Full-automatic metering calibration system for tachometer

Abstract

The invention discloses a tachometer full-automatic metering calibration system comprising a rotating speed standard device which is provided with a plurality of rotating shafts with reflective stickers; the industrial camera is used for collecting the display reading of the tachometer; the distance measuring unit is used for detecting the distance between the detected tachometer and the rotating speed standard device; the Z-direction module is used for installing an industrial camera and a detected tachometer; the Y-direction module is used for driving the Z-direction module to move left and right; a plurality of limit switches are arranged and respectively correspond to the positions of the plurality of rotating shafts with the reflection stickers so as to control the position of the Z-direction module; the X-direction module is used for driving the distance measuring unit to move so as to control the distance between the detected tachometer and the rotating speed standard device; and the computer is used for setting the distance between the detected tachometer and the rotating speed standard device and a rotating speed calibration point so as to control the movement of the X-direction module and the Y-direction module, collecting the detection data of the detected tachometer, and calculating a rotating speed indication error by combining a rotating speed measurement value obtained by a picture obtained by the industrial camera.

Description

Technical Field

[0001] The invention belongs to the field of speed measuring instruments, in particular to a full-automatic measurement and calibration system for a speed meter. Background Art

[0002] The tachometer is mainly used to measure the rotation speed of various rotating objects. It is a commonly used speed measuring instrument. Its accuracy directly affects product quality and production progress. In the field of tachometer measurement and calibration, foreign institutions mostly focus on image processing methods, mainly based on image processing to extract the features of the pointer and dial, and then extract the pointer straight line and scale line according to the Hough transform, and then calculate the instrument reading by detecting the pointer inclination or the relative position of the pointer on the scale line. Alegria EC, Serra AC. Automatic calibration of analog and digital measuring instruments using computer vision [J]. IEEE Transactions on Instrumentation & Measurement, 2000. discloses a method of introducing Hough transform into pointer instrument recognition, which greatly broadens the scope of application of automatic recognition technology and is used as the most classic straight line detection algorithm.

[0003] Domestic institutions also focus on image processing methods. Yang Zhijuan, Yuan Zongheng, Qiao Yu, et al. Research on intelligent identification methods of pointer instruments based on image processing [J]. Computer Measurement and Control, 2015. A method for locating the instrument by using the circular area cumulative histogram method is proposed, and then the instrument reading is read. Tao Bingjie, Han Jiale, Li En. A practical method for identifying pointer instrument readings [J]. Optoelectronic Engineering, 2011. A method is proposed to improve the image quality of pointer instruments by using the median filtering method, and then the feature information in the image is extracted by combining the improved double threshold Hough transform, and finally the pointer instrument reading is read by combining the angle method.

[0004] The above-mentioned domestic and foreign institutions use image processing algorithms to identify tachometer readings, but none of them have achieved fully automatic measurement and calibration of the tachometer. They have only achieved automatic reading of the readings. When measuring different speed points, the speed still needs to be manually adjusted, which affects the improvement of measurement work efficiency. Summary of the invention

[0005] The purpose of the present invention is to provide a tachometer full-automatic measurement and calibration system to solve the current tachometer measurement and calibration problems.

[0006] The technical solution to achieve the purpose of the present invention is:

[0007] A tachometer fully automatic measurement and calibration system, comprising:

[0008] The speed standard device, as a speed standard source for testing the tachometer under test, is provided with a plurality of rotating shafts with reflective stickers;

[0009] Industrial camera, used to collect the display readings of the tachometer and transmit them to the computer;

[0010] Distance measuring unit, used to detect the distance between the tachometer under test and the speed standard device;

[0011] Z-axis module, used to install industrial cameras and tachometers to be inspected;

[0012] The Y-axis module is used to drive the Z-axis module to move left and right, so that the tachometer under inspection is aligned with the rotating shaft with the reflective sticker in the corresponding speed measurement range; multiple limit switches are provided, corresponding to the positions of multiple rotating shafts with reflective stickers, so as to control the position of the Z-axis module;

[0013] The X-axis module is used to drive the distance measuring unit to move and realize the control of the distance between the tachometer under inspection and the speed standard device;

[0014] The computer is used to set the distance between the tachometer under test and the speed standard device and the speed calibration point to control the movement of the X-axis module and the Y-axis module, and collect the test data of the tachometer under test, and calculate the speed indication error by combining the speed measurement value obtained by the picture obtained by the industrial camera.

[0015] Compared with the prior art, the present invention has the following significant advantages:

[0016] The present invention solves the technical problems of large human error, low metrological work efficiency and inability to perform batch metrological calibration in the process of fully automatic metrological calibration of tachometers, and realizes fully automatic metrological calibration of tachometers; adopts standard speed automatic control and adjustment technology, solves the problems of manual step-by-step adjustment of speed and unstable speed source output during tachometer calibration, and improves the automation of the calibration process; adopts a combination of data communication acquisition and image calculation to realize accurate calculation of speed calibration value; adopts automatic control program to realize automatic metrological calibration of tachometers. The calibration process is simple, and the high measurement accuracy greatly improves the efficiency of metrological calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the tachometer's fully automatic measurement and calibration device. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0019] Combination Figure 1The present embodiment is a tachometer automatic measurement and calibration system, which includes a speed standard source, a motion module, an image acquisition module, etc. The speed standard source adopts a speed standard device 10, the motion module adopts an X-axis module 14, a Y-axis module 12, and a Z-axis module 11, and the image acquisition module adopts an industrial camera 9 and a computer 1; the speed standard source, the motion module, and the image acquisition module are all arranged on an electrical cabinet 19.

[0020] Among them, the computer 1 is connected to the industrial camera 9 by using the industrial camera data cable 2; the computer 1 is connected to the tachometer 5 to be inspected by using the tachometer data communication line 3 and the data acquisition card; the rotating shaft A6 with a reflective sticker, the rotating shaft B7 with a reflective sticker, and the rotating shaft C8 with a reflective sticker are installed on the speed standard device 10; the industrial camera 9 and the tachometer fixing tool 4 are installed on the Z-axis module 11; the photoelectric switch A15, the photoelectric switch B16, the photoelectric switch C17, and the laser displacement sensor 18 are installed on the Y-axis module 12; the X-axis module 14, the Y-axis module 12, and the Z-axis module 11 are connected by the fixture tool 13. The industrial camera 9 is used to collect the display readings of the tachometer 5 under test and transmit them to the computer 1; the computer 1 collects the detection data of the tachometer 5 under test, which can set calibration points and is connected to the controller. The controller controls the movement of the X-axis module 14 and the Y-axis module 12, so that the tachometer 5 under test moves to the photoelectric switch at the corresponding position, so that the signal emitted by the tachometer 5 under test hits the corresponding rotating shaft surface with the reflective sticker, and the corresponding speed calibration point is detected.

[0021] The speed range of rotating axis A with reflective sticker is 1~4000r / min, the speed range of rotating axis B with reflective sticker is 4000~10000r / min, and the speed range of rotating axis C with reflective sticker is 10000~100000r / min; the position of photoelectric switch A15 corresponds to rotating axis A6 with reflective sticker, the position of photoelectric switch B16 corresponds to rotating axis B7 with reflective sticker, and the position of photoelectric switch C17 corresponds to rotating axis C8 with reflective sticker. For example, when the speed is 200r / min, 200r / min is input into the computer, and the Y-axis module 12 drives the Z-axis module 11 to move left and right. When the Z-axis module 11 moves to the position of photoelectric switch A15, it stops. At this time, the tachometer 5 under inspection is aligned to the rotating axis A with reflective sticker.

[0022] During metrological calibration, first turn on the signal switch of the tachometer 5 to be inspected, fix the tachometer 5 with the tachometer fixing fixture 4, set the speed measurement point (calibration point) through the computer, and the system automatically controls the Z-axis module 11 to move left and right along the Y-axis module 12 to the corresponding photoelectric switch position (a certain position of photoelectric switches A, B, and C), stop and hold. At this time, the signal sent by the tachometer 5 to the corresponding rotating shaft surface with a reflective sticker; finally, the system controls the X-axis module 14 to move forward and backward. When the value of the laser displacement sensor 18 shows the set value d (to ensure that the tachometer 5 to be inspected maintains a certain distance from the speed standard device 10, which is set by the computer), the X-axis module 14 stops and holds. According to the metrological calibration requirements of the tachometer to be inspected, the calibration points m1, m2...m in the measurement range of the tachometer need to be n For example, when measuring the speed calibration point m1, firstly, the image obtained by the industrial camera (for example, the speed digital display is 200r / min) is transmitted to the computer for image recognition and processing to obtain the speed measurement value x1 (200r / min). At the same time, the measurement data y1 in the tachometer is collected to the computer through the data communication line. The maximum allowable error of the measurement results of the two speed measurement methods is k. If |x1-y1|≤k is satisfied, then the speed measurement value at this time is Speed ​​indication error d1 = z1-m1; if |x1-y1|>k, then discard the measurement result and re-measure. Use the same method to complete the remaining speed calibration point indication errors d2, d3...d n This method combines data communication acquisition with image calculation and has the characteristics of high measurement accuracy and simple algorithm to meet the requirements of tachometer measurement and calibration.

Claims

1. A tachometer fully automatic measurement and calibration system, characterized in that: include: The speed standard device, as a speed standard source for testing the tachometer under test, is provided with a plurality of rotating shafts with reflective stickers; Industrial camera, used to collect the display readings of the tachometer and transmit them to the computer; Distance measuring unit, used to detect the distance between the tachometer under test and the speed standard device; Z-axis module, used to install industrial cameras and tachometers to be inspected; The Y-axis module is used to drive the Z-axis module to move left and right, so that the tachometer under inspection is aligned with the rotating shaft with the reflective sticker in the corresponding speed measurement range; multiple limit switches are provided, corresponding to the positions of multiple rotating shafts with reflective stickers, so as to control the position of the Z-axis module; The X-axis module is used to drive the distance measuring unit to move and realize the control of the distance between the tachometer under inspection and the speed standard device; The computer is used to set the distance between the tachometer under test and the speed standard device and the speed calibration point to control the movement of the X-axis module and the Y-axis module, and collect the test data of the tachometer under test, and calculate the speed indication error by combining the speed measurement value obtained by the picture obtained by the industrial camera.

2. The tachometer automatic measurement and calibration system according to claim 1 is characterized in that: The process of the computer calculating the speed indication error is as follows: Compare the speed measurement value x1 obtained from the image captured by the industrial camera with the detection data y1 collected by the computer: If |x1-y1|≤k is satisfied, then the speed measurement value is The speed indication error d1 = z1 - m1; if |x1 - y1| > k, the measurement result is discarded and re-measured; where k is the maximum allowable error of the measurement result.

3. The tachometer automatic measurement and calibration system according to claim 1 is characterized in that: The distance measuring unit adopts a laser displacement sensor and is arranged on the Y-axis module.

4. The tachometer automatic measurement and calibration system according to claim 1 is characterized in that: The limit switch adopts a photoelectric switch, and three groups are provided, corresponding to three groups of rotating shafts with reflective stickers in different speed ranges.

5. The tachometer automatic measurement and calibration system according to claim 1 is characterized in that: The X-axis module, the Y-axis module and the Z-axis module are connected by a fixture.

6. The tachometer automatic measurement and calibration system according to claim 1 is characterized in that: Installed on the electrical cabinet.

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