CN108645602B - System and method for comprehensively measuring blade tip clearance and blade rotating speed of rotary machine and image processing program - Google Patents
System and method for comprehensively measuring blade tip clearance and blade rotating speed of rotary machine and image processing program Download PDFInfo
- Publication number
- CN108645602B CN108645602B CN201810255783.6A CN201810255783A CN108645602B CN 108645602 B CN108645602 B CN 108645602B CN 201810255783 A CN201810255783 A CN 201810255783A CN 108645602 B CN108645602 B CN 108645602B
- Authority
- CN
- China
- Prior art keywords
- image
- rotating speed
- gap
- image acquisition
- gray
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000000034 method Methods 0.000 title claims abstract description 65
- 238000005259 measurement Methods 0.000 claims abstract description 55
- 238000012545 processing Methods 0.000 claims abstract description 34
- 238000004364 calculation method Methods 0.000 claims abstract description 3
- 238000007781 pre-processing Methods 0.000 claims description 61
- 238000004891 communication Methods 0.000 claims description 19
- 230000009466 transformation Effects 0.000 claims description 19
- 230000008569 process Effects 0.000 claims description 17
- 238000005070 sampling Methods 0.000 claims description 8
- 230000009467 reduction Effects 0.000 claims description 6
- 230000001960 triggered effect Effects 0.000 claims description 6
- 238000000605 extraction Methods 0.000 claims description 5
- 238000003491 array Methods 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 description 6
- 238000010586 diagram Methods 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000011112 process operation Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000007405 data analysis Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000003745 diagnosis Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 238000010183 spectrum analysis Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M13/00—Testing of machine parts
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D21/00—Measuring or testing not otherwise provided for
- G01D21/02—Measuring two or more variables by means not covered by a single other subclass
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Image Analysis (AREA)
Abstract
The invention discloses a system and a method for comprehensively measuring the tip clearance and the blade rotating speed of a rotary machine and an image processing program, which can achieve the effect of measuring the tip clearance and the blade rotating speed only by using a high-frequency image collector. The invention comprises an image collector, an image acquisition card and an image processing unit; the image collector is used for collecting real-time images of the rotating blade and the casing and transmitting the real-time images to the image collecting card; the image acquisition card is used for converting the received signals into digital signals and transmitting the digital signals to the image processing unit; the image processing unit is used for carrying out image processing and calculation on the received image and obtaining the blade tip clearance and the blade rotating speed of the detected rotating impeller. The method has the advantages of accurate measurement, small quantity of sensors required by measurement, capability of being used for measuring the clearance and the rotating speed of the rotating mechanical blade in real time, and wide application prospect.
Description
Technical Field
The invention relates to the technical field of measurement, in particular to a system and a method for comprehensively measuring a rotating machinery blade tip clearance and a blade rotating speed and an image processing program.
Background
The blade tip clearance of a rotating machine blade generally refers to the radial distance between the rotating machine rotor blade and a casing, the rotating speed of the rotating machine generally refers to the number of turns of the rotating machine rotating around the circle center in unit time, and the blade tip clearance and the rotating speed are two important parameters influencing the performance of the rotating machine. Taking a typical rotary machine, namely an aircraft engine as an example, when the blade tip clearance of the aircraft engine is too large, the pressure ratio of a gas compressor is reduced, the oil consumption is increased, and the efficiency of the engine is also greatly reduced. However, when the blade tip clearance is too small, the blade is heated to expand in a high-temperature environment, so that friction may be generated between the blade tip and the inner wall of the casing, parts are damaged, and the safety of the engine is affected; meanwhile, the strength of the blades of the engine and the temperature before the turbine are determined by the rotating speed of the aircraft engine, and the thrust of the engine is approximately proportional to the third power of the rotating speed, so that the rotating speed is the most basic and important control quantity of the aircraft engine in terms of safe operation of the engine and comprehensive performance of the engine. In conclusion, the reasonable design and the monitoring of the blade tip clearance and the blade rotating speed of the engine have important significance for improving the performance of the engine. There are some examples of using image processing technology for gap measurement and rotation speed measurement of a rotating machine, respectively, but there are some disadvantages and problems, and there is no example of a method that can organically combine gap measurement and rotation speed measurement based on image processing technology.
Chinese patent 201210455748.1 discloses a method and system for measuring engine blade tip clearance, the method is characterized in that images of a casing and blade tips are shot by a graph collector, and the clearance between the blade tips of each blade of the engine and the casing is obtained by data analysis of an upper computer; meanwhile, according to an angle sensor arranged on the rotating shaft, angle information corresponding to the relevant gap value is measured in time; and finally, according to the camera calibration information, completing the conversion between the pixel point and the physical distance. But this method requires two sensors, a camera and an angular velocity sensor. The angular velocity sensor is arranged on the shaft, is in contact measurement and has some problems, and is only suitable for a low rotating speed range and cannot measure a high rotating speed object; if communication faults occur between different sensors or communication rates are different, the angle information of the measured gap value cannot be determined; and the method is only directed to gap measurements.
Chinese patent 200610029122.9 discloses a "rotational speed measuring device based on computer vision", which uses a vision collecting device to collect the motion blurred image of the object to be measured mounted on the speed measuring platform, and transmits the obtained blurred image information to the computer system. And extracting the rotating speed value of the object to be measured by performing operations such as motion dimension reduction processing, time-frequency transformation, frequency spectrum analysis, motion parameter acquisition and the like on the blurred image. However, the method is only suitable for the condition of low rotating speed, and according to the Shannon sampling law, when the rotating speed of the measured object is high, the method generates distortion in measurement; and the method is only directed to rotational speed measurements.
Because the high-frequency images of the rotor of the rotary machine contain a large amount of information including the blade tip clearance and the rotor rotating speed, the development of a rotary machine blade tip clearance and blade rotating speed comprehensive measurement system based on an image processing technology is feasible. Through processing the single frame image, the related information of the rotor blade tip clearance can be extracted; through the processing of a series of images with time marks, the related information of the rotor speed can be extracted. In order to reduce the number and the weight of the rotating machinery sensors and achieve the aim of measuring various variables by a single sensor, the invention provides a rotating machinery blade tip clearance and blade rotating speed comprehensive measuring system based on an image processing technology.
Disclosure of Invention
The invention aims to provide a system and a method for comprehensively measuring the tip clearance and the blade rotating speed of a rotary machine based on an image processing technology and an image processing program, which can simultaneously measure the tip clearance and the rotating speed of the rotary machine by using only one high-frequency image collector. The device has the advantages of simple structure, convenience in installation and use, high measurement precision, capability of measuring the tip clearance and the rotating speed of the rotating machinery in real time and wide development prospect.
The invention adopts the following technical scheme for realizing the purpose:
a rotating machinery tip clearance and blade rotational speed comprehensive measurement system, including image collector, image acquisition card, image processing unit; the image collector is used for collecting real-time images of the blade tip part and the casing of the rotating blade and transmitting the images to the image collecting card; the image acquisition card is used for converting the received signals into digital signals and transmitting the digital signals to the image processing unit; the image processing unit is used for carrying out image processing and calculation on the received image and obtaining the blade tip clearance and the blade rotating speed of the detected rotating impeller.
Preferably, the sampling frequency of the image collector meets the Shannon sampling theorem, that is, at least one image can be collected per secondAnd (4) frame images, wherein N is the rotating speed of the rotating machine, and X is the number of blades arranged on the rotating machine.
Preferably, the image processing unit comprises an image acquisition and preprocessing module, a rotating speed measuring module and a gap measuring module; the image acquisition and preprocessing module converts each frame of RGB image acquired by the image acquisition device into a gray image, and a data queue is formed by the gray value of a specific pixel point in each frame of gray image and the time of the image acquisition and preprocessing module receiving the frame of gray image, wherein the specific pixel point is any pixel point of the blade tip part of the blade in the image acquired by the image acquisition device, and the data queue is sent to the rotating speed measuring module; the rotating speed measuring module processes and calculates the received data queue to obtain a rotating speed value of the rotating machine; the image acquisition and preprocessing module monitors the communication between the image acquisition and preprocessing module and the rotating speed measuring module in real time, when the gray value changes suddenly, a communication queue is triggered, and the image acquisition and preprocessing module sends the currently acquired single-frame gray image to the gap measuring module; and the gap measurement module processes and calculates the received single-frame gray level image to obtain the physical width of the gap.
Preferably, the image processing unit further comprises an image display module; the image acquisition and preprocessing module transmits acquired images to the image display module in real time, the rotating speed measurement module transmits a calculated rotating speed value to the image display module, and the gap measurement module transmits a calculated gap physical width to the image display module; the image display module displays a video image containing gap position, physical width and rotating speed information.
A method for comprehensively measuring the tip clearance and the blade rotating speed of a rotary machine comprises the following steps:
step 1: the image collector calibrates the corresponding relation between the physical width of the gap and the pixel value of the gap width to obtain calibration information;
step 2: the image collector collects real-time images of the blade tip part and the casing of the rotating blade and transmits the images to the image collection card;
and step 3: the image acquisition card converts the received signals into digital signals and transmits the digital signals to the image acquisition and preprocessing module;
and 4, step 4: the image acquisition and preprocessing module converts each frame of RGB image acquired by the image acquisition device into a gray image, and takes the gray value of a specific pixel point in each frame of gray image and the time of the image acquisition and preprocessing module receiving the frame of gray image to form a data queue and sends the data queue to the rotating speed measuring module;
and 5: the rotating speed measuring module processes and calculates the received data to obtain a rotating speed value of the rotating machine;
step 6: the image acquisition and preprocessing module monitors communication between the image acquisition and preprocessing module and the rotating speed measuring module in real time, when the gray value changes suddenly, a communication queue is triggered, the image acquisition and preprocessing module sends a currently acquired single-frame gray image to the gap measuring module, the gap measuring module processes and calculates the received single-frame gray image to obtain a pixel value of the gap width, then the image acquisition and preprocessing module accesses the image acquisition device to obtain calibration information, and the physical width of the gap corresponding to the pixel value of the gap width is found, so that the physical width of the gap is obtained.
Preferably, the step of calculating the rotation speed by the rotation speed measuring module in step 5 includes:
step 5.1: setting a rotating speed value updated every T moment, and dividing a data queue sent by the image acquisition and preprocessing module into arrays [ (h) with the time length of Ta,ta),(ha+1,ta+1),…,(hb,tb)]Wherein t isb-taT is approximately distributed; a and b represent the index of the first and last array in the data queue, respectively;
step 5.2: extracting the gray values in the array to form a gray array [ ha,ha+1,…,hb]；
Step 5.3: take the sampling time asCarrying out fast Fourier transform on the gray array, and extracting the frequency f corresponding to the maximum amplitude;
step 5.4: obtaining a rotating speed value N according to the frequency f and the number X of the blades,
preferably, the step of calculating the physical width of the tip clearance by the clearance measurement module in step 6 includes:
step 6.1: carrying out noise reduction processing on the single-frame gray level image to obtain an image with high signal-to-noise ratio;
step 6.2: performing edge extraction on the image to obtain an edge image;
step 6.3: hough transformation (Hough transformation) is carried out on the edge image, and the threshold value of the Hough transformation is continuously increased until the Hough transformation only returns two parallel or approximately parallel straight lines;
step 6.4: calculating the pixel value of the gap according to the linear information returned by Hough transformation;
the Hough transform returns information of a straight line: [ [ d ]l1,θl1],[dl2,θl2]]
d is the intercept, the unit is the pixel value, theta is the angle; subscript l1 is a first line and subscript l2 is a second line.
The pixel value is then:
wherein: Δ θ ═ θl1-θl2。
Step 6.5: and finding the physical width of the gap corresponding to the pixel value of the gap according to the calibration information to obtain the physical width of the gap.
An image processing program comprises a main process, an image acquisition and preprocessing sub-process, a rotating speed measurement sub-process and a gap measurement sub-process; the main process creates each subprocess and a communication queue between the subprocesses; the image acquisition and preprocessing subprocess converts each received frame of RGB image into a gray image, takes the gray value of a specific pixel point in each frame of gray image and the time of the image acquisition and preprocessing subprocess receiving the frame of gray image to form a data queue, and sends the data queue to the rotational speed measurement subprocess; the rotation speed measurement quantum process carries out fast Fourier transform on the received data to obtain a frequency value, and carries out frequency-rotation speed conversion to obtain a rotation speed value of the rotary machine; the image acquisition and preprocessing subprocess monitors the communication between the image acquisition and preprocessing subprocess and the rotating speed measurement subprocess in real time, when the gray value changes suddenly, a communication queue is triggered, and the image acquisition and preprocessing subprocess sends the currently acquired single-frame gray image to the gap measurement subprocess; the gap measurement quantum process carries out noise reduction, edge extraction, Hough transformation and other processing on the received single-frame gray level image, firstly calculates the pixel value of the gap, and then obtains the physical width of the gap by combining the corresponding relation between the pixel value of the gap and the physical width of the gap.
Preferably, the method further comprises an image display sub-process; the communication among the image acquisition and preprocessing subprocess, the rotating speed measurement subprocess, the gap measurement subprocess and the image display subprocess is respectively as follows: the image acquisition and preprocessing subprocess transmits acquired images to the image display subprocess in real time, the rotation speed measurement subprocess sends a calculated rotation speed value to the image display subprocess, and the gap measurement subprocess sends a calculated gap physical width to the image display subprocess; and the image display subprocess displays a video image containing gap position, physical width and rotating speed information.
Has the advantages that:
the invention is a rotating machinery blade tip clearance and blade rotating speed comprehensive measurement system based on the image processing technology, and can simultaneously measure the blade tip clearance and the rotating speed of the rotating machinery by using only one high-frequency image collector, thereby reducing the number and the weight of rotating machinery sensors and realizing the aim of measuring various variables by using a single sensor.
Secondly, the computer image processing program adopts a multi-process operation mode, on one hand, the multi-process operation mode can utilize the computing power of a computer processor to the maximum extent, can greatly improve the image processing speed and simultaneously provides convenience for the parallel computing of multiple processors; on the other hand, the multi-process operation mode is beneficial to the expansion application of the image processing program, for example, if the blade vibration measurement is expanded on the basis of blade tip clearance and blade rotation speed measurement, only a subprocess of the blade vibration measurement needs to be compiled, and an interface and a communication queue are defined, so that the subprocess can be directly added into the computer image processing program.
Thirdly, the invention can display the image of the measured leaf disc on the computer in real time, and the user can monitor the operation condition of the measured leaf disc, and if an accident happens, the user can carry out preliminary fault diagnosis through the image displayed in real time.
Drawings
Fig. 1 is a schematic diagram of an image acquisition structure.
Fig. 2 is a diagram of a computer image processing program.
In fig. 1, the list of components represented by the various reference numbers is as follows:
1: a computer; 2: an image acquisition card; 3: a high-frequency image collector; 4: rotating the mechanical case; 5: a rotating machine blade; 6: and a data line.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention are described in further detail below with reference to the accompanying drawings.
Fig. 1 shows a schematic diagram of an image acquisition structure of the present invention, which includes: the high-frequency image collector 3 can be a CCD camera or other types of image collectors, and the high-frequency image collector 3 is used for collecting high-frequency images of a rotating blade and a casing of the rotating machine; and the image acquisition card 2 is used for converting the image acquired by the high-frequency image acquirer 3 into a digital signal, and transmitting the digital signal to the computer 1 through a computer bus in real time for further processing.
When the method is specifically implemented, a high-frequency image collector is installed, relevant initial parameters are set, the high-frequency image collector can obtain clear images, and a computer can receive digital signals converted by an image acquisition card; and calibrating the high-frequency image collector to obtain the relationship between the pixel point and the physical distance. The physical distance refers to the physical width of the gap (the gap between the blade tip and the casing). For example, when the physical gaps are 1mm, 2mm, 3mm, and …, respectively, in the images acquired by the high-frequency image acquirer, the pixel values of the gap widths are 20, 40, 60, and …, respectively. Calibration information can be derived from this relationship.
FIG. 2 is a diagram of a computer image processing program structure according to the present invention, and as shown in FIG. 2, a main process of the computer image processing program creates sub-processes and inter-process communication queues. The sub-process (I) is an image acquisition and preprocessing sub-process and is used for driving a high-frequency image acquisition device to acquire a high-frequency image and simply preprocessing the high-frequency image; the shown subprocess is a rotating speed measuring subprocess and is used for carrying out fast Fourier transform on the received data to obtain a frequency value, and carrying out frequency-rotating speed conversion to obtain a rotating speed value of the rotating machine; the sub-process (c) is a gap measurement sub-process, and is used for performing noise reduction, edge extraction, Hough transformation and other processing on the received single-frame image, firstly calculating the pixel value of the gap, and then converting the pixel value by combining with the calibration information to obtain the physical width of the gap; and the subprocess (IV) is an image display subprocess and is used for displaying video images containing gap position, physical width and rotating speed information.
The individual sub-processes are detailed as follows:
1. image acquisition and preprocessing subprocess
The image acquisition and preprocessing subprocess is used for opening a computer data port and receiving image digital signals transmitted to a computer by an image acquisition card. And the format of the image received by the image acquisition and preprocessing subprocess is an RGB format. Because the difference between the gray values of the gap and the edges of the blade and the casing as well as between the edges of the blade and the surfaces of the blade in the gray level image is larger, and the speed of processing the gray level image by the computer is far higher than that of processing the RGB image, the image acquisition and preprocessing subprogram firstly converts the RGB format of the image into the gray level format. And when the image acquisition and preprocessing subprocess receives the image, recording the accurate system time when the image is received, and storing the accurate system time and the image in the same array.
The image acquisition and preprocessing sub-process is in communication with other sub-processes. And when the image acquisition and preprocessing subprocess is communicated with the rotating speed measurement subprocess, forming a data queue by the gray value of a specific pixel point in each frame of image and the system time corresponding to each frame of image, and sending the data queue to the rotating speed measurement subprocess. For example, the gray value of the selected pixel point in the ith frame is hiWhen the image acquisition and preprocessing subprocess receives the ith frame of image, the recorded system time is tiThen, the data format transmitted from the image acquisition and preprocessing subprocess to the rotation speed measurement subprocess is as follows: [ (h)1,t1),(h2,t2),…,(hi,ti),…](ii) a When the image acquisition and preprocessing subprocess is communicated with the gap measurement subprocess, the image acquisition and preprocessing subprocess monitors the communication between the image acquisition and preprocessing subprocess and the rotating speed measurement subprocess in real time, when the gray value changes suddenly, the communication queue is triggered, and the image acquisition and preprocessing subprocess sends the currently acquired single-frame gray image to the gap measurement subprocess; and when the image acquisition and preprocessing subprocess is communicated with the image display subprocess, the image acquisition and preprocessing subprocess directly sends the gray format image acquired by the high-frequency image acquisition device to the image display subprocess.
2. Rotational speed measurement quantum process
The rotation speed measuring quantum process receives [ (h) sent by the image acquisition and preprocessing sub-process1,t1),(h2,t2),…,(hi,ti),…]The formatted data. If the user sets the rotating speed value to be updated every T time, the rotating speed measuring subprocess calculates the rotating speed by the following method: first, the data sent by the image acquisition and preprocessing sub-process is divided into arrays of time length T [ (h)a,ta),(ha+1,ta+1),…,(hb,tb)]Wherein t isb-taT is approximately distributed; next, the data in the above array are comparedExtracting gray value to form new array [ h ]a,ha+1,…,hb](ii) a Then taking the sampling time asCarrying out fast Fourier transform on the gray array, and extracting the frequency f corresponding to the maximum amplitude; finally, obtaining a rotating speed value N according to the frequency f and the number X of the blades,
and when the rotation speed measurement sub-process is communicated with the image display sub-process, the rotation speed measurement sub-process sends the calculated rotation speed value to the image display sub-process at a time interval of T.
3. Gap measurement quantum process
When the gray value sent to the rotating speed measurement subprocess by the image acquisition and preprocessing subprocess is suddenly changed, namely hi+1-hi＞hsetTime (h)setAnd the interval measurement subprocess receives the single-frame image sent by the image acquisition and preprocessing subprocess, and adds 1 to the flag bit by itself, and when the flag bit is greater than the number of the leaves, the flag bit is 1. The flag bit is used for determining the leaf corresponding to the single-frame image, for example, when the value of the flag bit is k after the single-frame image sent by the image acquisition and preprocessing sub-process, the single-frame image corresponds to the k-th leaf. The step of calculating the blade tip gap by using the single-frame gray level image in the gap measurement quantum process is as follows: firstly, carrying out noise reduction processing on an image to obtain an image with high signal-to-noise ratio; secondly, performing edge extraction on the image to obtain an edge image; then, by utilizing Hough transformation, continuously improving the threshold value of the Hough transformation until the Hough transformation only returns two parallel or approximately parallel straight lines; then, according to the straight line information returned by Hough transformation, calculating the pixel value of the gap; and finally, calculating the physical width of the gap according to the pixel value of the gap and the calibration information of the high-frequency image collector.
The physical meanings of the two straight lines returned by Hough transformation are the two boundary lines of the gap. The information of the two straight lines returned by the Hough transformation comprises the respective intercepts and angles of the two straight lines, wherein the intercepts of the straight lines take pixel points as units. And combining the angle information of the two straight lines to obtain the pixel value between the two straight lines according to the intercept information.
The Hough transform returns information of a straight line: [ [ d ]l1,θl1],[dl2,θl2]]
d is the intercept, the unit is the pixel value, theta is the angle; subscript l1 is a first line and subscript l2 is a second line.
The pixel values are:
wherein: Δ θ ═ θl1-θl2
In the normal case of thetal1≈θl2I.e., Δ θ ≈ 0,
and when the gap measurement sub-process is communicated with the image display sub-process, the gap measurement sub-process sends the straight line information returned by Hough transformation and the calculated physical width to the image display sub-process.
4. Image display sub-process
The image display subprocess acquires a real-time image acquired by the high-frequency image acquirer from the image acquisition and preprocessing subprocess, acquires a rotating speed value from the rotating speed measurement subprocess, and acquires linear position information and physical width from the gap measurement subprocess. The image display sub-process has the main role of displaying information received from other sub-processes on the computer display.
According to the technical scheme disclosed by the embodiment, only a single high-frequency image collector can be used, and the blade tip clearance and the blade rotating speed of the rotary machine can be measured on line, so that the method has important significance for reducing the weight of accessories of the rotary machine, ensuring the safe and stable operation of the rotary machine and improving the efficiency of the rotary machine. However, the present invention is not limited thereto, that is, the above-mentioned is only the technical idea of the present invention, and the present invention is not limited thereto, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. A rotating machinery tip clearance and blade rotational speed comprehensive measurement system, wherein including image collector, picture collecting card, image processing unit; the image collector is used for collecting real-time images of the blade tip part and the casing of the rotating blade and transmitting the images to the image collecting card; the image acquisition card is used for converting the received signals into digital signals and transmitting the digital signals to the image processing unit; the image processing unit is used for carrying out image processing and calculation on the received image and obtaining the blade tip clearance and the blade rotating speed of the detected rotating impeller;
the image processing unit comprises an image acquisition and preprocessing module, a rotating speed measuring module and a gap measuring module; the image acquisition and preprocessing module converts each frame of RGB image acquired by the image acquisition device into a gray image, and takes the gray value of a specific pixel point in each frame of gray image and the time of the image acquisition and preprocessing module receiving the frame of gray image to form a data queue, and sends the data queue to the rotating speed measuring module; the rotating speed measuring module processes and calculates the received data queue to obtain a rotating speed value of the rotating machine; the image acquisition and preprocessing module monitors the communication between the image acquisition and preprocessing module and the rotating speed measuring module in real time, when the gray value changes suddenly, a communication queue is triggered, and the image acquisition and preprocessing module sends the currently acquired single-frame gray image to the gap measuring module; and the gap measurement module processes and calculates the received single-frame gray level image to obtain the physical width of the gap.
2. The system of claim 1, wherein the sampling frequency of the image collector satisfies shannon's sampling theorem that at least one image can be collected per secondFrame imageWhere N is the rotational speed of the rotary machine and X is the number of blades mounted on the rotary machine.
3. The system for comprehensively measuring the blade tip clearance and the blade rotating speed of the rotary machine according to claim 1, wherein the image processing unit further comprises an image display module; the image acquisition and preprocessing module transmits acquired images to the image display module in real time, the rotating speed measurement module transmits a calculated rotating speed value to the image display module, and the gap measurement module transmits a calculated gap physical width to the image display module; the image display module displays a video image containing gap position, physical width and rotating speed information.
4. A method for comprehensively measuring the tip clearance and the blade rotating speed of the rotary machine based on the system of claim 1 is characterized by comprising the following steps:
step 1: the image collector calibrates the corresponding relation between the physical width of the gap and the pixel value of the gap width to obtain calibration information;
step 2: the image collector collects real-time images of the blade tip part and the casing of the rotating blade and transmits the images to the image collection card;
and step 3: the image acquisition card converts the received signals into digital signals and transmits the digital signals to the image acquisition and preprocessing module;
and 4, step 4: the image acquisition and preprocessing module converts each frame of RGB image acquired by the image acquisition device into a gray image, and takes the gray value of a specific pixel point in each frame of gray image and the time of the image acquisition and preprocessing module receiving the frame of gray image to form a data queue and sends the data queue to the rotating speed measuring module;
and 5: the rotating speed measuring module processes and calculates the received data to obtain a rotating speed value of the rotating machine;
step 6: the image acquisition and preprocessing module monitors communication between the image acquisition and preprocessing module and the rotating speed measuring module in real time, when the gray value changes suddenly, a communication queue is triggered, the image acquisition and preprocessing module sends a currently acquired single-frame gray image to the gap measuring module, the gap measuring module processes and calculates the received single-frame gray image to obtain a pixel value of the gap width, then the image acquisition and preprocessing module accesses the image acquisition device to obtain calibration information, and the physical width of the gap corresponding to the pixel value of the gap width is found, so that the physical width of the gap is obtained.
5. The method for comprehensively measuring the blade tip clearance and the blade rotating speed of the rotary machine according to claim 4, wherein the step of calculating the rotating speed by the rotating speed measuring module in the step 5 comprises the following steps:
step 5.1: setting a rotating speed value updated every T moment, and dividing a data queue sent by the image acquisition and preprocessing module into arrays [ (h) with the time length of Ta,ta),(ha+1,ta+1),…,(hb,tb)]Wherein t isb-taT is approximately distributed; a and b represent the index of the first and last array in the data queue, respectively;
step 5.2: extracting the gray values in the array to form a gray array [ ha,ha+1,…,hb]；
Step 5.3: take the sampling time asCarrying out fast Fourier transform on the gray array, and extracting the frequency f corresponding to the maximum amplitude;
step 5.4: obtaining a rotating speed value N according to the frequency f and the number X of the blades,
6. the method as claimed in claim 4, wherein the step of calculating the physical width of the tip clearance by the clearance measuring module in step 6 comprises:
step 6.1: carrying out noise reduction processing on the single-frame gray level image to obtain an image with high signal-to-noise ratio;
step 6.2: performing edge extraction on the image to obtain an edge image;
step 6.3: carrying out Hough transformation on the edge image, and continuously increasing the threshold value of the Hough transformation until the Hough transformation only returns two parallel or approximately parallel straight lines;
step 6.4: calculating the pixel value of the gap according to the linear information returned by Hough transformation;
the Hough transform returns information of a straight line: [ [ d ]l1,θl1],[dl2,θl2]]，
d is the intercept, the unit is the pixel value, theta is the angle; the index l1 is a first straight line, the index l2 is a second straight line,
the pixel value is then:
wherein: Δ θ ═ θl1-θl2；
Step 6.5: and finding the physical width of the gap corresponding to the pixel value of the gap according to the calibration information to obtain the physical width of the gap.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810255783.6A CN108645602B (en) | 2018-03-27 | 2018-03-27 | System and method for comprehensively measuring blade tip clearance and blade rotating speed of rotary machine and image processing program |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810255783.6A CN108645602B (en) | 2018-03-27 | 2018-03-27 | System and method for comprehensively measuring blade tip clearance and blade rotating speed of rotary machine and image processing program |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108645602A CN108645602A (en) | 2018-10-12 |
| CN108645602B true CN108645602B (en) | 2019-12-20 |
Family
ID=63744682
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810255783.6A Expired - Fee Related CN108645602B (en) | 2018-03-27 | 2018-03-27 | System and method for comprehensively measuring blade tip clearance and blade rotating speed of rotary machine and image processing program |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108645602B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110360920B (en) * | 2019-07-18 | 2021-01-29 | 天津大学 | Engine blade tip gap detection method based on FFT |
| CN113630554B (en) * | 2021-08-12 | 2022-06-28 | 北京航空航天大学 | Image acquisition device, method and system based on blade rotation angle |
| CN113819083B (en) * | 2021-09-30 | 2024-07-16 | 东风马勒热系统有限公司 | System for monitoring clearance value between silicone oil fan and air protection ring |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1888912A (en) * | 2006-07-20 | 2007-01-03 | 上海交通大学 | Rotating speed measuring divice based on computer vision |
| CN102661715A (en) * | 2012-06-08 | 2012-09-12 | 苏州富鑫林光电科技有限公司 | CCD (charge coupled device) type clearance measurement system and method |
| CN102967270A (en) * | 2012-11-14 | 2013-03-13 | 西南科技大学 | Method and system for measuring engine tip clearance |
| CN202903144U (en) * | 2012-11-14 | 2013-04-24 | 西南科技大学 | Blade tip clearance image measurement actuating mechanism |
| WO2015050657A1 (en) * | 2013-10-02 | 2015-04-09 | Siemens Energy, Inc. | Turbine blade-mounted sensor fixture for tip gap measurement |
| CN104704532A (en) * | 2012-09-14 | 2015-06-10 | 西门子公司 | A Hough transform approach to gap measurement in blade inspection |
| CN105223204A (en) * | 2015-11-02 | 2016-01-06 | 博格华纳汽车零部件（江苏）有限公司 | Supercharger impeller curved surface end face cosmetic injury checkout equipment and detection method |
| CN105627939A (en) * | 2015-12-17 | 2016-06-01 | 广东正业科技股份有限公司 | Device, method and system for detecting micro gap based on industrial equipment |
| CN106908246A (en) * | 2015-12-09 | 2017-06-30 | 通用电气公司 | System and method for performing the visual inspection of gas-turbine unit |
| CN107764198A (en) * | 2017-11-02 | 2018-03-06 | 天津大学 | Engine rotor and stator blade axial gap light projection measuring device and method |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9677868B2 (en) * | 2013-10-09 | 2017-06-13 | Hamilton Sundstrand Corporation | Tip clearance measurement system |
-
2018
- 2018-03-27 CN CN201810255783.6A patent/CN108645602B/en not_active Expired - Fee Related
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1888912A (en) * | 2006-07-20 | 2007-01-03 | 上海交通大学 | Rotating speed measuring divice based on computer vision |
| CN102661715A (en) * | 2012-06-08 | 2012-09-12 | 苏州富鑫林光电科技有限公司 | CCD (charge coupled device) type clearance measurement system and method |
| CN104704532A (en) * | 2012-09-14 | 2015-06-10 | 西门子公司 | A Hough transform approach to gap measurement in blade inspection |
| CN102967270A (en) * | 2012-11-14 | 2013-03-13 | 西南科技大学 | Method and system for measuring engine tip clearance |
| CN202903144U (en) * | 2012-11-14 | 2013-04-24 | 西南科技大学 | Blade tip clearance image measurement actuating mechanism |
| WO2015050657A1 (en) * | 2013-10-02 | 2015-04-09 | Siemens Energy, Inc. | Turbine blade-mounted sensor fixture for tip gap measurement |
| CN105223204A (en) * | 2015-11-02 | 2016-01-06 | 博格华纳汽车零部件（江苏）有限公司 | Supercharger impeller curved surface end face cosmetic injury checkout equipment and detection method |
| CN106908246A (en) * | 2015-12-09 | 2017-06-30 | 通用电气公司 | System and method for performing the visual inspection of gas-turbine unit |
| CN105627939A (en) * | 2015-12-17 | 2016-06-01 | 广东正业科技股份有限公司 | Device, method and system for detecting micro gap based on industrial equipment |
| CN107764198A (en) * | 2017-11-02 | 2018-03-06 | 天津大学 | Engine rotor and stator blade axial gap light projection measuring device and method |
Non-Patent Citations (3)
| Title |
|---|
| 发动机叶尖间隙影像测量系统的设计;范小虎 等;《应用光学》;20120731;第33卷(第4期);第743-744页第1节 * |
| 航空发动机叶尖间隙光学影像测量系统;范小虎 等;《西南科技大学学报》;20111231;第26卷(第4期);第57-58页第1节 * |
| 航空发动机叶尖间隙影像测量技术研究;郑臣 等;《西南科技大学学报》;20140930;第29卷(第3期);第90-91页第1节 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108645602A (en) | 2018-10-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| TWI788290B (en) | Estimation of yaw misalignment for a wind turbine | |
| CN108645602B (en) | System and method for comprehensively measuring blade tip clearance and blade rotating speed of rotary machine and image processing program | |
| DK2103915T3 (en) | Device and method for determining a resonant frequency of a wind turbine tower | |
| CN107101827B (en) | A kind of low-speed heavy-loaded gear crack fault online test method | |
| CN112381860B (en) | Unmarked computer vision method for measuring dynamic frequency of rotating blade | |
| CN102722706A (en) | Particle filter-based infrared small dim target detecting and tracking method and device | |
| CN111174958B (en) | Rotor blade surface universe dynamic pressure measuring device and method based on phase locking method | |
| CN101718582A (en) | Tone testing method of wind power generator set | |
| CN109558041B (en) | GPU acceleration-based blade tip clearance signal acquisition, processing and transmission method | |
| CN117609692B (en) | Method and device for diagnosing parallel level faults of gear boxes of wind generating set | |
| WO2020182806A1 (en) | Relative rotor blade misalignment | |
| CN114862809A (en) | Vibration monitoring method and device based on mobile terminal and image processing | |
| CN106338307B (en) | Wind turbines condition monitoring system and method with yaw status monitoring function | |
| EP2896016A1 (en) | A hough transform approach to gap measurement in blade inspection | |
| CN108333383B (en) | Rotational speed measurement system based on smart mobile phone and image processing | |
| CN113029553A (en) | Method, system and device for extracting rotating speed information of gearbox shaft and storage medium | |
| CN113504310B (en) | Blade natural frequency identification method based on single blade end timing sensor | |
| EP3882599B1 (en) | Detection of transient events | |
| CN109085374B (en) | Kinect-based multi-point speed measuring device for low-rotating-speed system and speed measuring method thereof | |
| CN115076028A (en) | Wind turbine generator set wind pairing method and system, wind turbine generator set and storage medium | |
| CN114810508A (en) | Image processing-based method and system for measuring rotating speed of fan blade of wind driven generator | |
| CN112879216B (en) | Wind speed correction method and device for wind power plant | |
| CN109871661B (en) | Method for recognizing and complementing loss of timing signals of leaf end | |
| US20130088587A1 (en) | Hough transform approach to gap measurement in blade inspection | |
| CN112504137B (en) | Multi-target digital image detection method based on cloud computing |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20191220 |
|
| CF01 | Termination of patent right due to non-payment of annual fee |