Single-interface tactile sensor with intrinsic perception and recognition and preparation method of single-interface tactile sensor

Abstract

The invention relates to a single-interface tactile sensor with intrinsic perception and recognition and a preparation method thereof, and belongs to the field of human-computer interaction, and the tactile sensor is used for recognizing a touch position and can be widely applied to the field of human-computer interaction as a human-computer interface. The touch sensor is inspired by a baseline offset process in neuron oscillation activity, an alternating current signal generated by coupling of a human body and a power frequency electric field is used as a signal source, peak and valley of the alternating current signal are subjected to differential modulation, and the amplitude of the peak and the amplitude of the valley of an electric output signal are compared, so that the touch effect is improved. Intrinsic perception and decision-making of a touch position are achieved only through one interface, data transmission is reduced, function simplification is achieved, and external power supply is not needed. The sensor can achieve self-driving and has the advantages of being high in response speed, easy to prepare, small in number of interfaces and the like.

Description

Technical Field

[0001] The present invention belongs to the field of human-computer interaction, and particularly relates to a single-interface tactile sensor with intrinsic perception and recognition and a preparation method thereof. Background Art

[0002] Tactile sensors can naturally quantify touch actions into signals recognizable by machines, which provides a key basis for perceiving touch interaction intentions and is of great significance in intelligent control, motion monitoring, dexterous robot operation, and augmented reality / virtual reality.

[0003] To achieve the tactile perception function, researchers have conducted a large number of studies. Currently, most studies on tactile sensors focus on detecting the magnitude of force. However, in the actual application of human-computer interfaces, accurate recognition of the touch position can bring a more efficient human-computer interaction experience. Traditionally, the recognition of touch positions is mainly achieved through a tactile sensor array composed of sensing units with an M×N×2 electrode array, where M and N represent longitude lines and latitude lines respectively. Although only a few sensing units receive stimuli during a single touch control operation, all sensing units transmit characteristic signals to the processing module, most of which are unnecessary redundant data, which exposes the unnecessary processing burden brought by the separation of feature perception and parsing. In addition, the discrete arrangement of sensing units imposes limitations on the continuity of touch functions, which may result in the lack of key feature information, making it impossible for machines to accurately recognize touch control operations and their basic intentions.

[0004] In summary, in the field of tactile sensors, there is an urgent need to develop a tactile sensor with a simple structure, a single interface, no external power supply, capable of autonomously generating sensing signals and realizing intrinsic perception and decision-making functions, so as to avoid the problems of complex structure and numerous interfaces, easy signal crosstalk, and cumbersome data post-processing of current tactile sensors. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a single-interface tactile sensor with intrinsic perception and recognition inspired by neuron oscillation activities and a preparation method thereof. The sensor can achieve self-driving, has the advantages of fast response speed, easy preparation, and few port numbers, and does not require an external power supply, and has the advantages of simple structure, strong anti-interference ability, and fast response.

[0006] To achieve the above object, the present invention discloses the following technical solutions:

[0007] Specifically, the present invention provides a single-interface tactile sensor with intrinsic perception and recognition, which includes a substrate layer, a conductive layer, a covering layer, and an element layer. Five touch points TP are sequentially arranged on the substrate layer i, where \(i = 1, 2, 3, 4, 5\). A diode D1 is connected to the front end of the first touch point TP1, and a diode D2 is connected to the rear end of the fifth touch point TP5. A resistor R is provided between every two adjacent touch points TP i and TP i+1 . The rear end of the diode D2 is connected to a resistor R i ; S ;

[0008] The output end of the tactile sensor is connected to a signal acquisition device, coupling the power frequency electric field, the human body, the tactile sensor and the signal acquisition device into an equivalent circuit. When the sensor is not touched, the switch S1 in the equivalent circuit is in the off state. When the sensor is touched, the signal generated by the human body coupling the power frequency electric field is transmitted into the tactile sensor, and the tactile sensor generates and outputs a voltage response signal to the signal acquisition device. The signal acquisition device analyzes the voltage response signal to determine the position of the touch point;

[0009] When the \(i\)th touch point TP i is touched, the displacement current is input from the fingertip into the \(i\)th touch point TP i to form a conductive path; then it is divided into a first path signal flowing in the direction of the diode D1 and a second path signal flowing in the direction of the diode D2. The two path signals have the same phase, the same frequency and different amplitudes, and after being superimposed and combined in the resistor R S , an approximately sinusoidal but asymmetric voltage response signal is obtained;

[0010] The amplitude ratios of the two path signals of different touch points are different. By measuring the amplitudes of the peaks and valleys in the voltage response signal, the position of the mechanical stimulus can be obtained. The expression is as follows:

[0011]

[0012] where R total is the total resistance of R1, R2, R3 and R4 in series, R L is the total resistance from the touch point \(i\) to the diode D1, and V sensor is the incoming voltage of the tactile sensor.

[0013] Preferably, each touch point has its own circuit structure to generate different voltage response signals. When \(i = 1\), the first path signal directly passes through the diode D1 to retain the positive half-wave signal. When \(i\neq1\), the first path signal passes through a total of \(i - 1\) series resistors from R i-1 to R1 for amplitude modulation and then passes through the diode D1 to retain the positive half-wave signal. When \(i = 5\), the second path signal directly passes through the diode D2 to retain the negative half-wave signal. When \(i\neq5\), the second path signal passes through R iThe amplitudes of the 5 - i series resistors from R1 to R4 are modulated and the negative half - wave signals are retained by diode D2; the first - path signal and the second - path signal have the same phase, the same frequency and different amplitudes. The two signals are superimposed and combined to obtain an approximately sinusoidal but asymmetric voltage response signal in the upper and lower directions; S After superposition and combination, an approximately sinusoidal but asymmetric voltage response signal in the upper and lower directions is obtained;

[0014] The voltage output signals of the first - path signal and the second - path signal are respectively:

[0015]

[0016] Among them, V2 and V1 are the voltage output signals of the first - path signal and the second - path signal respectively, R total is the total resistance of the series connection of R1, R2, R3 and R4, R L is the total resistance from the touch point i to diode D1, V sensor is the incoming voltage of the tactile sensor.

[0017] Preferably, the voltage input to the tactile sensor is calculated by the following formula:

[0018]

[0019] Among them, C p is the coupling capacitance between the power line and the human body in the power - frequency electric field, C b is the coupling capacitance between the human body and the ground, C iso is the coupling capacitance between the floating end of the signal acquisition device and the ground, R sensor is the equivalent total resistance of the tactile sensor, R iso is the equivalent isolation resistance of the signal acquisition device, f is the frequency of the coupled AC power supply, V a is the grid voltage.

[0020] Preferably, diode D1 is forward - conducting and diode D2 is reverse - conducting.

[0021] Preferably, the element layer is arranged below the substrate layer. The conductive layer includes a first - side conductive layer and a second - side conductive layer, and both the first - side conductive layer and the second - side conductive layer are coated with a covering layer; the substrate layer is composed of a PI film, the first - side conductive layer and the second - side conductive layer are both composed of the copper layer of the substrate layer, and the covering layer is an insulating layer.

[0022] Preferably, the power - frequency electric field is the electric field generated by electrical facilities in the surrounding environment.

[0023] Preferably, the tactile sensor is used for UAV control. During the control process, five touch points are used as recognition targets to control the takeoff, landing and movement of the UAV. When the touch points are touched, a voltage response signal is generated. After signal recognition, the direction of the UAV is controlled. The five touch points TP1 to TP5 respectively correspond to the forward movement, backward movement, takeoff and landing, left movement and right movement of the UAV.

[0024] Another aspect of the present invention also provides a preparation method of a single-interface tactile sensor with intrinsic perception and recognition, which includes the following steps:

[0025] S1. Cut the PI film with double-sided copper plating on the surface into the required shape to obtain a PI film specimen, fix the PI film specimen with a backing plate, and process positioning holes and vias on the PI film specimen;

[0026] S2. After blowing off the impurities on the surface of the PI film specimen, clean it with a citric acid solution in an ultrasonic cleaner for a certain time to remove the oxide layer on the copper surface;

[0027] S3. Paste the photosensitive dry film on the double-sided copper layer of the PI film specimen, use a hot press to remove the air bubbles between the photosensitive dry film and the copper layer, align the printed film with the positioning holes of the PI film specimen with removed air bubbles, ensure that the two film patterns coincide with the corresponding copper layers, and irradiate both sides with ultraviolet light for a certain time to make the electrode structure of the PI film specimen photosensitive;

[0028] S4. Put the PI film specimen into deionized water with an environmentally friendly etchant, take it out when the electrode structure is observed, and rinse it with deionized water until clean;

[0029] S5. Use a laser engraving machine to open windows on the two layers of PI film without plating, and the laser engraving path is automatically generated to adapt to the patterns required on the upper and lower surfaces;

[0030] S6. After aligning the positioning holes of the three-layer PI film, press the three layers together through a hot press;

[0031] S7. Use silicone conductive silver glue to fill the vias to connect the two layers of circuits;

[0032] S8. Solder the chip components on the PI film specimen to obtain the tactile sensor.

[0033] Preferably, the citric acid in step S2 is citric acid with a mass concentration of 5%.

[0034] Preferably, the time for cleaning with the citric acid solution in the ultrasonic cleaner in step S2 is 5-10 minutes.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] (1) The bionic tactile sensor designed in the present invention uses the alternating current signal generated by the coupling of the human body and the power frequency electric field as the signal source (energy source), without an external power supply, and has the advantages of simple structure, strong anti-interference ability, and fast response.

[0037] (2) Inspired by the oscillatory activity of mimicking neurons, the present invention differentiates and modulates the peaks and valleys of the alternating current signal, mimics the baseline shift process in the oscillatory activity of neurons, and realizes the intrinsic perception and decision-making of the mechanical stimulation position by comparing the amplitudes of the peaks and valleys of the electrical output signal of the sensor, reducing data transmission and simplifying the function with only one interface. Brief Description of the Drawings

[0038] Figure 1 It is a schematic diagram of the process of biological perception and recognition of external mechanical stimuli in the embodiment of the present invention;

[0039] Figure 2 It is a schematic diagram of the structure and working principle of the bionic tactile sensor in the embodiment of the present invention;

[0040] Figure 3 It is a schematic diagram of the coupling relationship between the power frequency electric field, the human body, the bionic tactile sensor, and the signal acquisition device in the embodiment of the present invention;

[0041] Figure 4 It is an equivalent circuit of the coupling relationship between the power frequency electric field, the human body, the bionic tactile sensor, and the signal acquisition device in the embodiment of the present invention;

[0042] Figure 5 It is a circuit diagram of the bionic tactile sensor in the embodiment of the present invention;

[0043] Figure 6 It is the amplitude ratio of the voltage response when mechanical stimuli are sequentially applied to each point of the bionic tactile sensor in the embodiment of the present invention;

[0044] Figure 7 It is the amplitude ratio of the voltage response when the bionic tactile sensor is subjected to mechanical stimuli of different frequencies in the embodiment of the present invention;

[0045] Figure 8 It is a schematic diagram of alternately applying stimuli to two touch points of the bionic tactile sensor in the embodiment of the present invention;

[0046] Figure 9 It is the amplitude ratio of the voltage response when Volunteer 1 alternately applies stimuli to two touch points of the bionic tactile sensor in the embodiment of the present invention;

[0047] Figure 10 It is the amplitude ratio of the voltage response when Volunteer 2 alternately applies stimuli to two touch points of the bionic tactile sensor in the embodiment of the present invention;

[0048] Figure 11 This is the heat map of the response accuracy of each point of the bionic tactile sensor in different scenarios in the embodiment of the present invention;

[0049] Figure 12 This is the working principle diagram of controlling an electronic game through the bionic tactile sensor in the embodiment of the present invention;

[0050] Figure 13 This is the control signal generated by the bionic tactile sensor when it is mechanically stimulated and the corresponding motion state in the snake game;

[0051] Figure 14 This is the schematic diagram of the scenario of controlling a drone through the bionic tactile sensor in the embodiment of the present invention, the voltage response signal generated by each action, and the corresponding amplitude ratio of the voltage response. Detailed implementation manners

[0052] Hereinafter, exemplary embodiments, features, and aspects of the present invention will be described in detail with reference to the drawings. The same reference numerals in the drawings denote elements having the same or similar functions. Although various aspects of the embodiments are shown in the drawings, the drawings do not have to be drawn to scale unless otherwise specified.

[0053] The present invention provides a single-interface tactile sensor with inherent perception and recognition inspired by neuronal oscillatory activity, including a substrate layer, a conductive layer, a covering layer, and an element layer. The conductive layer includes a first-side conductive layer and a second-side conductive layer. Covering layers are coated on the outer sides of both the first-side conductive layer (i.e., the front conductive layer) and the second-side conductive layer (i.e., the back conductive layer). The element layer is arranged below the substrate layer, and five touch points TP i , i = 1, 2, 3, 4, 5, are sequentially arranged on the substrate layer. Each touch point has a unique circuit structure to generate different voltage response signals; a diode D1 is connected to the front end of the first touch point TP1, and a diode D2 is connected to the back end of the fifth touch point TP5; a resistor R i is arranged between adjacent two touch points TP i+1 and TP i , which are R1, R2, R3, and R4 respectively. A resistor R S is connected to the back end of the diode D2.

[0054] The output end of the tactile sensor is connected to a signal acquisition device, coupling the power frequency electric field, the human body, the tactile sensor, and the signal acquisition device into an equivalent circuit. When the sensor is not touched, the switch S1 in the equivalent circuit is in the off state. When the sensor is touched, the signal generated by the human body coupling the power frequency electric field is transmitted into the tactile sensor, and the tactile sensor generates and outputs a voltage response signal to the signal acquisition device; the signal acquisition device judges the touch point position by analyzing the voltage response signal.

[0055] The process by which the tactile sensor generates a signal with symmetric positive and negative amplitudes is as follows: When the i-th touch point (i = 1, 2, 3, 4, 5) TP i is touched, the displacement current is input from the fingertip to the first touch point TP i to form a conductive path; Subsequently, the signal is divided into a first path signal in the direction of diode D1 and a second path signal in the direction of diode D2. Among them, the first path signal, without passing through (i = 1) or after passing through R i-1 to R1 (i = 2, 3, 4, 5), a total of i - 1 series resistors for amplitude modulation, after passing through diode D1, retains the positive half-wave signal. The second path signal, without passing through (i = 5) or after passing through R i to R4 (i = 1, 2, 3, 4), a total of 5 - i series resistors for amplitude modulation, after passing through diode D2, retains the negative half-wave signal.

[0056] That is, when i = 1, the first path signal directly passes through diode D1 to retain the positive half-wave signal. When i ≠ 1, the first path signal, after passing through R i-1 to R1, a total of i - 1 series resistors for amplitude modulation, passes through diode D1 to retain the positive half-wave signal; when i = 5, the second path signal directly passes through diode D2 to retain the negative half-wave signal. When i ≠ 5, the second path signal, after passing through R i to R4, a total of 5 - i series resistors for amplitude modulation, passes through diode D2 to retain the negative half-wave signal.

[0057] The phases and frequencies of the first path signal and the second path signal are the same but the amplitudes are different. Finally, the two path signals are superimposed and combined at resistor R S to obtain an approximately sinusoidal but asymmetric voltage response signal.

[0058] The signal acquisition device determines the touch point position by analyzing the voltage response signal specifically as follows:

[0059] The first path and the second path voltage output signals are respectively:

[0060]

[0061] Among them, R total is the total resistance of R1, R2, R3, and R4 in series. R L is the total resistance from the touch point i to before diode D1 on the first path. V sensor is the incoming voltage of the tactile sensor;

[0062] Based on the above formula, the ratio of the peak and valley amplitudes of the first path signal and the second path signal is expressed as:

[0063]

[0064] The amplitude ratios of different touch points are different, and the position of mechanical stimulation can be obtained by measuring the amplitudes of the peaks and valleys in the voltage response signal. In a specific embodiment, the voltage signal is collected by a data acquisition unit, and there is a peak detection function in LabView.

[0065] Preferably, the voltage applied to the tactile sensor is calculated by the following formula:

[0066]

[0067] where C p is the coupling capacitance between the power line and the human body in the power frequency electric field, C b is the coupling capacitance between the human body and the ground, C iso is the coupling capacitance between the floating end of the signal acquisition device and the ground, R sensor is the equivalent total resistance of the tactile sensor, R iso is the equivalent isolation resistance of the signal acquisition device, f is the frequency of the coupled AC power supply, and V a is the grid voltage.

[0068] Preferably, diode D1 is forward-conducting and diode D2 is reverse-conducting.

[0069] Preferably, the substrate layer is composed of a PI film, and the first surface conductive layer and the second surface conductive layer are composed of the copper layers of the substrate layer.

[0070] Preferably, the covering layer is an insulating layer.

[0071] Another aspect of the present invention also provides a preparation method of a single-interface tactile sensor with intrinsic perception and recognition, which includes the following steps:

[0072] S1. Cut the PI film with double-sided copper plating on the surface into the required shape, fix the PI film with a backing plate, and process positioning holes and vias on the PI film.

[0073] S2. After blowing off the impurities on the surface of the PI film, clean it in an ultrasonic cleaner with a citric acid solution for 5 minutes to remove the oxide layer on the copper surface.

[0074] S3. Paste the photosensitive dry film on the two copper surfaces, use a hot press to remove the air bubbles between the photosensitive dry film and the copper layer, align the printed film with the positioning holes of the PI film with the air bubbles removed, ensure that the two film patterns coincide with the corresponding copper surfaces, and irradiate both sides with ultraviolet light for a certain period of time to make the electrode structure of the specimen photosensitive.

[0075] S4. Put the specimen into deionized water with an environmentally friendly etchant, quickly take it out when the electrode structure is observed, and rinse it clean with deionized water.

[0076] S5. Use a laser engraving machine to open windows on two layers of PI films without coatings, and automatically generate the laser engraving path to adapt to the patterns required on the upper and lower surfaces.

[0077] S6. After aligning the positioning holes of the three-layer PI films, press the three layers together through a hot press.

[0078] S7. Use silicone conductive silver glue to fill the vias to connect the two layers of circuits.

[0079] S8. Solder the surface-mounted components onto the test piece to obtain the tactile sensor.

[0080] The following further explains the specific working principle of the present invention in conjunction with the accompanying drawings and embodiments:

[0081] Figure 1 The figure shows a schematic diagram of the process of biological perception and recognition of external mechanical stimuli. First, the external mechanical stimuli are converted into receptor potentials by the mechanoreceptors in the skin; subsequently, the receptor potentials are transmitted to the cerebral cortex after passing through the peripheral nerves such as nerve fibers and the spinal cord. Finally, after being processed by the complex and huge neural network composed of hundreds of millions of neurons, the recognition and perception of the position of the external mechanical stimuli are realized. Researchers have linked human perception with neuronal activities through electroencephalograms to explore the complex relationship between neuronal oscillatory activities and brain information processing. The research results show that the continuously existing neuronal oscillatory signals in the brain exhibit a non-sinusoidal characteristic called "amplitude asymmetry" or "baseline shift" in the alpha and beta frequency bands. The key to this mechanism lies in the synchronous asymmetric fluctuations caused by the differential modulation of the wave peaks and valleys. Therefore, the bionic tactile sensor should have three basic functions: internal perception, recognition, and decision-making. To achieve the above functions, the present invention uses the alternating current signal generated by coupling the human body with the power frequency electric field as the signal source of the sensor to simulate the oscillatory activities of neurons, and realizes the internal perception, recognition, and decision-making of the position of mechanical stimuli by differentially modulating the peaks and valleys of the signals to simulate the baseline shift process in neuronal activities.

[0082] Figure 2Shown is a schematic diagram of the structure and working principle of a bionic tactile sensor. First, various electrical equipment such as power facilities, household appliances, and industrial equipment generate an electric field effect during operation, and then generate an electric field in the surrounding environment. Since the voltage sources of these devices are power frequency (50 / 60 Hz), the power frequency electric field becomes the dominant electric field form in the environment. Through the coupling effect between the power frequency electric field and the human body, a weak alternating voltage signal will be generated at the fingertips. Through finger touch, the signal flows from the fingertip skin through coupling to the sensor. The sensor consists of four parts: a substrate layer, a conductive layer, a covering layer, and an element layer. The substrate layer is made of PI material, which has good flexibility and heat resistance. The copper plated on both sides of the substrate forms two conductive layers, the front conductive layer and the back conductive layer. The conductive layer is patterned to construct a circuit structure. A covering film is covered outside the conductive layer to provide insulation and prevent the influence of the external environment. The element layer is located at the bottom of the device and is used to construct a circuit. There are five touch points, TP1 to TP5, above the device, and each touch point corresponds to a different circuit structure to generate different voltage response signals.

[0083] Figure 3 Shown is a schematic diagram of the coupling relationship between the power frequency electric field, the human body, the bionic tactile sensor, and the signal acquisition device, where C p is the coupling capacitance between the power line in the surrounding environment and the human body. C1 is the coupling capacitance between the power line and the external conductor of the data acquisition unit, which can be ignored because it is very small. C b represents the coupling capacitance between the human body and the ground, and C iso represents the coupling capacitance between the floating end of the signal acquisition device and the ground. These coupling capacitances allow weak displacement currents to pass through. When the human body touches the sensor, the current flows through the coupling capacitance C p into the human body, through the sensor to the floating end of the data acquisition unit, and then through the coupling capacitance C iso into the ground. Another path directly flows into the ground through the coupling capacitance C b .

[0084] Figure 4 Shown is the equivalent circuit of the coupling relationship between the power frequency electric field, the human body, the bionic tactile sensor, and the signal acquisition device, where R sensor is the equivalent total resistance of the sensor, R iso is the equivalent isolation resistance of the signal acquisition device, f is the frequency of the coupled AC power supply, and V a is the maximum grid voltage. When the sensor is not touched, the switch S1 in the equivalent circuit is in the off state, and the signal generated by the human body coupled electric field is not transmitted to the sensor. When the sensor is touched, the signal generated by the human body coupled electric field is transmitted into the sensor, providing a signal with symmetric positive and negative amplitudes. The voltage transmitted into the tactile sensor can be given by the following formula:

[0085]

[0086] It can be seen that in different environments, C p , C b , C iso will vary in magnitude, which causes the voltage V sensor input to the tactile sensor to change with the environment. After the alternating signal provided by human body coupling passes through the touch point on the sensor, the two branches formed on both sides of the touch point can be equivalent to several series-connected resistors and diodes. Among them, this alternating signal will split into two response signals, which pass through different modulation circuits respectively. One signal will pass through the resistor on the left side of the touch point and the forward-conducting diode, and form a positive half-wave signal after flowing through R s . The other signal passes through the resistor on the right side of the touch point and the reverse-conducting diode, and forms a negative half-wave signal after flowing through R s . The two signals are superimposed on R s to make the signal a sensing signal with positive and negative asymmetry. The generated voltage output signals are V2 and V1 respectively, and are given by the following formula:

[0087]

[0088] where R total is the total resistance of R1, R2, R3, and R4 in series, and R L is the total resistance from the touch point i to before the diode D1 on the first path. Combining equations (2) and (3), the ratio of the peak amplitude to the valley amplitude can be expressed as:

[0089]

[0090] According to equation (4), it can be seen that the ratio of the peak amplitude to the valley amplitude does not change with the environment. And since the total resistance R total of R1, R2, R3, and R4 in series on the sensor remains unchanged, the sampling resistance R s remains unchanged, and the corresponding R L at different positions changes. Therefore, the position of the mechanical stimulus can be obtained by measuring the peak and valley amplitudes in the response signal without being interfered by external factors.

[0091] Figure 5 The circuit diagram of the bionic tactile sensor is shown. The touch input of human body coupling can be approximated as a constant AC voltage signal, and the two branches formed on both sides of the touch point can be equivalent to several series-connected resistors and diodes. When the i-th touch point (i = 1, 2, 3, 4, 5) TP i is touched, the displacement current is input from the fingertip to the first touch point TP iIn it, a conductive path is formed; subsequently, it is divided into a first path signal in one direction of the diode and a second path signal in the other direction of the diode. Among them, the first path signal, after amplitude modulation without passing through (i = 1) or passing through i - 1 series resistors from R i-1 to R1 (i = 2, 3, 4, 5), retains the positive half-wave signal after passing through diode one. The second path signal, after amplitude modulation without passing through (i = 5) or passing through 5 - i series resistors from R i to R4 (i = 1, 2, 3, 4), passes through diode two and retains the negative half-wave signal. The first path signal and the second path signal have the same phase and frequency but different amplitudes. After the two path signals are superimposed and combined on the resistor, an approximately sinusoidal but asymmetric voltage response signal is obtained.

[0092] Figure 6 Shown is the amplitude ratio of the voltage response when mechanical stimuli are sequentially applied to each point of the bionic tactile sensor. In order to further study the continuous spatio-temporal response ability of the sensor, in this embodiment, cyclic mechanical stimuli with an interval of 1 s are sequentially applied from touch point TP5 to TP1 and then to TP5 for testing, and the sensor can accurately and quickly output the voltage response signals corresponding to each point.

[0093] Figure 7 Shown is the amplitude ratio of the voltage response when the bionic tactile sensor is subjected to mechanical stimuli of different frequencies. In this embodiment, dynamic mechanical stimuli with frequencies of 0.25 Hz, 0.5 Hz, 1 Hz, and 2 Hz are applied to touch point TP3 of the sensor. The results show that the sensor exhibits a continuous and stable dynamic voltage response to changes in dynamic mechanical stimuli of different frequencies and has good frequency response consistency. It is proved that it can accurately and continuously respond to almost all mechanical stimuli in daily life.

[0094] Figure 8 Shown is a schematic diagram of alternately applying stimuli to two touch points of the bionic tactile sensor; when short-term mechanical stimuli with an interval of 1 s are sequentially applied to TP1 and TP3, the equivalent charge movement is as Figure 8 shown.

[0095] Figure 9 Shown is the amplitude ratio of the voltage response when volunteer 1 alternately applies stimuli to two touch points of the bionic tactile sensor. It can be seen from Figure 9 that when short-term mechanical stimuli with an interval of 1 s are sequentially applied to touch points TP1 and TP3, the sensor can quickly and stably generate an amplitude ratio with obvious regional differentiation of peaks and valleys.

[0096] Figure 10 Shown is the amplitude ratio of the voltage response when volunteer 2 alternately applies stimuli to two touch points of the bionic tactile sensor. It can be seen from Figure 10It can be seen that under the stimulation of different volunteers, the relationship between the amplitude ratio and the stimulation position remains almost unchanged, indicating that the sensor has strong robustness.

[0097] Figure 11 The heat map of the response accuracy of each point of the bionic tactile sensor under different scenarios is shown. Thanks to the proportional modulation characteristic of the sensor, regardless of the amplitude of the original input signal being large or small, the difference in the peak-to-valley amplitude ratio of the voltage response generated at the same point under different environments is very small, making its response only related to the finger touch position and independent of the environmental electric field strength. It can be seen that each point of the sensor has good accuracy under multiple scenarios.

[0098] Figure 12 The working principle diagram of playing an electronic game with a bionic tactile sensor is shown. When a finger touches the touch point on the sensor, a voltage response signal will be generated quickly. The voltage response signal is transmitted to the signal acquisition unit through a single interface. The operational amplifier amplifies the signal so that the analog-to-digital converter (ADC) can convert it into a digital signal. Subsequently, after being processed by the microcontroller unit (MCU), the signal is transmitted to the PC through USB for signal processing and analysis, and band-pass filtering, zero-point correction, and feature extraction are performed in the PC to achieve the control of up, down, left, right, and pause in the snake game according to the instructions predefined in the application program. The sensor contains a total of 5 touch points, which are TP1, TP2, TP3, TP4, and TP5 from left to right, corresponding to the up, down, left, right, and pause of the snake in the game.

[0099] Figure 13 The control signal generated by the bionic tactile sensor when subjected to mechanical stimulation and the corresponding motion state in the snake game are shown. When there is no touch, since the sensor does not generate a circuit, the output generated is very small and it is in the standby mode. When a finger touches the effective touch point of the sensor, a corresponding voltage response signal will be generated. At different touch positions, the amplitude ratio of the voltage response peak and valley is different. The PC controls the movement of the snake in the game by identifying the amplitude ratio. When the finger leaves the touch point, the voltage response signals generated by the two touch point electrodes 1 and 2 quickly disappear and return to the original state so that new control instructions can be transmitted.

[0100] Figure 14 The schematic diagram of the scenario of controlling a drone with a bionic tactile sensor, the voltage response signal generated by each action, and the corresponding amplitude ratio of the voltage response are shown. Five touch points are used as identification targets to control the takeoff, landing, and movement of the drone. When a touch point is touched, a voltage response signal is generated. After signal recognition, the direction of the drone is controlled. The five touch points correspond to the forward, backward, takeoff / landing, left, and right of the drone from left to right.

[0101] The embodiments described above are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A single-interface tactile sensor with intrinsic perception and recognition, characterized in that: It includes a substrate layer, a conductive layer, a covering layer and an element layer. Five touch points TP are sequentially arranged on the substrate layer. i , where i = 1, 2, 3, 4, 5. A first diode D1 is connected to the front end of the first touch point TP1, and a second diode D2 is connected to the rear end of the fifth touch point TP5; between two adjacent touch points TP i and TP i+1 , a resistor R is arranged. i , and the rear end of the second diode D2 is connected to a resistor R S ; The output end of the tactile sensor is connected to a signal acquisition device, coupling the power frequency electric field, the human body, the tactile sensor and the signal acquisition device into an equivalent circuit. When the sensor is not touched, the switch S1 in the equivalent circuit is in the off state. When the sensor is touched, the signal generated by the human body coupling the power frequency electric field is transmitted into the tactile sensor, and the tactile sensor generates and outputs a voltage response signal to the signal acquisition device; The signal acquisition device analyzes the voltage response signal to judge the position of the touch point; When the i-th touch point TP i is touched, a displacement current is input from the fingertip into the i-th touch point TP i to form a conductive path; Subsequently, it is divided into a first path signal flowing in the direction of diode D1 and a second path signal flowing in the direction of diode D2. The two path signals have the same phase, the same frequency and different amplitudes and are at resistor R S After superposition and combination, an approximately sinusoidal but vertically asymmetric voltage response signal is obtained; The amplitude ratios of the two signals at different touch points are different. The position of the mechanical stimulus can be obtained by measuring the amplitudes of the peaks and valleys in the voltage response signal. The expression is as follows: Among them, R total is the total resistance of R1, R2, R3, and R4 connected in series, and R L is the total resistance from the touch point i to the diode D1, and V sensor is the incoming voltage of the tactile sensor.

2. The single-interface tactile sensor with internal perception and recognition according to claim 1, characterized in that: Each touch point has its own circuit structure to generate different voltage response signals; when i = 1, the first signal directly passes through diode D1 to retain the positive half-wave signal, and when i ≠ 1, the first signal passes through the amplitude modulation of i - 1 series resistors from R to R1 and then passes through diode D1 to retain the positive half-wave signal; when i = 5, the second signal directly passes through diode D2 to retain the negative half-wave signal, and when i ≠ 5, the second signal passes through the amplitude modulation of 5 - i series resistors from R to R4 and then passes through diode D2 to retain the negative half-wave signal; the first signal and the second signal have the same phase, the same frequency, and different amplitudes, and the two signals are superimposed and combined on resistor R to obtain an approximately sinusoidal but asymmetric voltage response signal from top to bottom; i-1 to R1 for a total of i - 1 series resistors and then passes through diode D1 to retain the positive half-wave signal; when i = 5, the second signal directly passes through diode D2 to retain the negative half-wave signal, and when i ≠ 5, the second signal passes through the amplitude modulation of 5 - i series resistors from R i to R4 and then passes through diode D2 to retain the negative half-wave signal; the first signal and the second signal have the same phase, the same frequency, and different amplitudes, and the two signals are S superimposed and combined after passing through resistor R to obtain an approximately sinusoidal but asymmetric voltage response signal from top to bottom; The voltage output signals of the first signal and the second signal are respectively: Among them, V2 and V1 are the voltage output signals of the first signal and the second signal respectively, and R total is the total resistance of the series connection of R1, R2, R3, and R4, and R L is the total resistance from the touch point i to the diode D1, and V sensor is the incoming voltage of the tactile sensor.

3. The single-interface tactile sensor with intrinsic perception and recognition according to claim 1, characterized in that: The voltage transmitted into the tactile sensor is calculated by the following formula: Among them, C p is the coupling capacitance between the power line and the human body in the power frequency electric field, C b is the coupling capacitance between the human body and the ground, C iso is the coupling capacitance between the floating end of the signal acquisition device and the ground, R sensor is the equivalent total resistance of the tactile sensor, R iso is the equivalent isolation resistance of the signal acquisition device, f is the coupling AC power supply frequency, V a is the grid voltage.

4. The single-interface tactile sensor with internal perception and recognition according to claim 1, characterized in that: Diode D1 is forward-conducting, and diode D2 is reverse-conducting.

5. The single-interface tactile sensor with internal perception and recognition according to claim 1, characterized in that: The element layer is arranged below the substrate layer. The conductive layer includes a first-side conductive layer and a second-side conductive layer, and both the first-side conductive layer and the second-side conductive layer are coated with a covering layer on the outside; the substrate layer is composed of a PI film, the first-side conductive layer and the second-side conductive layer are both composed of the copper layer of the substrate layer, and the covering layer is an insulating layer.

6. The single-interface tactile sensor with intrinsic perception and recognition according to claim 1, characterized in that: The power frequency electric field is the electric field generated by electrical facilities in the surrounding environment.

7. The single-interface tactile sensor with internal perception and recognition according to claim 1, characterized in that: The tactile sensor is used for UAV control. During the control process, five touch points are used as recognition targets to control the takeoff, landing and movement of the UAV. When the touch point is touched, a voltage response signal is generated. After signal recognition, the direction of the UAV is controlled. The five touch points TP1 to TP5 respectively correspond to the UAV moving forward, moving backward, taking off and landing, moving left and moving right.

8. A preparation method for the single-interface tactile sensor with intrinsic perception and recognition as described in claim 1, characterized in that: It includes the following steps: S1. Cut the PI film with double-sided copper plating on the surface into the required shape to obtain a PI film specimen, fix the PI film specimen with a backing plate, and process positioning holes and via holes on the PI film specimen; S2. After blowing off the impurities on the surface of the PI film specimen, clean it with a citric acid solution in an ultrasonic cleaner for a certain time to remove the oxide layer on the copper surface; S3. Paste the photosensitive dry film on the double-sided copper layer of the PI film specimen, use a hot press to remove the bubbles between the photosensitive dry film and the copper layer, align the printed film with the positioning holes of the PI film specimen with removed bubbles, ensure that the two film patterns coincide with the corresponding copper layers, and use ultraviolet light to irradiate both sides for a certain time to make the electrode structure of the PI film specimen photosensitive; S4. Put the PI film specimen into deionized water with an environmentally friendly etchant, take it out when the electrode structure is observed, and rinse it with deionized water until clean; S5. Use a laser engraving machine to open windows on the two layers of PI film without plating, and the laser engraving path is automatically generated to adapt to the patterns required on the upper and lower surfaces; S6. After aligning the positioning holes of the three-layer PI film, press the three layers together through a hot press; S7. Use silicone conductive silver glue to fill the via holes to connect the two-layer circuits; S8. Solder the chip components on the PI film specimen to obtain the tactile sensor.

9. The preparation method of the single-interface tactile sensor with internal perception and recognition according to claim 8, characterized in that: The citric acid in step S2 is citric acid with a mass concentration of 5%; 10. The preparation method of the single-interface tactile sensor with internal perception and recognition according to claim 9, characterized in that: In step S2, cleaning with the citric acid solution in the ultrasonic cleaner for a certain time is 5 - 10 minutes.

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