A smart wearable sensing system and method based on flexible metasurface

Abstract

The application discloses a kind of intelligent wearable sensing system and method based on flexible metasurface.The one end of the one-dimensional periodic structure of the metasurface of the intelligent wearable sensing system is attached to the C-shaped ring, and the C-shaped ring, signal transmitter and signal receiving processor are electrically connected.The method comprises the following steps: attaching the one-dimensional periodic structure of the metasurface to the human body;transmitting radio frequency signals as standard signals by radio frequency signal transmitting circuit without action;transmitting radio frequency signals as to-be-detected signals when performing action, outputting reflection coefficient after analysis and comparison;obtaining the corresponding preset gesture action according to the reflection coefficient, transmitting it to the external intelligent device as the judgment result, and realizing the judgment of human body gesture action.The application of the system and method to metasurface material can confine electromagnetic waves on the surface of propagation, better confine energy, reduce loss, thereby increase the sensitivity of electromagnetic detection, and can be used for disabled people assistance, sports health monitoring and other aspects, and has good application value.

Description

Technical Field

[0001] This invention relates to an intelligent wearable sensing system, specifically to an intelligent wearable sensing system and method based on a flexible metasurface that uses changes in electromagnetic signals to intelligently determine human posture and movement by utilizing a flexible metasurface material attached to the surface of clothing. Background Technology

[0002] The global demand for smart wearable devices is increasing. Existing wearable devices are mainly concentrated in watches, wristbands, and ear-worn devices, but they all suffer from limitations such as limited information provision, poor comfort, and susceptibility to interference. Furthermore, technologies for sensing different postures or movements of the human body also have their shortcomings. For example, infrared technology has poor detail resolution and high cost; multi-sensor technology, with its multi-node transmission and complex wiring, can affect information communication quality. Traditional radio frequency transmission materials suffer from significant energy loss and are not sensitive enough to electromagnetic detection. Summary of the Invention

[0003] To address the problems existing in the background art, the present invention provides an intelligent wearable sensing system and method based on flexible metasurfaces.

[0004] The technical solution adopted in this invention is:

[0005] I. A smart wearable sensing system based on flexible metasurfaces:

[0006] The intelligent wearable sensing system includes a metasurface one-dimensional periodic structure (1), a duplexer (4), a C-ring (5), a signal transmitter, and a signal receiver processor. One side of the metasurface one-dimensional periodic structure and one side of the C-ring are attached together. The common end of the duplexer is electrically connected to the C-ring. The input end of the duplexer is electrically connected to the signal transmitter. The signal transmitter is electrically connected to an external power supply device. The output end of the duplexer is electrically connected to the signal receiver processor. The signal receiver processor is wirelessly connected to an external intelligent device.

[0007] The described metasurface one-dimensional periodic structure includes a flexible conductive strip and several one-dimensional subwavelength units, each of which is uniformly spaced along the length of the same side of the flexible conductive strip. The metasurface one-dimensional periodic structure serves as a waveguide structure; the flexible conductive strip is specifically a conductive metal fabric strip. Both the C-shaped ring and the one-dimensional subwavelength units are sheet-like structures, with one side of the C-shaped ring attached to the first one-dimensional subwavelength unit at one end of the metasurface one-dimensional periodic structure. The one-dimensional subwavelength units can be Z-shaped or C-shaped sheet-like structures, and every two adjacent one-dimensional subwavelength units are directly connected or coupled together through the flexible conductive strip. The one-dimensional subwavelength units resonate at the radio frequency signal frequency.

[0008] The C-shaped ring and the one-dimensional subwavelength unit are specifically made of flexible metallic conductive material.

[0009] The signal transmitter includes a radio frequency signal transmitting circuit and a first amplifier. The output terminal of the radio frequency signal transmitting circuit is electrically connected to the input terminal of the first amplifier, and the output terminal of the first amplifier is electrically connected to the input terminal of the duplexer. The radio frequency signal transmitting circuit is electrically connected to an external power supply device.

[0010] The signal receiving processor includes a digital-to-analog converter, a signal intelligent analysis wireless communication device, and a second amplifier. The output of the duplexer is electrically connected to the input of the second amplifier, the output of the second amplifier is electrically connected to the input of the digital-to-analog converter, the output of the digital-to-analog converter is electrically connected to the input of the signal intelligent analysis wireless communication device, and the signal intelligent analysis wireless communication device is wirelessly connected to an external intelligent device.

[0011] The aforementioned intelligent signal analysis wireless communication device includes an information digitization circuit, an information analysis circuit, and a wireless communication circuit. The wireless communication circuit is wirelessly connected to an external intelligent device. The information digitization circuit sequentially inputs the signal from the intelligent signal analysis wireless communication device into the information analysis circuit and the wireless communication circuit, and then the wireless communication circuit wirelessly transmits it to the external intelligent device.

[0012] II. A method for judging human posture and movement in an intelligent wearable sensing system includes the following steps:

[0013] Step 1: Attach the other side of the metasurface one-dimensional periodic structure, where the individual one-dimensional subwavelength units are not arranged, to the skin or outer clothing of the human body whose posture and movement are to be detected. Specifically, it can be attached to clothing or skin surfaces with human movement characteristics, such as the arms and legs. When the human body is not moving, the radio frequency signal of the preset frequency band is transmitted through the radio frequency signal transmission circuit of the signal transmitter, and finally transmitted to the information analysis circuit of the signal intelligent analysis wireless communication device and stored as a standard signal.

[0014] Step 2: When the human body is moving, the radio frequency signal transmitting circuit of the signal transmitter transmits a radio frequency signal in a preset frequency band, which is eventually transmitted to the information analysis circuit of the signal intelligent analysis wireless communication device as the signal to be detected. The information analysis circuit analyzes and compares the standard signal and the signal to be detected and outputs the reflection coefficient. Electromagnetic signals on the one-dimensional periodic structure of the metasurface will have different phase and amplitude signal reflection changes at different frequencies.

[0015] Step 3: Based on the reflection coefficient range of several preset postures, determine the reflection coefficient within one of the reflection coefficient ranges to obtain the corresponding preset posture. Transmit the obtained preset posture to an external smart device via a wireless communication circuit as the current human posture judgment result, and finally realize the judgment of human posture.

[0016] In steps one and two, the radio frequency signal is transmitted through the radio frequency signal transmission circuit of the signal transmitter. A one-dimensional subwavelength unit and a C-shaped ring are attached to each other as a transceiver coupler. The radio frequency signal passes through the first amplifier and the duplexer in sequence, and then is coupled to the one-dimensional periodic structure of the metasurface via the transceiver coupler and transmitted to the other end of the one-dimensional periodic structure of the metasurface. The one-dimensional periodic structure of the metasurface then couples the radio frequency signal to the C-shaped ring through the transceiver coupler. After passing through the duplexer, the second amplifier and the digital-to-analog converter in sequence, the frequency and amplitude of the radio frequency signal are converted into digital information. The digital information is then transmitted to the information digitization circuit and information analysis circuit of the signal intelligent analysis wireless communication device for analysis and comparison.

[0017] In step two, the information analysis circuit analyzes and compares the standard signal and the signal to be detected, and then outputs the reflection coefficient, as follows:

[0018]

[0019] Where m represents the length from the point where the one-dimensional periodic structure of the metasurface is subjected to bending or pressure during human movement to the end of the one-dimensional periodic structure of the metasurface containing the transceiver coupler; Γ() represents the reflection coefficient during human movement; Z m Z0 represents the equivalent impedance of the one-dimensional periodic structure of the metasurface transmitting the signal to be detected when the human body is in motion; Z0 represents the equivalent impedance of the one-dimensional periodic structure of the metasurface transmitting the standard signal when the human body is not in motion; j represents a complex number; α represents the phase shift constant; and ι represents the length of the one-dimensional periodic structure of the metasurface.

[0020] For different postures or movements of the human body, the reflection coefficient of the reflected signal transmitted through the one-dimensional periodic metasurface structure is different. Based on the obtained reflection coefficient, the posture of the human body or the location of pressure can be determined.

[0021] The beneficial effects of this invention are:

[0022] The flexible metasurface material of this invention can transmit electromagnetic signals while also sensing points where the material is bent or under pressure. This flexible metasurface material, attached to the surface of clothing, can not only transmit information but also sense different postures or movements of the human body. The application of metasurface materials can confine electromagnetic waves to the surface for propagation, better confining energy, reducing loss, and thus increasing the sensitivity to electromagnetic detection. The system and method of this invention can be used in assistive devices for people with disabilities, sports and health monitoring, and other fields, and has significant application value. Attached Figure Description

[0023] Figure 1 This invention relates to a one-dimensional metasurface periodic structure;

[0024] Figure 2 This is a system structure diagram of the present invention;

[0025] Figure 3 This is a diagram illustrating the human posture and movement discrimination method of the present invention;

[0026] In the figure: 1. One-dimensional periodic structure of metasurface, 2. Radio frequency signal transmitting circuit, 3. First amplifier, 4. Duplexer, 5. C-ring, 6. Digital-to-analog converter, 7. Signal intelligent analysis wireless communication device, 8. Transceiver coupler, 9. Second amplifier. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 2 As shown, the intelligent wearable sensing system based on a flexible metasurface of the present invention includes a one-dimensional periodic structure 1 of the metasurface, a duplexer 4, a C-shaped ring 5, a signal transmitter, and a signal receiver processor. One side of the one-dimensional periodic structure 1 of the metasurface and one side of the C-shaped ring 5 are attached together. The common end of the duplexer 4 is electrically connected to the C-shaped ring 5. The input end of the duplexer 4 is electrically connected to the signal transmitter. The signal transmitter is electrically connected to an external power supply device. The output end of the duplexer 4 is electrically connected to the signal receiver processor. The signal receiver processor is wirelessly connected to an external intelligent device.

[0029] like Figure 1 As shown, the one-dimensional periodic structure 1 of the metasurface includes a flexible conductive strip and several one-dimensional subwavelength units, each of which is uniformly spaced along the length of the same side of the flexible conductive strip. The one-dimensional periodic structure 1 of the metasurface serves as a waveguide structure. The flexible conductive strip is specifically a conductive metal fabric strip. Both the C-shaped ring 5 and the one-dimensional subwavelength units are sheet-like structures. One side of the C-shaped ring 5 is attached to the first one-dimensional subwavelength unit at one end of the one-dimensional periodic structure 1 of the metasurface. The one-dimensional subwavelength units can be Z-shaped or C-shaped sheet-like structures. Every two adjacent one-dimensional subwavelength units are directly connected or coupled together through the flexible conductive strip. The one-dimensional subwavelength units resonate at the radio frequency signal frequency. The C-shaped ring 5 and the one-dimensional subwavelength units are specifically made of flexible conductive metal material.

[0030] The signal transmitter includes a radio frequency signal transmitting circuit 2 and a first amplifier 3. The output terminal of the radio frequency signal transmitting circuit 2 is electrically connected to the input terminal of the first amplifier 3, and the output terminal of the first amplifier 3 is electrically connected to the input terminal of the duplexer 4. The radio frequency signal transmitting circuit 2 is electrically connected to an external power supply device.

[0031] The signal receiving processor includes a digital-to-analog converter 6, a signal intelligent analysis wireless communication device 7, and a second amplifier 9. The output of the duplexer 4 is electrically connected to the input of the second amplifier 9, the output of the second amplifier 9 is electrically connected to the input of the digital-to-analog converter 6, the output of the digital-to-analog converter 6 is electrically connected to the input of the signal intelligent analysis wireless communication device 7, and the signal intelligent analysis wireless communication device 7 is wirelessly connected to an external intelligent device.

[0032] The signal intelligent analysis wireless communication device 7 includes an information digitization circuit, an information analysis circuit, and a wireless communication circuit. The wireless communication circuit is wirelessly connected to an external intelligent device. The information digitization circuit sequentially inputs the signal from the signal intelligent analysis wireless communication device 7 into the information analysis circuit and the wireless communication circuit, and then the wireless communication circuit wirelessly transmits it to the external intelligent device.

[0033] The human posture and movement judgment method of the intelligent wearable sensing system of the present invention includes the following steps:

[0034] Step 1: As Figure 3 As shown, the other side of the metasurface one-dimensional periodic structure 1, where each one-dimensional subwavelength unit is not arranged, is attached to the skin surface or outer clothing of the human body whose posture and movement are to be detected. Specifically, it can be attached to clothing or skin surfaces with human movement characteristics, such as arms and legs. When the human body is not moving, the radio frequency signal transmission circuit 2 of the signal transmitter transmits a radio frequency signal of a preset frequency band, which is finally transmitted to the information analysis circuit of the signal intelligent analysis wireless communication device 7 and stored as a standard signal.

[0035] Step 2: When the human body is in motion, the radio frequency signal transmitting circuit 2 of the signal transmitter transmits a radio frequency signal in a preset frequency band, which is eventually transmitted to the information analysis circuit of the signal intelligent analysis wireless communication device 7 as the signal to be detected. The information analysis circuit analyzes and compares the standard signal and the signal to be detected and outputs the reflection coefficient. The electromagnetic signal on the one-dimensional periodic structure 1 of the metasurface will have different phase and amplitude signal reflection changes at different frequencies.

[0036] In steps one and two, the radio frequency signal is transmitted through the radio frequency signal transmitting circuit 2 of the signal transmitter. A one-dimensional subwavelength unit and a C-shaped ring 5 are attached to each other as a transceiver coupler 8. The radio frequency signal passes through the first amplifier 3 and the duplexer 4 in sequence, and then is coupled to the one-dimensional periodic structure 1 of the metasurface via the transceiver coupler 8 and transmitted to the other end of the one-dimensional periodic structure 1 of the metasurface. The one-dimensional periodic structure 1 of the metasurface then couples the radio frequency signal to the C-shaped ring 5 through the transceiver coupler 8. After passing through the duplexer 4, the second amplifier 9 and the digital-to-analog converter 6 in sequence, the frequency and amplitude of the radio frequency signal are converted into digital information. The digital information is then transmitted to the information digitization circuit and information analysis circuit of the signal intelligent analysis wireless communication device 7 for analysis and comparison.

[0037] In step two, the information analysis circuit analyzes and compares the standard signal and the signal to be detected, and then outputs the reflection coefficient, as follows:

[0038]

[0039] Where m represents the length from the point where the one-dimensional periodic structure 1 of the metasurface is subjected to bending or pressure during human movement to the end where the transceiver coupler 8 is located on the one-dimensional periodic structure 1 of the metasurface; Γ() represents the reflection coefficient during human movement; Z m Z0 represents the equivalent impedance of the one-dimensional periodic structure 1 of the metasurface transmitting the signal to be detected when the human body is in motion; Z0 represents the equivalent impedance of the one-dimensional periodic structure 1 of the metasurface transmitting the standard signal when the human body is not in motion; j represents a complex number; α represents the phase shift constant; and ι represents the length of the one-dimensional periodic structure 1 of the metasurface.

[0040] Step 3: Based on the reflection coefficient range of several preset postures, determine the reflection coefficient within one of the reflection coefficient ranges to obtain the corresponding preset posture. Transmit the obtained preset posture to an external smart device via a wireless communication circuit as the current human posture judgment result, and finally realize the judgment of human posture.

[0041] For different postures or movements of the human body, the reflection coefficient of the reflected signal transmitted through the one-dimensional periodic metasurface structure 1 is different. Based on the obtained reflection coefficient, the posture of the human body or the location of pressure can be determined.

[0042] This invention's system and method utilize flexible metasurface materials attached to the surface of clothing to intelligently determine human posture and movement through changes in electromagnetic signals. It is low-cost and capable of multiple functions. By using metasurfaces to confine electromagnetic waves to the surface for propagation, energy is better contained, loss is reduced, and thus electromagnetic detection is more sensitive. Metasurfaces are two-dimensional artificial composite materials obtained by selecting and arranging subwavelength units of different structural sizes according to the phase and amplitude distribution required by relevant design, overcoming the limitations of traditional materials while maintaining their excellent performance.

Claims

1. A smart wearable sensing system based on a flexible metasurface, characterized in that: The device includes a one-dimensional periodic structure (1) of the metasurface, a duplexer (4), a C-ring (5), a signal transmitter, and a signal receiver processor. One side of the one-dimensional periodic structure (1) of the metasurface and one side of the C-ring (5) are attached together. The common end of the duplexer (4) is electrically connected to the C-ring (5). The input end of the duplexer (4) is electrically connected to the signal transmitter. The signal transmitter is electrically connected to an external power supply device. The output end of the duplexer (4) is electrically connected to the signal receiver processor. The signal receiver processor is wirelessly connected to an external smart device. The metasurface one-dimensional periodic structure (1) includes a flexible conductive strip and several one-dimensional subwavelength units. Each one-dimensional subwavelength unit is evenly spaced along the length direction of the same side of the flexible conductive strip. The C-shaped ring (5) and the one-dimensional subwavelength units are both sheet-like structures. One side of the C-shaped ring (5) is attached to the first one-dimensional subwavelength unit at one end of the metasurface one-dimensional periodic structure (1). The C-shaped ring (5) and the one-dimensional subwavelength unit are specifically made of flexible metallic conductive material.

2. The intelligent wearable sensing system based on a flexible metasurface according to claim 1, characterized in that: The signal transmitter includes a radio frequency signal transmitting circuit (2) and a first amplifier (3). The output of the radio frequency signal transmitting circuit (2) is electrically connected to the input of the first amplifier (3), and the output of the first amplifier (3) is electrically connected to the input of the duplexer (4). The radio frequency signal transmitting circuit (2) is electrically connected to an external power supply device.

3. The intelligent wearable sensing system based on a flexible metasurface according to claim 1, characterized in that: The signal receiving processor includes a digital-to-analog converter (6), a signal intelligent analysis wireless communication device (7), and a second amplifier (9). The output of the duplexer (4) is electrically connected to the input of the second amplifier (9), the output of the second amplifier (9) is electrically connected to the input of the digital-to-analog converter (6), the output of the digital-to-analog converter (6) is electrically connected to the input of the signal intelligent analysis wireless communication device (7), and the signal intelligent analysis wireless communication device (7) is wirelessly connected to an external intelligent device.

4. The intelligent wearable sensing system based on a flexible metasurface according to claim 3, characterized in that: The signal intelligent analysis wireless communication device (7) includes an information digitization circuit, an information analysis circuit, and a wireless communication circuit. The wireless communication circuit is wirelessly connected to an external intelligent device. The information digitization circuit inputs the signal from the signal intelligent analysis wireless communication device (7) into the information analysis circuit and the wireless communication circuit in sequence, and then the wireless communication circuit wirelessly transmits it to the external intelligent device.

5. The method for judging human posture and movement in an intelligent wearable sensing system according to any one of claims 1-4, characterized in that: The method includes the following steps: Step 1: Attach the other side of the metasurface one-dimensional periodic structure (1) without each one-dimensional subwavelength unit to the skin or outer clothing of the human body whose posture and movement are to be detected; when the human body is not moving, transmit the radio frequency signal of the preset frequency band through the radio frequency signal transmission circuit (2) of the signal transmitter, and finally transmit it to the information analysis circuit of the signal intelligent analysis wireless communication device (7) and store it as a standard signal. Step 2: When the human body is in motion, the radio frequency signal transmitting circuit (2) of the signal transmitter transmits a radio frequency signal in a preset frequency band, which is eventually transmitted to the information analysis circuit of the signal intelligent analysis wireless communication device (7) as the signal to be detected. The information analysis circuit analyzes and compares the standard signal and the signal to be detected and outputs the reflection coefficient. Step 3: According to the reflection coefficient range of each of the several preset posture actions, the reflection coefficient is determined to be within one of the reflection coefficient ranges, and the corresponding preset posture action is obtained. The obtained preset posture action is transmitted to the external intelligent device through the wireless communication circuit as the current human posture action judgment result, and finally the human posture action judgment is realized.

6. The method for judging human posture and movement in an intelligent wearable sensing system according to claim 5, characterized in that: In steps one and two, radio frequency signals are transmitted through the radio frequency signal transmitting circuit (2) of the signal transmitter. A one-dimensional subwavelength unit and a C-shaped ring (5) that are attached to each other are used as transceiver couplers (8). The radio frequency signals pass through the first amplifier (3) and the duplexer (4) in sequence, and then through the transceiver coupler (8) to couple the radio frequency signals to the one-dimensional periodic structure (1) of the metasurface and transmit them to the other end of the one-dimensional periodic structure (1) of the metasurface. Then, the one-dimensional periodic structure (1) of the metasurface couples the radio frequency signals to the C-shaped ring (5) through the transceiver coupler (8). Then, after passing through the duplexer (4), the second amplifier (9) and the digital-to-analog converter (6) in sequence, the radio frequency signals are converted into digital information. Then, the digital information is transmitted to the information digitization circuit and information analysis circuit of the signal intelligent analysis wireless communication device (7) in sequence for analysis and comparison.

7. The method for judging human posture and movement in an intelligent wearable sensing system according to claim 5, characterized in that: In step two, the information analysis circuit analyzes and compares the standard signal and the signal to be detected, and then outputs the reflection coefficient, as follows: in, The length from the point where the one-dimensional periodic structure (1) of the metasurface is subjected to bending or pressure to one end of the one-dimensional periodic structure (1) of the metasurface when the human body is performing an action. Represents the reflection coefficient when the human body is performing an action; The equivalent impedance of the one-dimensional periodic structure of the metasurface (1) for transmitting the signal to be detected when the human body is performing actions; The equivalent impedance of a one-dimensional periodic structure on a metasurface (1) for transmitting standard signals when the human body is inactive; To represent a complex number; Represents the phase shift constant; The length of the one-dimensional periodic structure (1) on the metasurface is indicated.

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