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 rotation speed measuring method and device, electronic equipment and storage medium

Technical Field

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

Background

In the operation of the generator set, the rotation speed of a motor in the generator set needs to be detected, and the operation state of the generator set is determined.

The existing method for measuring the rotating speed of the generator set mainly comprises the steps of measuring the speed through a fluted disc, installing annular toothed equipment at the end part of a rotating shaft of the generator, installing a fluted disc speed measuring sensor and a corresponding rotating speed signal processor on a fixed part, generating pulse signals reflecting the rotating speed of the generator set through induction of a proximity type or photoelectric type sensor when the generator set rotates, processing the pulse signals through an upper computer, measuring the pulse width, and calculating and obtaining the rotating speed of the generator set.

However, due to machining accuracy limitations, the tooth-to-tooth distance (i.e., pitch) on the toothed disc cannot be exactly equal, while high sensitivity sensors calculate speed by scanning the tooth-to-tooth time. The rotating speed of the unit is unchanged, the calculated speed is changed due to the change of the tooth pitch, and an interference signal is generated, so that the accuracy of a measurement result is reduced.

Disclosure of Invention

The embodiment of the invention provides a motor rotating speed measuring method, a motor rotating speed measuring device, electronic equipment and a storage medium, so as to improve the accuracy of generator rotating speed measurement.

In one aspect, an embodiment of the present invention provides a method for measuring a rotational speed of a motor, including:

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.

In another aspect, an embodiment of the present invention provides a motor rotation speed measurement device, including:

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.

In another aspect, 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 configured to run the application program in the memory, so as to execute the operation in the motor rotation speed measurement method.

In another aspect, an embodiment of the present invention provides a storage medium storing a plurality of instructions adapted to be loaded by a processor to perform the steps in the above-mentioned motor rotation speed measurement method.

The embodiment of the invention provides a motor rotating speed measuring method, a device, electronic equipment and a storage medium, which relate to the technical field of generator on-line monitoring and are characterized in that a stroboscopic light source is controlled to project a light source to a motor to be measured 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 measured; the method comprises the steps that a preset mark is arranged on the surface of a motor rotating shaft to be detected, target detection is conducted on a motor image, the moving distance of the preset mark in the motor image is determined, and the rotating speed of the motor to be detected is determined 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.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a motor rotation speed measurement system according to an embodiment of the present invention;

fig. 2 is a schematic flow chart of a motor rotation speed measurement method according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of shutter exposure time and pulse period of a strobe light source for a camera according to an embodiment of the present invention;

fig. 4 is a flow chart of a method for detecting a moving distance of a preset mark according to an embodiment of the present invention;

fig. 5 is a flow chart of another method for measuring a rotational speed of a motor according to an embodiment of the present invention;

fig. 6 is a schematic structural diagram of a motor rotation speed measuring device according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments may be embodied in many 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 concept 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 give a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, devices, steps, etc. In other instances, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

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

The flow diagrams depicted in the figures are exemplary only, and do not necessarily include all of the elements and operations/steps, nor must they be performed in the order described. For example, some operations/steps may be decomposed, and some operations/steps may be combined or partially combined, so that the order of actual execution may be changed according to actual situations.

It should be noted that: references herein to "a plurality" means two or more. "and/or" describes an association relationship of an association object, meaning that there may be three relationships, e.g., a and/or B may represent: a exists alone, A and B exist together, and B exists alone. The character "/" generally indicates that the context-dependent object is an "or" relationship.

As described in the background, the distance between teeth (i.e., pitch) on the toothed disc cannot be exactly equal due to the limitation of machining accuracy, whereas a high sensitivity sensor calculates the speed by scanning the time between teeth. The rotating speed of the machine set is unchanged, the calculated speed is changed due to the change of the tooth pitch, and an interference signal is generated, so that the measuring result of the fluted disc-based speed measuring method is reduced; the fluted disc speed measuring sensor has a sensing threshold, and the generator is possibly exactly at the sensing threshold of the sensor in a stop state, and the fluted disc is possibly sensed by the speed measuring sensor due to the vibration of the generator set and the factory building, so that false alarm is caused, and the accuracy of the rotating speed measuring result is further reduced; the speed measuring method based on the fluted disc needs to add fluted disc equipment on the rotating part, so that the complexity of the system is increased, and meanwhile, certain safety risk is brought by adding the equipment on the rotating part; in addition, finally, because the temperature measurement range of the sensor is limited, the sensor installed on the fixed part is usually only 1-2mm away from the fluted disc, equipment damage caused by the collision and grinding of the dynamic and static parts easily occurs, equipment needs to be replaced, and hardware cost is increased. The conventional fluted disc-based speed measuring method has the problems of inaccurate measuring results, complex measurement, high hardware cost and potential safety hazard.

Based on the above, in order to improve the accuracy of the rotating speed measurement result of the generator, reduce the cost of measurement hardware and provide a rotating speed measurement method with convenient measurement and high safety, the embodiment of the invention provides a motor rotating speed measurement method, a device, electronic equipment and a storage medium, wherein a stroboscopic light source is controlled by a pulse signal to strobe, an imaging picture acquired by a camera in the stroboscopic process is analyzed, the pixel movement range of a preset mark in the analysis picture and a preset pulse period are utilized to realize the measurement of the rotating speed of the generator, and the problem of inaccurate rotating speed measurement caused by inconsistent tooth pitch of a fluted disc is avoided; and the structural part is not required to be added on the rotating part of the generator, the complexity of the system is reduced, the safety risk brought by adding the structural part on the rotating part is eliminated, in addition, the camera and the rotating shaft can keep a larger distance, and the risk of collision and grinding of the dynamic and static parts in the measuring method is eliminated.

In order to facilitate understanding of the technical scheme provided by the embodiment of the invention, the motor rotation speed measuring method, the device, the electronic equipment and the storage medium provided by the embodiment of the invention are introduced below in combination with specific application scenes.

As shown in fig. 1, fig. 1 is a schematic structural diagram of a motor rotation speed measurement system according to an embodiment of the present invention, where the motor rotation speed measurement system includes a motor to be measured, a camera, an upper computer, a pulse generator, and a dispersion light source. Wherein the camera may be an area camera, such as an industrial camera.

The upper computer is respectively connected with the camera and the pulse generator and is used for sending an instruction to the camera so that the camera can acquire motor images of the motor to be detected, sending the instruction to the pulse generator, controlling the pulse generator to send pulses to the stroboscopic light source, controlling the stroboscopic light source to project the light source to the motor to be detected according to a preset pulse period, receiving the motor images acquired by the camera, detecting targets of the motor images, determining the moving distance of preset marks in the motor images, and determining the rotating speed of the motor to be detected based on the moving distance and the preset pulse period.

In some embodiments, the surface of the rotating shaft of the motor to be tested is provided with a preset mark, as shown in fig. 1, and the surface of the rotating shaft of the motor to be tested is provided with oblique stripes. It should be noted that the preset marks shown in fig. 1 are only exemplary, and not limiting to the embodiment of the present invention, the preset marks may also be in the shapes of vertical stripes, circles, triangles, and the like.

Alternatively, the preset mark can be set on the surface of the rotating shaft of the motor to be tested in various modes such as spraying, printing, pasting and the like.

It can be understood that the pulse generator sends a pulse signal to the strobe light source based on a preset pulse period, the strobe light source projects the light source to the motor to be tested according to the pulse signal, because the strobe light source is an intermittent projection light source to the motor to be tested, no light source exists in the environment where the motor to be tested is located in the time period when the strobe light source does not project the light source to the motor to be tested, the camera cannot capture the preset mark on the surface of the rotating shaft, and when the strobe light source projects the light source to the motor to be tested, the camera captures the preset mark on the surface of the rotating shaft, in this way, the rotating shaft moves to cause the rotation of the preset mark on the surface of the rotating shaft according to the pulse signal in the process of projecting the light source to the motor to be tested through the strobe light source, and because the camera has shutter exposure time, when the strobe light source is projected to the motor to be tested in the preset pulse period, the camera captures the moving distance of the preset mark on the surface of the rotating shaft in the preset pulse period, and then the rotating speed of the motor to be tested can be obtained based on the moving distance of the preset mark on the surface of the rotating shaft in the preset pulse period. For example, when the strobe light source projects the light source to the motor to be measured twice in a preset pulse period, because there is a time difference between the projection time of the two light sources, the rotation of the preset mark on the surface of the rotating shaft is caused by the rotation of the rotating shaft in the time difference, so that in the motor image captured by the camera, two preset marks exist, and the moving distance of the preset mark in the motor image can be determined by calculating the distance between the two preset marks, so that the rotating speed of the motor to be measured is determined.

In some embodiments, as shown in fig. 1, the upper computer includes a database, a rotating shaft rotating speed calculating unit, a camera and a light source control unit, where the rotating shaft rotating speed calculating unit is connected with the data, the rotating shaft rotating speed calculating unit is used to receive a motor image collected by the camera, perform target detection on the motor image, determine a moving distance of a preset mark in the motor image, determine a rotating speed of a motor to be tested based on the moving distance and a preset pulse period, and write the rotating speed of the motor to be tested into the database; the camera and light source control unit is used for sending control instructions to the area array camera and sending control instructions to the pulse generator.

According to the motor rotating speed measuring system provided by the embodiment of 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 rotating speed of the generator is measured 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; and the structural part is not required to be added on the rotating part of the generator, the complexity of the system is reduced, the safety risk brought by adding the structural part on the rotating part is eliminated, in addition, the camera and the rotating shaft can keep a larger distance, and the risk of collision and grinding of the dynamic and static parts in the measuring method is eliminated.

Based on the motor rotation speed measurement system shown in fig. 1, an embodiment of the present invention provides a motor rotation speed measurement method, as shown in fig. 2, fig. 2 is a flow chart of the motor rotation speed measurement method provided in the embodiment of the present invention, and the motor rotation speed measurement method shown in fig. 1 may be applied to an upper computer in the motor rotation speed measurement system shown in fig. 1, and may also be applied to a computer device having a data processing capability, such as an industrial computer, a server, etc., where the embodiment of the present invention is not limited in detail. Specifically, the motor rotation speed measurement method includes at least steps 210 to 230, and is described in detail as follows:

step 210, controlling the stroboscopic light source to project the light source to the motor to be tested according to a preset pulse period, and controlling the camera to acquire the motor image in the process of projecting the light source to the motor to be tested.

Wherein, the surface of waiting to detect motor shaft is provided with the mark of predetermineeing.

In some embodiments, the preset pulse period may be preset by a worker.

In some embodiments, the camera has a shutter exposure time, so that in order to ensure that the camera can capture the position information of the preset marks set on the surface of the rotating shaft of the motor to be tested at different times within the shutter exposure time, it is required to ensure that the strobe light source can project the light source to the motor to be tested at least twice within the shutter exposure time, based on which the preset pulse period can be determined according to the shutter exposure time of the camera.

Optionally, a shooting instruction is sent to the camera, a 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, the pulse signal is sent to the stroboscopic light source, the stroboscopic light source triggers the on-off of the light source based on the pulse signal, the light source is projected to the motor to be detected, and the camera responds to the shooting instruction to acquire a motor image in the process of projecting the light source to the motor to be detected.

In some embodiments, in order to ensure that the collected motor images can record the position information of the preset marks at different times, the camera can be controlled to continuously shoot according to the preset frame rate and the shutter exposure time, and in the continuous shooting process of the camera, the strobe light source is controlled to project the light source to the motor to be detected according to the preset pulse period, so that at least one motor image recorded with the position information of the preset marks at different times exists in the multiple motor images collected by the camera.

Optionally, a shooting instruction may be sent to the camera at each preset time interval, a 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, the pulse signal is sent to the strobe light source, the strobe light source triggers the on-off of the light source based on the pulse signal, the light source is projected to the motor to be detected, the camera responds to the shooting instruction, the camera frame rate, the shutter exposure time and the shooting time of the camera are determined, and the camera continuously shoots within the shooting time according to the camera frame rate and the shutter exposure time, so that a plurality of motor images are obtained.

And 220, performing target detection on the motor image, and determining the moving distance of a preset mark in the motor image.

In some embodiments, the target detection may be performed on the motor image by using a preset detection model, so as to obtain a moving distance of a preset mark in the motor image. The detection model may be a detection model based on machine learning, such as a detection model based on dictionary learning, or may be 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 YOLO.

In some embodiments, target detection may be performed on the motor image, preset marks at different positions in the motor image are determined, and a movement distance of the preset marks in the motor image is obtained according to a pixel distance between the preset marks. The pixel distance may be a distance between preset marks in an image coordinate system where the motor image is located, or the pixel distance may be a number of pixels between preset marks in the motor image.

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

In some embodiments, target detection may be performed on the motor image, whether at least two preset marks exist in the motor image is determined, if at least two preset marks exist, an image area where each preset mark in the motor image is determined, and a movement distance of the preset mark in the motor image is obtained based on position information of the image area where each preset mark exists; if at least two preset marks are not present, discarding the motor image, and performing target detection on the next motor image or re-acquiring the motor image.

In some embodiments, the motor image and the pre-stored reference image may 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, an image area where the preset marks are located in the difference image is determined, and a moving distance of the preset marks in the motor image is obtained based on position information of the image area where each preset mark is located. The preset reference image may be an image in which a preset mark is not present.

Step 230, determining the rotation speed of the motor to be tested based on the moving distance and the preset pulse period.

In some embodiments, after determining the moving distance, the rotation speed of the motor to be measured may be obtained by moving the distance/a preset pulse period according to the moving distance and the preset pulse period.

In some embodiments, after determining the moving distance, the linear speed of the motor to be tested may be obtained by moving the distance and the preset pulse period, and the rotational speed of the motor to be tested may be obtained by 120×pi×radius of the rotating shaft and the linear speed according to the rotating shaft radius and the linear speed of the rotating shaft of the motor to be tested.

In some embodiments, after determining the moving distance, the linear speed of the motor to be detected may be obtained by moving the distance and the preset pulse period, and the rotational speed of the motor to be detected may be obtained based on a mapping relationship between the preset linear speed and the rotational speed of the motor to be detected. The preset mapping relation between the linear speed and the rotating speed of the motor to be detected is used for indicating the mapping relation between the linear speed and the corresponding rotating speed of the motor to be detected.

In some embodiments, if a plurality of motor images exist, an initial rotation speed corresponding to each motor image can be obtained according to a movement distance of a preset mark in each motor image, and average processing is performed on the initial rotation speeds corresponding to the motor images to obtain the rotation speed of the motor to be detected; if one motor image exists, determining the initial rotating speed corresponding to the motor image as the rotating speed of the motor to be detected.

In some embodiments, the steps 210 to 230 may be performed at intervals of a preset duration within a period of time to obtain a rotation speed sequence of the motor to be tested, detect a rotation state of the motor to be tested based on the rotation speed sequence of the motor to be tested, determine whether the rotation state of the motor to be tested is abnormal, and send warning information to prompt a worker to maintain the motor to be tested when the rotation state of the motor to be tested is abnormal. The rotation state comprises abnormal rotation and normal rotation.

The method includes the steps of determining that a motor to be tested rotates abnormally when rotational speeds continuously larger than a preset rotational speed threshold exist in a rotational speed sequence of the motor to be tested, and determining that the motor to be tested rotates normally when the rotational speeds in the rotational speed sequence of the motor to be tested are smaller than or equal to the preset rotational speed threshold.

According to the motor rotating speed measuring method provided by the embodiment of 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 rotating speed of the generator is measured 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; and the structural part is not required to be added on the rotating part of the generator, the complexity of the system is reduced, the safety risk brought by adding the structural part on the rotating part is eliminated, in addition, the camera and the rotating shaft can keep a larger distance, and the risk of collision and grinding of the dynamic and static parts in the measuring method is eliminated.

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

step a1, acquiring shutter exposure time of a camera and the frequency of strobing a strobing light source in the shutter exposure time.

Step a2, determining a preset pulse period of the stroboscopic light source according to the shutter exposure time and the stroboscopic frequency.

In some implementations, a shutter exposure time of a camera by a worker based on configuration page view input, and a number of strobes of a strobe light source may be obtained.

In some embodiments, the shutter exposure time of the camera and the number of strobes of the strobe light source sent by the background server may be obtained.

In some embodiments, the preset pulse period of the strobe light source may be obtained from the shutter exposure time/strobe number according to the shutter exposure time and strobe number.

For example, taking the strobe frequency of the strobe light source in the shutter exposure time as 2 as an example, as shown in fig. 3, fig. 3 is a schematic diagram of the shutter exposure time and the pulse period of the strobe light source of the camera provided in the embodiment of the present invention, two pulse signals are triggered in one shutter exposure time T, the period in the pulse between the pulse signals is t=t/2, each pulse lasts for a time T1, where K is the frame rate of the camera, and 1/K is the shooting frequency of the camera.

According to the embodiment of the invention, the preset pulse period of the stroboscopic light source is determined through the shutter exposure time and the stroboscopic frequency, so that the stroboscopic light source can project the stroboscopic frequency light source to the motor to be detected within the shutter exposure time.

Considering that the motor continues to rotate within the shutter exposure time, a plurality of preset marks may exist in the motor image acquired by the camera, and each preset mark has a different position in the motor image, and the moving distance of the preset mark may be obtained by detecting the distance between the outlines of the plurality of preset marks. Based on this, in some embodiments, edge detection may be performed on the motor image, a contour of each preset mark in the motor image is determined, and a moving distance of the preset mark in the motor image is determined based on a distance between the contours of each preset mark in the motor image.

Optionally, edge detection can be performed on the motor image through an edge detection operator, so that the outline of each preset mark in the motor image is determined. Among them, the edge detection operators include, but are not limited to, gradient operators, sobel (chinese: discrete differential operator), roberts (chinese: gradient computing method of diagonal bias difference), prewitt (edge detection operator of differential operator), canny (chinese: optimal stepped edge detection operator), and Laplacian (chinese: second order differential operator) edge recognition operator.

The distance between the outlines of each preset mark in the motor image can be the distance between the outer edges of the outlines of each preset mark in the motor image; or the distance between the inner edges of the outline of each preset mark in the motor image; it is also possible to be the distance between the center points of the contours of each preset mark in the motor image.

In some embodiments, the distance between the contours of each preset mark in the motor image may be determined as the moving distance of the preset mark in the motor image.

In some embodiments, the moving distance of the preset marks in the motor image may be obtained according to 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 mapping relation between the preset image distance and the actual distance is used for indicating the mapping relation between the image distance and the corresponding actual distance under the actual coordinate system. In some embodiments, the mapping relationship between the preset image distance and the actual distance may be a mapping function between the image distance and the actual distance, for example, a conversion function between an image coordinate system and a world coordinate system.

Alternatively, when two preset marks exist in the motor image, the moving distance of the preset marks in the motor image can be obtained according to the distance between the outlines of the preset marks.

Alternatively, when more than two preset marks exist in the motor image, the maximum distance in the distance between the outlines of each preset mark in the motor image can be determined as the target outline distance, and the moving distance of the preset mark in the motor image is obtained according to the target outline distance, for example, the target outline distance is determined as the moving distance of the preset mark in the motor image; for example, according to the target contour distance and the mapping relation between the preset image distance and the actual distance, the moving distance of the preset mark in the motor image is obtained.

In order to improve the accuracy of edge detection, and then improve the accuracy of the moving distance of the preset mark in the motor image, so as to ensure the reliability of the rotating speed measurement result, in some embodiments, the motor image can be preprocessed, and the edge detection is performed based on the preprocessed motor image, so that the accuracy of the edge detection is improved by improving the image quality of the motor image, and then the accuracy of the moving distance of the preset mark in the motor image is improved, so that the reliability of the rotating speed measurement result is ensured. Among them, preprocessing includes, but is not limited to, image sharpening, gray stretching, image noise reduction, image edge enhancement, etc.

Specifically, as shown in fig. 4, fig. 4 is a flow chart of a method for detecting a moving distance of a preset mark according to an embodiment of the present invention, where the method for detecting a moving distance of a preset mark includes steps 221 to 223:

step 221, preprocessing the motor image to obtain a preprocessed motor image.

Step 222, performing edge detection on the preprocessed motor image, and determining the outline of each preset mark in the preprocessed motor image.

Step 223, determining the pixel distance between the contours, and determining the moving distance of the preset mark in the preprocessed motor image based on the pixel distance between the contours.

In some embodiments, the image coordinates of the center point of each preset mark under the image coordinate system where the motor image is located may be determined according to the profile of each preset mark, and the pixel distance between the profiles may be obtained based on the distance between the image coordinates of the center point of each preset mark. For example, the euclidean distance or mahalanobis distance between the image coordinates of the center points of the contours of the respective preset marks may be determined as the pixel distance between the contours based on the image coordinates of the center points of the contours of the respective preset marks. The center point may be a geometric center point or a center of gravity point.

In some embodiments, the image coordinates of the edges of the contours of each preset mark under the image coordinate system where the motor image is located may be determined according to the contours of each preset mark, and the pixel distance between the contours of each preset mark is determined based on the image coordinates of the edges of the contours of each preset mark under the image coordinate system where the motor image is located. The edge may be an outer edge or an inner edge.

In some embodiments, the pixel distance between the contours of each preset mark may 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. The preset key point may be a center point of the contour, or may be a center point of an edge in the contour, or may be any point in the contour.

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

(1) And 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.

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

Optionally, the position information of the preset key points in each contour in the motor image may be compared to obtain the image length between the preset key points in each contour, and the number of pixels between the preset key points in each contour is obtained based on the image length between the preset key points in each contour and the resolution of the motor image.

Alternatively, 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 number of pixels between the preset key points in each contour.

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

In some embodiments, further after determining the pixel distance, in order to ensure accuracy of calculation of the movement distance, the actual physical size represented by each pixel in the motor image needs to be considered, so that the movement distance of the preset mark in the preprocessed motor image is determined, that is, the preset pixel precision of the camera and the pixel distance are required, and the movement distance of the preset mark in the preprocessed motor image is determined, where the preset pixel precision of the camera is used to represent the actual physical size represented by each pixel in the image captured by the camera. Specifically, the moving distance determining method based on the pixel distance includes:

(1) And obtaining the initial moving distance of the preset mark in the preprocessed motor image based on the pixel distance between the outlines and the preset pixel precision of the camera.

(2) And obtaining a correction coefficient between the pixel length and the actual distance according to the image height of the preset mark in the preprocessed motor image and the preset actual height of the preset mark.

(3) 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.

In some embodiments, the initial movement distance of the preset mark in the preprocessed motor image may be obtained according to the pixel distance between the contours and the preset pixel precision of the camera, and by the pixel distance.

In some embodiments, the physical distance between the contours may be obtained by presetting the pixel precision according to the pixel distance between the contours and the preset pixel precision of the camera, and the farthest distance in the physical distance between the contours is determined as the initial moving distance of the preset mark in the preprocessed motor image.

Wherein the correction coefficient is used for indicating a 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 may be used to obtain the correction coefficient through the image height/the preset actual height. The image height represents the height of a preset mark under an image coordinate system where the motor image is located.

In some embodiments, the moving distance of the preset mark in the preprocessed motor image may be obtained by using the correction coefficient.

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 measured may be determined according to the determination method of the rotation speed of the motor to be measured in step 230.

Considering that the low-speed motion of the motor shaft occurs due to the vibration of a factory building or the inertial motion after the motor is shut down, or when the motor runs at a low speed, the position change of the preset mark is difficult to capture in the shutter exposure time of the camera, or the position change of the preset mark is small, therefore, if the camera uses the same shutter exposure time for image acquisition, the problem of low accuracy of calculation of the moving distance may exist, and the accuracy of the rotating speed measurement result is reduced. Based on this, to ensure accuracy of the rotational speed measurement, in some embodiments, after the movement distance is obtained, the movement distance is compared with a preset distance threshold, and when the movement distance is less than or equal to the preset distance threshold, the shutter exposure time of the camera is adjusted, thereby ensuring that the position change of the preset mark can be captured within the shutter exposure time of the camera. Specifically, as shown in fig. 5, fig. 5 is a flow chart of another motor rotation speed measurement method according to an embodiment of the present invention, where the motor rotation speed measurement method at least includes steps 510 to 580:

Step 510, controlling the strobe light source to project the light source to the motor to be tested according to a preset pulse period, and controlling the camera to collect the motor image in the process of projecting the light source to the motor to be tested.

In some embodiments, referring to step 210 in the motor rotation speed measurement method provided in fig. 2, the strobe light source is controlled to project a light source to the motor to be measured according to a preset pulse period, and the camera is controlled to collect a motor image during the process of projecting the light source to the motor to be measured, which is not described in detail herein.

In some embodiments, a preset pulse period may be determined according to the method for determining a pulse period provided in steps a1 to a2, and referring to step 210 in the method for measuring motor rotation speed provided in fig. 2, the strobe light source is controlled to project a light source to a motor to be measured according to the preset pulse period, and the camera is controlled to collect a motor image in the process of projecting the light source to the motor to be measured.

And step 520, performing target detection on the motor image, and determining the moving distance of a preset mark in the motor image.

In some embodiments, the moving distance of the preset mark in the motor image may be determined by referring to the method for detecting the moving distance of the preset mark provided in fig. 4, which is not described herein.

And step 530, if the moving distance is greater than the preset distance threshold, determining the rotating speed of the motor to be tested based on the moving distance and the preset pulse period.

In some embodiments, the moving distance may be compared with a preset distance threshold, and if the moving distance is greater than the preset distance threshold, the rotation speed of the motor to be measured is determined according to step 230 in the motor rotation speed measurement method provided in fig. 2, which is not described in detail herein.

Step 540, if the moving distance is less than or equal to the preset distance threshold, adjusting the shutter exposure time of the camera and adjusting the pulse period.

In some embodiments, if the moving distance is less than or equal to the preset distance threshold, an adjustment coefficient is obtained, the shutter exposure time of the camera is adjusted based on the adjustment coefficient, and the adjusted pulse period is obtained by the adjusted shutter exposure time/the strobe number of the strobe light source based on the adjusted shutter exposure time and the strobe number of the strobe light source. Wherein the adjustment coefficient is an integer greater than 1.

Alternatively, the adjusted shutter exposure time may be obtained by adjusting the shutter exposure time of the camera by a factor.

Alternatively, the adjusted shutter exposure time may be obtained by adjusting the shutter exposure time of the camera by 2 (adjustment factor).

Optionally, the adjustment coefficients may be obtained from a preset adjustment coefficient sequence; optionally, an adjustment coefficient input by a worker can be obtained; alternatively, the number of adjustments of the shutter exposure time may be acquired, the number of adjustments may be determined as an adjustment coefficient, or 2 (the number of adjustments) may be determined as an adjustment coefficient.

Step 550, based on the adjusted pulse period, projecting a light source to the motor to be tested, controlling the camera to collect a new motor image in the process of projecting the light source to the motor to be tested according to the adjusted shutter exposure time.

In some embodiments, in step 210 of the motor rotation speed measurement method provided in fig. 2, a light source is projected to a motor to be measured based on the adjusted pulse period, and the camera is controlled to collect a new motor image in the process of projecting the light source to the motor to be measured according to the adjusted shutter exposure time, which is not described in detail herein.

Step 560, performing object detection on the new motor image, and determining a new moving distance of the preset mark in the motor image.

In some embodiments, the method for detecting the moving distance of the preset mark provided in fig. 4 may be referred to determine a new moving distance of the preset mark in the motor image, which is not described herein.

In step 570, if the new moving 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 moving distance is less than or equal to the preset distance threshold, repeating steps 540-560 to obtain a new moving distance, and if the new moving distance is less than or equal to the preset distance threshold, indicating that the rotating shaft of the motor to be tested has no rotating speed or is too low, determining the set rotating speed as the rotating speed of the motor to be tested. Wherein the preset rotational speed may be 0/s.

In some embodiments, if the new movement distance is less than or equal to the preset distance threshold, the shutter exposure time adjustment number is greater than the preset number threshold, and the set rotation speed is determined as the rotation speed of the motor to be measured; if the shutter exposure time adjustment times is less than or equal to the preset times threshold, repeating steps 540-560 to obtain a new movement distance.

In 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 measured is determined based on the new moving distance and the adjusted pulse period.

In some embodiments, if the new moving distance is greater than the preset distance threshold, the rotational speed of the motor to be measured is determined according to step 230 in the motor rotational speed measurement method provided in fig. 2, which is not described in detail herein.

According to the motor rotating speed measuring method provided by the embodiment of the invention, through increasing the detection of the moving distance, when the rotating speed is too low or no rotating speed, and the pixel precision is insufficient, the camera shutter exposure time is automatically controlled, and the effective moving distance is obtained through increasing the shutter exposure time, so that parameters of equipment such as a camera, a pulse generator and the like are matched with the current rotating speed of a motor to be measured, more accurate measurement is performed, and the problem of inaccurate rotating speed measuring results caused by the too low rotating speed or factory building vibration is avoided.

In order to better implement the motor rotation speed measuring method provided by the embodiment of the present invention, on the basis of the motor rotation speed measuring method, the embodiment of the present invention provides a motor rotation speed measuring device, as shown in fig. 6, fig. 6 is a schematic structural diagram of the motor rotation speed measuring device provided by the embodiment of the present invention, where the motor rotation speed measuring device includes:

the image acquisition module 601 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 602 is configured to perform target detection on the motor image, and determine a moving distance of a preset mark in the motor image;

the rotation speed measurement module 603 is configured to determine a rotation speed of the motor to be measured based on the moving distance and a preset pulse period.

In some implementations, the distance detection module 602 includes:

the image preprocessing unit is used for preprocessing the motor image to obtain a preprocessed motor image;

the edge detection unit is used for carrying out edge detection on the preprocessed motor image and determining the outline of each preset mark in the preprocessed motor image;

and the distance detection unit is used for determining the pixel distance between the outlines and determining the moving distance of the preset mark in the preprocessed motor image based on the pixel distance between the outlines.

In some embodiments, the distance detection unit is configured to:

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

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

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.

In some embodiments, the distance detection unit is configured to:

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;

the number of pixels between preset key points in each contour is determined as the pixel distance between each contour.

In some embodiments, the rotational speed measurement module 603 is configured to:

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

acquiring the radius of a rotating shaft of a 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.

In some embodiments, the motor speed measurement device further comprises:

a feedback adjustment module 604, configured to adjust the shutter exposure time of the camera and adjust the pulse period if the moving distance is less than or equal to the preset distance threshold;

the image acquisition module 601 is configured to project a light source to a motor to be tested based on the adjusted pulse period, control the camera to acquire a new motor image in the process of projecting the light source to the motor to be tested according to the adjusted shutter exposure time;

The distance detection module 602 is configured to perform target detection on a new motor image, and determine a new moving distance of a preset mark in the motor image;

the rotation speed measurement module 603 is configured to determine a preset rotation speed as a rotation speed of the motor to be measured if the new movement distance is less than or equal to a preset distance threshold; if the new moving distance is larger than the preset distance threshold, determining the rotating speed of the motor to be tested based on the new moving distance and the adjusted pulse period.

In some embodiments, the motor speed measurement device further comprises:

a control module 605 for acquiring a shutter exposure time of the camera and a strobe number of strobe light sources during 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.

According to the motor rotating speed measuring device provided by the embodiment of 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 rotating speed of the generator is measured 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; and the structural part is not required to be added on the rotating part of the generator, the complexity of the system is reduced, the safety risk brought by adding the structural part on the rotating part is eliminated, in addition, the camera and the rotating shaft can keep a larger distance, and the risk of collision and grinding of the dynamic and static parts in the measuring method is eliminated.

The embodiment of the invention also provides an electronic device, as shown in fig. 7, which shows a schematic structural diagram of the electronic device according to the embodiment of the invention, specifically:

the electronic device may include one or more processing cores 'processors 701, one or more computer-readable storage media's memory 702, power supply 703, and input unit 704, among other components. It will be appreciated by those skilled in the art that the electronic device structure shown in fig. 7 is not limiting of the electronic device and may include more or fewer components than shown, or may combine certain components, or a different arrangement of components. Wherein:

the processor 701 is a control center of the electronic device, connects various parts of the entire electronic device using various interfaces and lines, and performs various functions of the electronic device and processes data by running or executing software programs and/or modules stored in the memory 702, and calling data stored in the memory 702, thereby performing overall monitoring of the electronic device. Optionally, processor 701 may include one or more processing cores; preferably, the processor 701 may integrate an application processor and a modem processor, wherein the application processor primarily handles operating systems, user interfaces, applications, etc., and the modem processor primarily handles wireless communications. It will be appreciated that the modem processor described above may not be integrated into the processor 701.

The memory 702 may be used to store software programs and modules, and the processor 701 executes various functional applications and data processing by executing 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 (such as a sound playing function, an image playing function, etc.) required for at least one function, and the like; the storage data area may store data created according to the use of the electronic device, etc. In addition, the 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 access to the memory 702 by the processor 701.

The electronic device further comprises a power supply 703 for powering the various components, preferably the power supply 703 is logically connected to the processor 701 by a power management system, whereby the functions of managing charging, discharging, and power consumption are performed by the power management system. The power supply 703 may also include one or more of any component, such as a direct current or alternating current power supply, a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator, etc.

The electronic device may further comprise an input unit 704, which input unit 704 may be used for receiving input digital or character information and generating keyboard, mouse, joystick, optical or trackball signal inputs in connection with user settings and function control.

Although not shown, the electronic device may further include a display unit or the like, which is not described herein. In particular, in this embodiment, the processor 701 in the electronic device loads 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 executes the application programs stored in the memory 702, so as to implement various functions as follows:

the stroboscopic light source is controlled to project a light source to the motor to be tested according to a preset pulse period, and the camera is controlled 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 a preset pulse period.

Those of ordinary skill in the art will appreciate that all or a portion of the steps of the various methods of the above embodiments may be performed by instructions, or by instructions controlling associated hardware, which may be stored in a computer-readable storage medium and loaded and executed by a processor.

To this end, an embodiment of the present invention provides a storage medium having stored therein a plurality of instructions that can be loaded by a processor to perform the steps of any one of the motor rotation speed measurement methods provided by the embodiment of the present invention. For example, the instructions may perform the steps of:

the stroboscopic light source is controlled to project a light source to the motor to be tested according to a preset pulse period, and the camera is controlled 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 a preset pulse period.

The specific implementation of each operation above may be referred to the previous embodiments, and will not be described herein.

Wherein the storage medium may include: read Only Memory (ROM), random access Memory (RAM, random Access Memory), magnetic or optical disk, and the like.

The steps in any motor rotation speed measuring method provided by the embodiment of the present invention can be executed due to the instructions stored in the storage medium, so that the beneficial effects of any motor rotation speed measuring method provided by the embodiment of the present invention can be achieved, and detailed descriptions of the foregoing embodiments are omitted.

The foregoing describes in detail a motor rotation speed measuring method, apparatus, electronic device and storage medium provided by the embodiments of the present invention, and specific examples are applied to illustrate the principles and embodiments of the present invention, where the foregoing examples are only used to help understand the method and core idea of the present invention; meanwhile, as those skilled in the art will have variations in the specific embodiments and application scope in light of the ideas of the present invention, the present description should not be construed as limiting the present 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.