JP2005043385A - Tactile sensation display and tactile sensation presentation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a tactile sensation display and tactile sensation presentation method capable of stably presenting a variety of tactile feel to the skin. <P>SOLUTION: The tactile sensation display 1 is characterised in that it is provided with a plurality of aperture-like porous parts 3 on the surface of a base 2 to be touched by the human skin 8 and is provided with a plurality of pressure adjusting sections 4 communicatively connected through conduit parts 6 with their respective bottoms. The respective power adjusting sections 4 are controlled by a control section 7 through signal control lines 6. The tactile sensation presentation method is characterised in that the power adjusting sections 4 vary the internal pressure of the porous sections 3 to negative pressure, thereby presenting the tactile feel of the pseudo-pressure sense to the skin 3 on the surface of the base 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tactile display and a tactile providing method, and more particularly to a technique for applying a tactile presentation device in the fields of visually impaired support, medical care, computer interface, virtual reality, amusement, and design support.
[0002]
[Prior art]
Conventionally, various methods have been proposed for tactile presentation that induces tactile sensations by applying artificial deformation to human skin. For example, two-dimensionally arranging a large number of solid actuators such as pin-like stimulating elements and bringing them into direct contact with the skin by their vertical movement (see, for example, Non-Patent Documents 1 and 2) or pistons A technique (for example, refer to Non-Patent Document 3) that presents a tactile sensation by controlling the driving of and the deformation of the rubber film by air injection is known. According to these technologies, it is possible to transmit information for supplementing the audiovisual sense by tactile sense, and it is possible to feel as if it is touching a virtual object.
[0003]
[Non-Patent Document 1]
Kobayashi, Ikei, Fukuda, "Tactile Presentation System in 3D Space", Proceedings of the 4th Annual Conference of the Virtual Reality Society of Japan, 1999, p. 455-458
[Non-Patent Document 2]
M. Shimojo, M. Shinohara, Y. Fukui, “Shape Identification Performance and Pin Matrix Density in a Three Dimensional” Tactile Display (Shape Identification Performance and Pinmatrix Density in a 3 Dimensional Tactile Display) ”, VRAIS '97, 1997, p. 180-187
[Non-Patent Document 3]
Amemiya, Tanaka, Shinohara, “Fingertip-mounted tactile display using air jets”, Proceedings of the 4th Annual Conference of the Virtual Reality Society of Japan, 1999, p. 41-44
[0004]
[Problems to be solved by the invention]
However, in the case of a pin-like stimulation element, it is difficult to keep the contact state between the skin and the stimulation element constant, and there is a problem that stimulation cannot be stably presented. This is because the feeling of stimulation differs between when the hand is strongly pressed against the stimulating element and when the hand is lightly placed. In addition, it is difficult to control the pressure at the moment of contact with respect to contact and non-contact that occur alternately between the skin and the actuator, and there is also a problem that it is difficult to integrate a small actuator.
[0005]
On the other hand, in the case of air injection, there is a problem that the generated airflow has an adverse effect on the tactile sensation and that it is necessary to provide a large capacity compressor. Further, like the pin-like stimulating element, there is a problem that integration is difficult.
[0006]
Although these conventional technologies were able to transmit Braille information, whether or not there was contact with a virtual object, and partial presentation of the elastic nature of the object, there are not always many types of tactile sensations that can be presented. There wasn't.
[0007]
The inventor has made the present invention based on the above recognition, and an object thereof is to realize a tactile display and a tactile providing method capable of stably presenting various tactile sensations on the skin.
[0008]
[Means for Solving the Problems]
One aspect of the present invention is a tactile display. In this tactile display, an opening-like pore portion is provided on the surface of the base to be brought into contact with the skin surface, and a pseudo tactile sensation is generated on the surface of the base by changing the internal pressure of the pore to a negative pressure.
[0009]
Here, “negative pressure” indicates a state in which the pressure such as atmospheric pressure is lower than the surroundings, but this is sufficient to recognize the physical phenomenon that the air in the pores is sucked. According to this aspect, when the air in the pores is sucked, a part of the skin that comes into contact with the substrate surface is sucked, and the sense is recognized as a pseudo pressure sensation. Thereby, a tactile sensation can be stably presented with a simpler configuration.
[0010]
Another aspect of the present invention is also a tactile display. The tactile display includes a base that should be in contact with the skin surface, a pore portion that opens on the base surface, a pressure adjusting portion that changes the internal pressure of the pore portion to a negative pressure, and a conduit portion that communicates the pressure adjusting portion and the pore portion. Have. The pressure adjusting unit generates a pseudo tactile sensation on the surface of the base due to fluctuations in internal pressure.
[0011]
According to this aspect, the internal pressure of the pore portion is controlled to a negative pressure by the pressure adjusting portion through the conduit portion. Since this conduit portion can be formed long, it is easy to downsize and integrate the base separated from the pressure adjusting portion. Further, since no mechanical drive unit is used in the vicinity of the substrate surface, the pressure and the like can be controlled easily and flexibly.
[0012]
Yet another embodiment of the present invention is a tactile sense presentation method. This method generates a pseudo-tactile tactile sensation on the base surface by changing the internal pressure of the pores provided in an opening shape on the base surface to be in contact with the skin surface to a negative pressure.
[0013]
According to this aspect, when the air in the pores is sucked, a part of the skin that comes into contact with the substrate surface is sucked, and the sense is recognized as a pseudo pressure sensation. Thereby, a tactile sensation can be stably presented by a simpler method.
[0014]
In addition, what converted the expression of this invention between the apparatuses, methods, systems, or programs is also effective as an aspect of this invention.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
(Embodiment 1)
In the present embodiment, a tactile presentation method using suction pressure and a tactile display using the method are proposed. Specifically, the skin is brought into close contact with a base having a hole, and a pseudo pressure sensation is presented by sucking air through the hole. In this case, a constant force can be maintained by pressure control, and the contact between the skin and the stimulus presentation surface can be stably maintained by suction. If the tube for sucking air is lengthened and drawn to another place, the tactile display itself can be easily downsized and integrated.
[0016]
FIG. 1 schematically shows a configuration of a tactile display according to Embodiment 1 of the present invention. The tactile display 1 includes a base 2, a plurality of pressure adjusting units 4, a plurality of conduit units 5, a plurality of control signal lines 6, and a control unit 7. The base 2 is a member that contacts the human skin 8. A plurality of pores 3 that are formed in a cylindrical shape and open to the surface of the base 2 are provided inside the base 2. The base 2 including the pores 3 is formed of a member such as a metal or a resin having a hardness that does not easily deform. The interval between the pores 3 is a distance based on a two-point discrimination threshold determined according to the human skin 8 to be contacted. For example, when the finger of the hand is a contact target, the resolution may be about 2 mm. The two-point discrimination area will be described later. The diameters of the opening portions in the plurality of pores 3 are not necessarily uniform.
[0017]
The plurality of conduit portions 5 are tube members that couple the bottom portions of the plurality of pore portions 3 and the plurality of pressure adjusting portions 4 so as to communicate with each other. The plurality of pressure adjusting units 4 are suction pumps that suck the air 9b and change the internal pressures of the plurality of pores 3 to negative pressures. The control unit 7 electrically controls the plurality of pressure regulating units 4 via the plurality of control signal lines 6. 9a is outside air.
[0018]
Assuming that the volume of the pore portion 3 is V and its internal pressure is P, V and P are in a relationship of P × V = constant according to Boyle's law. Accordingly, since the pore 3 itself is not deformed due to a decrease in the internal pressure of the pore 3, a part of the skin 8 that contacts the opening position of the pore 3 is drawn into the pore 3 due to its elasticity. At this time, an edge around the opening portion of the pore portion 3 bites into the skin 8 to induce a pseudo tactile sensation.
[0019]
The control unit 7 generates a drive signal for each of the pressure adjusting units 4 in order to individually control the plurality of pressure adjusting units 4. In this case, the control unit 7 may generate a drive signal so that force is applied to the skin 8 in an arbitrary time pattern, or may generate a drive signal so that the internal pressures of the plurality of pores 3 are different from each other. Good. As described above, various tactile sensations can be presented by independently driving and controlling each pressure adjusting unit 4. The control unit 7 may generate a drive signal for increasing or decreasing the internal pressure while keeping the internal pressure of the pores 3 on the negative pressure side. In this case, the skin 8 can be vibrated.
[0020]
According to the present embodiment, even if the skin 8 is inadvertently moved, the internal pressure of the pore portion 3 is negative, so that no gap is easily generated between the skin 8 and the base 2. In addition, even if a gap is generated, the skin 8 is immediately sucked toward the pore 3 and is in close contact with the surface of the base 2. Thereby, it is possible to continue to provide stimulation stably.
[0021]
(Embodiment 2)
The present embodiment is different from the first embodiment of the present invention in that the hardness around the opening portion of the pore portion 3 can be freely changed by electrical control. FIG. 2 schematically shows a cross section of a tactile display according to Embodiment 2 of the present invention. FIG. 3 is a plan view of the base 2 as viewed from above. On the surface of the base 2, a layer of the variable member 10 is provided around the opening portion of the pore portion 3. The variable member 10 is a magnetorheological fluid.
The control terminal 11 is a coil, and generates a magnetic field to the variable member 10 when a voltage is applied from the control unit 12 via the control signal line 13. The viscosity of the variable member 10 is controlled by a magnetic field applied from the control terminal 11. Even when the internal pressure of the pore portion 3 is constant, the degree to which the skin 8 bites into the edge of the opening portion of the pore portion 3 can be controlled by changing the hardness of the variable member 10. Therefore, the stimulation to the skin 8 can be controlled in more detail.
[0022]
(Embodiment 3)
In the present embodiment, the material of the variable member is different from that of the second embodiment. Other configurations are the same as those of the second embodiment. The variable member 10 in FIGS. 2 and 3 is an electrorheological fluid, and the control terminal 11 is an electrode. The viscosity of the variable member 10 is controlled by the control unit 12 via the control signal line 13 and the control terminal 11. Thereby, even in the case where the internal pressure of the pore portion 3 is made constant as in the second embodiment, the skin 8 bites into the edge of the opening portion of the pore portion 3 by changing the hardness of the variable member 10. The degree can be controlled. Therefore, the stimulation to the skin 8 can be controlled in more detail.
[0023]
(Discussion)
Hereinafter, the principle used to realize the embodiment of the present invention will be considered.
[0024]
1. Stimulation presentation by suction pressure control
By arranging units capable of presenting two-degree-of-freedom stimuli to the palm with a resolution of two-point discrimination threshold, various tactile sensations due to deformation of the skin can be presented. At first glance, it seems that it is necessary to arrange the stimulation units very closely when arranging units at the resolution of the two-point discrimination threshold in the palm. Also, it seems that two degrees of freedom of stimulation are insufficient. However, paying attention to human neurophysiological characteristics, tactile receptor characteristics, arrangement density, etc., it can be estimated that it is sufficient to arrange stimuli with two degrees of freedom at intervals of about 1 cm for the palm.
Regarding such a phenomenon, how pressure is generated will be described based on the analysis result using the finite element method.
[0025]
1.1 Sensation of suction pressure control stimulus
When 10 subjects were given a suction stimulus to bring their palms into contact with different types of holes, the subjects generally had the following sensations.
Large size: Push with the rubber behind the pencil, poke with a glass stir bar
Small size: Needle sticks, pierces with sharpened tip
In addition, there was one subject who felt tingling or tingling, but the remaining subjects had a sensation of something protruding from below. (Strict values such as the size of the hole will be described later. Here, we will qualitatively touch what kind of sensation is generated by the suction stimulus.)
[0026]
1.2 Analysis by finite element method
FIG. 4 shows a fingertip model by the finite element method. Maeno et al. As a paper analyzing the relationship between tactile sensation and skin deformation using the finite element method ("Mechanical relationship between human finger pad structure and tactile receptor position", Transactions of the Japan Society of Mechanical Engineers (C), 63, No. 607, p. 881-888 (1997) is known. Using this as a reference, the following physical property values were used, and the fingertip cross-section was divided into the epidermis, dermis, and subcutaneous tissue layers, and modeled as shown in this figure assuming that the bone and nails were completely constrained.
·Young's modulus
Epidermis 1.36 × 10 ⁵ Pa (1.4 × 10 ^-2 kgf / mm ² )
Dermis 8.0 × 10 ⁴ Pa (8.2 × 10 ^-3 kgf / mm ² )
Subcutaneous tissue 3.4 × 10 ⁴ Pa (3.5 × 10 ^-3 kgf / mm ² )
-Poisson's ratio: 0.48
[0027]
The purpose of this analysis is to elucidate the reason why pressure sensation is presented by suction stimulation by comparing the stress and strain energy distribution when a stimulus of the same size is actually pressed against the stimulus by suction pressure control It is to be.
[0028]
The suction stimulation this time is 10 kPa (1 gf / mm from the result of measuring the pressure actually felt. ² ) With a force of 1.5 mm in width was assumed. On the other hand, the indentation stimulus was similarly analyzed with a stimulus of 1.5 mm in width with a force of 1 gf. Since it is assumed that the skin is brought into contact with the stimulus presentation surface at the time of suction, the contact surface with the base other than the stimulus portion is restricted only in the vertical direction during suction.
[0029]
1.3 Analysis results
Main stress distribution
FIG. 5 is an enlarged view of the contact portion of the main stress distribution. The upper figure shows the case of suction stimulation, and the lower figure shows the case of pushing stimulus. In the case of the suction stimulation shown in the upper diagram, the substantially radial line shown above the opening indicates that stress is generated in the expansion direction. In the case of the pushing stimulus in the lower diagram, the substantially radial line shown above the pushing member indicates the stress in the compression direction. As a result, it can be seen that the direction of the stress is almost opposite between suction and push-in. It can also be seen that in the suction stimulation, the direction of stress is reversed at the boundary between the suction portion and the base portion.
[0030]
Strain energy
FIG. 6 is an enlarged view of the strain energy distribution. The upper figure shows the case of suction stimulation, and the lower figure shows the case of pushing stimulus. In the case of suction stimulation, the strain energy is localized on the surface layer, whereas in the case of indentation stimulation, it can be seen that the strain energy is transmitted to the deep layer. In addition, in the case of suction stimulation, it can also be seen that a portion having a large strain energy value is concentrated on the edge portion of the suction port. Here, when considered together with the fact that the direction of the stress is reversed, it is called a suction stimulus, but in reality, the edge is pushed into the skin by sucking, and the pressure is felt. Show.
[0031]
FIG. 7 shows the strain energy distribution near the receptor. The left figure shows the case of suction stimulation, and the right figure shows the case of pushing stimulation. This figure focuses on the distribution of strain energy in the vicinity of the receptor (see section 2.2) that senses the tactile sensation on the skin surface. From this figure, the suction and indentation stimuli form almost the same distribution. I understand that.
[0032]
The conclusions drawn from the above analysis results are as follows.
1) The edge is pushed into the skin by suction and a pressure sensation is generated.
2) Comparing the strain energy distributions globally, there is a difference that the suction stimulus is localized only on the skin surface and the push stimulus is transmitted to the deep part of the skin. A distribution is formed.
[0033]
The conclusions derived from 1) and 2) above are that tactile receptors are insensitive to stress and sensitive to strain energy. This result was obtained from a study by Nara et al. ("Theory of tactile information processing and its application to tactile displays", Doctoral dissertation at the University of Tokyo, 2000) that focused on the structure of the receptor and analyzed its vibration modes. This is consistent with the findings.
[0034]
1.4 Features of suction pressure display
Consider the advantages of this suction pressure control display.
First, it is possible to present a stable stimulus. This is because suction causes a force to always attract the skin to the stimulus presentation surface.
Next, it is easy to downsize and integrate. This is because the pressure regulating unit (pump) and the base (stimulus presentation unit) can be separated by extending the conduit (tube).
[0035]
2 Tactile spatial resolution
Two items, a two-point discrimination threshold and a mechanoreceptor related to tactile sensation, will be described. Based on these findings, I will explain the hypothesis about the spatial resolution of the sense of touch.
[0036]
2.1 Two-point discrimination threshold
FIG. 8 is a graph showing the two-point discrimination threshold in each part of the human body (Tojo, “Study on resolution of skin tactile sense”, Tokyo University of Agriculture and Technology, Master's thesis, 2002). The measurement of the two-point discrimination threshold is one of the studies on tactile resolution that has been performed for a long time. The two-point discrimination threshold is the minimum distance at which two points can be identified as two points when they are in contact with the skin at the same time. While the two-point discrimination threshold at the fingertip is about 2 mm, it differs greatly depending on the site, such as about 10 mm for the palm and several cm for the back.
[0037]
When a plurality of stimulating elements are arranged on a plane in a tactile display, it is necessary to keep at least the fineness of the two-point discrimination threshold between the stimulating elements. This is because if this interval is coarser than the two-point discrimination threshold, it is impossible to present two points with the minimum interval that can be identified independently by humans. However, even if the pins are two-dimensionally arranged in an array at this interval, it is impossible to present a touch such as cloth or bark. That is, humans can instantly identify features below the two-point discrimination threshold, such as protrusions in the order of several microns, and differences between sharp and round objects. This seemingly contradictory nature has made it difficult to accurately estimate tactile resolution.
[0038]
Therefore, we introduced the idea of freedom of stimulation and tried to resolve the contradiction. In other words, the reason why an arbitrary tactile sensation cannot be presented by the pin array is considered to be “a single degree of freedom of a pin is insufficient.” How much an independent component is necessary for a stimulus having a size below the two-point discrimination threshold is related to the characteristics of mechanoreceptors involved in tactile sensation and their arrangement density.
[0039]
2.2 Mechanoreceptors
FIG. 9 shows the skin structure in the human hairless area (RS Johansson, AB Valbo, “Tactile Sensory Coding in the Gray Brass Skin”). -Of the Human Hand (Tactile Sensitivity Coding in the Glabrous Skin of the Human Hand), TINS, p. 27-32, 1983). There are four types of mechanoreceptors related to the sense of touch. There are four types: Meissner bodies and Merkel cells located relatively close to the surface near the boundary between the epidermis and dermis, and Ruffini terminals and Patini bodies located deep in the skin.
[0040]
FIG. 10 shows the arrangement density of each receptor (RF Schmidt, Yoshinobu Iwamura, et al., “Fundamentals of Sensory Physiology”, Kinyoshido, p. 46, 1986). It can be seen from this figure that the surface receptors are arranged at a high density, while the deep receptors have a large receptive field and a low arrangement density. Considering this point, it is considered that only the two receptors on the surface layer are involved in the characteristic that can distinguish the features below the two-point discrimination threshold mentioned in 2.1. This is because the deep two receptors have a wide receptive field, and it is unlikely that sensitivity is sensitive to fine features below the two-point discrimination threshold.
[0041]
2.3 Hypothesis on spatial resolution
The findings obtained in 2.1 and 2.2 are the following two points.
1) At least two-point discrimination threshold is required to present any tactile sensation
2) Out of the four mechanoreceptors, the two layers on the surface are arranged at a density that is about the two-point discrimination threshold.
[0042]
First, it is assumed that the minimum resolution required for tactile presentation is a two-point discrimination threshold, and that the stimulus presentation units are arranged at that interval. Then, consider how many degrees of freedom need to be presented for each unit. Since the information transmitted by one afferent nerve is replaced by the frequency of nerve firing pulses, it can be seen that the information that can be transmitted for each nerve fiber has a pulse frequency of one degree of freedom. Considering 2) here, it is only the superficial two receptors, the Meissner body and the Merkel cell, that distinguishes stimuli below the two-point discrimination threshold. Information is considered sufficient. The following hypothesis is derived from the above.
[0043]
“Hypothesis”: The tactile sensation perceived by the skin surface layer can be reproduced by presenting a two-degree-of-freedom stimulus that selectively stimulates two surface mechanoreceptors at a resolution of two-point discrimination threshold.
The problem here is what kind of stimulation should be used as a two-degree-of-freedom stimulation that selectively stimulates two mechanoreceptors.
[0044]
Fig. 11 shows the experiment conducted with two types of stimulation, focusing on the curvature of the stimulus, with the plane having the limit of 0 curvature and the point load of curvature ∞ (Tojo, "Research on resolution of skin tactile sense", Tokyo Noko University Master's thesis, 2002).
These two types of stimuli
1) It is possible to discriminate well below the two-point discrimination threshold.
2) Based on the structural features and knowledge of neurophysiological experiments, the Meissner body and the Merkel cell are thought to react selectively by the Meissner body and the Merkel cell by the plane load. .
From the above two points, this two-degree-of-freedom stimulus is considered to be appropriate as a stimulus that satisfies the above hypothesis. The present inventors consider that it is possible to present a stimulus having an intermediate curvature by simultaneously presenting these two-degree-of-freedom stimuli, and conduct a verification experiment thereof. Consider using this two-degree-of-freedom stimulus and presenting an arbitrary curvature with a combination of two-degree-of-freedom stimuli. In addition, S1 used in the figure means a plane stimulus, and S2 means a point load stimulus.
[0045]
2.4 Problems of previous research
In order to verify the above hypothesis, previous experiments have been performed using several stimulus presentation methods. The inventors previously used a presentation method that uses an ultrasonic motor and controls the displacement in the vertical direction by its rotation. The problem with this technique is that the number of revolutions, that is, displacement, can be controlled by the motor. As a result, the feeling is different between when the skin is strongly pressed against the presentation surface and when the skin is lightly placed. In order to solve this problem, a prototype was made using pressure control by a syringe based on the idea that a constant force could be presented by pressure control. This system is a system that can independently control the pressure of two-degree-of-freedom stimulation by making the piston into a double structure. However, friction, air leakage, etc. occur in the piston drive part, and the stimulus cannot be presented stably, and the expected result is not necessarily obtained.
[0046]
As described above, the requirement derived from the problems in the previous research is that “a method capable of presenting a more stable stimulus by pressure control is necessary”. Therefore, considering the tactile sense presentation method and the tactile display proposed by the suction pressure control proposed this time, it is possible to always present a stimulus with a constant force by controlling the pressure. In addition, by sucking air, a force for bringing the skin into close contact with the stimulus presentation surface is generated, and stable stimulation can be presented.
[0047]
3 Experiment
We will describe the results of a psychophysical experiment to verify a hypothesis by making a prototype of a device that presents a stimulus with two degrees of freedom using this stimulation method.
[0048]
3.1 Trial manufacture of stimulus presentation device
Stimulus presentation part shape
As a unit for presenting two-degree-of-freedom stimuli, a stimulus presentation surface having a concentric structure was made using acrylic. FIG. 12 shows a stimulus presentation surface with a concentric structure.
[0049]
First, it is an outer portion presenting a planar stimulus (S1 in FIG. 11). However, if the edge is sharp, that portion is emphasized, and a stimulus having a smooth curvature cannot be obtained. Next, although it is an inner part which presents a point load stimulus (S2 of FIG. 11), it has a shape that two circles are overlapped. This is because the point of contact between the two circles is sharp, the edge is emphasized, and a finer and sharper stimulus can be presented. Each size was determined in consideration of the fact that the two-point discrimination threshold is about 10 mm at the palm.
[0050]
Experimental system
FIG. 13 shows the blocks of the experimental system. This experimental system is mainly composed of three parts. That is, they are a constant pressure source, a pressure conversion holding unit, and a stimulus presentation unit. The constant pressure source on the right side in the figure is always kept at a constant pressure by the pump. However, since the pump is of a type that periodically pulsates and sucks, the container is sandwiched in the latter stage as LPF so as to maintain a constant pressure. Next, the center of the figure is the pressure conversion holding unit. Here, the microvalve is switched on and off every 50 ms to set the pressure in the constant pressure holding container to a desired value. By opening and closing the valve connected to the decompressed container in this way, it is possible to present a stimulus with two degrees of freedom. FIG. 14 shows the appearance of the experimental system. As shown in the figure, the stimulus presentation unit uses a silicon rubber base so that the hand can be brought into contact with the presentation surface stably.
[0051]
3.2 Experimental method
In this experiment, 9 males and 20 females in their 30s and 30s were asked to place their left hand on the stimulus presentation unit, and S1 only, S2 only, and S1 + S2 were randomly presented. After that, a stimulus with a curvature of 0.25 mm, 1.0 mm, and 5.0 mm (the size of the presentation part is 0.5 mm, 2.0 mm, and 5.0 mm, respectively) is actually brought into contact with the right hand, and which is sharper, Or they were compared for the same sharpness. As a result, the sharpness of the suction stimulus is smaller than about 0.25 mm, about 0.25 mm, intermediate between 0.25 mm and 1.0 mm, about 1.0 mm, intermediate between 1.0 mm and 5.0 mm, about 5.0 mm, 5 It can be classified into seven stages of greater than 0.0 mm. Each stimulus was presented at random 5 times to see where the rating corresponds to 7 levels. At the time of this stimulation, the pressure felt well was selected empirically, and the stimulation was performed at that value. Each value is S1 only: -90 kPa, S2 only: -90 kPa, S1 + S2: -60 kPa, -90 kPa.
[0052]
3.3 Results and discussion
FIG. 15 shows the evaluation of 10 people. From this figure, it can be seen that the evaluation of sharpness when S1 and S2 are presented simultaneously is in the middle of the evaluation of S1 and the evaluation of S2, but it is difficult to say that the difference is so clear. However, on the other hand, more than half of the subjects answered that there were three types of questions when they asked the number of types of stimuli after the test.
[0053]
FIG. 16 shows a stimulus presentation by suction pressure control. Stimulation can be presented by bringing the skin into close contact with the base with the holes and sucking air through the holes.
[0054]
FIG. 17 shows the experimental method described in connection with FIG. In this method, since the stimulus presentation surface and the skin are brought into close contact with each other by sucking the skin, it is possible to present the pressure with high reproducibility. Therefore, a stimulus presentation surface as shown in FIG. 17 and FIG. 12 that can present a stimulus with two degrees of freedom was prototyped. In this concentric hole, the case where only the outside is sucked corresponds to S1, and the case where only the inside is sucked corresponds to S2. And it is thought that the intermediate curvature can be shown by sucking both simultaneously.
[0055]
FIG. 18 shows the stress distribution on the skin surface, the strain energy distribution inside the skin, and the actual sensation. FIG. 19 shows an image diagram of a stimulus applied to the skin when two stimuli are combined.
[0056]
The present invention has been described based on some embodiments. These embodiments are exemplifications, and various modifications can be made to combinations of the embodiments, combinations of the respective constituent elements and processing processes, and such modifications are also within the scope of the present invention. Will be understood by those skilled in the art. Hereinafter, modifications will be described.
[0057]
In Embodiment 1 of the present invention, the base including the pores is formed of a member such as a metal or a resin having a hardness that does not easily deform. In the modification, at least the periphery of the opening portion of the pore portion of the base may be formed of an elastic member such as a resin. In that case, when the edge of the opening contacts the human skin, the stimulation more than necessary does not occur, and the stimulation can be suppressed to an appropriate level.
[0058]
In each embodiment of the present invention, the surface of the base is formed as a flat surface. However, in a modification, the surface of the base may be formed as a curved surface. In this case, for example, when the palm part is a contact target, the degree of adhesion between the base and the palm part increases. In addition, the curved surface of the base may be designed with a radius of curvature that is easier to adhere to the palm.
[0059]
【The invention's effect】
According to the present invention, various tactile sensations can be presented.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of a tactile display according to a first embodiment of the present invention.
FIG. 2 is a diagram schematically showing a cross section of a tactile display according to a second embodiment of the present invention.
FIG. 3 is a plan view of the base as viewed from above.
FIG. 4 is a diagram showing a fingertip model by a finite element method.
FIG. 5 is an enlarged view of a contact portion of a main stress distribution.
FIG. 6 is an enlarged view of strain energy distribution.
FIG. 7 is a diagram showing a strain energy distribution in the vicinity of a receptor.
FIG. 8 is a graph showing a two-point discrimination threshold in each part of the human body.
FIG. 9 is a diagram showing a skin structure in a hairless part of a human.
FIG. 10 is a diagram showing the arrangement density of each receptor.
FIG. 11 is a diagram showing an experiment conducted with two types of stimulation, focusing on the curvature of the stimulus, a plane that is the limit of curvature 0 and a point load of curvature ∞.
FIG. 12 is a diagram showing a stimulus presentation surface having a concentric structure.
FIG. 13 is a diagram showing a block of an experimental system.
FIG. 14 is a diagram showing an external appearance of an experimental system.
FIG. 15 is a diagram showing the evaluation of 10 people.
FIG. 16 is a diagram showing stimulus presentation by suction pressure control.
FIG. 17 is a diagram showing the experimental method described in relation to FIG.
FIG. 18 is a diagram showing the stress distribution on the skin surface, the strain energy distribution inside the skin, and the actual sensation.
FIG. 19 is a diagram showing an image of a stimulus applied to the skin when two stimuli are combined.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tactile display, 2 Base | substrate, 3 Pore part, 4 Pressure regulation part, 5 Conduit part, 6 Control signal line, 7 Control part, 8 Skin, 9 Air, 10 Fluctuating member, 11 Control terminal, 12 Control part, 13 Control signal line.

Claims (11)

A tactile display characterized in that an opening-like pore portion is provided on the surface of the base to be in contact with the skin surface, and a pseudo-tactile tactile sensation is generated on the base surface by changing the internal pressure of the pore to a negative pressure. . The tactile display according to claim 1, wherein pressure is increased or decreased while the internal pressure of the pores is maintained at a negative pressure. The tactile display according to claim 1 or 2, wherein a plurality of the pores are provided at a distance interval based on a two-point discrimination threshold of the skin to be contacted. The tactile display according to claim 3, wherein internal pressures of the plurality of pores are individually changed. A base to be in contact with the skin surface;
A pore portion opening in the base surface;
A pressure adjusting unit that varies the internal pressure of the pores to a negative pressure;
A conduit portion communicating the pressure regulating portion and the pore portion,
The tactile display, wherein the pressure adjusting unit generates a pseudo-tactile tactile sensation on the surface of the base due to a change in the internal pressure. The tactile display according to any one of claims 1 to 5, wherein the base has a curved surface to be brought into contact with the skin surface. The tactile display according to claim 1, wherein the base is formed of an elastic member at least around an opening portion of the pore portion. The tactile display according to any one of claims 1 to 7, further comprising a variable member whose surface viscosity is changed by electrical control around an opening position of the pore portion on the base surface. The variable member includes a magnetorheological fluid and a coil that applies a magnetic field to the magnetorheological fluid, and the viscosity of the fluctuating member surface is controlled by the magnetic field applied from the coil. Tactile display as described. The variable member includes an electrorheological fluid and an electrode that applies an electric field to the electrorheological fluid, and the viscosity of the surface of the variable member is controlled by the electric field applied from the electrode. Tactile display as described. A tactile sensation presentation method for generating a pseudo-tactile tactile sensation on the base surface by changing the internal pressure of a pore portion provided in an opening shape on the base surface to be in contact with the skin surface to a negative pressure .

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