A road surface embedded wireless intelligent aggregate integrating sensing and energy capturing and a preparation method thereof

Abstract

The application discloses a kind of integrated sensing-capturing integrated road embedded wireless intelligent aggregate and preparation method thereof, belong to road engineering intelligent aggregate technical field.The wireless intelligent aggregate includes encapsulation shell, the cube piezoelectric core being arranged in the encapsulation shell inside, electronic function module being arranged in the cube piezoelectric core inside.The preparation method includes preparation encapsulation shell, preparation cube piezoelectric core, install electronic function module in cube shell inside, function test and the cube piezoelectric core is placed into the installation cavity of encapsulation shell.The application adopts pure piezoelectric self-capturing energy structure, cancels electromagnetic coil, permanent magnet and cantilever beam and other complex components, structure is simpler, assembly is easier, long-term service reliability is higher.

Description

Technical Field

[0001] This invention belongs to the field of intelligent aggregate technology for road engineering, specifically relating to a road surface embedded wireless intelligent aggregate integrating sensing and energy harvesting and its preparation method. Background Technology

[0002] With the development of smart highways and digital management of road infrastructure, in-situ sensing of the internal condition of pavement structures is gradually becoming an important direction for road engineering health monitoring. Traditional pavement inspection methods mostly rely on manual inspections, vehicle-mounted inspections, or periodic non-destructive testing, making it difficult to continuously acquire information on temperature, dynamic response, vehicle load effects, and service condition changes within the pavement structure. Embedding sensor nodes inside the pavement can directly obtain real-time response information during pavement structure service, representing a crucial technical approach for long-term pavement health monitoring.

[0003] However, embedded sensing nodes in road surfaces are subjected to complex environments such as high-temperature paving, heavy compaction, repeated vehicle loads, freeze-thaw cycles, water erosion, and asphalt encapsulation, facing challenges such as power supply difficulties, limited size, structural vulnerability, and incompatibility with surrounding aggregate interfaces. Using external power or frequent battery replacements not only increases construction and maintenance costs but also disrupts the continuity of the road structure. Furthermore, using regular cylindrical or spherical encapsulations results in significant differences from the shape of natural aggregates, potentially affecting the interlocking of the asphalt mixture skeleton and the local stress state.

[0004] In existing self-powered embedded nodes, some schemes employ electromagnetic induction or piezoelectric-electromagnetic coupling structures for energy harvesting. Electromagnetic structures typically require permanent magnets, coils, cantilever beams, or relatively moving parts, resulting in complex internal structures and high requirements for encapsulation space, installation precision, and movement clearance. Within the limited space of coarse aggregate scale, electromagnetic coils and magnets increase node volume, assembly difficulty, and failure risk. Furthermore, cantilever beam structures are susceptible to fatigue, collision, jamming, or damage under asphalt paving compaction and long-term loads.

[0005] Therefore, it is necessary to propose a roadbed embedded smart aggregate with a simpler structure, more compact size, stronger compressive durability, adaptability to multi-directional loads, and energy harvesting solely through piezoelectric functions. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a road-embedded wireless smart aggregate that integrates sensing and energy harvesting.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A road-embedded wireless smart aggregate integrating sensing and energy harvesting includes an encapsulation shell, a cubic piezoelectric core disposed inside the encapsulation shell, and an electronic functional module disposed inside the cubic piezoelectric core.

[0008] Furthermore, the cubic piezoelectric core includes a cubic shell and six piezoelectric ceramic sheets respectively disposed on the six outer surfaces of the cubic shell. The six piezoelectric ceramic sheets are used to capture energy from different directions and generate charge output under vehicle load, road vibration or road structure deformation.

[0009] Furthermore, the electronic functional module is used to identify the vehicle load direction, vibration events, wheel load strength, or road structure response state based on the output signals of different surface piezoelectric ceramic sheets.

[0010] Furthermore, the electronic functional module includes an energy storage unit that powers the wireless intelligent aggregate power unit, and a charge acquisition unit, an energy management unit, a microcontroller, and a wireless communication unit connected in sequence. The charge acquisition unit is connected to the six piezoelectric ceramic plates and is used to rectify, filter, and collect the AC charge or pulse voltage generated by the piezoelectric ceramic plates. The energy management unit is used to rectify, boost, and stabilize the electrical energy corresponding to the charge collection and store it in the energy storage unit.

[0011] Furthermore, the six piezoelectric ceramic sheets are connected to the charge acquisition unit in the electronic functional module via independent channels. The microcontroller identifies the direction of vehicle load, the strength of wheel load, or the road structure response state based on the output voltage, output charge, or peak time difference of the different surface piezoelectric ceramic sheets. The identified signals are then transmitted to the roadside data gateway or terminal via a wireless communication unit.

[0012] Furthermore, the electronic functional module also includes a temperature measurement unit and an inertial measurement unit, which are respectively connected to the microcontroller.

[0013] Furthermore, the output signal of the piezoelectric ceramic sheet, the temperature signal of the temperature measurement unit, and the motion signal of the inertial measurement unit are fused together by a microcontroller and transmitted to a roadside data gateway or terminal via a wireless communication unit.

[0014] Furthermore, the encapsulation shell is a composite material-shaped encapsulation shell, and its outer surface is an irregular polyhedron or a natural coarse aggregate-like shape; the encapsulation shell is provided with an installation cavity that matches the cubic piezoelectric core.

[0015] Furthermore, a force transmission layer and a buffer layer are provided between the encapsulation shell and the cubic piezoelectric core; the force transmission layer is used to transmit external loads and vibrations to the piezoelectric ceramic sheet; the buffer layer is used to absorb the impact of construction and operation loads on the internal circuitry.

[0016] Furthermore, the present invention also provides a method for preparing wireless smart aggregate as described in part or all of the above, specifically including the following steps: S1. Generate an external encapsulation shell model that mimics the shape of natural coarse aggregate based on the shape of the aggregate, and design an internal mounting cavity to accommodate the cubic piezoelectric core. S2. Prepare a cubic shell and install square piezoelectric ceramic sheets on the six outer surfaces of the cubic shell respectively; S3. Install a charge acquisition unit, an energy management unit, a microcontroller, a wireless communication unit, and an energy storage unit inside the cubic shell, and electrically connect six square piezoelectric ceramic plates to the charge acquisition unit; S4. Perform electrical performance testing and sealing treatment on the cubic piezoelectric core; S5. Place the cubic piezoelectric core into the mounting cavity of the outer aggregate-shaped encapsulation shell, and perform potting, bonding and outer surface protection treatment to obtain a complete road-embedded wireless smart aggregate.

[0017] Furthermore, in S3, a temperature measurement unit and an inertial measurement unit are also installed inside the cubic shell.

[0018] In addition, the present invention also provides a road structure health monitoring system, including a roadside data gateway and wireless smart aggregates prepared by all the above-described preparation methods. Multiple wireless smart aggregates are embedded inside the road structure and acquire electrical energy generated by vehicle load and road vibration through piezoelectricity. The newly acquired voltage output information, temperature information, acceleration information and energy state information are wirelessly transmitted to the roadside data gateway.

[0019] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: 1. This invention adopts a pure piezoelectric self-harvesting energy structure, eliminating complex components such as electromagnetic coils, permanent magnets, and cantilever beams, resulting in a simpler structure, easier assembly, and higher long-term service reliability. Simultaneously, six piezoelectric ceramic plates are arranged on the six faces of the cube, enabling energy harvesting from loads and vibrations from different directions (top, bottom, left, right, front, and back), making it more suitable for the complex three-dimensional stress environment inside road surfaces.

[0020] 2. The cubic piezoelectric core of this invention can accommodate multiple circuit boards, energy storage units, and wireless communication units, achieving integrated piezoelectric energy harvesting, energy management, signal acquisition, wireless communication, and status monitoring. Furthermore, the piezoelectric ceramic sheet can be used for energy harvesting and as a trigger signal for vehicle loads or road vibration events, enabling low-power event-driven acquisition.

[0021] 3. The present invention uses an external encapsulation shell that mimics the shape of natural coarse aggregate, which can simulate the appearance of natural coarse aggregate and form a good interlocking and bonding with the surrounding aggregate and asphalt mortar, thereby reducing the impact on the stress continuity of the pavement structure.

[0022] 4. By setting up a partitioned force transmission and buffering encapsulation structure (force transmission layer and buffer layer), this invention takes into account both the force efficiency of the piezoelectric sheet and the protection of the internal circuit, which can improve the survivability of smart aggregates under high-temperature paving, compaction construction and long-term load. Attached Figure Description

[0023] The accompanying drawings are incorporated in and form part of this specification, and together with the description serve to explain the principles of the invention.

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of the wireless intelligent aggregate of the present invention; Figure 2 This is an exploded view of the cubic piezoelectric core structure of the present invention; Figure 3 This is a functional block diagram of the system circuit of the present invention; Figure 4 This is an assembly diagram of the present invention.

[0026] Among them, 1 is the encapsulation shell, 2 is the cubic piezoelectric core, 21 is the cubic shell, 22 is the piezoelectric ceramic sheet, 3 is the electronic functional module, 31 is the charge acquisition unit, 32 is the energy management unit, 33 is the energy storage unit, 34 is the microcontroller, 35 is the wireless communication unit, 36 is the temperature measurement unit, and 37 is the inertial measurement unit. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail. The embodiments described below are not representative of all embodiments consistent with this invention. Rather, they are merely examples consistent with some aspects of the invention as detailed in the appended claims.

[0028] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0029] Example 1 like Figures 1 to 3 As shown, this embodiment provides a road-embedded wireless smart aggregate integrating sensing and energy harvesting, including an encapsulation shell 1, a cubic piezoelectric core 2 disposed inside the encapsulation shell 1, and an electronic functional module 3 disposed inside the cubic piezoelectric core 2.

[0030] Furthermore, such as Figure 2 As shown, the cubic piezoelectric core 2 includes a cubic shell 21 and six piezoelectric ceramic sheets 22 respectively disposed on the six outer surfaces of the cubic shell 21. The six piezoelectric ceramic sheets 22 are used to capture energy from different directions and generate charge output under vehicle load, road vibration or road structure deformation.

[0031] Specifically, the cubic shell 21 is made of high-strength insulating material, and the six piezoelectric ceramic sheets 22 are all square, respectively pasted or embedded on the upper, lower, left, right, front, and rear surfaces of the cubic shell 21. Each piezoelectric ceramic sheet has an electrode layer and a protective insulating layer on its surface. When the vehicle wheel load acts on the road surface, the compression, shearing, vibration, and local deformation generated inside the road structure are transmitted to the cubic piezoelectric core 2 through the encapsulation shell 1, causing the piezoelectric ceramic sheets 22 on different surfaces to be compressed or bent and deform and output charges.

[0032] Furthermore, the electronic functional module 3 is used to identify the vehicle load direction, vibration events, wheel load strength, or road structure response state based on the output signals of the different surface piezoelectric ceramic sheets 22.

[0033] Furthermore, the electronic functional module 3 includes an energy storage unit 33 that powers the wireless intelligent aggregate power unit, and a charge acquisition unit 31, an energy management unit 32, a microcontroller 34, and a wireless communication unit 35 connected in sequence. The charge acquisition unit 31 is connected to six piezoelectric ceramic plates 22. The charge acquisition unit 31 is used to rectify, filter, and collect the AC charge or pulse voltage generated by the piezoelectric ceramic plates 22. The energy management unit 32 is used to rectify, boost, and stabilize the electrical energy corresponding to the charge collection and store it in the energy storage unit 33.

[0034] Specifically, the electronic functional module 3 may adopt a stacked, plug-in, or flexible interconnection circuit structure.

[0035] In a preferred embodiment of this invention, the electronic functional module 3 adopts a stacked circuit board structure, including a charge acquisition unit board, an energy management unit board, a microcontroller board, a wireless communication circuit board, and an energy storage unit board. The charge acquisition unit board, energy management unit board, microcontroller board, wireless communication circuit board, and energy storage unit board are respectively equipped with a charge acquisition unit 31, an energy management unit 32, a microcontroller 34, a wireless communication unit 35, and an energy storage unit 33.

[0036] Furthermore, the output ends of the six piezoelectric ceramic sheets 22 are introduced into the cubic housing 21 through wires, flexible circuit boards, or metallized vias, and connected to the charge acquisition unit 31. The six piezoelectric ceramic sheets 22 are connected to the charge acquisition unit 31 in an independent channel, series, parallel, or series-parallel combination manner.

[0037] In a preferred embodiment of this invention, the six piezoelectric ceramic sheets 22 are connected to the charge acquisition unit 31 in the electronic functional module 3 via independent channels. The microcontroller 34 can identify the direction of vehicle load, the strength of wheel load, or the response state of road structure based on the output voltage, output charge, or output peak time difference of the piezoelectric ceramic sheets 22 with different surfaces.

[0038] Specifically, when a vehicle passes by, the piezoelectric ceramic sheet 22 will have a voltage peak. The time interval between the piezoelectric peaks under the action of the front and rear wheels is used to determine the vehicle travel time. The vehicle speed is determined based on the distance between the front and rear axles. The strength of the wheel load can be determined based on the magnitude of the output signal peak, thus jointly reflecting the response state of the road structure.

[0039] Furthermore, the output signal of the piezoelectric ceramic sheet 22 is fused and processed by the microcontroller 34 and sent to the roadside data gateway or terminal through the wireless communication unit 35.

[0040] Specifically, the energy storage unit 33 may be a supercapacitor, a rechargeable button battery, a lithium thionyl chloride battery, or a combination of various energy storage devices.

[0041] Specifically, the wireless communication unit 35 can employ wireless communication technologies such as LoRa, BLE, NB-IoT, and ZigBee, or combinations thereof. LoRa or NB-IoT is used for long-distance data transmission, while BLE or ZigBee is used for near-field parameter configuration, device maintenance, and small-scale data reading. The wireless communication unit 35 can select an appropriate wireless communication technology based on the actual application scenario and conditions.

[0042] Furthermore, the encapsulation shell 1 is shaped like aggregate, and its outer surface is an irregular polyhedron or a natural coarse aggregate-like shape; the encapsulation shell 1 is provided with an installation cavity that matches the cubic piezoelectric core 2.

[0043] Specifically, the outer shell 1 has uneven edges and rough textures on its outer surface to simulate the morphology of natural crushed stone aggregate, enabling the smart aggregate to interlock, interlock, and bond with the surrounding asphalt mixture aggregate. The outer shell 1 can be prepared by 3D scanning of real aggregate, point cloud reconstruction, and 3D printing, or generated by fractal geometry algorithms or random polyhedron algorithms. The material of the outer shell 1 can be polyetheretherketone, polyaryletherketone, nylon, epoxy resin, glass fiber reinforced resin, carbon fiber reinforced resin, or mineral filler reinforced composite material.

[0044] Furthermore, a force transmission layer and a buffer layer are provided between the encapsulation shell 1 and the cubic piezoelectric core 2; the force transmission layer is used to transmit external loads and vibrations to the piezoelectric ceramic sheet 22; the buffer layer is used to reduce the impact damage to the internal circuitry under asphalt paving, compaction, and long-term vehicle loads. The force transmission layer and buffer layer can be arranged in zones according to different locations: the force transmission layer is located in the corresponding area of ​​the piezoelectric ceramic sheet 22, using a higher modulus material to ensure force transmission; the buffer layer is located in the corresponding area around each functional unit, using a lower modulus material for buffer protection.

[0045] Specifically, the force transmission layer may be made of high-modulus epoxy resin, mineral filler-reinforced resin or thermally conductive potting material; the buffer protection layer may be made of silicone rubber, polyurethane elastomer or flexible epoxy material.

[0046] Example 2 Based on Example 1, this example provides a road surface embedded wireless smart aggregate integrating sensing and energy harvesting, such as... Figure 3 As shown, the electronic functional module 3 also includes a temperature measurement unit 36 ​​and an inertial measurement unit 37, both connected to the microcontroller 34. The temperature measurement unit 36 ​​is used to collect the internal temperature of the road surface structure, and the inertial measurement unit 37 is used to collect triaxial acceleration, angular velocity, or attitude information. The temperature signal from the temperature measurement unit 36 ​​and the motion signal from the inertial measurement unit 37 are fused by the microcontroller 34 and transmitted to the roadside data gateway or terminal via the wireless communication unit 35.

[0047] Example 3 Based on Example 2, this example provides a method for preparing a roadbed-embedded wireless smart aggregate integrating sensing and energy harvesting. This example prepares a smart aggregate with an equivalent particle size of approximately 40 mm and mimicking the shape of aggregates. The specific steps include: S1. Preparing the packaging shell 1: First, the outer packaging shell 1, which mimics the shape of aggregate, is reconstructed using a point cloud model obtained by 3D scanning of real 35-45 mm basalt coarse aggregate. The outer surface of the packaging shell 1 retains the edges, textures, and irregular shapes of natural aggregate.

[0048] The encapsulation shell 1 adopts a split structure, with a cubic mounting cavity, upper and lower cover structures, positioning structure and sealing groove designed inside the model.

[0049] Then, the outer packaging shell 1, which mimics the shape of aggregate, is prepared by 3D printing, resin casting, molding or machining, and then subjected to surface roughening, cleaning and drying.

[0050] S1. Preparation of cubic piezoelectric core 2: The cubic shell 21 of the cubic piezoelectric core 2 has a side length of 26 mm and is made of glass fiber reinforced epoxy resin or PEEK composite material. The interior of the cubic shell 21 has a receiving space, with reserved mounting areas for piezoelectric ceramic sheets 22, lead wire channels and protective grooves on six sides.

[0051] A square piezoelectric ceramic sheet 22 is disposed on each of the six outer surfaces of the cubic shell 21. The piezoelectric ceramic sheet 22 has a size of 20 mm × 20 mm × 0.3 mm. The piezoelectric ceramic sheet 22 is attached to the outer surface of the cubic shell 21 with conductive epoxy adhesive. A thin insulating protective film is disposed on the outer side of the piezoelectric ceramic sheet 22, and the edges are sealed with flexible sealant.

[0052] The positive and negative electrodes of the six piezoelectric ceramic sheets 22 are introduced into the interior of the cubic housing 21 via flexible leads or flexible printed circuit boards. To facilitate identification of the piezoelectric response in different directions, the six piezoelectric channels are numbered PZ-U, PZ-D, PZ-L, PZ-R, PZ-F, and PZ-B, corresponding to the top, bottom, left, right, front, and rear surfaces, respectively.

[0053] S3. Install electronic functional module 3 inside the cubic shell 21: The cubic piezoelectric core 21 employs a stacked circuit board layout. From top to bottom, it consists of a charge harvesting circuit board, an energy management circuit board, a microcontroller board, a wireless communication unit board, a sensor board, and an energy storage unit board. The circuit boards are connected via inter-board connectors, flexible cables, or soldered pins.

[0054] The charge acquisition circuit board features six piezoelectric input interfaces, each of which can be configured with an independent bridge rectifier circuit, a low-leakage diode rectifier circuit, or a synchronous rectifier circuit. The six rectified outputs can be connected to a common energy storage bus or retained as independent acquisition branches for direction identification.

[0055] The energy management circuit board includes a boost circuit, a voltage regulator circuit, a charging management circuit, and a voltage monitoring circuit. The pulsed electrical energy generated by the piezoelectric ceramic sheet 22 first enters the charge acquisition circuit, and after preliminary filtering by the energy storage capacitor, it is input to the energy management circuit. When the voltage reaches the set threshold, the energy management circuit supplies power to the microcontroller 34 and the wireless communication unit 35.

[0056] The microcontroller board uses a low-power microcontroller 34, featuring an ADC sampling interface, a low-power sleep mode, and external interrupt wake-up functionality. The wireless communication unit can utilize a combination of LoRa and BLE, where LoRa transmits monitoring data to the roadside gateway, and BLE is used for short-range parameter setting and device status reading. The sensor board is equipped with a temperature measurement unit 36 ​​(temperature sensor) and an inertial measurement unit 37 (six-axis inertial measurement unit) to acquire information on internal road surface temperature, acceleration, and attitude changes.

[0057] S4, Functional Testing The functions of six-channel piezoelectric output, charge acquisition, energy storage and charging, microcontroller 34 wake-up, wireless communication, and temperature and acceleration acquisition were tested.

[0058] S5. Place the cubic piezoelectric core 2 into the mounting cavity of the package housing 1: like Figure 4 As shown, the tested and qualified cubic piezoelectric core 2 is placed into the cavity of the external aggregate-like encapsulation shell 1. Force transmission layer material and buffer layer material are respectively injected into the corresponding areas of the piezoelectric ceramic sheet 22 and the circuit areas of each functional unit. High-modulus epoxy resin or mineral-filled reinforced epoxy resin is used as the force transmission layer in the corresponding areas of the piezoelectric ceramic sheet 22; low-modulus silicone rubber or polyurethane elastomer is used as a buffer protective layer around each functional unit. The upper and lower covers of the encapsulation shell 1 are aligned using a positioning structure and bonded with high-strength structural adhesive. After bonding, the joint of the encapsulation shell 1 is sealed a second time, and a wear-resistant, waterproof, and chemically resistant protective coating is sprayed onto the outer surface. The surface of the encapsulation shell 1 can also have a slightly rough texture or be sandblasted to enhance its adhesion to the asphalt adhesive. Finally, the target wireless intelligent aggregate is obtained.

[0059] Once the target wireless smart aggregate is obtained, piezoelectric output calibration, load response calibration, waterproof sealing test, high temperature resistance test, and communication test are performed on it to establish the correspondence between piezoelectric output and vehicle load or road vibration events.

[0060] Ten wireless smart aggregate samples were prepared according to the specific implementation method described above, and systematic performance verification tests were conducted. The results are as follows: 1. Packaging reliability testing (1) High temperature durability test: The sample was placed in an oven at 180℃ ±5℃ for 48 hours to simulate asphalt paving and high temperature environment in summer. After cooling, the outer casing 1 showed no deformation or cracking. The internal circuit functioned normally and the insulation resistance was >100MΩ.

[0061] (2) Waterproof sealing test: According to IP68 standard, the sample was immersed in a water tank with a depth of 2 meters and a water temperature of 85℃ ±2℃ for 168 hours. After taking it out, it was wiped dry and the lid was opened to check that the inside was completely dry and there were no signs of moisture intrusion.

[0062] (3) Vibration and shock fatigue test: Random vibration with a frequency of 5-500Hz and a total root mean square acceleration of 10g was applied to the sample on an electromagnetic vibration table for 24 hours (equivalent to more than 5 million heavy vehicle load impacts). Subsequently, a half-sine wave impact test was performed with a peak acceleration of 50g, a pulse width of 11ms, and three impacts in each of the three axes. After the test, the sample structure was intact, and all functional tests were normal.

[0063] 2. Integrated Sensing-Energy Harvesting Performance Test (1) Stress sensing accuracy and linearity: Quasi-static and dynamic (1Hz) compressive loads of 0 to 2.5 MPa were applied to the packaged wireless smart aggregate on a precision universal testing machine. A high-precision standard force sensor was used as a reference. The test results show that the stress values ​​calculated by the piezoelectric path are in high agreement with the standard values. Within the 0-2.0 MPa range, the linearity error is <±1.5% FS (full scale), and the repeatability error is <±1.0%. Its dynamic response is good and it can accurately capture load changes.

[0064] (2) Energy harvesting efficiency test: The sample was rigidly fixed on a vibration table to simulate typical traffic vibration conditions: frequency 12Hz, acceleration amplitude 1.2g. Its output power under different loads was measured. The total average output power of the entire piezoelectric system was 6.45mW.

[0065] (3) System self-consistency verification: The working mode of the wireless smart aggregate was set as follows: an average of 20 "vehicle events" were triggered per hour. After each event wake-up, the system worked for about 2 seconds (including sensing, processing, and LoRa transmission), and the average energy consumption per cycle was measured to be about 300 mJ. Based on this, the average power consumption required for the system to maintain this working mode was calculated to be about 1.67 mW. Compared with the 6.45 mW energy harvesting power measured under simulated traffic flow (12Hz, 1.2g continuous vibration), the energy harvesting efficiency is 3.86 times the power consumption, which confirms that it has a significant energy surplus under typical working conditions and can achieve long-term self-powered operation.

[0066] 3. Communication and overall system testing (1) LoRa long-distance penetration test: The wireless smart aggregate was embedded in a 40cm thick AC-13 asphalt mixture specimen and placed in an open area. A commercial LoRa gateway with a receiving sensitivity of -140 dBm was used. The test results showed that at a straight-line distance of 650 meters, the data packet reception success rate (RSS) remained above 98%.

[0067] (2) BLE near-field maintenance function: With the wireless smart aggregate completely embedded in the asphalt specimen, a regular smartphone (supporting BLE 5.0) is used for testing. The maximum effective detection and stable connection distance is 3.5 meters, and after connection, device information reading, sampling parameter modification and a small amount of historical data export can be completed smoothly.

[0068] In summary, the roadbed-embedded wireless intelligent aggregate system provided by this invention, which integrates sensing and energy harvesting, can operate normally in complex environments such as high-temperature paving, heavy compaction, repeated vehicle loads, freeze-thaw cycles, water erosion, and asphalt media encapsulation, and exhibits excellent dynamic response, accurately capturing load changes. Furthermore, it possesses significant energy surplus under typical operating conditions, enabling long-term self-powered operation.

[0069] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention.

[0070] It should be understood that the present invention is not limited to the content already described above, and various modifications and changes can be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A type of road surface embedded wireless smart aggregate integrating sensing and energy harvesting, characterized in that, It includes a package shell (1), a cubic piezoelectric core (2) disposed inside the package shell (1), and an electronic functional module (3) disposed inside the cubic piezoelectric core (2). The cubic piezoelectric core (2) includes a cubic shell (21) and six piezoelectric ceramic sheets (22) respectively disposed on the six outer surfaces of the cubic shell (21). The six piezoelectric ceramic sheets (22) are used to capture energy from different directions and generate charge output under vehicle load, road vibration or road structure deformation. The electronic functional module (3) is used to identify the vehicle load direction, vibration events, wheel load strength and road structure response status based on the output signals of different surface piezoelectric ceramic sheets (22).

2. The roadbed embedded wireless smart aggregate integrating sensing and energy harvesting as described in claim 1, characterized in that, The electronic functional module (3) includes: an energy storage unit (33) for powering the wireless intelligent aggregate power unit, and a charge acquisition unit (31), an energy management unit (32), a microcontroller (34), and a wireless communication unit (35) connected in sequence; the charge acquisition unit (31) is connected to six piezoelectric ceramic plates (22), and the charge acquisition unit (31) is used to rectify, filter, and collect the AC charge or pulse voltage generated by the piezoelectric ceramic plates (22); the energy management unit (32) is used to rectify, boost, stabilize, and store the collected electrical energy in the energy storage unit (33).

3. The roadbed embedded wireless smart aggregate integrating sensing and energy harvesting as described in claim 2, characterized in that, The six piezoelectric ceramic sheets (22) are connected to the charge acquisition unit (31) in the electronic functional module (3) via independent channels.

4. The roadbed embedded wireless smart aggregate integrating sensing and energy harvesting as described in claim 3, characterized in that, The microcontroller (34) identifies the direction of the vehicle load, the strength of the wheel load, or the response state of the road structure based on the output voltage, output charge, or output peak time difference of the piezoelectric ceramic sheets (22) on different surfaces, and sends the identified signal to the roadside data gateway or terminal through the wireless communication unit (35).

5. The roadbed embedded wireless smart aggregate integrating sensing and energy harvesting as described in claim 2, characterized in that, The electronic functional module (3) also includes a temperature measurement unit (36) and an inertial measurement unit (37) respectively connected to the microcontroller (34).

6. The roadbed embedded wireless smart aggregate integrating sensing and energy harvesting as described in claim 5, characterized in that, The output signal of the piezoelectric ceramic sheet (22), the temperature signal of the temperature measurement unit (36) and the motion signal of the inertial measurement unit (37) are fused by the microcontroller (34) and sent to the roadside data gateway or terminal through the wireless communication unit (35).

7. The roadbed embedded wireless smart aggregate integrating sensing and energy harvesting as described in claim 1, characterized in that, The encapsulation shell (1) is an imitation aggregate shape encapsulation shell (1), and its outer surface is an irregular polyhedron or a natural coarse aggregate shape; the encapsulation shell (1) has an installation cavity inside that matches the cubic piezoelectric core (2); A force transmission layer and a buffer layer are provided between the encapsulation shell (1) and the cubic piezoelectric core (2); the force transmission layer is used to transmit external loads and vibrations to the piezoelectric ceramic sheet (22); the buffer layer is used to absorb the impact of construction and operation loads on the internal circuit.

8. A method for preparing road surface embedded wireless smart aggregate integrating sensing and energy harvesting, characterized in that, The wireless smart aggregate is the wireless smart aggregate according to any one of claims 1 to 7, and the preparation method specifically includes the following steps: S1. Generate an external encapsulation shell (1) model based on the shape of natural coarse aggregate, and design an installation cavity inside it to accommodate the cubic piezoelectric core (2). S2. Prepare a cubic shell (21) and install square piezoelectric ceramic sheets (22) on the six outer surfaces of the cubic shell (21). S3. Install a charge acquisition unit (31), an energy management unit (32), a microcontroller (34), a wireless communication unit (35), and an energy storage unit (33) inside the cubic shell (21), and electrically connect six square piezoelectric ceramic plates (22) to the charge acquisition unit (31); S4. Perform electrical performance tests on the cubic piezoelectric core (2) and the electronic functional module (3), and seal the electronic functional module (3). S5. Place the cubic piezoelectric core (2) into the mounting cavity of the outer aggregate-shaped encapsulation shell (1), and perform potting, bonding and outer surface protection treatment to obtain a complete road-embedded wireless smart aggregate.

9. A method for preparing a road surface embedded wireless smart aggregate integrating sensing and energy harvesting as described in claim 8, characterized in that, In S3, a temperature measuring unit (36) and an inertial measuring unit (37) are also installed inside the cubic shell (21).

10. A road structure health monitoring system, characterized in that, The system includes a roadside data gateway and wireless smart aggregates based on any one of claims 9. Multiple wireless smart aggregates are embedded inside the road surface structure and acquire electrical energy generated by vehicle load and road vibration through piezoelectricity. The newly acquired voltage output information, temperature information, acceleration information and energy state information are wirelessly transmitted to the roadside data gateway.

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