A magnetic coding unit material for road domain information used in autonomous driving and its preparation method

Abstract

This invention discloses a magnetic coding unit material for road area information used in autonomous driving and its preparation method. The magnetic coding unit material is made of asphalt, limestone, magnetic ceramics, and composite mineral powder. The mass of the asphalt is 5.1% of the sum of the masses of the limestone and composite mineral powder, and the mass of the magnetic ceramics is 10%-80% of the sum of the masses of the limestone and magnetic ceramics within the same gradation range. After being magnetized by a magnetizer, the material of this invention, combined with an onboard gaussmeter, can read the binary coding information of the road, achieving comprehensive, rapid, and efficient detection and identification of road area information. It has advantages such as low cost, high reliability, energy saving, and environmental protection, while also possessing good thermal stability, corrosion resistance, mechanical properties, and electromagnetic characteristics.

Description

Technical Field

[0001] This invention belongs to the field of road materials technology, specifically relating to a magnetic coding unit material for road area information used in autonomous driving and its preparation method. Background Technology

[0002] Since its inception, autonomous driving technology has garnered widespread attention. Autonomous vehicles possess five basic functions: localization, perception, control, planning, and system management. Accurate localization and perception are core to the realization of autonomous driving technology; using various onboard sensors to detect and acquire location and road information is a key focus and prerequisite. Currently, autonomous vehicles primarily acquire their own location information through the Global Positioning System (GNSS) and Inertial Navigation System (INS); and perceive surrounding environmental information through a limited range of sensors, including onboard cameras, LiDAR, mm-wave radar, and ultrasonic radar. Due to hardware and software limitations, current autonomous driving technology still faces some limitations, such as weak GNSS signals in closed areas leading to inaccurate vehicle positioning; the inertial navigation system (INS) failing to maintain positioning accuracy over extended periods; and poor recognition performance of onboard identification devices in extreme weather conditions like rain, snow, and fog. Relying solely on onboard sensors is insufficient to meet the road information perception needs of autonomous vehicles; therefore, upgrading and transforming traditional road surfaces is urgently needed to achieve higher levels of autonomous driving. Because static magnetic fields are unaffected by non-ferromagnetic media such as wind, rain, fog, ice, and snow, a new type of magnetic coding material is formed by replacing some aggregates and mineral powder in asphalt mixtures with ferromagnetic materials. This material has good magnetic properties, corrosion resistance, thermal stability, and mechanical properties, and can provide a medium basis for information storage and target interactive perception. Summary of the Invention

[0003] The purpose of this invention is to provide a magnetic coding unit material for road information used in autonomous driving and a method for preparing the same.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A magnetic coding unit material is made of bitumen, limestone, magnetic ceramics, and composite mineral powder.

[0006] The limestone has a particle size of 0.075–16 mm, the magnetic ceramic has a particle size of 2.36–13.2 mm, and the composite mineral powder is composed of limestone with a particle size <0.075 mm and magnetic ceramic with a particle size <0.075 mm.

[0007] The mass of the asphalt is 5.1% of the sum of the masses of limestone and composite mineral powder;

[0008] The mass of the magnetic ceramic is 10%-80% of the sum of the masses of limestone and magnetic ceramic within the same gradation range.

[0009] Furthermore, the asphalt is SBS modified asphalt.

[0010] Furthermore, the magnetic coding unit material adopts an AC-13 gradation form.

[0011] Furthermore, the gradation range of the limestone is: 13.2-16mm, 9.5-13.2mm, 4.75-9.5mm, 2.36-4.75mm, 1.18-2.36mm, 0.6-1.18mm, 0.3-0.6mm, 0.15-0.3mm, 0.075-0.15mm.

[0012] Furthermore, the gradation range of the magnetic ceramic is: 9.5~13.2mm, 4.75~9.5mm, 2.36~4.75mm.

[0013] The preparation method of the above-mentioned magnetic coding unit material includes the following steps:

[0014] Step 1: Sift the limestone and magnetic ceramics to the required gradation range and dry them for later use;

[0015] Step 2: Limestone with a particle size <0.075mm and magnetic ceramics with a particle size <0.075mm are mixed as composite mineral powder. The composite mineral powder, limestone with a gradation range of 0.075~16mm, and magnetic ceramics with a gradation range of 2.36~13.2mm are then mixed with asphalt in sequence to obtain a mixture.

[0016] Step 3: Pour the mixture obtained in Step 2 into the mold and compact it. After completion, demold the sample and allow it to cool.

[0017] Step 4: Cut the sample obtained in Step 3 to obtain the specimen;

[0018] Step 5: Magnetize the specimen using a magnetizing power source to obtain magnetic coding units.

[0019] Specifically, the gradation range of the limestone is: 13.2-16mm, 9.5-13.2mm, 4.75-9.5mm, 2.36-4.75mm, 1.18-2.36mm, 0.6-1.18mm, 0.3-0.6mm, 0.15-0.3mm, 0.075-0.15mm, <0.075mm.

[0020] Specifically, the gradation range of the magnetic ceramic is: 9.5~13.2mm, 4.75~9.5mm, 2.36~4.75mm, <0.075mm.

[0021] Furthermore, in step 3, compaction is carried out using a rotary compactor, with 125 compaction cycles, a vertical pressure of 600 kPa, and a rotation speed of 30 r / min.

[0022] Furthermore, in step 4, the specimen has a thickness of 5 cm and a diameter of 10 cm.

[0023] Beneficial effects

[0024] This invention provides a novel, efficient, convenient, environmentally friendly, inexpensive, and durable magnetic coding unit for autonomous vehicles to identify road information. Using the magnetic coding unit proposed in this invention, all road information (such as latitude and longitude, station numbers, speed limits, road alignment, number of lanes, etc.) can be binary encoded, with the N pole of the coding unit representing binary 0 and the S pole representing binary 1. Since the coding unit is a permanent magnet, its magnetic field has the significant advantage of being unaffected by any weather factors such as light, rain, fog, ice, and snow. Vehicles equipped with gaussmeters can easily and accurately detect the polarity of the coding units laid on the road surface. By arranging and combining the polarities of the coding units, the polarity information is converted into binary information, which is then decoded into road information, allowing the onboard computer to obtain the road information of the vehicle's current location. This method can greatly improve the problem of traditional autonomous vehicle onboard sensors (cameras, mm-wave radar, lidar, etc.) being severely affected by weather conditions, significantly improving the safety redundancy and technology readiness of autonomous vehicles.

[0025] The novel magnetic coding unit developed in this invention can generate an average surface magnetic field of 36.36-291.46 Gs, exhibiting excellent corrosion resistance and thermal stability. The novel magnetic coding unit with 60% ferrite ceramic doping can generate a magnetic flux density of 14.63%, with a detection range of 20-24 cm. Its dynamic modulus parameter differs from that of asphalt mixtures by approximately 30%, demonstrating mechanical properties compatible with asphalt pavements. The novel magnetic coding unit's excellent corrosion resistance, thermal stability, and mechanical properties compatible with asphalt pavements meet the operational requirements for long-term service in asphalt pavements under multi-dimensional influences and can provide real-time monitoring of the asphalt pavement's operational status. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the preparation process of the magnetic coding unit material of this invention.

[0027] Figure 2 This is a schematic diagram showing the magnetic field strength and polarity of a magnetized magnetic coding unit at a certain height, measured using an on-board gaussmeter. Detailed Implementation

[0028] The preferred embodiments of the present invention will now be described in detail with reference to specific examples. It should be understood that the following examples are given for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from its spirit and essence.

[0029] In the following examples, the mineral powder is limestone with a particle size of <0.075mm.

[0030] In the following examples, the rotary compactor used was purchased from Songyi Company.

[0031] In the following embodiments, the magnetizing power supply used is a MAG-15122 capacitor pulse magnetizing power supply.

[0032] In the following examples, the magnetic performance tester used is a TUNKIA TD8650 single-axis gaussmeter with a range of 0 to 30,000 g and an accuracy of 0.1 g.

[0033] In the following examples, the SBS modified bitumen, limestone, and mineral powder were supplied by Subote New Materials Co., Ltd.

[0034] In the following embodiments, the ferrite ceramics were supplied by Northern Rare Earth Magnetic Materials Co., Ltd.

[0035] In the following embodiments, the amounts of each raw material used are shown in the table below:

[0036] Comparative Example Example 1 Example 2 Example 3 Example 4 Example 5 13.2-16mm limestone (g) 344 344 344 344 344 344 9.5-13.2mm limestone (g) 1824 1641.6 1459.2 1094.4 729.6 364.8 9.5-13.2mm ferrite ceramics (g) 0 182.4 364.8 729.6 1094.4 1459.2 4.75-9.5mm limestone (g) 2232 2008.8 1785.6 1339.2 892.8 446.4 4.75-9.5mm ferrite ceramics (g) 0 223.2 446.4 892.8 1339.2 1785.6 2.36-4.75mm limestone (g) 1080 972 864 648 432 216 2.36-4.75mm ferrite ceramics (g) 0 108 216 432 648 864 1.18-2.36mm limestone (g) 640 640 640 640 640 640 0.6-1.18mm limestone (g) 584 584 584 584 584 584 0.3-0.6mm limestone (g) 456 456 456 456 456 456 0.15-0.3mm limestone (g) 216 216 216 216 216 216 0.075-0.15mm limestone (g) 192 192 192 192 192 192 <0.075mm limestone (g) 432 388.8 345.6 259.2 172.8 86.4 <0.075mm ferrite ceramic (g) 0 43.2 86.4 172.8 259.2 345.6 SBS modified bitumen (g) 408 408 408 408 408 408

[0037] Example 1

[0038] A vibrating screen is used to screen limestone to the required gradation range for asphalt mixtures. The limestone is screened to gradations of 13.2-16mm, 9.5-13.2mm, 4.75-9.5mm, 2.36-4.75mm, 1.18-2.36mm, 0.6-1.18mm, 0.3-0.6mm, 0.15-0.3mm, 0.075-0.15mm, and <0.075mm. Ceramic ferrite powder is screened to gradations of 9.5-13.2mm, 4.75-9.5mm, 2.36-4.75mm, and <0.075mm, partially replacing the limestone and mineral powder of the same gradation in the original asphalt mixture.

[0039] Weigh the following raw materials according to their mass: 7054.4g limestone (0.075~16mm), 513.6g ferrite ceramic powder (2.36~13.2mm), 432g composite mineral powder (43.2g <0.075mm ferrite ceramic powder, 388.8g ordinary mineral powder), and 408g SBS modified bitumen. Prepare the magnetic coding unit at 25℃ using the following preparation method. The ferrite ceramic powder content is 10%.

[0040] Reference Figure 1 The preparation method is as follows:

[0041] S1. Weigh each raw material according to the proportion of each group and dry them in an oven at 105℃;

[0042] S2. The dried raw materials obtained in S1 are mixed and stirred with SBS modified asphalt in sequence to obtain ferrite ceramic asphalt mixture;

[0043] S3. Pour the ferrite ceramic asphalt mixture obtained in S2 into the mold of a rotary compactor. Set the compaction cycle to 125 times, the vertical pressure to 600 kPa, and the rotation speed to 30 r / min. After compaction, demold the cylindrical sample and cool it for 48 hours.

[0044] S4. Cut the cylindrical sample obtained in step S3 into cylindrical specimens with a thickness of 5cm and a diameter of 10cm.

[0045] S5. The sample cut in step S4 is magnetized using a MAG-15122 capacitor pulse magnetization power supply to obtain a magnetic coding unit with a ferrite ceramic content of 10%.

[0046] Example 2

[0047] The following raw materials were weighed according to their respective weights: 6540.8g limestone (0.075~16mm), 1027.2g ferrite ceramic powder (2.36~13.2mm), 432g composite mineral powder (86.4g <0.075mm ferrite ceramic powder, 345.6g ordinary mineral powder), and 408g SBS modified bitumen. Magnetic coding units were prepared at 25℃ using the following method. The ferrite ceramic powder content was 20%.

[0048] Reference Figure 1 The preparation method is as follows:

[0049] S1. Weigh each raw material according to the proportion of each group and dry them in an oven at 105℃;

[0050] S2. The dried raw materials obtained in S1 are mixed and stirred with SBS modified asphalt in sequence to obtain ferrite ceramic asphalt mixture;

[0051] S3. Pour the ferrite ceramic asphalt mixture obtained in S2 into the mold of a rotary compactor. Set the compaction cycle to 125 times, the vertical pressure to 600 kPa, and the rotation speed to 30 r / min. After compaction, demold the cylindrical sample and cool it for 48 hours.

[0052] S4. Cut the cylindrical sample obtained in step S3 into cylindrical specimens with a thickness of 5cm and a diameter of 10cm.

[0053] S5. The sample cut in step S4 is magnetized using a MAG-15122 capacitor pulse magnetization power supply to obtain a magnetic coding unit with a ferrite ceramic content of 20%.

[0054] Example 3

[0055] The following raw materials were weighed according to their respective weights: 5513.6g limestone (0.075~16mm), 2054.4g ferrite ceramic powder (2.36~13.2mm), 432g composite mineral powder (172.8g <0.075mm ferrite ceramic powder, 259.2g ordinary mineral powder), and 408g SBS modified bitumen. Magnetic coding units were prepared at 25℃ using the following method. The ferrite ceramic powder content was 40%.

[0056] Reference Figure 1 The preparation method is as follows:

[0057] S1. Weigh each raw material according to the proportion of each group and dry them in an oven at 105℃;

[0058] S2. The dried raw materials obtained in S1 are mixed and stirred with SBS modified asphalt in sequence to obtain ferrite ceramic asphalt mixture;

[0059] S3. Pour the ferrite ceramic asphalt mixture obtained in S2 into the mold of a rotary compactor. Set the compaction cycle to 125 times, the vertical pressure to 600 kPa, and the rotation speed to 30 r / min. After compaction, demold the cylindrical sample and cool it for 48 hours.

[0060] S4. Cut the cylindrical sample obtained in step S3 into cylindrical specimens with a thickness of 5cm and a diameter of 10cm.

[0061] S5. The sample cut in step S4 is magnetized using a MAG-15122 capacitor pulse magnetization power supply to obtain a magnetic coding unit with a ferrite ceramic content of 40%.

[0062] Example 4

[0063] The following raw materials were weighed according to their respective weights: 4486.4g limestone (0.075~16mm), 3081.6g ferrite ceramic powder (2.36~13.2mm), 432g composite mineral powder (259.2g <0.075mm ferrite ceramic powder, 172.8g ordinary mineral powder), and 408g SBS modified bitumen. Magnetic coding units were prepared at 25℃ using the following method. The ferrite ceramic powder content was 60%.

[0064] Reference Figure 1 The preparation method is as follows:

[0065] S1. Weigh each raw material according to the proportion of each group and dry them in an oven at 105℃;

[0066] S2. The dried raw materials obtained in S1 are mixed and stirred with SBS modified asphalt in sequence to obtain ferrite ceramic asphalt mixture;

[0067] S3. Pour the ferrite ceramic asphalt mixture obtained in S2 into the mold of a rotary compactor. Set the compaction cycle to 125 times, the vertical pressure to 600 kPa, and the rotation speed to 30 r / min. After compaction, demold the cylindrical sample and cool it for 48 hours.

[0068] S4. Cut the cylindrical sample obtained in step S3 into cylindrical specimens with a thickness of 5cm and a diameter of 10cm.

[0069] S5. The sample cut in step S4 is magnetized using a MAG-15122 capacitor pulse magnetization power supply to obtain a magnetic coding unit with a ferrite ceramic content of 60%.

[0070] Example 5

[0071] The following raw materials were weighed according to their respective weights: 3459.2g limestone (0.075~16mm), 4108.8g ferrite ceramic powder (2.36~13.2mm), 432g composite mineral powder (345.6g <0.075mm ferrite ceramic powder, 86.4g ordinary mineral powder), and 408g SBS modified bitumen. Magnetic coding units were prepared at 25℃ using the following method. The ferrite ceramic powder content was 80%.

[0072] Reference Figure 1 The preparation method is as follows:

[0073] S1. Weigh each raw material according to the proportion of each group and dry them in an oven at 105℃;

[0074] S2. The dried raw materials obtained in S1 are mixed and stirred with SBS modified asphalt in sequence to obtain ferrite ceramic asphalt mixture;

[0075] S3. Pour the ferrite ceramic asphalt mixture obtained in S2 into the mold of a rotary compactor. Set the compaction cycle to 125 times, the vertical pressure to 600 kPa, and the rotation speed to 30 r / min. After compaction, demold the cylindrical sample and cool it for 48 hours.

[0076] S4. Cut the cylindrical sample obtained in step S3 into cylindrical specimens with a thickness of 5cm and a diameter of 10cm.

[0077] S5. The sample cut in step S4 is magnetized using a MAG-15122 capacitor pulse magnetization power supply to obtain a magnetic coding unit with a ferrite ceramic content of 80%.

[0078] Comparative Example

[0079] Weigh the raw materials according to the following mass: 7568g limestone (0.075~16mm), 432g ordinary mineral powder, and 408g SBS modified asphalt. Prepare asphalt mixture units at 25℃ according to the following preparation method.

[0080] Reference Figure 1 The preparation method is as follows:

[0081] S1. Weigh each raw material according to the proportion of each group and dry them in an oven at 105℃;

[0082] S2. The dried raw materials obtained in S1 are mixed and stirred with SBS modified asphalt in sequence to obtain asphalt mixture;

[0083] S3. Pour the ferrite ceramic asphalt mixture obtained in S2 into the mold of a rotary compactor. Set the compaction cycle to 125 times, the vertical pressure to 600 kPa, and the rotation speed to 30 r / min. After compaction, demold the cylindrical sample and cool it for 48 hours.

[0084] S4. Cut the cylindrical sample obtained in step S3 into cylindrical specimens with a thickness of 5cm and a diameter of 10cm to obtain asphalt mixture units without ferrite ceramics.

[0085] The performance of the magnetic coding units of Examples 1 to 5 and the asphalt mixture units of the comparative examples were tested. The performance testing methods are shown below, and the results are shown in Tables 1 and 2.

[0086] (1) Magnetic performance test: The magnetic flux density at a height of 10cm between the magnetic coding unit and the asphalt mixture unit was measured using a TUNKIA TD8650 single-axis gaussmeter.

[0087] (2) Corrosion resistance test: 5% NaCl solution and pH3 HCl solution were used. The experimental temperature was set at 20℃. The magnetic units were placed in the two solutions for 12 hours and 30 dry-wet cycles were performed. The magnetic flux density at a height of 10cm between the magnetic coding unit and the asphalt mixture unit was measured.

[0088] (3) Thermal stability test: One cycle includes the following four processes: room temperature holding process (20℃, 3h); heating process (20℃~60℃, 30min); high temperature holding process (60℃, 3h); cooling process (60℃~20℃, 30min). A total of 100 heating-cooling cycles of 20℃~60℃ were performed, and the magnetic flux density of the magnetic coding unit and the asphalt mixture unit at a height of 10cm was measured.

[0089] (4) Mechanical property testing: The dynamic modulus of the magnetic coding unit was tested using a UTM-25 universal testing machine. A cylindrical sample with a ferrite ceramic doping content of 60%, a diameter of 10 cm, and a height of 15 cm was selected. The dynamic modulus was measured under temperature conditions of -10℃, 5℃, 20℃, 35℃, and 50℃, and under loading frequency conditions of 25Hz, 10Hz, 5Hz, 1Hz, 0.5Hz, and 0.1Hz.

[0090] Table 1 Performance test results of magnetic coding unit materials and asphalt mixtures

[0091]

[0092] Table 2. Test results of mechanical properties of magnetic coding unit materials and asphalt mixtures.

[0093] Reduce frequency (Log(Hz)) 0 1 2 3 4 5 6 Example 4 3.44325 3.70064 3.89524 4.03061 4.11928 4.17506 4.20924 Comparative Example 3.58396 3.87454 4.09085 4.23484 4.32331 4.37493 4.40413

[0094] Test results show that with the increase of ferrite ceramic content, the magnetic flux density at the same height increases significantly, from 2.42 Gs (Example 1) to 22.4 Gs (Example 5) at a height of 10 cm. In the corrosion resistance test, after 30 dry-wet cycles, the magnetic flux density of Examples 1-5 remained almost unchanged, indicating that the magnetic coding unit material has good corrosion resistance. In the thermal stability test, after 100 heating-cooling cycles, the magnetic induction density of Examples 1-5 remained almost unchanged, indicating that the magnetic coding unit material has good thermal stability. Considering the vehicle chassis height and economic applicability, the optimal ferrite ceramic content for the magnetic coding unit material is recommended to be 60%. Therefore, comparing the dynamic modulus of Example 4 and the comparative example under the same frequency reduction, the test results show that the difference in dynamic modulus between Example 4 and the comparative example is only about 30%, indicating that the magnetic coding unit material has mechanical properties that match those of traditional asphalt mixtures.

Claims

1. A magnetic coding unit material, characterized in that, It is made of asphalt, limestone with a particle size of 0.075~16mm, magnetic ceramics with a particle size of 2.36~13.2mm, and composite mineral powder; the composite mineral powder is composed of limestone with a particle size of <0.075mm and magnetic ceramics with a particle size of <0.075mm. The mass of the asphalt is 5.1% of the sum of the masses of limestone with a particle size of 0.075~16mm, magnetic ceramics with a particle size of 2.36~13.2mm, and composite mineral powder; The mass of the magnetic ceramic is 60% of the sum of the masses of limestone and magnetic ceramic of the same gradation range; The magnetic coding unit material adopts an AC-13 gradation form; The gradation range of the limestone with a particle size of 0.075~16mm is: 13.2-16mm, 9.5-13.2mm, 4.75-9.5mm, 2.36-4.75mm, 1.18-2.36mm, 0.6-1.18mm, 0.3-0.6mm, 0.15-0.3mm, 0.075-0.15mm; The gradation range of the magnetic ceramic with a particle size of 2.36~13.2 mm is: 9.5~13.2 mm, 4.75~9.5 mm, and 2.36~4.75 mm; The method for preparing the magnetic coding unit material includes the following steps: Step 1: Sift the limestone and magnetic ceramics to the required gradation range and dry them for later use; Step 2: Mix limestone with a particle size <0.075mm and magnetic ceramics with a particle size <0.075mm to form a composite mineral powder. Then, mix the composite mineral powder, limestone with a gradation range of 0.075~16mm, and magnetic ceramics with a gradation range of 2.36~13.2mm with asphalt in sequence to obtain a mixture. Step 3: Pour the mixture obtained in Step 2 into the mold and compact it. After completion, demold the sample and allow it to cool. Step 4: Cut the sample obtained in Step 3 to obtain the specimen; Step 5: Magnetize the specimen using a magnetizing power supply to obtain magnetic coding units; The magnetic coding unit material is used to encode road information in binary form. The N pole of the coding unit represents binary 0 and the S pole represents binary 1. By arranging and combining the polarities of the coding units, the polarity information is converted into binary information and then decoded into road information. The on-board computer can then obtain the road information of the vehicle's current location.

2. The magnetic coding unit material according to claim 1, characterized in that, The asphalt is SBS modified asphalt.

3. The magnetic coding unit material according to claim 1, characterized in that, In step 3, compaction is carried out using a rotary compactor, with 125 compaction cycles, a vertical pressure of 600 kPa, and a rotation speed of 30 r / min.

4. The magnetic coding unit material according to claim 1, characterized in that, In step 4, the specimen has a thickness of 5cm and a diameter of 10cm.

Images