A wind turbine pitch bearing fault simulation experimental platform and monitoring method

Abstract

The present invention provides a wind turbine pitch bearing fault simulation experimental platform and monitoring method, which relates to the technical field of wind turbine equipment. The platform can equivalently simulate the operation and load state of the pitch bearing, realize multiple loading modes such as axial, radial and torsional, and monitor its vibration signal, sound signal and strain signal in real time under different load conditions. By analyzing the vibration signal, sound signal and strain signal, various damage characteristics of prefabricated fault slewing bearings are obtained, thereby realizing health diagnosis and fault warning of the wind turbine pitch bearing components.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine equipment, and in particular to a wind turbine pitch bearing fault simulation experimental platform and a monitoring method. Background Art

[0002] With the national goals of "carbon peak" and "carbon neutrality," my country's energy structure transformation efforts are bound to be prioritized. Wind power, as an important clean energy source, plays a crucial role in reducing carbon emissions. Driven by the "dual carbon" goals, wind turbine technology is increasingly being prioritized by the country. High-power onshore and shallow-water wind turbines, as well as deep-sea floating wind turbines, are experiencing significant development opportunities, and wind turbine installation capacity is skyrocketing across the country. According to statistics from the National Energy Administration, my country's newly installed renewable energy capacity in 2022 was 152 million kilowatts, accounting for 76.2% of the country's newly installed power generation capacity, making it the main source of new installed power capacity in my country. Wind power added 37.63 million kilowatts, bringing the cumulative installed capacity to 365 million kilowatts.

[0003] Pitch bearings, installed between the blades and the hub of a wind turbine, connect the rotor hub and blades, control the blades' windward angle, and ultimately control the rotor speed and turbine output power. Pitch bearings operate under complex conditions and generally require excellent wear resistance, corrosion resistance, self-sealing properties, UV resistance, and impact resistance to meet long-term operational requirements under high shock loads and alternating stresses. During wind turbine operation, pitch bearing speed typically does not exceed 5 rpm, representing incomplete rotation (rotation range: 0°-90°, with a normal rotation angle of 0°-25°). However, the loads they withstand are complex, including radial and axial loads, as well as significant overturning moments generated by the turbine blade moment arm. Due to frequent heavy loads and complex environmental factors, pitch bearings are susceptible to fracture, wear, and bonding. Damage or failure of the pitch bearings can cause blade rotational imbalance, resulting in reduced generator output power. In severe cases, they can even lead to bearing fracture, potentially catastrophic for the generator and the entire wind turbine system. At present, the formation mechanism of pitch bearing failure is still unclear. Therefore, theoretical analysis and experimental simulation are used to explore the failure mechanism of pitch bearing. At the same time, combined with advanced sensors, data transmission, fault diagnosis and data model technologies, a wind turbine pitch bearing failure simulation experimental platform and monitoring method are developed. It is of great significance for the accurate and reliable fault monitoring and early warning of pitch bearings and the improvement of maintenance efficiency during the operation stage of wind turbines.

[0004] Patent No. CN202310467067.5 discloses a bearing fault simulation test bench. By setting up load-bearing units that can carry different weights and matching them with different weight counterweights, the vibration response of the bearing under different loads can be simulated. Equipped with bearing components with multiple fault types and severities, the device can simulate the vibration response of the bearing under different fault conditions. However, this device can only detect vibration response and cannot detect signals such as sound and strain. Patent No. CN202122419630.0 discloses a rolling bearing fault simulation test bench. This test bench is coaxially adjustable to prevent motor vibration from affecting bearing fault testing. A tension adjustment mechanism ensures that the test data of the bearing test assembly is clear. At the same time, it can combine and study multiple mechanical faults. However, this device only involves radial loading. In actual working conditions, the loading mode of the bearing is mostly a composite loading mode. Patent No. CN202311074525.5 discloses a device related to bearing testing technology, specifically a device for loading bearings with outer ring rotation. This device can simulate complex operating conditions such as outer ring rotation, radial loads, and bending moment loading, but it does not address axial loading. The main issues with existing bearing fault simulation test benches are that, in addition to vibration signals, other signals such as sound and strain are not captured. Furthermore, the loading conditions are mostly single radial loading, with no consideration of axial or combined loading. Summary of the Invention

[0005] In order to address the deficiencies of the above-mentioned prior art, the present invention provides a wind turbine pitch bearing fault simulation experimental platform and monitoring method, which can equivalently simulate the operation and load state of the pitch bearing, realize multiple loading modes such as axial, radial and torsional, and monitor its vibration signal, sound signal and strain signal in real time under different load conditions. By analyzing the vibration signal, sound signal and strain signal, various damage characteristics of prefabricated fault slewing bearings are obtained, thereby realizing health diagnosis and fault warning of the wind turbine pitch bearing components.

[0006] The present invention is achieved through the following technical solutions:

[0007] A wind turbine variable pitch bearing fault simulation experimental platform is characterized by comprising: a simulated blade, a control system, and a base platform, wherein a support frame is provided on the base platform, a radial second displacement frame is assembled in the support frame, a radial first displacement frame is movably assembled in the radial second displacement frame via radial first displacement guide pillars, the radial first displacement frame is connected to a radial first loading assembly, and the radial first loading assembly drives the radial first displacement frame to move in a second direction in the radial second displacement frame; a radial first displacement block is assembled in the radial first displacement frame via radial second displacement guide pillars, and the radial first displacement block is connected to the radial second loading assembly, and the radial second loading assembly drives the radial first displacement block to move in a first direction in the radial first displacement frame along the radial second displacement guide pillars; the first direction and the second direction are perpendicular; one end of the simulated blade is assembled in the radial first displacement block and connected to the torque loading assembly, and the other end is connected to a slewing bearing, connected to a drive assembly, and supported by a slewing bearing seat; a collection assembly is assembled on the slewing bearing; a torque loading support is provided outside the torque loading assembly, one end of the torque loading support is connected to the axial loading assembly via an axial loading universal block, and the other end is connected to the simulated blade.

[0008] Furthermore, the first radial displacement block contacts the upper and lower ends of the first radial displacement frame.

[0009] Furthermore, the radial second displacement frame is assembled in the support frame through the axial displacement guide column; one end of the simulated blade is assembled in the radial first displacement block through a fixed bearing.

[0010] Furthermore, the torque loading assembly includes a torque motor and a planetary reducer I, the torque motor is connected to the planetary reducer I, the planetary reducer I is connected to the simulated blade through a coupling and a connecting rod, and a torque speed sensor is assembled on the connecting rod.

[0011] Furthermore, the radial first loading component adopts electric cylinder I; the radial second loading component adopts electric cylinder II; and the axial loading component adopts electric cylinder III.

[0012] Furthermore, the telescopic rod of the electric cylinder I is equipped with a tension and pressure sensor I; the telescopic rod of the electric cylinder II is equipped with a tension and pressure sensor II, and the telescopic rod of the electric cylinder III is equipped with a tension and pressure sensor III.

[0013] Furthermore, the acquisition component includes a vibration signal acquisition component, a strain signal acquisition component and a sound acquisition component.

[0014] Furthermore, the vibration signal acquisition component includes a vibration sensor and a 24-channel vibration collector; the strain signal acquisition component includes an optical fiber sensor and a demodulator; and the sound acquisition component includes a sound sensor.

[0015] Furthermore, the drive assembly includes a drive motor and a planetary reducer II. The drive motor is connected to the planetary reducer II. The planetary reducer II drives the simulated blade to rotate by cooperating with the gear in the slewing bearing through the drive pinion.

[0016] A wind turbine pitch bearing fault simulation experiment monitoring method includes the following steps:

[0017] Step 1: Start the experimental platform to apply torque loading, axial loading, radial horizontal loading, and vertical loading to the simulated blade;

[0018] Step 2: collecting the vibration signal, strain signal, and sound signal of the slewing bearing during the loading process in step 1 through the acquisition component, and transmitting the collected signals to the control system to obtain the main frequencies of the measured vibration signal, strain signal, and sound signal;

[0019] Step 3: Calculate the characteristic frequency using the fault characteristic frequency formula. The fault characteristic frequency formula is as follows:

[0020] Outer race fault characteristic frequency:

[0021] ;

[0022] Inner race fault characteristic frequency:

[0023] ;

[0024] Rolling element failure characteristic frequency:

[0025] ;

[0026] Cage failure characteristic frequency:

[0027] ;

[0028] in is the number of rolling elements, is the rolling element diameter, is the raceway pitch diameter, is the bearing contact angle, Indicates frequency conversion;

[0029] Step 4: If the characteristic frequency obtained in step 3 matches one or more main frequencies in the signal measured in step 2, the fault location can be obtained.

[0030] The working principle of the present invention is as follows:

[0031] The simulated blades and the slewing bearings rotate under the drive of the driving assembly, and the torque loading assembly is connected to the simulated blades, so that the torque load is directly transmitted to the simulated blades, thereby realizing torque loading on the simulated blades; the radial first displacement frame is connected to the radial first loading assembly, and the radial first loading assembly drives the radial first displacement frame to move along the second direction in the radial second displacement frame, and contacts the radial first displacement block, and transfers the load equally from the radial first displacement frame to the radial first displacement block, and from the radial first displacement block to the simulated blades, thereby realizing load application on the simulated blades in the second direction; the radial first displacement block is assembled in the radial first displacement frame through the radial second displacement guide column, and the radial first displacement block is connected to the radial second loading assembly and driven by the radial second loading assembly The radial first displacement block moves along the radial second displacement guide column along the first direction in the radial first displacement frame, and the simulated blade will have a slight deformation. The load is equally transferred to the simulated blade by the radial first displacement block; the axial loading component applies axial thrust to the torque loading support through the axial loading universal block. Since the torque loading support is connected to the simulated blade, the axial loading of the simulated blade is realized. The vibration signal, strain signal and sound signal of the slewing bearing in different axial and radial directions and torque and other load processes of the slewing bearing are collected through the acquisition component and transmitted to the control system. Then, the control system calculates and analyzes the characteristic frequency through the fault analysis frequency formula and matches it with one or more main frequencies of the measured vibration signal, strain signal and sound signal, so as to obtain the specific fault position of the bearing.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. It can simulate the operation and load status of pitch bearings, and monitor their vibration, sound, and strain signals in real time under different load conditions, such as axial, radial, and torsional loads. By analyzing these signals, it can obtain various damage characteristics of pre-fault slewing bearings, thereby realizing health diagnosis and fault warning of wind turbine pitch bearing components.

[0034] 2. The present invention utilizes a radial first displacement frame, a radial second displacement frame, a support frame, and a radial first displacement block. Through nesting between the frames, a more compact structure is used to achieve torque loading, axial loading, radial horizontal loading, and vertical loading, achieving four-degree-of-freedom composite loading, closer to actual working conditions.

[0035] 3. In the present invention, multiple loading modes can be loaded independently or in combination through nesting between frames, and the four loading modes do not affect each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic diagram of the structure of the present invention;

[0037] Figure 2 for Figure 1 Front view;

[0038] Figure 3 for Figure 1 Top view;

[0039] Figure 4 for Figure 1 Schematic diagram of the middle part structure;

[0040] Figure 5 This is a health diagram of the monitoring status of the present invention;

[0041] Figure 6 This is a schematic diagram of a monitoring status failure of the present invention.

[0042] Figure markings: 1-base platform, 2-drive motor, 3-planetary reducer II, 4-slewing bearing seat, 5-slewing bearing, 6-drive pinion, 7-simulated blade, 8-radial second loading assembly, 9-support frame, 10-radial first loading assembly, 11-pull pressure sensor I, 12-coupling, 13-planetary reducer I, 14-torque motor, 15-torque loading support, 16-axial loading universal block, 17-pull pressure sensor III, 18-axial loading assembly, 19-axial loading bracket, 20-torque speed sensor, 21-pull pressure sensor II, 22-vibration sensor, 23-optical fiber sensor, 24-sound sensor, 25-axial displacement guide column, 26-radial first displacement block, 27-radial second displacement frame, 28-radial first displacement guide column, 29-radial first displacement frame, 30-fixed bearing, 31-radial second displacement guide column, 32-connecting rod. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the present invention specification. 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 making creative efforts are within the scope of protection of the present invention.

[0044] Example 1

[0045] like Figures 1-4As shown, a wind turbine variable pitch bearing fault simulation experimental platform includes a simulated blade 7, a control system, and a basic platform 1. A support frame 9 is provided on the basic platform 1. A radial second displacement frame 27 is assembled in the support frame 9. A radial first displacement frame 29 is movably assembled in the radial second displacement frame 27 through a radial first displacement guide column 28. The radial first displacement frame 29 is connected to a radial first loading component 10. The radial first loading component 10 drives the radial first displacement frame 29 to move along the second direction in the radial second displacement frame 27; the radial first displacement block 26 is assembled in the radial first displacement frame 29 through a radial second displacement guide column 31, and the radial first displacement block 26 is assembled in the radial first displacement frame 29 through a radial second displacement guide column 31. A displacement block 26 is connected to the radial second loading component 8, and the radial second loading component 8 drives the radial first displacement block 26 to move along the radial second displacement guide column 31 in the radial first displacement frame 29 along the first direction; the first direction and the second direction are perpendicular; one end of the simulated blade 7 is assembled in the radial first displacement block 26 and connected to the torque loading component, and the other end is connected to the slewing bearing 5, and is connected to the drive component, and is supported by the slewing bearing seat 4; the slewing bearing 5 is equipped with a collection component; a torque loading support 15 is set outside the torque loading component, one end of the torque loading support 15 is connected to the axial loading component 18 through the axial loading universal block 16, and the other end is connected to the simulated blade 7.

[0046] The simulated blade 7 and the slewing bearing 5 rotate under the drive of the driving component, and the torque loading component is connected to the simulated blade 7, so that the torque load is directly transmitted to the simulated blade 7, thereby realizing torque loading on the simulated blade 7; the radial first displacement frame 29 is connected to the radial first loading component 10, and the radial first loading component 10 drives the radial first displacement frame 29 to move along the second direction in the radial second displacement frame 27, and contacts the radial first displacement block 26, and transfers the load equally from the radial first displacement frame 29 to the radial first displacement block 26, and the radial first displacement block 26 transfers the load equally to the simulated blade 7, thereby realizing load application to the simulated blade 7 in the second direction; the radial first displacement block 26 is assembled in the radial first displacement frame 29 through the radial second displacement guide column 31, and the radial first displacement block 26 is connected to the radial second loading component 8, and the radial second loading component 8 drives the radial first displacement block 26 along the radial second displacement guide column 31 When moving along the first direction in the radial first displacement frame 29, the simulated blade 7 will be slightly deformed, and the load is equally transmitted to the simulated blade 7 by the radial first displacement block 26; the axial loading component 18 applies axial thrust to the torque loading support 15 through the axial loading universal block 16. Since the torque loading support 15 is connected to the simulated blade 7, the axial loading of the simulated blade 7 is realized, wherein the role of the axial loading universal block 16 is reflected in that when radial loading is performed, the torque loading support 15 will not affect the axial loading when moving radially with the simulated blade 7. The vibration signal, strain signal and sound signal of the slewing bearing 5 in different axial and radial directions and torque and other load processes are collected by the collection component and transmitted to the control system. Then, the control system calculates and analyzes the characteristic frequency through the fault analysis frequency formula and matches one or more main frequencies of the measured vibration signal, strain signal and sound signal, so as to obtain the specific fault position of the bearing.

[0047] In this embodiment, the second direction is a vertical direction in the radial direction of the simulated blade 7 , and the first direction is a horizontal direction in the radial direction.

[0048] In this embodiment, an axial loading bracket 19 for supporting the axial loading component 18 is provided on the basic platform 1. The control system consists of a control cabinet, related control hardware and software, etc. The control cabinet is designed to be floor-standing, and its operation panel includes a touch screen and buttons such as start, stop, and emergency stop for easy operation. The control system can control the speed, forward and reverse rotation of the drive component, as well as the loading of the radial first loading component 10, the radial second loading component 8, the torque loading component and the axial loading component 18 through the touch screen. In addition, the control system can also display parameters such as current, speed, torque, etc. in real time. In order to ensure the stability and reliability of the system, corresponding control hardware such as contactors, circuit breakers and PCBA boards are equipped.

[0049] Furthermore, the first radial displacement block 26 contacts the upper and lower inner ends of the first radial displacement frame 29 .

[0050] In this embodiment, the radial second displacement frame 27 is assembled in the support frame 9 through the axial displacement guide pillar 25 ; one end of the simulated blade 7 is assembled in the radial first displacement block 26 through the fixed bearing 30 .

[0051] Example 2

[0052] This embodiment further elaborates and illustrates the implementation of the present invention on the basis of Embodiment 1.

[0053] As an implementation method of this embodiment, the torque loading assembly includes a torque motor 14 and a planetary reducer I13. The torque motor 14 is connected to the planetary reducer I13. Through the deceleration mechanism, the load requirement on the torque motor 14 can be reduced, the torque motor 14 can be prevented from being overloaded and damaged, and the life of the torque motor 14 can be extended. The planetary reducer I13 is connected to the simulated blade 7 through the coupling 12 and the connecting rod 32, and the torque speed sensor 20 is assembled on the connecting rod 32.

[0054] During implementation, the torque motor 14 is started, and a torque load is applied to the simulated blade 7 through the planetary reducer I 13 , the coupling 12 and the connecting rod 32 .

[0055] As an example, the torque loading assembly uses a torque motor 14, which is connected to the simulated blade 7 via the coupling 12, the connecting rod 32. When the torque motor 14 is started, the torque motor 14 applies a torque load to the simulated blade 7 via the coupling 12 and the connecting rod 32.

[0056] As another implementation of this embodiment, the radial first loading assembly 10 adopts electric cylinder I; the radial second loading assembly 8 adopts electric cylinder II; and the axial loading assembly 18 adopts electric cylinder III.

[0057] In this embodiment, electric cylinder I, electric cylinder II and electric cylinder III are all electric cylinders in the prior art.

[0058] As an example, the radial first loading assembly 10 , the radial second loading assembly 8 , and the axial loading assembly 18 all employ cylinders.

[0059] Furthermore, the telescopic rod of the electric cylinder I is equipped with a tension and pressure sensor I11; the telescopic rod of the electric cylinder II is equipped with a tension and pressure sensor II21; the telescopic rod of the electric cylinder III is equipped with a tension and pressure sensor III17.

[0060] During implementation, a tension and pressure sensor I11 is installed on the telescopic rod of the electric cylinder I, and the electric cylinder I is started. The load is applied to the first radial displacement frame 29, and the electric cylinder I drives the first radial displacement frame 29 to move along the first radial displacement guide column 28 in the second direction within the second radial displacement frame 27 and contact the first radial displacement block 26, applying the same load to the first radial displacement block 26, and the first radial displacement block 26 transfers the same load to the simulated blade 7. During this loading process, the tension and pressure sensor I11 collects the load applied to the first radial displacement frame 2 9, thereby accurately detecting the load on the simulated blade 7 in the second direction; starting electric cylinder II, electric cylinder II drives the first radial displacement block 26 to move along the second radial displacement guide post 31 in the first direction within the first radial displacement frame 29, causing the simulated blade 7 to deform slightly, applying a load to the first radial displacement block 26, which is then equally transferred to the simulated blade 7. The load applied to the first radial displacement block 26 is collected by the tension and pressure sensor II 21, thereby accurately detecting the load on the simulated blade 7 in the first direction. Electric cylinder III applies axial thrust to the torque loading support 15 through the axial loading universal block 16. Because the torque loading support 15 is rigidly connected to the simulated blade 7, the axial thrust is equally transferred to the simulated blade 7 by the torque loading support 15, thereby achieving axial loading on the simulated blade 7. The axial thrust applied to the torque loading support 15 is collected by the tension and pressure sensor III 17 installed on the telescopic rod of electric cylinder III, thereby accurately detecting the axial load on the simulated blade 7.

[0061] As another implementation of this embodiment, the acquisition component includes a vibration signal acquisition component, a strain signal acquisition component and a sound acquisition component.

[0062] Furthermore, the vibration signal acquisition component includes a vibration sensor 22 and a 24-channel vibration collector; the strain signal acquisition component includes an optical fiber sensor 23 and a demodulator; and the sound acquisition component includes a sound sensor 24.

[0063] During implementation, the vibration signal is collected by the vibration sensor 22 and transmitted to the 24-channel vibration collector for sampling and then transmitted to the control system. The collector can ensure the accuracy of the vibration signal and realize the real-time transmission and real-time display of the vibration signal; the optical fiber sensor 23 collects the strain signal and transmits it to the demodulator for adjustment, adjusts the optical signal into an electrical signal, and samples the signal to obtain strain data for transmission to the control system; the sound sensor 24 captures the sound wave of the slewing bearing 5 during operation and transmits it to the control system after processing. The control system then calculates and analyzes the fault analysis frequency formula to obtain a match with one or more main frequencies of the measured vibration signal, strain signal and sound signal, and the specific fault location of the bearing can be obtained.

[0064] As an example, the vibration signal acquisition component can also adopt a vibration analyzer, which integrates functions such as signal acquisition, spectrum analysis, and fault diagnosis; the sound acquisition component includes a microphone array data acquisition instrument. The sound waves emitted by the slewing bearing 5 during operation are transmitted to the microphone array in the form of wave propagation. After the microphone captures the sound wave, it converts it into a corresponding electrical signal, which is input into the control system after passing through an amplifier, a filter and an A / D converter; the strain signal can also be collected through existing dynamic and static strain gauges.

[0065] As an example, Figure 5-Figure 6 As shown, Figure 5 This is the signal when the slewing bearing 5 is in a healthy state. Figure 6 is the fault signal of the inner ring raceway crack of the slewing bearing 5, curves 1-4 are vibration signals, curve 5 is the sound signal, and curves 6-11 are strain signals. In comparison, Figure 6 Medium signal amplitude ratio Figure 5 It is larger and contains a lot of impact signals. Therefore, when the slewing bearing 5 fails, the signal amplitude is larger.

[0066] As another implementation method of this embodiment, Figure 2-Figure 3 As shown, the drive assembly includes a drive motor 2 and a planetary reducer II 3. The drive motor 2 is connected to the planetary reducer II 3. Through the deceleration mechanism, the load requirement for the drive motor 2 can be reduced, the drive motor 2 can be prevented from being overloaded and damaged, and the service life of the drive motor 2 can be extended. The planetary reducer II 3 drives the simulated blade 7 to rotate by cooperating with the gear in the slewing bearing 5 through the drive pinion 6.

[0067] As an example, the drive assembly may only use the drive motor 2 .

[0068] Example 4

[0069] This embodiment further elaborates and supplements the implementation manner of the present invention on the basis of Embodiment 1, Embodiment 2 or Embodiment 3.

[0070] A wind turbine pitch bearing fault simulation experiment monitoring method includes the following steps:

[0071] Step 1: Start the experimental platform to perform torque loading, axial loading, radial horizontal loading, and vertical loading on the simulated blade 7;

[0072] Step 2: collecting the vibration signal, strain signal, and sound signal of the slewing bearing 5 during the loading process in step 1 through the acquisition component, and transmitting the collected signals to the control system to obtain the main frequencies of the measured vibration signal, strain signal, and sound signal;

[0073] Step 3: Calculate the characteristic frequency using the fault characteristic frequency formula. The fault characteristic frequency formula is as follows:

[0074] Outer race fault characteristic frequency:

[0075] ;

[0076] Inner race fault characteristic frequency:

[0077] ;

[0078] Rolling element failure characteristic frequency:

[0079] ;

[0080] Cage failure characteristic frequency:

[0081] ;

[0082] in is the number of rolling elements, is the rolling element diameter, is the raceway pitch diameter, is the bearing contact angle, Indicates frequency conversion;

[0083] Step 4: If the characteristic frequency obtained in step 3 matches one or more main frequencies in the signal measured in step 2, the fault location can be obtained.

Claims

1. A wind turbine pitch bearing fault simulation experimental platform, characterized by: The invention comprises a simulated blade (7), a control system, and a basic platform (1). The basic platform (1) is provided with a support frame (9), a radial second displacement frame (27) is assembled in the support frame (9), a radial first displacement frame (29) is movably assembled in the radial second displacement frame (27) through a radial first displacement guide column (28), the radial first displacement frame (29) is connected to a radial first loading component (10), and the radial first loading component (10) drives the radial first displacement frame (29) to move along the second direction in the radial second displacement frame (27); a radial first displacement block (26) is assembled in the radial first displacement frame (29) through a radial second displacement guide column (31), and the radial first displacement block (26) is connected to the radial first displacement frame (29). The first radial displacement block (26) is connected to the second loading assembly (8), and the first radial displacement block (26) is driven by the second radial loading assembly (8) to move along the first radial displacement guide column (31) in the first radial displacement frame (29); the first direction and the second direction are perpendicular; one end of the simulated blade (7) is assembled in the first radial displacement block (26) and connected to the torque loading assembly, and the other end is connected to the slewing bearing (5), and is connected to the driving assembly and supported by the slewing bearing seat (4); the slewing bearing (5) is equipped with a collection assembly; a torque loading support (15) is provided outside the torque loading assembly, one end of the torque loading support (15) is connected to the axial loading assembly (18) through the axial loading universal block (16), and the other end is connected to the simulated blade (7); The radial first displacement block (26) contacts the upper and lower ends of the radial first displacement frame (29); The radial second displacement frame (27) is assembled in the support frame (9) via the axial displacement guide column (25); one end of the simulated blade (7) is assembled in the radial first displacement block (26) via the fixed bearing (30); The torque loading assembly includes a torque motor (14) and a planetary reducer I (13), the torque motor (14) is connected to the planetary reducer I (13), the planetary reducer I (13) is connected to the simulated blade (7) through a coupling (12) and a connecting rod (32), and a torque speed sensor (20) is assembled on the connecting rod (32); The acquisition component includes a vibration signal acquisition component, a strain signal acquisition component and a sound acquisition component.

2. A wind turbine pitch bearing fault simulation experimental platform according to claim 1, characterized in that: The radial first loading assembly (10) adopts electric cylinder I; the radial second loading assembly (8) adopts electric cylinder II; and the axial loading assembly (18) adopts electric cylinder III.

3. A wind turbine pitch bearing fault simulation experimental platform according to claim 2, characterized in that: The telescopic rod of the electric cylinder I is equipped with a tension and pressure sensor I (11); the telescopic rod of the electric cylinder II is equipped with a tension and pressure sensor II (21); the telescopic rod of the electric cylinder III is equipped with a tension and pressure sensor III (17).

4. A wind turbine pitch bearing fault simulation experimental platform according to claim 1, characterized in that: The vibration signal acquisition component includes a vibration sensor (22) and a 24-channel vibration acquisition instrument; the strain signal acquisition component includes an optical fiber sensor (23) and a demodulator; and the sound acquisition component includes a sound sensor (24).

5. The wind turbine pitch bearing fault simulation experimental platform according to claim 1, characterized in that: The driving assembly includes a driving motor (2) and a planetary reducer II (3). The driving motor (2) is connected to the planetary reducer II (3). The planetary reducer II (3) drives the driving pinion (6) and the gear in the slewing bearing (5) to rotate with the simulated blade (7).

6. A wind turbine pitch bearing fault simulation experiment monitoring method, performed by the experimental platform according to any one of claims 1 to 5, characterized in that: The steps include: Step 1: Start the experimental platform to perform torque loading, axial loading, radial horizontal loading, and vertical loading on the simulated blade (7); Step 2: collecting the vibration signal, strain signal and sound signal of the slewing bearing (5) during the loading process in step 1 through the acquisition component, and transmitting them to the control system to obtain the main frequency of the measured vibration signal, strain signal and sound signal; Step 3: Calculate the characteristic frequency using the fault characteristic frequency formula. The fault characteristic frequency formula is as follows: Outer race fault characteristic frequency: ； Inner ring Fault characteristic frequency: ； Rolling element failure characteristic frequency: ； Cage failure characteristic frequency: ； in is the number of rolling elements, is the rolling element diameter, is the raceway pitch diameter, is the bearing contact angle, Indicates frequency conversion; Step 4: If the characteristic frequency obtained in step 3 matches one or more main frequencies in the signal measured in step 2, the fault location can be obtained.

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