A method for calibrating and detecting the accuracy of optical fiber roof separation sensor

Abstract

A method for calibrating and detecting the accuracy of an optical fiber roof separation sensor, wherein the optical fiber roof separation sensor comprises a rectangular sensor body and a fixed tube vertically arranged in the middle of the sensor body, wherein a steel wire rope for measuring displacement distance is arranged in the fixed tube, and a calibration process is included, wherein the steel wire rope of the optical fiber roof separation sensor is pulled to several standard lengths, and the wavelength data of the internal grating transmitted back by the roof separation sensor is measured and recorded to form a data group, and the fitting coefficient and strain value of the data group are calculated to see whether they are within the qualified standard, so as to judge whether the roof separation sensor is of qualified quality.

Description

Technical Field

[0001] The invention relates to the field of mining and tunnel engineering, and in particular to a method for calibrating and detecting the accuracy of an optical fiber roof separation sensor. Background Art

[0002] The sinking and separation of the tunnel are invisible to the naked eye. If the sinking and separation of the tunnel will cause accidents, for safety reasons, a roof separation sensor must be installed in the coal mine tunnel. An anchor claw is set at the end of the roof separation sensor, anchored in a hole deep into the coal seam. When the coal seam at the anchor position is separated, the roof moves downward, and the internal transmission mechanism of the sensor is driven by the wire rope, which drives the pointer of the upper instrument of the roof separation sensor to rotate and display the value.

[0003] The inventor mentioned in another patent CN202010537543.2 an improved optical fiber roof abscission sensor for mines, in which an optical fiber grating is arranged on the internal transmission mechanism of the sensor. The internal transmission mechanism of the sensor can cause the wavelength of the grating inside the sensor to change. The sensor is connected to a fiber optic roof dynamic monitoring host outside the mine and can transmit the detected roof abscission situation to the outside of the mine through optical fiber for monitoring and recording.

[0004] Generally, sensors of various types and functions need to be calibrated before leaving the factory to detect whether there are any problems with the quality of the sensors and whether the accuracy of the sensors meets the factory standards. Currently, there is no calibration equipment on the market that can batch calibrate fiber optic top plate abscission sensors. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method for calibrating and detecting the accuracy of an optical fiber roof abscission sensor. A calibrator is used, which can calibrate the optical fiber roof abscission sensors in batches. The sensor body is fixed by a bracket pressure plate, and then the steel wire rope of the optical fiber roof abscission sensor is pulled by a lifting unit. The grating wavelength inside the optical fiber roof abscission sensor changes, which is recorded and calculated by the central control unit inside the calibrator.

[0006] The technical solution of the present invention is as follows:

[0007] A method for calibrating and detecting the accuracy of an optical fiber roof abscission sensor, wherein the optical fiber roof abscission sensor comprises a rectangular sensor body and a fixed tube vertically arranged in the middle of the sensor body, wherein a steel wire rope for measuring displacement distance is arranged in the fixed tube, and the method comprises a calibration process using a calibrator, wherein in the calibration process, the steel wire rope of the optical fiber roof abscission sensor is pulled to several standard lengths, the wavelength data of the internal grating transmitted back by the optical fiber roof abscission sensor is measured and recorded to form a data group, and the fitting coefficient and strain value of the data group are calculated to see whether they are within the qualified standard, so as to judge whether the optical fiber roof abscission sensor is of qualified quality.

[0008] The optical fiber top plate separation sensor accuracy calibration detection method as described above specifically needs to include a fixing process, a calibration process, and a calculation process.

[0009] As described above, a method for calibrating and detecting the accuracy of an optical fiber roof separation sensor is described, wherein the calibrator includes a fixed seat, a support frame, a lifting unit and a central control unit. The sensor body of the optical fiber roof separation sensor is fixed on the support frame, and the lifting unit is connected to a steel wire rope for pulling operation.

[0010] According to the above-mentioned method for calibrating the accuracy of the optical fiber top plate abscission sensor, the support frame includes a rectangular door-shaped frame, the lower end of which is vertically arranged on a fixed seat, a bracket seat is arranged between the support frames, and a plurality of bracket pressure plates are arranged on both sides of the bracket seat. The bracket pressure plate includes an L-shape, one end of which is arranged on the bracket seat, and the other end is in contact with the sensor body of the optical fiber top plate abscission sensor, and is used to fix the sensor body. Preferably, a pair of adjacent bracket pressure plates on the same side fix one sensor body.

[0011] As described above, in a method for calibrating and detecting the accuracy of an optical fiber top plate separation sensor, the support pressure plate includes a longitudinal beam, a transverse beam and an oblique beam, the longitudinal beam is vertically fixed on one side of a support seat, the transverse beam is rotatably connected to the longitudinal beam, the oblique beam is rotatably connected to the longitudinal beam, and is slidably connected to the transverse beam.

[0012] In the method for calibrating and detecting the accuracy of an optical fiber top plate separation sensor as described above, a limit buckle is provided on the cross beam, the limit buckle is provided in the cross beam, and the limit buckle is provided with a downwardly disposed inclined beam groove capable of buckling and limiting the inclined beam.

[0013] In the method for calibrating and detecting the accuracy of an optical fiber top plate separation sensor as described above, a screw rod is provided on each side of the support frame, the lifting unit is provided between the two screw rods, the screw rods are jointly driven to rotate by a cross bar, the cross bar is driven to rotate by a stepper motor, and the stepper motor is connected to the central control unit of the calibrator and controlled by the central control unit.

[0014] According to the above-mentioned method for calibrating the accuracy of the optical fiber top plate separation sensor, the fitting coefficient is R 2 The fitting coefficient R is the ratio of the regression sum of squares of the measured data set to the total sum of squares. 2 The distribution interval is (0,1), and the fitting coefficient R 2 Not less than 0.998 is qualified.

[0015] In the above-mentioned method for calibrating the accuracy of the optical fiber top plate separation sensor, the strain value is the difference between the maximum value and the minimum value of the internal grating wavelength in the measured data group, and the strain value is qualified if it is greater than or equal to 1.2 and less than or equal to 1.8.

[0016] The method for calibrating and detecting the accuracy of an optical fiber top plate separation sensor as described above comprises the following steps:

[0017] 1) Flip the crossbeam of the bracket plate 90 degrees relative to the longitudinal beam, and use a limit buckle to buckle the diagonal beam;

[0018] 2) placing the sensor body of the optical fiber top plate abscission sensor under the corresponding support plate;

[0019] 3) Fixing the steel wire rope of the optical fiber top plate separation sensor on the lifting unit;

[0020] 4) Connecting the output connector on the optical fiber top plate abscission sensor to the central control unit of the calibration instrument;

[0021] 5) starting the calibration instrument;

[0022] 6) The motor drives the crossbar to rotate, the crossbar drives the screw rod to rotate, the lifting unit is lifted, and the lifting unit pulls the steel wire rope of the optical fiber top plate separation sensor upward;

[0023] 7) The steel wire rope of the optical fiber top plate separation sensor is pulled upward, and stops several times, each stop lasting at least 30 minutes, and the data sent back by the optical fiber top plate separation sensor is recorded;

[0024] 8) Calculate the fitting coefficient and strain value of the data and compare them with the standard value to determine whether the quality of the optical fiber top plate abscission sensor under test is qualified.

[0025] The beneficial effects achieved by the present invention compared with the prior art are:

[0026] The present invention provides a method for calibrating and detecting the accuracy of an optical fiber roof separation sensor, including a calibration process using a calibrator. In order to make the calibration efficiency of the calibrator higher and the calibration more accurate, a number of paired bracket pressure plates are used to fix the sensor bodies of several optical fiber roof separation sensors, and the calibration efficiency is relatively high. The calibrator controls the stepper motor driven lifting unit to rise by a central control unit, pulls the steel wire rope of the optical fiber roof separation sensor, and the data measured by the optical fiber grating in the optical fiber roof separation sensor is recorded and calculated by the optical fiber transmitting to the central control unit of the calibrator. The force application standard is stable and the calibration is accurate during the whole process. The calibrator standardizes the entire calibration process, avoids various uncertainties in manual calibration, and ensures the quality of the products shipped out of the factory. The calibrator can calibrate multiple optical fiber roof separation sensors at the same time, greatly improving the calibration efficiency, reducing the use of labor, and reducing labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] By reading the detailed description of the preferred embodiment below, the scheme and advantages of the present application will become clear to those skilled in the art. The accompanying drawings are only for the purpose of illustrating the preferred embodiment and are not to be considered as limiting the present invention.

[0028] In the attached picture:

[0029] Figure 1 A flow chart of a method for calibrating and detecting the accuracy of an optical fiber top plate separation sensor provided by an embodiment of the present invention;

[0030] Figure 2 It is a front view of the calibration instrument used in the calibration process of the present invention;

[0031] Figure 3 A side view of a calibration instrument used in the calibration process of the present invention;

[0032] Figure 4 It is a schematic diagram of the support plate structure of the calibration instrument used in the calibration process of the present invention;

[0033] Figure 5 It is a schematic diagram of the limit buckle structure of the calibration instrument used in the calibration process of the present invention;

[0034] Figure 6 It is a schematic diagram of the structure of the lifting unit of the calibration instrument used in the calibration process of the present invention;

[0035] The components represented by the reference numerals in the figure are:

[0036] 1. Fixed seat, 2. Support frame, 21. Vertical frame, 22. Soft ruler, 23. Bracket seat, 24. Bracket pressure plate, 241. Longitudinal beam, 242. Cross beam, 243. Oblique beam, 244. Limit buckle, 25. Screw rod, 26. Cross bar, 27. Stepper motor, 3. Lifting unit, 31. Lifting plate, 32. Weighing sensor, 4. Fiber optic top plate separation sensor, 41. Sensor body, 42. Fixed tube, 43. Wire rope. DETAILED DESCRIPTION

[0037] The exemplary embodiments of the present disclosure will be described in more detail below in conjunction with the accompanying drawings. It should be noted that these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. The present disclosure can be implemented in various forms and should not be limited by the embodiments described herein.

[0038] The directions "front and back", "left and right", etc. mentioned in the present invention are only used to express relative positional relationships and are not restricted by any specific direction reference in practical applications.

[0039] Example

[0040] See also Figure 1-Figure 3 A method for calibrating and detecting the accuracy of an optical fiber roof abscission sensor, wherein the optical fiber roof abscission sensor 4 comprises a rectangular sensor body 41 and a fixed tube 42 vertically arranged in the middle of the sensor body 41, wherein a steel wire rope 43 for measuring the displacement distance is arranged in the fixed tube 42, and wherein the method comprises a calibration process, wherein the steel wire rope of the optical fiber roof abscission sensor 4 is pulled to several standard lengths, the wavelength data of the internal grating transmitted back by the optical fiber roof abscission sensor 4 is measured and recorded to form a data group, and the fitting coefficient and strain value of the data group are calculated to see whether they are within the qualified standard, so as to judge whether the optical fiber roof abscission sensor 4 is of qualified quality.

[0041] Furthermore, the specific calibration needs to include a fixing process, a calibration process, and a calculation process.

[0042] Furthermore, the calibration instrument of the optical fiber top plate separation sensor 4 includes a fixed seat 1, a support frame 2, a lifting unit 3 and a central control unit. The sensor body 41 of the optical fiber top plate separation sensor 4 is fixed on the support frame 2, and the lifting unit 3 is connected to the wire rope 43 for pulling operation.

[0043] Furthermore, the support frame 2 includes two vertical frames 21, which are vertically arranged on both sides of the fixed base 1. The middle of the vertical frames 21 is hollow, and a soft ruler 22 is arranged on one of the vertical frames 21. Through the soft ruler 22, the staff can directly read the stretched length and directly compare it with the data displayed by the optical fiber top plate abscission sensor 4, so as to roughly judge whether the optical fiber top plate abscission sensor 4 has quality problems.

[0044] Furthermore, the support frame 2 includes a rectangular door-shaped frame, the lower end of which is vertically arranged on the fixed seat 1, and a bracket seat 23 is arranged between the support frames 2. Several bracket pressure plates 24 are arranged on both sides of the bracket seat 23. The bracket pressure plate 24 includes an L-shape, one end of which is arranged on the bracket seat 23, and the other end is in contact with the sensor body 41 of the optical fiber top plate abscission sensor 4, and is used to fix the sensor body 41. Preferably, a pair of adjacent bracket pressure plates 24 on the same side fix one sensor body 41.

[0045] See also Figure 4 and Figure 5 The support plate 24 includes a longitudinal beam 241, a transverse beam 242 and an oblique beam 243. The longitudinal beam 241 is vertically fixed on one side of the support seat 23. The transverse beam 242 is rotatably connected to the longitudinal beam 241. The oblique beam 243 is rotatably connected to the longitudinal beam 241 and slidably connected to the transverse beam 242.

[0046] Furthermore, a limit buckle 244 is provided on the cross beam 242 , and the limit buckle 244 is arranged in the cross beam 242 . The limit buckle 244 is provided with a downwardly arranged inclined beam 243 groove capable of buckling and limiting the inclined beam 243 .

[0047] Preferably, in this embodiment, both sides of the cross beam 242 are provided with through sliding holes, the sliding holes are long strips, the inclined beams 243 are provided in pairs on both sides of the longitudinal beam 241 and the sliding holes, the upper ends of the two inclined beams 243 are rotatably connected to the longitudinal beam 241, and the lower ends are connected by bolts passing through the sliding holes. The maximum angle between the longitudinal beam 241 and the cross beam 242 is 90 degrees, and when the angle between the longitudinal beam 241 and the cross beam 242 is 90 degrees, the lower end of the inclined beam 243 slides to the innermost end of the sliding hole.

[0048] Preferably, the limit buckle 244 in this embodiment is arranged above the sliding hole in the beam 242, and the limit buckle 244 is provided with a rotating shaft passing through the left and right sides and is rotatably connected with the beam 242. The rotating shaft divides the limit buckle 244 into an inner limit clamp and an outer handle, and a spring is arranged below the handle, one end of the spring is connected to the bottom of the handle, and the other end is connected above the sliding hole.

[0049] Furthermore, the slots of the inclined beam 243 are arranged on both sides of the limiting clamp, and the openings of the slots of the inclined beam 243 are not less than the diameter of the bolts arranged between the two inclined beams 243. When the angle between the longitudinal beam 241 and the transverse beam 242 needs to be fixed at 90 degrees, the handle of the limiting buckle 244 is pressed downward, and the limiting clamp tilts upward. At this time, the lower end of the moving inclined beam 243 slides to the innermost end of the sliding hole, which is also directly below the slot of the inclined beam 243. At this time, the handle is released, and under the action of the spring, the bolts between the two inclined beams 243 enter the slots of the inclined beam 243, completing the position limitation of the longitudinal beam 241 and the transverse beam 242.

[0050] See also Figure 6 A screw rod 25 is respectively arranged in the middle of the vertical frames 21 on both sides of the support frame 2, and the lifting unit 3 is arranged between the two screw rods 25. The screw rods 25 are synchronously driven to rotate by a cross bar 26. The cross bar 26 is driven to rotate by a stepper motor 27. The stepper motor 27 is connected to the central control unit of the calibrator and controlled by the central control unit.

[0051] Furthermore, the lifting unit 3 includes a lifting plate 31 and a weighing sensor 32. Three weighing sensors 32 are symmetrically arranged on the front and rear sides of the lifting plate 31, with a total of six weighing sensors 32 on both sides. The head of the weighing sensor 32 is connected to the steel wire rope 43 of the top plate separation sensor.

[0052] Preferably, a screw nut 25 is provided between the lifting plate 31 and the screw 25 for connection. Furthermore, the threads on the two screws 25 have the same rotation direction, and the threads on the inner sides of the screw nuts have the same direction.

[0053] Preferably, the top of the weighing sensor 32 described in this embodiment is a horizontal ring, and a rope loop is provided at the end of the steel wire rope 43 of the optical fiber top plate abscission sensor 4. The rope loop passes through the ring at the top of the weighing sensor 32, and then a horizontal short rod passes through the rope loop to complete the fixation of the steel wire rope 43 and the weighing sensor 32. The length of the short rod is greater than the diameter of the top ring of the weighing sensor 32.

[0054] The measuring range of the optical fiber top plate separation sensor 4 calibrated in this embodiment is 500 mm.

[0055] like Figure 1 As shown, this embodiment develops a pipeline calibration method integrating "fixing-calibration-calculation" for the above steps. The specific process includes:

[0056] 1) placing the six optical fiber top plate separation sensors 4 respectively under the corresponding support pressure plates 24;

[0057] 2) Flip the crossbeam 242 of the bracket pressure plate 24 by 90 degrees relative to the longitudinal beam 241, press the handle of the limit buckle 244 downward, and the limit clamp will tilt upward. At this time, the lower end of the moving inclined beam 243 slides to the innermost end of the sliding hole, which is also directly below the groove of the inclined beam 243. At this time, release the handle. Under the action of the spring, the bolts between the two inclined beams 243 enter the groove of the inclined beam 243, completing the position locking of the longitudinal beam 241 and the crossbeam 242;

[0058] 3) Pass the rope loop of the steel wire rope 43 of the optical fiber top plate separation sensor 4 through the ring at the top of the weighing sensor 32, and then pass a short horizontal rod through the rope loop to complete the fixation of the steel wire rope 43 and the weighing sensor 32;

[0059] 4) Connecting the optical fiber connectors of all optical fiber top plate abscission sensors to the corresponding optical fiber interfaces;

[0060] 5) starting the calibration instrument;

[0061] 6) The stepper motor 27 is powered on and rotates to drive the cross bar 26 to rotate, and the cross bar 26 drives the two screw rods 25 to rotate, and the lifting unit 3 is lifted upward.

[0062] 7) When the lifting unit 3 is lifted to a height of 100 mm, the data transmitted back by the optical fiber top plate separation sensor 4 through the optical fiber is recorded once, and the recording is kept for 30 minutes to detect whether the data transmitted back by the optical fiber top plate separation sensor 4 through the optical fiber changes within 30 minutes;

[0063] 8) Repeat step 7 when the height is raised to 200 mm, repeat step 7 when the height is raised to 300 mm, repeat step 7 when the height is raised to 400 mm, repeat step 7 when the height is raised to 500 mm, and record the corresponding data;

[0064] 9) Calculate the fitting coefficients and strain values ​​for all recorded data.

[0065] Specific method for calculating fitting coefficients and strain values:

[0066] The data transmitted back by the optical fiber roof separation sensor 4 through the optical fiber, that is, the wavelength of the grating inside the sensor. The distance of the lifting platform 3 measured by the roof separation sensor 9 under the standard state is the independent variable x, and the wavelength of the grating inside the sensor is the dependent variable y, and a fitting straight line p(x) = a + bx is made. The fitting coefficient is set to R 2 .

[0067]

[0068] Regression sum of squares = total sum of squares / residual sum of squares

[0069] Total sum of squares = sum of squares of actual y values

[0070] Assume that the actual measured value is y i , the values ​​calculated by the fitting straight line p(x) = a + bx are Y i

[0071] Residual sum of squares:

[0072] Total sum of squares:

[0073]

[0074] R 2 Distribution interval (0,1), R 2 The smaller the value, the worse the fit. 2 The larger the coefficient, the better the fit. The fit coefficient calculated in this embodiment is not less than 0.998, which is considered qualified.

[0075] The difference between the wavelength of the internal grating of the sensor when the lifting platform 3 is lifted to a height of 500 mm and the wavelength of the internal grating of the sensor when the lifting platform 3 is lifted to a height of 0 mm is the strain value.

[0076] The strain value is qualified if it is greater than or equal to 1.2 and less than or equal to 1.8.

[0077] The top plate separation sensor 9 that satisfies the above fitting coefficient and strain value at the same time is qualified.

[0078] The measured data of this embodiment are shown in the following table (the unit of the measured data is nm):

[0079]

[0080] Combined with the above table, it can be seen that the fitting coefficient of sensor No. 4 is 0.9974, which is less than the standard 0.998, so it is unqualified. The other five optical fiber top plate abscission sensors meet the quality standards and can be shipped.

[0081] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or additions, subtractions or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for calibrating the accuracy of an optical fiber roof separation sensor, wherein the optical fiber roof separation sensor comprises a sensor body and a fixing tube vertically arranged in the sensor body, wherein a steel wire rope for measuring displacement distance is arranged in the fixing tube, characterized in that: The method comprises a calibration process using a calibrator, in which the wire rope of the optical fiber roof separation sensor is pulled to several standard lengths, the wavelength data of the internal grating transmitted back by the optical fiber roof separation sensor is measured and recorded to form a data group, and the fitting coefficient and strain value of the data group are calculated to determine whether they are within the qualified standard, so as to determine whether the roof separation sensor is of qualified quality; The calibration instrument comprises a fixing seat, a supporting frame, a lifting unit and a central control unit. The sensor body of the optical fiber top plate separation sensor is fixed on the supporting frame, and the lifting unit is connected to a steel wire rope for lifting operation; The support frame includes a rectangular door-shaped frame, the lower end of which is vertically arranged on a fixed seat, a support seat is arranged between the support frames, and a plurality of support pressing plates are arranged on both sides of the support seat, and the support pressing plate includes an L-shape, one end of which is arranged on the support seat, and the other end is in contact with the sensor body of the optical fiber top plate separation sensor, and is used to fix the sensor body; The support plate comprises a longitudinal beam, a transverse beam and an oblique beam, wherein the longitudinal beam is vertically fixed on one side of the support seat, the transverse beam is rotatably connected to the longitudinal beam, and the oblique beam is rotatably connected to the longitudinal beam and slidably connected to the transverse beam; A limit buckle is arranged on the cross beam, and the limit buckle is arranged in the cross beam. The limit buckle is provided with a downwardly arranged inclined beam groove which can buckle and limit the inclined beam.

2. The method for calibrating the accuracy of an optical fiber top plate separation sensor according to claim 1, characterized in that: The specific calibration needs to include fixing process, calibration process and calculation process.

3. The method for calibrating the accuracy of an optical fiber top plate separation sensor according to claim 1, characterized in that: A screw rod is arranged on each side of the support frame, and the lifting unit is arranged between the two screw rods. The screw rods are driven to rotate by a cross bar, and the cross bar is driven to rotate by a stepping motor.

4. The method for calibrating the accuracy of an optical fiber top plate separation sensor according to claim 1, characterized in that: The fitting coefficients are , which is equal to the ratio of the regression sum of squares of the measured data set to the total sum of squares, the fitting coefficient The distribution interval is (0,1), the fitting coefficient Not less than 0.998 is qualified.

5. The method for calibrating the accuracy of an optical fiber top plate separation sensor according to claim 1, characterized in that: The strain value is the difference between the maximum value and the minimum value of the internal grating wavelength in the measured data group. The strain value is qualified if it is greater than or equal to 1.2 and less than or equal to 1.

8.

6. The method for calibrating the accuracy of an optical fiber top plate separation sensor according to claim 3, characterized in that: The optical fiber top plate separation sensor accuracy calibration detection method comprises the following steps: Flip the crossbeam of the bracket pressure plate 90 degrees relative to the longitudinal beam, and use a limit buckle to buckle the diagonal beam; Placing the sensor body of the optical fiber top plate separation sensor under the corresponding support pressure plate; Fixing the steel wire rope of the optical fiber top plate separation sensor on the lifting unit; Connect the output connector on the optical fiber top plate abscission sensor to the central control unit of the calibrator; Starting the calibration instrument; The motor drives the crossbar to rotate, the crossbar drives the lead screw to rotate, the lifting unit is lifted, and the lifting unit pulls the steel wire rope of the optical fiber top plate separation sensor upwards; The steel wire rope of the optical fiber top plate separation sensor is pulled upward, and stops several times, each stop lasting at least 30 minutes, and the data sent back by the optical fiber top plate separation sensor is recorded; 8) Calculate the fitting coefficient and strain value of the data and compare them with the standard value to determine whether the optical fiber top plate abscission sensor under test is standard.

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