Transmission tower bolt looseness detection system and method based on impact elastic waves

Abstract

The invention provides a power transmission tower bolt looseness detection system and method based on impact elastic waves, and the system comprises an electromagnetic impact excitation device, a piezoelectric acceleration sensor, a signal collection module, a signal processing unit and a power control module. The signal acquisition module is used for coupling elastic waves generated by impact to a bolt and a surrounding structure thereof so as to cause vibration, the piezoelectric acceleration sensor is arranged on the surface of an iron tower structure which is not more than 10cm away from the to-be-detected bolt and is used for receiving an induced vibration signal, and the signal acquisition module is connected with the piezoelectric acceleration sensor through a cable and is used for acquiring the vibration signal. The signal processing unit is used for analyzing the received vibration signals and extracting characteristic parameters so as to judge the loosening state of the bolt, and the power supply control module provides power support. According to the invention, the loosening state of the bolt can be rapidly judged under non-destructive operation, and the detection precision and reliability are improved.

Description

Technical Field

[0001] The present application relates to the technical field of power transmission line maintenance, and in particular to a transmission tower bolt loosening detection system and method based on impact elastic waves. Background Art

[0002] In the power transmission system, tower bolts are important components to keep the tower structure stable and safe. Due to the external forces in the environment and long-term operation, the bolts may become loose, which will bring hidden dangers to the overall stability of the transmission system. Therefore, how to timely and accurately detect the loose state of tower bolts is an important task that cannot be ignored in the maintenance of transmission lines.

[0003] At present, the detection technologies for loose tower bolts mainly include manual inspection and the use of simple vibration detection devices. Although manual inspection can intuitively find problems, it requires professionals to approach the tower and check one by one, which is dangerous and has certain subjective errors. Although the existing automated detection equipment can collect vibration signals, it often fails to achieve effective signal coupling in the process of transmitting vibration signals to the bolts and surrounding structures. Insufficient signal coupling will cause signal distortion and fail to effectively reflect the loose state of the bolts, resulting in insufficient accuracy of the detection results. Therefore, a detection system that can achieve reliable vibration signal transmission and reception in the bolt area is needed to improve detection accuracy. Summary of the invention

[0004] In order to solve the problems in the above-mentioned background technology, the present application provides a transmission tower bolt loosening detection system and method based on impact elastic wave to improve the detection accuracy.

[0005] In a first aspect, the present application provides a transmission tower bolt loosening detection system based on impact elastic waves, comprising an electromagnetic impact excitation device, a piezoelectric acceleration sensor, a signal acquisition module, a signal processing unit and a power supply control module; The electromagnetic shock excitation device is arranged directly below or above the bolt connection of the transmission tower, and is used to couple the elastic wave generated by the shock to the bolt and the surrounding structure of the bolt to cause vibration; the piezoelectric acceleration sensor is arranged on the surface of the tower structure no more than 10 cm away from the bolt to be detected and is in contact with the surface of the tower structure, and is used to receive the vibration signal caused by the electromagnetic shock excitation device; the signal acquisition module is connected to the piezoelectric acceleration sensor through a cable, and is used to receive and amplify the vibration signal collected by the piezoelectric acceleration sensor; the signal processing unit is connected to the signal acquisition module through a cable, and is used to analyze the received vibration signal to determine the loose state of the bolt; the power control module is connected to the electromagnetic shock excitation device, the signal acquisition module and the signal processing unit through cables, respectively, and is used to provide power support; The electromagnetic impact excitation device includes a shell, an electromagnetic coil, a movable impact head, a spring guide mechanism and a fixed base; the electromagnetic coil is installed in the middle position inside the shell, the electromagnetic coil is wound into a spiral structure and can form an axial magnetic field in the shell after power is turned on, and an impact port is opened at the end of the shell for the movable impact head to extend out; the movable impact head is made of ferromagnetic material, located in the central area of ​​the electromagnetic coil with its front end facing the impact port of the shell, the rear end of the movable impact head is connected to the spring guide mechanism, and the fixed base is arranged at the bottom end of the shell.

[0006] As an optional solution of the present application, a supporting device is provided at the bottom end of the electromagnetic impact excitation device, and the supporting device includes a support with a magnetic attraction function, a retractable connecting sleeve, and an angle adjustment mechanism capable of adjusting the tilt angle of the electromagnetic impact excitation device; A plurality of groups of neodymium magnets are embedded at the bottom end of the support, the support is fixedly connected with the connecting sleeve, the other end of the connecting sleeve is provided with the angle adjustment mechanism, a connecting plate with a connecting ring is connected to the angle adjustment mechanism, a rubber pad is pasted on the upper surface of the connecting plate, the connecting plate is connected to the bottom end of the electromagnetic shock excitation device by four bolts, and the rubber pad is located between the connecting plate and the bottom end of the electromagnetic shock excitation device; The signal acquisition module, the signal processing unit and the power control module are all arranged inside the support.

[0007] As an optional solution of the present application, a protective shell is provided at the top of the piezoelectric acceleration sensor, and connection holes are respectively opened on the left and right sides of the protective shell. The protective shell is connected to a bracket located on the outside of the piezoelectric acceleration sensor through the two connection holes, and the lower ends of the bracket are respectively connected to spring clips for fixing the bracket to the iron tower structure, so that the piezoelectric acceleration sensor can be fixed.

[0008] As an optional solution of the present application, the connecting hole is a threaded connecting hole, and the bracket is composed of a first connecting rod and a second connecting rod located on the left and right sides of the protective shell, and the first connecting rod and the second connecting rod both include a threaded connecting rod, an L-shaped transition rod, a vertical spring and a vertical connecting rod; The threaded connecting rod, the L-shaped transition rod, the vertical spring and the vertical connecting rod are connected in sequence, one end of the threaded connecting rod is threadedly connected to the connecting hole, the other end of the threaded connecting rod is rotatably connected to the L-shaped transition rod, the other end of the L-shaped transition rod is fixedly connected to the vertical spring and connected to the vertical connecting rod through the vertical spring, and the end of the vertical connecting rod is connected to the spring clip; A plurality of cable guide clamps are arranged on the rod body of the vertical connecting rod, and the guide clamps are C-shaped clamps with openings.

[0009] As an optional solution of the present application, the spring guide mechanism includes a guide rod, a compression spring and a guide tube, the fixed base is connected to the rear end of the shell, the fixed base is provided with the guide tube located in the shell, the guide rod is arranged in the guide tube and slidably cooperates with the guide tube, the front end of the guide rod is connected to the rear end of the movable impact head, and the compression spring is also connected between the rear end of the movable impact head and the front end of the guide tube.

[0010] As an optional solution of the present application, the power control module includes a power output interface, a power control unit, a power indicator light, an input power interface, an adjustment knob and a BNC interface; The power output interface is used to connect to the electromagnetic shock excitation device, the signal acquisition module, the signal processing unit and the power control module respectively, so as to provide stable power; The power control unit adopts a pulse width modulation (PWM) controller, which is used to adjust the pulse frequency and pulse width of the output current according to the setting of the adjustment knob to control the impact frequency and strength of the electromagnetic impact excitation device; The power indicator light is used to display the working status of the power control module; The input power interface is used to connect to an external power source for power supply; The adjusting knob is used to manually adjust the pulse frequency and pulse width of the power control unit; The power output interface, the power indicator light, the input power interface and the adjustment knob are respectively arranged on the support, and the power control unit is arranged inside the support; the power output interface is connected to the electromagnetic impact excitation device and the signal acquisition module through a shielded cable, and the piezoelectric acceleration sensor and the signal acquisition module, as well as the signal acquisition module and the signal processing unit are respectively connected by shielded cables; the support is also provided with the BNC interface for connecting the piezoelectric acceleration sensor and the signal acquisition module through a shielded cable.

[0011] As an optional solution of the present application, the angle adjustment mechanism includes a rotating support, a connecting shaft and a locking knob. The rotating support is connected to the end of the connecting sleeve away from the support. The rotating support is a cylindrical structure adapted to the connecting ring. The connecting shaft is movably connected to the middle part of the rotating support. The locking knobs are respectively threadedly connected to both ends of the connecting shaft. The rotating support is fixedly connected to the connecting ring, and the connecting ring is fixedly connected to the connecting plate.

[0012] As an optional solution of the present application, the signal processing unit includes a signal amplifier, a filter, an analog-to-digital converter and a digital signal processor; The signal amplifier is connected to the signal acquisition module and is used to amplify the received vibration signal; The filter is connected to the output end of the signal amplifier and is used to remove noise from the amplified signal and extract the signal within the target frequency range; The analog-to-digital converter is connected to the output end of the filter and is used to convert the filtered analog vibration signal into a digital signal; The digital signal processor is connected to the output end of the analog-to-digital converter and is used to analyze the digitized vibration signal and extract waveform characteristic parameters to determine the loose state of the bolt.

[0013] On the other hand, the present application also provides a method for detecting loose bolts of a transmission tower based on impact elastic waves, which uses the above-mentioned transmission tower bolt loose detection system based on impact elastic waves of the present application, and comprises the following steps: Step 1, installing an electromagnetic shock excitation device just below or just above the bolt connection of the transmission tower, and providing a pulse current to the electromagnetic shock excitation device through a power control module to drive a movable impact head to generate an impact elastic wave; Step 2: transmitting the impact elastic wave to the bolt and its surrounding structure through the movable impact head, causing vibration in the bolt area; Step 3: a piezoelectric acceleration sensor is arranged at a position no more than 10 cm away from the bolt to be detected, in contact with the tower structure, to collect vibration signals caused by elastic waves; Step 4: Transmit the collected vibration signal to the signal acquisition module through a shielded cable for signal amplification; Step 5: Transmit the amplified signal to the signal processing unit to analyze and extract the signal characteristic parameters to determine whether the bolt is loose.

[0014] Optionally, in step 1, the frequency and pulse width of the pulse current are adjusted by a pulse width modulation controller in the power control module to control the impact frequency and strength of the movable impact head; In step 5, the signal characteristic parameters extracted by the signal processing unit include main frequency, amplitude and envelope characteristic parameters.

[0015] Compared with the prior art, this application has the following beneficial effects: 1. The electromagnetic shock excitation device of the application is designed with a structure consisting of a shell, an electromagnetic coil, a movable impact head, a spring guide mechanism and a fixed base. The electromagnetic coil is installed inside the shell and wound into a spiral structure, which can form a stable axial magnetic field after power is turned on, and drive the movable impact head to generate precise impact elastic waves. By positioning the movable impact head below or above the bolt, the impact elastic wave can be directly transmitted to the bolt and its surrounding structure. This method enhances the transmission effect of the vibration signal, realizes effective signal coupling, improves the accuracy of wave transmission, and reduces the attenuation of the vibration signal, thereby effectively overcoming the signal distortion problem in the prior art.

[0016] 2. In the present application, the piezoelectric acceleration sensor is set at a position no more than 10 cm away from the bolt to be detected and in contact with the surface of the tower structure. This method can make the piezoelectric acceleration sensor close to the bolt and contact the surface of the structure, which can improve the reception effect of the vibration signal and avoid signal attenuation and distortion caused by long distance or poor contact. Therefore, this method helps to accurately judge the looseness state of the bolt while ensuring the clarity and accuracy of signal reception.

[0017] 3. In this application, the vibration signal is initially amplified and then transmitted to the signal processing unit for in-depth analysis through the cooperation of the signal acquisition module and the signal processing unit. Such a signal transmission design can not only effectively reduce noise, but also analyze the received vibration signal through the signal processing unit to determine the looseness status of the bolt. Moreover, the power control module provides power support to each component through cables, thereby ensuring the stability and continuous operation of the entire detection system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 A system configuration diagram of a transmission tower bolt loosening detection system based on impact elastic waves provided in one embodiment of the present application; Figure 2 A schematic diagram of an electromagnetic shock excitation device provided in one embodiment of the present application on a supporting device; Figure 3 A schematic diagram of the structure of an angle adjustment mechanism on a support device provided in one embodiment of the present application; Figure 4 A schematic diagram of the interior of an electromagnetic shock excitation device provided in one embodiment of the present application; Figure 5 A schematic diagram of the structure of a spring guide mechanism provided in one embodiment of the present application; Figure 6 A schematic diagram of the connection between the piezoelectric acceleration sensor and the protective shell provided in one embodiment of the present application; Figure 7 A schematic diagram of the structure of a bracket provided in one embodiment of the present application; Figure 8 A schematic diagram of the structure of a power control module provided in one embodiment of the present application; Fig. 9 A schematic diagram of the structure of a signal processing unit provided in one embodiment of the present application.

[0020] In the figure, 100, electromagnetic impact excitation device; 110, housing; 120, electromagnetic coil; 130, movable impact head; 140, spring guide mechanism; 141, guide rod; 142, compression spring; 143, guide tube; 150, fixed base; 200, piezoelectric acceleration sensor; 210, protective shell; 211, connecting hole; 212, bracket; 2121, threaded connecting rod; 2122, L-shaped transition rod; 2123, vertical spring; 2124, vertical connecting rod; 21241, guide clamp; 213, spring clip; 300, signal acquisition module; 400, signal processing unit; 410, signal amplifier; 420, filter; 430, analog-to-digital converter; 440, digital signal processor; 500, power control module; 510, power output interface; 520, power control unit; 530, power indicator light; 540, input power interface; 550, adjustment knob; 560, BNC interface; 600, supporting device; 610, support; 620, connecting sleeve; 621, adjustment knob; 630, angle adjustment mechanism; 631, rotating support; 632, connecting shaft; 633, locking knob; 640, connecting plate; 641, connecting ring; 642, rubber pad. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work also fall within the scope of protection of the present application.

[0022] See also Figure 1-Figure 9 ,in, Figure 1 A system configuration diagram of a transmission tower bolt loosening detection system based on impact elastic waves provided in one embodiment of the present application; Figure 2A schematic diagram of an electromagnetic shock excitation device provided in one embodiment of the present application on a supporting device; Figure 3 A schematic diagram of the structure of an angle adjustment mechanism on a support device provided in one embodiment of the present application; Figure 4 A schematic diagram of the interior of an electromagnetic shock excitation device provided in one embodiment of the present application; Figure 5 A schematic diagram of the structure of a spring guide mechanism provided in one embodiment of the present application; Figure 6 A schematic diagram of the connection between the piezoelectric acceleration sensor and the protective shell provided in one embodiment of the present application; Figure 7 A schematic diagram of the structure of a bracket provided in one embodiment of the present application; Figure 8 A schematic diagram of the structure of a power control module provided in one embodiment of the present application; Fig. 9 FIG. 1 is a schematic diagram of a signal processing unit according to an embodiment of the present application. Figure 1 As shown, an embodiment of the present application provides a transmission tower bolt loosening detection system based on impact elastic waves, including an electromagnetic impact excitation device 100, a piezoelectric acceleration sensor 200, a signal acquisition module 300, a signal processing unit 400 and a power control module 500.

[0023] Among them, the electromagnetic shock excitation device 100 is arranged just below or just above the bolt connection of the transmission tower, and is used to couple the elastic wave generated by the impact to the bolt and the surrounding structure of the bolt to cause vibration; the piezoelectric acceleration sensor 200 is arranged on the surface of the tower structure no more than 10 cm away from the bolt to be detected and is in contact with the surface of the tower structure, and is used to receive the vibration signal caused by the electromagnetic shock excitation device 100; the signal acquisition module 300 is connected to the piezoelectric acceleration sensor 200 through a cable, and is used to receive and amplify the vibration signal collected by the piezoelectric acceleration sensor 200; the signal processing unit 400 is connected to the signal acquisition module 300 through a cable, and is used to analyze the received vibration signal to determine the loose state of the bolt; the power control module 500 is connected to the electromagnetic shock excitation device 100, the signal acquisition module 300 and the signal processing unit 400 through cables respectively, and is used to provide power support.

[0024] like Figure 2-Figure 4As shown, the electromagnetic impact excitation device 100 includes a shell 110, an electromagnetic coil 120, a movable impact head 130, a spring guide mechanism 140 and a fixed base 150; the electromagnetic coil 120 is installed in the middle position inside the shell 110, the electromagnetic coil 120 is wound into a spiral structure and can form an axial magnetic field in the shell 110 after power is turned on, and an impact port for the movable impact head 130 to extend is opened at the end of the shell 110; the movable impact head 130 is made of ferromagnetic material, located in the central area of ​​the electromagnetic coil 120 with the front end facing the impact port of the shell 110. In this embodiment, optionally, the movable impact head 130 is made of silicon steel material, which is a ferromagnetic material with high magnetic permeability and can effectively respond to the magnetic field generated by the electromagnetic coil. In addition, the silicon steel contains an appropriate amount of silicon element, which reduces the eddy current loss caused by the alternating magnetic field, thereby improving the efficiency of the material under the action of the electromagnetic field, so that the movable impact head 130 can still remain stable when frequently powered on. In addition, silicon steel has good mechanical strength and durability, can withstand high-frequency impact and long-term repetitive movement, and is not easy to deform or fail. The rear end of the movable impact head 130 is connected to the spring guide mechanism 140, and the fixed base 150 is arranged at the bottom end of the shell 110. During use, the electromagnetic impact excitation device 100 drives the movable impact head 130 to perform axial impact through the axial magnetic field generated by the electromagnetic coil 120. When the electromagnetic coil 120 is energized, the generated magnetic field pushes the movable impact head 130 to move forward, impacts the surface of the tower structure, forms an impact elastic wave, and completes the impact action.

[0025] The electromagnetic shock excitation device 100 adopted in the embodiment of the application has a structural design consisting of a shell 110, an electromagnetic coil 120, a movable impact head 130, a spring guide mechanism 140 and a fixed base 150. The electromagnetic coil 120 is installed inside the shell 110 and wound into a spiral structure. It can form a stable axial magnetic field after power is turned on, and drive the movable impact head 130 to generate precise shock elastic waves. By positioning the movable impact head 130 below or above the bolt, the shock elastic wave can be directly transmitted to the bolt and its surrounding structure. This method enhances the transmission effect of the vibration signal, realizes effective signal coupling, improves the accuracy of wave transmission, and reduces the attenuation of the vibration signal, thereby effectively overcoming the problem of signal distortion in the prior art.

[0026] At the same time, the embodiment of the present application sets the piezoelectric acceleration sensor 200 at a position no more than 10 cm away from the bolt to be detected and in contact with the surface of the tower structure. This method can make the piezoelectric acceleration sensor 200 close to the bolt and contact the surface of the structure, which can improve the reception effect of the vibration signal and avoid signal attenuation and distortion caused by long distance or poor contact. Therefore, this method helps to accurately judge the looseness state of the bolt while ensuring the clarity and accuracy of signal reception.

[0027] In addition, in the embodiment of the present application, through the cooperation between the signal acquisition module 300 and the signal processing unit 400, the vibration signal is transmitted to the signal processing unit 400 for in-depth analysis after preliminary amplification. Such a signal transmission design can not only effectively reduce noise, but also analyze the received vibration signal through the signal processing unit to determine the looseness status of the bolt. Moreover, the power control module 500 provides power support to each component through cables, thereby ensuring the stability and continuous operation of the entire detection system.

[0028] In practical applications, a non-magnetic spacer is provided at the end of the movable impact head 130. When in use, the non-magnetic spacer is fixedly provided at the end of the movable impact head 130 for impact. Optionally, an adhesive is used to fix the non-magnetic spacer on the end surface of the movable impact head 130 so that it will not loosen or shift during impact. The non-magnetic spacer can be selected from plastic, composite materials or ceramic sheets. When ceramic sheets are selected as non-magnetic spacers, alumina ceramics and silicon nitride ceramics can be selected. These materials are not affected by magnetic fields and have good durability and mechanical strength. The shape of the non-magnetic spacer is designed to be circular or a planar structure that matches the shape of the movable impact head 130 to ensure that it can fit closely with the front end of the movable impact head 130 and the surface of the iron tower. During impact, the non-magnetic spacer is located between the movable impact head 130 and the surface of the iron tower to prevent the magnetic field generated by the electromagnetic coil 120 when it is energized from adsorbing the movable impact head 130 on the surface of the iron tower. The non-magnetic spacer should be of sufficient thickness to block the attraction of the magnetic field without affecting the effective transmission of the impact force and the detection sensitivity. Optionally, the thickness of the non-magnetic spacer is 1-2 mm, which can effectively isolate the magnetic field and prevent the movable impact head 130 from being adsorbed by the iron tower after the impact, while not significantly weakening the energy transmitted by the impact. A non-magnetic spacer that is too thin will result in insufficient magnetic field shielding effect and will not be able to completely avoid the adsorption of the movable impact head 130. A non-magnetic spacer that is too thick will increase the distance between the movable impact head 130 and the iron tower structure, thereby weakening the effect of the impact force transmission and affecting the detection accuracy.

[0029] In this embodiment, a piezoelectric acceleration sensor 200 is used as a sensor for detecting vibration signals. The piezoelectric acceleration sensor 200 can provide high-sensitivity signal detection in a vibration environment, and is particularly suitable for detecting smaller vibrations and shock waves, which is particularly critical when judging the loose state of the transmission tower bolts, because the vibration signal caused by the loose bolts is usually weak, requiring the sensor to accurately capture and transmit these signals. In addition, the piezoelectric acceleration sensor 200 has an extremely fast response speed and can detect transient vibrations and shocks in real time. This feature is very suitable for the detection of impact elastic waves in this application, because the time span of this waveform is short and the signal transmission is rapid, and the rapid response capability of the sensor helps to improve the accuracy and reliability of the detection. In addition, the piezoelectric acceleration sensor 200 has a wide frequency response range and can effectively detect low-frequency and high-frequency vibration signals. In the detection of transmission tower bolts, the impact elastic wave may involve components of different frequencies, and the piezoelectric acceleration sensor 200 can fully capture these frequency changes, thereby providing a more comprehensive signal analysis. In this embodiment, optionally, the piezoelectric acceleration sensor 200 uses a PZT (lead zirconate titanate) piezoelectric ceramic sensor. This type of sensor has high sensitivity and reliable charge output and is widely used in vibration detection applications.

[0030] In some embodiments, Figure 2-Figure 4 As shown, a supporting device 600 is provided at the bottom end of the electromagnetic shock excitation device 100 , and the supporting device 600 includes a support 610 with a magnetic attraction function, a retractable connecting sleeve 620 and an angle adjustment mechanism 630 that can adjust the tilt angle of the electromagnetic shock excitation device 100 .

[0031] like Figure 2 As shown, a plurality of groups of neodymium magnets are embedded at the bottom end of the support 610, and a connecting sleeve 620 is fixedly connected to the support 610. Optionally, the connecting sleeve 620 is formed by sleeves and connecting rods in the sleeves. The connecting sleeve 620 has an adjusting knob 621 for locking the position after the connecting sleeve 620 is telescopically adjusted. Figure 2 and Figure 3 As shown, the other end of the connecting sleeve 620 is provided with an angle adjustment mechanism 630, and a connecting plate 640 with a connecting ring 641 is connected to the angle adjustment mechanism 630, and a rubber pad 642 is pasted on the upper surface of the connecting plate 640, and the connecting plate 640 is connected to the bottom end of the electromagnetic shock excitation device 100 by four bolts, and the rubber pad 642 is located between the connecting plate 640 and the bottom end of the electromagnetic shock excitation device 100; The signal acquisition module 300 , the signal processing unit 400 and the power control module 500 are all disposed inside the support 610 .

[0032] In this embodiment, the electromagnetic shock excitation device 100 is provided with a support 610 with a magnetic suction function, so that it can be firmly fixed on the surface of the tower structure, reducing the displacement and instability problems during operation, and improving the accuracy and stability during shock excitation. In this embodiment, an angle adjustment mechanism 630 is provided on the connecting sleeve 620, and the electromagnetic shock excitation device 100 is connected through the angle adjustment mechanism 630. When in use, the angle adjustment mechanism 630 allows the electromagnetic shock excitation device 100 to adjust its tilt angle, so that it can be flexibly arranged in a complex tower structure, so that the electromagnetic shock excitation device 100 can be positioned according to actual conditions, and the adaptability of the detection system in different use environments is improved. In addition, a rubber pad 642 is provided between the connecting plate 640 and the bottom end of the electromagnetic shock excitation device 100, which can absorb the micro-vibration generated during the impact, protect the overall structure of the device, extend its service life, and reduce the error caused by the impact.

[0033] In some embodiments, a protective shell 210 is provided at the top of the piezoelectric acceleration sensor 200, and connection holes 211 are respectively opened on the left and right sides of the protective shell 210. The protective shell 210 is connected to a bracket 212 located on the outside of the piezoelectric acceleration sensor 200 through the two connection holes 211, and the lower ends of the bracket 212 are respectively connected to spring clips 213 for fixing the bracket 212 on the iron tower structure, so that the piezoelectric acceleration sensor 200 can be fixed.

[0034] In this embodiment, a protective shell 210 is provided at the top of the piezoelectric acceleration sensor 200. The protective shell 210 can protect the piezoelectric acceleration sensor 200 and avoid direct damage to it from the external environment, such as rain, dust and mechanical collision, thereby improving the durability of the device in the outdoor environment. In addition, the protective shell 210 is provided with a connection hole 211 and a bracket 212, so that the piezoelectric acceleration sensor 200 can be stably installed on the tower structure, so that it can maintain stable contact when collecting vibration signals, thereby improving the accuracy of signal reception. Moreover, the spring clips 213 at both ends below the bracket 212 provide the ability to quickly install and disassemble, so that the piezoelectric acceleration sensor 200 can be easily adjusted and maintained, thereby enhancing the flexibility and convenience of use.

[0035] Furthermore, the connection hole 211 is a threaded connection hole, such as Figure 6 As shown, the bracket 212 is composed of a first connecting rod and a second connecting rod located on the left and right sides of the protective shell 210. Figure 6 and Figure 7 As shown, the first connecting rod and the second connecting rod each include a threaded connecting rod 2121 , an L-shaped transition rod 2122 , a vertical spring 2123 and a vertical connecting rod 2124 .

[0036] The threaded connecting rod 2121, the L-shaped transition rod 2122, the vertical spring 2123 and the vertical connecting rod 2124 are connected in sequence, one end of the threaded connecting rod 2121 is threadedly connected to the connecting hole 211, the other end of the threaded connecting rod 2121 is rotatably connected to the L-shaped transition rod 2122, the other end of the L-shaped transition rod 2122 is fixedly connected to the vertical spring 2123 and is connected to the vertical connecting rod 2124 through the vertical spring 2123, and the end of the vertical connecting rod 2124 is connected to the spring clip 213.

[0037] A plurality of cable guide clamps 21241 are provided on the rod body of the vertical connecting rod 2124, and the guide clamps 21241 are C-shaped clamps with openings.

[0038] The bracket 212 used in this embodiment adopts an adjustable bracket structure. The design of the bracket 212 includes a threaded connecting rod 2121, an L-shaped transition rod 2122 and a vertical spring 2123, so that the width and height of the bracket 212 are adjustable, so that it can adapt to different tower structures and improve the adaptability of the installation of the piezoelectric acceleration sensor 200. The introduction of the vertical spring 2123 provides buffer protection for the piezoelectric acceleration sensor 200, reduces the impact of external vibration on the sensor, and ensures the stability and accuracy of the detection. In addition, the cable guide clamp 21241 on the vertical connecting rod 2124 helps to fix and guide the connecting cable, reduces external interference and friction damage of the cable, and can improve the safety and service life of the system.

[0039] In some embodiments, Figure 4 and Figure 5 As shown, the spring guide mechanism 140 includes a guide rod 141, a compression spring 142 and a guide tube 143, and the fixed base 150 is connected to the rear end of the shell 110. In this embodiment, optionally, the fixed base 150 is threadedly connected to the outer side of the bottom end of the shell 110, and the fixed base 150 is provided with a guide tube 143 located in the shell 110. The guide rod 141 is arranged in the guide tube 143 and slidably cooperates with the guide tube 143. The front end of the guide rod 141 is connected to the rear end of the movable impact head 130, and a compression spring 142 is also connected between the rear end of the movable impact head 130 and the front end of the guide tube 143.

[0040] The spring guide mechanism 140 used in this embodiment can provide stable guidance for the movable impact head 130 during movement, wherein the spring guide mechanism 140 enables the movable impact head 130 to maintain stable axial movement during impact through the sliding cooperation of the guide rod 141 and the guide tube 143, thereby reducing the offset and angle errors and improving the accuracy of the impact. Moreover, the setting of the compression spring 142 provides a return force to ensure that the movable impact head 130 can quickly return to its initial position after each impact, thereby improving the working efficiency and reliability of the detection system. In addition, this embodiment combines the spring guide mechanism 140 with the fixed base 150, and sets the spring guide mechanism 140 on the fixed base 150 through the guide tube 143, which helps to make the overall structure compact and can improve the overall mechanical stability of the device.

[0041] During use, when the electromagnetic coil 120 is energized, an axial magnetic field is formed inside the electromagnetic coil 120 in the housing 110. Since the movable impact head 130 is made of ferromagnetic material, it is located in the central area of ​​the electromagnetic coil 120. Under the action of the magnetic field, the movable impact head 130 will be driven by the electromagnetic force, accelerate forward, generate impact force and contact with the outside through the impact port, thereby completing the impact action. The spring guide mechanism 140 includes a guide rod 141, a compression spring 142 and a guide tube 143, which ensure that the movable impact head 130 can be quickly reset after completing the forward impact. When the electromagnetic coil 120 is powered off, the drive of the electromagnetic force is lost, and the compression spring 142 will release its own elastic potential energy to push the movable impact head 130 back to the initial position, thereby achieving the reset of the movable impact head 130. The alternating process of energizing and de-energizing the electromagnetic coil 120 causes the impact head to perform a periodic motion of forward impact and return under the interaction of electromagnetic force and spring force. This design enables the movable impact head 130 to perform reciprocating impact under the control of the system, thereby generating a stable impact elastic wave.

[0042] In some embodiments, Figure 1 and Figure 8 As shown, the power control module 500 includes a power output interface 510, a power control unit 520, a power indicator light 530, an input power interface 540, an adjustment knob 550 and a BNC interface 560; The power output interface 510 is used to connect to the electromagnetic shock excitation device 100, the signal acquisition module 300, the signal processing unit 400 and the power control module 500 respectively, and is used to provide stable power; The power control unit 520 uses a pulse width modulation (PWM) controller to adjust the pulse frequency and pulse width of the output current according to the setting of the adjustment knob 550 to control the impact frequency and strength of the electromagnetic impact excitation device 100. During use, the pulse width modulation (PWM) controller can be used to adjust the pulse frequency and pulse width of the electromagnetic coil 120. The pulse width modulation (PWM) controller controls the on and off of the current through a fast switch, so that the electromagnetic coil 120 generates a pulse current within a set time period, thereby forming an intermittent electromagnetic force to drive the impact head to perform periodic motion. Under the control of the PWM controller, the electromagnetic coil 120 forms an electromagnetic field during the "power-on" pulse. The attraction generated by this electromagnetic field pushes the movable impact head 130 to accelerate forward and complete the impact action. When the PWM controller enters the "power-off" pulse, the current of the electromagnetic coil 120 is interrupted and the electromagnetic force disappears. At this time, the spring guide mechanism 140 releases its stored elastic potential energy, pushes the movable impact head 130 back to the initial position, and completes the return action. When in use, the PWM controller switches the current at a set frequency, causing the electromagnetic coil to be energized and de-energized periodically. The higher the frequency, the more times the impact head reciprocates. The impact force is determined by the pulse width. A longer pulse width (longer current conduction time) will cause the electromagnetic coil 120 to generate a stronger electromagnetic force during the power-on period, pushing the movable impact head 130 to impact with greater force, while a shorter pulse width will produce a smaller impact force. By adjusting the parameters of the PWM controller in this embodiment, the user can adjust the frequency and force of the impact head according to different detection requirements, thereby adapting to different detection environments and requirements.

[0043] A power indicator light 530, used to display the working status of the power control module 500; An input power interface 540, used to connect to an external power source for power supply; The adjustment knob 550 is used to manually adjust the pulse frequency and pulse width of the power control unit 520; The power output interface 510, the power indicator light 530, the input power interface 540 and the adjustment knob 550 are respectively arranged on the support 610, and the power control unit 520 is arranged inside the support 610; the power output interface 510 is connected to the electromagnetic shock excitation device 100 and the signal acquisition module 300 through a shielded cable, and the piezoelectric acceleration sensor 200 and the signal acquisition module 300 as well as the signal acquisition module 300 and the signal processing unit 400 are respectively connected by shielded cables; the support 610 is also provided with a BNC interface 560 for connecting the piezoelectric acceleration sensor 200 and the signal acquisition module 300 through a shielded cable.

[0044] In this embodiment, the power control module 500 adopts a design including a power output interface 510, a power control unit 520, a power indicator light 530, an input power interface 540, an adjustment knob 550 and a BNC interface 560, which can provide stable power support to maintain stable power supply during use and avoid the decrease in detection accuracy caused by power fluctuations. The power control unit 520 adopts a pulse width modulation controller, and the pulse frequency and width can be set by adjusting the knob 550 during use, so as to adjust the impact frequency and strength of the impact excitation device 100, so that the system is more adaptable under different working conditions and can flexibly respond to various detection requirements. Moreover, this embodiment reasonably arranges the various components of the power control module 500 on the support 610, which can improve the integration of the system and make the overall structure more compact, thereby facilitating deployment during use.

[0045] Alternatively, if Figure 2 and Figure 3 As shown, the angle adjustment mechanism 630 includes a rotating support 631, a connecting shaft 632 and a locking knob 633. The rotating support 631 is connected to the end of the connecting sleeve 620 away from the support 610. The rotating support 631 is a cylindrical structure adapted to the connecting ring 641. The middle part of the rotating support 631 is movably connected with a connecting shaft 632. Both ends of the connecting shaft 632 are respectively threadedly connected with locking knobs 633. The rotating support 631 is fixedly connected to the connecting ring 641, and the connecting ring 641 is fixedly connected to the connecting plate 640.

[0046] The angle adjustment mechanism 630 realizes multi-angle adjustment of the electromagnetic impact excitation device 100 through the rotating support 631 and the connecting shaft 632, which expands the operating range of the detection system and can meet the detection requirements of complex tower structures. When in use, the angle can be fixed by the locking knob 633, so that it can be quickly locked after the angle is adjusted, so that the angle can be kept stable during the detection process and not easily shifted, thereby improving the accuracy of the detection. The angle adjustment mechanism 630 used in this embodiment is reasonably designed and simple to operate. It can achieve adjustment without the need for additional complex tools, which provides convenience for on-site operation.

[0047] In some embodiments, Fig. 9 As shown, the signal processing unit 400 includes a signal amplifier 410 , a filter 420 , an analog-to-digital converter 430 , and a digital signal processor 440 .

[0048] The signal amplifier 410 is connected to the signal acquisition module 300 and is used to amplify the received vibration signal, thereby increasing the strength of the vibration signal so that weak signals can also be effectively detected, thereby improving the sensitivity of the overall system.

[0049] The filter 420 is connected to the output end of the signal amplifier 410 and is used to remove noise from the amplified signal and extract the signal within the target frequency range, thereby ensuring that the processed signal is purer and improving the accuracy of signal analysis.

[0050] an analog-to-digital converter 430 connected to the output end of the filter 420 and configured to convert the filtered analog vibration signal into a digital signal; The digital signal processor 440 is connected to the output end of the analog-to-digital converter 430 and is used to analyze the digitized vibration signal and extract waveform characteristic parameters to determine the loose state of the bolt. This embodiment realizes the conversion and analysis from analog signals to digital signals through the cooperation of the analog-to-digital converter 430 and the digital signal processor 440, and can extract and analyze waveform characteristic parameters, thereby providing a more reliable judgment of the loose state of the bolt.

[0051] The method of using the transmission tower bolt loosening detection system based on impact elastic wave in the embodiment of the present application is as follows: 1. Equipment installation: The electromagnetic shock excitation device 100 is arranged just below or just above the bolt connection to be inspected of the transmission tower, and is ensured to be fixed in a suitable position so that the shock elastic wave can directly act on the bolt and the surrounding structure.

[0052] At the same time, the piezoelectric acceleration sensor 200 is installed on the surface of the tower structure no more than 10 cm away from the bolt to be detected, ensuring that the piezoelectric acceleration sensor 200 is in close contact with the surface of the structure to obtain a stable vibration signal. The electromagnetic shock excitation device 100 is fixed and supported by the support device 600 to ensure its stable position, and the angle of the device is adjusted by the angle adjustment mechanism 630 to align it with the detection position.

[0053] 2. System connection: The piezoelectric acceleration sensor 200 is connected to the signal acquisition module 300 through a shielded cable to reduce external electromagnetic interference. At the same time, the signal acquisition module 300 is connected to the signal processing unit 400 and ensures that the power control module 500 provides stable power support through the cable.

[0054] 3. Detection operation: The power control module 500 is started, and the frequency and width of the current are adjusted by the pulse width modulation controller to excite the electromagnetic coil (120) in the electromagnetic shock excitation device 100 to generate an axial magnetic field. The electromagnetic coil 120 drives the movable impact head 130 to move along the guide structure in the shell 110 and impact the surface of the tower structure to generate impact elastic waves. The shock wave propagates through the bolts and the surrounding structure, causing vibration.

[0055] 4. Signal acquisition and processing: The piezoelectric acceleration sensor 200 receives the vibration signal caused by the impact elastic wave, converts it into an electrical signal, and transmits it to the signal acquisition module 300 for preliminary amplification; the amplified signal is transmitted to the signal processing unit 400, and the signal strength is further enhanced by the signal amplifier 410. After the filter 420 removes the noise, the analog-to-digital converter 430 converts the analog signal into a digital signal. The digital signal processor 440 analyzes the digital signal and extracts the main frequency, amplitude and envelope characteristic parameters to determine the loose state of the bolt.

[0056] The embodiment of the present application further provides a method for detecting loose bolts of a transmission tower based on impact elastic waves, which uses the transmission tower bolt loosening detection system based on impact elastic waves provided in the embodiment of the present application to perform bolt loosening detection on the transmission tower, specifically comprising the following steps: Step 1: Install the electromagnetic shock excitation device 100 just below or just above the bolt connection of the transmission tower, and provide a pulse current to the electromagnetic shock excitation device 100 through the power control module 500 to drive the movable impact head 130 to generate impact elastic waves; Step 2: transmitting the impact elastic wave to the bolt and its surrounding structure through the movable impact head 130, causing vibration in the bolt area; Step 3: a piezoelectric acceleration sensor 200 is arranged at a position no more than 10 cm away from the bolt to be detected, in contact with the tower structure, to collect vibration signals caused by elastic waves; Step 4: Transmit the collected vibration signal to the signal acquisition module 300 through a shielded cable for signal amplification; Step 5: Transmit the amplified signal to the signal processing unit 400 to analyze and extract the signal characteristic parameters to determine whether the bolt is loose.

[0057] The transmission tower bolt loosening detection method based on impact elastic wave provided in this embodiment adopts the transmission tower bolt loosening detection system based on impact elastic wave provided in this application. Through such a detection method, the operation process can be standardized and repeatable, thereby helping technicians to quickly perform detection on site, and improving the efficiency and consistency of the detection work. The detection method optimizes the signal transmission path by setting the electromagnetic impact excitation device 100 at the bolt connection and generating impact elastic wave, and then collecting the vibration signal by the piezoelectric acceleration sensor 200, so as to enable the vibration signal to be efficiently received and analyzed, thereby effectively solving the problem of insufficient signal coupling existing in the existing detection equipment. This embodiment combines the stable power supply of the power control module 500 and the use of shielded cables, can ensure the stability of the whole process from signal generation to processing, and has good anti-interference ability, so that the detection system can maintain good performance in various environments, thereby improving the reliability and accuracy of the detection results.

[0058] Optionally, in step 1, the frequency and pulse width of the pulse current are adjusted by the pulse width modulation controller in the power control module 500 to control the impact frequency and force of the movable impact head 130; in step 5, the signal characteristic parameters extracted by the signal processing unit 400 include the main frequency, amplitude and envelope characteristic parameters.

[0059] In this embodiment, the pulse frequency and width of the current are adjusted by the pulse width modulation controller in the power control module 500, so that the impact frequency and strength of the electromagnetic impact excitation device can be adjusted. This function realizes the flexible adjustment of the detection conditions, and can be optimally set according to different bolts and tower structures, thereby improving the adaptability of the detection. In the signal processing unit 400, the method of extracting the main frequency, amplitude and envelope characteristic parameters helps to comprehensively judge the loose state of the bolt. This multi-dimensional feature extraction scheme helps to enhance the accuracy of the judgment result and avoids the misjudgment that may be caused by a single parameter. The detection method given in the embodiment of the present application can make the vibration signal maintain good consistency and integrity during the collection and analysis process. Through signal amplification, denoising, analog-to-digital conversion and digital signal processing, the detection system can make an accurate analysis of the loose state of the bolt, thereby solving the key problems of signal distortion and instability in the prior art.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A transmission tower bolt loosening detection system based on impact elastic wave, characterized in that: It comprises an electromagnetic shock excitation device (100), a piezoelectric acceleration sensor (200), a signal acquisition module (300), a signal processing unit (400) and a power supply control module (500); The electromagnetic shock excitation device (100) is arranged directly below or directly above the bolt connection of the transmission iron tower, and is used to couple the elastic wave generated by the shock to the bolt and the structure around the bolt to cause vibration; the piezoelectric acceleration sensor (200) is arranged on the surface of the iron tower structure no more than 10 cm away from the bolt to be detected and is in contact with the surface of the iron tower structure, and is used to receive the vibration signal caused by the electromagnetic shock excitation device (100); the signal acquisition module (300) is connected to the piezoelectric acceleration sensor (200) through a cable, and is used to receive and amplify the vibration signal collected by the piezoelectric acceleration sensor (200); the signal processing unit (400) is connected to the signal acquisition module (300) through a cable, and is used to analyze the received vibration signal to determine the loose state of the bolt; the power control module (500) is respectively connected to the electromagnetic shock excitation device (100), the signal acquisition module (300) and the signal processing unit (400) through cables, and is used to provide power support; The electromagnetic impact excitation device (100) comprises a housing (110), an electromagnetic coil (120), a movable impact head (130), a spring guide mechanism (140) and a fixed base (150); the electromagnetic coil (120) is installed in the middle of the housing (110); the electromagnetic coil (120) is wound into a spiral structure and can form an axial magnetic field in the housing (110) after being energized; an impact opening is provided at the end of the housing (110) for the movable impact head (130) to extend out; the movable impact head (130) is made of ferromagnetic material, is located in the central area of ​​the electromagnetic coil (120) and has its front end facing the impact opening of the housing (110); the rear end of the movable impact head (130) is connected to the spring guide mechanism (140); and the fixed base (150) is arranged at the bottom end of the housing (110).

2. The transmission tower bolt loosening detection system based on impact elastic wave according to claim 1 is characterized in that: A supporting device (600) is provided at the bottom end of the electromagnetic shock excitation device (100), the supporting device (600) comprising a support (610) with a magnetic attraction function, a retractable connecting sleeve (620), and an angle adjustment mechanism (630) capable of adjusting the tilt angle of the electromagnetic shock excitation device (100); A plurality of groups of neodymium magnets are embedded at the bottom end of the support (610); the connection sleeve (620) is fixedly connected to the support (610); the angle adjustment mechanism (630) is provided at the other end of the connection sleeve (620); a connection plate (640) having a connection ring (641) is connected to the angle adjustment mechanism (630); a rubber pad (642) is adhered to the upper surface of the connection plate (640); the connection plate (640) and the bottom end of the electromagnetic shock excitation device (100) are connected by four bolts; and the rubber pad (642) is located between the connection plate (640) and the bottom end of the electromagnetic shock excitation device (100); The signal acquisition module (300), the signal processing unit (400) and the power control module (500) are all arranged inside the support (610).

3. The transmission tower bolt loosening detection system based on impact elastic wave according to claim 1 or 2, characterized in that: A protective shell (210) is provided at the top of the piezoelectric acceleration sensor (200), and connection holes (211) are respectively provided on the left and right sides of the protective shell (210), and the protective shell (210) is connected to a bracket (212) located outside the piezoelectric acceleration sensor (200) through the two connection holes (211), and spring clips (213) for fixing the bracket (212) on an iron tower structure are respectively connected to the lower ends of the bracket (212), so that the piezoelectric acceleration sensor (200) can be fixed.

4. The transmission tower bolt loosening detection system based on impact elastic wave according to claim 3 is characterized in that: The connection hole (211) is a threaded connection hole, and the bracket (212) is composed of a first connection rod and a second connection rod located on the left and right sides of the protective shell (210), and the first connection rod and the second connection rod both include a threaded connecting rod (2121), an L-shaped transition rod (2122), a vertical spring (2123) and a vertical connecting rod (2124); The threaded connecting rod (2121), the L-shaped transition rod (2122), the vertical spring (2123) and the vertical connecting rod (2124) are connected in sequence; one end of the threaded connecting rod (2121) is threadedly connected to the connecting hole (211); the other end of the threaded connecting rod (2121) is rotatably connected to the L-shaped transition rod (2122); the other end of the L-shaped transition rod (2122) is fixedly connected to the vertical spring (2123) and is connected to the vertical connecting rod (2124) via the vertical spring (2123); and the end of the vertical connecting rod (2124) is connected to the spring clip (213); A plurality of cable guide clamps (21241) are provided on the rod body of the vertical connecting rod (2124), and the guide clamps (21241) are C-shaped clamps with openings.

5. The transmission tower bolt loosening detection system based on impact elastic wave according to claim 1 is characterized in that: The spring guide mechanism (140) comprises a guide rod (141), a compression spring (142) and a guide tube (143); the fixed base (150) is connected to the rear end of the housing (110); the fixed base (150) is provided with the guide tube (143) located in the housing (110); the guide rod (141) is arranged in the guide tube (143) and slidably cooperates with the guide tube (143); the front end of the guide rod (141) is connected to the rear end of the movable impact head (130); and the compression spring (142) is also connected between the rear end of the movable impact head (130) and the front end of the guide tube (143).

6. The transmission tower bolt loosening detection system based on impact elastic wave according to claim 2 is characterized in that: The power control module (500) comprises a power output interface (510), a power control unit (520), a power indicator light (530), an input power interface (540), an adjustment knob (550) and a BNC interface (560); The power output interface (510) is used to be connected to the electromagnetic shock excitation device (100), the signal acquisition module (300), the signal processing unit (400) and the power control module (500) respectively, and is used to provide stable power; The power control unit (520) adopts a pulse width modulation controller, which is used to adjust the pulse frequency and pulse width of the output current according to the setting of the adjustment knob (550) to control the impact frequency and strength of the electromagnetic impact excitation device (100); The power indicator light (530) is used to display the working state of the power control module (500); The input power interface (540) is used to connect to an external power source for power supply; The adjusting knob (550) is used to manually adjust the pulse frequency and pulse width of the power control unit (520); The power output interface (510), the power indicator light (530), the input power interface (540) and the adjustment knob (550) are respectively arranged on the support (610), and the power control unit (520) is arranged inside the support (610); the power output interface (510) is connected to the electromagnetic shock excitation device (100) and the signal acquisition module (300) through a shielded cable, and the piezoelectric acceleration sensor (200) and the signal acquisition module (300) as well as the signal acquisition module (300) and the signal processing unit (400) are respectively connected through shielded cables; The support (610) is also provided with the BNC interface (560) for connecting the piezoelectric acceleration sensor (200) and the signal acquisition module (300) via a shielded cable.

7. The transmission tower bolt loosening detection system based on impact elastic wave according to claim 2 is characterized in that: The angle adjustment mechanism (630) comprises a rotating support (631), a connecting shaft (632) and a locking knob (633); the rotating support (631) is connected to one end of the connecting sleeve (620) away from the support (610); the rotating support (631) is a cylindrical structure adapted to the connecting ring (641); the connecting shaft (632) is movably connected to the middle of the rotating support (631); the locking knob (633) is respectively threadedly connected to both ends of the connecting shaft (632); the rotating support (631) is fixedly connected to the connecting ring (641); and the connecting ring (641) is fixedly connected to the connecting plate (640).

8. The transmission tower bolt loosening detection system based on impact elastic wave according to claim 1 or 6, characterized in that: The signal processing unit (400) comprises a signal amplifier (410), a filter (420), an analog-to-digital converter (430) and a digital signal processor (440); The signal amplifier (410) is connected to the signal acquisition module (300) and is used to amplify the received vibration signal; The filter (420) is connected to the output end of the signal amplifier (410) and is used to remove noise from the amplified signal and extract the signal within the target frequency range; The analog-to-digital converter (430) is connected to the output end of the filter (420) and is used to convert the filtered analog vibration signal into a digital signal; The digital signal processor (440) is connected to the output end of the analog-to-digital converter (430) and is used to analyze the digitized vibration signal and extract waveform characteristic parameters to determine the loose state of the bolt.

9. A method for detecting loose bolts of a transmission tower based on impact elastic waves, characterized in that: The transmission tower bolt loosening detection system based on impact elastic wave according to any one of claims 1 to 8 comprises the following steps: Step 1: installing an electromagnetic shock excitation device (100) directly below or directly above a bolt connection of a transmission tower, and providing a pulse current to the electromagnetic shock excitation device (100) through a power control module (500) to drive a movable impact head (130) to generate an impact elastic wave; Step 2: transmitting the impact elastic wave to the bolt and its surrounding structure through the movable impact head (130), causing vibration in the bolt area; Step 3: a piezoelectric acceleration sensor (200) is arranged at a position no more than 10 cm away from the bolt to be detected, in contact with the tower structure, to collect vibration signals caused by elastic waves; Step 4: transmitting the collected vibration signal to the signal collection module (300) via a shielded cable for signal amplification; Step 5: Transmit the amplified signal to the signal processing unit (400), analyze and extract the signal characteristic parameters to determine whether the bolt is loose.

10. The method for detecting loose bolts of a transmission tower based on impact elastic waves according to claim 9, characterized in that: In step 1, the frequency and pulse width of the pulse current are adjusted by a pulse width modulation controller in a power control module (500) to control the impact frequency and strength of the movable impact head (130); In step 5, the signal characteristic parameters extracted by the signal processing unit (400) include main frequency, amplitude and envelope characteristic parameters.

Images