Rotating shaft system monitoring system based on optical fiber sensing and performance verification device

Abstract

The invention relates to the technical field of rotating shaft detection, and provides a rotating shaft system monitoring system based on optical fiber sensing, which comprises a main shaft, optical fibers, a miniature demodulation module and a wireless charging module, and is characterized in that the main shaft is integrated with a plurality of optical fibers along the axial direction; the miniature demodulation module is arranged at one end of the main shaft and is provided with a wireless signal transmission element; the wireless charging module comprises a wireless receiving coil which is fixed relative to the main shaft and can rotate along with the main shaft, and a wireless output coil which is fixed relative to the main shaft and does not rotate along with the main shaft. According to the invention, the optical fiber and the miniature demodulation module are arranged on the main shaft, the miniature demodulation module is provided with the wireless signal transmission element, and the miniature demodulation module is powered by the wireless charging module composed of the wireless receiving coil and the wireless output coil, so that working condition detection of the main shaft in a rotating state can be realized; therefore, parameters such as deformation, vibration and torque performance of the main shaft in actual application can be obtained, and errors existing in traditional detection can be eliminated.

Description

Technical Field

[0001] The present invention relates to the technical field of rotating shaft detection, and in particular to a rotating shaft monitoring system and a performance verification device based on optical fiber sensing. Background Art

[0002] The rotating shaft system is a key component for transmitting power and motion in mechanical systems and is widely used in industrial production. The rotating shaft in the mechanical system needs to bear the effects of external loads and torque during long-term high-speed operation. The state during operation is complex, and the operating efficiency will also change with the operating state. Under the action of alternating loads, the rotating shaft will produce a certain torsional deformation, which will further cause a sharp drop in the mechanical properties of the shaft, posing a serious threat to the safety and stability of the mechanical transmission system. Real-time monitoring of the health status of the rotating shaft system can promptly detect abnormal working conditions of the shaft, thereby providing a strong basis for subsequent mechanical fault diagnosis, which is of great significance for ensuring the safety and reliability of the shaft operation, the transmission performance of the system, and the processing quality of the product.

[0003] The invention patent application with the existing authorization announcement number CN114964029B discloses a shaft torque detection system based on optical fiber measurement technology, including an optical interferometer demodulator, an optical branching system and an optical fiber torque sensor group; the optical fiber torque sensor group includes a plurality of identical torque sensors, and the torque sensor consists of a first sensor and a second sensor; the first sensor includes a first optical fiber circulator, a first optical fiber semi-reflective mirror, a first optical fiber total reflective mirror and a first sensitive optical fiber; the second sensor includes a second optical fiber circulator, a second optical fiber semi-reflective mirror, a second optical fiber total reflective mirror and a second sensitive optical fiber.

[0004] As in the above technical solution, the optical fiber is directly wound around the transmission shaft, and the optical fiber is connected to a circulator, and then the optical detector cooperates with the computer to calculate the results; in this solution, since it is necessary to detect the stretching and compression of the optical fiber, the optical fiber needs to be in direct contact with the transmission shaft, and it is only suitable for static torque loading detection of the transmission shaft. If the transmission shaft rotates, it will cause interference and damage to the optical fiber connection structure, affecting the detection; the limitations of the above structure make this detection system unsuitable for detecting rotating shaft systems under rotating conditions, and it is impossible to achieve real-time monitoring functions, and it is impossible to know the state of the transmission shaft under actual conditions, resulting in detection errors. Summary of the invention

[0005] In view of this, the present invention proposes a rotating shaft monitoring system based on optical fiber sensing that can perform detection in a rotating state, so as to solve the problem that the existing detection system cannot be used to detect the transmission shaft in a rotating state and has detection errors.

[0006] The technical solution of the present invention is achieved in this way:

[0007] On the one hand, the present invention provides a rotating shaft monitoring system based on optical fiber sensing, comprising a main shaft, an optical fiber, a micro demodulation module and a wireless charging module, wherein:

[0008] The main shaft is a cylindrical structure, and a plurality of optical fibers are integrated along the axial direction of the main shaft;

[0009] The multiple optical fibers are arranged in a spiral structure, and in the radial viewing angle of the main axis, the optical fibers and the axis of the main axis form an angle of forty-five degrees;

[0010] The micro demodulation module is arranged on one end of the main shaft and connected to the optical fiber, and the micro demodulation module has a wireless signal transmission element;

[0011] The wireless charging module includes a wireless receiving coil fixed relative to the main shaft and capable of rotating with the main shaft, and a wireless output coil fixed relative to the main shaft and not rotating with the main shaft;

[0012] The wireless receiving coil and the wireless output coil are both in a ring shape, and the wireless receiving coil corresponds to the wireless output coil.

[0013] On the basis of the above technical solution, preferably, it further comprises a fixing member, the fixing member comprises a ring seat, a limiting frame and a pipe sleeve, wherein,

[0014] The ring seat sleeve is arranged on the main shaft and fixed to the main shaft;

[0015] Two limiting frames are arranged opposite to each other on the ring seat, and form two accommodating cavities with the ring seat;

[0016] The micro demodulation module is arranged in a receiving cavity, and another receiving cavity opposite to the micro demodulation module is a counterweight cavity;

[0017] The pipe sleeve and the ring seat are relatively fixed, the wireless receiving coil is arranged on the pipe sleeve, and the pipe sleeve is made of insulating material.

[0018] On the basis of the above technical solution, preferably, it also includes a protection tube and a gasket, wherein:

[0019] The protection tube is made of insulating material and is sleeved on the main shaft. The protection tube is relatively fixed to the main shaft and does not rotate with the main shaft.

[0020] A part of the protection tube corresponds to the tube sleeve, and the wireless output coil is arranged on the part of the protection tube corresponding to the tube sleeve;

[0021] One end of the gasket is connected to the ring seat, and the other end is connected to the pipe sleeve.

[0022] On the basis of the above technical solution, preferably, a plurality of gaskets are arranged in a ring array based on the axis of the main shaft, and the gaskets include a fixing plate, a supporting plate and a connecting plate, wherein:

[0023] The fixing plate is connected to the ring seat;

[0024] The support sheet is connected to the pipe sleeve;

[0025] One end of the connecting piece is connected to the fixing piece, and the other end is connected to the supporting piece;

[0026] The ring seat fits the outer wall of the main shaft;

[0027] The diameter of the pipe sleeve is larger than the cross-sectional diameter of the ring seat;

[0028] The diameter of the protective tube is larger than the cross-sectional diameter of the tube sleeve.

[0029] On the basis of the above technical solution, preferably, the main shaft includes a shaft tube, a connecting tube, a flange and an inner tube, wherein:

[0030] The shaft tube is a cylindrical structure, and the optical fiber and the micro demodulation module are arranged on the shaft tube;

[0031] A connecting tube is provided at each end of the shaft tube, and the local diameter of the connecting tube is smaller than the diameter of the shaft tube;

[0032] A flange is provided at each end of the two connecting pipes away from the shaft pipe;

[0033] The inner tube is connected to the connecting tube and inserted into the shaft tube;

[0034] The optical fiber is led out through the end of the shaft tube and is bent at the side of the connecting tube to connect the micro demodulation module. The surface of the connecting tube is provided with a filler to cover the lead-out part of the optical fiber.

[0035] On the basis of the above technical solution, preferably, the main shaft is made of metal material or fiber composite material, wherein:

[0036] When the main shaft is made of metal, the optical fiber is attached to the outer wall of the main shaft;

[0037] When the main shaft is made of fiber composite material, the optical fiber is embedded in the ply of the fiber composite material.

[0038] On the basis of the above technical solution, preferably, five grating regions are arranged on each optical fiber, and the central wavelengths of the five grating regions are increased by 3 to 5 nm in sequence;

[0039] A plurality of optical fibers are arranged at equal distances on a cross-sectional circle of the main axis;

[0040] The spacing angle of the grating areas of different optical fibers located on the same cross-sectional circle of the main axis is θ = 2π / n;

[0041] Where π is the angle in radians and n is the number of optical fibers.

[0042] On the basis of the above technical solution, preferably, the distance between two adjacent grating regions on the same optical fiber along the main axis is l;

[0043] The ring seat and the limit frame are of equal length;

[0044] The length of the ring seat satisfies the following relationship:

[0045]

[0046] Wherein, H is the length of the ring seat; L is the length of the main axis; n is the number of optical fibers; l is the axial spacing between two adjacent grating areas on the same optical fiber on the main axis.

[0047] On the other hand, the present invention provides a rotating shaft system performance verification device, including the above-mentioned rotating shaft system monitoring system based on optical fiber sensing.

[0048] In another aspect, the present invention provides another rotating shaft system performance verification device, comprising the above-mentioned rotating shaft system monitoring system based on optical fiber sensing, and also comprising a heating module, a cooling module and a bearing, wherein:

[0049] The heating module is arranged on the inner wall of the protection tube;

[0050] The cooling module is arranged on the outer wall of the protection tube, and the cooling module is communicated with the interior of the protection tube;

[0051] The bearing is arranged on an end of the main shaft away from the micro-demodulation module.

[0052] The rotating shaft monitoring system and performance verification device based on optical fiber sensing of the present invention have the following beneficial effects compared with the prior art:

[0053] (1) An optical fiber and a micro-demodulation module are arranged on the spindle, wherein the micro-demodulation module is provided with a wireless signal transmission element, and the micro-demodulation module is powered by a wireless charging module composed of a wireless receiving coil and a wireless output coil. In this way, when in use, the optical fiber, the micro-demodulation module and the wireless receiving coil can rotate with the spindle, and normal power supply and signal transmission are ensured, thereby realizing the working condition detection of the spindle in a rotating state, so as to obtain the deformation, vibration and torque performance parameters of the spindle in actual application, and eliminating the errors existing in traditional detection;

[0054] (2) By setting a fixing member, which is connected to the end of the main shaft by means of a ring seat, two limiting frames arranged opposite to each other cooperate with the ring seat to form two accommodating chambers, one of which is used to install the micro-demodulation module, and the other is used to install the counterweight, so that the stability of the main shaft rotation can be ensured to avoid the rotation posture of the main shaft being affected by the arrangement of the micro-demodulation module;

[0055] (3) In the fixing structure, the ring seat and the tube sleeve are connected by a gasket, which is composed of a fixing plate, a supporting plate and a connecting plate, so that the diameter of the tube sleeve is larger than the diameter of the ring seat, and the diameter of the protective tube is larger than the diameter of the tube sleeve, so that it is convenient to set the wireless receiving coil and the wireless output coil, and the coil is far away from the main shaft. At the same time, the tube sleeve and the protective tube are made of insulating materials, which can avoid electromagnetic interference, so as to prevent affecting the power supply and signal transmission of the micro demodulation module;

[0056] (4) In the spindle structure, the shaft tube and the flange are connected by a connecting tube, so that a reduced diameter structure is formed by the connecting tube. After the optical fiber is led out of the shaft tube, it can be bent on the outside of the connecting tube to connect the micro demodulation module, which leaves enough bending space for the optical fiber and can effectively prevent the optical fiber from breaking. At the same time, a filler is also provided on the side surface of the connecting tube. After the filler is wrapped around the optical fiber, it can effectively reduce the influence of the centrifugal force generated when the spindle rotates on the bent part of the optical fiber, thereby ensuring the stability of signal transmission and structural stability.

[0057] (5) By controlling the number and spacing of the grating areas of the optical fiber and the length of the ring seat in the fixture, the uniformity of the grating area layout in the optical fiber can be ensured to ensure accurate detection results, while also avoiding interference between the optical fiber and the fixture;

[0058] (6) The rotating shaft performance verification device of the present invention adopts the above-mentioned rotating shaft detection system based on optical fiber sensing, which is also provided with a heating module and a cooling module. In this way, when applied to simulation testing, the gap between the protection tube and the main shaft can be fully utilized; the heating module can heat the main shaft, and the cooling module can cool the main shaft, so as to realize the working condition monitoring of the rotating shaft under different temperature conditions, and when cooling, the cold air flow will also flow to the wireless charging module through the gap between the protection tube and the second part of the main shaft to cool the coil, thereby ensuring stable power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0060] Figure 1 A stereogram of a rotating shaft monitoring system based on optical fiber sensing according to the present invention;

[0061] Figure 2 For the present invention Figure 1 A magnified view of the structure at point A;

[0062] Figure 3 It is an end view of the rotating shaft monitoring system based on optical fiber sensing of the present invention;

[0063] Figure 4 It is a front view of the rotating shaft system monitoring system based on optical fiber sensing of the present invention;

[0064] Figure 5 For the present invention Figure 4 Middle AA section view;

[0065] Figure 6 For the present invention Figure 5 The structure of point B is enlarged;

[0066] Figure 7 An exploded diagram of the rotating shaft monitoring system based on optical fiber sensing of the present invention;

[0067] Figure 8 This is a structural diagram of the splitting of the fixing parts and gaskets of the rotating shaft system monitoring system based on optical fiber sensing of the present invention;

[0068] Fig. 9 The optical fiber structure diagram of the rotating shaft monitoring system based on optical fiber sensing of the present invention;

[0069] Fig.10 This is a fiber optic layout structure diagram of the rotating shaft monitoring system based on fiber optic sensing of the present invention when the main shaft is made of metal material;

[0070] Fig.11 This is a fiber optic layout structure diagram of the rotating shaft monitoring system based on fiber optic sensing of the present invention when the main shaft is made of composite material;

[0071] Fig.12 It is a cross-sectional view of the rotating shaft system performance verification device of the present invention.

[0072] In the figure: 1. main shaft; 11. shaft tube; 12. connecting tube; 13. flange; 14. inner tube; 2. optical fiber; 201. grating area; 3. micro demodulation module; 4. wireless charging module; 41. wireless receiving coil; 42. wireless output coil; 5. fixing part; 51. ring seat; 52. limiting frame; 53. sleeve; 501. accommodating cavity; 6. protective tube; 7. gasket; 71. fixing plate; 72. supporting plate; 73. connecting plate; 8. heating module; 9. cooling module; 10. bearing. DETAILED DESCRIPTION

[0073] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0074] like Figures 1 to 12 As shown, the optical fiber sensing rotating shaft monitoring system of the present invention comprises a main shaft 1, an optical fiber 2, a micro demodulation module 3, a wireless charging module 4, a fixing part 5, a protective tube 6 and a gasket 7;

[0075] The rotating shaft system performance verification device of the present invention comprises the above-mentioned rotating shaft system monitoring system using optical fiber sensing.

[0076] like Figure 1 , Figure 2 and Fig.10 As shown, the main shaft 1 is a cylindrical structure, and the main shaft 1 integrates multiple optical fibers 2 along the axial direction; the multiple optical fibers 2 are arranged in a spiral structure, and in the radial viewing angle of the main shaft 1, the optical fibers 2 and the axis of the main shaft 1 form an angle of 45 degrees;

[0077] As in the above structure, the main shaft 1 is set as a cylindrical structure; during the rotation of the main shaft 1, the cross section bears the maximum shear stress, and the maximum normal stress exists on the inclined section that is 45 degrees to the circumferential generatrix of the main shaft 1; specifically, when the torsional force acts on the main shaft 1, the tensile stress will occur in the 45-degree direction of the main shaft 1, and the maximum tensile stress will occur;

[0078] Based on this, the optical fiber 2 is arranged at an angle of 45 degrees to the axis of the main shaft 1, so as to achieve the measurement of strain or torque at multiple points on the main shaft 1.

[0079] like Fig.11 and Fig.12 As shown, the main shaft 1 is made of metal or fiber composite material, wherein when the main shaft 1 is made of metal, the optical fiber 2 is adhered to the outer wall of the main shaft 1; when the main shaft 1 is made of fiber composite material, the optical fiber 2 is buried in the ply of the fiber composite material;

[0080] As described above, for the integration of the main shaft 1 and the optical fiber 2, two structures are provided:

[0081] First, if Fig.10 As shown, the main shaft 1 is made of metal, and the optical fiber 2 is spirally wound on the outer wall of the main shaft 1 and fixed by bonding;

[0082] Second, if Fig.11As shown, the main shaft 1 is made of fiber composite materials. Fiber composite materials are usually formed by coating multiple layers of materials layer by layer. At this time, the optical fiber 2 can be buried in the main shaft 1. The optical fiber 2 is coated by laying layers. This can achieve better detection and avoid the optical fiber 2 falling off or vibrating due to the centrifugal force of the rotation of the main shaft 1. This is beneficial to ensure the detection accuracy of the optical fiber 2.

[0083] like Fig. 9 and Fig.10 As shown, five grating regions 201 are arranged on each optical fiber 2, and the central wavelengths of the five grating regions 201 increase by 3 to 5 nm in sequence; multiple optical fibers 2 are arranged equidistantly on the cross-sectional circle of the main axis 1; the interval angle of the grating regions 201 of different optical fibers 2 located on the same cross-sectional circle of the main axis 1 is θ=2π / n; wherein π is the angle in radians; n is the number of optical fibers 2;

[0084] As in the above structure, the optical fiber 2 is a fiber Bragg grating sensor. Taking five grating regions 201 as an example, the central wavelengths of the five grating regions 201 can be 1532nm, 1537nm, 1542nm, 1547nm and 1552nm respectively. If the central wavelengths of the grating regions 201 are different, the separation of the reflection peaks of each wavelength during the monitoring process can be ensured;

[0085] In the structure shown in the figure, five optical fibers 2 are provided. By controlling the spacing angle of the multiple optical fibers 2 to be 2π / n, the optical fibers 2 can be evenly arranged, which is conducive to achieving comprehensive and uniform detection of the main shaft 1.

[0086] like Figure 2 and Fig.11 As shown, the micro demodulation module 3 is arranged on one end of the main shaft 1 and connected to the optical fiber 2, and the micro demodulation module 3 has a wireless signal transmission element;

[0087] As described above, in this solution, the micro demodulation module 3 is directly integrated on the spindle 1. After the end of the optical fiber 2 is led out, it can be connected to the micro demodulation module 3. This structure allows the micro demodulation module 3 and the optical fiber 2 to rotate with the spindle 1 to achieve real-time monitoring of the parameters of the spindle 1.

[0088] Specifically, the micro demodulation module 3 has components such as a wireless signal transmission element, a main control element, a light source element, and a demodulation element;

[0089] Among them, the light source element stimulates the correct laser excitation according to the instruction of the main control element, and transmits it to each fiber grating sensor through the coupler; the reflected light of each fiber grating sensor is transmitted to the demodulation element through the coupler, and the demodulation element calculates the reflected light wavelength of each fiber grating sensor after photoelectric conversion; the signal wireless transmission element resolves the reflected wavelength signal into an electrical signal, and transmits the signal to the outside wirelessly in the form of electromagnetic waves; the wireless signal receiving module is used to receive the electromagnetic wave signal emitted by the micro-demodulation module, and transmit the electromagnetic wave signal to the host computer for centralized processing, and the wavelength data changes of each point on the main axis 1 can be displayed in real time on the monitoring interface of the host computer, so as to realize the real-time acquisition of the wavelength signal of each point on the main axis 1.

[0090] like Figure 2 , Figure 6 and Figure 7 As shown, the wireless charging module 4 includes a wireless receiving coil 41 fixed relative to the main shaft 1 and capable of rotating with the main shaft 1, and a wireless output coil 42 fixed relative to the main shaft 1 and not rotating with the main shaft 1; the wireless receiving coil 41 and the wireless output coil 42 are both ring-shaped, and the wireless receiving coil 41 corresponds to the wireless output coil 42;

[0091] As in the above structure, in order to realize real-time monitoring of the spindle 1, the micro demodulation module 3 needs to be powered, and at the same time, it is necessary to avoid interference with the rotation of the spindle 1; wherein the wireless output coil 42 is fixed relative to the spindle 1 and does not rotate with it, and the wireless receiving coil 41 is fixed on the spindle 1;

[0092] Specifically, the micro demodulation module 3 adopts a non-contact inductive power supply module, namely, a wireless charging module 4, which uses the principle of electromagnetic induction to transfer the electric energy of the stationary transmitting end to the rotating receiving end through a non-contact coupling method;

[0093] When an alternating current passes through the stationary transmitting coil, an alternating electric field is generated. The alternating electric field will generate a changing magnetic field through the transmitting coil. The magnetic coupling effect of the changing magnetic field on the receiving coil causes the rotating receiving coil to generate an electric field, so that a current will be generated after the receiving coil end is closed.

[0094] By connecting the interface of the wireless receiving coil 41 to the micro demodulation module 3 , wireless power supply to the micro demodulation module 3 can be realized in real time during the rotation of the main shaft 1 .

[0095] like Figures 3 to 8As shown, the fixing member 5 includes a ring seat 51, a limiting frame 52 and a pipe sleeve 53, wherein the ring seat 51 is sleeved on the main shaft 1 and fixed to the main shaft 1; two limiting frames 52 are arranged on the ring seat 51 opposite to each other, and form two accommodating chambers 501 with the ring seat 51; the micro demodulation module 3 is arranged in one accommodating chamber 501, and the other accommodating chamber 501 opposite to the micro demodulation module 3 is a counterweight chamber; the pipe sleeve 53 is fixed relatively to the ring seat 51, and the wireless receiving coil 41 is arranged on the pipe sleeve 53, and the pipe sleeve 53 is made of insulating material;

[0096] As shown in the above structure, the fixing member 5 is used to integrate the micro demodulation module 3 and the wireless charging module 4; the ring seat 51 of the fixing member 5 is used to connect the main shaft 1, and the ring seat 51 and the outer limiting frame 52 form two accommodating chambers 501, one of which is used to install the micro demodulation module 3 to connect the optical fiber 2; the other accommodating chamber 501 is used to install the counterweight, and the counterweight is arranged opposite to the micro demodulation module 3, so as to ensure the stability of the rotation of the main shaft 1, so as to avoid the rotation posture of the main shaft being affected by the arrangement of the micro demodulation module 3;

[0097] The fixing member 5 is also provided with a sleeve 53 of insulating material, and the sleeve 53 is used to install the wireless receiving coil 41 in the wireless charging module 4. When the main shaft 1 is made of metal material, this can avoid electromagnetic interference problems.

[0098] The distance between two adjacent grating regions 201 on the same optical fiber 2 along the axial direction of the main axis 1 is l; the ring seat 51 and the limit frame 52 are of equal length;

[0099] The length of the ring seat 51 satisfies the following relationship:

[0100]

[0101] Wherein, H is the length of the ring seat 51; L is the length of the main axis 1; n is the number of optical fibers 2; l is the axial distance between two adjacent grating regions 201 on the same optical fiber 2 on the main axis 1;

[0102] As in the above structure, by controlling the length of the ring base 51, it is possible to avoid interference between the lead-out optical fiber 2 and the fixing member 5.

[0103] like Figure 5 and Figure 6 As shown, the protection tube 6 is made of insulating material, and the protection tube 6 is sleeved on the main shaft 1. The protection tube 6 is relatively fixed to the main shaft 1 and does not rotate with the main shaft 1. A part of the protection tube 6 corresponds to the tube sleeve 53, and the wireless output coil 42 is arranged on the part of the protection tube 6 corresponding to the tube sleeve 53. One end of the gasket 7 is connected to the ring seat 51, and the other end is connected to the tube sleeve 53.

[0104] As in the above structure, the sleeve 53 is connected to the ring seat 51 through the gasket 7, and the protective tube 6 is used to isolate the main shaft 1 from the external environment and is also used to install the wireless output coil 42 of the wireless charging module 4. The wireless output coil 42 is bonded to the outer ring surface of the protective tube 6;

[0105] Among them, the protection tube 6 partially corresponds to the tube sleeve 53, so that the wireless receiving coil 41 and the wireless output coil 42 can correspond to each other, so as to realize wireless charging. The protection tube 6 also adopts insulating material to avoid electromagnetic interference.

[0106] like Figure 8 As shown, a plurality of gaskets 7 are arranged in an annular array based on the axis of the main shaft 1, and the gasket 7 includes a fixing plate 71, a supporting plate 72 and a connecting plate 73, wherein the fixing plate 71 is connected to the ring seat 51; the supporting plate 72 is connected to the pipe sleeve 53; one end of the connecting plate 73 is connected to the fixing plate 71, and the other end is connected to the supporting plate 72; the ring seat 51 fits the outer wall of the main shaft 1; the diameter of the pipe sleeve 53 is larger than the cross-sectional circular diameter of the ring seat 51; the diameter of the protective tube 6 is larger than the cross-sectional circular diameter of the pipe sleeve 53;

[0107] As shown in the above structure, the gasket 7 is composed of a fixing plate 71, a supporting plate 72 and a connecting plate 73, so that the diameter of the tube sleeve 53 is larger than the diameter of the ring seat 51, and the diameter of the protection tube 6 is larger than the diameter of the tube sleeve 53, so that it is convenient to set the wireless receiving coil 41 and the wireless output coil 42, and make the coil far away from the main shaft 1, which can further avoid the problem of electromagnetic interference to prevent affecting the power supply;

[0108] At the same time, the arrangement of this structure forms a concentric annular gap between the sleeve 53 and the ring seat 51, which facilitates the lead-out connection of the optical fiber 2 and avoids interference with the wireless receiving coil 41.

[0109] like Figure 6 and Fig.11 As shown, the main shaft 1 includes a shaft tube 11, a connecting tube 12, a flange 13 and an inner tube 14, wherein the shaft tube 11 is a cylindrical structure, and the optical fiber 2 and the micro demodulation module 3 are arranged on the shaft tube 11; the connecting tube 12 is respectively arranged at both ends of the shaft tube 11, and the local diameter of the connecting tube 12 is smaller than the diameter of the shaft tube 11; the flange 13 is respectively arranged at the ends of the two connecting tubes 12 away from the shaft tube 11; the inner tube 14 is connected to the connecting tube 12 and inserted into the shaft tube 11; the optical fiber 2 is led out through the end of the shaft tube 11, and is bent at the side of the connecting tube 12 to connect the micro demodulation module 3, and the surface of the connecting tube 12 is provided with a filler to cover the lead-out part of the optical fiber 2;

[0110] As in the above structure, the optical fiber 2 is used to detect the parameters of the shaft tube 11, and the shaft tube 11 is made of metal or fiber composite material, and then connected to the flange 13 through the connecting tube 12; in this structure, the diameter of the connecting tube 12 is set to be smaller than the diameter of the shaft tube 11. When the main shaft 1 is made of metal, the optical fiber interface of the micro demodulation module 3 can be set to face the middle section of the main shaft 1, so that it is convenient to connect the optical fiber 2;

[0111] When the main shaft 1 is made of fiber composite material, since the optical fiber 2 is buried inside the main shaft 1, in order to avoid damaging the outer wall of the main shaft 1 and affecting the performance of the main shaft 1, it is preferred to lead the optical fiber 2 out from the end of the main shaft 1. At this time, the optical fiber 2 is bent at the side of the connecting tube 12 and then connected to the micro demodulation module 3;

[0112] In order to avoid the influence of light attenuation on the detection when the optical fiber 2 is bent, the optical fiber 2 can be connected to the micro demodulation module 3 after it is wrapped around the connecting tube 12 for one circle; at the same time, since the diameter of the connecting tube 12 is small, a filler such as a foaming material is arranged inside to fix the part of the optical fiber 2 located outside the connecting tube 12, thereby effectively reducing the influence of the centrifugal force generated when the main shaft 1 rotates on the bent part of the optical fiber 2, thereby ensuring the stability of signal transmission and structural stability;

[0113] In this structure, an inner tube 14 is also provided, which is plugged into the interior of the shaft tube 11, so as to improve the stability of the connection structure; at the same time, the ring seat 51 can be arranged corresponding to the inner tube 14, so as to support the shaft tube 11; under the support of the inner tube 14, the part of the shaft tube 11 corresponding to the inner tube 14 does not need to be equipped with the optical fiber 2 for detection, which facilitates the installation of the ring seat 51;

[0114] Adaptively, the connecting tube 12 and the inner tube 14 may be grooved or opened in a targeted manner to allow the optical fiber 2 to be led out and connected to the micro demodulation module 3 .

[0115] like Fig.12 As shown, the rotating shaft system performance verification device of the present invention further includes a heating module 8, a cooling module 9 and a bearing 10, wherein the heating module 8 is arranged on the inner wall of the protection tube 6; the cooling module 9 is arranged on the outer wall of the protection tube 6, and the cooling module 9 is communicated with the inside of the protection tube 6; the bearing 10 is arranged on one end of the main shaft 1 away from the micro demodulation module 3;

[0116] As described above, the rotating shaft system performance verification device of the present invention is suitable for detecting and verifying the performance of the rotating shaft;

[0117] During the test, in order to simulate the application state of the spindle 1 under different working conditions, a heating module 8 and a cooling module 9 are provided to adjust the temperature of the spindle 1, so as to test the performance of the spindle 1 under different temperature environments;

[0118] Since the protection tube 6 is sleeved with the main shaft 1, the space between the two is convenient for arranging the heating module 8 and / or the cooling module 9;

[0119] Specifically, the heating module 8 can be an electric heating wire assembly and is arranged on the inner wall of the protection tube 6 to achieve heating of the main shaft 1; wherein, if the optical fiber 2 is arranged on the outer wall of the main shaft 1, it is coated with an insulating material to avoid temperature influence; at the same time, the optical fiber 2 can adopt a thermal self-decoupling algorithm to eliminate the temperature influence;

[0120] If the main shaft 1 is made of fiber composite material, when the optical fiber 2 is integrated in the main shaft 1, the temperature is controlled within the maximum tolerance range of the optical fiber 2 during testing to ensure the normal testing and verification work;

[0121] Specifically, the cooling module 9 can adopt a cooling pipeline to control the spindle 1 to be in a low-temperature environment by sending a low-temperature airflow; at the same time, the cooling airflow will flow through the space between the protection tube 6 and the spindle 1 and be discharged through the end, thereby realizing the cooling of the wireless charging module 4 and the micro demodulation module 3 simultaneously;

[0122] Furthermore, one end of the main shaft 1 away from the micro demodulation module 3 is connected to the protection tube 6 through the bearing 10, which realizes the end sealing, is conducive to temperature control, and is also conducive to cooling the wireless charging module 4 and the micro demodulation module 3;

[0123] During the heating operation, the bearing 10 may be disposed on an end of the main shaft 1 close to the micro-demodulation module 3 .

[0124] In some embodiments, the heating module 8 and the cooling module 9 may use semiconductor heating and cooling devices.

[0125] In application, when the main shaft 1 is subjected to torque, the torsion and deformation of the main shaft 1 will cause the central wavelength of the FBG sensor to change. The tensile or compressive strain of each point on the main shaft 1 during the torsion process can be calculated with the help of the wavelength change. Under constant temperature conditions, the formula for the central wavelength change of the FBG sensor can be expressed as:

[0126] λ B =λ B0 +λ B0 (1-P e )·ε

[0127] Where: B0 is the central wavelength of the FBG sensor when it is not under force; B P is the wavelength change of the FBG sensor at the next moment caused by the deformation of the main axis 1; e is the optical fiber elastic coefficient; ε is the strain at the center of the FBG sensor caused by the main axis deformation.

[0128] In some embodiments, the present invention uses MLP to achieve reconstruction of spindle deformation, vibration and torque performance by wavelength signals. Taking the reconstruction of torque parameters as an example, the MLP includes an input layer, a hidden layer and an output layer; the input layer contains 2 neurons, corresponding to the two input parameters of spindle speed and strain signal respectively, and the output layer includes 1 neural unit, corresponding to the output parameter of torque, and the number of neurons in the hidden layer is determined according to needs. The rotating table and the magnetic powder brake are mounted on the test bench. The rotating table can control the spindle speed, and the magnetic powder brake can control the magnitude of the applied torque. The spindle is installed on the test bench, and the test bench is used to obtain the torque corresponding to the spindle at different speeds and the strain at the point to construct a data set; the iterative calculation of the torque is:

[0129] y1=w1*x1+w2*x2+b

[0130] Where w is the weight, x is the input parameter, and b is the bias term.

[0131] In the forward propagation process, the speed and strain values ​​enter the network from the input layer, and then pass through each layer to obtain the final output layer result. The reverse propagation process calculates the error between the output layer and the expected value, that is, the difference between the optimal torque and the torque of the forward iteration to adjust the network parameters, so that the error becomes smaller. The error calculation formula is:

[0132]

[0133] Where N is the batch, is the optimal torque value output by the output layer, y i is the real torque value in the input single sample information. According to the above error value, the weight is updated by stochastic gradient descent (SGD), and the maximum number of iterations is set to 200. After training, a torque neural network model is obtained to realize the reconstruction of the spindle torque parameters in the rotating state.

[0134] In some embodiments, the present invention can realize the identification and location of impact damage on the surface of the shaft tube during the operation of the main shaft by combining the FBG sensor network with the BP neural network. The shaft tube is subjected to torsion loading at different speeds, and the strain information of each point of the main shaft is obtained through the FBG sensor network. The strain information and the corresponding damage position state are used as the input and output of the neural network respectively, and the internal connection between the strain information and the damage position is established, thereby constructing a BP neural network model for shaft tube damage identification and location. Among them, the additional shaft tube strain information used for testing is independent of the training data set, and can be obtained through random loading points that are different from the training data set.

[0135] The input value is normalized and limited to (0,1). To facilitate the identification of the output value, it is set to 0 / 1. In this embodiment, the grating sensor network used has a total of 20 FBG gratings. The data collected by these 20 gratings are processed to form the input of the neural network, so the number of input neurons is 20; two damage points are randomly selected as the main identification points, and the damage states are healthy state, single hole state and multi-hole state. The output layer includes 2 neural units of 0 and 1, 0 represents the healthy state, and 1 represents the damaged state. The calculation formula for the number of hidden layer neurons is:

[0136]

[0137] Among them, S is the number of neurons in the hidden layer, m is the number of neurons in the input layer, n is the number of neurons in the output layer, and N S is the number of learning samples.

[0138] The cross entropy function was selected as the loss function, and the BP neural network was trained using the stochastic gradient descent optimization algorithm. The learning rate was selected as 0.01-0.001, and finally the model training was completed to identify the spindle damage.

[0139] Specific implementation steps:

[0140] The wireless receiving coil 41 is arranged on the tube sleeve 53 and electrically connected to the micro demodulation module 3; the wireless output coil 42 is arranged on the protection tube 6 and connected to the power supply; the micro demodulation module 3 is arranged in the accommodating cavity 501 formed by the ring seat 51 and the limit frame 52, and the mass block is installed synchronously for counterweight; then the tube sleeve 53 is connected to the ring seat 51 through the gasket 7, and then the whole is sleeved to the end of the main shaft 1;

[0141] Then, the optical fiber 2 is wound on the main shaft 1, and the optical fiber 2 is connected to the micro demodulation module 3. After that, when the main shaft 1 is working, monitoring can be achieved through the optical fiber 2;

[0142] The assembly steps of the monitoring system of the present invention are not limited to the above steps, and can be adaptively adjusted according to integration requirements; for example, when the main shaft 1 is made of fiber composite material, the main shaft 1 is first integrated with the optical fiber 2.

[0143] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A rotating shaft monitoring system based on optical fiber sensing, characterized in that: It comprises a main shaft (1), an optical fiber (2), a micro demodulation module (3) and a wireless charging module (4), wherein: The main shaft (1) is a cylindrical structure, and a plurality of optical fibers (2) are integrated along the axial direction of the main shaft (1); The plurality of optical fibers (2) are arranged in a spiral structure, and in a radial viewing angle of the main axis (1), the optical fibers (2) and the axis of the main axis (1) form an angle of forty-five degrees; The micro-demodulation module (3) is arranged on one end of the main shaft (1) and is connected to the optical fiber (2), and the micro-demodulation module (3) has a wireless signal transmission element; The wireless charging module (4) comprises a wireless receiving coil (41) fixed relative to the main shaft (1) and capable of rotating along with the main shaft (1), and a wireless output coil (42) fixed relative to the main shaft (1) and not rotating along with the main shaft (1); The wireless receiving coil (41) and the wireless output coil (42) are both in a ring shape, and the wireless receiving coil (41) corresponds to the wireless output coil (42).

2. The rotating shaft monitoring system based on optical fiber sensing according to claim 1, characterized in that: It also includes a fixing member (5), the fixing member (5) including a ring seat (51), a limiting frame (52) and a pipe sleeve (53), wherein: The ring seat (51) is sleeved on the main shaft (1) and fixed to the main shaft (1); Two of the limiting frames (52) are arranged opposite to each other on the ring seat (51), and form two accommodating cavities (501) with the ring seat (51); The micro demodulation module (3) is arranged in one of the accommodating chambers (501), and the other accommodating chamber (501) opposite to the micro demodulation module (3) is a counterweight chamber; The tube sleeve (53) is relatively fixed to the ring seat (51), the wireless receiving coil (41) is arranged on the tube sleeve (53), and the tube sleeve (53) is made of insulating material.

3. The rotating shaft monitoring system based on optical fiber sensing according to claim 2, characterized in that: It also includes a protective tube (6) and a gasket (7), wherein: The protective tube (6) is made of an insulating material, and is sleeved on the main shaft (1). The protective tube (6) and the main shaft (1) are relatively fixed and do not rotate with the main shaft (1); A part of the protection tube (6) corresponds to the tube sleeve (53), and the wireless output coil (42) is arranged on the part of the protection tube (6) corresponding to the tube sleeve (53); One end of the gasket (7) is connected to the ring seat (51), and the other end is connected to the pipe sleeve (53).

4. The rotating shaft monitoring system based on optical fiber sensing according to claim 3, characterized in that: A plurality of gaskets (7) are arranged in a ring array based on the axis of the main shaft (1), and the gasket (7) comprises a fixing plate (71), a supporting plate (72) and a connecting plate (73), wherein: The fixing plate (71) is connected to the ring seat (51); The support sheet (72) is connected to the pipe sleeve (53); One end of the connecting sheet (73) is connected to the fixing sheet (71), and the other end is connected to the supporting sheet (72); The ring seat (51) is in contact with the outer wall of the main shaft (1); The diameter of the pipe sleeve (53) is greater than the cross-sectional diameter of the ring seat (51); The diameter of the protective tube (6) is greater than the cross-sectional circular diameter of the tube sleeve (53).

5. The rotating shaft monitoring system based on optical fiber sensing according to any one of claims 1 to 4, characterized in that: The main shaft (1) comprises a shaft tube (11), a connecting tube (12), a flange (13) and an inner tube (14), wherein: The shaft tube (11) is a cylindrical structure, and the optical fiber (2) and the micro demodulation module (3) are arranged on the shaft tube (11); The connecting tube (12) is provided at each end of the shaft tube (11), and the local diameter of the connecting tube (12) is smaller than the diameter of the shaft tube (11); The flange (13) is provided at each end of the two connecting pipes (12) away from the shaft pipe (11); The inner tube (14) is connected to the connecting tube (12) and inserted into the shaft tube (11); The optical fiber (2) is led out through the end of the shaft tube (11) and is bent at the side of the connecting tube (12) to connect to the micro demodulation module (3), and a filler is provided on the surface of the connecting tube (12) to cover the lead-out portion of the optical fiber (2).

6. The rotating shaft monitoring system based on optical fiber sensing according to any one of claims 1 to 4, characterized in that: The main shaft (1) is made of metal or fiber composite material, wherein: When the main shaft (1) is made of metal, the optical fiber (2) is adhered to the outer wall of the main shaft (1); When the main shaft (1) is made of fiber composite material, the optical fiber (2) is embedded in the ply of the fiber composite material.

7. The rotating shaft monitoring system based on optical fiber sensing according to any one of claims 2 to 4, characterized in that: Each of the optical fibers (2) is provided with five grating regions (201), and the central wavelengths of the five grating regions (201) are sequentially increased by 3 to 5 nm; The plurality of optical fibers (2) are arranged at equal distances on a cross-sectional circle of the main axis (1); The grating regions (201) of different optical fibers (2) are located on the same cross-sectional circle of the main axis (1) and the interval angle is θ=2π / n; Wherein, π is the angle in radians; and n is the number of the optical fibers (2).

8. The rotating shaft monitoring system based on optical fiber sensing according to claim 7, characterized in that: The distance between two adjacent grating regions (201) on the same optical fiber (2) along the axial direction of the main axis (1) is l; The ring seat (51) and the limiting frame (52) are of equal length; The length of the ring seat (51) satisfies the following relationship: Wherein, H is the length of the ring seat (51); L is the length of the main axis (1); n is the number of the optical fibers (2); and l is the axial spacing between two adjacent grating regions (201) on the same optical fiber (2) on the main axis (1).

9. A rotating shaft system performance verification device, characterized in that: It comprises a rotating shaft monitoring system based on optical fiber sensing as described in any one of claims 1 to 8.

10. A rotating shaft system performance verification device, characterized in that: The rotating shaft monitoring system based on optical fiber sensing as claimed in claim 4 further comprises a heating module (8), a cooling module (9) and a bearing (10), wherein: The heating module (8) is arranged on the inner and outer walls of the protection tube (6); The cooling module (9) is arranged on the outer wall of the protection tube (6), and the cooling module (9) is in communication with the interior of the protection tube (6); The bearing (10) is arranged on an end of the main shaft (1) away from the micro demodulation module (3).

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