Method and system for evaluating haptic perception based on electrohaptics virtual reality

Abstract

The application belongs to the technical field of virtual reality, and specifically discloses a kind of tactile sensation perception evaluation method and system based on electrohaptics virtual reality, which comprises the following steps: S1, user wears VR glasses and wears micro electrode array on finger, opens VR glasses and enters virtual scene;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 stimulating current according to the pattern of the blocked virtual pattern to trigger the micro electrode array on the finger issuing a click instruction;S3, the user feeds back the pattern shape that it 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 sensation perception ability level. By using the technical scheme, high spatial resolution and flexible tactile stimulation are realized through the surrounding inhibition structure, various tactile patterns can be accurately simulated, and users can experience rich tactile perception tasks in a virtual environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of virtual reality, and relates to a haptic perception evaluation method and system based on electrohaptic virtual reality. BACKGROUND

[0002] Haptics, as one of the five senses, 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 virtual reality (VR) and augmented reality (AR) technologies, the interactive experience in the digital world is becoming richer and richer. However, current digital interaction mostly relies on vision and hearing, and the lack of haptic feedback limits the user's immersion and interaction accuracy in the virtual environment.

[0003] In the aspect of virtual haptic generation, although there has been significant progress, the improvement of haptic simulation and perception ability is still a technical challenge to be broken through.

[0004] Existing haptic feedback mostly relies on mechanical devices, which can simulate certain physical touch, but often have large volume, complex structure, and are difficult to accurately control and achieve portability. In contrast, electrohaptic stimulation, due to its precise control of intensity, frequency and duration, has become a more suitable means of haptic feedback for virtual environments. Micro-current regulation not only allows independent stimulation of each electrode, but also reduces user interference and is highly safe, making it very suitable for virtual haptic training and long-term interaction tasks.

[0005] In addition, the user group with reduced haptic perception sensitivity or impaired perception ability due to nerve damage also urgently needs effective haptic perception evaluation and training methods to improve their haptic sensitivity in daily life. However, existing haptic evaluation methods mostly rely on simple touch or physical tests, lack flexible and personalized dynamic training scenarios, and are difficult to fully meet individual needs. Therefore, designing a haptic feedback system that is adapted to virtual environments, reusable and can provide accurate quantitative evaluation has become a problem to be solved. SUMMARY

[0006] The purpose of the present application is to provide a haptic perception evaluation method and system based on electrohaptic virtual reality, which realizes high spatial resolution and flexible haptic stimulation through a surround-inhibiting structure, can accurately simulate various haptic patterns, and supports users to experience rich haptic perception tasks in a virtual environment.

[0007] In order to achieve the above purpose, the basic scheme of the present application is: a haptic perception evaluation method based on electrohaptic virtual reality, comprising the following steps:

[0008] S1, the user wears VR glasses and a micro electrode array on the finger, turns on the VR glasses to enter a virtual scene, and clicks on a virtual pattern that is blocked in the virtual scene with the finger wearing the micro electrode array;

[0009] 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 stimulating current to trigger the micro electrode array on the finger that clicks the instruction according to the pattern of the blocked virtual pattern;

[0010] 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 level of tactile perception ability.

[0011] The working principle and beneficial effects of the basic scheme are that the technology simulates a variety of tactile patterns on the electrode array through current, and the subject can perform diversified tactile perception tasks in a virtual environment. Compared with traditional scale evaluation or touch sandpaper test method, the method is more convenient, can accurately quantify tactile perception ability, reduces cost, and supports diversified virtual training scenes.

[0012] The technology has wide application potential in medical rehabilitation, VR and AR immersive experience, etc. It provides a safe and non-invasive training platform for groups with reduced tactile sensitivity. Although the system cannot directly restore the tactile perception ability of the user, through a series of accurate tactile perception tasks and virtual training, the tactile sensitivity of the user in the immersive virtual environment can be effectively improved, and scientific quantitative evaluation can be realized.

[0013] Further, in steps S1 and S2, based on the virtual scene, the subject clicks on a plurality of virtual boxes of blocked information, and the first controller obtains the clicking information and stimulates the tactile corpuscles of the fingertip 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 of the fingertip, and the second controller records the results and reaction time of the judgment to quantify the tactile perception ability of the subject;

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

[0016] The electrode array worn on the index finger of the user simulates a variety of tactile patterns through the micro current provided by the electric stimulator, and the VR glasses serve as a bridge for visual communication. The tactile perception accuracy and reaction time of the subject can be improved.

[0017] Further, the first controller generates a micro-electrode array on the finger issuing a click instruction according to the pattern of the blocked virtual pattern, and the method is:

[0018] S31, obtaining a pattern shape, and dividing 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 for a first time, and the user feeds back the pattern shape to the second controller according to the feeling;

[0020] S33, the first controller issues a control command to only stimulate the key stimulation area for a second time, and the user feeds back the pattern shape to the second controller according to the feeling;

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

[0022] S35, the second controller generates a final feedback according to the feedback of the three times.

[0023] The first controller generates a micro-electrode array on the finger issuing a click instruction according to the pattern of the blocked virtual pattern, which is beneficial to use.

[0024] Further, the second controller compares the real pattern shape, the pattern shape fed back by the user, and the reaction time, and the method for calculating the tactile perception ability is:

[0025] S41, obtaining the pattern fed back by the user and the real pattern;

[0026] S42, adjusting the pattern fed back by the user and the real pattern to the same size and corresponding;

[0027] S43, taking the points of the real pattern as a template, and corresponding the points in the pattern fed back by the user, if there is no corresponding point in the pattern fed back by the user, adding the point in the pattern fed back by the user and setting 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, deleting the point in the pattern fed back by the user;

[0028] S42, calculating the feedback error E of the pattern shape, and N is the total number of points of the real pattern:

[0029]

[0030] wherein N is the total number of points of the real pattern, k is the total number of points deleted in the pattern of user feedback, 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 real pattern, 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 real pattern, 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:

[0031]

[0032] wherein a is an adjustment factor, which can be set, T is the reaction time, E0 is the diameter size of the real pattern, and T0 is the standard reaction time.

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

[0034] Further, the following steps are further included:

[0035] The Euclidean distance method is used to evaluate the difficulty of different tactile patterns, and the specific method is:

[0036] The recognition accuracy and reaction time data of the subject to the tactile pattern are standardized and scaled to the interval [-1, 1];

[0037] The overall average accuracy and reaction time of each pattern are used as coordinate axes, the horizontal coordinate interval is set to [2, -2], the vertical coordinate 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 perceive and recognize;

[0038] The Euclidean distance of each pattern is calculated, and the group with the best accuracy and reaction time is used as the reference pattern, and the difficulty of each pattern is defined as 1 point;

[0039] According to the relative Euclidean distance ratio of other patterns to the reference pattern, the difficulty score of each pattern is calculated, and the specific score is:

[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 pattern, and a quantitative and difficulty-based tactile perception ability evaluation framework is provided.

[0042] The application provides a quantitative, difficulty-based haptic perception ability evaluation framework, and provides a better basis for haptic quantitative evaluation.

[0043] The application also provides an electric stimulation haptic perception evaluation interactive system based on the method.

[0044] The micro electrode array is worn on the fingertip of a user, and the electrode array serves as an anode in the feedback haptic area, i.e., the fingertip, and the electrode array on the back of the finger serves as a common cathode.

[0045] The electric stimulation generator generates a pulse current for each electrode of the micro electrode array, wherein the stimulation electrode is connected to a positive current, and the inhibition electrode is connected to a negative current.

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

[0047] The processing unit is connected to the micro electrode array, the electric stimulation generator and the VR glasses, and comprises a first controller and a second controller.

[0048] The system combines the micro electrode array, the electric stimulation generator, the haptic evaluation rule and the virtual scene to construct a safe, non-invasive and reusable haptic perception evaluation interactive system, and provides convenient and specific haptic quantitative evaluation and personalized training for the user.

[0049] Further, the micro electrode array comprises a center electrode and a surrounding electrode, the center electrode is a stimulation electrode, the surrounding electrode is an inhibition electrode, the inhibition electrode applies a unidirectional wave opposite to the stimulation electrode, and the current amplitude of the inhibition electrode is smaller than that of the stimulation electrode.

[0050] In this way, the diffusion of the stimulation current is restrained, the interference is reduced, the charge accumulation is offset, and the numbness is delayed.

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

[0052] When the inhibition current amplitude is 1 / 4 of the stimulation current, the current density of the center electrode area is most concentrated, and the amplitude ratio of the inhibition current to the stimulation current is optimized.

[0053] Further, the micro electrode array adopts a 3x4 12-point electrode array layout, and the electrode adopts a square electrode.

[0054] The square electrode performs better in current concentration, based on the research of the size of the normal human touch sensitive area (about 1-1.5cm 2 ) and the two-point touch threshold (2-4mm), a 3x4 12-point electrode array layout is selected, and the touch perception effect is better.

[0055] Further, 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.

[0056] The fabric substrate is used for insulating protection and packaging of the electrode area, and has soft texture and high comfort. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 is a flowchart of the touch perception evaluation method of the electric haptic virtual reality of the present application;

[0058] Figure 2 is a simulation change diagram of the stimulating current of the electric stimulation touch perception evaluation interactive system of the present application;

[0059] Figure 3 is a standard deviation distribution diagram of the touch cognitive ability score of the subject of the touch perception evaluation method of the electric haptic virtual reality of the present application. DETAILED DESCRIPTION

[0060] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the present application, and cannot be understood as a limitation of the present application.

[0061] In the description of the present application, it should be understood that the terms "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0062] In the description of the present application, unless otherwise specified and limited, it is necessary to explain that the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be mechanical connection or electrical connection, it can be the communication inside two elements, it can be direct connection or indirect connection through intermediate medium, and the specific meaning of the above terms can be understood by the person skilled in the art according to the specific circumstances.

[0063] The application discloses a kind of based on electrohaptics virtual reality's tactile perception evaluation method, as Figure 1 As shown in the figure, comprising the following steps:

[0064] S1, user wears VR glasses and wears microelectrode array in finger, opens VR glasses (the virtual finger generated by Ultra Leap 3D technology in VR glasses will touch the pattern on screen) enters virtual scene, and clicks the virtual pattern that is obscured in virtual scene with finger wearing microelectrode array;

[0065] S2, the first controller obtains the pattern of the obscured virtual pattern clicked by user and transmits to the second controller, and the first controller generates stimulating current (selects suitable micro-current gear, such as 1mA, 2mA or 4mA) according to the pattern of the obscured virtual pattern to trigger microelectrode array on the finger that clicks instruction;

[0066] S3, user feeds back the pattern shape that it feels (specific user can draw or click corresponding image selection button to determine the pattern shape that it feels and transmits to the second controller) to the second controller, and the second controller compares real pattern shape, user feedback pattern shape and reaction time to calculate tactile perception ability level.

[0067] In a preferred scheme of the application, in steps S1 and S2, based on virtual scene, the subject clicks a plurality of virtual boxes (which can be marked as "+") of obscured information, the first controller obtains the clicking information and stimulates the tactile corpuscle of fingertip through electrode array, to form tactile sensation corresponding to virtual pattern;

[0068] The subject judges the pattern shape perceived in fingertip tactile feedback, and the second controller records the results of its judgment and reaction time to quantify 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, and repetitive electrical stimulation pattern simulation training can effectively improve the tactile perception ability score, and gradually improve the tactile sensitivity of the subject in immersive virtual environment.

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

[0071] S31, Obtain the pattern shape and divide the pattern into key stimulus areas, general stimulus areas, and non-stimulation areas. Pattern shapes include simple lines (e.g., horizontal line segments, vertical line segments, left-sloping line segments, right-sloping line segments), geometric shapes (e.g., crosses, X shapes, squares, rectangles), and complex shapes (e.g., smiley faces, sad faces, etc.). Simple line shapes primarily test the perception of direction and length, geometric shapes introduce elements of shape and spatial relationships, and complex shapes involve multiple visual features such as points, lines, angles, and symmetry. Specifically, areas outside the pattern can be designated as non-stimulation areas, the intersections of pattern boundary points and lines within the pattern as key stimulus areas, and the rest as general stimulus 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 continue for the first time, and the user provides feedback to the second controller on the pattern shape he / she feels.

[0073] S33, the first controller issues a control command to stimulate only the key stimulation area and continue for a second time, and the user provides feedback to the second controller on the pattern shape of their sensation.

[0074] S34, the first controller sends a stimulation signal of first intensity to the electrode of the key stimulation area and a stimulation signal of second intensity to the electrode of the general stimulation area for a third time. The first intensity is stronger than the second intensity. The user provides feedback to the second controller on the pattern shape he / she feels. The first time, the second time, and the third time can be the same or different, depending on the user's actual click event.

[0075] S35, the second controller generates the final feedback based on the three feedbacks. Specifically, the pattern that appears most frequently in the three feedbacks is the final feedback. If the number of feedbacks is the same, then the final feedback pattern is the final feedback. By distinguishing between key stimulus areas, general stimulus areas, and non-stimulation areas, the stimulation sensation in key areas can be highlighted, improving the accuracy of the user's perception.

[0076] In a preferred embodiment of the present invention, the method by which the second controller calculates the tactile perception capability by comparing the actual pattern shape, the pattern shape provided by the user, and the reaction time is as follows:

[0077] S41, obtain user-submitted patterns and real patterns;

[0078] S42, the user feedback pattern and the real pattern are adjusted to the same size and corresponding, for example, the size of the outer boundary can be adjusted to the same size, for example, the maximum value of the lateral size and the maximum value of the longitudinal size of the pattern are adjusted to be the same, and the key area is corresponding;

[0079] S43, taking the point of the real pattern as a template, the point in the user feedback pattern is corresponding, if there is no corresponding point in the user feedback pattern, the point is added in the user feedback pattern and the coordinate value of the point is set to 0; if there is a point in the user feedback pattern but no corresponding point in the real pattern, the point is deleted in the user feedback pattern;

[0080] S42, the feedback error E of the pattern shape is calculated:

[0081]

[0082] Wherein, N is the total number of points of the real pattern, k is the total number of points deleted in the user feedback pattern, 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 user perception pattern, S r (ix) is the x coordinate of the i th point of the real pattern, S u (iy) is the longitudinal coordinate of the i th point of the user perception pattern, S r (iy) is the longitudinal 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:

[0083]

[0084] Wherein, alpha is an adjustment factor, which can be set, T is the reaction time, E0 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), and T0 is the standard reaction time.

[0085] In a preferred scheme of the present application, the following steps are further provided:

[0086] The Euclidean distance method is used to evaluate the difficulty of different tactile patterns, and the specific method is:

[0087] The identification accuracy and reaction time data of the subject to the tactile pattern are standardized, and are scaled to the interval [-1, 1];

[0088] The overall average accuracy and reaction time of each pattern are taken as the coordinate axes, the horizontal coordinate interval is set to [2, -2], the vertical coordinate 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 identification accuracy of the pattern, the shorter the reaction time, and the easier the pattern is perceived and identified;

[0089] The Euclidean distance of each pattern is calculated, and the group with the best accuracy and reaction time is taken as the benchmark pattern, and the difficulty level is defined as 1 point;

[0090] According to the relative Euclidean distance ratio of other patterns to the benchmark pattern, the difficulty score of each pattern is calculated, and the specific score is:

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

[0092] The score is sorted according to the difficulty of pattern recognition from easy to difficult, providing a quantitative and difficulty-based evaluation framework for tactile perception ability.

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

[0094] The present application also provides an electrical stimulation tactile perception evaluation interactive system (TPE IS) based on the method of the present application, including a micro electrode array, an electrical stimulation generator, a VR glasses and a processing unit embedded with evaluation rules.

[0095] The micro electrode array is worn on the fingertip of the user, and in the feedback tactile area, i.e. the fingertip, the electrode array acts as an anode, and the electrode array on the back of the finger acts as a common cathode.

[0096] The electrical stimulation generator generates pulsed current for each electrode connected to the micro electrode array, in which the stimulating electrode (hydrogel patch electrode) is connected to the positive current, and the inhibitory electrode is connected to the negative current, and the VR glasses are worn on the eyes of the user. This design makes the current flow through the nerves on the side of the fingertip skin, achieving effective tactile feedback, and since the density of mechanoreceptors in the back of the finger is much lower than that in the palm of the hand, the back of the finger will not cause tactile stimulation, thereby avoiding interference.

[0097] The processing unit is connected with the micro electrode array, the electric stimulation generator and the VR glasses, and the processing unit comprises a first controller and a second controller, the first controller acquires the pattern of the blocked virtual pattern clicked by the user and transmits the pattern to the second controller, the first controller generates the micro electrode array on the finger triggering the click instruction according to the pattern of the blocked virtual pattern, 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 level of tactile perception ability.

[0098] In a preferred scheme of the present application, the accurate resolution of tactile perception ability is disturbed by the current diffusion characteristics. The current diffusion will affect the accuracy of tactile perception and may cause a certain degree of numbness.

[0099] To solve this problem, the micro electrode array comprises a center electrode and a surrounding electrode, the center electrode is a stimulation electrode, the surrounding electrode is a suppression electrode, the suppression electrode applies a unidirectional wave opposite to the stimulation electrode, and the current amplitude is smaller than that of the stimulation electrode. In this way, on the one hand, the diffusion of the stimulation current is restrained, and the interference is reduced; on the other hand, the charge accumulation is offset, and the numbness is delayed.

[0100] In the case of the suppression electrode, the accuracy of most subjects in identifying simple line patterns is significantly higher than that in the case without the suppression electrode.

[0101] In a preferred scheme of the present application, to optimize the amplitude ratio of the suppression and stimulation currents, the change of the suppression: stimulation current ratio from 0 to 1 is analyzed by COMSOL simulation, as shown in the following figure. Figure 2 When the amplitude of the suppression current is 1 / 4 of the stimulation current, the current density in the center electrode region is most concentrated, so the optimal ratio is determined: the current ratio of the suppression electrode to the stimulation electrode is 1:4. Preferably, the pulse frequency of the system is set to 500 Hz, the pulse width is 200 us, and the amplitude of the stimulation current is 2 mA. This current parameter can provide a comfortable tactile perception experience for most users.

[0102] In a preferred scheme of the present application, 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 normal people, the micro electrode array adopts a 3x4 12-point electrode array layout, and the electrode adopts a square electrode. Since the fabric substrate cannot support back wiring, the suppression electrode needs to open a gap for the introduction of the stimulation current. Through simulation comparison with and without the gap design, this adjustment does not affect the current density distribution.

[0103] In a preferred embodiment of the present application, the microelectrode array is arranged on a fabric substrate, which is obtained by compounding a TPU insulating film and a nylon substrate. The microelectrode array uses a platinum-carbon metal electrode (e.g., FZ-BT9505, Guangdong Fangzhou Manufacturing Technology Co., Ltd.), which is composed of nano-pure carbon powder, carbon nanotubes, and platinum gold powder. The nano-pure carbon powder provides basic electrical conductivity, the carbon nanotubes enhance the mechanical strength and flexibility of the electrode, and the platinum gold powder improves the chemical stability and corrosion resistance. The platinum-carbon metal electrode provides excellent electrical conductivity and wear resistance; the TPU insulating film has the characteristics of low cost and high durability, and is used for insulation protection and packaging of the electrode area.

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

[0105] Preferably, the fabric substrate is preferably made of nylon fabric, 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. Selecting nylon as the fabric substrate, the TPU insulating film is compounded with the nylon substrate through a high-temperature thermal compounding process to obtain a composite substrate with flexibility and wear resistance. The designed electrode array pattern is deposited on the composite substrate by screen printing process.

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

[0107] In this way, the microelectrode array is ultra-thin, soft and wearable. The electrode array worn on the index finger of the user simulates various tactile patterns through the micro-current provided by the electrical stimulator, and the VR glasses serve as a bridge for visual communication.

[0108] The system uses a microelectrode array on a fabric substrate, which realizes high spatial resolution and flexible tactile stimulation through a wrap-around suppression structure, can accurately simulate various tactile patterns, and supports users to experience rich tactile perception tasks in a virtual environment.

[0109] In the description of the specification, reference to "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" means that a particular feature, structure, material, or characteristic being described is included in at least one embodiment or example of the application. The appearances of the above expressions in various places in the specification are not necessarily referring to the same embodiment or example. Moreover, the particular features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0110] Although embodiments of the present application have been shown and described, it would be appreciated by those skilled in the art that changes, modifications, alternatives and variations to these embodiments could be made without departing from the principles and spirit of the application, the scope of which is defined in the claims and their equivalents.

Claims

1. A method for haptic perception assessment based on electrohaptics virtual reality, characterized in that, Comprise the following steps: S1, the user wears VR glasses and wears a micro electrode array on the finger, opens the VR glasses into a virtual scene, and clicks on the virtual pattern blocked in the virtual scene with the finger wearing the micro electrode array; S2, the first controller acquires the pattern of the blocked virtual pattern clicked by the user and transmits it to the second controller, and the first controller generates a stimulating current to trigger the micro electrode array on the finger issuing the click instruction according to the pattern of the blocked virtual pattern; 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 level of tactile perception ability; In steps S1 and S2, based on the virtual scene, the subject clicks on the virtual boxes of multiple blocked information, and the first controller acquires the click information and stimulates the tactile corpuscles of the fingertips through the electrode array to form a tactile feeling corresponding to the virtual pattern; The subject judges the pattern shape perceived in the tactile feedback of the fingertips, and the second controller records the results of its judgment and the reaction time to quantify the tactile perception ability of the subject; If the tactile perception ability of the subject is lower than the standard deviation level, provide repetitive tactile training to gradually improve the tactile sensitivity of the subject in the immersive virtual environment; The method for the second controller to compare the real pattern shape, the pattern shape fed back by the user, and the reaction time to calculate the tactile perception ability is: S41, acquire the pattern fed back by the user and the real pattern; S42, adjust the pattern fed back by the user and the real pattern to the same size and correspond; S43, take the points of the real pattern as a template, and correspond the points in the pattern fed back by the user, 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; S42, calculate the feedback error E of the pattern shape, N is the total number of points of the real pattern where N is the total number of points of the real pattern, k is the total number of points deleted in the pattern fed back 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 real pattern, 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 real pattern, d is the distance between the deleted point and the center point; the tactile perception ability C is: 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: Wherein, α is an adjustment factor, which can be set; T is the reaction time, E0 is the diameter size of the real pattern, and T0 is the standard reaction time. 2.The electrohaptics virtual reality based haptic perception evaluation method of claim 1, wherein, The method for the first controller to generate a stimulating current to trigger the micro electrode array on the finger issuing the click instruction according to the pattern of the blocked virtual pattern is: S31, acquire the pattern shape, divide the pattern into key stimulation area, general stimulation area and non-stimulation area; S32, the first controller issues a control command and simultaneously stimulates 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 issues a stimulating signal of a first intensity to the electrodes of the key stimulation area and a stimulating signal of a second intensity to the electrodes corresponding to the general stimulation area for a third time, and the first intensity is stronger than the second intensity, and the user feeds back the pattern shape he feels to the second controller; S35, the second controller generates the final feedback according to the feedback of the three times. 3.The electrohaptics virtual reality based haptic perception evaluation method of claim 1, wherein, Further comprising the following steps: The difficulty of different tactile patterns is evaluated by using the Euclidean distance method. The specific method is as follows: The recognition accuracy and reaction time data of the subjects to the tactile patterns are standardized and scaled to the interval [-1, 1]; The overall average accuracy and reaction time of each pattern are taken as the coordinate axes, the horizontal coordinate interval is set as [2, -2], the vertical coordinate interval is set as [-2, 2], and the origin is set as (2, -2). The closer the coordinate point is to the origin, the higher the recognition accuracy and the shorter the reaction time, indicating that the pattern is easy to perceive and recognize; The Euclidean distance of each pattern is calculated, and the group with the best accuracy and reaction time performance is taken as the reference pattern, and the difficulty is defined as 1 point; According to the relative Euclidean distance ratio of other patterns to the reference pattern, the difficulty score of each pattern is calculated, and the specific score is: ′Group 1′:1.5,′Group 2′:1.0,′Group 3′:2.75,′Group 4′:3.06,′Group 5′:4.28; The scores are sorted from easy to difficult according to the recognition difficulty of the patterns, providing a quantitative and difficulty-based tactile perception ability evaluation framework.

4. An electro-stimulation haptic perception evaluation interactive system based on the method according to one of claims 1 to 3, characterized in that, It includes a micro electrode array, an electric stimulation generator, a VR glasses and a processing unit embedded with evaluation rules; The micro electrode array is worn on the user's fingertip, and in the feedback tactile area, i.e. the fingertip, the electrode array acts as an anode, and the electrode array on the back of the finger acts as a common cathode; The electric stimulation generator generates pulse current for each electrode connected to the micro electrode array, wherein the stimulation electrode is connected to the positive current, and the suppression electrode is connected to the negative current; The VR glasses are worn on the user's eyes; The processing unit is connected to the micro electrode array, the electric stimulation generator and the VR glasses, and includes a first controller and a second controller. The first controller acquires 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 to trigger the micro electrode array on the finger that clicks the instruction according to the pattern of the blocked virtual pattern. The user feeds back the pattern shape he feels to the second controller. The second controller compares the real pattern shape, the user's feedback pattern shape and the reaction time to calculate the tactile perception ability level.

5. The electrical stimulation tactile perception assessment interactive system of claim 4, wherein, The micro electrode array includes a center electrode and a surrounding electrode. The center electrode is a stimulation electrode, and the surrounding electrode is a suppression electrode. The suppression electrode applies a unidirectional wave opposite to the stimulation electrode, and the current amplitude is smaller than that of the stimulation electrode.

6. The electrical stimulation tactile perception assessment interactive system of claim 5, wherein, The current ratio of the suppression electrode to the stimulation electrode is 1:

4.

7. The electrical stimulation tactile perception assessment interactive system of claim 4, wherein, The micro electrode array adopts a 3x4 12-point electrode array layout, and the electrodes adopt square electrodes.

8. The electrical stimulation tactile perception assessment interactive system of claim 4, wherein, The micro electrode array is arranged on a fabric substrate, and the fabric substrate is obtained by compounding a TPU insulating film and a polyamide substrate.

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