A ball joint fault online detection device and method

Abstract

A device and method for online detection of ball joint faults relate to the field of real-time detection of moving component faults. It solves the existing problem of indirectly judging the state of a ball joint by manual observation or detecting the preload with a torque wrench, which has a high false detection rate and requires the equipment to stop running. The device includes: a ball joint, an actuator, the ball joint includes a flange, a bearing socket, a bearing, a hinge support, and a first sensor. The flange is connected to the actuator through a bolt at the upper part and is connected to the bearing socket at the lower part. A first sensor is provided on the bearing socket. The first sensor is used to collect the position information of the actuator and send the position information to a control computer. The two ends of the bearing are supported at the two ends of the hinge support, and the hinge support is used to fix the bearing on the platform. The method is implemented based on the device and is also applicable to the connection parts between the actuator and the foundation, and between the actuator and the motion platform in heavy hydraulic motion equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of real-time detection of motion component faults, and in particular to an online detection device and method for ball joint faults. Background Art

[0002] As a connecting device, a ball joint is a component connected to a force control circuit. It is used when bending compensation is required or when two components are out of alignment. Ball joints allow for seamless use, have very low friction, and a long service life. They are primarily used in the connection between the actuator and foundation, and between the actuator and the motion platform, of heavy-duty hydraulic motion equipment. Ball joints are installed at the front and rear ends of the servo actuator to ensure directional tracking in the loading direction, protect the actuator from lateral forces, and extend its life. They primarily transmit force and are a key component, adjusting the angle between the actuator and foundation, and between the actuator and the motion platform, in real time according to the needs of the equipment.

[0003] During installation, and especially during use, ball joints often experience sudden performance changes or even failure. This is primarily due to displacement of internal components or fastening bolts, which can alter the joint's condition. Due to the heavy weight, high load-bearing capacity, and rigid structure of these components, internal testing devices are often not feasible. Current technology primarily relies on manual observation, either by stopping the equipment and observing it, or indirectly testing the preload using a torque wrench.

[0004] However, conventional methods have a high false detection rate and require the equipment to stop operating. In particular, some equipment is in poor working condition. If not discovered in time, it may cause damage to the ball joint or even platform collapse. Therefore, an effective detection method is needed to realize the real-time status detection function of the ball joint. Summary of the Invention

[0005] The present invention aims to solve the problem that the existing technology mainly relies on manual observation, which is to stop the equipment and observe manually or use a torque wrench to detect the preload force to indirectly determine the state of the ball joint, resulting in a high false detection rate and the need to stop the equipment. In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0006] Solution 1: The present invention proposes an online detection device for ball joint faults, the device comprising:

[0007] Ball joint, actuator, the ball joint includes a flange, a bearing socket, a bearing, a hinge support, and a first sensor. The upper part of the flange is connected to the actuator through bolts, and the lower part is connected to the bearing socket. The actuator is provided with a first sensor, which is used to collect the position information of the actuator and send the position information to the control computer. The two ends of the bearing are supported at the two ends of the hinge support, and the hinge support is used to fix the bearing on the platform.

[0008] Furthermore, a preferred embodiment is provided, wherein the rotation angle between the bearing socket and the bearing is ±30°, and the swing angle is ±10°.

[0009] Furthermore, a preferred embodiment is provided, wherein the device further comprises a wedge block, and the wedge block is used to adjust the preload force of the ball joint.

[0010] Furthermore, a preferred embodiment is provided, in which the pre-tightening force of the ball joint is adjusted based on the wedge block and the position is locked by the pre-tightening bolt.

[0011] Furthermore, a preferred embodiment is provided, in which a second sensor is provided on one side of the flange for collecting acceleration information of the flange and sending the information to the AD acquisition module.

[0012] Furthermore, a preferred embodiment is provided, in which a third sensor is provided on one side of the bearing socket for collecting acceleration information of the bearing socket and sending the information to the AD acquisition module.

[0013] Furthermore, a preferred embodiment is provided, in which a fourth sensor is provided on the inner side of the bearing for collecting bearing acceleration information and sending the information to the AD acquisition module.

[0014] Furthermore, a preferred embodiment is provided, in which a fifth sensor is provided on one side of the hinge support for collecting acceleration information of the hinge support and sending the information to the AD acquisition module.

[0015] Solution 2: A method for online detection of ball joint faults, characterized in that the method is implemented based on the device described in Implementation 1, and the method includes:

[0016] Assume that the input and output of the sensor are u(t) and v(t), and the noise at the input and output are a(t) and b(t).

[0017] Assume that the input and output noises are uncorrelated and uncorrelated with the signal, that is,

[0018] G ua (f) = G vb (f) = G ab (f)=0 (1)

[0019] Where G ua (f) represents the cross-spectral power spectrum between the input signal u(t) and the input noise a(t); G vb (f) represents the cross-spectral power spectrum between the output signal v(t) and the output noise b(t); G ab (f) represents the cross-spectral power spectrum between the input noise a(t) and the output noise b(t);

[0020] G(f) represents the calculation of the signal power spectrum, because G aa (f)≥0, G bb (f)≥0, then

[0021]

[0022] Where G uu (f) represents the autospectral power spectrum of the input signal u(t); G vv (f) represents the autospectral power spectrum of the output signal v(t); G aa (f) represents the autospectral power spectrum of the input signal noise a(t); G bb (f) represents the autospectral power spectrum of the output signal noise b(t); G ry (f) represents the cross-spectral power spectrum of the noisy input signal r(t) and the noisy output signal y(t); G rr (f) represents the autospectral power spectrum of the input signal r(t) containing noise; G yy (f) represents the autospectral power spectrum of the output signal y(t) containing noise;

[0023] That is, the relationship between the input and output signals of any component of the ball joint is

[0024] Y(f)-b(f)=H(f)(X(f)-a(f)) (3)

[0025] Where Y(f) is the frequency domain signal of y(t), b(f) is the frequency domain signal of b(t), R(f) is the frequency domain signal of r(t), and a(f) is the frequency domain signal of a(t);

[0026] Then the ideal input and output in this relatively noise-free state, the error is

[0027] E(f)=H(f)a(f)-b(f) (4)

[0028] Substitute equations (1), (2), and (3) into equation (4), and take the expected spectrum matrix [E(f)]

[0029]

[0030] Based on the spectrum matrix [E(f)], the input-output characteristic K(f) of the spherical joint fault is solved.

[0031] Furthermore, a preferred embodiment is provided, wherein the calculation method for solving the input-output characteristic K(f) of the ball joint fault is:

[0032]

[0033] The present invention is beneficial in that:

[0034] The device and method for online detection of ball joint faults described in the present invention solve the problem in the prior art that the working status of the ball joint cannot be detected in real time. The device and method are simple and effective, and the method is universal and can be expanded to other components with reference to the working environment.

[0035] The device for online ball joint fault detection described in this invention primarily comprises heavy-duty hydraulic motion equipment. The ball joints are installed at the front and rear ends of the servo actuator, ensuring directional tracking in the loading direction and protecting the actuator from lateral forces, thereby extending its lifespan. They primarily transmit force and, as a key component, adjust the angles between the actuator and the foundation, as well as between the actuator and the motion platform, in real time, according to the equipment's needs.

[0036] The present invention is also applicable to connecting rotating components and positioning devices, such as vibrators, connectors, and joints. In the aviation field, ball joints are also used to control aircraft wings and tail planes, as well as to adjust fuselage joints. Furthermore, ball joints can be used to connect and control architectural structures, such as steel structures in overpasses and large buildings.

[0037] The present invention is also mainly applied to the connection parts between the actuator and the foundation, and between the actuator and the motion platform in heavy hydraulic motion equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A diagram of a large-scale test equipment for installing a ball joint as described in embodiment eleven.

[0039] Figure 2 This is an external structural diagram of the ball joint described in embodiment eleven.

[0040] Figure 3 This is a diagram of the internal structure of the ball joint described in embodiment eleven.

[0041] Figure 4 This is an input-output characteristic diagram of a certain component of the ball joint described in embodiment eleven.

[0042] Figure 5 This is an observation curve diagram of the ball joint characteristics used in a certain type of equipment described in embodiment eleven.

[0043] Figure 6 This is an electrical schematic diagram of the AD acquisition module described in the eleventh embodiment.

[0044] In the figure, upper ball joint 1, lower ball joint 2, first sensor 3, flange 4, ball joint flange 4-1, sensor piston flange 4-2, bearing socket 5, bearing 6, hinge support 7, wedge 8, pre-tightening bolt 9, platform 10, actuator 11. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the implementation methods of this application clearer, the technical solutions in the implementation methods of this application will be clearly and completely described below in combination with the drawings in the implementation methods of this application. Obviously, the described implementation methods are only part of the implementation methods of this application, not all of the implementation methods.

[0046] Embodiment 1. This embodiment provides an online detection device for ball joint faults, which includes: a ball joint, which includes a flange 4, a bearing socket 5, a bearing 6, a hinge support 7, and a first sensor 3. The flange 4 is connected to the actuator 11 at the upper part through bolts, and is connected to the bearing socket 5 at the lower part. The actuator 11 is provided with a first sensor 3, which is used to collect position information of the actuator 11 and send the position information to the control computer. The two ends of the bearing 6 are supported on the two ends of the hinge support 7, and the hinge support 7 is used to fix the bearing on the platform 10.

[0047] The flange 4 described in this embodiment can be used as the installation position of the sensor, and can also be installed at any position of the flange. Similarly, the other sensors described in this embodiment are installed in the same way as the flange 4, and it is only necessary to ensure that the sensitive axes of all sensors are consistent.

[0048] Embodiment 2: This embodiment further limits the ball joint fault online detection device described in Embodiment 1. The rotation angle between the bearing socket 5 and the bearing 6 is ±30°, and the swing angle is ±10°.

[0049] Embodiment 3: This embodiment further limits the device for online detection of ball joint faults described in embodiment 2. The device further includes a wedge block 8, which is used to adjust the preload force of the ball joint.

[0050] Embodiment 4: This embodiment further limits the online detection device for ball joint faults described in Embodiment 3, and adjusts the pre-tightening force of the ball joint based on the wedge block 8 and locks the position through the pre-tightening bolt 9.

[0051] Implementation method 5: This implementation method further limits the online detection device for ball joint faults described in implementation method 2. A second sensor is provided on one side of the flange for collecting acceleration information of the flange and sending it to the AD acquisition module.

[0052] Implementation method 6: This implementation method further limits the ball joint fault online detection device described in implementation method 2. A third sensor is provided on one side of the bearing socket for collecting acceleration information of the bearing socket and sending it to the AD acquisition module.

[0053] Implementation method 7: This implementation method further limits the ball joint fault online detection device described in implementation method 2. A fourth sensor is provided on the inner side of the bearing for collecting bearing acceleration information and sending it to the AD acquisition module.

[0054] Implementation 8. This implementation further limits the device for online detection of ball joint faults described in Implementation 4. A fifth sensor is provided on one side of the hinge support for collecting acceleration information of the hinge support and sending it to the AD acquisition module.

[0055] Embodiment 9: This embodiment proposes a method for online detection of ball joint faults. The method is implemented based on the device described in embodiment 1, and the method includes:

[0056] Assume that the input and output of the sensor are u(t) and v(t), and the noise at the input and output are a(t) and b(t).

[0057] Assume that the input and output noises are uncorrelated and uncorrelated with the signal, that is,

[0058] G ua (f) = G vb (f) = G ab (f)=0 (1)

[0059] Where G ua (f) represents the cross-spectral power spectrum between the input signal u(t) and the input noise a(t); G vb (f) represents the cross-spectral power spectrum between the output signal v(t) and the output noise b(t); G ab (f) represents the cross-spectral power spectrum between the input noise a(t) and the output noise b(t);

[0060] G(f) represents the calculation of the signal power spectrum, because G aa (f)≥0, G bb (f)≥0, then

[0061]

[0062] Where G uu (f) represents the autospectral power spectrum of the input signal u(t); G vv (f) represents the autospectral power spectrum of the output signal v(t); G aa (f) represents the autospectral power spectrum of the input signal noise a(t); G bb (f) represents the autospectral power spectrum of the output signal noise b(t); G ry (f) represents the cross-spectral power spectrum of the noisy input signal r(t) and the noisy output signal y(t); G rr(f) represents the autospectral power spectrum of the input signal r(t) containing noise; G yy (f) represents the autospectral power spectrum of the output signal y(t) containing noise;

[0063] That is, the relationship between the input and output signals of any component of the ball joint is

[0064] Y(f)-b(f)=H(f)(X(f)-a(f)) (3)

[0065] Where Y(f) is the frequency domain signal of y(t), b(f) is the frequency domain signal of b(t), R(f) is the frequency domain signal of r(t), and a(f) is the frequency domain signal of a(t);

[0066] Then the ideal input and output in this relatively noise-free state, the error is

[0067] E(f)=H(f)a(f)-b(f) (4)

[0068] Substitute equations (1), (2), and (3) into equation (4), and take the expected spectrum matrix [E(f)]

[0069]

[0070] Based on the spectrum matrix [E(f)], the input-output characteristic K(f) of the spherical joint fault is solved.

[0071] Embodiment 10: This embodiment further limits the online detection method for ball joint faults described in embodiment 9. The calculation method for solving the input-output characteristic K(f) of the ball joint fault is:

[0072]

[0073] Implementation 11: This implementation provides an example, which is used to explain the above implementations 1 to 8. Specifically, the example is as follows:

[0074] See also Figures 1 to 6 The ball joint described in this embodiment is mainly used for large-scale test equipment, and the equipment and its load are relatively heavy, such as Figure 1 As shown in the figure, the device connects the motion platform via a ball joint and actuator. This ball joint is called the upper ball joint. The actuator is fixed to the reaction base via a ball joint and actuator. This ball joint is called the lower ball joint. As can be seen, the ball joint bears large loads during device movement and requires a certain degree of joint swing.

[0075] like Figure 2 As shown in the figure, the ball joint consists of the following parts: flange, bearing socket, bearing, and bearing seat. The flange is connected to the sensor in the actuator through the upper part of the bolt. Figure 1 The lower part is connected to the bearing socket, which is mainly used as a connecting part between an actuator and a hinge. The bearing socket and the bearing undergo low friction movement, requiring a certain relative movement between them. Generally, the rotation angle is ±30° and the swing angle is ±10°. Figure 3 The specific angle depends on the type of ball joint, specifically the amount of force it can withstand. During initial installation, wedge 8 is used to adjust the clearance in the bearing socket, and preload bolts 9 are then used to adjust the friction between the socket and the bearing. The bearing is mounted on a hinge support, which is connected to the ball joint on the motion platform or to the ball joint under the foundation. When the motion platform is in motion, loose bolts or bearing wear in the flange, preload bolts 9, or bearing seat are very likely to occur, affecting the performance of the entire motion platform.

[0076] Based on the spherical joint structure and motion relationship, a real-time observation method is used to perform performance testing. Figure 2 The positions of several key components are monitored by external acceleration sensors, and the performance of each kinematic pair is judged by the observation values ​​of several acceleration sensors.

[0077] Since both the upper and lower ball joints transmit the characteristics of the actuator, it can be considered that the output of the actuator tail enters the ball joint completely without noise. The acceleration sensor used for collection has noise, so the output is considered to have noise. Figure 4 The figure shows the mechanism diagram for detecting a spherical joint. The input and output are u(t) and v(t), respectively. The noise at the input and output are a(t) and b(t), respectively. a(t) does not enter the spherical joint, while b(t) enters the acceleration acquisition.

[0078] Assume that the input and output noises are uncorrelated and uncorrelated with the signal, that is,

[0079] G ua (f) = G vb (f) = G ab (f)=0 (1)

[0080] Here, G(f) represents the calculation of the signal power spectrum, and the same applies below.

[0081] Because G aa (f)≥0, G bb (f)≥0, then

[0082]

[0083] Therefore, the relationship between the input and output signals of any component of the ball joint is:

[0084] Y(f)-b(f)=H(f)(X(f)-a(f)) (3)

[0085] Then the ideal input and output in this relatively noise-free state, the error is

[0086] E(f)=H(f)a(f)-b(f) (4)

[0087] Substitute equations (1), (2), and (3) into equation (4), and take the expected spectrum matrix [E(f)]

[0088]

[0089] To optimize the input-output characteristics of the reaction spherical joint, the sum of the diagonal elements of the spectrum matrix [E(f)] must be minimized. According to matrix analysis theory, the optimal input-output characteristic is the eigenvector corresponding to the minimum eigenvalue of [E(f)]. For each spherical joint, each component is a single-input single-output system. Since only output noise is considered here, the eigenvector, i.e., the input-output characteristic K(f), is

[0090]

[0091] Accelerometers are used to collect data from several key components of a ball joint, which are then graphically displayed in real time. Furthermore, error thresholds can be used to determine the differences between characteristic curves, allowing the program to automatically determine the differences. By specifying each component as input and the others as output, the characteristics of all components can be obtained through traversal and solution, allowing the program to automatically classify fault types and identify fault points.

[0092] exist Figure 1 、 Figure 2 Five acceleration sensors are placed at the corresponding positions. Figure 5 The upper spherical joint characteristic curves for three actuators are shown, plotting the characteristic curves between sensor piston flange 4-2 and spherical joint flange 4-1, spherical joint flange 4-1 and bearing socket 5, bearing socket 5 and bearing 6, and bearing 6 and bearing seat 7. It can be seen that within the specified bandwidth, the characteristics of bearing socket 5 and bearing 6 in the upper hinge of actuator 11 have deteriorated, possibly indicating loosening of preload bolt 9.

[0093] Similarly, a characteristic curve can be made with the sensor piston flange as input and other components as output to further refine the fault type and fault point.

[0094] See also Figure 6 As shown, Figure 6 The AD acquisition module collects information from sensor 1 via computer analog acquisition board LC2-1 and transmits it via port P1 on analog conditioning board AG2. 24V power is provided by pin 3 of the port, and the force signal is collected via pin 6 of the port. Other sensors can be collected sequentially via ports P2 through P5.

[0095] Those skilled in the art will understand that the above description is only a preferred embodiment of the present invention, and the features described in the various embodiments and / or claims of the present disclosure may be combined or coupled in various ways, even if such a combination or coupling is not explicitly described in the present disclosure. It is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art may still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

[0096] Although preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such changes and modifications as fall within the scope of the claims and their equivalents.

Claims

1. A method for online detection of ball joint faults, characterized in that: The method is implemented based on a ball joint fault online detection device, the ball joint fault online detection device comprising: a ball joint, an actuator (11), the ball joint comprising a flange (4), a bearing socket (5), a bearing (6), a hinge support (7), and a first sensor (3), the flange (4) being connected to the actuator (11) at the upper portion through a bolt, and being connected to the bearing socket (5) at the lower portion, the actuator (11) being provided with a first sensor (3), the first sensor being used to collect position information of the actuator (11) and to send the position information to a control computer, the two ends of the bearing (6) being supported at the two ends of the hinge support (7), and the hinge support (7) being used to fix the bearing on the platform (10); The ball joint fault online detection method comprises: Set the sensor input and output to u ( t )and v ( t ), the noise at the input and output are a ( t )and b ( t ); Assume that the input and output noises are uncorrelated and uncorrelated with the signal, that is, (1) Where, represents the input signal u(t) and input noise a (t) cross-spectral power spectrum; represents the cross-spectral power spectrum between the output signal v(t) and the output noise b(t); represents input noise a The cross-spectral power spectrum between (t) and the output noise b(t); G(f) represents the calculation of the signal power spectrum, because , , then (2) Where, represents the autospectral power spectrum of the input signal u(t); represents the autospectral power spectrum of the output signal v(t); Indicates the input signal noise a The autospectral power spectrum of (t); represents the autospectral power spectrum of the output signal noise b(t); represents the cross-spectral power spectrum of the noisy input signal r(t) and the noisy output signal y(t); represents the autospectral power spectrum of the input signal r(t) containing noise; represents the autospectral power spectrum of the output signal y(t) containing noise; That is, the relationship between the input and output signals of any component of the ball joint is (3) Where Y(f) is y ( t ) frequency domain signal, b(f) is b( t ) frequency domain signal, R(f) is r( t ) frequency domain signal, a (f) a ( t )’s frequency domain signal; Then the ideal input and output in this relatively noise-free state, the error is (4) Substitute equations (1), (2), and (3) into equation (4), and take the expected spectrum matrix (5) Based on the spectral matrix , solve the input-output characteristic K(f) of the ball joint fault; A second sensor is provided on one side of the flange for collecting acceleration information of the flange and sending it to the AD acquisition module; A third sensor is provided on one side of the bearing socket, for collecting acceleration information of the bearing socket and sending it to the AD acquisition module; A fourth sensor is provided inside the bearing for collecting bearing acceleration information and sending it to the AD acquisition module; A fifth sensor is provided on one side of the hinge support for collecting acceleration information of the hinge support and sending it to the AD acquisition module.

2. The ball joint fault online detection method according to claim 1, characterized in that: The rotation angle between the bearing socket (5) and the bearing (6) is , swing angle .

3. The ball joint fault online detection method according to claim 1, characterized in that: The device further comprises a wedge (8), wherein the wedge (8) is used to adjust the preload force of the ball joint.

4. The method for online detection of ball joint faults according to claim 3, characterized in that: The preload force of the ball joint is adjusted based on the wedge (8) and the position is locked by the preload bolt (9).

5. The online detection method for ball joint faults according to claim 1, characterized in that: The calculation method for solving the input-output characteristic K(f) of the ball joint fault is: (6)。

Images