Virtual friction tactile rendering method and device based on microcurrent stimulation

Abstract

The present invention relates to the technical field of human-computer interaction and tactile rendering, and is a virtual friction tactile rendering method and device based on microcurrent stimulation, the method comprising obtaining the friction tactile interaction information of a real object and the hand motion information of an interactor, and mapping them to a virtual object and a virtual hand; defining the friction interaction state between the virtual hand and the surface of the virtual object, and designing a tactile feedback array that provides corresponding stimulation modes for different friction interaction states; when the virtual hand begins to contact the surface of the virtual object, the stimulation mode is converted to a contact mode; when the virtual hand begins to slide on the surface of the virtual object, the stimulation mode is converted to a sliding mode; when the virtual hand leaves the surface of the virtual object, the stimulation mode is converted to a separation mode; in a virtual scene, the interactor perceives the real surface information of various objects from three feedback channels of audio, video and touch through friction interaction processes such as contact, sliding and separation, and realizes an immersive interactive experience. The present invention improves the sense of reality and immersion of virtual friction tactile.

Description

Technical Field

[0001] The present invention relates to the technical field of human-computer interaction and tactile rendering, and in particular to a virtual friction tactile rendering method and device based on micro-current stimulation. Background Art

[0002] With the continuous development of virtual reality technology (VR), people's demand for immersive experience is growing. At present, although audio-visual feedback technology has made significant progress, there is a general lack of tactile feedback, which is essential for enhancing realism and immersion. Traditional mechanical tactile feedback devices are often bulky and slow to respond, which limits the improvement of user experience. In contrast, tactile rendering technology based on microcurrent stimulation has the advantages of simple and compact device and fast response, showing great potential and application prospects.

[0003] The current tactile rendering technology based on microcurrent stimulation still faces challenges in terms of virtual tactile realism. Most technical rendering effects have a low correlation with real objects. Usually, they can only apply simple stimulation to allow the interactor to perceive the existence of virtual objects, but cannot reproduce the real tactile interaction process and the surface characteristics of objects in the virtual world. In addition, the existing tactile feedback arrays are mostly strictly arranged in a matrix, which is not conducive to the rendering of multiple tactile modalities and does not conform to the physiological characteristics of different sensitivities in different areas of human fingers. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a virtual friction tactile rendering method and device based on microcurrent stimulation, which adopts microcurrent stimulation based on the surface characteristics of real objects, decomposes the friction process of feeling the surface characteristics of objects into three stages: contact, sliding and separation, and reproduces the process of friction interaction perception between people and objects in the real world in the virtual world through three feedback channels of vision, hearing and touch, and designs an electrode array that is more in line with the physiological characteristics of human touch, so as to achieve a more realistic and immersive virtual friction tactile interaction experience.

[0005] To achieve the above object, the present invention provides a virtual friction tactile rendering method based on microcurrent stimulation, comprising the following steps:

[0006] S1, obtaining friction tactile interaction information of a real object and hand motion information of an interactor, generating a corresponding virtual object in a virtual scene according to the friction tactile interaction information, and mapping the hand motion information of the interactor to a virtual hand in the virtual scene;

[0007] S2. defining the friction interaction state between the virtual hand and the surface of the virtual object, wherein the defined friction interaction state includes contact between the virtual hand and the surface of the virtual object, sliding of the virtual hand on the surface of the virtual object, and separation of the virtual hand from the surface of the virtual object; designing a tactile feedback array, wherein the designed tactile feedback array provides corresponding stimulation modes for different friction interaction states, wherein the stimulation modes include contact mode, sliding mode, and separation mode, so as to render the virtual touch during the friction interaction between the virtual hand and the surface of the virtual object;

[0008] S3, real-time detection of the friction interaction state between the virtual hand and the surface of the virtual object. When the virtual hand begins to contact the surface of the virtual object, the stimulation mode is switched to the contact mode. During the contact and pressing process of the virtual hand, the contact position between the virtual hand and the surface of the virtual object is used as the stimulation area according to the relative contact depth between the virtual hand and the surface of the virtual object and the softness of the surface of the virtual object. A gradually increasing pressure sense is applied at the center of the stimulation area to render the trend of increasing stress during the pressing process of the virtual hand. At the same time, a vibration sense that expands the boundary from the inside to the outside is applied to render the deformation process of the virtual hand skin from the inside to the outside during the pressing process of the virtual hand.

[0009] S4, when the virtual hand starts to slide on the surface of the virtual object, the stimulation mode is switched to the sliding mode, the stimulation area is determined according to the pressing depth during the sliding process, and a vibration feeling with a dynamically changing vibration frequency is given in the stimulation area according to the sliding speed and the roughness of the surface of the virtual object;

[0010] S5. When the virtual hand leaves the surface of the virtual object, the stimulation mode switches to the separation mode. During the process of the virtual hand separating and lifting from the surface of the virtual object, a gradually decreasing pressure sensation is applied at the center of the stimulation area according to the degree of separation between the virtual hand and the surface of the virtual object and the softness of the surface of the virtual object to render the trend of stress decreasing during the lifting of the virtual hand. At the same time, a vibration sensation that shrinks the boundary from the outside to the inside is applied to render the deformation process of the virtual hand skin from the outside to the inside during the lifting of the virtual hand.

[0011] The present invention also provides a virtual friction tactile rendering device based on microcurrent stimulation, which is implemented based on the above rendering method and includes:

[0012] An interaction information acquisition module is used to obtain the friction tactile interaction information between the real-world hand and the real object and the hand movement information of the interactor;

[0013] An interactive rendering control module is used to map the acquired friction tactile interaction information and hand motion information to virtual objects and virtual hands in a virtual scene, render the virtual scene in real time, monitor the friction interaction state of the virtual hand and virtual objects in the virtual scene, and issue corresponding feedback instructions according to different friction interaction states and interaction parameters;

[0014] The multi-channel interactive feedback module is used to provide three feedback experiences including vision, hearing and touch. The visual feedback is achieved by real-time rendering of virtual scenes in front of the eyes of the interactor. The auditory feedback is achieved by providing corresponding friction sound information in sliding mode. The tactile feedback applies micro-current stimulation of different modes to the tactile feedback array according to the received feedback instructions to simulate the process of friction interaction.

[0015] Compared with the prior art, the beneficial effects of the present invention include:

[0016] 1. The present invention adopts the friction tactile interaction information obtained from the surface characteristics of real objects, and reproduces the process of friction interaction perception between people and objects in the real world in the virtual world through the three feedback channels of vision, hearing and touch through the combination of different stimulation modes and the adjustment of stimulation parameters according to the surface characteristics, thereby improving the realism and immersion of virtual touch.

[0017] 2. Compared with the traditional matrix electrode array, the finger multilayer electrode array designed by the present invention is more in line with the physiological characteristics of the gradual change of the tactile sensitivity of human fingers from the fingertips to the surrounding areas, so it can more accurately simulate and reproduce various complex tactile interaction processes. In addition, the designed finger multilayer electrode array has three stimulation modes, namely contact mode, sliding mode and separation mode, which are in line with the process and characteristics of interacting with objects in the real world.

[0018] 3. The device of the present invention has a simple structure, low power consumption, and can be used wirelessly by users, thereby improving the freedom and comfort of the interactive experience and meeting the usage requirements in different scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of a flow chart of a virtual friction tactile rendering method based on microcurrent stimulation provided by an embodiment of the present invention;

[0020] Figure 2 A vertical elliptical multilayer electrode array for rendering tactile sensation on a finger provided by an embodiment of the present invention, wherein the electrodes connected by dotted lines are in the same layer;

[0021] Figure 3 Schematic diagram of the contact mode process involved in an embodiment of the present invention, wherein a blank electrode indicates inactivity, a completely black electrode indicates receiving a cathode stimulation signal, and a black striped electrode indicates receiving an anode stimulation signal;

[0022] Figure 4 Schematic diagram of the sliding mode involved in an embodiment of the present invention, wherein a blank electrode indicates inactivity, a completely black electrode indicates receiving a cathode stimulation signal, and a black striped electrode indicates receiving an anode stimulation signal; the pressing depths of (a) and (b) are different, thereby activating different electrode layers;

[0023] Figure 5 It is a schematic diagram of the separation mode process involved in an embodiment of the present invention, wherein a blank electrode indicates inactivation, a completely black electrode indicates receiving a cathode stimulation signal, and a black striped electrode indicates receiving an anode stimulation signal.

[0024] Figure 6 A schematic diagram of the structure of a virtual friction tactile rendering device based on microcurrent stimulation provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be described in detail below with reference to the accompanying drawings and embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the scope of protection and implementation methods of the present invention.

[0026] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0027] Furthermore, in this specification and the drawings, unless expressly stated otherwise, “connection” does not necessarily mean “direct connection” or “direct contact”; here, “connection” may refer to both a fixed function and electrical connectivity.

[0028] Example 1

[0029] See also Figure 1 The virtual friction tactile rendering method based on microcurrent stimulation provided in this embodiment includes the following steps:

[0030] Step S1, obtaining friction tactile interaction information of a real object and hand motion information of an interactor, generating a corresponding virtual object in a virtual scene according to the friction tactile interaction information, and mapping the hand motion information of the interactor to a virtual hand in the virtual scene.

[0031] Specifically, the friction tactile interaction information of real objects includes surface pattern distribution information, sound information of hand rubbing on its surface, and roughness and softness parameter information.

[0032] Among them, the surface pattern distribution information and roughness and softness parameter information can be collected by using a visual tactile sensor of model Gelsight. The Gelsight visual tactile sensor uses its soft elastomer contact surface to capture the pattern distribution and geometric shape of the object surface with extremely high spatial resolution, and performs 3D modeling and roughness, softness and other parameter calculations on the software. The sound information of fingers rubbing on the surface of the object can be collected by using a sound vibration measurement system of model SQuadriga III. The SQuadriga III sound vibration measurement system can record up to 8 channels of analog signals and collect sound and vibration data by connecting different types of sensors, such as microphones and accelerometers. The collection of these data provides the system with rich tactile interaction information.

[0033] A gesture capture camera may be used to capture the hand motion information of the interactor in real time, and the hand motion data of the interactor may be parsed according to the captured hand motion information and converted into the motion of a virtual hand in a virtual scene.

[0034] Step S2, defining the friction interaction state between the virtual hand and the surface of the virtual object, the defined friction interaction state includes the virtual hand contacting the surface of the virtual object, the virtual hand sliding on the surface of the virtual object, and the virtual hand leaving the surface of the virtual object; designing a tactile feedback array, the designed tactile feedback array provides corresponding stimulation modes for different friction interaction states, the stimulation modes include contact mode, sliding mode and separation mode, so as to render the virtual touch during the friction interaction between the virtual hand and the surface of the virtual object.

[0035] In this embodiment, there is an entire virtual hand in the virtual scene; since the electrode array for tactile feedback is preferably arranged on the fingers, the tactile feedback has the highest accuracy. Therefore, the optimal technical solution is to detect whether the virtual finger has contacted, slid, or other friction interactions with the surface of the virtual object to stimulate the tactile feedback array.

[0036] like Figure 2 As shown, in this embodiment, a finger multilayer electrode array is designed as a tactile feedback array, and the finger multilayer electrode array includes a ground electrode and a multilayer stimulation electrode array. The ground electrode is rectangular, with a size of 1×1.5 cm, and is located on the back of a finger (such as an index finger), and the center of the ground electrode is located proximal to the middle of the nail bed groove of the index finger.

[0037] The multi-layer stimulation electrode array includes a first layer of stimulation electrodes, a second layer of stimulation electrodes, and a third layer of stimulation electrodes. The first layer of stimulation electrodes is located at the center of the fingertips; in this embodiment, the first layer of stimulation electrodes preferably includes 1 stimulation electrode. The second layer of stimulation electrodes is arranged around the first layer of stimulation electrodes and is distributed in an elliptical shape, with the major axis of the ellipse along the length direction of the finger and the minor axis of the ellipse along the width direction of the finger, that is, the second layer of stimulation electrodes is an elliptical distribution arranged vertically; in this embodiment, the second layer of stimulation electrodes preferably includes 4 stimulation electrodes, the major axis radius of the ellipse is 3.6mm, the minor axis radius is 2.8mm, and the 4 electrodes are located at both ends of the major axis and the minor axis. The third layer of stimulation electrodes is arranged around the second layer of stimulation electrodes and is distributed in an elliptical shape, with the major axis of the ellipse along the length direction of the finger and the minor axis of the ellipse along the width direction of the finger, that is, the third layer of stimulation electrodes is also an elliptical distribution arranged vertically; in this embodiment, the third layer of stimulation electrodes preferably includes 8 stimulation electrodes, the major axis radius of the ellipse is 8.1mm, and the minor axis radius is 5.6mm, of which 4 electrodes are located at both ends of the major axis and the minor axis, and the remaining 4 are located at the diagonal positions of the ellipse. In addition, a single stimulation electrode may be a circular stimulation electrode, each having a diameter of 1.8 mm.

[0038] That is to say, the multiple stimulation electrodes of the multi-layer stimulation electrode array are arranged in a vertical elliptical shape as a whole, and are divided into three layers around the center of the fingertip (such as the center of the index finger), namely the first layer, the second layer and the third layer.

[0039] In this embodiment, for each layer of stimulation electrodes of the multi-layer stimulation electrode array, each layer of stimulation electrodes adopts the same stimulation mode, and different layers of stimulation electrodes adopt different stimulation modes, and the stimulation modes include anode stimulation and cathode stimulation. Therefore, on the whole, the multi-layer stimulation electrode array adopts a spatiotemporal combination of anode stimulation and cathode stimulation, thereby rendering a virtual tactile experience of various friction interaction states on the finger.

[0040] In this embodiment, the virtual tactile sense based on micro-current stimulation mainly includes two basic tactile senses, namely pressure sense and vibration sense. Both pressure sense and vibration sense are achieved by applying micro-current stimulation to the fingers, that is, by applying micro-current stimulation to the multi-layer electrode array of the fingers.

[0041] Specifically, the sense of pressure is achieved through cathodic stimulation, which uses negative constant current electrical pulses of preset intensity and preset frequency. It can more effectively depolarize the nerve fibers of Merkel cells parallel to the skin surface. Merkel cells can respond to external mechanical pressure and ultimately produce a sense of pressure; and the receptive field is relatively diffuse, that is, the sense of pressure generated will be relatively divergent around the stimulated position. Therefore, the rendering characteristic of cathodic stimulation is a sense of pressure that is diffused around the stimulated position.

[0042] The sense of vibration is achieved through anodal stimulation, which uses a positive constant current electric pulse with a preset intensity and a preset frequency. It can more effectively depolarize the nerve fibers of the Meissner corpuscles perpendicular to the skin surface. The Meissner corpuscles can respond to external vibrations and ultimately produce a sense of vibration. The receptive field is more concentrated, that is, the sense of vibration generated will be limited to a certain range, and the boundaries of the stimulated position are clear. Therefore, the rendering characteristics of anodal stimulation are a sense of vibration with clear boundaries.

[0043] In addition, since the nerve fibers of Meissner's corpuscles are stimulated in anodal stimulation, and Meissner's corpuscles only respond significantly to low-frequency vibrations (such as in the range of 0-100Hz), the vibrations produced by anodal stimulation are also limited in frequency range. For anodal stimulation above 100Hz, the interactant perceives a continuous sense of contact but cannot feel a clear sense of vibration.

[0044] Further, in the description of this embodiment, regarding the selected stimulation intensity, if not otherwise stated, the pulse width of the cathode stimulation and the anode stimulation are both 200us, and the frequency of the cathode stimulation is 200Hz; the current amplitudes of the cathode stimulation and the anode stimulation are both:

[0045] ;

[0046] Where Ix is the current amplitude of the applied stimulation, Imax is the upper limit of the current perception threshold of the interactor, that is, the current amplitude when the pain is felt, and Imin is the lower limit of the current perception threshold of the interactor, that is, the current amplitude when the pain is just felt. It should be noted that different layers of stimulation electrode arrays have different Imax and Imin, so Ix is also different, which is related to the tactile sensitivity of the finger (such as the index finger). The overall trend is that the center of the fingertip is the most sensitive, and the sensitivity gradually decreases around the fingertip.

[0047] Step S3, real-time detection of the friction interaction state between the virtual hand and the surface of the virtual object. When the virtual hand (such as a virtual finger) begins to contact the surface of the virtual object, the stimulation mode is switched to the contact mode. During the contact and pressing process of the virtual hand, the contact position between the virtual hand and the surface of the virtual object (such as the fingertip of the virtual finger) is used as the stimulation area according to the relative contact depth between the virtual hand and the surface of the virtual object and the softness of the surface of the virtual object. A gradually increasing sense of pressure is applied at the center of the stimulation area (such as the center of the fingertip) to render the trend of increasing stress during the pressing process of the virtual hand. At the same time, a sense of vibration that expands the boundary from the inside to the outside is applied to render the deformation process of the virtual hand skin from the inside to the outside during the pressing process of the virtual hand.

[0048] In the contact mode, the change of virtual hand pressure stress is achieved by applying cathode stimulation with varying intensity at the center of the stimulation area, and the virtual hand skin deformation is achieved by applying anode stimulation at the boundary of the expanded stimulation area. The stimulation characteristics of the contact mode are related to the object softness parameter. The softer the object, the smaller the stress change, that is, the smaller the change in cathode stimulation intensity, and the faster the stimulation area expands, that is, the faster the boundary switching of applying anode stimulation.

[0049] Specifically, if Figure 3 As shown, when it is detected that the virtual hand (such as a virtual finger) begins to contact the surface of the virtual object, that is, from S31 to S32, the stimulation mode is switched to the contact mode. Since the point where the virtual finger begins to contact the surface of the virtual object is the most prominent position of the finger pulp, that is, the center of the finger pulp, an anode stimulation with a frequency of 120Hz is applied to a single electrode of the first layer of stimulation electrodes (i.e., the inner layer) of the tactile feedback array to render the touch feeling when just contacted; from S32 to S34, as the finger is pressed down, the electrodes are activated from the first layer of stimulation electrodes to the second layer of stimulation electrodes and the third layer of stimulation electrodes (i.e., the inner layer to the outer layer), and due to the gradually expanding skin deformation at the contact part of the finger, the stress at the center of the stimulation area also gradually increases, so an anode stimulation of 120Hz is applied to the stimulation electrode located at the gradually expanding boundary layer to render the boundary of the outward deformation, and at the same time, a cathode stimulation with an increasing intensity is applied to the stimulation electrode located in the boundary layer to render the increase in pressure. The current amplitude of the cathode stimulation varies from Imin to Ix. The softer the virtual object is, the smaller the stress change is, that is, the smaller the change in cathode stimulation intensity is, and the faster the stimulation area expands, that is, the faster the boundary switching of applying anode stimulation is.

[0050] Step S4: When the virtual hand starts to slide on the surface of the virtual object, the stimulation mode is switched to the sliding mode, the stimulation area is determined according to the pressing depth during the sliding process, and a vibration feeling of a preset vibration frequency is given to the stimulation area.

[0051] This step can also adjust the vibration frequency of the stimulation according to the sliding speed of the virtual hand and the surface roughness parameters of the virtual object.

[0052] In the sliding mode, anode stimulation of a preset frequency is applied to the stimulation area to achieve a vibration feeling of sliding across the surface of the virtual object. The vibration frequency of the anode stimulation is f Depends on the virtual hand sliding speed v and the surface roughness parameters of the virtual object λ .

[0053] Specifically, if Figure 4As shown in the figure, when the virtual hand starts to slide on the surface of the virtual object, it switches to the sliding mode. The size of the stimulation area is related to the pressing depth of the virtual hand. 41 is a case of shallow pressing, and 42 is a case of deep pressing. Anode stimulation of a preset frequency is applied to all electrodes in the stimulation area to render the vibration feeling of the virtual finger sliding across the surface of the virtual object. The vibration frequency of the anode stimulation is f Depends on the virtual hand sliding speed v and the virtual object roughness parameter λ , where the roughness parameter λ It is the average distance between two adjacent wave peaks on the surface of the virtual object. The faster the sliding speed and the smaller the roughness parameter, the higher the frequency of the vibration generated by the sliding of the virtual hand.

[0054] In this embodiment, the anode stimulation frequency in the sliding mode is f Determined as:

[0055] ;

[0056] in f max The maximum value of the microcurrent stimulation vibration frequency that can be perceived by humans is selected as 100 Hz in this embodiment.

[0057] Step S5, when the virtual hand leaves the surface of the virtual object, the stimulation mode is switched to the separation mode. During the process of the virtual hand being separated and lifted from the surface of the virtual object, a gradually decreasing pressure is applied at the center of the stimulation area (e.g., the center of the fingertips of the virtual fingers) according to the degree of separation between the virtual hand and the surface of the virtual object and the softness of the surface of the virtual object, so as to render the trend of stress decreasing during the lifting of the virtual hand. At the same time, a vibration feeling of shrinking the boundary from the outside to the inside is applied to render the deformation process of the virtual hand skin from the outside to the inside during the lifting of the virtual hand.

[0058] In the separation mode, the stress change of the virtual hand is achieved by applying cathode stimulation with varying intensity at the center of the stimulation area, and the skin deformation of the virtual hand is achieved by applying anode stimulation at the boundary of the reduced stimulation area. The stimulation characteristics of the separation mode are related to the softness parameters of the virtual object. The softer the virtual object, the smaller the stress change, that is, the smaller the change in cathode stimulation intensity, and the faster the stimulation area is reduced, that is, the faster the boundary switching of applying anode stimulation.

[0059] Specifically, if Figure 5As shown, when the sliding ends and the virtual hand is detected to be separated from the virtual object, the separation mode is switched. From S51 to S54, as the virtual hand is lifted, the electrodes are gradually deactivated from the outer layer to the inner layer; and because the virtual hand contacts the part where the skin deformation gradually decreases, the stress in the center also gradually decreases. Therefore, a 120Hz anode stimulation is applied to the stimulation electrode located on the gradually shrinking boundary layer to render the boundary of the inward deformation, and a cathode stimulation with reduced intensity is applied to the stimulation electrode located in the boundary layer to render the reduction of pressure. The current amplitude of the cathode stimulation ranges from Ix to Imin. The softer the virtual object, the smaller the stress change, that is, the smaller the change in the cathode stimulation intensity, and the faster the shrinking speed of the stimulation area, that is, the faster the boundary switching of the anode stimulation.

[0060] Step S6: In the virtual scene, the interactor perceives the real surface information of various objects through the three feedback channels of sight, hearing and touch through the friction interaction process including contact, sliding and separation, thus achieving a realistic and immersive interactive experience.

[0061] In this embodiment, the experience of three feedback channels of sight, hearing and touch is designed. Among them, the appearance of the object is reproduced in the virtual scene according to the surface pattern distribution information of the real object, and the visual feedback is provided in real time in the form of a computer display or VR headset during the interaction between the virtual finger and the virtual object; according to the sound information of the friction between the finger and the surface of the real object, the auditory feedback is provided in real time in the form of a speaker during the sliding of the virtual finger and the virtual object; according to the roughness and softness parameter information of the real object and the different friction interaction processes, multi-modal tactile feedback is provided in real time at the finger.

[0062] Example 2

[0063] Based on the same inventive concept, Figure 6 As shown, this embodiment provides a virtual friction tactile rendering device based on micro-current stimulation, comprising:

[0064] The interaction information acquisition module 10 is used to obtain the friction tactile interaction information between the real-world hand and the real object and the hand movement information of the interactor;

[0065] The interactive rendering control module 20 is used to map the acquired friction tactile interaction information and hand motion information to the virtual objects and virtual hands in the virtual scene, and simultaneously render the virtual scene in real time, and monitor the friction interaction state of the virtual hands and virtual objects in the virtual scene, and issue corresponding feedback instructions according to different friction interaction states and interaction parameters;

[0066] The multi-channel interactive feedback module 30 is used to provide three feedback experiences including vision, hearing and touch, wherein the visual feedback is achieved by real-time rendering of a virtual scene in front of the eyes of the interactor, the auditory feedback is achieved by providing corresponding friction sound information in a sliding mode, and the tactile feedback is achieved by applying micro-current stimulation of different modes to the tactile feedback array according to the received feedback instructions to simulate the process of friction interaction.

[0067] Preferably, the tactile feedback array switches to different activation modes according to different friction interaction stages, including contact mode, sliding mode and separation mode, see Example 1 for details.

[0068] Specifically, the virtual friction tactile rendering device based on microcurrent stimulation provided in this embodiment can execute each step of the virtual friction tactile rendering method based on microcurrent stimulation in Embodiment 1 to achieve the same technical effect, which will not be repeated here.

[0069] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A virtual friction tactile rendering method based on microcurrent stimulation, characterized in that: The following steps are involved: S1, obtaining friction tactile interaction information of a real object and hand motion information of an interactor, generating a corresponding virtual object in a virtual scene according to the friction tactile interaction information, and mapping the hand motion information of the interactor to a virtual hand in the virtual scene; S2, defining the friction interaction state between the virtual hand and the surface of the virtual object, wherein the defined friction interaction state includes the virtual hand contacting the surface of the virtual object, the virtual hand sliding on the surface of the virtual object, and the virtual hand leaving the surface of the virtual object; Designing a tactile feedback array, the designed tactile feedback array provides corresponding stimulation modes for different friction interaction states, the stimulation modes including contact mode, sliding mode and separation mode, so as to render the virtual touch in the process of friction interaction between the virtual hand and the surface of the virtual object; S3, real-time detection of the friction interaction state between the virtual hand and the surface of the virtual object. When the virtual hand begins to contact the surface of the virtual object, the stimulation mode is switched to the contact mode. During the contact and pressing process of the virtual hand, the contact position between the virtual hand and the surface of the virtual object is used as the stimulation area according to the relative contact depth between the virtual hand and the surface of the virtual object and the softness of the surface of the virtual object. A gradually increasing pressure sense is applied at the center of the stimulation area to render the trend of increasing stress during the pressing process of the virtual hand. At the same time, a vibration sense that expands the boundary from the inside to the outside is applied to render the deformation process of the virtual hand skin from the inside to the outside during the pressing process of the virtual hand. S4, when the virtual hand starts to slide on the surface of the virtual object, the stimulation mode is switched to the sliding mode, the stimulation area is determined according to the pressing depth during the sliding process, and a vibration feeling with a dynamically changing vibration frequency is given in the stimulation area according to the sliding speed and the roughness of the surface of the virtual object; S5. When the virtual hand leaves the surface of the virtual object, the stimulation mode switches to the separation mode. During the process of the virtual hand separating and lifting from the surface of the virtual object, a gradually decreasing pressure sensation is applied at the center of the stimulation area according to the degree of separation between the virtual hand and the surface of the virtual object and the softness of the surface of the virtual object to render the trend of stress decreasing during the lifting of the virtual hand. At the same time, a vibration sensation that shrinks the boundary from the outside to the inside is applied to render the deformation process of the virtual hand skin from the outside to the inside during the lifting of the virtual hand.

2. The virtual friction tactile rendering method according to claim 1, wherein: The tactile feedback array is a finger multi-layer electrode array, including a ground electrode and a multi-layer stimulation electrode array; the multi-layer stimulation electrode array includes a first layer of stimulation electrodes, a second layer of stimulation electrodes and a third layer of stimulation electrodes; The first layer of stimulation electrodes is located at the center of the fingertip, the second layer of stimulation electrodes is arranged around the first layer of stimulation electrodes, and the third layer of stimulation electrodes is arranged around the second layer of stimulation electrodes.

3. The virtual friction tactile rendering method according to claim 2, wherein: The second layer of stimulation electrodes and the third layer of stimulation electrodes are both distributed in an elliptical shape, with the major axis of the ellipse along the length direction of the finger and the minor axis of the ellipse along the width direction of the finger.

4. The virtual friction tactile rendering method according to claim 2, wherein: For each layer of stimulation electrodes of the multi-layer stimulation electrode array, each layer of stimulation electrodes adopts the same stimulation mode, and different layers of stimulation electrodes adopt different stimulation modes, and the stimulation modes include anode stimulation and cathode stimulation.

5. The virtual friction tactile rendering method according to claim 4, characterized in that: Virtual tactile sensations based on microcurrent stimulation include pressure and vibration. Pressure is achieved through cathode stimulation, while vibration is achieved through anode stimulation. Cathodic stimulation uses negative constant current electrical pulses, and the rendering characteristics of cathodic stimulation are a sense of pressure that spreads around the stimulated area; Anode stimulation uses positive constant current electric pulses, and the rendering characteristics of anode stimulation are a vibration feeling with clear boundaries at the stimulation position.

6. The virtual friction tactile rendering method according to claim 4, characterized in that: In contact mode, the virtual hand pressure stress change is achieved by applying cathode stimulation with varying intensity at the center of the stimulation area, and the virtual hand skin deformation is achieved by applying anode stimulation at the border of the expanded stimulation area; In the sliding mode, anode stimulation is applied to the stimulation area to achieve the vibration feeling of sliding across the surface of the virtual object; In the separation mode, the virtual hand lifting stress variation is achieved by applying cathode stimulation with varying intensity at the center of the stimulation area, and the virtual hand skin deformation is achieved by applying anodal stimulation at the boundary of the reduced stimulation area.

7. The virtual friction tactile rendering method according to claim 6, wherein: The stimulation characteristics of the contact mode are related to the softness parameters of the object. The softer the object, the smaller the stress change, that is, the smaller the change in cathode stimulation intensity, and the faster the expansion speed of the stimulation area, that is, the faster the boundary switching of the anode stimulation; In sliding mode, the vibration frequency of the anodal stimulation f Depends on the virtual hand sliding speed v and the surface roughness parameters of the virtual object λ ; The stimulation characteristics of the separation mode are related to the softness parameters of the virtual object. The softer the virtual object, the smaller the stress change, that is, the smaller the change in cathode stimulation intensity, and the faster the stimulation area shrinks, that is, the faster the boundary switching of applying anode stimulation.

8. The virtual friction tactile rendering method according to claim 7, wherein: Anodal stimulation frequency in sliding mode f for: ； in f max This is the maximum value of the microcurrent stimulation vibration frequency that can be perceived by humans.

9. The virtual friction tactile rendering method according to claim 1, wherein: The virtual friction tactile rendering method further comprises the steps of: S6. In the virtual scene, the interactor perceives the real surface information of various objects through the three feedback channels of sight, hearing and touch through the friction interaction process including contact, sliding and separation, thus achieving a realistic and immersive interactive experience.

10. A virtual friction tactile rendering device based on the method according to any one of claims 1 to 9, characterized in that: include: An interaction information acquisition module is used to obtain the friction tactile interaction information between the real-world hand and the real object and the hand movement information of the interactor; An interactive rendering control module is used to map the acquired friction tactile interaction information and hand motion information to virtual objects and virtual hands in a virtual scene, render the virtual scene in real time, monitor the friction interaction state of the virtual hand and virtual objects in the virtual scene, and issue corresponding feedback instructions according to different friction interaction states and interaction parameters; The multi-channel interactive feedback module is used to provide three feedback experiences including vision, hearing and touch. The visual feedback is achieved by real-time rendering of virtual scenes in front of the eyes of the interactor. The auditory feedback is achieved by providing corresponding friction sound information in sliding mode. The tactile feedback applies micro-current stimulation of different modes to the tactile feedback array according to the received feedback instructions to simulate the process of friction interaction.

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