Tactile perception evaluation method and system based on electric tactile virtual reality

Abstract

The invention belongs to the technical field of virtual reality, and particularly discloses a tactile perception evaluation method and system based on electric tactile virtual reality, and the method comprises the following steps: S1, a user wears VR glasses and wears a microelectrode array on a finger, and the VR glasses are started to enter a virtual scene; s2, the first controller obtains the pattern of the shielded virtual pattern clicked by the user and transmits the pattern to the second controller, and the first controller generates stimulation current according to the pattern of the shielded virtual pattern to trigger the micro electrode array on the finger sending the click instruction; s3, the user feeds back the pattern shape felt by the user to the second controller, and the second controller compares the real pattern shape, the pattern shape fed back by the user and the reaction time to calculate the touch perception ability level. By adopting the technical scheme, high spatial resolution and flexible tactile stimulation are realized through the surrounding suppression structure, various tactile patterns can be accurately simulated, and a user is supported to experience abundant tactile perception tasks in a virtual environment.

Description

Technical Field

[0001] The invention belongs to the technical field of virtual reality, and relates to a tactile perception evaluation method and system based on electrotactile virtual reality. Background Art

[0002] As one of the five senses, touch is an important means of perception for humans to interact with the external environment. It not only helps us perceive the shape, texture and temperature of objects, but also plays an important role in spatial perception and exploration of the physical world. With the development of technologies such as virtual reality (VR) and augmented reality (AR), the interactive experience of the digital world has become increasingly rich. However, most of the current digital interactions rely on vision and hearing, and the lack of tactile feedback limits the user's immersion and interaction accuracy in the virtual environment.

[0003] Although significant progress has been made in virtual tactile generation, improving tactile simulation and perception capabilities remains a technical challenge that needs to be overcome.

[0004] Existing tactile feedback mostly relies on mechanical devices. Although they can simulate a certain physical touch, they are often large in size and complex in structure, making it difficult to accurately control and achieve portability. In contrast, electrotactile stimulation has become a more suitable tactile feedback method for virtual environments due to its precise control of intensity, frequency and duration. Microcurrent regulation not only allows independent stimulation of each electrode, but also reduces user interference and is highly safe, making it very suitable for virtual tactile training and long-term interactive tasks.

[0005] In addition, users with reduced tactile perception sensitivity or impaired perception due to nerve damage also urgently need effective tactile perception assessment and training methods to improve their tactile sensitivity in daily life. However, existing tactile assessment methods mostly rely on simple touch or physical tests, lack flexible and personalized dynamic training scenarios, and cannot fully meet individual needs. Therefore, designing a tactile feedback system that adapts to virtual environments, is reusable, and can provide accurate quantitative assessments has become an urgent problem to be solved. Summary of the invention

[0006] The purpose of the present invention is to provide a tactile perception evaluation method and system based on electrotactile virtual reality, which can achieve high spatial resolution and flexible tactile stimulation through a surround inhibition structure, accurately simulate a variety of tactile patterns, and support users to experience rich tactile perception tasks in a virtual environment.

[0007] In order to achieve the above object, the basic scheme of the present invention is: a tactile perception evaluation method based on electrotactile virtual reality, comprising the following steps:

[0008] S1. The user wears a VR headset and a microelectrode array on the finger, turns on the VR headset to enter the virtual scene, and uses the finger wearing the microelectrode array to click on the virtual pattern blocked in the virtual scene.

[0009] S2. The first controller obtains the pattern of the blocked virtual pattern clicked by the user and transmits it to the second controller. The first controller generates a stimulation current according to the pattern of the blocked virtual pattern to trigger the microelectrode array on the finger that issues the click command.

[0010] S3. The user feeds back the pattern shape he / she feels to the second controller. The second controller compares the real pattern shape, the pattern shape fed back by the user, and the reaction time to calculate the level of tactile perception ability.

[0011] The working principle and beneficial effects of this basic solution are as follows: In this technical solution, various tactile patterns are simulated on the electrode array through current, and the subject can perform diverse tactile perception tasks in the virtual environment. Compared with the traditional scale evaluation or the test method of touching sandpaper, this method is more convenient, can accurately quantify the tactile perception ability, reduce costs, and support diverse virtual training scenarios.

[0012] This technology has broad application potential in the fields of medical rehabilitation, VR and AR immersive experiences, etc., providing a safe and non-invasive training platform for groups with decreased tactile sensitivity. Although the system cannot directly restore the user's tactile perception ability, through a series of precise tactile perception tasks and virtual training, it can effectively improve the user's tactile sensitivity in the immersive virtual environment and achieve scientific quantitative evaluation.

[0013] Further, in steps S1 and S2, based on the virtual scene, the subject clicks on multiple virtual boxes with blocked information. The first controller obtains the click information and stimulates the tactile corpuscles at the fingertips through the electrode array to form a tactile sensation corresponding to the virtual pattern.

[0014] The subject judges the pattern shape perceived in the tactile feedback at the fingertips. The second controller records the result of his / her judgment and the reaction time to quantify the subject's tactile perception ability.

[0015] If the subject's tactile perception ability is lower than the standard deviation level, repetitive tactile training is provided to gradually improve the subject's tactile sensitivity in the immersive virtual environment.

[0016] The electrode array worn on the user's index finger simulates various tactile patterns through the microcurrent provided by the electrical stimulation generator, and the VR headset serves as a bridge for visual communication, which can improve the subject's tactile perception accuracy and reaction time.

[0017] Further, the first controller generates a stimulation current for the microelectrode array on the finger that triggers a click command according to the pattern of the occluded virtual pattern. The method is as follows:

[0018] S31. Obtain the pattern shape, and divide the pattern into a key stimulation area, a general stimulation area, and a non-stimulation area;

[0019] S32. The first controller issues a control command to simultaneously stimulate the electrodes corresponding to the key stimulation area and the general stimulation area and lasts for a first period of time. The user feeds back the pattern shape they feel to the second controller;

[0020] S33. The first controller issues a control command to only stimulate the key stimulation area and lasts for a second period of time. The user feeds back the pattern shape they feel to the second controller;

[0021] S34. The first controller issues a stimulation signal of a first intensity to the electrodes in the key stimulation area, and issues a stimulation signal of a second intensity to the electrodes corresponding to the general stimulation area and lasts for a third period of time. The first intensity is stronger than the second intensity. The user feeds back the pattern shape they feel to the second controller;

[0022] S35. The second controller generates a final feedback based on the three times of feedback.

[0023] The first controller generates a stimulation current for the microelectrode array on the finger that triggers a click command according to the pattern of the occluded virtual pattern, which is beneficial for use.

[0024] Further, the method for the second controller to calculate the tactile perception ability by comparing the real pattern shape, the pattern shape fed back by the user, and the reaction time is as follows:

[0025] S41. Obtain the pattern fed back by the user and the real pattern;

[0026] S42. Adjust the pattern fed back by the user and the real pattern to the same size and make them correspond;

[0027] S43. Using the points of the real pattern as a template, the points in the pattern fed back by the user are made to correspond. If there is no corresponding point in the pattern fed back by the user, add the point in the pattern fed back by the user and set the coordinate value of the point to 0; if there is a point in the pattern fed back by the user but no corresponding point in the real pattern, delete the point in the pattern fed back by the user;

[0028] S42. Calculate the feedback error E of the pattern shape, where N is the total number of points of the real pattern:

[0029]

[0030] Where N is the total number of points of the real pattern, k is the total number of points deleted in the pattern feedback by the user, i is the serial number of the point of the real pattern, and S u (ix) is the x - coordinate of the i - th point of the pattern perceived by the user, and S r (ix) is the x - coordinate of the i - th point of the real pattern, and S u (iy) is the y - coordinate of the i - th point of the pattern perceived by the user, and S r (iy) is the y - coordinate of the i - th point of the real pattern, and d is the distance between the deleted point and the center point; the tactile perception ability C is:

[0031]

[0032] Where α is an adjustment factor which can be set, T is the reaction time, and E 0 is the diameter size of the real pattern, and T 0 is the standard reaction time.

[0033] The second controller compares the shape of the real pattern, the shape of the pattern feedback by the user, and the reaction time, calculates the tactile perception ability, and provides a convenient and specific tactile quantitative evaluation for the user.

[0034] Furthermore, it also has the following steps:

[0035] Adopt the Euclidean distance method to evaluate the difficulty of different tactile patterns. The specific method is as follows:

[0036] Standardize the recognition accuracy and reaction time data of the subjects for the tactile patterns, and scale them into the interval of [-1, 1];

[0037] Take the overall average accuracy and reaction time of each pattern as the coordinate axes. Set the abscissa interval as [2, -2], the ordinate interval as [-2, 2], and the origin as (2, -2). The closer the coordinate point is to the origin, the higher the recognition accuracy of the pattern and the shorter the reaction time, indicating that the pattern is easy to be perceived and recognized;

[0038] Calculate the Euclidean distance of each pattern, and take the group with the best performance in accuracy and reaction time as the reference pattern, and define its difficulty level as 1 point;

[0039] According to the relative Euclidean distance ratio of other patterns to the reference pattern, calculate the difficulty score of each pattern. The specific scores are as follows:

[0040] 'Group 1': 1.5, 'Group 2': 1.0, 'Group 3': 2.75, 'Group 4': 3.06, 'Group 5': 4.28;

[0041] The scores are sorted from easy to difficult according to the recognition difficulty of the patterns, providing a quantitative evaluation framework for tactile perception ability based on the level of difficulty.

[0042] Provide a quantitative evaluation framework for tactile perception ability based on the level of difficulty, providing a better basis for tactile quantitative evaluation.

[0043] The present invention also provides an electro - stimulation tactile perception evaluation interaction system based on the method of the present invention, including a micro - electrode array, an electro - stimulation generator, a VR glasses, and a processing unit embedded with evaluation rules;

[0044] The micro - electrode array is worn on the fingertips of the user. In the feedback tactile area, that is, in the fingertips, the electrode array serves as the anode, and the electrode array on the back of the finger serves as the common cathode;

[0045] The electro - stimulation generator generates pulsed current for the path connected to each electrode of the micro - electrode array, where the stimulating electrode is connected to the positive current and the inhibitory electrode is connected to the negative current;

[0046] The VR glasses are worn on the eyes of the user;

[0047] The processing unit is respectively connected to the micro - electrode array, the electro - stimulation generator, and the VR glasses. The processing unit includes a first controller and a second controller. The first controller acquires the pattern of the occluded virtual pattern clicked by the user and transmits it to the second controller. The first controller generates a stimulating current according to the pattern of the occluded virtual pattern to trigger the micro - electrode array on the finger that issues the click command. The user feeds back the pattern shape they feel to the second controller. The second controller compares the real pattern shape, the pattern shape fed back by the user, and the reaction time to calculate the level of tactile perception ability.

[0048] This system combines the micro - electrode array, the electro - stimulation generator, the tactile evaluation rules, and the virtual scene to construct a safe, non - invasive, and reusable tactile perception evaluation interaction system, providing convenient and specific tactile quantitative evaluation and personalized training for users.

[0049] Further, the micro - electrode array includes a central electrode and a surrounding electrode. The central electrode is a stimulating electrode, and the surrounding electrode is an inhibitory electrode. The inhibitory electrode applies a unidirectional wave opposite to that of the stimulating electrode, and the current amplitude is less than that of the stimulating electrode.

[0050] On the one hand, this restricts the diffusion of the stimulating current and reduces interference; on the other hand, it cancels the charge accumulation and delays the generation of numbness.

[0051] Further, the current ratio of the inhibitory electrode to the stimulating electrode is 1:4.

[0052] When the magnitude of the suppression current is 1 / 4 of the magnitude of the stimulation current, the current density in the central electrode region is the most concentrated, optimizing the ratio of the magnitudes of the suppression current and the stimulation current.

[0053] Furthermore, the microelectrode array adopts a 12-point electrode array layout of 3×4, and the electrodes are square electrodes.

[0054] Square electrodes perform better in terms of current concentration. Based on the research on the size of the tactile sensitive area of the normal population (about 1 - 1.5 cm 2 ), and the two-point tactile threshold (2 - 4 mm), a 12-point electrode array layout of 3×4 is selected, and the tactile perception effect is better.

[0055] Furthermore, the microelectrode array is arranged on a fabric substrate, and the fabric substrate is obtained by compounding a TPU insulating film and a nylon substrate.

[0056] The fabric substrate is used for the insulation protection and encapsulation of the electrode region, has a soft texture, and high use comfort. Description of the Drawings

[0057] Figure 1 is a schematic flowchart of the tactile perception evaluation method based on electro-tactile virtual reality of the present invention;

[0058] Figure 2 is a schematic diagram of the simulated change of the stimulation current of the electro-stimulation tactile perception evaluation interaction system of the present invention;

[0059] Figure 3 is a schematic diagram of the standard deviation distribution of the tactile cognitive ability scores of the subjects of the tactile perception evaluation method based on electro-tactile virtual reality of the present invention. Detailed Embodiments

[0060] The following details the embodiments of the present invention. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0061] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0062] In the description of the present invention, unless otherwise specified and defined, it should be noted that the terms "installation", "connection", and "linkage" should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection, or it can be the communication inside two components. It can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0063] The present invention discloses a tactile perception evaluation method based on electro-tactile virtual reality. As Figure 1 shown, it includes the following steps:

[0064] S1, the user wears a VR glasses and wears a microelectrode array on the finger, turns on the VR glasses (the virtual finger generated by the Ultra leap 3D i technology in the VR glasses will touch the pattern on the screen) to enter the virtual scene, and clicks the virtual pattern blocked in the virtual scene with the finger wearing the microelectrode array;

[0065] S2, the first controller obtains the pattern of the blocked virtual pattern clicked by the user and transmits it to the second controller. The first controller generates a stimulation current according to the pattern of the blocked virtual pattern (select a suitable microcurrent gear, such as 1 mA, 2 mA or 4 mA) to trigger the microelectrode array on the finger that issues the click command;

[0066] S3, the user feeds back the pattern shape he feels to the second controller (specifically, the user can draw or click the corresponding image selection button to determine the pattern shape he feels and transmit it to the second controller). The second controller compares the real pattern shape, the pattern shape fed back by the user, and the reaction time, and calculates the level of tactile perception ability.

[0067] In a preferred embodiment of the present invention, in steps S1 and S2, based on the virtual scene, the subject clicks on multiple virtual boxes with blocked information (which can be marked as "+"). The first controller obtains the click information and stimulates the tactile corpuscles at the fingertips through the electrode array to form a tactile sensation corresponding to the virtual pattern;

[0068] The subject judges the pattern shape perceived in the tactile feedback at the fingertips. The second controller records the result of his judgment and the reaction time, and quantifies the tactile perception ability of the subject;

[0069] If the tactile perception ability of the subject is lower than the standard deviation level, repetitive tactile training is provided. The repetitive electrostimulation pattern simulation training can effectively improve the tactile perception ability score and gradually improve the tactile sensitivity of the subject in the immersive virtual environment.

[0070] In a preferred embodiment of the present invention, the first controller generates a stimulating current to trigger a corresponding microelectrode array on the finger that issues a click command according to the pattern of the occluded virtual pattern. The method is as follows:

[0071] S31. Obtain the pattern shape, and divide the pattern into a key stimulation area, a general stimulation area, and a non-stimulation area. The pattern shape includes simple lines (such as horizontal line segments, vertical line segments, left-inclined line segments, right-inclined line segments), geometric figures (such as "cross" shapes, "X" shapes, squares, rectangles), and complex figures (such as smiling faces, sad faces, etc.). Simple line figures mainly test the perception of direction and length, geometric figures introduce elements of shape and spatial relationship, and complex figures involve multiple visual features such as points, lines, angles, and symmetry. Specifically, the area outside the pattern can be set as the non-stimulation area, the boundary points of the pattern and the intersection points of the lines in the pattern are the key stimulation areas, and the others are the general stimulation areas.

[0072] S32. The first controller issues a control command to simultaneously stimulate the electrodes corresponding to the key stimulation area and the general stimulation area and lasts for a first period of time. The user feeds back the pattern shape they feel to the second controller.

[0073] S33. The first controller issues a control command to only stimulate the key stimulation area and lasts for a second period of time. The user feeds back the pattern shape they feel to the second controller.

[0074] S34. The first controller issues a stimulation signal of a first intensity to the electrodes in the key stimulation area, and issues a stimulation signal of a second intensity to the electrodes corresponding to the general stimulation area and lasts for a third period of time. The first intensity is stronger than the second intensity. The user feeds back the pattern shape they feel to the second controller. The first period of time, the second period of time, and the third period of time can be the same or different, and are determined according to the actual click event of the user.

[0075] S35. The second controller generates a final feedback based on the three feedbacks. Specifically, the pattern with the most feedback among the three feedbacks is the final feedback. If the number of feedbacks is the same, the pattern of the last feedback is the final feedback. By distinguishing the key stimulation area, the general stimulation area, and the non-stimulation area, the stimulation feeling of the key area can be highlighted, and the correctness of the user's feeling can be improved.

[0076] In a preferred embodiment of the present invention, the method for the second controller to calculate the tactile perception ability by comparing the real pattern shape, the pattern shape fed back by the user, and the reaction time is as follows:

[0077] S41. Obtain the pattern fed back by the user and the real pattern.

[0078] S42. Adjust the pattern feedback by the user and the real pattern to the same size and make corresponding adjustments. For example, the size of the outer boundary can be adjusted to be the same. For example, the maximum values of the horizontal and vertical dimensions of the pattern are adjusted to be the same, and the key areas are made corresponding;

[0079] S43. Use the points of the real pattern as a template and make corresponding points in the pattern feedback by the user. If there is no corresponding point in the pattern feedback by the user, add the point in the pattern feedback by the user and set the coordinate value of the point to 0; if there is a point in the pattern feedback by the user but no corresponding point in the real pattern, delete the point in the pattern feedback by the user;

[0080] S42. Calculate the feedback error E of the pattern shape:

[0081]

[0082] where N is the total number of points of the real pattern, k is the total number of points deleted in the pattern feedback by the user, i is the serial number of the point of the real pattern, S u (ix) is the x coordinate of the i-th point of the pattern perceived by the user, S r (ix) is the x coordinate of the i-th point of the real pattern, S u (iy) is the y coordinate of the i-th point of the pattern perceived by the user, S r (iy) is the y coordinate of the i-th point of the real pattern, d is the distance between the deleted point and the center point; the tactile perception ability C is:

[0083]

[0084] where α is an adjustment factor that can be set, T is the reaction time, E 0 is the diameter size of the real pattern (the maximum distance from one edge of the real pattern to the opposite edge point, or the diameter of the circumscribed circle of the pattern), T 0 is the standard reaction time.

[0085] In a preferred embodiment of the present invention, the following steps are further included:

[0086] Use the Euclidean distance method to evaluate the difficulty levels of different tactile patterns. The specific method is as follows:

[0087] Standardize the recognition accuracy and reaction time data of the subjects for the tactile patterns and scale them to the interval [-1, 1];

[0088] Taking the overall average accuracy and reaction time of each pattern as the coordinate axes, set the abscissa interval as [2, -2], the ordinate interval as [-2, 2], and the origin as (2, -2). The closer the coordinate point is to the origin, the higher the recognition accuracy of the pattern and the shorter the reaction time, indicating that the pattern is easy to be perceived and recognized;

[0089] Calculate the Euclidean distance of each pattern, and take the group with the best performance in accuracy and reaction time as the reference pattern, and define its difficulty level as 1 point;

[0090] According to the relative Euclidean distance ratio between other patterns and the reference pattern, calculate the difficulty scores of each pattern. The specific scores are:

[0091] 'Group 1': 1.5, 'Group 2': 1.0, 'Group 3': 2.75, 'Group 4': 3.06, 'Group 5': 4.28;

[0092] The scores are sorted from easy to difficult according to the recognition difficulty of the patterns, providing a quantitative evaluation framework for tactile perception ability based on difficulty level.

[0093] The evaluation of tactile perception ability not only depends on the recognition accuracy of the patterns, but also involves the reaction time of the subjects and the difficulty level of the patterns. In order to quantify the tactile perception ability of the subjects and consider the difficulty level of the patterns, the Euclidean distance is used to evaluate the difficulty level of each pattern group, and the tactile perception ability scores of 30 subjects can be calculated (as Figure 3 shown, the X-axis represents the score range, and the Y-axis shows the number of subjects in this score range), including the average value and the standard deviation.

[0094] The present invention also provides an electrostimulation tactile perception evaluation interaction system (TPE IS) based on the method described in the present invention, including a microelectrode array, an electrostimulation generator, a VR glasses, and a processing unit embedded with evaluation rules.

[0095] The microelectrode array is worn on the fingertips of the user. In the feedback tactile area, that is, in the fingertips, the electrode array serves as the anode, and the electrode array on the back of the finger serves as the common cathode.

[0096] The electrostimulation generator generates pulsed current for the path connected to each electrode of the microelectrode array, where the stimulating electrode (hydrogel patch electrode) is connected to the positive current, and the inhibitory electrode is electrically connected to the negative current. The VR glasses are worn on the eyes of the user. This design enables the current to flow through the nerves on the skin side of the fingertips, achieving effective tactile feedback. And because the density of mechanoreceptors on the back of the finger is much lower than that on the finger abdomen, the electrode on the back of the finger will not cause tactile stimulation, thus avoiding interference.

[0097] The processing unit is respectively connected to the microelectrode array, the electrical stimulation generator, and the VR glasses. The processing unit includes a first controller and a second controller. The first controller acquires the pattern of the occluded virtual pattern clicked by the user and transmits it to the second controller. The first controller generates a stimulation current according to the pattern of the occluded virtual pattern to trigger the microelectrode array on the finger that issues the click command. The user feeds back the pattern shape they feel to the second controller. The second controller compares the real pattern shape, the pattern shape fed back by the user, and the reaction time to calculate the level of tactile perception ability.

[0098] In a preferred embodiment of the present invention, the accurate resolution of tactile perception ability is interfered by the current diffusion characteristics. Current diffusion will affect the accuracy of tactile perception and may cause a certain degree of numbness.

[0099] To solve this problem, the microelectrode array includes a central electrode and a surrounding electrode. The central electrode is a stimulation electrode, and the surrounding electrode is an inhibitory electrode. The inhibitory electrode applies a unidirectional wave opposite to that of the stimulation electrode, and the current amplitude is smaller than that of the stimulation electrode. On the one hand, this restricts the diffusion of the stimulation current and reduces interference; on the other hand, it cancels the charge accumulation and delays the generation of numbness.

[0100] In the case of having inhibitory electrodes, the accuracy of the vast majority of subjects in recognizing simple line graphics is significantly higher than that in the case of having no inhibitory electrodes.

[0101] In a preferred embodiment of the present invention, to optimize the amplitude ratio of the inhibitory current to the stimulation current, the change of the inhibitory: stimulation current ratio from 0 to 1 is analyzed by COMSOL simulation, as Figure 2 shown. When the amplitude of the inhibitory current is 1 / 4 of the stimulation current, the current density in the central electrode region is the most concentrated. Therefore, the optimal ratio is determined: the current ratio of the inhibitory electrode to the stimulation electrode is 1:4. Preferably, the pulse frequency set by the system is 500 Hz, the pulse width is 200 μs, and the amplitude of the stimulation current is 2 mA. These current parameters can provide a comfortable tactile perception experience for most users.

[0102] In a preferred embodiment of the present invention, based on the research on the size of the tactile sensitive area (about 1 - 1.5 cm 2 ) and the two-point tactile threshold (2 - 4 mm) of the normal population, the microelectrode array adopts a 12-point electrode array layout of 3×4, and the electrodes are square electrodes. Since the fabric substrate cannot support back wiring, a notch needs to be opened in the inhibitory electrode for the introduction of the stimulation current. By simulating and comparing the designs with and without notches, this adjustment does not affect the current density distribution.

[0103] In a preferred embodiment of the present invention, the microelectrode array is disposed on a fabric substrate, which is obtained by laminating a TPU insulating film and a nylon substrate. The microelectrode array uses a platinum-carbon metal electrode (such as Guangdong Ark Manufacturing Technology Co., Ltd., model FZ-BT9505), which consists of nano pure carbon powder, carbon nanotubes and platinum powder. Among them, the nano pure carbon powder provides basic conductivity, the carbon nanotubes enhance the mechanical strength and flexibility of the electrode, and the platinum powder improves its chemical stability and corrosion resistance. The platinum-carbon metal electrode provides excellent conductivity and wear resistance; the TPU insulating film has the characteristics of low cost and high durability, and is used for insulating protection and encapsulation of the electrode area.

[0104] The wire material connecting the electrodes uses silver paste (Ark brand, model FZ-DJ086), which contains flaky silver powder, spherical silver powder and silver chloride powder. The flaky silver powder improves conductivity, the spherical silver powder improves fluidity and printing uniformity, and the silver chloride powder enhances material stability. Polyvinylpyrrolidone (PVP) is added as a binder to both metal materials, and polyvinyl alcohol (PVA) is added to improve mechanical strength. At the same time, epoxy resin is used to enhance wear resistance and durability. To ensure the uniform distribution of the silver paste, DBE solvent is used to adjust its fluidity. The mixed material is subjected to high-speed stirring treatment to ensure good conductivity and uniformity of the carbon-platinum and silver paste.

[0105] Preferably, the fabric substrate is preferably made of nylon cloth, which has good softness and comfort. It ensures that the device provides efficient tactile feedback without affecting the user's finger movement, and is suitable for long-term wear. Nylon is selected as the fabric substrate, and the TPU insulating film is laminated with the nylon substrate through a high-temperature thermal lamination process to obtain a composite substrate with flexibility and wear resistance. After designing the electrode array pattern, the carbon-platinum and silver paste are deposited on the composite substrate through a screen printing process.

[0106] After printing, the substrate needs to be baked twice: high-temperature curing is carried out at 150 °C to remove the solvent. Finally, a layer of TPU insulating film is coated around the electrode layer to ensure the electrical insulation of the non-electrode area and the safety of the device.

[0107] This makes the microelectrode array ultra-thin, flexible and wearable. The electrode array worn by the user on the index finger provides microcurrents through an electrical stimulator to simulate various tactile patterns, and the VR glasses serve as a bridge for visual communication.

[0108] This system uses a microelectrode array on a fabric substrate to achieve high spatial resolution and flexible tactile stimulation through a surround suppression structure, which can accurately simulate various tactile patterns and support users to experience rich tactile perception tasks in a virtual environment.

[0109] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples.

[0110] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A tactile perception evaluation method based on electrotactile virtual reality, characterized in that: The steps include: S1, the user wears VR glasses and wears micro-electrode arrays on his fingers, turns on the VR glasses to enter the virtual scene, and clicks on the blocked virtual pattern in the virtual scene with the finger wearing the micro-electrode array; S2, the first controller obtains the pattern of the blocked virtual pattern clicked by the user and transmits it to the second controller, and the first controller generates a stimulation current according to the pattern of the blocked virtual pattern to trigger the micro-electrode array on the finger that issues the click command; S3, the user feeds back the pattern shape he feels to the second controller, and the second controller compares the real pattern shape, the pattern shape fed back by the user, and the reaction time to calculate the tactile perception ability level.

2. The tactile perception evaluation method based on electrotactile virtual reality according to claim 1, characterized in that: In steps S1 and S2, based on the virtual scene, the subject clicks on a plurality of virtual boxes whose information is blocked, and the first controller obtains the click information and stimulates the tactile bodies of the fingertips through the electrode array to form a tactile sensation corresponding to the virtual pattern; The subject judges the shape of the pattern perceived in the fingertip tactile feedback, and the second controller records the result of its judgment and reaction time to quantify the subject's tactile perception ability; If the subject's tactile perception ability is below the standard deviation level, provide repetitive tactile training to gradually improve the subject's tactile sensitivity in the immersive virtual environment.

3. The tactile perception evaluation method based on electrotactile virtual reality according to claim 2, characterized in that: The first controller generates a stimulation current according to the pattern of the blocked virtual pattern to trigger the micro-electrode array on the finger that issues the click command, and the method is: S31, obtaining the pattern shape, and dividing the pattern into a key stimulation area, a general stimulation area, and a non-stimulation area; S32, the first controller issues a control command to simultaneously stimulate the electrodes corresponding to the key stimulation area and the general stimulation area for a first time, and the user feeds back the pattern shape he feels to the second controller; S33, the first controller issues a control command to stimulate only the key stimulation area for a second time, and the user feeds back the pattern shape he feels to the second controller; S34, the first controller sends a stimulation signal of a first intensity to the electrodes in the key stimulation area, and sends a stimulation signal of a second intensity to the electrodes corresponding to the general stimulation area for a third time, wherein the first intensity is stronger than the second intensity, and the user feeds back the pattern shape he / she feels to the second controller; S35: The second controller generates final feedback according to the three feedbacks.

4. The tactile perception evaluation method based on electrotactile virtual reality according to claim 2, characterized in that: The second controller compares the real pattern shape, the pattern shape fed back by the user, and the reaction time, and calculates the tactile perception ability in the following manner: S41, obtaining a pattern fed back by a user and a real pattern; S42, adjusting the pattern fed back by the user and the real pattern to the same size and making them correspond; S43, using the points of the real pattern as templates, the points in the pattern fed back by the user are matched, if there is no corresponding point in the pattern fed back by the user, then the point is added to the pattern fed back by the user and the coordinate value of the point is set to 0; if there is a point in the pattern fed back by the user but there is no corresponding point in the real pattern, then the point is deleted from the pattern fed back by the user; S42, calculate the feedback error E of the pattern shape, where N is the total number of points of the real pattern: Where N is the total number of points in the real pattern, k is the total number of points deleted from the pattern reported by the user, i is the serial number of the point in the real pattern, S u (ix) is the x-coordinate of the i-th point of the pattern perceived by the user, S r (ix) is the x-coordinate of the ith point of the real pattern, S u (iy) is the ordinate of the i-th point of the user’s perceived pattern, S r (iy) is the ordinate of the i-th point of the real pattern, d is the distance between the deleted point and the center point; the tactile perception ability C is: Among them, α is the adjustment factor, which can be set; T is the reaction time, E0 is the diameter of the real pattern, and T0 is the standard reaction time.

5. The tactile perception evaluation method based on electrotactile virtual reality according to claim 2, characterized in that: It also has the following steps: The Euclidean distance method is used to evaluate the difficulty of different tactile patterns. The specific method is as follows: The subjects’ recognition accuracy and reaction time data of tactile patterns were standardized and scaled to the interval of [-1,1]; The overall average accuracy and reaction time of each pattern are used as coordinate axes, and the horizontal axis interval is set to [2,-2], the vertical axis interval is set to [-2,2], and the origin is set to (2,-2). The closer the coordinate point is to the origin, the higher the recognition accuracy of the pattern and the shorter the reaction time, indicating that the pattern is easy to be perceived and recognized; The Euclidean distance of each pattern was calculated, and the group with the best accuracy and reaction time performance was used as the benchmark pattern, and its difficulty was defined as 1 point; The difficulty score of each pattern is calculated based on the relative Euclidean distance ratio between other patterns and the benchmark pattern. The specific scores are: 'Group 1':1.5,'Group 2':1.0,'Group 3':2.75,'Group 4':3.06,'Group 5':4.28; The scores are ranked from easy to difficult according to the difficulty of pattern recognition, providing a quantitative, difficulty-based assessment framework for tactile perception ability.

6. An electrical stimulation tactile perception evaluation interactive system based on the method according to any one of claims 1 to 5, characterized in that: It includes a microelectrode array, an electrical stimulation generator, VR glasses, and a processing unit with embedded evaluation rules; The microelectrode array is worn on the fingertips of the user, and in the tactile feedback area, i.e., the fingertips, the electrode array serves as an anode, and the electrode array on the back of the finger serves as a common cathode; The electrical stimulation generator generates a pulse current for a pathway connected to each electrode of the microelectrode array, wherein the stimulation electrode is connected to a positive current and the inhibition electrode is connected to a negative current; The VR glasses are worn on the eyes of the user; The processing unit is respectively connected to the micro-electrode array, the electrical stimulation generator, and the VR glasses. The processing unit includes a first controller and a second controller. The first controller obtains the pattern of the blocked virtual pattern clicked by the user and transmits it to the second controller. The first controller generates a stimulation current according to the pattern of the blocked virtual pattern to trigger the micro-electrode array on the finger that issues a click command. The user feeds back the shape of the pattern he feels to the second controller. The second controller compares the real pattern shape, the pattern shape fed back by the user, and the reaction time to calculate the level of tactile perception ability.

7. The electrical stimulation tactile perception evaluation interactive system according to claim 6, characterized in that: The micro-electrode array comprises a central electrode and surrounding electrodes, wherein the central electrode is a stimulating electrode and the surrounding electrodes are inhibitory electrodes. The inhibitory electrode applies a unidirectional wave opposite to that of the stimulating electrode, and the current amplitude is smaller than that of the stimulating electrode.

8. The electrical stimulation tactile perception evaluation interactive system according to claim 7, characterized in that: The ratio of the current of the inhibitory electrode to the current of the stimulating electrode is 1:

4.

9. The electrical stimulation tactile perception evaluation interactive system according to claim 6, characterized in that: The micro-electrode array adopts a 3×4 12-point electrode array layout, and the electrodes are square electrodes.

10. The electrical stimulation tactile perception evaluation interactive system according to claim 6, characterized in that: The micro-electrode array is arranged on a fabric substrate, and the fabric substrate is obtained by compounding a TPU insulating film and a nylon substrate.

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