Device and method for distributed detection of straightness of working face of scraper conveyor based on optical fiber sensing

This application is a 371 of international application of PCT application serial no. PCT/CN2020/085886, filed on Apr. 21, 2020, which claims the priority benefit of China application no. 202010022172.4, filed on Jan. 9, 2020. The entirety of each of the above mentioned patent applications is hereby incorporated by reference herein and made a part of this specification.

The present invention belongs to the field of monitoring of a working state of fully-mechanized mining equipment in a mine; and relates to distributed detection of straightness of a working face of a scraper conveyor, and in particular, to a device and method for distributed detection of straightness of a working face of a scraper conveyor based on optical fiber sensing.

A scraper conveyor is one of the key equipment on the fully-mechanized coal mining face, and its performance directly affects mine safety and a production level. In addition to transporting coal, the scraper conveyor can also be used as a moving track for a shearer and a pivot point for a hydraulic support. If the straightness of the scraper conveyor in a running direction is poor, the wear and tear of a scraper chain is aggravated, and further the safety of coal production is affected. Moreover, because the shearer reciprocates with the scraper conveyor as the running track, relatively poor straightness may cause an error in cutting displacement. Therefore, it is rather important to ensure that the scraper conveyor runs in a straight line.

The existing straightness detection means are mainly as follows: Gyroscope-based inertial navigation technology is used to draw a travelling track of the shearer to obtain the straightness of a working face of the scraper conveyor. However, the gyroscope apparatus is expensive, bringing a high cost. Laser calibration is conducted on the scraper conveyor and a high-definition camera is used to capture images to obtain the straightness of the working face of the scraper conveyor. However, this method has relatively low measurement precision and the captured images are unsharp in a high-dust condition. A laser distance meter is installed on a hydraulic support to detect the position of the hydraulic support relative to the scraper conveyor, thus indirectly measuring the straightness of the working face of the scraper conveyor. However, it is difficult to implement this method because the support may pitch during movement.

One objective of the present invention is to provide a device for distributed detection of straightness of a working face of a scraper conveyor based on optical fiber sensing, which has a simple structure, high resistance to electromagnetic interference, and high precision.

Another objective of the present invention is to provide a detection method of the above-described device for distributed detection of straightness of a working face of a scraper conveyor based on optical fiber sensing, which can realize direct measurement of the straightness of the working face of the scraper conveyor.

To achieve the foregoing objectives, the present invention adopts the following technical solutions: A device for distributed detection of straightness of a working face of a scraper conveyor based on optical fiber sensing is provided, including: a broadband light source, a first optical fiber circulator array, a second optical fiber circulator array, a collimator array, a reflecting film array, a third optical fiber circulator array, and an optical path analyzer, where the first optical fiber circulator array includes a plurality of first optical fiber circulators A which are successively connected in series via a fiber grating, and single-mode optical fibers (SMFs) connected at second ports of the plurality of first optical fiber circulators A are etched with Bragg gratings with central wavelengths of λ 1 , λ 2 . . . λ n respectively; the broadband light source is connected in series to the first optical fiber circulator array via an SMF; the second optical fiber circulator array includes a plurality of second optical fiber circulators B, and the collimator array includes a plurality of collimators arranged at equal intervals; the reflecting film array includes a plurality of reflecting films adhered to the working face in a running direction of the scraper conveyor, and an array interval between the reflecting films is equal to that between the collimators; and the third optical fiber circulator array includes a plurality of third optical fiber circulators C successively connected in series via an SMF, and the optical path analyzer is connected in series to the third optical fiber circulator array via an SMF.

The first optical fiber circulator array, the second optical fiber circulator array, the collimator array, and the third optical fiber circulator array are arranged in a direction parallel to an arrangement direction of the reflecting film array; and equal numbers of the first optical fiber circulators A, the second optical fiber circulators B, the collimators, the reflecting films, and the third optical fiber circulators C are arranged. Third ports of the first optical fiber circulators A are connected to first ports of the second optical fiber circulators B respectively, second ports of the second optical fiber circulators B are connected to the collimators respectively, and third ports of the second optical fiber circulators B are connected to first ports of the third optical fiber circulators C respectively.

Preferably, the arrangement numbers of the first optical fiber circulators A, the second optical fiber circulators B, the collimators, the reflecting films, and the third optical fiber circulators C are all not less than three.

Preferably, the reflecting film is a thin sheet coated with a metal film on the surface and having a thickness less than 1 mm.

The present invention further provides a detection method of the above-described device for distributed detection of straightness of a working face of a scraper conveyor based on optical fiber sensing.

A broadband spectrum output by a broadband light source enters a first optical fiber circulator A 1 ranked first from a first port of the first optical fiber circulator A 1 , and is then output from a second port of the first optical fiber circulator A 1 . The light output from the second port of the first optical fiber circulator A 1 reaches a first optical grating and light with a wavelength of λ 1 is returned. The light with the wavelength of λ 1 enters a second optical fiber circulator B 1 ranked first through a first port of the second optical fiber circulator B 1 , and reaches a first reflecting film through a first collimator after being output from a second port of the second optical fiber circulator B 1 . The light with the wavelength of λ 1 returns back to the second optical fiber circulator B 1 through the first collimator from the second port of the second optical fiber circulator B 1 under the effect of the first reflecting film, and is output from a third port of the second optical fiber circulator B 1 . The light output from the third port of the second optical fiber circulator B 1 enters a third optical fiber circulator C 1 ranked first through a first port of the third optical fiber circulator C 1 , and enters an optical path analyzer through an SMF after being output from a second port of the third optical fiber circulator C 1 .

Light of the remaining wavelength that is not returned after the light is output from the second port of the first optical fiber circulator A 1 and reaches the first optical grating is continuously transmitted forward, enters from a first port of a first optical fiber circulator A 2 ranked second, and is output from a second port of the first optical fiber circulator A 2 . The light output from the second port of the first optical fiber circulator A 2 reaches a second optical grating and light with a wavelength of λ 2 is returned. The light with the wavelength of λ 2 enters a second optical fiber circulator B 2 ranked second through a first port of the second optical fiber circulator B 2 , and reaches a second reflecting film through a second collimator after being output from a second port of the second optical fiber circulator B 2 . The light with the wavelength of λ 2 returns back to the second optical fiber circulator B 2 through the second collimator from the second port of the second optical fiber circulator B 2 under the effect of the second reflecting film, and is output from a third port of the second optical fiber circulator B 2 . The light output from the third port of the second optical fiber circulator B 2 enters a third optical fiber circulator C 2 ranked second through a first port of the third optical fiber circulator C 2 , and enters the optical path analyzer through an SMF after being output from a second port of the third optical fiber circulator C 2 .

Light of the remaining wavelength that is not returned after the light is output from the second port of the first optical fiber circulator A 2 and reaches the second optical grating is continuously transmitted forward, and the rest is deduced by analogy; therefore, light with the wavelengths of λ 1 , λ 2 , λ 3 , . . . , λ n all enters the optical path analyzer through the SMF. The optical path analyzer calculates transmission distances of the different wavelengths of light, to obtain positions of different reflecting films. Because the position points of the reflecting films are corresponding to positions on the scraper conveyor, the straightness of a working face of the scraper conveyor in a running direction is obtained according to connecting lines between the position points.

Compared to the prior art, the present invention realizes positioning of points on a working face according to information of path lengths at which different wavelengths of light are reflected back after reaching the working face. Based on this ingenious concept, after obtaining positions of the different points on the working face in a running direction of a scraper conveyor, the present invention realizes detection of the straightness of the working face according to these position points. The present invention has such advantages as high resistance to electromagnetic interference, a simple structure, and high measurement precision.

FIG. 1 is a schematic principle diagram of an optical path in an embodiment of the present invention.

Meanings of numerals: 1 . Broadband light source, 2 . First optical fiber circulator array, 3 . Fiber grating, 4 . Second optical fiber circulator array, 5 . Collimator array, 6 . Reflecting film array, 7 . Third optical fiber circulator array, 8 . Optical path analyzer, 9 . Working face of a scraper conveyor.

The present invention is further described in detail below with reference to the accompanying drawing and a specific embodiment.

As shown in FIG. 1 , a device for distributed detection of straightness of a working face of a scraper conveyor based on optical fiber sensing includes a broadband light source 1 , a first optical fiber circulator array 2 , a second optical fiber circulator array 4 , a collimator array 5 , a reflecting film array 6 , a third optical fiber circulator array 7 , and an optical path analyzer 9 . The first optical fiber circulator array 2 includes first optical fiber circulators A 1 , A 2 , and A 3 which are successively connected in series via a fiber grating 3 , and the fiber grating 3 is etched with a grating array. An SMF between the first optical fiber circulators A 1 and A 2 is etched with a Bragg grating with a central wavelength of λ 1 , an SMF between the first optical fiber circulators A 2 and A 3 is etched with a Bragg grating with a central wavelength of λ 2 , and an SMF connected at a second port of the first optical fiber circulator A 3 is etched with a Bragg grating with a central wavelength of λ 3 . The broadband light source 1 is connected in series to the first optical fiber circulator array 2 via an SMF.

The second optical fiber circulator array 4 includes second optical fiber circulators B 1 , B 2 , and B 3 ; and the collimator array 5 includes collimators 51 , 52 , and 53 arranged at equal intervals. The reflecting film array 6 includes reflecting films 61 , 62 , and 63 adhered to a working face 9 in a running direction of the scraper conveyor, where the three reflecting films are spaced at intervals equal to the intervals between the three collimators, and the reflecting film is a thin sheet coated with a metal film on the surface and having a thickness less than 1 mm. The third optical fiber circulator array 7 includes third optical fiber circulators C 1 , C 2 , and C 3 successively connected in series via an SMF. The optical path analyzer 8 is connected in series to the third optical fiber circulator array 7 via an SMF.

The first optical fiber circulator array 2 , the second optical fiber circulator array 4 , the collimator array 5 , and the third optical fiber circulator array 7 are arranged in a direction parallel to an arrangement direction of the reflecting film array 6 . A third port A 13 of the first optical fiber circulator A 1 is connected to a first port B 11 of the second optical fiber circulator B 1 ; a second port B 12 of the second optical fiber circulator B 1 is connected to the collimator 51 ; a third port B 13 of the second optical fiber circulator B 1 is connected to a first port C 11 of the third optical fiber circulator C 1 ; a third port A 23 of the first optical fiber circulator A 2 is connected to a first port B 21 of the second optical fiber circulator B 2 ; a second port B 22 of the second optical fiber circulator B 2 is connected to the collimator 52 ; a third port B 23 of the second optical fiber circulator B 2 is connected to a first port C 21 of the third optical fiber circulator C 2 ; a third port A 33 of the first optical fiber circulator A 3 is connected to a first port B 31 of the second optical fiber circulator B 3 ; a second port B 32 of the second optical fiber circulator B 3 is connected to the collimator 53 ; and a third port B 33 of the second optical fiber circulator B 3 is connected to a first port C 31 of the third optical fiber circulator C 3 .

In the first optical fiber circulator array 2 , an optical transmission path between ports A 11 and A 12 of the first optical fiber circulator A 1 is unidirectional, and an optical transmission path between the ports A 12 and A 13 of the first optical fiber circulator A 1 is unidirectional; an optical transmission path between ports A 21 and A 22 of the first optical fiber circulator A 2 is unidirectional, and an optical transmission path between the ports A 22 and A 23 of the first optical fiber circulator A 2 is unidirectional; and an optical transmission path between ports A 31 and A 32 of the first optical fiber circulator A 3 is unidirectional, and an optical transmission path between the ports A 32 and A 33 of the first optical fiber circulator A 3 is unidirectional.

In the second optical fiber circulator array 4 , an optical transmission path between the ports B 11 and B 12 of the second optical fiber circulator B 1 is unidirectional, and an optical transmission path between the ports B 12 and B 13 of the second optical fiber circulator B 1 is unidirectional; an optical transmission path between the ports B 21 and B 22 of the second optical fiber circulator B 2 is unidirectional, and an optical transmission path between the ports B 22 and B 23 of the second optical fiber circulator B 2 is unidirectional; and an optical transmission path between the ports B 31 and B 32 of the second optical fiber circulator B 3 is unidirectional, and an optical transmission path between the ports B 32 and B 33 of the second optical fiber circulator B 3 is unidirectional.

In the third optical fiber circulator array 7 , an optical transmission path between the ports C 11 and C 12 of the third optical fiber circulator C 1 is unidirectional, and an optical transmission path between the ports C 12 and C 13 of the third optical fiber circulator C 1 is unidirectional; an optical transmission path between the ports C 21 and C 22 of the third optical fiber circulator C 2 is unidirectional, and an optical transmission path between the ports C 22 and C 23 of the third optical fiber circulator C 2 is unidirectional; and an optical transmission path between the ports C 31 and C 32 of the third optical fiber circulator C 3 is unidirectional, and an optical transmission path between the ports C 32 and C 33 of the third optical fiber circulator C 3 is unidirectional.

A broadband spectrum output by the broadband light source 1 enters the first optical fiber circulator A 1 from the port A 11 of the first optical fiber circulator A 1 , and is then output from the port A 12 . The light output from the port A 12 reaches a first optical grating and light with a wavelength of λ 1 is returned. Light of the remaining wavelength is continuously transmitted forward, enters the first optical fiber circulator A 2 through the port A 21 of the first optical fiber circulator A 2 , and is output from the port A 22 . The light output from the port A 22 reaches a second optical grating and light with a wavelength of λ 2 is returned. Light of the remaining wavelength is continuously transmitted forward, enters the first optical fiber circulator A 3 through the port A 31 of the first optical fiber circulator A 3 , and is output from the port A 32 . The light output from the port A 32 reaches a third optical grating and light with a wavelength of λ 3 is returned. Light of the remaining wavelength is continuously transmitted forward.

The returned light with the wavelengths of λ 1 , λ 2 , and λ 3 enters the second optical fiber circulators B 1 , B 2 , and B 3 respectively through the port B 11 of the second optical fiber circulator B 1 , the port B 21 of the second optical fiber circulator B 2 , and the port B 31 of the second optical fiber circulator B 3 ; and then is output from the ports B 12 , B 22 , and B 32 respectively.

The light output from the ports B 12 , B 22 , and B 32 reaches the reflecting films 61 , 62 , and 63 respectively through the collimators 51 , 52 , and 53 .

The light with the wavelength of λ 1 returns back to the second optical fiber circulator B 1 via the collimator 51 through the port B 12 under the effect of the reflecting film 61 , and is output from the port B 13 . The light with the wavelength of λ 2 returns back to the second optical fiber circulator B 2 via the collimator 52 through the port B 22 under the effect of the reflecting film 62 , and is output from the port B 23 . The light with the wavelength of λ 3 returns back to the second optical fiber circulator B 3 via the collimator 53 through the port B 32 under the effect of the reflecting film 63 , and is output from the port B 33 .

The light output from the ports B 13 , B 23 , and B 33 enters the third optical fiber circulators C 1 , C 2 , and C 3 respectively through the port C 11 of the third optical fiber circulator C 1 , the port C 21 of the third optical fiber circulator C 2 , and the port C 31 of the third optical fiber circulator C 3 ; and then is output respectively through the ports C 12 , C 22 and C 32 .

The light with the wavelengths of λ 1 , λ 2 , and λ 3 output from the ports C 12 , C 22 and C 32 enters the optical path analyzer 8 via the SMF, and the optical path analyzer 8 calculates transmission distances of the different wavelengths of light, to obtain positions of the different reflecting films. Because the position points of the reflecting films are corresponding to positions on the scraper conveyor, the straightness of the working face of the scraper conveyor in the running direction can be obtained according to connecting lines between the position points.

The above merely describes a preferred embodiment of the present invention, and is not intended to limit the present invention in any form. Based on the embodiment of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the scope of protection of the present invention. Any simple modifications and equivalent changes made to the foregoing embodiment according to the technical essence of the present invention all fall within the scope of protection of the present invention.