light source to the motor under test according to a preset pulse period. This can ensure that among the multiple motor images collected by the camera, there is at least one motor image that records the position information of the preset mark at different times.

Optionally, shooting instructions can be sent to the camera at preset intervals. At the same time, the preset pulse period is determined based on the shutter exposure time of the camera, a pulse signal is generated based on the preset pulse period, and the pulse signal is sent to the stroboscopic light source. The source triggers the opening and closing of the light source based on the pulse signal, and projects the light source to the motor to be tested. The camera responds to the shooting instructions and determines the camera frame rate, shutter exposure time and shooting duration. The camera performs operations according to the camera frame rate and shutter exposure time within the shooting duration. Shoot continuously to obtain multiple motor images.

Step 220: Perform target detection on the motor image to determine the movement distance of the preset mark in the motor image.

In some implementations, target detection can be performed on the motor image through a preset detection model to obtain the movement distance of the preset mark in the motor image. Among them, the detection model can be a detection model based on machine learning, such as a detection model based on dictionary learning, or a detection model based on a neural network, such as a detection model based on CNN, a detection model based on Fast-cnn, or a detection model based on Faster-cnn. detection model, or a detection model based on YOLO.

In some implementations, target detection can be performed on the motor image, preset marks at different positions in the motor image are determined, and the movement distance of the preset mark in the motor image is obtained based on the pixel distance between the preset marks. The pixel distance may be the distance between the preset marks in the image coordinate system where the motor image is located, and the pixel distance may also be the number of pixels between the preset marks in the motor image.

Optionally, target detection can be performed on the motor image through a preset detection model; optionally, target detection can also be performed on the motor image through an edge detection operator.

In some embodiments, target detection can be performed on the motor image to determine whether there are at least two preset marks in the motor image. If there are at least two preset marks, determine the image area where each preset mark in the motor image is located. , based on the position information of the image area where each preset mark is located, the moving distance of the preset mark in the motor image is obtained; if there are not at least two preset marks, the motor image is discarded and the next motor image is targeted. , or re-acquire motor images.

In some embodiments, the motor image and the pre-stored reference image can be differentiated to obtain a difference image between the motor image and the pre-stored reference image, target detection is performed based on the difference image, and the image area where the preset mark is located in the difference image is determined. , based on the position information of the image area where each preset mark is located, the movement distance of the preset mark in the motor image is obtained. The preset reference image may be an image without a preset mark.

Step 230: Determine the rotation speed of the motor to be tested based on the movement distance and the preset pulse period.

In some embodiments, after the moving distance is determined, the rotational speed of the motor to be measured can be obtained based on the moving distance and the preset pulse period, using the moving distance/preset pulse period.

In some embodiments, after determining the moving distance, the linear speed of the motor to be tested can be obtained based on the moving distance and the preset pulse period. According to the moving distance/preset pulse period, the linear speed of the motor to be tested can be obtained. According to the radius of the rotating shaft of the motor to be detected and Linear speed, the speed of the motor under test is obtained through 120*π*shaft radius*linear speed.

In some embodiments, after the moving distance is determined, the linear speed of the motor to be tested can be obtained based on the moving distance and the preset pulse period, by moving distance/preset pulse period, based on the preset speed of the motor to be tested. The mapping relationship between linear speed and rotational speed is used to obtain the rotational speed of the motor under test. The preset mapping relationship between the linear speed and the rotation speed of the motor to be detected is used to indicate the mapping relationship between the linear speed and the corresponding rotation speed of the motor to be detected.

In some implementations, if there are multiple motor images, the initial rotation speed corresponding to the motor image can be obtained based on the movement distance of the preset mark in each motor image, and the initial rotation speed corresponding to each motor image can be averaged to obtain the target value. Measure the rotation speed of the motor; if there is a motor image, determine the initial rotation speed corresponding to the motor image as the rotation speed of the motor to be measured.

In some embodiments, the above-mentioned steps 210 to 230 can be performed at preset intervals within a period of time to obtain the rotation speed sequence of the motor to be tested. Based on the rotation speed sequence of the motor to be tested, the rotation state of the motor to be tested is detected, and the rotation status of the motor to be tested is determined. Whether there is any abnormality in the rotation state of the motor, and when there is any abnormality in the rotation state of the motor to be tested, a warning message will be issued to prompt the staff to perform maintenance on the motor to be tested. Among them, the rotation state includes abnormal rotation and normal rotation.

For example, when there are rotation speeds in the rotation speed sequence of the motor under test that are continuously greater than the preset rotation speed threshold, it is determined that the rotation of the motor under test is abnormal. When the rotation speeds in the rotation speed sequence of the motor under test are all less than or equal to the preset rotation speed threshold, it is determined that the rotation speed of the motor under test is abnormal. The motor under test rotates normally.

The motor speed measurement method provided by the embodiment of the present invention uses pulse signals to control the strobe light source to strobe, analyzes the imaging pictures collected by the camera during the strobe process, and uses the pixel movement range of the preset markers in the analyzed pictures and the preset pulses to period, to achieve the measurement of generator speed, avoiding the problem of inaccurate speed measurement caused by inconsistent tooth pitch of the tooth plate; and there is no need to add structural parts to the rotating parts of the generator, which reduces the complexity of the system and eliminates the need to Components increase the safety risks caused by structural parts. In addition, the camera and the rotating shaft can be kept at a large distance, eliminating the risk of collision of dynamic and static components in the measurement method.

Considering that the camera has a shutter exposure time, in order to ensure that the camera captures the same motor image at the positions of preset marks at different times, it is necessary to ensure that the stroboscopic light source projects the light source to the motor at least twice during the shutter exposure time. Based on this, In some embodiments, the pulse period can be set according to the shutter exposure time of the camera and the number of strobes of the strobe light source. Specifically, the method for determining the pulse period includes steps a1 to a2:

Step a1: Obtain the shutter exposure time of the camera and the number of stroboscopic flashes of the stroboscopic light source within the shutter exposure time.

Step a2: Determine the preset pulse period of the stroboscopic light source based on the shutter exposure time and the number of stroboscopic flashes.

In some embodiments, the shutter exposure time of the camera and the number of stroboscopic flashes of the stroboscopic light source input by the staff based on the configuration page view can be obtained.

In some implementations, the shutter exposure time of the camera and the number of stroboscopic flashes of the stroboscopic light source sent by the background server can be obtained.

In some embodiments, the preset pulse period of the stroboscopic light source can be obtained based on the shutter exposure time and the number of stroboscopic flashes, by using the shutter exposure time/number of stroboscopic flashes.

For example, the number of stroboscopic flashes of the stroboscopic light source within the shutter exposure time is 2. As shown in Figure 3, Figure 3 shows the shutter exposure time of the camera and the pulse period of the stroboscopic light source provided by the embodiment of the present invention. The schematic diagram of Triggering two pulse signals within a shutter exposure time t, the pulse mid-cycle between pulse signals is T=t/2, each pulse lasts for T1 time, where K is the frame rate of the camera, 1/K is the shooting frequency of the camera.

The embodiment of the present invention determines the preset pulse period of the stroboscopic light source through the shutter exposure time and the number of stroboscopic flashes, ensuring that the stroboscopic light source can project the number of stroboscopic light sources to the motor under test within the shutter exposure time. Since the stroboscopic light source each There is a time difference between the light sources projected onto the motor to be tested, and the motor to be detected operates sequentially. Therefore, the motor can capture the position changes of the preset mark set on the surface of the motor shaft to be detected within the time difference, thereby determining the preset value in the motor image. The distance the marker moves.

Considering that the motor continues to rotate during the shutter exposure time, there may be multiple preset marks in the motor image collected by the camera, and each preset mark has a different position in the motor image. By detecting the outlines of multiple preset marks The distance between them is the moving distance of the preset mark. Based on this, in some embodiments, edge detection can be performed on the motor image, the outline of each preset mark in the motor image is determined, and the preset mark in the motor image is determined based on the distance between the outlines of each preset mark in the motor image. The distance the marker moves.

Optionally, edge detection can be performed on the motor image through an edge detection operator to determine the outline of each preset mark in the motor image. Among them, edge detection operators include but are not limited to gradient operators, Sobel (Chinese: discrete differential operator), Roberts (Chinese: oblique deviation gradient calculation method, Prewitt (edge detection operator of differential operators), Canny (Chinese: optimal ladder-type edge detection operator) and Laplacian (Chinese: second-order differential operator) edge identification operator.

Wherein, the distance between the outlines of each preset mark in the motor image may be the distance between the outer edges of the outlines of each preset mark in the motor image; it may also be the distance between the outer edges of the outlines of each preset mark in the motor image. The distance between inner edges; can also be the distance between the center points of each preset marked outline in the motor image.

In some implementations, the distance between the outlines of each preset mark in the motor image may be determined as the movement distance of the preset mark in the motor image.

In some embodiments, the movement distance of the preset mark in the motor image can be obtained based on the distance between the outlines of each preset mark in the motor image and the mapping relationship between the preset image distance and the actual distance.

The preset mapping relationship between the image distance and the actual distance is used to indicate the mapping relationship between the image distance and the actual distance in the corresponding actual coordinate system. In some implementations, the preset mapping relationship between the image distance and the actual distance may be a mapping function between the image distance and the actual distance, such as a conversion function between the image coordinate system and the world coordinate system.

Optionally, when there are two preset marks in the motor image, the movement distance of the preset marks in the motor image can be obtained based on the distance between the outlines of the preset marks.

Optionally, when there are more than two preset marks in the motor image, the maximum distance between the outlines of each preset mark in the motor image can be determined as the target outline distance, and the target outline distance in the motor image can be obtained based on the target outline distance. The moving distance of the preset mark, for example, determine the target contour distance as the moving distance of the preset mark in the motor image; for example, according to the target contour distance and the mapping relationship between the preset image distance and the actual distance, obtain the moving distance of the preset mark in the motor image. Default marker movement distance.

In order to improve the accuracy of edge detection and thereby improve the accuracy of the movement distance of the preset mark in the motor image, thereby ensuring the credibility of the rotation speed measurement results, in some implementations, the motor image can be preprocessed. Based on the preprocessing Edge detection is performed on the final motor image. In this way, by improving the image quality of the motor image, the accuracy of edge detection is improved, thereby improving the accuracy of the movement distance of the preset mark in the motor image, thereby ensuring the credibility of the speed measurement results. Among them, preprocessing includes but is not limited to image sharpening, grayscale stretching, image noise reduction, image edge enhancement, etc.

Specifically, as shown in Figure 4, Figure 4 is a schematic flowchart of a method for detecting the movement distance of a preset mark provided by an embodiment of the present invention. The method shown for detecting the movement distance of a preset mark includes steps 221 to 223:

Step 221: Preprocess the motor image to obtain a preprocessed motor image.

Step 222: Perform edge detection on the preprocessed motor image to determine the outline of each preset mark in the preprocessed motor image.

Step 223: Determine the pixel distance between each contour, and determine the movement distance of the preset mark in the preprocessed motor image based on the pixel distance between each contour.

In some embodiments, based on the outline of each preset mark, the image coordinates of the center point of the outline of each preset mark in the image coordinate system where the motor image is located can be determined, based on the center point of the outline of each preset mark The distance between the image coordinates is used to obtain the pixel distance between each contour. For example, based on the image coordinates of the center points of the contours of each preset mark, the Euclidean distance or the Mahalanobis distance between the image coordinates of the center points of the contours of each preset mark may be determined as the pixel distance between the contours. Among them, the center point can be the geometric center point or the center of gravity point.

In some embodiments, based on the outline of each preset mark, the image coordinates of the edge of the outline of each preset mark in the image coordinate system where the motor image is located can be determined, and based on the edge of the outline of each preset mark in the motor The image coordinates in the image coordinate system where the image is located determine the pixel distance between the outlines of each preset mark. The edge can be an outer edge or an inner edge.

In some implementations, the pixel distance between the contours of each preset mark can also be obtained based on the image coordinates of the preset key points in each contour in the image coordinate system where the motor image is located. Among them, the preset key point can be the center point of the contour, the center point of the edge in the contour, or any point in the contour.

In some implementations, the pixel distance between the contours of each preset mark can also be determined based on the number of pixels between the preset key points in each contour. Specifically, the method for determining the pixel distance includes:

(1) According to the position information of the preset key points in each outline, determine the number of pixels between the preset key points in each outline.

(2) Determine the number of pixels between the preset key points in each contour as the pixel distance between each contour.

Optionally, the position information of the preset key points in each outline in the motor image can be compared to obtain the image length between the preset key points in each outline, based on the image between the preset key points in each outline. The length and the resolution of the motor image are used to obtain the number of pixels between preset key points in each contour.

Optionally, the number of pixels between the position information of the preset key points in the motor image in each contour and the position information of the preset key points in the motor image in other contours can be counted to obtain the preset key points in each contour. The number of pixels between points.

In some embodiments, after determining the pixel distance, the pixel distance can be mapped to the world coordinate system based on the mapping relationship between the image coordinate system and the world coordinate system to obtain the movement of the preset mark in the preprocessed motor image. distance. The mapping relationship between the image coordinate system and the world coordinate system is used to indicate the mapping relationship between the coordinate values in the image coordinate system and the coordinate values in the world coordinate system.

In some embodiments, after determining the pixel distance, in order to ensure the accuracy of the movement distance calculation, it is also necessary to consider the actual physical size represented by each pixel in the motor image, and then determine the preprocessed mark in the motor image. The moving distance requires the camera's preset pixel accuracy and pixel distance to determine the moving distance of the preset mark in the preprocessed motor image. The camera's preset pixel accuracy is used to characterize each pixel in the image captured by the camera. actual physical size. Specifically, the moving distance determination method based on pixel distance includes:

(1) Based on the pixel distance between each contour and the preset pixel accuracy of the camera, the initial movement distance of the preset mark in the preprocessed motor image is obtained.

(2) According to the image height of the preset mark in the preprocessed motor image and the preset actual height of the preset mark, the correction coefficient between the pixel length and the actual distance is obtained.

(3) Correct the initial movement distance based on the correction coefficient to obtain the movement distance of the preset mark in the preprocessed motor image.

In some implementations, the initial movement distance of the preset mark in the preprocessed motor image can be obtained based on the pixel distance between the contours and the preset pixel accuracy of the camera, using the pixel distance * the preset pixel accuracy.

In some implementations, the physical distance between the contours can be obtained based on the pixel distance between the contours and the preset pixel precision of the camera, and the physical distance between the contours is calculated by pixel distance * preset pixel precision. The farthest distance is determined as the initial movement distance of the preset mark in the preprocessed motor image.

Among them, the correction coefficient is used to indicate the mapping coefficient between the length in the image coordinate system and the length in the world coordinate system. In some embodiments, the image height of the preset mark and the preset actual height of the preset mark in the preprocessed motor image can be used to obtain the correction coefficient through the image height/preset actual height. Among them, the image height represents the height of the preset mark in the image coordinate system where the motor image is located.

In some implementations, based on the correction coefficient, the movement distance of the preset mark in the preprocessed motor image can be obtained by the correction coefficient*initial movement distance.

In some embodiments, after obtaining the movement distance of the preset mark in the preprocessed motor image, the rotation speed of the motor to be tested may be determined according to the method for determining the rotation speed of the motor to be tested in step 230.

Considering that due to factory vibration or inertial movement after the motor is shut down, or when the motor is running at low speed, the motor shaft will move at a low speed, it may be difficult to capture the position change of the preset mark during the shutter exposure time of the camera, or the position of the preset mark. The position change is small. Therefore, if the camera uses the same shutter exposure time for image acquisition, there may be a problem of inaccurate calculation of the moving distance, thereby reducing the accuracy of the rotational speed measurement results. Based on this, in order to ensure the accuracy of the rotation speed measurement results, in some embodiments, after obtaining the moving distance, the moving distance is compared with a preset distance threshold. When the moving distance is less than or equal to the preset distance threshold, the camera shutter is The exposure time is adjusted to ensure that the position changes of the preset mark can be captured within the camera's shutter exposure time. Specifically, as shown in Figure 5, Figure 5 is a schematic flow chart of another motor speed measurement method provided by an embodiment of the present invention. The motor speed measurement method shown at least includes steps 510 to 580:

Step 510: Control the stroboscopic light source to project the light source to the motor to be tested according to a preset pulse period, and control the camera to collect images of the motor during the process of projecting the light source to the motor to be tested.

In some embodiments, step 210 of the motor speed measurement method provided in Figure 2 can be referred to, the stroboscopic light source is controlled to project the light source to the motor to be tested according to the preset pulse period, and the camera is controlled to collect the motor during the process of projecting the light source to the motor to be tested. Image, the embodiment of the present invention will not be described in detail here.

In some embodiments, the preset pulse period can be determined according to the pulse period determination method provided in steps a1 to a2. Refer to step 210 in the motor speed measurement method provided in Figure 2 to control the stroboscopic light source according to the preset pulse period. Project a light source to the motor to be tested, and control the camera to collect the image of the motor during the process of projecting the light source to the motor to be tested. The embodiments of the present invention will not be described in detail here.

Step 520: Perform target detection on the motor image to determine the movement distance of the preset mark in the motor image.

In some embodiments, the movement distance of the preset mark in the motor image can be determined with reference to the detection method of the movement distance of the preset mark provided in FIG. 4 , which will not be described in detail here in the embodiment of the present invention.

Step 530: If the moving distance is greater than the preset distance threshold, determine the rotational speed of the motor to be tested based on the moving distance and the preset pulse period.

In some embodiments, the movement distance can be compared with the preset distance threshold. If the movement distance is greater than the preset distance threshold, the speed of the motor to be measured is determined according to step 230 of the motor speed measurement method provided in Figure 2. The present invention implements The example will not be repeated here.

Step 540: If the movement distance is less than or equal to the preset distance threshold, adjust the shutter exposure time of the camera and adjust the pulse period.

In some embodiments, if the movement distance is less than or equal to the preset distance threshold, the adjustment coefficient is obtained, and the shutter exposure time of the camera is adjusted based on the adjustment coefficient. Based on the adjusted shutter exposure time and the number of stroboscopic flashes of the stroboscopic light source, The adjusted pulse period is obtained through the adjusted shutter exposure time/number of stroboscopic flashes of the strobe light source. Among them, the adjustment coefficient is an integer greater than 1.

Optionally, you can obtain the adjusted shutter exposure time by adjusting the coefficient * the shutter exposure time of the camera.

Optionally, you can get the adjusted shutter exposure time by using the camera's shutter exposure time*2^ (adjustment coefficient).

Optionally, the adjustment coefficient can be obtained from a preset adjustment coefficient sequence; optionally, the adjustment coefficient input by the staff can be obtained; optionally, the number of adjustments to the shutter exposure time can be obtained, and the number of adjustments can be determined as the adjustment coefficient. , or determine 2^ (number of adjustments) as the adjustment coefficient.

Step 550: Project a light source to the motor under test based on the adjusted pulse period, and control the camera to collect a new motor image during the process of projecting the light source onto the motor under test according to the adjusted shutter exposure time.

In some embodiments, step 210 of the motor speed measurement method provided in Figure 2 can be used to project a light source to the motor under test based on the adjusted pulse period, and control the camera to collect the light source projected from the motor under test according to the adjusted shutter exposure time. The new motor image will not be described again in the embodiment of the present invention.

Step 560: Perform target detection on the new motor image to determine the new moving distance of the preset mark in the motor image.

In some embodiments, the new movement distance of the preset mark in the motor image can be determined with reference to the detection method of the movement distance of the preset mark provided in FIG. 4 , which will not be described in detail here in the embodiment of the present invention.

Step 570: If the new movement distance is less than or equal to the preset distance threshold, the preset rotation speed is determined as the rotation speed of the motor to be tested.

In some embodiments, if the new movement distance is less than or equal to the preset distance threshold, then steps 540 to 560 are repeated to obtain the new movement distance. If the new movement distance is less than or equal to the preset distance threshold, the motor shaft to be tested is If there is no speed or the speed is too low, the set speed will be determined as the speed of the motor under test. Among them, the preset rotation speed can be 0/s.

In some embodiments, if the new movement distance is less than or equal to the preset distance threshold, and the number of shutter exposure time adjustments is greater than the preset number threshold, then the set rotation speed is determined as the rotation speed of the motor to be tested; if the number of shutter exposure time adjustments is less than or equal to the preset times threshold, then steps 540 to 560 are repeated to obtain a new moving distance.

Step 580. After step 560, if the new moving distance is greater than the preset distance threshold, the rotation speed of the motor to be tested is determined based on the new moving distance and the adjusted pulse period.

In some embodiments, if the new movement distance is greater than the preset distance threshold, the rotation speed of the motor to be measured is determined according to step 230 of the motor rotation speed measurement method provided in Figure 2. This embodiment of the present invention will not be repeated here.

The motor speed measurement method provided by the embodiment of the present invention automatically controls the camera shutter exposure time by increasing the detection of the moving distance. When the rotation speed is too low or has no rotation speed, resulting in insufficient pixel accuracy and the moving distance cannot be accurately obtained, the camera shutter exposure time is increased. , to obtain the effective moving distance, so that the parameters of the camera, pulse generator and other equipment can match the current speed of the motor to be measured, to perform more accurate measurements and avoid inaccurate speed measurement results due to too low speed or factory vibration. .

In order to better implement the motor speed measurement method provided by the embodiment of the present invention, based on the embodiment of the motor speed measurement method, the embodiment of the present invention provides a motor speed measurement device, as shown in Figure 6. Figure 6 is an embodiment of the present invention The structural schematic diagram of the motor speed measurement device is provided. The motor speed measurement device shown includes:

The image acquisition module 601 is used to control the stroboscopic light source to project the light source to the motor to be tested according to a preset pulse period, and to control the camera to collect the motor image during the process of projecting the light source to the motor to be tested; the surface of the motor shaft to be detected is provided with preset marks. ;

The distance detection module 602 is used to perform target detection on the motor image and determine the movement distance of the preset mark in the motor image;

The rotation speed measurement module 603 is used to determine the rotation speed of the motor to be tested based on the movement distance and the preset pulse period.

In some implementations, the distance detection module 602 includes:

The image preprocessing unit is used to preprocess the motor image to obtain the preprocessed motor image;

An edge detection unit, used to perform edge detection on the preprocessed motor image and determine the outline of each preset mark in the preprocessed motor image;

The distance detection unit is used to determine the pixel distance between each contour, and determine the movement distance of the preset mark in the preprocessed motor image based on the pixel distance between each contour.

In some embodiments, the distance detection unit is used for:

Based on the pixel distance between each contour and the preset pixel accuracy of the camera, the initial movement distance of the preset mark in the preprocessed motor image is obtained;

According to the pixel height of the preset mark in the preprocessed motor image and the preset actual height of the preset mark, the correction coefficient between the pixel length and the actual distance is obtained;

The initial movement distance is corrected based on the correction coefficient to obtain the movement distance of the preset mark in the preprocessed motor image.

In some embodiments, the distance detection unit is used for:

Determine the number of pixels between the preset key points in each contour based on the position information of the preset key points in each contour;

The number of pixels between preset keypoints in each contour is determined as the pixel distance between each contour.

In some embodiments, the rotation speed measurement module 603 is used for:

According to the moving distance and the preset pulse period, the linear speed of the motor under test is obtained;

Get the shaft radius of the motor shaft to be detected;

According to the radius of the rotating shaft and the linear speed, the rotation speed of the motor under test is obtained.

In some embodiments, the motor speed measuring device further includes:

The feedback adjustment module 604 is used to adjust the shutter exposure time of the camera and adjust the pulse period if the movement distance is less than or equal to the preset distance threshold;

The image acquisition module 601 is used to project a light source to the motor to be tested based on the adjusted pulse period, and control the camera to collect a new motor image during the process of projecting the light source of the motor to be tested according to the adjusted shutter exposure time;

The distance detection module 602 is used to perform target detection on the new motor image and determine the new movement distance of the preset mark in the motor image;

The rotation speed measurement module 603 is used to determine the preset rotation speed as the rotation speed of the motor to be measured if the new movement distance is less than or equal to the preset distance threshold; if the new movement distance is greater than the preset distance threshold, determine the preset rotation speed based on the new movement distance. The distance and the adjusted pulse period determine the speed of the motor under test.

In some embodiments, the motor speed measuring device further includes:

The control module 605 is used to obtain the shutter exposure time of the camera and the number of stroboscopic flashes of the stroboscopic light source within the shutter exposure time; and determine the preset pulse period of the stroboscopic light source based on the shutter exposure time and the number of stroboscopic flashes.

The motor speed measuring device provided by the embodiment of the present invention controls the strobe light source to strobe through pulse signals, analyzes the imaging pictures collected by the camera during the strobe process, and analyzes the pixel movement range of the preset markers in the pictures and the preset pulses. period, to achieve the measurement of generator speed, avoiding the problem of inaccurate speed measurement caused by inconsistent tooth pitch of the tooth plate; and there is no need to add structural parts to the rotating parts of the generator, which reduces the complexity of the system and eliminates the need to Components increase the safety risks caused by structural parts. In addition, the camera and the rotating shaft can be kept at a large distance, eliminating the risk of collision of dynamic and static components in the measurement method.

An embodiment of the present invention also provides an electronic device, as shown in Figure 7, which shows a schematic structural diagram of the electronic device involved in the embodiment of the present invention. Specifically:

The electronic device may include components such as a processor 701 of one or more processing cores, a memory 702 of one or more computer-readable storage media, a power supply 703, and an input unit 704. Those skilled in the art can understand that the structure of the electronic device shown in FIG. 7 does not constitute a limitation of the electronic device, and may include more or fewer components than shown in the figure, or combine certain components, or arrange different components. in:

The processor 701 is the control center of the electronic device, using various interfaces and lines to connect various parts of the entire electronic device, by running or executing software programs and/or modules stored in the memory 702, and calling software programs stored in the memory 702. Data, perform various functions of the electronic device and process the data to conduct overall monitoring of the electronic device. Optionally, the processor 701 may include one or more processing cores; preferably, the processor 701 may integrate an application processor and a modem processor, where the application processor mainly processes operating systems, user interfaces, application programs, etc. , the modem processor mainly handles wireless communications. It can be understood that the above-mentioned modem processor may not be integrated into the processor 701.

The memory 702 can be used to store software programs and modules. The processor 701 executes various functional applications and data processing by running the software programs and modules stored in the memory 702 . The memory 702 may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the storage data area may store a program based on Data created by the use of electronic devices, etc. In addition, memory 702 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other volatile solid-state storage device. Accordingly, the memory 702 may also include a memory controller to provide the processor 701 with access to the memory 702 .

The electronic device also includes a power supply 703 that supplies power to various components. Preferably, the power supply 703 can be logically connected to the processor 701 through a power management system, so that functions such as charging, discharging, and power consumption management can be implemented through the power management system. Power supply 703 may also include one or more DC or AC power supplies, recharging systems, power failure detection circuits, power converters or inverters, power status indicators, and other arbitrary components.

The electronic device may also include an input unit 704 that may be used to receive input numeric or character information and generate keyboard, mouse, joystick, optical, or trackball signal input related to user settings and function control.

Although not shown, the electronic device may also include a display unit and the like, which will not be described again here. Specifically, in this embodiment, the processor 701 in the electronic device will load the executable files corresponding to the processes of one or more application programs into the memory 702 according to the following instructions, and the processor 701 will run the executable files stored in The application program in the memory 702 implements various functions, as follows:

The stroboscopic light source is controlled to project the light source to the motor to be tested according to a preset pulse period, and the camera is controlled to collect the motor image during the process of projecting the light source to the motor to be tested; a preset mark is set on the surface of the motor shaft to be detected;

Perform target detection on the motor image and determine the moving distance of the preset mark in the motor image;

Based on the moving distance and the preset pulse period, the rotation speed of the motor under test is determined.

Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructions, or by controlling relevant hardware through instructions. The instructions can be stored in a computer-readable storage medium, and loaded and executed by the processor.

To this end, embodiments of the present invention provide a storage medium in which a plurality of instructions are stored, and the instructions can be loaded by a processor to execute the steps in any motor speed measurement method provided by embodiments of the present invention. For example, this command can perform the following steps:

The stroboscopic light source is controlled to project the light source to the motor to be tested according to a preset pulse period, and the camera is controlled to collect the motor image during the process of projecting the light source to the motor to be tested; a preset mark is set on the surface of the motor shaft to be detected;

Perform target detection on the motor image and determine the moving distance of the preset mark in the motor image;

Based on the moving distance and the preset pulse period, the rotation speed of the motor under test is determined.

For the specific implementation of each of the above operations, please refer to the previous embodiments and will not be described again here.

The storage medium may include: read only memory (ROM, Read Only Memory), random access memory (RAM, Random Access Memory), magnetic disk or optical disk, etc.

Since the instructions stored in the storage medium can execute the steps in any motor speed measurement method provided by the embodiment of the present invention, therefore, any of the motor speed measurement methods provided by the embodiment of the present invention can be realized. The beneficial effects achieved are detailed in the previous embodiments and will not be described again here.

The above is a detailed introduction to a motor speed measurement method, device, electronic equipment and storage medium provided by the embodiments of the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments It is only used to help understand the method and its core idea of the present invention; at the same time, for those skilled in the art, there will be changes in the specific implementation and application scope according to the idea of the present invention. In summary, this The content of the description should not be construed as limiting the invention.

Claims (10)

1. A method of measuring rotational speed of an electric motor, the method comprising:

the method comprises the steps of controlling a stroboscopic light source to project a light source to a motor to be tested according to a preset pulse period, and controlling a camera to acquire a motor image in the process of projecting the light source to the motor to be tested; the surface of the motor rotating shaft to be detected is provided with a preset mark;

performing target detection on the motor image, and determining the moving distance of a preset mark in the motor image;

and determining the rotating speed of the motor to be tested based on the moving distance and the preset pulse period.

2. The method for measuring a rotational speed of a motor according to claim 1, wherein the performing object detection on the motor image to determine a moving distance of a preset mark in the motor image includes:

Preprocessing the motor image to obtain a preprocessed motor image;

performing edge detection on the preprocessed motor image, and determining the outline of each preset mark in the preprocessed motor image;

and determining the pixel distance between the outlines, and determining the moving distance of a preset mark in the preprocessed motor image based on the pixel distance between the outlines.

3. The motor rotation speed measurement method according to claim 2, wherein the determining a movement distance of a preset mark in the preprocessed motor image based on a pixel distance between the contours includes:

obtaining an initial moving distance of a preset mark in the preprocessed motor image based on a pixel distance between the outlines and a preset pixel precision of the camera;

obtaining a correction coefficient between the pixel length and the actual distance according to the pixel height of a preset mark in the preprocessed motor image and the preset actual height of the preset mark;

and correcting the initial moving distance based on the correction coefficient to obtain the moving distance of the preset mark in the preprocessed motor image.

4. The motor speed measurement method according to claim 2, wherein the determining the pixel distance between the profiles includes:

determining the number of pixels between preset key points in each contour according to the position information of the preset key points in each contour;

and determining the number of pixels between preset key points in each contour as the pixel distance between the contours.

5. The motor rotation speed measurement method according to claim 1, wherein the determining the rotation speed of the motor to be measured based on the moving distance and the preset pulse period includes:

obtaining the linear speed of the motor to be tested according to the moving distance and the preset pulse period;

acquiring the radius of a rotating shaft of the motor to be detected;

and obtaining the rotating speed of the motor to be tested according to the radius of the rotating shaft and the linear speed.

6. The motor speed measurement method according to claim 1, wherein after the target detection is performed on the motor image and the moving distance of the preset mark in the motor image is determined, the method further comprises:

if the moving distance is smaller than or equal to a preset distance threshold value, adjusting shutter exposure time of the camera and adjusting the pulse period;

Based on the adjusted pulse period, projecting a light source to the motor to be detected, controlling the camera to acquire a new motor image in the process of projecting the light source to the motor to be detected according to the adjusted shutter exposure time;

performing target detection on the new motor image, and determining a new moving distance of a preset mark in the motor image;

if the new moving distance is smaller than or equal to the preset distance threshold value, determining a preset rotating speed as the rotating speed of the motor to be detected;

and if the new moving distance is larger than the preset distance threshold, determining the rotating speed of the motor to be detected based on the new moving distance and the adjusted pulse period.

7. The method for measuring the rotational speed of a motor according to any one of claims 1 to 6, wherein the controlling the strobe light source projects a light source to the motor to be measured according to a preset pulse period, and the method comprises, before the controlling the camera to collect an image of the motor during the projection of the light source to the motor to be measured:

acquiring shutter exposure time of a camera and strobe times of a strobe light source in the shutter exposure time;

and determining a preset pulse period of the stroboscopic light source according to the shutter exposure time and the stroboscopic frequency.

8. A motor speed measurement device, the device comprising:

the image acquisition module is used for controlling the stroboscopic light source to project a light source to the motor to be detected according to a preset pulse period and controlling the camera to acquire a motor image in the process of projecting the light source to the motor to be detected; the surface of the motor rotating shaft to be detected is provided with a preset mark;

the distance detection module is used for carrying out target detection on the motor image and determining the moving distance of a preset mark in the motor image;

and the rotating speed measuring module is used for determining the rotating speed of the motor to be measured based on the moving distance and the preset pulse period.

9. An electronic device comprising a memory and a processor; the memory stores an application program, and the processor is configured to execute the application program in the memory to perform the operations in the motor rotation speed measurement method according to any one of claims 1 to 7.

10. A storage medium storing a plurality of instructions adapted to be loaded by a processor to perform the steps of the motor speed measurement method of any one of claims 1 to 7.