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

Abstract

The present invention relates to the field of rotating shaft detection technology, and proposes 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 the main shaft is integrated with multiple optical fibers along the axial direction; the micro-demodulation module is arranged on one end of the main shaft and has a wireless signal transmission element; 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. The present invention arranges an optical fiber and a micro-demodulation module on the main shaft, 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, the working condition detection of the main shaft in a rotating state can be realized, so as to obtain parameters such as the deformation, vibration, and torque performance of the main shaft in actual application, and eliminate errors existing in traditional detection.

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] Rotating shaft systems are key components for transmitting power and motion in mechanical systems and are widely used in industrial production. Rotating shafts in mechanical systems need to bear external loads and torque during long-term high-speed operation. The operating state is complex, and the operating efficiency also varies with the operating state. Under the action of alternating loads, the rotating shaft will produce a certain amount of torsional deformation, which will further cause a sharp decline 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. This is of great significance for ensuring the safe and reliable operation of the shaft, the transmission performance of the system, and the processing quality of the product.

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

[0004] As in the above technical solution, the optical fiber is directly wound around the drive shaft, and the optical fiber is connected to the 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 drive shaft, which is only suitable for static torque loading detection of the drive shaft. If the drive 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 status of the drive shaft under actual working 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 as follows:

[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 multiple optical fibers are integrated along the main shaft;

[0009] The multiple optical fibers are arranged in a spiral structure, and in the radial perspective of the main axis, the optical fibers form a 45-degree angle with the axis of the main axis;

[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 ring-shaped, 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 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 the other 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 further includes a protective tube and a gasket, wherein,

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

[0020] A portion of the protection tube corresponds to the tube sleeve, and the wireless output coil is arranged on the portion 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 an annular 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 supporting piece 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 bent at the side of the connecting tube to connect to 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 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 provided on each optical fiber, and the central wavelengths of the five grating regions are increased by 3 to 5 nm in sequence;

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

[0040] The spacing angle between the grating regions of different optical fibers located on the same cross-sectional circle of the principal 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 base; L is the length of the main axis; n is the number of optical fibers; l is the axial distance 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] On the other hand, the present invention provides another rotating shaft performance verification device, comprising the above-mentioned rotating shaft 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 optical fiber sensing-based rotating shaft monitoring system and performance verification device of the present invention have the following advantages over the prior art:

[0053] (1) By arranging an optical fiber and a micro-demodulation module on the main shaft, 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, when in use, the optical fiber, the micro-demodulation module and the wireless receiving coil can rotate with the main shaft, and ensure normal power supply and signal transmission, thereby realizing the working condition detection of the main shaft in the rotating state, so as to obtain the parameters such as the deformation, vibration and torque performance of the main shaft in actual application, and eliminating the errors existing in traditional detection;

[0054] (2) By setting a fixing part, which is connected to the end of the main shaft by using a ring seat, two limiting frames arranged opposite to each other cooperate with the ring seat to form two accommodating cavities, one of which is used to install the micro-demodulation module, and the other is used to install the counterweight. In this way, 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. This makes the diameter of the tube sleeve larger than the diameter of the ring seat, and the diameter of the protective tube is larger than the diameter of the tube sleeve. This makes it convenient to set the wireless receiving coil and the wireless output coil, and makes the coil farther away from the main shaft. At the same time, the tube sleeve and the protective tube are made of insulating material, which can avoid electromagnetic interference, thereby preventing the power supply and signal transmission of the micro demodulation module from being affected;

[0056] (4) In the main shaft 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 to the micro-demodulation module. This 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 by the rotation of the main shaft on the bending 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 and avoid 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 protective 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, thereby realizing 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 protective 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 following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0060] Figure 1 A perspective view 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 This is an end view of the rotating shaft monitoring system based on optical fiber sensing of the present invention;

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

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

[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 disassembled structural diagram of the fixing parts and gaskets of the rotating shaft monitoring system based on optical fiber sensing of the present invention;

[0068] Figure 9 This is a fiber optic structure diagram of the rotating shaft monitoring system based on fiber optic sensing of the present invention;

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

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

[0071] Figure 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. Pipe sleeve; 501. Accommodating cavity; 6. Protective tube; 7. Gasket; 71. Fixing plate; 72. Support 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 embodiments described 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 making creative efforts 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 includes 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 includes the above-mentioned optical fiber sensing rotating shaft system monitoring system.

[0076] like Figure 1 、 Figure 2 and Figure 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 perspective of the main shaft 1, the optical fibers 2 form a 45-degree angle with the axis of the main shaft 1;

[0077] As shown in the above structure, the main shaft 1 is configured as a cylindrical structure. During the rotation of the main shaft 1, the cross section bears the greatest shear stress, and the inclined section at a 45-degree angle to the circumferential generatrix of the main shaft 1 has the greatest normal stress. Specifically, when a torsional force acts on the main shaft 1, 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 Figure 11 and Figure 12 As shown, the main shaft 1 is made of metal or fiber composite material. 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.

[0080] As shown in the above structure, there are two structures for the integration of the main shaft 1 and the optical fiber 2:

[0081] First, as Figure 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 Figure 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 and 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, which is conducive to ensuring the detection accuracy of the optical fiber 2.

[0083] like Figure 9 and Figure 10 As shown, each optical fiber 2 is provided with five grating regions 201, 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 between 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; where π is the angle in radians; and 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 can be ensured during the monitoring process.

[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 Figure 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 shown in the above structure, in this solution, the micro-demodulation module 3 is directly integrated on the main shaft 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 main shaft 1, thereby realizing real-time monitoring of the parameters of the main shaft 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 component stimulates the correct laser excitation according to the instructions of the main control component, and transmits it to each fiber grating sensor through the coupler; the reflected light of each fiber grating sensor is transmitted to the demodulation component through the coupler, and the demodulation component calculates the reflected light wavelength of each fiber grating sensor after photoelectric conversion; the signal wireless transmission component analyzes 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. The wavelength data changes of each point on the main shaft 1 can be displayed in real time on the monitoring interface of the host computer, realizing real-time acquisition of the wavelength signal of each point on the main shaft 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] In the above structure, in order to achieve real-time monitoring of the spindle 1, the micro demodulation module 3 needs to be powered while avoiding interference with the rotation of the spindle 1. The wireless output coil 42 is fixed relative to the spindle 1 and does not rotate with it, while the wireless receiving coil 41 is fixed to the spindle 1.

[0092] Specifically, the micro demodulation module 3 adopts a contactless inductive power supply module, namely the wireless charging module 4, which uses the principle of electromagnetic induction to transfer the power from the stationary transmitting end to the rotating receiving end through a contactless 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 changing magnetic field will magnetically couple with the receiving coil, causing the rotating receiving coil to generate an electric field. Therefore, when the receiving coil ends are closed, a current will be generated.

[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 sleeve 53. 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 cavities 501 with the ring seat 51. The micro demodulation module 3 is arranged in one accommodating cavity 501, and the other accommodating cavity 501 opposite to the micro demodulation module 3 is a counterweight cavity. The sleeve 53 is fixed relative to the ring seat 51, and the wireless receiving coil 41 is arranged on the sleeve 53, and the 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 to the main shaft 1. The ring seat 51 and the outer limit frame 52 form two accommodating cavities 501, one of which is used to install the micro-demodulation module 3 for connecting to the optical fiber 2; the other accommodating cavity 501 is used to install the counterweight, which is arranged opposite to the micro-demodulation module 3. This ensures the stability of the rotation of the main shaft 1 and prevents the rotation posture of the main shaft from being affected by the layout of the micro-demodulation module 3.

[0097] The fixing member 5 is further provided with a sleeve 53 made 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, 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 the same length;

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

[0100]

[0101] Wherein, H is the length of the ring base 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 described above, by controlling the length of the ring base 51 , interference between the lead-out optical fiber 2 and the fixing member 5 can be avoided.

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

[0104] As shown in the above structure, the sleeve 53 is connected to the ring seat 51 through the gasket 7. 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, thereby realizing wireless charging. The protection tube 6 is also made of 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. The gaskets 7 include a fixing plate 71, a supporting plate 72, and a connecting plate 73. 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 diameter of the ring seat 51; and the diameter of the protective tube 6 is larger than the cross-sectional diameter of the pipe sleeve 53.

[0107] As shown in the above structure, the gasket 7 is composed of a fixing piece 71, a supporting piece 72 and a connecting piece 73, which makes the diameter of the sleeve 53 larger than the diameter of the ring seat 51, and the diameter of the protective tube 6 is larger than the diameter of the sleeve 53. This facilitates the installation of the wireless receiving coil 41 and the wireless output coil 42, and makes the coils farther away from the main shaft 1, which can further avoid electromagnetic interference problems and prevent the power supply from being affected.

[0108] At the same time, this structural arrangement 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 Figure 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; a 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; a flange 13 is provided at each end 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 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;

[0110] As in the above structure, the optical fiber 2 is used to detect the parameters of the shaft tube 11. 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 as to facilitate the connection of the optical fiber 2.

[0111] When the spindle 1 is made of fiber composite material, since the optical fiber 2 is embedded in the spindle 1, in order to avoid damaging the outer wall of the spindle 1 and affecting the performance of the spindle 1, it is preferred that the optical fiber 2 be led out from the end of the spindle 1. In this case, the optical fiber 2 is bent at the side of the connecting tube 12 and then connected to the micro demodulation module 3.

[0112] To prevent the optical fiber 2 from being affected by light attenuation when it is bent, the optical fiber 2 can be looped around the connecting tube 12 before being connected to the micro-demodulation module 3. At the same time, since the diameter of the connecting tube 12 is small, a filler such as a foam material is provided inside to fix the portion of the optical fiber 2 outside the connecting tube 12. This effectively reduces the impact of the centrifugal force generated by the rotation of the main shaft 1 on the bent portion 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 inserted into the interior of the shaft tube 11, thereby improving the stability of the connection structure; at the same time, the ring seat 51 can be set corresponding to the inner tube 14, thereby supporting 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 an 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 Figure 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 interior of the protection tube 6; the bearing 10 is arranged on the 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 testing, 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, thereby testing 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 protective tube 6 to achieve heating of the main shaft 1. 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 use a thermal self-decoupling algorithm to eliminate the temperature influence.

[0120] If the spindle 1 is made of fiber composite material, when the optical fiber 2 is integrated into the spindle 1, the temperature should be controlled within the maximum tolerance range of the optical fiber 2 during testing to ensure normal testing and verification.

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

[0122] Furthermore, the end of the main shaft 1 away from the micro demodulation module 3 is connected to the protective 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 arranged on the 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 be semiconductor heating and cooling devices.

[0125] In practice, 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 wavelength change can be used to calculate the tensile or compressive strain at each point on the main shaft 1 during the torsion process. 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 elastic-optical coefficient of the optical fiber; ε is the strain at the center of the FBG sensor caused by the main axis deformation.

[0128] In some embodiments, the present invention utilizes MLP to realize the reconstruction of the spindle deformation, vibration and torque performance from the wavelength signal. Taking the reconstruction of the torque parameter 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 the spindle speed and the strain signal respectively, and the output layer includes 1 neural unit, corresponding to the output parameter of the torque. The number of neurons in the hidden layer is determined according to the needs. The test bench is equipped with a rotating table and a magnetic powder brake. 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 that 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 backward 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, and adjusts the network parameters to reduce the error. 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 actual torque value of a single input sample. Based on this error value, the weights are updated using stochastic gradient descent (SGD), with a maximum number of iterations set to 200. After training, a torque neural network model is obtained, enabling reconstruction of the spindle torque parameters during rotation.

[0134] In some embodiments, the present invention utilizes an FBG sensor network combined with a BP neural network to identify and locate impact damage on the shaft tube surface during spindle operation. The shaft tube is subjected to torsional loading at various speeds, and strain information at each point on the spindle is acquired via the FBG sensor network. This strain information and the corresponding damage location are used as the input and output of the neural network, establishing an intrinsic connection between the strain information and the damage location, thereby constructing a BP neural network model for shaft tube damage identification and location. The additional shaft tube strain information used for testing is independent of the training dataset and can be obtained through random loading points distinct from the training dataset.

[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. The damage states are healthy state, single hole state and multi-hole state. The output layer includes two neural units of 0 and 1, 0 represents healthy state and 1 represents damaged state. The formula for calculating 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 is selected as the loss function, and the BP neural network is trained using the stochastic gradient descent optimization algorithm. The learning rate is selected as 0.01-0.001, and the model training is finally completed to identify the spindle damage.

[0139] Specific implementation steps:

[0140] The wireless receiving coil 41 is mounted on the sleeve 53 and electrically connected to the micro-demodulation module 3. The wireless output coil 42 is mounted on the protective tube 6 and connected to a power source. The micro-demodulation module 3 is placed in the accommodating cavity 501 formed by the ring seat 51 and the limit frame 52, and a mass block is installed simultaneously for counterweighting. The sleeve 53 is then connected to the ring seat 51 via the gasket 7, and the entire assembly is then sleeved onto the end of the main shaft 1.

[0141] Then, the optical fiber 2 is wound on the main shaft 1 and 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 scope of protection of the present invention.

Claims

1. A rotating shaft monitoring system based on optical fiber sensing, characterized by: It comprises a main shaft (1), an optical fiber (2), a micro demodulation module (3), a wireless charging module (4), a fixing member (5), a protective tube (6) and a gasket (7), wherein: The main shaft (1) is a cylindrical structure, and the main shaft (1) is integrated with a plurality of optical fibers (2) along the axial direction; The plurality of optical fibers (2) are arranged in a spiral structure, and in a radial viewing angle of the main shaft (1), the optical fibers (2) and the axis of the main shaft (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) rotating 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 ring-shaped, and the wireless receiving coil (41) corresponds to the wireless output coil (42); The fixing member (5) includes a ring seat (51), a limiting frame (52) and a 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) in a relative manner, and form two accommodating cavities (501) with the ring seat (51); the micro demodulation module (3) is arranged in one of the accommodating cavities (501), and the other accommodating cavity (501) opposite to the micro demodulation module (3) is a counterweight cavity; the sleeve (53) is fixed relative to the ring seat (51), the wireless receiving coil (41) is arranged on the sleeve (53), and the sleeve (53) is made of insulating material; The protective tube (6) is made of insulating material, and the protective tube (6) 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 protective tube (6) corresponds to the tube sleeve (53), and the wireless output coil (42) is arranged on the part of the protective 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); A plurality of gaskets (7) are arranged in an annular array based on the axis of the main shaft (1), and the gaskets (7) include 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) is in contact with 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); and the diameter of the protective tube (6) is larger than the cross-sectional circular diameter of the pipe sleeve (53).

2. The rotating shaft monitoring system based on optical fiber sensing according to claim 1, 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).

3. The rotating shaft monitoring system based on optical fiber sensing according to claim 1, 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 a fiber composite material, the optical fiber (2) is embedded in a layer of the fiber composite material.

4. The rotating shaft monitoring system based on optical fiber sensing according to claim 1, characterized in that: Each optical fiber (2) is provided with five grating regions (201), and the central wavelengths of the five grating regions (201) increase sequentially by 3 to 5 nm; The plurality of optical fibers (2) are arranged at equal intervals on a cross-sectional circle of the main axis (1); The grating regions (201) of different optical fibers (2) located on the same cross-sectional circle of the main axis (1) are spaced at an angle of; wherein is the angle in radians; is the number of the optical fibers (2).

5. The rotating shaft monitoring system based on optical fiber sensing according to claim 4, 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: The ring seat (51) and the limiting frame (52) are of equal length; The length of the ring seat (51) satisfies the following relationship: ； in, is the length of the ring seat (51); is the length of the main axis (1); is the number of the optical fibers (2); It is the axial distance between two adjacent grating regions (201) on the same optical fiber (2) on the main axis (1).

6. 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 5.

7. The rotating shaft system performance verification device according to claim 6, characterized in that: It also includes 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 communicated 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).

Images