A multifunctional integrated passive sensing node device for bridges

Abstract

The utility model discloses a kind of multifunctional integrated passive sensing node devices for bridge, through piezoelectric cantilever beam collection bridge environmental vibration energy, and in combination with super capacitor energy storage, completely get rid of the dependence on solar panel, battery or external wiring, realize energy self-sufficiency, integrate MEMS accelerometer, multifunctional vibrating reed unit, attitude sensor multiple sensing functions in a unified sealed shell, solve the possible power failure of battery in continuous rainy days, and battery life is limited, need to be replaced regularly, maintenance cost is high, a large number of cable and independent power supply unit lead to installation complex, reliability reduces, fault point increases, each monitoring point needs a complete set of power supply and acquisition equipment, total cost is high, when new monitoring point, need to repeat complex installation and wiring work.

Description

Technical Field

[0001] This utility model relates to the field of bridge health monitoring technology, specifically a multifunctional integrated passive sensing node device for bridges. Background Technology

[0002] Currently, bridge health monitoring systems typically employ multiple independent sensors, such as hydrostatic levels, vibrating wire sensors, vibration sensors, and GNSS receivers. These sensors usually require independent installation, independent power supply (e.g., solar panels and batteries), and independent wiring. This distributed system has the following drawbacks.

[0003] Batteries may lose power during continuous rainy days, and their lifespan is limited, requiring regular replacement, resulting in high maintenance costs. The large number of cables and independent power supply units lead to complex installation, reduced reliability, and increased failure points. Each monitoring point requires a complete set of power supply and data acquisition equipment, keeping the total cost high. When adding new monitoring points, complex installation and wiring work needs to be repeated.

[0004] Therefore, there is an urgent need to design a multifunctional integrated passive sensing node device for bridges that can solve the above problems. Utility Model Content

[0005] The purpose of this utility model is to provide a multifunctional integrated passive sensing node device for bridges. To achieve the above objective, this utility model provides the following technical solution:

[0006] A multifunctional integrated passive sensing node device for bridges includes a housing, a main control circuit board disposed inside the housing, a vibration energy harvesting module, a power management circuit, a sensing unit, a wireless communication module, and a signal processing and control module. The bottom of the housing is provided with a mounting flange for fixing to the bridge structure.

[0007] The output terminal of the vibration energy harvesting module is connected to the input terminal of the power management circuit. The output terminal of the power management circuit supplies power to the sensing unit, the wireless communication module, and the signal processing and control module. The signal processing and control module is connected to the sensing unit and the wireless communication module respectively.

[0008] Furthermore, the vibration energy harvesting module is a piezoelectric cantilever beam structure, including a metal substrate, a piezoelectric ceramic sheet attached to the metal substrate, and a counterweight at the free end of the metal substrate.

[0009] The above technical solution can efficiently convert the continuous mechanical vibration energy generated by vehicle traffic and wind load in the bridge environment into electrical energy, providing the most basic and reliable energy source for the entire node.

[0010] Furthermore, the power management circuit includes a rectifier unit, a voltage regulator unit, and an energy storage unit, wherein the energy storage unit is a supercapacitor;

[0011] The above technical solution can process the unstable alternating current generated by the piezoelectric cantilever beam and convert it into stable and reliable direct current. By utilizing the characteristics of supercapacitors, such as long cycle life, fast charging and discharging speed, and high power density, the weak and intermittent energy can be continuously accumulated, ultimately providing sufficient pulsed power for data acquisition and wireless transmission.

[0012] Furthermore, the sensing unit includes a MEMS accelerometer, a multifunctional vibrating string unit, and an attitude sensor. The MEMS accelerometer and attitude sensor are mounted on the main control circuit board. The multifunctional vibrating string unit includes a sealed metal cavity, which is rigidly bonded to the bridge structure with high-strength epoxy resin adhesive.

[0013] The metal cavity contains a pre-tensioned metal string and an excitation coil. The signal processing and control module is configured to: obtain strain value by applying a sweep frequency excitation to the excitation coil and detecting the resonant frequency of the metal string, and obtain ambient temperature value by measuring the resistance value of the excitation coil.

[0014] The above technical solution integrates the most critical multi-parameter sensors for monitoring bridge health, such as vibration, strain, temperature, and tilt angle, onto a unified housing and main board. By directly and rigidly attaching the vibrating wire unit sensing part to the bridge body, high sensitivity and accuracy of structural strain sensing are ensured.

[0015] Furthermore, the wireless communication module is a LoRa communication module or an NB-IoT communication module.

[0016] Furthermore, the resonant frequency of the vibration energy harvesting module is designed to be Hz-Hz;

[0017] The above technical solutions enable the natural frequency of the bridge to match the main environmental vibration frequency bands under various loads.

[0018] Compared with the prior art, the beneficial effects of this utility model are:

[0019] This invention utilizes a multifunctional integrated passive sensing node device for bridges, achieving the following effects: 1. By collecting environmental vibration energy of the bridge through a piezoelectric cantilever beam and combining it with supercapacitor energy storage, it completely eliminates the dependence on solar panels, batteries, or external wiring, achieving energy self-sufficiency; 2. By integrating multiple sensing functions such as MEMS accelerometers, multifunctional vibrating string units, and attitude sensors into a unified sealed housing, it achieves a high degree of hardware integration and synchronous data acquisition, avoiding the problems of complex installation and asynchronous data in traditional distributed systems. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0021] Figure 2 This is a schematic diagram of the overall structure of this utility model;

[0022] Figure 3 This is a schematic diagram of the main control circuit board of this utility model;

[0023] Figure 4 This is a schematic diagram of the installation position of this utility model.

[0024] In the diagram: 1. Housing; 2. Main control circuit board; 3. Vibration energy harvesting module; 301. Metal substrate; 302. Piezoelectric ceramic sheet; 303. Counterweight; 4. Power management circuit; 5. Sensing unit; 501. MEMS accelerometer; 502. Multifunctional vibrating string unit; 503. Attitude sensor; 6. Wireless communication module; 7. Signal processing and control module; 8. Mounting flange. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0026] To facilitate understanding of this utility model, a more comprehensive description will be given below with reference to the accompanying drawings. Several embodiments of this utility model are provided. However, this utility model can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this utility model will be more thorough and complete.

[0027] Please see Figure 1-4This embodiment provides a multifunctional integrated passive sensing node device for bridges, including a housing 1, a main control circuit board 2 disposed inside the housing 1, a vibration energy harvesting module 3, a power management circuit 4, a sensing unit 5, a wireless communication module 6, a signal processing and control module 7, and a mounting flange 8 for fixing to the bridge structure at the bottom of the housing 1.

[0028] The output of the vibration energy harvesting module 3 is connected to the input of the power management circuit 4. The output of the power management circuit 4 supplies power to the sensing unit 5, the wireless communication module 6, and the signal processing and control module 7. The signal processing and control module 7 is connected to the sensing unit 5 and the wireless communication module 6 respectively. The resonant frequency of the vibration energy harvesting module 3 is designed to be 5Hz-15Hz.

[0029] The bridge vibrates due to vehicle and wind loads, causing the piezoelectric cantilever beam at the bottom of the drive unit to generate a small amount of alternating current (AC). This AC is rectified and regulated into stable direct current (DC) by the power management circuit 4 and stored in a supercapacitor. At this time, except for the voltage monitoring unit, other modules are powered off and in sleep mode, resulting in low system power consumption.

[0030] The signal processing and control module 7 monitors the supercapacitor voltage. When it reaches a preset threshold, such as 3.0V, it wakes up the main control chip and starts the system. The main control chip controls the power management circuit 4 to supply power to the sensing unit 5 and the wireless communication module 6, and collects data according to a preset timing sequence: first, it reads the data from the attitude sensor 503 to correct subsequent data, then it collects the triaxial vibration acceleration data from the MEMS accelerometer 501, and finally it applies sweep frequency excitation to the excitation coil of the multifunctional vibrating string unit 502, calculates the strain value, and measures the resistance to convert it into the ambient temperature value.

[0031] The main control chip packages and filters sensor data, adds timestamps to form a complete data packet, and initiates the wireless communication module 6 to transmit the data to the data aggregation gateway via the LoRa or NB-IoT network. After the data transmission is complete, the main control chip powers off the wireless communication module 6, cutting off the power supply to the sensor and its own module. The system, except for the monitoring function of the power management circuit 4, reverts to deep sleep mode, waiting for the supercapacitor to accumulate energy to the threshold voltage.

[0032] like Figure 1 and Figure 2 As shown, the vibration energy harvesting module 3 is a piezoelectric cantilever beam structure, including a metal substrate 301, a piezoelectric ceramic sheet 302 attached to the metal substrate 301, and a counterweight 303 at the free end of the metal substrate 301. The power management circuit 4 includes a rectifier unit, a voltage regulator unit, and an energy storage unit, wherein the energy storage unit is a supercapacitor.

[0033] The vibration of the bridge drives the cantilever beam to bend back and forth. The piezoelectric ceramic sheet 302 generates alternating charge due to deformation, outputting a small amount of alternating current. The power management circuit 4 receives the alternating current from the piezoelectric cantilever beam, converts it into direct current through the rectifier unit, and then adjusts it to a suitable voltage through the voltage regulator unit. The processed electrical energy is continuously stored in the supercapacitor. When the main control chip detects that the voltage of the supercapacitor has reached the set working threshold, it connects the circuit to power the entire system.

[0034] like Figure 1 and Figure 2 and Figure 3 As shown, the sensing unit 5 includes a MEMS accelerometer 501, a multifunctional vibrating string unit 502, and an attitude sensor 503. The MEMS accelerometer 501 and the attitude sensor 503 are mounted on the main control circuit board 2. The multifunctional vibrating string unit 502 includes a sealed metal cavity, which is rigidly bonded to the bridge structure with high-strength epoxy resin. A pre-tensioned metal string and an excitation coil are disposed inside the metal cavity. The signal processing and control module 7 is configured to: obtain the strain value by applying a sweep frequency excitation to the excitation coil and detecting the resonant frequency of the metal string, and obtain the ambient temperature value by measuring the resistance value of the excitation coil.

[0035] After the MEMS accelerometer 501 is awakened by the main control chip in the main control circuit board 2, it immediately measures the vibration acceleration data in the X, Y, and Z directions and transmits it to the main control chip. After the attitude sensor 503 is awakened, it measures the current tilt angle and other attitude data of the node and sends it to the main control chip to correct the reference of the accelerometer. When the multi-functional vibrating string unit 502 is working, the main control chip sends a sweep frequency electrical signal to its excitation coil. The coil generates a magnetic field to excite the metal string to resonate. The vibration pickup circuit detects the resonance frequency, and the main control chip converts the frequency value into a strain value. At the same time, the main control chip measures the resistance of the excitation coil and converts it into a temperature value.

[0036] like Figure 1 and Figure 2 As shown, wireless communication module 6 is either a LoRa communication module or an NB-IoT communication module.

[0037] It spends most of its time in sleep mode after power failure. When woken up by the main control chip, it receives pre-packaged data, sends the data packets to the remote gateway via the wireless network, and then immediately goes into sleep mode after power failure.

[0038] The working process of this utility model is as follows: When using this type of multifunctional integrated passive sensing node device for bridges, the bridge first vibrates due to vehicle traffic, wind loads, etc., driving the piezoelectric cantilever beam energy harvesting module at the bottom of the device to continuously generate electricity, producing a small amount of alternating current. The generated alternating current is sent to the power management circuit 4, where it is rectified and regulated to become stable direct current, which is then stored in a supercapacitor. At this time, except for the voltage monitoring unit in the power management circuit 4, all other modules, including the main control chip, are in a power-off sleep state, resulting in extremely low system power consumption.

[0039] The signal processing and control module 7 continuously monitors the voltage of the supercapacitor. When the accumulated voltage reaches a preset operating threshold, such as 3.0V, the main control chip is activated, determines that the energy is sufficient to complete a measurement and transmission task, and then starts the entire system. The main control chip controls the power management circuit 4 to supply power to the sensing unit 5 and the wireless communication module 6.

[0040] The main control chip efficiently collects data from various sensors according to a preset timing sequence: First, it reads the data from the attitude sensor 503 to obtain the node's own attitude for subsequent data correction. Then, it collects the triaxial vibration acceleration data from the MEMS accelerometer 501. Finally, it applies a sweep frequency excitation to the excitation coil of the multifunctional vibrating string unit 502, calculates the strain value by detecting the resonant frequency of the metal string, and simultaneously measures the resistance value of the coil to calculate the ambient temperature value.

[0041] The main control chip packages and filters all collected sensor data, adding precise timestamps to form a complete data packet. The main control chip then activates the wireless communication module 6, sending the data packet via LoRa or NB-IoT network to a data aggregation gateway hundreds of meters away. After data transmission is complete, the main control chip immediately commands the wireless communication module 6 to power off. The main control chip then cuts off power to all sensors and its own modules. The entire system, except for the monitoring function of the power management circuit 4, re-enters deep sleep mode, awaiting the supercapacitor's next energy accumulation to the threshold voltage.

[0042] All standard parts used in this application can be purchased from the market. The specific connection methods of each part adopt conventional methods such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts and equipment all adopt conventional models in the prior art. Among them, the multi-functional vibrating string unit, attitude sensor, MEMS accelerometer and vibration energy harvesting module are existing mature technologies, so their principles will not be elaborated. The control method is through a controller. The control circuit of the controller can be implemented by a person skilled in the art through simple circuit connection. It is common knowledge in the field, so this application will not explain the control method and circuit connection in detail.

[0043] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A multifunctional integrated passive sensing node device for bridges, characterized in that: Includes a housing (1), a main control circuit board (2) disposed inside the housing (1), a vibration energy harvesting module (3), a power management circuit (4), a sensing unit (5), a wireless communication module (6), and a signal processing and control module (7). The bottom of the housing (1) is provided with an installation flange (8) for fixing to the bridge structure. The output terminal of the vibration energy harvesting module (3) is connected to the input terminal of the power management circuit (4). The output terminal of the power management circuit (4) supplies power to the sensing unit (5), the wireless communication module (6), and the signal processing and control module (7). The signal processing and control module (7) is connected to the sensing unit (5) and the wireless communication module (6) respectively.

2. The multifunctional integrated passive sensing node device for bridges according to claim 1, characterized in that: The vibration energy harvesting module (3) is a piezoelectric cantilever beam structure, including a metal substrate (301), a piezoelectric ceramic sheet (302) attached to the metal substrate (301), and a counterweight (303) at the free end of the metal substrate (301).

3. The multifunctional integrated passive sensing node device for bridges according to claim 1, characterized in that: The power management circuit (4) includes a rectifier unit, a voltage regulator unit and an energy storage unit, wherein the energy storage unit is a supercapacitor.

4. The multifunctional integrated passive sensing node device for bridges according to claim 1, characterized in that: The sensing unit (5) includes a MEMS accelerometer (501), a multi-functional vibrating string unit (502), and an attitude sensor (503). The MEMS accelerometer (501) and the attitude sensor (503) are mounted on the main control circuit board (2). The multi-functional vibrating string unit (502) includes a sealed metal cavity, which is rigidly bonded to the bridge structure with high-strength epoxy resin adhesive. The metal cavity is provided with a pre-tensioned metal string and an excitation coil. The signal processing and control module (7) is configured to: obtain the strain value by applying a sweep frequency excitation to the excitation coil and detecting the resonant frequency of the metal string, and obtain the ambient temperature value by measuring the resistance value of the excitation coil.

5. A multifunctional integrated passive sensing node device for bridges according to claim 1, characterized in that: The wireless communication module (6) is a LoRa communication module or an NB-IoT communication module.

6. A multifunctional integrated passive sensing node device for bridges according to claim 1, characterized in that: The resonant frequency of the vibration energy harvesting module (3) is designed to be 5Hz-15Hz.

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