Specific absorption rate evaluation method and device based on dielectric dummy model in automobile

Abstract

The invention relates to the technical field of electromagnetic measurement, and discloses a specific absorption rate evaluation method and device based on a dielectric dummy model in an automobile. The dielectric dummy whole body model comprises a head, a trunk and lower limbs which are internally communicated; the whole body model is filled with tissue fluid; interstitial fluid altimeters are respectively arranged at the navel position and the chest position of the model; measuring assemblies are arranged at the head, the chest and the crotch of the model respectively; the measuring assembly comprises a tapping auxiliary rod arranged on the model, a cylindrical probe detection rod is arranged in the tapping auxiliary rod, and a gasket is arranged between the probe detection rod and the tapping auxiliary rod. Through in-vivo measurement based on the whole-body dielectric dummy, an innovative dynamic sealing structure and intelligent data correction, the accuracy, reliability and scene applicability of automobile electromagnetic safety evaluation in a real driving state are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic measurement technology, specifically to a method and apparatus for evaluating specific absorption rate based on a dummy model of dielectric material inside a car. Background Technology

[0002] With the rapid development of the automotive industry and the widespread adoption of new energy vehicles, vehicle electronic and electrical systems are becoming increasingly complex. The resulting impact of in-vehicle electromagnetic radiation on human health is gradually attracting public attention. Currently, domestic and international industry standards typically assess electromagnetic exposure by placing field strength probes at specific locations within the vehicle, such as measuring the field strength in frequently touched areas like seats and dashboards. However, these methods are essentially external measurements and cannot accurately reflect the distribution and absorption of electromagnetic fields within the human body. They are particularly difficult to assess the actual impact on sensitive groups such as pregnant women, children, and the elderly, exhibiting significant measurement errors and limitations in assessment.

[0003] To overcome the shortcomings of in vitro measurements, existing technologies have developed methods that use dielectric mannequins to simulate the human body and place sensors inside them to collect electromagnetic data. For example, patent CN120779114A proposes a vehicle electromagnetic data generation system and method. This system constructs a simulated human tissue fluid mannequin and implants detection probes in multiple locations, including the head, chest cavity, abdominal cavity, and limbs, thereby achieving an approximate measurement of the electromagnetic field strength inside the body, which is an improvement over traditional in vitro detection methods.

[0004] However, in-depth analysis reveals that even with such full-body dummy models, existing measurement methods essentially remain within the scope of localized measurements. While the system deploys probes at multiple locations on the dummy, actual testing and data analysis often involve independent scanning and isolated evaluation of each location, failing to effectively consider the mutual coupling and energy superposition effects of electromagnetic fields between different parts of the body in a complex electromagnetic environment. The interior of a car is a complex electromagnetic space formed by numerous radiation sources. After multiple reflections from the car body, electromagnetic waves provide comprehensive, all-around irradiation to the human body. The resulting biological effects are the result of the combined action of all tissues, rather than a simple summation of exposure values ​​from individual locations. This "seemingly full-body structure, but also fragmented" approach of existing technology ignores the inherent correlation of overall exposure, making it impossible to accurately assess the comprehensive impact of electromagnetic radiation on the human body.

[0005] Furthermore, this type of technology has serious shortcomings when dealing with dynamic testing scenarios in actual vehicle operation. Traditional testing scenarios are mostly static, while vehicles generate continuous vibrations during actual operation. Especially under typical dynamic testing conditions such as rapid acceleration and deceleration, this causes violent sloshing of the internal tissue fluid of the dummy. This not only places stringent requirements on the sealing design of the probe and poses a risk of leakage, but also causes severe fluctuations in measurement data due to the non-uniform impact of the liquid on the probe, greatly affecting the stability and accuracy of the measurement. Under the dual challenges of dynamic and complex radiation fields, existing technologies struggle to guarantee the reliability of local measurements and cannot accurately assess the overall exposure level of the whole body.

[0006] Therefore, the essential shortcomings of the existing technology are: on the one hand, it fails to address the deficiencies of "whole-body model, local measurement" at the system level, and cannot assess the comprehensive effect of electromagnetic fields throughout the whole body; on the other hand, the physical stability and data accuracy of the measurement system face severe challenges under the dynamic operating conditions of a vehicle. Summary of the Invention

[0007] The present invention aims to provide a method and apparatus for measuring specific absorption rate based on a dummy model of in-vehicle dielectric material, in order to solve the problems of insufficient accuracy and unreliability of existing vehicle electromagnetic radiation measurement results.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a specific absorption rate evaluation device based on an in-vehicle dielectric dummy model, comprising a full-body dielectric dummy model; the full-body dielectric dummy model includes an internally connected head, torso, and lower limbs; the full-body model is filled with tissue fluid; tissue fluid height gauges are respectively installed at the navel and chest cavity positions of the model; measuring components are respectively installed at the head, chest, and groin positions of the model; the measuring components include an opening auxiliary rod installed on the model, a cylindrical probe probe is installed inside the opening auxiliary rod, and a washer is installed between the probe probe and the opening auxiliary rod.

[0009] Meanwhile, this solution also provides a specific absorption rate evaluation method based on an in-vehicle dielectric dummy model, which is applied to the aforementioned specific absorption rate evaluation device based on an in-vehicle dielectric dummy model, and includes the following steps: S1, the whole-body model containing tissue fluid and assembled test probes is fixedly installed on the driver's seat of the car to be tested; and the operating status and communication conditions of the car to be tested are set. The operating states include stationary and moving states; the moving states include rapid acceleration and rapid deceleration states. S2, use a tissue fluid height gauge to observe and calculate whether the tissue fluid in the whole-body model is sufficient; if it is insufficient, replenish it until it is sufficient; S3, using the probe probe rod, obtains field strength data at three locations on the full-body model: head, chest, and groin. The SAR value within the frequency range of 60MHz to 6GHz is calculated using the specific absorptivity formula, and expressed as... ; In the formula, The conductivity of the dummy tissue fluid; The magnitude of the electric field at a certain location within the dummy human body; The density of the tissue fluid in the dummy; When the vehicle is in motion, the dwell time of the probe is increased during measurement, and multiple measurements are taken to obtain field strength data; field strength data that deviates significantly are discarded, and the arithmetic mean of the remaining field strength data is calculated to obtain the field strength value; S4. The obtained SAR value is compared with the standard value to assess the electromagnetic radiation safety.

[0010] The principles and advantages of this scheme are: This solution abandons the traditional method of conducting external measurements only inside the vehicle, employing a dielectric dummy model that highly resembles the electromagnetic properties of the human body. By placing the measurement probe directly inside the dummy model, electromagnetic field data that most closely resembles the internal tissues of a real human body can be obtained. This represents a fundamental leap from indirect inference to direct measurement, ensuring the biological authenticity of the data source. It eliminates the inherent errors caused by the difference in field strength between the external and internal systems, providing more realistic and reliable assessment results of human electromagnetic exposure and ensuring measurement accuracy.

[0011] Meanwhile, addressing the complex electromagnetic environment within a vehicle characterized by multi-source, multi-directional, and overall radiation, this invention abandons the localized human body model used in the communications field and constructs a complete whole-body dielectric dummy model. This model can simulate the absorption, reflection, and coupling effects of electromagnetic waves throughout the body, thereby systematically assessing the overall electromagnetic exposure level, which is more consistent with the actual physical processes in automotive scenarios in principle.

[0012] To address the challenge of tissue fluid sloshing caused by vehicle movement (especially rapid acceleration and deceleration), this solution incorporates an innovative dynamic leak-proof structure. This structure utilizes a specialized, elastic-plastic gasket, combined with a gradually tapering opening design on the translucent housing. This design ensures that as the probe is inserted deeper, the contact pressure between the gasket and the orifice wall continuously increases, creating a dynamic self-tightening seal. This mechanical principle guarantees the reliable airtightness of the measurement system even under severe shaking, providing a fundamental guarantee for dynamic testing. It ensures the sealing durability and data validity of long-term testing, making it an effective method for accurate measurements under real-world driving conditions.

[0013] Finally, to address data fluctuations caused by tissue fluid impact, this solution introduces a data correction algorithm based on statistical principles. By increasing the probe's dwell time at each measurement point and performing multiple samplings, significantly outliers are removed, and the remaining valid data are then arithmetically averaged. This data processing principle effectively filters out transient interference, extracts stable field strength characteristics, and significantly improves the reliability and accuracy of the final results. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the specific absorption rate evaluation device based on an in-vehicle dielectric dummy model according to the present invention. Figure 2 This is an internal structural diagram of the specific absorption rate evaluation device based on an automotive internal dielectric dummy model according to the present invention. Figure 3 This is a schematic diagram of the measurement component structure of the specific absorption rate evaluation device based on an automotive internal dielectric dummy model according to the present invention. Figure 4 This is a flowchart illustrating the specific absorption rate evaluation method based on an automotive in-vehicle dielectric dummy model according to the present invention. Figure 5 This is a schematic diagram showing the location for obtaining field strength data in the specific absorption rate evaluation method based on an in-vehicle dielectric dummy model according to the present invention.

[0015] The markings in the accompanying drawings include: head 1, measuring component 2, opening auxiliary rod 3, torso 4, lower limb 5, tissue fluid height gauge 6, abdomen 7, upper limb 8, lower limb 9, probe probe rod 10, elastic-plastic washer 11, assembly interface 12, solution chamber 13, first tissue fluid tube 14, and second tissue fluid tube 15. Detailed Implementation

[0016] The following detailed description illustrates the specific implementation method: The specific absorption rate (SAR) evaluation method and apparatus based on an in-vehicle dielectric dummy model in this embodiment can measure the field strength in the ultra-wideband frequency range of 60MHz to 6GHz at various locations within the complete dielectric dummy model under dynamic vehicle operating conditions using a measurement probe. The SAR value is obtained by calculating the specific absorption rate (SAR) using the accurate conductivity and density of the tissue fluid, and the electromagnetic safety of the body is assessed, thereby improving the accuracy and reliability of the measurement.

[0017] Option 1 Provides a specific absorption rate evaluation device based on an in-vehicle dielectric dummy model, as shown in the attached document. Figure 1As shown, a dielectric dummy full-body model is included. In this embodiment, the dielectric dummy full-body model (hereinafter referred to as the full-body model or model) simulates the appearance and shape of a real adult human body, with a height of 165±5cm, making it more realistic and detailed. The full-body model includes an internally connected head 1, torso 4, and lower limbs 5. The dielectric dummy full-body model uses an electromagnetically transparent material, that is, the dummy's outer shell is made of an electromagnetically transparent material to simulate real human skin. The relative permittivity is less than 5 in the range of 60MHz to 3GHz, and between 3 and 5 in the range of 3GHz to 6GHz. The tangent loss is less than 0.05. In this embodiment, the model's transparent material is stored at 5℃ to 40℃.

[0018] The head 1 and torso 4 are smoothly connected, resulting in a smooth and burr-free model surface. An interface is provided at the lower end of the torso 4 to match the lower limbs 5, and the connection is secured with bolts. In this embodiment, the bolts are also made of electromagnetically transparent material to ensure that the measurement of SAR values ​​of human tissue fluid is minimized.

[0019] An assembly interface 12 is also provided at the top of the head 1 for assembling the probe probe rod 10. In this embodiment, the probe can move up and down within a range of 5cm while remaining sealed and stable. The head 1 is easy to assemble and has sufficient durability to withstand repeated assembly and use with the body and the antenna.

[0020] In this embodiment, the whole-body model is filled with tissue fluid, and the head 1, torso 4 and lower limbs 5 are interconnected by tissue fluid tubes. The tissue fluid tubes are made of electromagnetically transparent material, and the total amount of tissue fluid in the head 1, torso 4 and lower limbs 5 is 3.5±0.5L, which allows the probe to contact the tissue fluid and ensures that the measurement requirements are met.

[0021] As attached Figure 2 As shown, solution chambers 13 are provided in the head 1, torso 4, and lower limbs 5, respectively, for filling with tissue fluid. A first tissue fluid tube 14 is provided at the connection between the head 1 and torso 4, connecting the tissue fluid in the head 1 and torso 4. A second tissue fluid tube 15 is provided at the connection between the torso 4 and lower limbs 5, connecting the tissue fluid in the torso 4 and lower limbs 5. This allows the tissue fluid in the entire whole-body model to be interconnected, enabling the model to realistically reflect the comprehensive effect of electromagnetic fields on the whole body. When the field strength of a certain local body part of the whole-body model is detected, because the whole-body model takes into account the influence of other body parts on electromagnetic waves, the detection result is closer to reality, reducing detection errors.

[0022] In this embodiment, the torso 4 includes the chest cavity, abdomen and upper limbs, and the lower limbs 5 include the thigh and calf. During testing, solution chambers can be selectively installed in the thigh and calf. If solution chambers are installed, the thigh and calf are also connected by tissue fluid tubes, that is, tissue fluid tubes are set at the joints for communication.

[0023] As attached Figure 1 As shown, tissue fluid level gauges 6 are installed at the navel and chest cavity positions of the full-body model. Because the full-body human model is more detailed and has a larger volume and weight, installation and fixation are more difficult, increasing the load-bearing factor. Furthermore, while filling tissue fluid into traditional, simple local models is easier, filling tissue fluid into the full-body human model is much more challenging. Therefore, tissue fluid level gauges were added to monitor the tissue fluid filling height in real time.

[0024] Measuring components 2 are respectively provided on the top of the model's head, the upper part adjacent to the chest, and the side adjacent to the crotch. In this embodiment, as shown in the attached... Figure 3 As shown, the measuring component 2 includes an opening auxiliary rod 3 mounted on the model, a probe detection rod 10 disposed within the opening auxiliary rod 3, and an elastic-plastic washer 11 disposed between the probe detection rod 10 and the opening auxiliary rod 3. In this embodiment, the opening auxiliary rod 3 is respectively positioned at the top of the head, the upper end close to the chest, and the side close to the groin, so that the probe detection rod 10 inserted inside can penetrate deep into the corresponding head, chest, and groin positions for measurement.

[0025] In this embodiment, the probe rod 10 is movable to flexibly meet the measurement position requirements.

[0026] The auxiliary rod 3 features a perforated outer shell with a gradually decreasing aperture from the outside in. A ring-shaped elastic-plastic washer is fitted onto the probe rod 10. In this embodiment, a leak-proof elastic-plastic washer 11 with elastic-plastic properties is specially designed and manufactured based on the diameter of the probe rod 10 and the size of the perforated outer shell. During use, the washer is inserted into the probe rod 10. As the probe penetrates deeper from the outside in, the contact between the elastic-plastic washer 11 and the perforated outer shell becomes increasingly tight, achieving both measurement and leak-proof performance.

[0027] Option 2 A method for measuring specific absorption rate based on an in-vehicle dielectric dummy model is provided, which is applied to the aforementioned specific absorption rate measuring device based on the in-vehicle dielectric dummy model, as shown in the attached figure. Figure 4 As shown, it includes the following steps: S0, before testing, the dielectric parameters (conductivity and relative permittivity) of the tissue fluid stored at room temperature are calibrated and measured to ensure that the measured values ​​are within 10% of the target values ​​of relevant domestic and international standards.

[0028] S1. The whole-body model containing tissue fluid and assembled test probes is fixedly installed on the driver's seat of the car to be tested, and the measuring device is prepared. At the same time, the operating status and communication conditions of the car to be tested are set.

[0029] In this embodiment, the operating states include stationary and moving states, with moving states including rapid acceleration and rapid deceleration. Specifically, the vehicle is set to either a stationary or moving state based on mainstream domestic and international standards for human electromagnetic exposure in the automotive field, as well as the vehicle testing requirements of third-party testing institutions. Simultaneously, the communication conditions are set according to the communication requirements of the vehicle electromagnetic radiation testing procedures for the Automotive Health Index. For SAR measurements within the human body in the 60MHz~6GHz range, the communication conditions play a major role, but the stationary or moving operating state also has an impact. This is because, in the moving state, especially during extremely short bursts of rapid acceleration and deceleration, the corresponding transient pulse waves, after Fourier transform, have numerous high-frequency components falling within the 60MHz~6GHz frequency range. Therefore, the moving state is more affected in the high-frequency band of 60MHz~6GHz than the stationary state.

[0030] S2, observe and calculate whether the tissue fluid in the whole-body model is sufficient using a tissue fluid height gauge; if insufficient, supplement until sufficient.

[0031] S3, using the movable probe probe 10, measures three locations within the dielectric dummy model containing tissue fluid: the head, chest, and groin. (See attached image.) Figure 5 As shown, the field strength data of the head, chest, and groin, or one of these locations, of the full-body model are obtained. The SAR value in the frequency range of 60MHz to 6GHz is calculated using the specific absorptivity formula and expressed as follows: ; In the formula, The conductivity of the dummy tissue fluid; The magnitude of the electric field at a certain location within the dummy human body; This refers to the density of the tissue fluid in the dummy.

[0032] In this embodiment, The commonly used unit is Siemens per meter (S / m). The commonly used unit is volts per meter (V / m). The commonly used unit is kilograms per cubic meter (kg / m³). 3 If SAR is used, then the commonly used unit for SAR is watts per kilogram (W / kg).

[0033] Meanwhile, when the vehicle is in motion, especially during rapid acceleration and deceleration tests, the tissue fluid sloshes significantly, causing varying impact speeds on the probe, which may lead to unstable measurement data. Therefore, in this embodiment, the probe dwell time is increased during measurement, and multiple measurements are performed to obtain field strength data. Field strength data that deviate significantly (e.g., exceeding 10% of the concentration value) are discarded, and the remaining field strength data are arithmetically averaged to obtain the field strength value. This process corrects the measurement data, thereby increasing the reliability, stability, and accuracy of the measurement.

[0034] In this embodiment, based on the 10s dwell time of the vehicle electromagnetic radiation evaluation procedure of the vehicle health index, the dwell time is increased to 10~15s.

[0035] S4. The obtained SAR value is compared with the standard value to assess the electromagnetic radiation safety.

[0036] In this embodiment, the obtained SAR value is compared with the SAR safety limit of national standards or relevant international standards to assess electromagnetic radiation safety.

[0037] After the test, corresponding measures are taken based on the test results. In this embodiment, if the test results meet the reference standard limits, it is considered safe for the human body, and the test ends. Otherwise, it is considered potentially dangerous to the human body, and methods such as shielding, grounding, filtering, using absorbing materials, and reducing the power of the communication signal source while meeting normal operating requirements are adopted to reduce the electromagnetic radiation level of the vehicle until the test results meet the reference standard limits, thus completing the test.

[0038] In this embodiment, by simulating a real human body using a dielectric dummy model, the probe can be used to perform measurements inside the dummy model. Compared with current external measurements without a human body, this method is more in line with actual working conditions, greatly reduces measurement errors, and improves measurement accuracy.

[0039] From the perspective of practical communication applications, current mainstream testing methods mostly measure radiation from localized body parts of dummy dummy models. These dummy models are characterized by a single, small radiation source and primarily localized radiation. However, automotive applications present a significant challenge. The human body is situated within the complex electromagnetic environment of a vehicle, exposed to multiple radiation sources from various directions. This results in numerous radiation sources in multiple directions, the large size of both the vehicle and the human body, and predominantly whole-body radiation. Therefore, the dielectric dummy model proposed in this solution is a more complete whole-body model, better reflecting the actual automotive environment. Furthermore, the interconnected internal tissue fluid better reflects the coupling relationships between internal tissues, making the data more realistic and ensuring more accurate measurements.

[0040] Besides routine tests when the car is stationary, measurements under conditions such as constant speed, acceleration, deceleration, or even rapid acceleration or deceleration will cause sloshing of the tissue fluid within the dielectric dummy model. Ensuring a leak-proof seal while the probe is inserted into the tissue fluid for measurement is a problem that needs to be solved. This invention specifically designs and manufactures a leak-proof gasket with elastic-plastic properties based on the diameter of the probe rod 10 and the size of the opening in the transparent shell. Furthermore, the size of the opening in the transparent shell gradually decreases from the outside to the inside. As the probe is inserted deeper, the contact between the gasket and the opening in the transparent shell becomes increasingly tight, achieving both measurement and leak-proof performance.

[0041] During measurement, the tissue fluid sloshes significantly when the car is running, especially during rapid acceleration and deceleration tests, causing varying impact speeds on the probe and potentially leading to unstable measurement data. This invention increases the probe's dwell time and performs multiple measurements. Significantly deviating data is discarded, and the remaining data are arithmetically averaged—a correction process—to increase the reliability, stability, and accuracy of the measurement, ensuring the reliability of the results.

[0042] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A specific absorption rate testing device based on an in-vehicle dielectric dummy model, characterized in that: The device includes a full-body dielectric dummy model; the full-body dielectric dummy model includes an internally connected head, torso, and lower limbs; the full-body model is filled with tissue fluid; tissue fluid height gauges are installed at the navel and chest cavity positions of the model; measuring components are installed at the head, chest, and groin positions of the model; the measuring components include an opening auxiliary rod installed on the model, a cylindrical probe probe is installed inside the opening auxiliary rod, and a washer is installed between the probe probe and the opening auxiliary rod.

2. The specific absorption rate evaluation device based on an in-vehicle dielectric dummy model according to claim 1, characterized in that: The opening auxiliary rod adopts a wave-transparent shell with an opening, the diameter of which gradually decreases from the outside to the inside; the washer is an annular elastic-plastic washer, which is sleeved on the probe detection rod.

3. The specific absorption rate evaluation device based on an in-vehicle dielectric dummy model according to claim 1, characterized in that: The total amount of tissue fluid in the head, trunk, and lower limbs was 3.5 ± 0.5 L.

4. The specific absorption rate evaluation device based on an in-vehicle dielectric dummy model according to claim 1, characterized in that: The tissue fluids of the head, torso, and lower limbs are interconnected via tissue fluid tubes; the tissue fluid tubes are made of electromagnetically transparent material.

5. The specific absorption rate evaluation device based on an in-vehicle dielectric dummy model according to claim 1, characterized in that: The dielectric dummy full-body model is made of electromagnetically transparent material; the torso and lower limbs are connected by bolts, and the bolts are also made of electromagnetically transparent material.

6. The specific absorption rate evaluation device based on an in-vehicle dielectric dummy model according to claim 1, characterized in that: Assembly interfaces are provided at the top of the head, the upper part close to the chest, and the side close to the crotch for assembling the measuring probe.

7. A method for evaluating the specific absorption rate based on a dummy model of in-vehicle dielectric material, characterized in that, The specific absorption rate evaluation device based on an automotive in-vehicle dielectric dummy model, as described in any one of claims 1-6, comprises the following steps: S1, the whole-body model containing tissue fluid and assembled test probes is fixedly installed on the driver's seat of the car to be tested; and the operating status and communication conditions of the car to be tested are set. The operating states include stationary and moving states; the moving states include rapid acceleration and rapid deceleration states. S2, use a tissue fluid height gauge to observe and calculate whether the tissue fluid in the whole-body model is sufficient; if it is insufficient, replenish it until it is sufficient; S3, using the probe probe rod, obtains field strength data at three locations on the full-body model: head, chest, and groin. The SAR value within the frequency range of 60MHz to 6GHz is calculated using the specific absorptivity formula, and expressed as... ； In the formula, The conductivity of the dummy tissue fluid; The magnitude of the electric field at a certain location within the dummy human body; The density of the tissue fluid in the dummy; When the vehicle is in motion, the dwell time of the probe is increased during measurement, and multiple measurements are performed to obtain field strength data; field strength data that deviates significantly are discarded, and the arithmetic mean of the remaining field strength data is calculated to obtain the field strength value; S4. The obtained SAR value is compared with the standard value to assess the electromagnetic radiation safety.

8. The method for evaluating specific absorption rate based on a dummy model of in-vehicle dielectric material according to claim 7, characterized in that: It also includes measuring the dielectric parameters of the tissue fluid before testing.

9. The method for evaluating specific absorption rate based on a dummy model of in-vehicle dielectric material according to claim 7, characterized in that: The dwell time is 10-15 seconds.

10. The method for evaluating specific absorption rate based on a dummy model of in-vehicle dielectric material according to claim 7, characterized in that: It also includes taking appropriate measures based on the test results after the test.

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