A Finger Posture Sensing Device and Method Based on Wireless Coupled Resonance

Abstract

The present invention discloses a finger gesture sensing device and method based on wireless coupled resonance. The device includes a wireless coupled coil assembly worn on a finger, a signal excitation and signal receiving coil installed on the back of the hand, and a high-frequency signal generating and reflected signal measuring module fixed on the arm; the signal excitation and signal receiving coil is connected to the high-frequency signal generating and reflected signal measuring module, the high-frequency signal generating part outputs a high-frequency alternating current signal, and is wirelessly coupled with multiple wireless coupled coils on the finger through the signal excitation and signal receiving coil; the high-frequency reflected signal measuring part measures the frequency and amplitude of the reflected signal received by the signal excitation and signal receiving coil, and obtains the instantaneous gesture of the finger at the coil installation position from the characteristics of the reflected signal. The present invention has little influence on the movement of the finger, does not require additional active sensors to be installed on the finger or complex wiring, and has the characteristics of simple system deployment, low cost and high flexibility.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency sensing, and particularly relates to a finger gesture sensing device and method based on wireless coupled resonance. Background Art

[0002] Tracking of hand movements and gesture recognition are indispensable in evaluating the functions of human hands, and they are widely used in fields such as medicine, sign language communication, and mechanical operations. One type of gesture tracking method irradiates the human hand non - contactively with visible light, infrared light, electromagnetic waves, etc., and takes pictures, and extracts human gestures through image - processing algorithms. Since no additional sensors are added to the hand or fingers, the non - contact method has little limitation on finger flexion and extension. However, the range of hand movement is often limited within the irradiation range of light sources, radars, etc., and the overlap between obstacles and tracked targets in the irradiation direction will greatly increase the uncertainty of such measurement results.

[0003] Another type of method is contact - type, where various sensors are set on fingers, palms or arms to monitor each finger or finger joint respectively. The contact - type gesture tracking technology is not restricted by the irradiation source, and users can move freely. In addition, if high - precision sensors are used, the tracking accuracy of gestures can be improved accordingly. However, existing contact - type gesture tracking technologies often require wearing gloves, embedding the sensor circuit board into the gloves and fixing it to the fingers, connecting it to the controller and power supply through cables, and each finger needs to receive signals separately. This makes the contact - type gesture tracking system bulky and the circuit complex, imposing limitations on the normal movement and flexibility of fingers. Summary of the Invention

[0004] To solve the problems in the background art, the present invention proposes a finger gesture sensing device and method based on wireless coupled resonance, including a wireless coupled coil assembly worn on the finger, a signal excitation and signal receiving coil installed on the back of the hand, and a high - frequency signal generating and reflected signal measuring module fixed on the arm, which has little impact on finger movement, does not require additional active sensors to be installed on the finger or complex wiring, and has the characteristics of simple system deployment, low cost, and high flexibility.

[0005] The specific technical solutions adopted by the present invention are as follows:

[0006] I. A finger gesture sensing device based on wireless coupled resonance

[0007] It includes a plurality of wireless coupled coil assemblies worn on finger joints, a signal excitation and signal receiving coil installed on the back of the hand, and a high - frequency signal generating and reflected signal measuring module fixed on the arm;

[0008] The high-frequency signal generation and reflected signal measurement module is connected to the signal excitation and signal reception coils; the high-frequency signal generation and reflected signal measurement module includes a high-frequency signal generation part and a high-frequency reflection measurement part. The high-frequency signal generation part emits a high-frequency alternating current signal with a frequency band in MHz - GHz through the signal excitation and signal reception coils, and the high-frequency reflection measurement part measures the frequency and amplitude of the reflected signal received by the signal excitation and signal reception coils within the operating frequency band from MHz to GHz.

[0009] Multiple wireless coupling coil assemblies are wirelessly coupled to the signal excitation and signal reception coils, and multiple wireless coupling coils are resonantly coupled to each other; each wireless coupling coil assembly mainly consists of a wireless coupling coil and a fixing band, and the wireless coupling coil is fixed on each phalanx of the finger to be tracked through the fixing band.

[0010] The high-frequency signal generation and reflected signal measurement module includes a ring coupler, a power amplifier, an up-conversion mixer, a down-conversion mixer, an analog-to-digital converter, a digital-to-analog converter, a control unit, a data output unit, a battery, a local oscillator, and a radio frequency switch.

[0011] In the high-frequency signal generation part, the control unit outputs a low-frequency signal, and the low-frequency signal from the digital-to-analog converter and the high-frequency signal generated by the local oscillator are mixed by the up-conversion mixer to generate a high-frequency alternating current signal; the high-frequency alternating current signal is amplified by the first power amplifier, and then output to the signal excitation and signal reception coils through the ring coupler and the radio frequency switch; a part of the high-frequency alternating current signal emitted by the high-frequency signal generation part through the signal excitation and signal reception coils is coupled to the wireless coupling coils, and a part is reflected at each wireless coupling coil.

[0012] In the high-frequency reflection measurement part, the reflected signal received by the signal excitation and signal reception coils is input to the second power amplifier after passing through the radio frequency switch and the ring coupler, amplified by the second power amplifier, down-converted to a low-frequency signal by the down-conversion mixer, and then input to the control unit through the analog-to-digital converter, and finally the data for attitude analysis is output to the computer through the data output unit.

[0013] The ring coupler is used for isolation between the high-frequency output signal and the high-frequency reflected signal; the battery provides power for each part of the circuit.

[0014] One or two wireless coupling coil assemblies are worn on each phalanx; the fixing band is sleeved on the phalanx of the finger, and the material of the fixing band is non-metallic; the wireless coupling coil is fixed on the fixing band, and its axis is parallel or perpendicular to the phalanx.

[0015] The resonant frequency ω of each of the said wireless coupling coils i needs to be within the frequency range of the high-frequency alternating current signal from MHz to GHz;

[0016] The resonant frequency ω of each wireless coupling coil i is obtained through the following calculation:

[0017] Number the signal excitation and signal reception coils as 0, and number the wireless coupling coils from the finger root to the fingertip as i, where i = 1, 2,..., N, and N is the number of wireless coupling coils on the tracked finger; then the mutual inductance between any two wireless coupling coils is and According to the positional relationship between two wireless coupling coils, calculate the mutual inductance between any two wireless coupling coils through Neumann’s formula which is determined by the position between two coils i1, i2, i.e., the distance and the relative tilt angle in the axial direction between the two coils i1, i2;

[0018] The impedance matrix of the signal excitation and signal reception coils and the wireless coupling coils on the finger is:

[0019]

[0020] where U0 is the output voltage of the high-frequency signal generation and reflected signal measurement module; I0,..., I N are the currents of each coil; Z0 is the impedance value of the signal excitation and signal reception coils; Z1 is the impedance value of the wireless coupling coil, Z1 = r1 + jωL1 + 1 / (jωC1), L1 is the equivalent inductance value of the wireless coupling coil, C1 is the parasitic capacitance value of the wireless coupling coil, ω is the alternating current signal frequency, and j is the complex impedance; M 0i represents the mutual inductance between the signal excitation and signal reception coils and the i-th wireless coupling coil, where i = 1, 2,..., N;

[0021] According to the impedance matrix, the resonant frequency ω of the i-th wireless coupling coil i is:

[0022]

[0023] If the resonant frequency ω of the wireless coupling coil i is not within the frequency range of the high-frequency alternating current signal, then adjust the resonant frequency ω by adjusting the number of turns of the wireless coupling coil, etc. i .

[0024] II. A finger gesture sensing method based on wireless coupling resonance using the above device

[0025] includes the following steps:

[0026] 1) Wear a wireless coupling coil assembly on the tracked finger knuckle. The high-frequency signal generation part outputs a high-frequency signal, which is transmitted to the wireless coupling coil on the tracked finger in a coupled manner through the signal excitation and signal receiving coils;

[0027] 2) The high-frequency reflection measurement part measures the frequency and amplitude of the reflected signal received by the signal excitation and signal receiving coils, denoted as G(ω, A), where ω is the frequency of the reflected signal and A is the corresponding amplitude of the reflected signal;

[0028] 3) Obtain the frequencies and amplitudes of all maximum points from the curve corresponding to the reflected signal G(ω, A), form a frequency characteristic equation y = f(ω, A), obtain the frequency characteristic closest to the current reflected signal by solving the optimization problem, and obtain the positions between the coils according to the closest frequency characteristic, thereby completing the acquisition of the finger posture.

[0029] The positions between the coils include the distance and relative inclination angle between the coils. The distance between the coils is the distance between the centers of two adjacent coils, and the relative inclination angle between the coils is the included angle between the central axes of two adjacent coils.

[0030] The specific steps of step 3) are as follows:

[0031] 3.1) Obtain the frequencies and amplitudes of all maximum points from the curve corresponding to the reflected signal G(ω, A), and form a frequency characteristic equation y = f(ω, A); the frequency of each maximum point is the resonance frequency ω of each wireless coupling coil i ;

[0032] Solve the optimization problem of the following formula based on the frequency characteristic equation to obtain the closest frequency characteristic F p (ω, A):

[0033]

[0034] where is the set of all frequency characteristics in the mutual inductance frequency characteristic dictionary;

[0035] 3.2) Construct a mutual inductance frequency characteristic dictionary;

[0036] 3.3) In the mutual inductance frequency characteristic dictionary, according to the closest frequency characteristic F p (ω, A), obtain the position relationship S p (d1,..., d N , θ1,..., θ N ) of each wireless coupling coil under the current reflected signal, where d i , θ i are the distance and relative inclination angle between the i-th and the (i - 1)-th coils respectively, i = 1,..., N;

[0037] Since the position of each coil on the finger is fixed after wearing, the finger posture can be obtained according to the positions S of the respective wireless coupling coils p (d1, ..., d N , θ1, ..., θ N ).

[0038] The specific content of step 3.2) is as follows:

[0039] According to the accuracy requirements of finger posture recognition, from curling to fully straightening, P different finger postures are defined, and the position relationships of the respective wireless coupling coils corresponding to each finger posture are denoted as:

[0040] S p (d1, ..., d N , θ1, ..., θ N ), p = 1, 2, ..., P;

[0041] After wearing the sensing device, system calibration is performed, the reflected signals of P postures are measured, and the frequencies and amplitudes of the maximum points are extracted. The sets of frequency characteristic equations F(ω, A) corresponding to all postures are combined into a set According to the finger posture and the corresponding frequency characteristics, a mutual inductance frequency characteristic dictionary is obtained, specifically:

[0042]

[0043] When tracking multiple fingers, wireless coupling coil assemblies need to be worn on all the tracked fingers, and signal excitation and signal receiving coils corresponding to each tracked finger are installed on the back of the hand. Each finger corresponds to a signal excitation and signal receiving coil;

[0044] Each signal excitation and signal receiving coil is connected to a ring coupler through a radio frequency switch, and then enters the subsequent circuit of the high-frequency signal generation and reflected signal measurement module; the radio frequency switch switches between the respective signal excitation and signal receiving coils, and only one signal excitation and signal receiving coil is conducted at the same time; after identifying the instantaneous posture of each finger, the postures of all the tracked fingers are combined to complete gesture recognition.

[0045] The beneficial effects of the present invention are as follows:

[0046] 1) The present invention utilizes the principle of wireless coupling between coils, fixes wireless coupling coils on the fingers, obtains the resonant state of the wireless coupling coils by measuring the frequency amplitude characteristics of the working frequency band of the reflected signals, and thereby infers the relative positions and inclinations between the coils, so as to obtain the instantaneous posture of the fingers. If multiple fingers are tracked simultaneously and the instantaneous postures of the fingers are combined, gesture recognition can be achieved.

[0047] 2) The system of the present invention does not require additional active sensors to be installed on the fingers or complex wiring, does not affect the normal activities of the fingers or reduce finger functions, and has simple system deployment and high flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic structural diagram of the system of the present invention for tracking a single finger.

[0049] Figure 2 is a schematic diagram of the working principle of the high-frequency signal generation and reflected signal measurement module of the present invention.

[0050] Figure 3 is a schematic diagram of the relative positions of the wireless coupling coils of the system of the present invention in two different finger postures.

[0051] Figure 4 is a schematic structural diagram of the system of the present invention for tracking multiple fingers.

[0052] In the figure: wireless coupling coil assembly 1, wireless coupling coil 101, fixing band 102, signal excitation and signal receiving coil 2, high-frequency signal generation and reflected signal measurement module 3, ring coupler 301, power amplifier 302, up-conversion mixer 303, down-conversion mixer 304, analog-to-digital converter 305, digital-to-analog converter 306, control unit 307, data output unit 308, battery 309, local oscillator 310, and radio frequency switch 311. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0053] The present invention will be described in detail below with reference to the drawings and embodiments.

[0054] As Figure 1 shown, the present invention includes a wireless coupling coil assembly 1 worn on the finger, a signal excitation and signal receiving coil 2 installed on the back of the hand, and a high-frequency signal generation and reflected signal measurement module 3 fixed on the arm. The signal excitation and signal receiving coil 2 is connected to the high-frequency signal generation and reflected signal measurement module 3. The high-frequency signal generation part of the high-frequency signal generation and reflected signal measurement module 3 generates high-frequency alternating current signals in a certain frequency band (100 MHz - 5 GHz) and outputs them to the signal excitation and signal receiving coil 2. The signal excitation and signal receiving coil 2 is coupled with the wireless coupling coil 101 worn on the finger joint, and the wireless coupling coils 101 are resonantly coupled with each other. The high-frequency reflection measurement part of the high-frequency signal generation and reflected signal measurement module 3 measures the frequency and amplitude of the reflected signals at the working frequency band at the signal excitation and signal receiving coil 2, and infers the instantaneous posture of the finger from the characteristics of the reflected signals.

[0055] The wireless coupling coil assembly 1 is composed of a wireless coupling coil 101 and a fixing band 102. The material of the fixing band 102 is non-metal. The wireless coupling coil 101 is fixed to the phalanx of the finger to be tracked by the fixing band, and one or two wireless coupling coil assemblies are worn on each phalanx. Figure 1 The axis of the shown wireless coupling coil is parallel to the phalanx of the finger where it is located. And the axis of the wireless coupling coil can be parallel to the phalanx where it is located or perpendicular to the phalanx.

[0056] As Figure 2 As shown, the high-frequency signal generation and reflected signal measurement module 3 includes a ring coupler 301, a power amplifier 302, an up-conversion mixer 303, a down-conversion mixer 304, an analog-to-digital converter 305, a digital-to-analog converter 306, a control unit 307, a data output unit 308, a battery 309, a local oscillator 310, and a radio frequency switch 311. The radio frequency switch 311 forms two branches through the ring coupler 301, a branch of the high-frequency signal generation part and a branch of the high-frequency reflection measurement part; the branch of the high-frequency signal generation part includes a first power amplifier 302, an up-conversion mixer 303, and a digital-to-analog converter 306 connected in sequence, and the local oscillator 310 connected to the control unit 307 is connected to the up-conversion mixer 303; the branch of the high-frequency reflection measurement part includes a second power amplifier 302, a down-conversion mixer 304, an analog-to-digital converter 305, and the digital-to-analog converter 306 and the analog-to-digital converter 305 are connected to the data output unit 308 through the control unit 307.

[0057] In the high-frequency signal generation part, the control unit 307 outputs a low-frequency signal, which is mixed with the high-frequency signal generated by the local oscillator 310 through the up-conversion mixer 303 by the digital-to-analog converter 306 to generate a high-frequency alternating current signal, which is amplified by the power amplifier 302 and output to the signal excitation and signal receiving coil 2 for outward transmission. A part of the high-frequency alternating current signal is coupled with the wireless coupling coil 101, and a part is reflected. The reflected signal is measured by the high-frequency reflection measurement circuit of the high-frequency signal generation and reflected signal measurement module 3. In the high-frequency reflection measurement part, the reflected signal is amplified by the power amplifier 302, down-converted to a low-frequency signal by the down-conversion mixer 304, sent to the control unit 307 through the analog-to-digital converter 305, and finally the reflected signal is output through the data output unit 308 for subsequent data processing. The control unit 307 controls and schedules the functions of each part of the circuit. The ring coupler 301 is used for the isolation between the high-frequency output signal and the high-frequency reflected signal. The battery 309 provides power for each part of the circuit.

[0058] Combined Figure 1 and Figure 3, under the excitation of a high-frequency alternating current signal, the signal excitation and signal receiving coil 2 are coupled with the wireless coupling coil 101 on the finger, and the wireless coupling coils 101 are resonantly coupled with each other. The impedance value of the signal excitation and signal receiving coil is Z0, and the impedance value of the wireless coupling coil 101 fixed on the finger is Z1, Z1 = r1 + jωL1 + 1 / (jωC1), where r1 is the resistance value of the wireless coupling coil 101, L1 is the equivalent inductance value, C1 is the parasitic capacitance value, ω is the alternating current signal frequency, and j is the complex impedance. The signal excitation and signal receiving coil 2 is numbered 0, and the wireless coupling coils 101 are numbered i from the finger root to the fingertip, i = 1, 2,..., N, where N is the number of wireless coupling coils 101 on this finger. Then the mutual inductance between any two wireless coupling coils is and determined by the distance and the relative inclination angle of the axes between two coils i1 and i2; according to the positional relationship between two wireless coupling coils, the mutual inductance between any two wireless coupling coils is calculated through Neumann's formula determined by the position between two coils i1 and i2, that is, the distance and the relative inclination angle of the axes between two coils i1 and i2;

[0059] Under the excitation of a high-frequency signal, the impedance matrix of the signal excitation and signal receiving coil 2 and the wireless coupling coil 101 on the finger is:

[0060]

[0061] where U0 is the output voltage of the high-frequency signal generation and reflected signal measurement module 3, and I0,..., I N are the currents of each coil. Z0 is the impedance value of the signal excitation and signal receiving coil 2; Z1 is the impedance value of the wireless coupling coil (101), Z1 = r1 + jωL1 + 1 / (jωC1), L1 is the equivalent inductance value of the wireless coupling coil, C1 is the parasitic capacitance value of the wireless coupling coil, and M 0i represents the mutual inductance between the signal excitation and signal receiving coil and the i-th wireless coupling coil, i = 1, 2,..., N;

[0062] According to the impedance matrix, the resonant frequency ω of the i-th (i = 1, 2,..., N) wireless coupling coil 101 i is:

[0063]

[0064] Measure the reflected signal G(ω, A), extract the frequency and amplitude of the extreme points from it, and form the frequency characteristic equation y = f(ω, A). The mutual inductance values between the excitation coil and each wireless coupling coil corresponding to the current posture can be obtained through the following optimization problem:

[0065]

[0066] where, is the frequency characteristic in the mutual inductance frequency characteristic dictionary.

[0067] (Equation (1)) determines which frequency characteristic F the currently measured reflected signal is closest to by calculating the minimum value of the norm 2 between the obtained f(ω, A) and each frequency characteristic F(ω, A) calibrated in the mutual inductance frequency characteristic dictionary. According to the closest frequency characteristic F p (ω, A), obtain the positional relationship S p (d1,..., d N , θ1,..., θ N ) of each wireless coupling coil under the current reflected signal. Since the position of each coil on the finger is fixed after wearing, the finger posture can be obtained from the positional relationship.

[0068] The mutual inductance frequency characteristic dictionary is established through the system calibration performed first after wearing the device. According to the accuracy requirements of finger posture recognition, define P different finger postures from curling to fully straightening. The positional relationship of each wireless coupling coil corresponding to each finger posture is denoted as: S p (d1,..., d N , θ1,..., θ N ), p = 1, 2,..., P;

[0069] After wearing the sensing device, perform system calibration, measure the reflected signals of P postures and extract the frequency and amplitude of the maximum points. The sets of frequency characteristic equations F(ω, A) corresponding to all postures are formed into a set According to the finger posture and the corresponding frequency characteristics, obtain the mutual inductance frequency characteristic dictionary, specifically:

[0070]

[0071]

[0072] Since the position of each coil on the finger is fixed after wearing, the finger posture can be obtained from the positional relationship S(d1,..., d N , θ1,..., θ N ).

[0073] In the case of tracking multiple fingers, a wireless coupling coil assembly needs to be worn on each finger to be tracked, and signal excitation and signal reception coils corresponding to the fingers are installed on the back of the hand. After identifying the instantaneous postures of each finger, the fingers can be combined to complete gesture recognition.

[0074] Each finger corresponds to a signal excitation and signal reception coil. The signal excitation and signal reception coils are connected to a ring coupler through a radio frequency switch and then enter the subsequent circuits of the high-frequency signal generation and reflected signal measurement module. The radio frequency switch switches between the signal excitation and signal reception coils. Only one signal excitation and signal reception coil is conducted at the same time, that is, the posture of only one finger is recognized at the same time.

[0075] The specific implementation of the present invention is as follows:

[0076] As Figure 1 shown, the high-frequency signal generation and reflected signal measurement module 3 fixed on the arm generates high-frequency alternating current signals in a certain frequency band and transmits them through the signal excitation and signal reception coils 2. The signal excitation and signal reception coils 2 are coupled with the wireless coupling coils 101 worn on the fingers, and the wireless coupling coils 101 resonate and couple with each other. The impedance value of the signal excitation and signal reception coil 2 is set to Z0, and the impedance value of the wireless coupling coil 101 is Z1, Z1 = r1 + jωL1 + 1 / (jωC1), where r1 is the resistance value of the wireless coupling coil 101, L1 is the equivalent inductance value, C1 is the parasitic capacitance value, and ω is the frequency of the alternating current signal.

[0077] As Figure 2 shown, the control unit 307 of the high-frequency signal generation and reflected signal measurement module 3 outputs a low-frequency signal, which is mixed with the high-frequency signal generated by the local oscillator 310 through the up-conversion mixer 303 by the digital-to-analog converter 306 to generate a high-frequency alternating current signal of 100 MHz - 5 GHz. The high-frequency alternating current signal is amplified by the power amplifier 302 and output to the signal excitation and signal reception coils 2. A part of the high-frequency alternating current signal is coupled with the wireless coupling coil 101, and a part is reflected. The reflected signal is amplified by the power amplifier 302 and then down-converted to a low-frequency signal through the down-conversion mixer 304, passed through the analog-to-digital converter 305 to the control unit 307, and finally output through the data output unit 308 for subsequent data processing. The control unit 307 controls and schedules the functions of each part of the circuit. The ring coupler 301 is used for isolation between the high-frequency output signal and the high-frequency reflected signal. The battery 309 provides power for each part of the circuit.

[0078] The signal excitation and signal receiving coil 2 are numbered 0, and each wireless coupling coil 101 is numbered i from the root to the tip of the finger, where i = 1, 2,..., N, and N is the number of wireless coupling coils 101 on the finger. Each finger joint can wear one or two wireless coupling coil assemblies. As Figure 3 shown, one wireless coupling coil assembly 1 is worn on each of the first and third finger joints of the finger, and 2 wireless coupling coil assemblies are worn on the second finger joint. Therefore, N = 4. The mutual inductance between any two coils is and determined by the distance and the relative inclination angle in the axial direction between two coils i1 and i2;

[0079] Under high-frequency signal excitation, the impedance matrix of the signal excitation and signal receiving coil 2 and the wireless coupling coils 101 on the finger is:

[0080]

[0081] where U0 is the output voltage of the high-frequency signal generation and reflected signal measurement module 3, and I0,..., I4 are the currents of each coil.

[0082] The resonance frequency ω of the i-th (i = 1, 2, 3, 4) wireless coupling coil 101 i is:

[0083]

[0084] As Figure 3 in finger posture 1 and finger posture 2 of the finger, when the finger posture changes, the relative positions of the wireless coupling coils 101 change, and the resonance frequencies of the wireless coupling coils 101 also change accordingly. According to the required finger posture recognition accuracy, the finger postures from curled to fully extended are roughly evenly divided into 7 types. After wearing the device, system calibration is first performed, and the positional relationship of each wireless coupling coil corresponding to each finger posture is recorded as:

[0085] S p (d1,..., d4, θ1,..., θ4), p = 1, 2,..., 7;

[0086] Measure the reflected signals of 7 postures and extract the frequencies and amplitudes of the extreme points respectively to form the frequency characteristic equation F(ω, A). Establish the following mutual inductance frequency characteristic dictionary:

[0087]

[0088] Measure the reflected signal G(ω, A) and obtain the frequencies and amplitudes of all extreme points in the corresponding curve to form the frequency characteristic equation y = f(ω, A). Solve the optimization problem to obtain the frequency characteristic F that is closestp (ω, A):

[0089]

[0090] wherein, is the frequency feature in the mutual inductance frequency feature dictionary.

[0091] In the mutual inductance frequency feature dictionary, according to the calculated frequency feature F p (ω, A), obtain the positional relationship S(d1,..., d4, θ1,..., θ4) of the wireless coupling coils, where d i , θ i , i = 1,..., 4 are respectively the distance between the i-th and the (i - 1)-th coils and the included angle between the central axes of the coils. Since the position of each coil on the finger is fixed after wearing, the finger gesture can be obtained from the positional relationship S(d1,..., d4, θ1,..., θ4).

[0092] As Figure 4 shown, when tracking multiple fingers, a wireless coupling coil assembly 1 needs to be worn on each finger to be tracked, and for each finger, a signal excitation and signal receiving coil 2 needs to be installed on the back of the hand. The signal excitation and signal receiving coil 2 is connected to the ring coupler 301 through the RF switch 311, and then enters the subsequent circuit of the high-frequency signal generation and reflected signal measurement module 3. The RF switch 311 switches between the signal excitation and signal receiving coils 2 at a speed of 100 times per second, and only one signal excitation and signal receiving coil 2 is turned on at the same moment. That is, only the gesture of one finger is recognized at the same moment. Since the switching speed of the RF switch 311 is 10 ms, the user gesture obtained by combining the instantaneous gestures of each finger recognized in sequence can meet the gesture recognition requirements.

Claims

1. A finger gesture sensing device based on wireless coupled resonance, characterized in that: It includes a plurality of wireless coupling coil assemblies (1) worn on finger knuckles, a signal excitation and signal receiving coil (2) mounted on the back of the hand, and a high-frequency signal generating and reflected signal measuring module (3) fixed on the arm; The high-frequency signal generating and reflected signal measuring module (3) is connected to the signal excitation and signal receiving coil (2); the high-frequency signal generating and reflected signal measuring module (3) includes a high-frequency signal generating part and a high-frequency reflection measuring part. The high-frequency signal generating part emits a high-frequency alternating current signal with a frequency band in MHz - GHz through the signal excitation and signal receiving coil (2), and the high-frequency reflection measuring part measures the frequency and amplitude of the reflected signal received by the signal excitation and signal receiving coil (2) within the operating frequency band from MHz to GHz; The plurality of wireless coupling coil assemblies (1) are wirelessly coupled to the signal excitation and signal receiving coil (2), and the plurality of wireless coupling coils (101) are resonantly coupled to each other; each wireless coupling coil assembly (1) is mainly composed of a wireless coupling coil (101) and a fixing band (102), and the wireless coupling coil (101) is fixed on each knuckle of the finger to be tracked through the fixing band (102); The resonant frequency ω of each of the wireless coupling coils i needs to be within the frequency range of high-frequency AC signals in MHz - GHz; The resonant frequency ω of each wireless coupling coil i is obtained by the following calculation: The signal excitation and signal receiving coil (2) are numbered 0, and the wireless coupling coils (101) are numbered i from the base to the tip of the finger, where i = 1, 2, …, N, and N is the number of wireless coupling coils (101) on the traced finger. Then the mutual inductance between any two wireless coupling coils is and According to the positional relationship between two wireless coupling coils, the mutual inductance between any two wireless coupling coils is calculated by the Neumann formula The impedance matrix of the signal excitation and signal receiving coil (2) and the wireless coupling coil (101) on the finger is: Among them, U0 is the output voltage of the high-frequency signal generation and reflected signal measurement module (3); I0, …, I N are the currents of each coil; Z0 is the impedance value of the signal excitation and signal reception coil (2); Z1 is the impedance value of the wireless coupling coil (101), Z1 = r1 + jωL1 + 1 / (jωC1), L1 is the equivalent inductance value of the wireless coupling coil, C1 is the parasitic capacitance value of the wireless coupling coil, ω is the AC signal frequency, and j is the complex impedance; M 0i represents the mutual inductance between the signal excitation and signal reception coil and the i-th wireless coupling coil, i = 1, 2, …, N; According to the impedance matrix, the resonant frequency ω of the i-th wireless coupling coil is i as follows: If the resonance frequency ω of the wireless coupling coil i is not within the frequency range of the high-frequency alternating current signal, the resonance frequency ω is adjusted by adjusting the number of turns of the wireless coupling coil i .

2. The finger gesture sensing device based on wireless coupled resonance according to claim 1, wherein: The high-frequency signal generating and reflected signal measuring module (3) includes a ring coupler (301), a power amplifier (302), an up-conversion mixer (303), a down-conversion mixer (304), an analog-to-digital converter (305), a digital-to-analog converter (306), a control unit (307), a data output unit (308), a battery (309), a local oscillator (310), and a radio frequency switch (311); In the high-frequency signal generating part, the control unit (307) outputs a low-frequency signal. The low-frequency signal from the digital-to-analog converter (306) and the high-frequency signal generated by the local oscillator (310) are mixed by the up-conversion mixer (303) to generate a high-frequency alternating current signal; the high-frequency alternating current signal is amplified by the first power amplifier (302), and then output to the signal excitation and signal receiving coil (2) through the ring coupler (301) and the radio frequency switch (311); a part of the high-frequency alternating current signal emitted by the high-frequency signal generating part through the signal excitation and signal receiving coil (2) is coupled to the wireless coupling coil (101), and a part is reflected at each wireless coupling coil; In the high-frequency reflection measuring part, the reflected signal received by the signal excitation and signal receiving coil (2) is input to the second power amplifier (302) after passing through the radio frequency switch (311) and the ring coupler (301), amplified by the second power amplifier (302), down-converted to a low-frequency signal by the down-conversion mixer (304), input to the control unit (307) through the analog-to-digital converter (305), and finally data for attitude analysis is output to the computer through the data output unit (308).

3. The finger gesture sensing device based on wireless coupled resonance according to claim 2, characterized in that: The ring coupler (301) is used for isolation between the high-frequency output signal and the high-frequency reflected signal; the battery (309) provides power for each part of the circuit.

4. A finger gesture sensing device based on wireless coupled resonance according to claim 1, wherein: Wear one or two wireless coupling coil assemblies (1) on each finger joint; the fixing band (102) is sleeved on the finger joints of the finger, and the material of the fixing band (102) is non-metallic; the wireless coupling coil (101) is fixed on the fixing band (102), and the axis is parallel or perpendicular to the finger joint.

5. A finger gesture sensing method based on wireless coupled resonance using the device according to any one of claims 1 to 4, characterized in that, It includes the following steps: 1) Wear the wireless coupling coil assembly (1) on the finger joint of the finger to be tracked. The high-frequency signal generating part outputs a high-frequency signal, and the signal is transmitted to the wireless coupling coil (101) on the tracking finger in a coupled manner through the signal excitation and signal receiving coil (2); 2) The high-frequency reflection measurement part measures the frequency and amplitude of the reflection signal received by the signal excitation and signal receiving coil (2), denoted as G(ω,A), where ω is the reflection signal frequency and A is the corresponding reflection signal amplitude; 3) Obtain the frequency and amplitude of all maximum points from the curve corresponding to the reflection signal G(ω,A), form the frequency characteristic equation y = f(ω,A), obtain the frequency characteristic closest to the current reflection signal by solving the optimization problem, and obtain the positions between the coils according to the closest frequency characteristic, so as to complete the acquisition of the finger posture.

6. A finger gesture sensing method based on wireless coupled resonance according to claim 5, characterized in that The positions between the coils include the distance and relative inclination angle between the coils. The distance between the coils is the distance between the centers of two adjacent coils, and the relative inclination angle between the coils is the included angle between the central axes of two adjacent coils.

7. A finger gesture sensing method based on wireless coupled resonance according to claim 5, characterized in that, The specific content of step 3) is: 3.1) Obtain the frequencies and amplitudes of all maximum points from the curve corresponding to the reflected signal G(ω, A), and form the frequency characteristic equation y = f(ω, A); the frequencies of the respective maximum points are the resonant frequencies ω of the respective wireless coupling coils i ; Solve the following optimization problem based on the frequency characteristic equation to obtain the closest frequency characteristic F p (ω,A): Among them, is the set of all frequency features in the mutual inductance frequency feature dictionary; 3.2) Construct a mutual inductance frequency characteristic dictionary; 3.3) In the mutual inductance frequency feature dictionary, based on the closest frequency feature F p (ω,A), obtain the position relationship S of each wireless coupling coil under the current reflected signal p (d1,…,d N ,θ1,…,θ N ), where d i ,θ i are respectively the distance and relative tilt angle between the i-th and the (i - 1)-th coils, i = 1,…,N; Since the position of each coil on the finger is fixed after wearing, the finger posture can be obtained according to the positions S of the respective wireless coupling coils p (d1,…,d N ,θ1,…,θ N ).

8. A finger gesture sensing method based on wireless coupled resonance according to claim 7, characterized in that The specific content of step 3.2) is: According to the accuracy requirements of finger posture recognition, define P different finger postures from curled to fully extended. The positional relationship of each wireless coupling coil corresponding to each finger posture is recorded as: S p (d1,…,d N ,θ1,…,θ N ), p = 1, 2, …, P; After wearing the sensing device, perform system calibration, measure the reflection signals in P postures, extract the frequencies and amplitudes of the maximum points, and form a set of frequency characteristic equations F(ω,A) corresponding to all postures. According to the finger postures and the corresponding frequency characteristics, obtain the mutual inductance frequency characteristic dictionary, specifically:

9. A finger gesture sensing method based on wireless coupled resonance according to claim 6, characterized in that, When tracking multiple fingers, the wireless coupling coil assemblies (1) need to be worn on all the fingers to be tracked, and the signal excitation and signal receiving coils (2) corresponding to each tracked finger are installed on the back of the hand; Each signal excitation and signal receiving coil (2) is connected to the ring coupler (301) through the radio frequency switch (311); the radio frequency switch (311) switches between each signal excitation and signal receiving coil (2), and only one signal excitation and signal receiving coil (2) is turned on at the same time; after identifying the instantaneous posture of each finger, combine the postures of all the tracked fingers to complete gesture recognition.

Images