Elastic member natural frequency detection system and method

Abstract

The application provides a kind of elastic component inherent frequency detection system and method, the detection system includes base, for placing the elastic component to be measured;Support, for fixing the knocking mechanism;Electromagnetic excitation mechanism, for generating excitation force according to the target current received;Knocking mechanism, magnetic element is provided in the knocking mechanism, for knocking the elastic component to be measured according to excitation force;Force sensing element, for detecting the real-time knocking force of knocking mechanism;Vibration sensing element, for detecting the vibration response of the elastic component to be measured;Controller, for calculating the target current according to the target knocking force received for controlling the knocking mechanism, and the knocking mechanism is controlled away from the elastic component to be measured according to real-time knocking force and target knocking force, and the inherent frequency of the elastic component to be measured is calculated according to vibration response.The application, realize automatic knocking excitation, the angle, strength and position of knocking are controllable, high accuracy, high efficiency.

Description

Technical Field

[0001] This invention relates to the field of detection technology, and in particular to a system and method for detecting the natural frequency of an elastic component. Background Technology

[0002] A dynamic vibration absorber is a device that uses a resonant system to absorb the vibrational energy of an object in order to reduce its vibration. Dynamic vibration absorbers are crucial components for controlling the noise, vibration, and harshness (NVH) performance of vehicles. To meet vehicle NVH performance requirements, a natural frequency test is necessary before a dynamic vibration absorber is put into use.

[0003] Currently, the existing method for detecting the natural frequency of dynamic vibration absorbers involves manually striking the absorber with a handheld experimental hammer. The hammer is equipped with a force sensor and an accelerometer. The force sensor collects the striking force, and when the force meets the requirements (needing to be controlled between 5 and 7 N), the accelerometer collects the vibration response of the absorber, thus calculating its natural frequency. However, since dynamic vibration absorbers are mainly composed of rubber and exhibit significant nonlinearity, the existing striking excitation method is prone to deviations in striking angle, force, and position. This requires multiple (at least 7) ​​handheld excitations with the experimental hammer, followed by averaging the results, which is time-consuming and inefficient. Furthermore, since the force of each strike needs to be controlled between 5 and 7 N, it is difficult to manually control the force. The magnitude of the striking force also depends on the angle and position of the striking surface. During the test, it is difficult to simultaneously ensure consistency in angle, force, and position across multiple measurements, leading to many ineffective strikes with large errors and fluctuations, further wasting time. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing detection methods, such as low accuracy, long time consumption, and low efficiency, and to provide a system and method for detecting the natural frequency of elastic components.

[0005] The present invention provides a system for detecting the natural frequency of an elastic component, comprising a base, a bracket, an electromagnetic excitation mechanism, a striking mechanism, a force sensing element, a vibration sensing element, and a controller.

[0006] The base is used to hold the elastic component to be tested.

[0007] A bracket, mounted on the base, is used to fix the electromagnetic vibration mechanism and the striking mechanism;

[0008] An electromagnetic excitation mechanism is mounted on the support and is communicatively connected to the controller to generate excitation force according to the received target current.

[0009] A striking mechanism is mounted on the bracket and connected to the electromagnetic vibration mechanism. The striking mechanism contains a magnetic element for striking the elastic component under test according to the excitation force.

[0010] A force sensing element is disposed on the striking mechanism. The force sensing element is communicatively connected to the controller and is used to detect the real-time striking force of the striking mechanism.

[0011] A vibration sensing element is disposed on the elastic component under test and is used to detect the vibration response of the elastic component under test;

[0012] The controller is configured to calculate the target current based on the target striking force received for controlling the striking mechanism, control the striking mechanism away from the elastic component under test based on the real-time striking force and the target striking force, and calculate the natural frequency of the elastic component under test based on the vibration response.

[0013] Furthermore, the electromagnetic excitation mechanism includes a first electromagnetic coil, and the striking mechanism includes a housing with a hollow cavity, on which the first electromagnetic coil is wound. The first electromagnetic coil can be connected and disconnected from the power supply. A hammer body is provided inside the housing, and the magnetic element is provided inside the hammer body. A hammer head is provided at one end of the hammer body, and the force sensing element is provided on the hammer head.

[0014] Furthermore, the power supply includes a first power supply component and a second power supply component, and the first electromagnetic coil is capable of being switched on and off with the first power supply component.

[0015] The striking mechanism further includes a hammer fixing assembly, which includes a sliding block, an iron core, an elastic component, and a second electromagnetic coil. The sliding block and the iron core are disposed at the other end of the hammer body. The iron core is connected to the sliding block through the elastic component. The iron core is provided with the second electromagnetic coil, which can be connected and disconnected from the second power supply assembly.

[0016] The controller is also used for:

[0017] When the first electromagnetic coil is about to be connected to or has been connected to the first power supply component with a first direction current, the second electromagnetic coil is controlled to be energized or disconnected from the second power supply component or the current direction is changed so that the sliding block can move relative to the housing. The first current direction is the current direction that can drive the striking mechanism toward the elastic component to be tested.

[0018] When the striking mechanism moves away from the elastic component under test, or when the striking mechanism moves away from the elastic component under test for a certain period of time or a certain distance, the second electromagnetic coil is controlled to disconnect or connect with the second power supply component or change the direction of the current so that the sliding block can move and be fixed relative to the housing.

[0019] Second power supply component

[0020] Furthermore,

[0021] The detection system further includes a switching unit, which includes a first electrical connection point and a second electrical connection point. The first electrical connection point is used to connect to a power source, and the first electrical connection point and the second electrical connection point can be connected and disconnected.

[0022] The striking mechanism further includes a hammer fixing assembly, which includes a sliding block, an iron core, an elastic component, and a second electromagnetic coil. The sliding block and the iron core are disposed at the other end of the hammer body. The iron core is connected to the sliding block through the elastic component, and the iron core is provided with the second electromagnetic coil.

[0023] One end of the first electromagnetic coil is connected to one end of the second electromagnetic coil, the other end of the first electromagnetic coil is connected to the power source, and the other end of the second electromagnetic coil is connected to the second electrical connection point. By controlling the first electrical connection point and the second electrical connection point to be connected and disconnected, the connection and disconnection between the first electromagnetic coil and the power source can be realized.

[0024] When the first electrical connection point and the second electrical connection point are switched on and off, the elastic state of the elastic component will change. As the elastic state of the elastic component changes, the sliding block can slide in the hollow cavity or be fixed to the inner wall of the hollow cavity.

[0025] Furthermore, the switching unit also includes a third electrical connection point, and the other end of the first electromagnetic coil is used for connecting the third electrical connection point and the power supply. When the first electrical connection point is connected to the second electrical connection point, the second electrical connection point is disconnected from the third electrical connection point. When the second electrical connection point is connected to the third electrical connection point, the first electrical connection point is disconnected from the second electrical connection point.

[0026] Furthermore, the detection system also includes a position sensing element, which is used to detect the position of the force sensing element. When the force sensing element is not detected or the position of the force sensing element exceeds a preset value or a preset range, the system controls the first electrical contact and the second electrical contact of the switching unit to disconnect or the second electrical contact and the third electrical contact to connect.

[0027] Furthermore, the detection system also includes a telescopic mechanism, one end of which is connected to the base and the other end of which is connected to the bracket. The bracket moves along the vertical direction of the base via the telescopic mechanism.

[0028] Furthermore, the detection system also includes a rotating mechanism, one end of which is connected to the base and the other end of which is connected to the bracket. The bracket rotates along the vertical direction around the base via the rotating mechanism.

[0029] The technical solution of the present invention also provides a detection method for the elastic component natural frequency detection system as described above, comprising:

[0030] Receives a target striking force for controlling the striking mechanism;

[0031] Calculate the target current used to control the electromagnetic excitation mechanism to generate excitation force based on the target impact force;

[0032] The real-time striking force of the striking mechanism is acquired in real time, and the striking mechanism is controlled to move away from the elastic component under test based on the real-time striking force and the target striking force.

[0033] The vibration response of the elastic component under test is received, and the natural frequency of the elastic component under test is calculated based on the vibration response.

[0034] Furthermore, the step of calculating the target current for controlling the electromagnetic excitation mechanism to generate excitation force based on the target impact force includes:

[0035] The target current is calculated using the following formula:

[0036]

[0037] Wherein, H is the magnetic field strength of the magnetic element; N is the number of turns of the second electromagnetic coil; I is the target current; Le is the effective magnetic circuit length; m is the mass of the magnetic element; x is the specific magnetization coefficient of the magnetic element; v is the volume of the magnetic element; and gradH is the magnetic field gradient.

[0038] The above technical solution has the following beneficial effects: By setting up a base, bracket, electromagnetic excitation mechanism, striking mechanism, fixing mechanism, force sensing element, vibration sensing element, and controller, during testing, the elastic component to be tested is placed on the base. The controller calculates the target current required for the electromagnetic excitation mechanism to generate the excitation force based on the received target striking force. The striking mechanism strikes the elastic component to be tested according to the excitation force, and the real-time striking force of the striking mechanism is detected in real time. If the real-time striking force is consistent with the target striking force, the striking mechanism is controlled to move away from the elastic component to be tested, and the vibration response of the elastic component to be tested is detected by the vibration sensing element. The natural frequency of the elastic component to be tested is calculated based on the vibration response, realizing automatic striking excitation. The striking angle, force, and position are controllable, with high accuracy, no need for multiple manual operations, and high efficiency. Attached Figure Description

[0039] The disclosure of this invention will become more readily understood by referring to the accompanying drawings. It should be understood that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings:

[0040] Figure 1 This is a schematic diagram of the structure of an elastic component natural frequency detection system according to an embodiment of the present invention;

[0041] Figure 2 yes Figure 1 AA magnified image;

[0042] Figure 3 This is a flowchart of the detection method of an elastic component natural frequency detection system provided in an embodiment of the present invention.

[0043] Appendix Label Reference Table:

[0044] 10-Base; 11-Bracket; 111-First distance sensing element; 20-First electromagnetic coil; 30-Striking mechanism; 31-Force sensing element; 32-Magnetic element; 33-Housing; 34-Main body of hammer; 35-Hammer head; 36-Hammer fixing assembly; 361-Sliding block; 362-Iron core; 363-Elastic component; 364-Second electromagnetic coil; 365-First brush head; 37-Second distance sensing element; 41-Position sensing element; 42-Switch unit; K-First electrical connection point; K1-Second electrical connection point; K2-Third electrical connection point; 43-Second brush head; 50-Elastic component to be tested; 60-Telescopic mechanism; Detailed Implementation

[0045] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0046] It is readily understood that, based on the technical solution of this invention, various structural and implementation methods can be interchanged by those skilled in the art without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of the invention.

[0047] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the structures shown in the accompanying drawings. They are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive.

[0048] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a natural frequency detection system for an elastic component, comprising a base 10, a bracket 11, an electromagnetic excitation mechanism, a striking mechanism 30, a force sensing element 31, a vibration sensing element, and a controller.

[0049] Base 10, used to place the elastic component 50 to be tested;

[0050] The bracket 11 is mounted on the base 10 and is used to fix the electromagnetic vibration mechanism striking mechanism 30.

[0051] An electromagnetic excitation mechanism is connected to a controller and is used to generate excitation force based on the received target current.

[0052] A striking mechanism 30 is mounted on a bracket 11. The striking mechanism 30 is connected to an electromagnetic vibration mechanism. A magnetic element 32 is provided inside the striking mechanism 30 for striking the elastic component 50 to be tested according to the excitation force.

[0053] Force sensing element 31 is disposed on the striking mechanism 30. Force sensing element 31 is communicatively connected to the controller and is used to detect the real-time striking force of the striking mechanism 30.

[0054] A vibration sensing element is disposed on the elastic component 50 to be tested, and is used to detect the vibration response of the elastic component 50 to be tested;

[0055] The controller is used to calculate the target current based on the target striking force received for controlling the striking mechanism 30, and to control the striking mechanism 30 away from the elastic component 50 under test based on the real-time striking force and the target striking force, and to calculate the natural frequency of the elastic component 50 under test based on the vibration response.

[0056] The elastic component natural frequency detection system provided by the present invention mainly includes a base 10, a bracket 11, an electromagnetic excitation mechanism, a striking mechanism 30, a force sensing element 31, a vibration sensing element, and a controller.

[0057] The base 10 is used to place the elastic component 50 to be tested, so that the elastic component 50 to be tested is located directly below the striking mechanism 30.

[0058] The bracket 11 is mounted on the base 10. The bracket 11 is used to fix the electromagnetic vibration mechanism striking mechanism 30, so that the striking mechanism 30 can move up and down along the vertical direction of the base 10.

[0059] The electromagnetic excitation mechanism is connected to the controller and generates excitation force according to the target current sent by the controller.

[0060] A striking mechanism 30 is mounted on the support 11 and connected to an electromagnetic vibration mechanism. The striking mechanism 30 contains a magnetic element 32. The magnetic element 32, driven by the excitation force generated by the electromagnetic vibration mechanism, moves the striking mechanism 30 up and down along the vertical direction of the base 10, thereby striking the elastic component 50 to be tested mounted on the base 10. The magnetic element 32 is preferably a magnet.

[0061] The force sensing element 31 is disposed on the striking mechanism 30. The force sensing element 31 can be integrated into the striking mechanism 30, mounted on the striking mechanism 30, or disposed on the striking mechanism 30 in other ways. Since the striking mechanism 30 needs to contact the elastic component 50 under test for a period of time before the applied force reaches the target striking force, the force sensing element 31 needs to detect the real-time striking force on the striking mechanism 30 and send it to the controller. The force sensing element 31 is preferably a force sensor.

[0062] The vibration sensing element can be placed directly on the elastic component under test during detection. It is used to detect the vibration response generated by the elastic component under test after being struck by the striking mechanism 30, and to determine whether the elastic component under test meets the requirements based on the vibration response. The vibration sensing element is preferably an acceleration sensor.

[0063] The controller calculates the target current based on the received target impact force. The target impact force can be determined according to the actual working conditions of the load set during vehicle operation; the greater the load, the greater the impact force. When the real-time impact force matches the target impact force, the controller controls the impact mechanism 30 to move away from the elastic component 50 under test, resetting the impact mechanism 30 and preparing it for the next impact. Simultaneously, the controller receives the vibration response detected by the vibration sensing element and calculates the natural frequency of the elastic component 50 under test based on the vibration response. It should be noted that the controller can use existing methods to calculate the natural frequency based on the vibration response, such as using the Fourier transform method to convert the real-time impact force detected by the force sensing element 31 and the vibration response detected by the vibration sensing element into frequency domain signals, then obtaining the transfer function based on the vibration response and the real-time impact force, and finally obtaining the natural frequency of the elastic component 50 under test through the transfer function. The specific method for the controller to calculate the natural frequency is not elaborated here. The controller is preferably a Programmable Logic Controller (PLC).

[0064] The elastic component natural frequency detection system provided by this invention comprises a base, a support, an electromagnetic excitation mechanism, a striking mechanism, a force sensing element, a vibration sensing element, and a controller. During testing, the elastic component to be tested is placed on the base. The controller calculates the target current required for the electromagnetic excitation mechanism to generate the excitation force based on the received target striking force. The striking mechanism strikes the elastic component to be tested according to the excitation force, and the real-time striking force of the striking mechanism is detected in real time. If the real-time striking force is consistent with the target striking force, the striking mechanism is controlled to move away from the elastic component to be tested, so that the striking mechanism resets. The vibration response of the elastic component to be tested is detected by the vibration sensing element, and the natural frequency of the elastic component to be tested is calculated based on the vibration response. This achieves automatic striking excitation, and the striking angle, force, and position are controllable, with high accuracy, no need for multiple manual operations, and high efficiency.

[0065] In one embodiment, the electromagnetic excitation mechanism includes a first electromagnetic coil 20 electrically connected to a power source, and the striking mechanism 30 includes a housing 33 having a hollow cavity, on which the first electromagnetic coil 20 is wound. The first electromagnetic coil 20 can be connected to and disconnected from the power source. A hammer body 34 is provided inside the housing 33, and a magnetic element 32 is provided inside the hammer body 34. A hammer head 35 is provided at one end of the hammer body 34, and a force sensing element 31 is provided on the hammer head 35.

[0066] The striking mechanism 30 includes a housing 33 with a hollow cavity in the middle, connecting opposite sides of the housing 33. A hammer body 34 is housed within the cavity, containing a magnetic element 32. The magnetic element 32 can be integrated into, mounted on, or otherwise disposed on the hammer body 34. A hammer head 35 is located at one end of the hammer body 34, extending from the bottom of the housing 33 to strike the elastic component 50 to be tested. The hammer head 35 can be integrally formed with the hammer body 34 or mounted on it in other ways. A force sensing element 31 is located on the hammer head 35, which can be integrated into, mounted on, or otherwise disposed on it. A first electromagnetic coil 21 is wound around the outer wall of the housing 33. When the first electromagnetic coil 21 is energized, the magnetic field of the magnetic element 32 is the same as that of the first electromagnetic coil 21.

[0067] In one embodiment, the power supply includes a first power supply component and a second power supply component, and the first electromagnetic coil 20 is capable of being switched on and off with the first power supply component.

[0068] The striking mechanism 30 also includes a hammer fixing assembly 36, which includes a sliding block 361, an iron core 362, an elastic component 363, and a second electromagnetic coil 364. The sliding block 361 and the iron core 362 are disposed at the other end of the hammer body 31. The iron core 362 is connected to the sliding block 361 through the elastic component 363. The iron core 362 is provided with a second electromagnetic coil 364, which can be connected and disconnected from the second power supply assembly.

[0069] The controller is also used for:

[0070] When the first electromagnetic coil 20 is about to be connected to or has been connected to the first power supply component with a first direction current, the second electromagnetic coil 364 is controlled to be energized or disconnected from the second power supply component or the current direction is changed so that the sliding block 361 can move relative to the housing 33. The first current direction is the current direction that can drive the striking mechanism 30 toward the elastic component 50 to be tested.

[0071] When the striking mechanism 30 moves away from the elastic component 50 under test, or when the striking mechanism 30 moves away from the elastic component 50 under test for a certain period of time or a certain distance, the second electromagnetic coil 364 is controlled to disconnect or connect with the second power supply assembly, or the current direction is changed, so that the sliding block 361 can move and be fixed relative to the housing 33. Second power supply assembly

[0072] The striking mechanism 30 also includes a hammer fixing assembly 36, which is used to fix the hammer body 34. The hammer fixing assembly 36 includes a sliding block 361 and an elastic member 363. One end of the hammer body 34 along the length of the housing 33 is provided with a hammer head 35, and the other end of the hammer body 34 is provided with a sliding block 361 and an iron core 362. The iron core 362 is connected to the sliding block 361 through the elastic member 363. A second electromagnetic coil 364 is wound around the iron core 362, and the second electromagnetic coil 364 is connected to the second power supply assembly. Specifically, the first power supply assembly and the second power supply assembly can be the same power supply or different power supplies. If the first power supply assembly and the second power supply assembly are different, the first electromagnetic coil 20 is electrically connected to the first power supply assembly, and the second electromagnetic coil 364 is electrically connected to the second power supply assembly; if the first power supply assembly and the second power supply assembly are the same, the first electromagnetic coil 20 and the second electromagnetic coil 364 are electrically connected. The first electromagnetic coil 20 and the second electromagnetic coil 364 can be formed by different wires and then electrically connected, or they can be formed by the same wire to form two coils.

[0073] When the elastic state of the elastic component 363 changes, the sliding block 361 can slide inside the housing 33 or remain stationary on the inner wall of the housing 33. Specifically, the elastic state of the elastic component 363 can be a change between tension and compression, between large and small amounts of tension and compression. The sliding block 361 can be a magnet or a magnetic material; changes in its magnetism and the arrangement of its magnetic poles will cause changes in the control method.

[0074] In one embodiment, when the first power supply component and the second power supply component are the same power supply, in order to facilitate the control of the first electromagnetic coil 20 and the second electromagnetic coil 364, the detection system further includes a switching unit 42. The switching unit 42 includes a first electrical connection point K and a second electrical connection point K1. The first electrical connection point K is used to connect to the power supply, and the second electrical connection point K2 is connected to the other end of the second electromagnetic coil 364. The first electrical connection point K and the second electrical connection point K2 can be connected and disconnected.

[0075] The striking mechanism 30 also includes a hammer fixing assembly 36, which is used to fix the hammer body 34. The hammer fixing assembly 36 includes a sliding block 361 and an elastic member 363. One end of the hammer body 34 along the length of the housing 33 is provided with a hammer head 35, and the other end of the hammer body 34 is provided with a sliding block 361 and an iron core 362. The iron core 362 is connected to the sliding block 361 through the elastic member 363, and a second electromagnetic coil 364 is wound around the iron core 362.

[0076] One end of the first electromagnetic coil 20 is connected to one end of the second electromagnetic coil 364, the other end of the first electromagnetic coil 20 is connected to the power supply, and the other end of the second electromagnetic coil 364 is connected to the second electrical connection point K1. By controlling the first electrical connection point K and the second electrical connection point K1 to be connected and disconnected, the connection and disconnection between the first electromagnetic coil 20 and the power supply can be realized.

[0077] When the first electrical connection point K and the second electrical connection point K1 are switched on and off, the elastic state of the elastic component 363 will change. As the elastic state of the elastic component 363 changes, the sliding block 361 can slide in the hollow cavity or be fixed to the inner wall of the hollow cavity.

[0078] In one embodiment, the switching unit 42 further includes a third electrical connection point K3. The other end of the first electromagnetic coil 20 is used for connecting the third electrical connection point K3 and the power supply component. When the first electrical connection point K is connected to the second electrical connection point K2, the second electrical connection point K2 is disconnected from the third electrical connection point K3. When the second electrical connection point K2 is connected to the third electrical connection point K3, the first electrical connection point K is disconnected from the second electrical connection point K2.

[0079] When the first electrical connection point K is connected to the second electrical connection point K1, the first electromagnetic coil 20 is connected to the power supply component and is in a conductive state. When the first electrical connection point K is connected to the third electrical connection point K2, the first electromagnetic coil 20 is disconnected from the power supply component and is in a de-energized state, but the first electromagnetic coil 20 and the second electromagnetic coil 364 form a closed circuit.

[0080] In one embodiment, when the first electromagnetic coil 20 is energized, the second electromagnetic coil 364 is also energized. The iron core 362 attracts the sliding block 361, which compresses the elastic component 363. The gap between the sliding block 361 and the housing 33 increases, and the magnetic field of the magnetic element 32 is the same as that of the first electromagnetic coil 20. Under the magnetic force of the second electromagnetic coil 25, the magnetic element 32 drives the striking mechanism 30 to accelerate downward and strike the elastic component 50 to be tested, which is mounted on the base 10. When the force sensing element 31 detects... When the real-time striking force of the striking mechanism 30 matches the target striking force, the force sensing element 31 sends a reset signal to the controller. The controller then controls the power supply assembly to input a reverse current to the first electromagnetic coil 20, controlling the striking mechanism 30 to move upwards in a direction away from the elastic component 50 being tested, until the second electromagnetic coil 364 is de-energized and no longer generates suction. The elastic component 363 rebounds, the deformation of the sliding block 361 is restored, the gap between the sliding block 361 and the housing 33 decreases, and the striking mechanism 30 is fixed, thus resetting the striking mechanism 30. The elastic component 363 is preferably a spring.

[0081] Preferably, to prevent the wires of the second electromagnetic coil 364 from getting tangled during repeated up-and-down movements or to facilitate the installation and fixing of its wires, a first brush head 365 is provided on the inner wall of the housing 33. One end of the second electromagnetic coil 364 is electrically connected to the first electromagnetic coil 20 through the brush head 365, and the other end of the second electromagnetic coil 364 is electrically connected to the third electrical connection point K3 through the first brush head 365.

[0082] In one embodiment, in order to facilitate the control of the striking mechanism 30 to reset, when the real-time striking force detected by the force sensing element 31 reaches the target striking force, the force sensing element 31 sends a reset signal to the controller, and the controller controls the power supply component to change the direction of the current applied to the first electromagnetic coil 20, driving the striking mechanism 30 away from the elastic component 50 to be tested.

[0083] In one embodiment, to facilitate the switching of the control switch unit on and off, the detection system further includes a position sensing element 41. The position sensing element 41 is used to detect the position of the force sensing element 31. When the force sensing element 31 is not detected or the position of the force sensing element 31 exceeds a preset value or a preset range, the first electrical contact K1 and the second electrical contact K2 of the control switch unit 20 are disconnected or the second electrical contact K2 and the third electrical contact K3 are connected. The position sensing element 41 covers the bottom of the housing 33. When the hammer body 34 rebounds, the force sensing element 31 enters the housing 33, and at this time, the position sensing element 41 detects the force sensing element 31. When the hammer body 34 continues to rebound away from the elastic component 50 to be tested, and the force sensing element 31 exceeds the detection range of the position sensing element 41 or exceeds a preset threshold or range, the position sensing element 41 does not detect the force sensing element 31 and sends a reset signal to the controller.

[0084] When the elastic component 50 under test needs to be struck, the controller controls the power supply component to input a positive current to the first electromagnetic coil 20. At this time, the first electromagnetic coil 20 is in a conductive state, and the electromagnetic excitation mechanism drives the striking mechanism 30 to accelerate downward and strike the elastic component 50 under test, which is mounted on the base 10. When the real-time striking force is consistent with the target striking force, the controller controls the power supply component to input a reverse current to the first electromagnetic coil 20, causing the striking mechanism 30 to rebound. Specifically, the controller can control the power supply component to input a positive current to the first electromagnetic coil 20 by receiving a signal that the power supply component and the first electromagnetic coil 20 are connected, a signal that the target striking force has been determined or executed, a signal that the striking hammer is in position, or other striking command signals.

[0085] After the striking mechanism 30 rebounds, if the position sensing element 41 does not detect the force sensing element 31, a trigger signal is sent to the controller. The controller controls the switching unit 42 to switch the second electrical connection point K2 and the third electrical connection point K3 to be connected. The coil of the first electromagnetic coil 20 is in a short-circuit state. Due to Lenz's law, the first electromagnetic coil 20 will generate an induced current to form a magnetic field. The direction of the generated magnetic field is opposite to the direction of the magnetic field of the magnetic element 32 in the hammer body 34, causing the hammer body 34 to decelerate. At the same time, the magnetic element 32 moves in the first electromagnetic coil 20, and the total magnetic flux through the first electromagnetic coil 20 changes, generating an induced current. The induced current passes through the second electromagnetic coil 364, and the iron core 362 generates an attractive force to compress the elastic component 363 until the hammer body 34 stops moving. After that, the total magnetic flux in the first electromagnetic coil 20 remains unchanged, and no induced current is generated. The second electromagnetic coil 364 is de-energized, the elastic component 363 resets, and the sliding block 361 contacts the inner wall of the housing 33, fixing the striking mechanism 30 and resetting the striking mechanism 30.

[0086] Preferably, in order to facilitate the generation of a magnetic field by energizing, a second brush head 43 is also included. The second brush head 43 is disposed in the lower part of the inner wall of the hollow cavity. A buffer zone is provided between the first brush head 365 and the second brush head 43. The buffer zone refers to the situation when the first electromagnetic coil 20 is short-circuited.

[0087] In one embodiment, the detection system further includes a telescopic mechanism 60, one end of which is connected to the base 10 and the other end of which is connected to the bracket 11. The bracket 11 moves vertically to the base 10 via the telescopic mechanism 60.

[0088] The telescopic mechanism 60 is used to adjust the distance between the striking mechanism 30 and the elastic component 50 to be tested. If the distance between the striking mechanism 30 and the elastic component 50 is too large, the telescopic mechanism 60 retracts, shortening the distance between them; if the distance is too small, the telescopic mechanism 60 extends, increasing the distance between them. The telescopic mechanism 60 can adopt an existing structure, so its specific structure will not be described in detail.

[0089] Preferably, a first distance sensing element 111 is provided at the end of the bracket 11 near the base 10, and a second distance sensing element 37 is provided at the end of the hammer body 34 away from the base 10. The first distance sensing element 111 is used to detect the distance between the striking mechanism 30 and the elastic component 50 to be tested, and the second distance sensing element 37 is used to detect the distance between the end of the hammer body 34 away from the base 10 and the elastic component 50 to be tested. The distance between the hammer head 35 and the elastic component 50 to be tested is calculated by the first distance sensing element 111 and the second distance sensing element 37, thereby determining the target striking force, adapting to elastic components of different heights, and improving compatibility. The first distance sensing element 111 is preferably a laser distance sensor, and the second distance sensing element 37 is preferably a grating sensor.

[0090] In one embodiment, the detection system further includes a rotating mechanism (not shown), one end of which is connected to the base 10 and the other end of which is connected to the bracket 11. The bracket 11 rotates in the vertical direction around the base 10 via the rotating mechanism.

[0091] The rotating mechanism is used to adjust the angle between the striking mechanism 30 and the elastic component 50 to be tested. If there is a deviation in the angle between the striking mechanism 30 and the elastic component 50, the bracket 11 is adjusted by the rotating mechanism to align the striking mechanism 30 with the elastic component 50, thus avoiding deviation in the angle of the striking force and further improving accuracy. The rotating mechanism can adopt an existing structure, so its specific structure will not be described in detail.

[0092] like Figure 3 As shown, Figure 3 This is a flowchart illustrating the detection method of a natural frequency detection system for an elastic component according to an embodiment of the present invention, including:

[0093] Step S301: Receive the target striking force for controlling the striking mechanism;

[0094] Step S302: Calculate the target current used to control the electromagnetic excitation mechanism to generate excitation force based on the target impact force;

[0095] Step S303: Acquire the real-time striking force of the striking mechanism, and control the striking mechanism to move away from the elastic component under test based on the real-time striking force and the target striking force;

[0096] Step S304: Receive the vibration response of the elastic component under test, and calculate the natural frequency of the elastic component under test based on the vibration response.

[0097] Specifically, when it is necessary to detect the natural frequency of the elastic component under test, the elastic component under test is placed on the base, the angle between the striking mechanism and the elastic component under test is adjusted so that the striking mechanism is aligned with the elastic component under test, and the target striking force is input. The controller executes step S301 to receive the target striking force, and then executes step S302 to calculate the target current for controlling the electromagnetic excitation mechanism to generate the excitation force based on the target striking force, so that the input current of the first electromagnetic coil is the target current; then executes step S303 to obtain the real-time striking force of the striking mechanism. If the real-time striking force is consistent with the target striking force, the striking mechanism is controlled to move away from the elastic component under test, so that the striking mechanism is reset; finally executes step S304 to receive the vibration response of the elastic component under test detected by the vibration sensing element, and calculates the natural frequency of the elastic component under test based on the vibration response, realizing automatic striking excitation. The striking angle, force and position are controllable, the accuracy is high, and multiple manual operations are not required, resulting in high efficiency.

[0098] The detection method provided by this invention,

[0099] In one embodiment, step S302 includes:

[0100] The target current can be calculated using the following formula:

[0101]

[0102] Where H is the magnetic field strength of the magnetic element; N is the number of turns of the first electromagnetic coil; I is the target current; Le is the effective magnetic circuit length; m is the mass of the magnetic element; x is the specific magnetization coefficient of the magnetic element; v is the volume of the magnetic element; and gradH is the magnetic field gradient.

[0103] In one embodiment, to facilitate the control of the striking mechanism's reset, step S303 includes:

[0104] Received a reset signal from the position sensing element;

[0105] The control power supply component changes the direction of the current applied to the first electromagnetic coil, driving the striking mechanism away from the elastic component under test.

[0106] When the real-time striking force matches the target striking force, a reverse current is input to the first electromagnetic coil, causing the striking mechanism to rebound. After the striking mechanism rebounds, if the position sensing element detects the force sensing element, it sends a reset signal to the controller. The controller controls the switching unit to switch the second electrical connection point and the third electrical connection point to be connected. The coil of the first electromagnetic coil is in a short-circuit state. Due to Lenz's law, the first electromagnetic coil will generate an induced current to form a magnetic field. The direction of the generated magnetic field is opposite to the direction of the magnetic field of the magnetic element in the hammer body, causing the hammer body to decelerate. At the same time, the magnetic element moves in the first electromagnetic coil, and the total magnetic flux through the first electromagnetic coil changes, generating an induced current. The induced current passes through the second electromagnetic coil, and the iron core generates an attractive force to compress the elastic component until the hammer body stops moving. After that, the total magnetic flux in the first electromagnetic coil remains unchanged, and no induced current is generated. The second electromagnetic coil is de-energized, the elastic component resets, the sliding block contacts the inner wall of the shell, and the striking mechanism is fixed, thus resetting the striking mechanism.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the embodiments of the present invention have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for detecting the natural frequency of an elastic component, characterized in that, Includes a base, bracket, electromagnetic excitation mechanism, striking mechanism, force sensing element, vibration sensing element, and controller. The base is used to hold the elastic component to be tested. A bracket is used to fix the striking mechanism; An electromagnetic vibration mechanism is communicatively connected to a controller and is used to generate excitation force based on a received target current. The electromagnetic vibration mechanism includes a first electromagnetic coil. The striking mechanism includes a housing with a hollow cavity, on which the first electromagnetic coil is wound. The first electromagnetic coil can be connected to and disconnected from a power source. A hammer body is provided inside the housing, and a magnetic element is provided inside the hammer body. A hammer head is provided at one end of the hammer body, and a force sensing element is provided on the hammer head. The power source includes a first power supply component and a second power supply component. The first electromagnetic coil can be connected to and disconnected from the first power supply component. The first power supply component and the second power supply component can be the same power supply or different power supplies. A striking mechanism is mounted on the bracket and connected to the electromagnetic excitation mechanism. The striking mechanism contains the magnetic element for striking the elastic component under test according to the excitation force. The striking mechanism also includes a hammer fixing assembly, which includes a sliding block, an iron core, an elastic component, and a second electromagnetic coil. The sliding block and the iron core are located at the other end of the hammer body. The iron core is connected to the sliding block through the elastic component. The iron core is equipped with the second electromagnetic coil, which can be connected and disconnected from the second power supply assembly. A force sensing element is disposed on the striking mechanism. The force sensing element is communicatively connected to the controller and is used to detect the real-time striking force of the striking mechanism. A vibration sensing element is disposed on the elastic component under test and is used to detect the vibration response of the elastic component under test. The controller is configured to calculate the target current based on the target striking force received for controlling the striking mechanism, and control the striking mechanism away from the elastic component under test based on the real-time striking force and the target striking force, and calculate the natural frequency of the elastic component under test based on the vibration response; when the first electromagnetic coil is about to be connected to or has been connected to the first directional current of the first power supply component, the controller controls the second electromagnetic coil to be energized or disconnected from the second power supply component or the current direction to change, so that the sliding block can move relative to the housing, wherein the first directional current is the current direction that can drive the striking mechanism toward the elastic component under test; When the striking mechanism moves away from the elastic component under test, or when the striking mechanism moves away from the elastic component under test for a certain period of time or a certain distance, the second electromagnetic coil is controlled to disconnect or connect with the second power supply component or change the direction of the current so that the sliding block can move and be fixed relative to the housing.

2. The elastic component natural frequency detection system as described in claim 1, characterized in that, When the first power supply component and the second power supply component are the same power supply, the detection system further includes a switching unit. The switching unit includes a first electrical connection point and a second electrical connection point. The first electrical connection point is used to connect to the power supply, and the first electrical connection point and the second electrical connection point can be connected and disconnected. One end of the first electromagnetic coil is connected to one end of the second electromagnetic coil, the other end of the first electromagnetic coil is connected to the power source, and the other end of the second electromagnetic coil is connected to the second electrical connection point. By controlling the first electrical connection point and the second electrical connection point to be connected and disconnected, the connection and disconnection between the first electromagnetic coil and the power source can be realized. When the first electrical connection point and the second electrical connection point are switched on and off, the elastic state of the elastic component will change. As the elastic state of the elastic component changes, the sliding block can slide in the hollow cavity or be fixed to the inner wall of the hollow cavity.

3. The elastic component natural frequency detection system as described in claim 2, characterized in that, The switching unit further includes a third electrical connection point. The other end of the first electromagnetic coil is used for connecting the third electrical connection point and the power supply. When the first electrical connection point is connected to the second electrical connection point, the second electrical connection point is disconnected from the third electrical connection point. When the second electrical connection point is connected to the third electrical connection point, the first electrical connection point is disconnected from the second electrical connection point.

4. The elastic component natural frequency detection system as described in claim 3, characterized in that, The detection system further includes a position sensing element, which is used to detect the position of the force sensing element. When the force sensing element is not detected or the position of the force sensing element exceeds a preset value or a preset range, the system controls the first electrical connection point and the second electrical connection point of the switching unit to disconnect or the second electrical connection point and the third electrical connection point to connect.

5. The elastic component natural frequency detection system according to any one of claims 1-4, characterized in that, The detection system also includes a telescopic mechanism, one end of which is connected to the base and the other end of which is connected to the bracket. The bracket moves along the vertical direction of the base via the telescopic mechanism.

6. The elastic component natural frequency detection system as described in claim 5, characterized in that, The detection system also includes a rotating mechanism, one end of which is connected to the base and the other end of which is connected to the bracket. The bracket rotates along the vertical direction around the base via the rotating mechanism.

7. A detection method for a natural frequency detection system for an elastic component as described in any one of claims 1-6, characterized in that, include: Receives a target striking force for controlling the striking mechanism; Calculate the target current used to control the electromagnetic excitation mechanism to generate excitation force based on the target impact force; The real-time striking force of the striking mechanism is acquired in real time, and the striking mechanism is controlled to move away from the elastic component under test based on the real-time striking force and the target striking force. The vibration response of the elastic component under test is received, and the natural frequency of the elastic component under test is calculated based on the vibration response.

8. The detection method as described in claim 7, characterized in that, The step of calculating the target current for controlling the electromagnetic excitation mechanism to generate excitation force based on the target impact force includes: The target current is calculated using the following formula: in, The magnetic field strength of the magnetic element; The number of turns of the first electromagnetic coil of the electromagnetic excitation mechanism; The target current; The effective magnetic circuit length; The mass of the magnetic element; The specific magnetization coefficient of the magnetic element; The volume of the magnetic element; This represents the magnetic field gradient.

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