CN113409274A

CN113409274A - Magnetic bearing rotor position detection method, device, medium, controller and system

Info

Publication number: CN113409274A
Application number: CN202110688333.8A
Authority: CN
Inventors: 赵聪; 霍玥潼; 李雪
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2021-06-21
Filing date: 2021-06-21
Publication date: 2021-09-17

Abstract

The invention provides a magnetic suspension bearing rotor position detection method, a magnetic suspension bearing rotor position detection device, a storage medium, a controller and a magnetic suspension bearing system, wherein a micro camera device is arranged in the magnetic suspension bearing system, and the method comprises the following steps: acquiring an image of a rotor of the magnetic suspension bearing through the miniature camera device to obtain a rotor image of a target area; and comparing the acquired rotor image of the target area with the standard rotor suspension position image of the target area to determine the position information of the rotor. The scheme provided by the invention can reduce the structural complexity of the magnetic suspension bearing and can realize accurate measurement on the position of the rotor.

Description

Magnetic bearing rotor position detection method, device, medium, controller and system

Technical Field

The invention relates to the field of control, in particular to a magnetic bearing rotor position detection method, a magnetic bearing rotor position detection device, a magnetic bearing rotor position detection medium, a magnetic bearing rotor position detection controller and a magnetic bearing rotor position detection system.

Background

The magnetic bearing system works by obtaining the displacement of the offset reference point of the rotor, converting the displacement into a digital signal and transmitting the digital signal to a microprocessor serving as a controller, comparing the digital signal with a reference signal by the controller to react, transmitting the corrected signal to a power amplifier, and adjusting the control current of an electromagnet by the power amplifier to change the electromagnetic force generated by the electromagnet, so that the rotor returns to a standard balance state.

The displacement sensor is a commonly used measuring component in a magnetic bearing system, generally 2 sensor probes need to be placed axially, 8 sensor probes need to be placed radially, and the displacement sensor is complex in structure and is easily influenced by materials, environment temperature and the like; the sensorless measurement method determines the position of a rotor by detecting back electromotive force and current of fundamental waves, but when the magnetic bearing rotor is in a static state, the fundamental wave measurement method cannot be realized, so that the method cannot completely meet the control requirement of the magnetic bearing; the displacement can also be determined by using the nonlinear relation between the mutual inductance between the magnetic suspension winding and the switching torque winding and the radial displacement of the rotor, but the measurement precision is poor, manual intervention judgment is needed, and the axial displacement and the like cannot be measured simultaneously.

Disclosure of Invention

The present invention is directed to overcome the above-mentioned drawbacks of the related art, and provides a method and an apparatus for detecting a position of a magnetic bearing rotor, a storage medium, a controller, and a magnetic bearing system, so as to solve the problem of measuring a displacement of a magnetic bearing rotor in the related art.

The invention provides a magnetic suspension bearing rotor position detection method, wherein a miniature camera device is arranged in a magnetic suspension bearing system, and the method comprises the following steps: acquiring an image of a rotor of the magnetic suspension bearing through the miniature camera device to obtain a rotor image of a target area; and comparing the acquired rotor image of the target area with the standard rotor suspension position image of the target area to determine the position information of the rotor.

Optionally, comparing the acquired rotor image of the target area with the standard rotor levitation position image of the target area to determine the position information of the rotor, including: identifying image pixel points in the rotor image of the target area, and carrying out numerical conversion on the image pixel points; comparing the rotor image of the target area obtained after conversion with the rotor standard suspension position image to obtain a difference parameter image; and determining the position information of the rotor according to the difference parameter image obtained by comparison.

Optionally, comparing the converted rotor image with the standard rotor levitation position image to obtain a difference parameter image, including: carrying out AND operation on the converted rotor image and the numerical value of the corresponding position in the rotor standard suspension position image of the target area to obtain a difference pixel point, thereby obtaining a difference parameter image; and/or determining the position information of the rotor according to the difference parameter image obtained by comparison, wherein the position information comprises the following steps: measuring the difference parameter image to obtain the position information of the rotor; and/or determining the position information of the rotor by a coordinate method based on the difference parameter image.

Optionally, the measuring the difference parameter image to obtain the position information of the rotor, where the position information includes at least one of a rotor displacement amount, a rotor bending amount, and a rotor elongation amount, includes: measuring the maximum offset of the rotor in the x-axis direction and the y-axis direction on the difference parameter image through the ten-thousandth meter probe so as to calculate the rotor displacement according to the maximum offset of the rotor in the x-axis direction and the y-axis direction; and/or measuring the maximum displacement of the rotor bending on the difference parameter image through the ten-thousandth meter probe to serve as the rotor bending amount; and/or, measuring the rectangular width of the lateral sides at the two ends of the rotor and the lateral sides at the two ends of the standard suspension position of the rotor on the difference parameter image through the universal meter probe so as to serve as the extension amount of the rotor.

Optionally, determining the position information of the rotor by a coordinate method based on the difference parameter image includes: based on the difference parameter image, carrying out pixel point positioning by a coordinate method to obtain a difference pixel point coordinate in the difference parameter image; and determining the position information of the rotor according to the obtained difference pixel point coordinates in the difference parameter image.

Optionally, the position information includes at least one of a rotor displacement amount, a rotor bending amount and a rotor elongation amount; determining the position information of the rotor according to the obtained difference pixel point coordinates in the difference parameter image, wherein the determining comprises the following steps: determining the maximum offset of the rotor in the x-axis direction and the y-axis direction according to the obtained difference pixel point coordinates in the difference parameter image, and calculating the rotor displacement according to the maximum offset of the rotor in the x-axis direction and the y-axis direction; and/or determining the maximum displacement of the rotor which is bent according to the obtained difference pixel point coordinates in the difference parameter image to be used as the bending amount of the rotor; and/or according to the obtained difference pixel point coordinates in the difference parameter image, the rectangular widths of the lateral sides at the two ends of the rotor and the lateral sides at the two ends of the standard suspension position of the rotor are used as the rotor elongation.

Optionally, acquiring a rotor image of the target area through two micro cameras, wherein on a cross section of the rotor in the radial direction, straight lines passing through centers of the two micro cameras in the radial direction and edges of the rotor respectively form two intersection points, and rotor tangent lines passing through the two intersection points are mutually perpendicular; carrying out pixel point positioning by a coordinate method to obtain the coordinate of the difference pixel point in the difference parameter image, wherein the method comprises the following steps: taking the intersection point of the straight line passing through the centers of the two miniature camera devices in the radial direction of the rotor and the edge of the rotor as a tangent point to make a tangent line of the rotor, taking the intersection point of the two tangent lines as a coordinate origin, and taking the two tangent lines as an x axis and a y axis respectively to establish a coordinate system; and determining the coordinates of the difference pixel points by a three-point cooperation coordinate method based on the coordinate origin and the coordinates of the two miniature camera devices.

In another aspect, the present invention provides a magnetic suspension bearing rotor position detecting apparatus, in which a miniature camera device is disposed, the apparatus including: the acquisition unit is used for acquiring an image of the rotor of the magnetic suspension bearing through the miniature camera device to obtain a rotor image of a target area; and the determining unit is used for comparing the rotor image of the target area acquired by the acquiring unit with the standard rotor suspension position image of the target area so as to determine the position information of the rotor.

Optionally, the determining unit includes: the identification subunit is used for identifying image pixel points in the rotor image of the target area and carrying out numerical conversion on the image pixel points; the comparison subunit is used for comparing the rotor image of the target area obtained after conversion with the standard rotor suspension position image to obtain a difference parameter image; and the determining subunit is used for determining the position information of the rotor according to the difference parameter image obtained by comparison.

Optionally, the comparing and comparing subunit compares the converted rotor image with the standard rotor levitation position image to obtain a difference parameter image, and includes: carrying out AND operation on the converted rotor image and the numerical value of the corresponding position in the rotor standard suspension position image of the target area to obtain a difference pixel point, thereby obtaining a difference parameter image; and/or the determining subunit determines the position information of the rotor according to the difference parameter image obtained by comparison, including: measuring the difference parameter image to obtain the position information of the rotor; and/or determining the position information of the rotor by a coordinate method based on the difference parameter image.

Optionally, the position information includes at least one of a rotor displacement amount, a rotor bending amount and a rotor elongation amount, and the determining subunit measures the difference parameter image to obtain the position information of the rotor, including: measuring the maximum offset of the rotor in the x-axis direction and the y-axis direction on the difference parameter image through the ten-thousandth meter probe so as to calculate the rotor displacement according to the maximum offset of the rotor in the x-axis direction and the y-axis direction; and/or measuring the maximum displacement of the rotor bending on the difference parameter image through the ten-thousandth meter probe to serve as the rotor bending amount; and/or, measuring the rectangular width of the lateral sides at the two ends of the rotor and the lateral sides at the two ends of the standard suspension position of the rotor on the difference parameter image through the universal meter probe so as to serve as the extension amount of the rotor.

Optionally, the determining the sub-unit, which determines the position information of the rotor by a coordinate method based on the difference parameter image, includes: based on the difference parameter image, carrying out pixel point positioning by a coordinate method to obtain a difference pixel point coordinate in the difference parameter image; and determining the position information of the rotor according to the obtained difference pixel point coordinates in the difference parameter image.

Optionally, the position information includes at least one of a rotor displacement amount, a rotor bending amount and a rotor elongation amount; the determining subunit determines, according to the obtained difference pixel point coordinates in the difference parameter image, the position information of the rotor, including: determining the maximum offset of the rotor in the x-axis direction and the y-axis direction according to the obtained difference pixel point coordinates in the difference parameter image, and calculating the rotor displacement according to the maximum offset of the rotor in the x-axis direction and the y-axis direction; and/or determining the maximum displacement of the rotor which is bent according to the obtained difference pixel point coordinates in the difference parameter image to be used as the bending amount of the rotor; and/or according to the obtained difference pixel point coordinates in the difference parameter image, the rectangular widths of the lateral sides at the two ends of the rotor and the lateral sides at the two ends of the standard suspension position of the rotor are used as the rotor elongation.

Optionally, acquiring a rotor image of the target area through two micro cameras, wherein on a cross section of the rotor in the radial direction, straight lines passing through centers of the two micro cameras in the radial direction and edges of the rotor respectively form two intersection points, and rotor tangent lines passing through the two intersection points are mutually perpendicular; the determining subunit performs pixel location by a coordinate method to obtain a difference pixel coordinate in the difference parameter image, including: taking the intersection point of the straight line passing through the centers of the two miniature camera devices in the radial direction of the rotor and the edge of the rotor as a tangent point to make a tangent line of the rotor, taking the intersection point of the two tangent lines as a coordinate origin, and taking the two tangent lines as an x axis and a y axis respectively to establish a coordinate system; and determining the coordinates of the difference pixel points by a three-point cooperation coordinate method based on the coordinate origin and the coordinates of the two miniature camera devices.

A further aspect of the invention provides a storage medium having stored thereon a computer program which, when executed by a processor, carries out the steps of any of the methods described above.

In a further aspect, the present invention provides a magnetic bearing controller comprising a processor, a memory and a computer program stored on the memory and executable on the processor, wherein the processor executes the program to implement the steps of any of the methods described above.

The invention further provides a magnetic suspension bearing controller, which comprises the magnetic suspension bearing rotor position detection device.

In another aspect, the invention provides a magnetic suspension bearing system, which includes the magnetic suspension bearing controller.

According to the technical scheme of the invention, the rotor of the magnetic suspension bearing is subjected to image acquisition through the miniature camera device to obtain the rotor image of a target area, so that the acquired rotor image of the target area is compared with the standard suspension position image of the rotor of the target area to determine the position information of the rotor. The non-contact measurement method capable of replacing the displacement sensor obtains a rotor image through a plurality of miniature cameras, carries out digital processing, compares the rotor image with a standard value and further accurately determines whether the rotor is bent or displaced in the axial direction and the radial direction and the size of the position change quantity of the rotor; the method for determining the pixel points by using the universal meter to replace the coordinates improves the measurement precision of the related technology.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic method diagram of one embodiment of a magnetic bearing rotor position detection method provided by the present invention;

FIG. 2 shows a control schematic diagram of a magnetic bearing rotor with a single degree of freedom according to an embodiment of the invention;

FIG. 3 shows a magnetic bearing rotor system configuration;

FIG. 4 is a schematic flowchart of an embodiment of the step of comparing the acquired rotor image of the target area with the standard rotor levitation position image of the target area to determine the position information of the rotor;

FIG. 5 is a schematic diagram illustrating the principle of pixel point conversion of an image;

FIG. 6 is an image of a rotor being displaced;

FIG. 7 is a schematic view of the rotor as it bends;

FIG. 8 is an image of the rotor as it bends;

FIG. 9 is an image of the rotor actually obtained by the micro-camera with elongation;

FIG. 10 is a flowchart illustrating one embodiment of the step of determining position information of the rotor by a co-ordinate method based on the difference parameter image;

FIG. 11 is a simplified schematic diagram of three-point coordinated coordinate positioning of pixel points;

FIG. 12 is a schematic method diagram of one embodiment of a magnetic bearing rotor position detection method provided by the present invention;

FIG. 13 is a schematic method diagram of another embodiment of a magnetic bearing rotor position detection method provided by the present invention;

FIG. 14 is a block diagram of an embodiment of a magnetic bearing rotor position detection apparatus provided by the present invention;

FIG. 15 is a block diagram illustrating a particular implementation of a determination unit;

fig. 16 is a schematic diagram of the front micro-camera a and the upper micro-camera E in relation to the rotor position according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The magnetic suspension bearing system needs to obtain the offset displacement of the rotor, and the rotor is adjusted and controlled to be kept in a standard suspension working state. The displacement sensor is a commonly used measuring component in a magnetic bearing system, but the displacement sensor has a complex structure and is easily influenced by materials, environmental temperature and the like; by using a sensorless measurement method, when the magnetic bearing rotor is in a static state, the measurement of fundamental waves cannot be realized; the non-linear relation between the mutual inductance between the magnetic suspension winding and the switch torque winding and the radial displacement of the rotor is used for measurement, the measurement precision is poor, manual intervention judgment is needed, and the axial displacement cannot be measured simultaneously.

The invention provides a magnetic suspension bearing rotor position detection method and device. And the position of the magnetic suspension bearing rotor is judged based on image recognition, and the magnetic suspension bearing rotor can be judged instead of a displacement sensor.

According to the method and the device for detecting the position of the magnetic bearing rotor, the rotor image is acquired through the miniature camera device, so that the position of the magnetic bearing rotor is measured according to the image. A miniature camera, for example a miniature camera, is arranged in the magnetic bearing system. Rotor image acquisition is carried out through a miniature camera device, and measurement of the position of the rotor is achieved. The number of the micro camera devices is more than two.

Fig. 2 shows a control schematic diagram of a magnetic bearing rotor with a single degree of freedom according to an embodiment of the invention. Referring to fig. 2, after the rotor position information is acquired by the micro camera, the rotor position information is compared with a standard position reference circuit by a feedback circuit. If there is deviation signal e (the rotor has position deviation, bending, etc.), the controller generates voltage control signal according to the deviation signal, and obtains current signal through the power amplifier (shown as "power amplifier") to act on the electromagnet, so as to generate electromagnetic force to make the rotor return to the balance position.

In some embodiments, whether the rotor is bent or not and the degree of bending are detected by two micro-cameras disposed at lateral positions of the rotor: one micro camera device is arranged above the rotor side, the other micro camera device is arranged below the rotor side, the upper side and the side are relative, and when a certain direction is determined to be the upper side, the direction opposite to the upper side is the lower side; preferably, whether the rotor is bent or not and the degree of the bending are detected by a micro-camera device disposed at a lateral center position of the rotor. For example, a front micro camera B and a front micro camera C shown in fig. 3. Wherein, preceding miniature camera head B sets up in rotor side top, and preceding miniature camera head C sets up in rotor side below.

In some embodiments, the offset of the rotor is detected by two micro cameras disposed at different positions at the same end of the rotor, one micro camera being disposed directly above one end of the rotor, the other micro camera being disposed directly lateral to the same end, the upper side being relative to the lateral side, and when a certain direction is determined to be the upper side, the direction perpendicular to the upper side is the lateral side, and the direction perpendicular to the rotor (axial direction) and passing through the center line of the rotor. For example, the upper micro camera E and the front micro camera a shown in fig. 3, or the upper micro camera F and the front micro camera D. Wherein, go up miniature camera E and be located rotor one end directly over, preceding miniature camera A is located the positive side of rotor one end, the rotor is when normal suspended state, miniature camera E should not be all same shaft section rotor with A shooting within range, or go up miniature camera F and be located the rotor other end directly over, preceding miniature camera D is located the positive side of the rotor other end, the rotor is when normal suspended state, should not be all same shaft section rotor with D shooting within range. The positions of the micro camera A and the micro camera E are the same as the positions of the micro camera D and the micro camera F, the micro camera A and the micro camera D are located on the same side of the rotor, and the micro camera E and the micro camera F are located on the same side of the rotor.

In some embodiments, the amount of elongation of the rotor is detected by two micro cameras disposed at both ends of the rotor, for example, a front micro camera a and a front micro camera D shown in fig. 3.

Fig. 1 is a schematic method diagram of an embodiment of a magnetic bearing rotor position detection method provided by the invention. As shown in fig. 1, according to an embodiment of the present invention, the magnetic bearing rotor position detection method at least includes step S110 and step S120.

And step S110, acquiring an image of the rotor of the magnetic suspension bearing through the miniature camera device to obtain a rotor image of a target area.

Taking the single degree of freedom of the magnetic bearing rotor as an example, as shown in fig. 2, the position is measured in a non-contact manner by a micro camera. When the image of one pixel point or one line is obtained, due to system interference and the metal material of the rotor, if external light enters in the high-speed rotation, the problem of strong light reflection in a small range and the like is possibly caused, and the quality of the identified pixel point value is changed (the original 0 is identified as 1, and the original 1 is identified as 0). Therefore, the present invention obtains a rectangular image of a target area with a preset size (the preset size is, for example, a pixel size, and it needs to be considered that complete information can be obtained without distortion, for example, a rectangular image with 150 × 150 pixels is obtained).

Step S120, comparing the acquired rotor image of the target area with the standard rotor suspension position image of the target area to determine the position information of the rotor.

Fig. 4 is a schematic flowchart of a specific embodiment of the step of comparing the acquired rotor image of the target area with the standard rotor levitation position image of the target area to determine the position information of the rotor. As shown in fig. 4, step S120 includes step S121, step S122, and step S123.

And step S121, identifying image pixel points in the rotor image of the target area, and performing numerical conversion on the image pixel points.

Specifically, the positions where image pixels are acquired are identified as 1, and the positions where image pixels are not acquired are identified as 0. The pixel value of each pixel point is between 0 and 255, wherein 0 is pure black, 255 is pure white, and the image is changed into a digital matrix during storage, namely the image is stored through the pixel points. The invention simplifies the process, and records the position of the acquired image pixel as 1 and the position of the pixel which is not acquired as 0. For example, the acquired rotor image of the target region is subjected to a numerical value conversion process by the DSP, and the positions where the image pixel points are acquired are identified as a numerical value 1, and the positions where the image pixel points are not acquired are identified as a numerical value 0, which can refer to the schematic diagram of the principle of image pixel point conversion shown in fig. 5.

And S122, comparing the rotor image of the target area obtained after conversion with the standard rotor suspension position image to obtain a difference parameter image.

Specifically, the numerical values of the corresponding positions in the converted rotor image and the rotor standard levitation position image of the target area are subjected to AND operation to obtain difference pixel points, so that a difference parameter image is obtained. The standard rotor levitation position image of the target region may be preset, for example, the standard rotor levitation position image of the target region is set as the standard rotor levitation position image of the target region, where the size of the standard rotor levitation position image of the target region is the same as the preset size, for example, a rectangular image with 150 × 150 pixels.

For example, in an area with 150 × 150 pixels, the converted rotor image is compared with the rotor standard levitation position image in the order from left to right and from top to bottom, and the values of the two corresponding positions are summed to determine the difference pixel points, thereby obtaining the difference parameter image.

And S123, determining the position information of the rotor according to the difference parameter image obtained by comparison.

In one embodiment, the difference parameter image is measured to obtain position information of the rotor. More specifically, the difference parameter image is measured by a ten-thousandth chart to obtain the position information of the rotor. For example, a digital display ten-thousandth meter D62S can be selected, the parameters of which are shown in Table 1, the precision of the digital display ten-thousandth meter reaches 0.1um, the suspension error precision condition of the magnetic suspension bearing is met, and the calibration micro-measurement of horizontal and vertical displacement of a difference parameter image can be directly carried out, so that the position information is obtained.

D62S digital display ten-thousandth meter

TABLE 1

Optionally, the position information includes at least one of a rotor displacement amount, a rotor bending amount, and a rotor elongation amount. The target areas corresponding to different position information are different. For example, for the rotor displacement, the target region may be set as the two end regions of the rotor, i.e., the region image of any one of the two ends of the rotor may be acquired; for the amount of rotor bending, the target region may be set to a middle region of the rotor side, preferably a region axially midway of the rotor side. For the rotor elongation, the target area can be set as the two end areas of the rotor, i.e. images of the two end areas of the rotor can be acquired.

The following respectively describes specific ways of measuring the difference parameter image by a ten-thousandth chart to obtain the rotor displacement, the rotor bending and the rotor elongation:

(1) rotor displacement amount:

and measuring the maximum offset of the rotor in the x-axis direction and the y-axis direction on the difference parameter image through the ten-thousandth chart probe so as to calculate the rotor displacement according to the maximum offset of the rotor in the x-axis direction and the y-axis direction. An image of the rotor position shift is shown with reference to fig. 6. For example, a difference parameter image of the rotor position deviation and the rotor standard suspension position in the actual magnetic bearing system operation is obtained, and the rotor displacement can be obtained by determining the maximum deviation of the rotor in the x direction and the y direction and calculating according to the pythagorean theorem. The maximum offset of the x axis and the y axis of the rotor can be determined by directly measuring by using a universal meter probe, for example, the length of the side of a shadow region can be determined by placing the universal meter probe on the edge of a difference parameter image.

(2) Rotor bending amount:

and measuring the maximum displacement of the rotor bending on the difference parameter image through the ten-thousandth meter probe to serve as the rotor bending amount. The principle of the rotor when bending occurs can be seen with reference to fig. 7. And determining the maximum displacement in the difference parameter image of the rotor bending and the standard suspension position of the rotor in the actual magnetic bearing system operation, namely the rotor bending quantity delta x. The image of the rotor bending actually obtained by the micro-camera device is shown in fig. 8, and the maximum displacement in the difference parameter image of the rotor bending and the standard suspension position of the rotor during the actual magnetic bearing system operation is Δ x.

(3) Rotor elongation:

and measuring the rectangular widths of the two ends of the rotor and the two ends of the standard suspension position of the rotor on the difference parameter image through the ten-thousandth meter probe to serve as the extension amount of the rotor. The rotor elongation image actually acquired by the micro-camera is shown in fig. 9, and the rectangular width in the difference parameter image between the two end sides of the rotor and the two end sides of the standard suspension position of the rotor during the actual operation of the magnetic bearing system is determined, namely the rotor elongation. And obtaining a difference image according to the image after the rotor is stretched and the rotor standard position image, wherein when the rotor is stretched only (namely the situation shown in FIG. 9), the obtained difference image is a rectangular area, and the rotor stretching amount can be obtained by obtaining the rectangular width.

In another embodiment, the position information of the rotor is determined by a coordinate method based on the difference parameter image. Fig. 10 is a flowchart illustrating a step of determining position information of the rotor by a coordinate method based on the difference parameter image according to an embodiment of the present invention.

As shown in fig. 10, step S123 includes step S1231 and step S1232.

And S1231, based on the difference parameter image, carrying out pixel point positioning through a coordinate method to obtain the coordinates of the difference pixel points in the difference parameter image.

In some embodiments, two miniature cameras are used for acquiring a rotor image of the target area, on a cross section of the rotor in the radial direction, two intersection points are respectively formed by straight lines in the radial direction respectively passing through the centers of the two miniature cameras and the edge of the rotor, and rotor tangent lines passing through the two intersection points are mutually perpendicular; that is, rotor tangents are perpendicular to each other with an intersection point of a straight line passing through the centers of the two micro imaging devices in the rotor radial direction and the edge of the rotor as a tangent point.

In some embodiments, a three-point coordinate method is used for locating the pixels. Specifically, the pixel location is performed by a coordinate method, so as to obtain the coordinates of the difference pixel in the difference parameter image, which may specifically include: taking the intersection point of the straight line passing through the centers of the two miniature camera devices in the radial direction of the rotor and the edge of the rotor as a tangent point to make a tangent line of the rotor, taking the intersection point of the two tangent lines as a coordinate origin, and taking the two tangent lines as an x axis and a y axis respectively to establish a coordinate system; and determining the coordinates of the difference pixel points by a three-point cooperation coordinate method based on the coordinate origin and the coordinates of the two miniature camera devices.

Referring to fig. 3, the front micro-camera a and the upper camera E are regarded as a cube, a rotor tangent line is made by taking an intersection point of a straight line passing through the center of the front micro-camera a in the radial direction of the rotor and the edge of the rotor as a tangent point, a rotor tangent line is made by taking an intersection point of a straight line passing through the center of the upper micro-camera E and the edge of the rotor as a tangent point (or the front micro-camera D and the upper camera F are the same in principle), an intersection point of two tangent lines at one point O is regarded as an origin of coordinates, and the two tangent lines are respectively regarded as an x axis and a y axis.

Fig. 16 is a schematic view of the front micro-camera a and the upper micro-camera E in relation to the rotor position. As shown in fig. 16, when viewed from the arrow direction, point 2 is an intersection point of a straight line passing through the center of the front micro-camera a in the radial direction of the rotor (alternatively, the straight line passes through the lens center of the front micro-camera a) and the edge of the rotor 1, i.e., a tangent point; the point 3 is an intersection point of a straight line passing through the center of the front micro camera E in the radial direction of the rotor and the edge of the rotor 1, namely a tangent point. The actual situation is shown in fig. 16: in order to obtain the area of coincidence with the rotor from the top view of the camera, one point at the edge of the rotor is a tangent point.

FIG. 11 is a simplified schematic diagram of three-point coordinate method for locating pixel points. As shown in fig. 11, M, N is a micro-camera with a magnetic bearing system, and its coordinates are: m (M,0), N (0, N), O (0, 0). Any acquired pixel point coordinate is recorded as Q (x, y), the angles of the coordinate with respect to M, N and O are recorded as β 1, β 2, β 3, and according to the relationship shown in fig. 11:

the simultaneous first formula and the second formula are used for determining the position of a target pixel point for one time, and the method comprises the following steps:

simultaneous equations (II) and (III), performing secondary position determination on target pixel points, including:

combining formula I and formula III, determining the position of a target pixel point for three times, including:

and according to the third position determination result, the position determination of the target pixel point is realized, and the coordinate of the point Q:

theoretically, the positions of target pixel points can be determined by using two micro cameras, and the results are equal under ideal conditions of the fourth, fifth and sixth modes. However, in practical situations, the rotor of the magnetic suspension bearing rotates at high speed, which causes the quality change (0-1/1-0) at a fine pixel point of a rotor image, so that a coordinate origin is introduced to participate in position determination and further improve the accuracy.

And S1232, determining the position information of the rotor according to the obtained difference pixel point coordinates in the difference parameter image.

Optionally, the position information includes at least one of a rotor displacement amount, a rotor bending amount, and a rotor elongation amount. The coordinates of the difference pixel points determined by the three-point cooperation coordinate method are preferably suitable for determining the rotor displacement; for other position information, coordinate systems of other planes can be established according to requirements, and then the coordinates of pixel points of images acquired by the camera in the other planes are determined. For example, when the rotor bending amount is determined, the determination is made according to the coordinates of pixel points in the image acquired by the camera B, C; when the elongation of the rotor is determined, the elongation can be determined according to the coordinates of the image pixel points acquired by the camera A, D, or according to the coordinates of the image pixel points acquired by the camera E, F.

The following respectively describes specific ways of determining the rotor displacement, the rotor bending and the rotor elongation of the rotor according to the obtained coordinates of the differential pixel points in the differential parameter image:

(1) rotor displacement amount:

and determining the maximum offset of the rotor in the x-axis direction and the y-axis direction according to the obtained difference pixel point coordinates in the difference parameter image, and calculating the rotor displacement according to the maximum offset of the rotor in the x-axis direction and the y-axis direction.

An image of the rotor position shift is shown with reference to fig. 6. For example, a difference parameter image of the rotor position deviation and the rotor standard suspension position in the actual magnetic bearing system operation is obtained, and the rotor displacement can be obtained by determining the maximum deviation of the rotor in the x direction and the y direction and calculating according to the pythagorean theorem. According to the coordinates of each difference pixel point in the difference parameter image, the maximum deviation of the rotor in the x direction and the y direction can be determined, and the rotor displacement can be obtained by calculation according to the pythagorean theorem.

(2) Rotor bending amount:

determining the maximum displacement of the rotor which is bent according to the obtained difference pixel point coordinates in the difference parameter image to be used as the bending amount of the rotor; for convenience of description, the rotor is viewed in a front view as a straight line, and the principle of the rotor when bending occurs can be described with reference to fig. 7. And determining the maximum displacement in the difference parameter image of the rotor bending and the standard suspension position of the rotor during the actual magnetic bearing system operation according to the coordinates of each difference pixel point in the difference parameter image, namely the rotor bending amount delta x. The image of the rotor actually acquired by the micro-camera is shown in fig. 8, and the maximum displacement in the difference parameter image between the rotor bending and the standard suspension position of the rotor during the actual operation of the magnetic bearing system is Δ x.

(3) Rotor elongation:

and according to the obtained difference pixel point coordinates in the difference parameter image, the rectangular widths of the lateral sides at the two ends of the rotor and the lateral sides at the two ends of the standard suspension position of the rotor are used as the rotor elongation. An image of the rotor elongation actually acquired by the micro-camera is shown in fig. 9, and the width of a rectangle in the differential parameter image between the two end sides of the rotor and the two end sides of the standard suspension position of the rotor in the actual operation of the magnetic bearing system is determined according to the coordinates of each differential pixel point in the differential parameter image, namely the rotor elongation. And obtaining a difference image according to the image after the rotor is stretched and the rotor standard position image, wherein when the rotor is stretched only (namely the situation shown in FIG. 9), the obtained difference image is a rectangular area, and the rotor stretching amount can be obtained by obtaining the rectangular width.

For the purpose of clearly illustrating the technical solution of the present invention, the following describes the execution flow of the magnetic bearing rotor position detection method provided by the present invention with some specific embodiments.

FIG. 12 is a schematic diagram of a magnetic bearing rotor position detection method according to an embodiment of the present invention. As shown in fig. 12, to determine the position detection logic using the ten-thousandth table:

the method comprises the steps of recording a standard suspension position of a rotor in advance, setting an initial area image of the rotor, initializing DSP parameters, acquiring a target area image by a micro camera, identifying image pixel points, carrying out numerical value conversion processing by a DSP (digital signal processor), identifying the positions of the acquired image pixel points as 1 and the positions of the acquired image pixel points as 0, comparing the difference of the target area image to obtain a difference parameter image, directly measuring by a ten-thousandth-of-ten-minute (ten-thousandth-of-ten-minute) meter probe to obtain position information, and finishing one measurement.

FIG. 13 is a schematic diagram of a magnetic bearing rotor position detection method according to another embodiment of the present invention. As shown in fig. 13, the location detection logic is based on a determination;

the method comprises the steps of recording a standard suspension position of a rotor in advance, setting an initial area image of the rotor, initializing DSP parameters, obtaining a target area image by a micro camera, identifying image pixel points, carrying out numerical value conversion processing through the DSP, identifying the positions of the obtained image pixel points as 1 and the positions of the obtained image pixel points as 0, comparing the difference of the target area image to obtain a difference parameter image, determining the coordinates of the pixel points of the difference parameter image, and processing the coordinate parameters through the DSP to obtain position information, namely completing one-time measurement.

Fig. 14 is a block diagram of an embodiment of a magnetic bearing rotor position detection apparatus provided by the present invention. As shown in fig. 14, the apparatus 100 includes an acquisition unit 110 and a determination unit 120.

The collecting unit 110 is configured to collect an image of the rotor of the magnetic suspension bearing through the miniature camera device to obtain a rotor image of a target area.

The determining unit 120 is configured to compare the rotor image of the target area acquired by the acquiring unit 110 with the standard rotor levitation position image of the target area, so as to determine the position information of the rotor.

Fig. 15 is a block diagram showing a configuration of one embodiment of the determination unit. As shown in fig. 15, the determination unit 120 includes an identification subunit 121, a comparison subunit 122, and a determination subunit 123.

The identifying subunit 121 is configured to identify image pixels in the rotor image of the target area, and perform a numerical conversion on the image pixels.

Specifically, the identifying subunit 121 identifies the positions where the image pixels are obtained as 1, identifies the positions where the image pixels are not obtained as 0, identifies the pixel value of each pixel as 0 to 255, and changes the image into a digital matrix during image storage, that is, stores the image through the pixels, where 0 is pure black and 255 is pure white. The invention simplifies the process, and records the position of the acquired image pixel as 1 and the position of the pixel which is not acquired as 0. For example, the acquired rotor image of the target region is subjected to a numerical value conversion process by the DSP, and the positions where the image pixel points are acquired are identified as a numerical value 1, and the positions where the image pixel points are not acquired are identified as a numerical value 0, which can refer to the schematic diagram of the principle of image pixel point conversion shown in fig. 5.

The comparison subunit 122 is configured to compare the converted rotor image of the target area with the standard rotor levitation position image to obtain a difference parameter image.

The determining subunit 123 is configured to determine the position information of the rotor according to the difference parameter image obtained by the comparison.

In one embodiment, the determining subunit 123 measures the difference parameter image to obtain the position information of the rotor. More specifically, the determining subunit 123 measures the difference parameter image through a ten-thousandth meter to obtain the position information of the rotor, for example, a digital ten-thousandth meter D62S may be used, and the parameters of the digital ten-thousandth meter are shown in table 1, so that the precision of the digital ten-thousandth meter reaches 0.1um, the suspension error precision condition of the magnetic suspension bearing is met, the calibration micro-measurement of horizontal and vertical displacements of the difference parameter image can be directly performed, and further the position information can be obtained.

D62S digital display ten-thousandth meter

TABLE 1

Optionally, the position information includes at least one of a rotor displacement amount, a rotor bending amount, and a rotor elongation amount. The target areas corresponding to different position information are different. For example, for the rotor displacement, the target region may be set as the two end regions of the rotor, i.e., the region image of any one of the two ends of the rotor may be acquired; for the amount of rotor bending, the target region may be set to a middle region of the rotor, preferably a region axially midway along the side of the rotor. For the rotor elongation, the target area can be set as the two end areas of the rotor, i.e. images of the two end areas of the rotor can be acquired.

(1) rotor displacement amount:

(2) Rotor bending amount:

(3) Rotor elongation:

In another specific embodiment, the determining subunit 123 determines the position information of the rotor by a coordinate method based on the difference parameter image. Fig. 10 is a flowchart illustrating a step of determining position information of the rotor by a coordinate method based on the difference parameter image according to an embodiment of the present invention.

As shown in fig. 10, step S123 includes step S1231 and step S1232.

Fig. 16 is a schematic view of the front micro-camera a and the upper micro-camera E in relation to the rotor position. As shown in fig. 16, when viewed from the arrow direction, point 2 is an intersection point of a straight line passing through the lens center of the front micro-camera a in the rotor radial direction (alternatively, the straight line passes through the lens center of the front micro-camera a) and the edge of the rotor 1, that is, a tangent point; the point 3 is an intersection point of a straight line passing through the center of the front micro camera E in the radial direction of the rotor and the edge of the rotor 1, namely a tangent point. The actual situation is shown in fig. 16: in order to obtain the area of coincidence with the rotor from the top view of the camera, one point at the edge of the rotor is a tangent point.

(1) rotor displacement amount:

and determining the maximum offset of the rotor in the x-axis direction and the y-axis direction according to the obtained difference pixel point coordinates in the difference parameter image, and calculating the rotor displacement according to the maximum offset of the rotor in the x-axis direction and the y-axis direction. An image of the rotor position shift is shown with reference to fig. 6. For example, a difference parameter image of the rotor position deviation and the rotor standard suspension position in the actual magnetic bearing system operation is obtained, and the rotor displacement can be obtained by determining the maximum deviation of the rotor in the x direction and the y direction and calculating according to the pythagorean theorem. According to the coordinates of each difference pixel point in the difference parameter image, the maximum deviation of the rotor in the x direction and the y direction can be determined, and the rotor displacement can be obtained by calculation according to the pythagorean theorem.

(2) Rotor bending amount:

(3) Rotor elongation:

The invention also provides a storage medium corresponding to the magnetic bearing rotor position detection method, and a computer program is stored on the storage medium, and when the computer program is executed by a processor, the computer program realizes the steps of any one of the methods.

The invention also provides a magnetic bearing controller corresponding to the magnetic bearing rotor position detection method, which comprises a processor, a memory and a computer program stored in the memory and capable of running on the processor, wherein the processor realizes the steps of any one of the methods when executing the program.

The invention also provides a magnetic suspension bearing controller corresponding to the magnetic suspension bearing rotor position detection device, which comprises any one of the magnetic suspension bearing rotor position detection devices.

Accordingly, according to the scheme provided by the invention, the miniature camera device is used for carrying out image acquisition on the rotor of the magnetic suspension bearing to obtain the rotor image of the target area, so that the acquired rotor image of the target area is compared with the standard rotor suspension position image of the target area to determine the position information of the rotor. The non-contact measurement method capable of replacing the displacement sensor obtains a rotor image through a plurality of miniature cameras, carries out digital processing, compares the rotor image with a standard value and further accurately determines whether the rotor is bent or displaced in the axial direction and the radial direction and the size of the position change quantity of the rotor; the method for determining the pixel points by using the universal meter to replace the coordinates improves the measurement precision of the related technology.

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope and spirit of the invention and the following claims. For example, due to the nature of software, the functions described above may be implemented using software executed by a processor, hardware, firmware, hardwired, or a combination of any of these. In addition, each functional unit may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit.

In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.

The units described as separate parts may or may not be physically separate, and the parts serving as the control device may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A magnetic bearing rotor position detection method, wherein a miniature camera device is arranged in the magnetic bearing, the method comprising:

acquiring an image of a rotor of the magnetic suspension bearing through the miniature camera device to obtain a rotor image of a target area;

and comparing the acquired rotor image of the target area with the standard rotor suspension position image of the target area to determine the position information of the rotor.

2. The method of claim 1, wherein comparing the acquired rotor image of the target area with a standard rotor levitation position image of the target area to determine the position information of the rotor comprises:

identifying image pixel points in the rotor image of the target area, and carrying out numerical conversion on the image pixel points;

comparing the rotor image of the target area obtained after conversion with the rotor standard suspension position image to obtain a difference parameter image;

and determining the position information of the rotor according to the difference parameter image obtained by comparison.

3. The method of claim 2,

comparing the rotor image obtained after conversion with the rotor standard suspension position image to obtain a difference parameter image, wherein the difference parameter image comprises:

carrying out AND operation on the values of the rotor image obtained after conversion and the corresponding position in the rotor standard suspension position image of the target area to obtain a difference pixel point, thereby obtaining a difference parameter image;

and/or the presence of a gas in the gas,

determining the position information of the rotor according to the difference parameter image obtained by comparison, wherein the step of determining the position information of the rotor comprises the following steps:

measuring the difference parameter image to obtain the position information of the rotor;

and/or the presence of a gas in the gas,

and determining the position information of the rotor by a coordinate method based on the difference parameter image.

4. The method of claim 3, wherein the positional information includes at least one of rotor displacement, rotor bending, and rotor elongation,

measuring the difference parameter image to obtain position information of the rotor, including:

measuring the maximum offset of the rotor in the x-axis direction and the y-axis direction on the difference parameter image through the ten-thousandth meter probe so as to calculate the rotor displacement according to the maximum offset of the rotor in the x-axis direction and the y-axis direction;

and/or the presence of a gas in the gas,

measuring the maximum displacement of the rotor bending on the difference parameter image through the ten-thousandth meter probe to serve as the rotor bending amount;

and/or the presence of a gas in the gas,

and measuring the rectangular widths of the lateral sides at the two ends of the rotor and the lateral sides at the two ends of the standard suspension position of the rotor on the difference parameter image through the universal meter probe to serve as the elongation of the rotor.

5. The method of claim 3, wherein determining the position information of the rotor by a coordinate method based on the difference parameter image comprises:

based on the difference parameter image, carrying out pixel point positioning by a coordinate method to obtain a difference pixel point coordinate in the difference parameter image;

and determining the position information of the rotor according to the obtained difference pixel point coordinates in the difference parameter image.

6. The method of claim 5, wherein the positional information includes at least one of rotor displacement, rotor bending, and rotor elongation;

determining the position information of the rotor according to the obtained difference pixel point coordinates in the difference parameter image, wherein the determining comprises the following steps:

determining the maximum offset of the rotor in the x-axis direction and the y-axis direction according to the obtained difference pixel point coordinates in the difference parameter image, and calculating the rotor displacement according to the maximum offset of the rotor in the x-axis direction and the y-axis direction;

and/or the presence of a gas in the gas,

determining the maximum displacement of the rotor which is bent according to the obtained difference pixel point coordinates in the difference parameter image to be used as the bending amount of the rotor;

and/or the presence of a gas in the gas,

and according to the obtained difference pixel point coordinates in the difference parameter image, the rectangular widths of the lateral sides at the two ends of the rotor and the lateral sides at the two ends of the standard suspension position of the rotor are used as the rotor elongation.

7. The method according to claim 5 or 6, characterized in that a rotor image of the target area is acquired by two micro cameras, on the cross section of the rotor in the radial direction, straight lines in the radial direction respectively passing through the centers of the two micro cameras and the edge of the rotor respectively form two intersection points, and rotor tangent lines passing through the two intersection points are perpendicular to each other;

carrying out pixel point positioning by a coordinate method to obtain the coordinate of the difference pixel point in the difference parameter image, wherein the method comprises the following steps:

taking the intersection point of the straight line passing through the centers of the two miniature camera devices in the radial direction of the rotor and the edge of the rotor as a tangent point to make a tangent line of the rotor, taking the intersection point of the two tangent lines as a coordinate origin, and taking the two tangent lines as an x axis and a y axis respectively to establish a coordinate system;

and determining the coordinates of the difference pixel points by a three-point cooperation coordinate method based on the coordinate origin and the coordinates of the two miniature camera devices.

8. A magnetic bearing rotor position detection apparatus, wherein a miniature camera device is arranged in the magnetic bearing system, the apparatus comprising:

the acquisition unit is used for acquiring an image of the rotor of the magnetic suspension bearing through the miniature camera device to obtain a rotor image of a target area;

and the determining unit is used for comparing the rotor image of the target area acquired by the acquiring unit with the standard rotor suspension position image of the target area so as to determine the position information of the rotor.

9. The apparatus of claim 8, wherein the determining unit comprises:

the identification subunit is used for identifying image pixel points in the rotor image of the target area and carrying out numerical conversion on the image pixel points;

the comparison subunit is used for comparing the rotor image of the target area obtained after conversion with the rotor standard suspension position image to obtain a difference parameter image;

and the determining subunit is used for determining the position information of the rotor according to the difference parameter image obtained by comparison.

10. The apparatus of claim 9,

the comparison subunit compares the rotor image obtained after conversion with the rotor standard suspension position image to obtain a difference parameter image, and the comparison subunit includes:

and/or the presence of a gas in the gas,

the determining subunit determines, according to the difference parameter image obtained by the comparison, position information of the rotor, including:

and/or the presence of a gas in the gas,

11. The apparatus of claim 10, wherein the positional information includes at least one of a rotor displacement amount, a rotor bending amount, and a rotor elongation amount,

the determining subunit measures the difference parameter image to obtain position information of the rotor, and includes:

and/or the presence of a gas in the gas,

12. The apparatus of claim 10, wherein the determining the stator unit determines the position information of the rotor by a coordinate method based on the difference parameter image, comprising:

13. The apparatus of claim 12, wherein the positional information includes at least one of a rotor displacement amount, a rotor bending amount, and a rotor elongation amount;

the determining subunit determines, according to the obtained difference pixel point coordinates in the difference parameter image, the position information of the rotor, including:

and/or the presence of a gas in the gas,

14. The device according to claim 12 or 13, wherein the rotor image of the target area is acquired by two micro cameras, on the cross section of the rotor in the radial direction, two intersection points are respectively formed by straight lines in the radial direction passing through the centers of the two micro cameras and the edge of the rotor, and rotor tangent lines passing through the two intersection points are mutually perpendicular;

the determining subunit performs pixel location by a coordinate method to obtain a difference pixel coordinate in the difference parameter image, including:

15. A storage medium, having stored thereon a computer program which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 7.

16. A magnetic bearing controller comprising a processor, a memory and a computer program stored on the memory and executable on the processor, the processor when executing the program implementing the steps of the method as claimed in any one of claims 1 to 7, comprising a magnetic bearing rotor position sensing device as claimed in any one of claims 8 to 14.

17. A magnetic bearing system, comprising: the magnetic bearing controller of claim 16.