Triboelectric displacement sensor with ultrahigh resolution and crack monitoring system

Abstract

The invention provides a triboelectric displacement sensor with ultrahigh resolution and a crack monitoring system. The sensor comprises a base, a rack, a rack connecting seat, a gear, a planetary gear accelerator, a fixed end cover, a rotor assembly and a stator assembly. Through a gear and rack transmission mode, rotation speed amplification of a planetary gear accelerator and a multi-phase special electrode arrangement mode, tiny displacement changes of crack cracking are converted into electric signal output, and a crack monitoring system is developed through signal processing and digital-to-analog conversion; and the visual real-time monitoring of the crack displacement width and speed is realized. Compared with the prior art, the method has the advantages of high resolution, high-precision monitoring, low cost and no use space limitation.

Description

Technical Field

[0001] The invention relates to a triboelectric displacement sensor with ultra-high resolution and a crack monitoring system, belonging to the technical field of intelligent monitoring. Background Art

[0002] Concrete structures, such as bridges, tunnels and large buildings, play a vital role in modern infrastructure. However, due to its high brittleness and poor toughness, it is very easy to crack under external loads (fatigue stress, temperature stress, shrinkage stress, etc.). If concrete cracks are not detected and treated in time, they may cause serious structural damage. Therefore, effective monitoring of concrete cracks is essential to ensure the safety and life of these critical structures.

[0003] Traditional methods such as visual inspection and manual measurement are labor-intensive and subjective, making them unreliable in detecting small crack width changes. Advanced technologies such as fiber optic sensors and ultrasonic testing offer greater accuracy but still face challenges such as high cost, complexity, and the need for specialized equipment.

[0004] As a promising alternative, triboelectric sensors have attracted attention due to their high sensitivity, low cost, and easy integration into existing structures. These sensors work on the principle that mechanical deformation generates electrical signals that can be correlated with the movement of cracks. However, the resolution of current triboelectric sensors for concrete crack monitoring is relatively low. Although the resolution can be improved by subdividing the electrodes, it is still low due to the limitations of practical manufacturing technology.

[0005] Therefore, there is an urgent need to explore a triboelectric displacement sensor with ultra-high resolution based on the principle of friction nanogenerator to monitor the expansion changes of cracks in concrete structures. Summary of the invention

[0006] Purpose of the invention: The present invention proposes an ultra-high-resolution triboelectric displacement sensor and a crack monitoring system to achieve high-resolution and high-precision monitoring of cracks. The monitoring method is low-cost and not limited by the use space.

[0007] Technical solution: The present invention describes a triboelectric displacement sensor with ultra-high resolution, a triboelectric displacement sensor with ultra-high resolution, the sensor comprising a base, a rack, a rack connecting seat, a gear, a planetary gear accelerator, a fixed end cover, a rotor assembly and a stator assembly; the base is fixed on one side of the crack, the rack connecting seat is fixed on the other side of the crack, the rack connecting seat is slidably installed in the first slide groove on the base, and the base and the rack connecting seat are slidably connected; the rack and the rack connecting seat are fixedly connected; the rack is meshed with the gear, and the gear and the input shaft of the planetary gear accelerator are fixedly connected; the planetary gear accelerator is fixed to the base by the fixed end cover; the rotor assembly is fixed on the output shaft of the planetary gear accelerator; the stator assembly is fixed to the base.

[0008] Furthermore, the rotor assembly includes a rotor fixing frame, a rotor electrode plate and a friction film; the rotor fixing frame is fixedly connected to the output shaft of the planetary gear accelerator; the rotor electrode plate is fixedly connected to the rotor fixing frame; and the friction film is fixed on the rotor electrode.

[0009] Furthermore, the stator assembly includes a stator fixing frame and a stator electrode plate, the stator fixing frame is fixed on the base, the stator electrode plate is fixed on the stator fixing frame, and the stator electrode plate is in contact with the friction film.

[0010] Furthermore, the stator electrode plate attached electrode adopts an annular interdigitated electrode, which is arranged periodically with m phases, m>1, and θ is defined as the sum of the angle of the stator attached annular electrode and the electrode gap angle. The angle of the stator electrode plate attached annular electrode is 5θ / 6, and the electrode gap is θ / 6; the angle of the rotor electrode plate attached annular electrode is equal to 5θ / 6, and the angle between the rotor attached annular electrodes is θ+θ / m.

[0011] Furthermore, the attached electrodes on the rotor electrode plate and the stator electrode plate are made of conductive materials; and the friction film is made of a polymer material having a friction electrification effect.

[0012] Furthermore, the calculation formula for the resolution of the triboelectric displacement sensor is π*d / i*m*p v , where i is the transmission ratio, d is the gear diameter, and p is v is the number of annular electrodes attached to the rotor. When the gear diameter and the number of annular electrodes attached to the rotor are constant, the comprehensive resolution is improved by a factor of i*m.

[0013] A real-time crack monitoring system with an ultra-high-resolution triboelectric displacement sensor, the real-time monitoring system comprising a triboelectric displacement sensor, a voltage amplifier, a voltage hysteresis comparator, a single-chip microcomputer and a display screen; the voltage amplifier is used to amplify the electrical signal output by the sensor, the voltage hysteresis comparator is used to convert the amplified analog signal into a digital signal, the single-chip microcomputer is used to filter the digital signal, extract the pulse frequency, extract the pulse amplitude and calculate the number of pulses, and the display screen is used to display the cracking displacement and speed in real time.

[0014] Compared with the prior art, the invention has the following beneficial effects: the invention proposes an ultra-high-resolution triboelectric displacement sensor and crack monitoring system, which converts the tiny displacement changes of crack opening into the output of electrical signals through the transmission mode of gear rack, the speed amplification of the planetary gear accelerator, and the special multi-phase electrode arrangement mode, and develops a crack monitoring system through signal processing and digital-to-analog conversion, realizing the visual real-time monitoring of the displacement width and speed of crack opening. It has the advantages of high-resolution and high-precision monitoring, and the monitoring method has the advantages of low cost and no limitation on the use space. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the overall structure of the triboelectric sensor with ultra-high resolution.

[0016] Figure 2 Schematic diagram of the rotor assembly of the triboelectric sensor with ultra-high resolution.

[0017] Figure 3 Schematic diagram of the stator assembly of a triboelectric sensor with ultra-high resolution.

[0018] Figure 4 Schematic diagram of the electrode arrangement of a triboelectric sensor with ultra-high resolution; (a) is the rotor electrode and (b) is the stator electrode.

[0019] Figure 5 This is the flow chart of the real-time monitoring system for concrete structure cracks based on ultra-high resolution triboelectric sensors. DETAILED DESCRIPTION

[0020] The following detailed description and drawings of the embodiments of the present invention are used to illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the described embodiments.

[0021] Specific implementation method 1: Combination Figure 1 to Figure 3 This embodiment describes a specific embodiment of an ultra-high resolution triboelectric displacement sensor. The specific embodiment is described as follows:

[0022] The ultra-high resolution triboelectric displacement sensor comprises a base 1, a rack 2, a rack connection seat 3, a gear 4, a planetary gear accelerator 5, a fixed end cover 6, a rotor assembly 7 and a stator assembly 8. The base 1 is fixed on one side of the crack by expansion bolts, the rack connection seat 3 is fixed on the other side of the crack by expansion bolts, the rack connection seat 3 is slidably installed in the first slide groove on the base 1, and the base 1 and the rack connection seat 3 are slidably connected; the rack 2 and the rack connection seat 3 are fixedly connected by bolts; the rack 2 is meshed with the gear 4, and the gear 4 and the D-type input shaft of the planetary gear accelerator 5 are interference connected (i.e. fixed); the planetary gear accelerator 5 is fixed to the base 1 by bolts of the fixed end cover 6; the rotor assembly 7 is fixed to the D-type output shaft of the planetary gear accelerator 5 by interference connection; the stator assembly 8 is fixed in the stator moving groove of the base 1 by interference connection.

[0023] The rotor assembly 7 includes a rotor fixing frame 7-1, a rotor electrode plate 7-2 and a friction film 7-3; the rotor fixing frame 7-1 is interference-connected with the D-type output shaft of the planetary gear accelerator 5; the rotor electrode plate 7-2 is interference-connected with the rotor fixing frame 7-1; the friction film 7-3 is attached to the rotor electrode plate 7-2.

[0024] The stator assembly 8 includes a stator fixing frame 8-1 and a stator electrode plate 8-2. The stator fixing frame 8-1 is connected to the stator moving slot of the base 1 by interference fit, and the stator electrode plate 8-2 is connected to the stator fixing frame 8-1 by interference fit.

[0025] The working principle of the ultra-high resolution friction electric displacement sensor is as follows: the rotor electrode plate 7-2 and the stator electrode plate 8-2 are both PCB hard boards, and the friction film 7-3 is in contact with the stator electrode plate 8-2. When a crack occurs, the base 1 and the rack connecting seat 3 produce relative displacement, driving the rack 2 to produce linear displacement, thereby driving the gear 4 to rotate, which is converted into rotational motion by the gear 4, and then the planetary gear accelerator 5 amplifies the speed and drives the rotor assembly 7 to rotate. When the rotor assembly 7 rotates relative to the stator assembly 8, due to the different electronegativity of the material of the friction film 7-3 and the material of the stator electrode plate 8-2, when the two materials rub against each other, friction electrification and electrostatic induction occur, thereby generating an AC signal that can reflect the change in crack opening displacement.

[0026] Regarding power generation materials, the rotor electrode plate 7-2 and the stator electrode plate 8-2 are both PCB substrates, and the electrodes attached to the substrates are all conductive materials, such as copper, aluminum, etc. In this specific embodiment, the electrodes of the electrode plates are all made of copper material; the friction film 7-3 is a polymer material with a friction electrification effect, such as FEP (polyperfluoroethylene) film, PTFE (polytetrafluoroethylene) film, etc. In this specific embodiment, the friction film 7-3 is made of PTFE film.

[0027] Regarding the planetary gear accelerator, the function of the planetary gear accelerator is to amplify the speed. The larger the transmission ratio, the higher the speed amplification factor. It is the key to improving the resolution. Different transmission ratios can be selected according to the different monitoring accuracy requirements. The transmission ratio of the planetary gear accelerator is defined as i. In this specific implementation, i is equal to 100.

[0028] Specific implementation method 2: Combination Figure 4 This specific embodiment provides a specific embodiment of the arrangement of the rotor electrode plate 7-2 and the stator electrode plate 8-2. The arrangement of the flexible electrode plate is described as follows:

[0029] The stator electrode plate 8-2 attachment electrode adopts an annular interdigitated electrode, which can be arranged in an m-phase periodic arrangement, m>1, and θ is defined as the sum of the stator attachment annular electrode angle and the electrode gap angle. The angle of the annular electrode is 5θ / 6, and the electrode gap is θ / 6; the rotor electrode plate 7-2 attachment annular electrode angle is equal to 5θ / 6, and the angle between the rotor attachment annular electrodes is θ+θ / m.

[0030] In this specific implementation, m is 5. The electrode structure can be further explained as increasing the number of electrode phases can improve the resolution of the sensor, and electrode misalignment can cause a phase difference in the electrical signal, which not only improves the resolution but also ensures the stability of the sensor.

[0031] Regarding the electrode structure, the advantage of this electrode is that it can improve the resolution. Specifically, the more phases there are, the more pulse signals there are, that is, the higher the resolution is, which is another key to improving the resolution. In this specific embodiment, the resolution is calculated as π*d / i*m*p v , where d is the gear diameter, p v is the number of annular electrodes attached to the rotor. When both are constant, the comprehensive resolution is improved by i*m, which is equal to 100×5, which is equal to 500 times, and the resolution can reach 3.14um.

[0032] Specific real-time method three: combination Figure 5 This embodiment proposes a specific implementation of a crack real-time monitoring system with an ultra-high resolution triboelectric displacement sensor. The crack real-time monitoring system with an ultra-high resolution triboelectric displacement sensor is described as follows:

[0033] The real-time crack monitoring system includes a friction electric displacement sensor, a voltage hysteresis comparator, a voltage amplifier, a single-chip microcomputer and a display screen. The voltage amplifier is used to amplify the electrical signal output by the sensor, the voltage hysteresis comparator is used to convert the amplified analog signal into a digital signal, the single-chip microcomputer is used to filter the digital signal, extract the pulse frequency, extract the pulse amplitude and calculate the number of pulses, and the display screen is used to display the cracking displacement and speed in real time.

[0034] The working principle of the real-time crack monitoring system is that when the sensor is stimulated by the outside world, it generates a corresponding electrical signal. The electrical signal generated by the sensor is first amplified by a voltage method device, and then the amplified analog signal is converted into a digital signal through a voltage hysteresis comparator. The microcontroller processes the digital signal, including filtering, pulse frequency extraction and amplitude extraction, and obtains the crack width displacement and speed through pulse counting and derivation, and then connects to the display to display the displacement and speed in real time.

[0035] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and intent of the present invention.

Claims

1. A triboelectric displacement sensor with ultra-high resolution, characterized in that: The sensor includes a base, a rack, a rack connecting seat, a gear, a planetary gear accelerator, a fixed end cover, a rotor assembly and a stator assembly; the base is fixed on one side of the crack, the rack connecting seat is fixed on the other side of the crack, the rack connecting seat is slidably installed in a first slide groove on the base, and the base and the rack connecting seat are slidably connected; the rack and the rack connecting seat are fixedly connected; the rack is meshed with the gear, and the gear and the input shaft of the planetary gear accelerator are fixedly connected; the planetary gear accelerator is fixed to the base by the fixed end cover; the rotor assembly is fixed to the output shaft of the planetary gear accelerator; the stator assembly is fixed to the base.

2. The triboelectric displacement sensor with ultra-high resolution according to claim 1, characterized in that: The rotor assembly includes a rotor fixing frame, a rotor electrode plate and a friction film; the rotor fixing frame is fixedly connected to the output shaft of the planetary gear accelerator; The rotor electrode plate is fixedly connected to the rotor fixing frame; the friction film is fixed on the rotor electrode.

3. The triboelectric displacement sensor with ultra-high resolution according to claim 2, characterized in that: The stator assembly comprises a stator fixing frame and a stator electrode plate. The stator fixing frame is fixed on the base, the stator electrode plate is fixed on the stator fixing frame, and the stator electrode plate is in contact with the friction film.

4. The triboelectric displacement sensor with ultra-high resolution according to claim 1, characterized in that: The stator electrode plate attachment electrode adopts an annular interdigitated electrode, which is arranged periodically with m phases, m>1, and θ is defined as the sum of the angle of the stator attached annular electrode and the electrode gap angle. The angle of the stator electrode plate attached annular electrode is 5θ / 6, and the electrode gap is θ / 6; The angle between the rotor electrode plate and the annular electrode is equal to 5θ / 6, and the angle between the rotor-attached annular electrodes is θ+θ / m.

5. The triboelectric displacement sensor with ultra-high resolution according to claim 3, characterized in that: The attached electrodes on the rotor electrode plate and the stator electrode plate are made of conductive materials; the friction film is a polymer material with a friction electrification effect.

6. The triboelectric displacement sensor with ultra-high resolution according to claim 3, characterized in that: The calculation formula for the resolution of the triboelectric displacement sensor is π*d / i*m*pv, where i is the transmission ratio, d is the gear diameter, and pv is the number of annular electrodes attached to the rotor. When the gear diameter and the number of annular electrodes attached to the rotor are constant, the comprehensive resolution is increased by a factor of i*m.

7. A real-time crack monitoring system with an ultra-high resolution triboelectric displacement sensor, characterized in that: The real-time monitoring system includes a triboelectric displacement sensor, a voltage amplifier, a voltage hysteresis comparator, a single-chip microcomputer and a display screen; the voltage amplifier is used to amplify the electrical signal output by the sensor, the voltage hysteresis comparator is used to convert the amplified analog signal into a digital signal, the single-chip microcomputer is used to filter the digital signal, extract the pulse frequency, extract the pulse amplitude and calculate the number of pulses, and the display screen is used to display the cracking displacement and speed in real time.

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