JP7720038B2 - tactile sensor - Google Patents

Description

The present invention relates to tactile sensors, and more particularly to optical contact sensors.

Patent Document 1 describes a conventional tactile sensor (an optical tactile sensor in this document). The optical tactile sensor described in Patent Document 1 includes a tactile section with a marker section formed in a convex curved surface, and an imaging means for imaging the rear surface of the tactile section. The imaging means captures an image of the rear surface of the tactile section when an object comes into contact with the tactile section and the tactile section is deformed, thereby converting the behavior of the marker section into image information (image data).

Image information from the marker unit is captured by the control unit. The control unit performs image processing on the acquired image information to measure the coefficient of friction, normal force, tangential force, and torque generated in the tactile unit.

Japanese Patent Application Laid-Open No. 2005-257343

By installing the optical tactile sensor described in Patent Document 1 on a robot hand, feedback control can be performed based on the measured friction coefficient, normal force, tangential force, and torque, allowing the gripping force of the robot hand to be adjusted to an appropriate force. This aims to realize a robot hand with tactile functions as close as possible to those of a human.

However, because humans sense the temperature of an object when grasping it, the amount of information available is insufficient to create a tactile sensor that rivals the human sense of touch.

The present invention was made in consideration of the above circumstances, and aims to provide a tactile sensor that can measure the temperature of a contact object at the same time as measuring mechanical quantities.

One aspect of the tactile sensor according to the present invention comprises a housing, a contact body made of a translucent elastic material including a convex contact surface protruding forward from one side of the housing, with a marker portion formed on the contact surface, and an imaging element disposed within the housing that captures an image of the contact surface through the rear surface of the contact body when an object comes into contact with the contact surface, and the contact body is configured so that when the contact surface comes into contact with the object, the contact surface exhibits a color corresponding to the temperature of the object.

The tactile sensor of the above aspect of the present invention has the advantage of being able to provide a tactile sensor that can measure the temperature of a contact object in addition to measuring a mechanical quantity.

FIG. 1 is a schematic diagram of a tactile sensor according to an embodiment of the present invention. Fig. 2(A) is a perspective view of a contact piece of the tactile sensor, Fig. 2(B) is a plan view of the contact piece, and Fig. 2(C) is a cross-sectional view taken along line X1-X1 of Fig. 2(B). FIG. 3 is a block diagram of the tactile sensor and the control device. Fig. 4A is a diagram showing an image of the contact surface captured by the imaging element, and Fig. 4B is a diagram showing the state when a contact object comes into contact with the contact surface.

<Embodiment>
(1) Overall Configuration The tactile sensor 1 according to this embodiment is an optical tactile sensor 1. The tactile sensor 1 can convert the mechanical quantity that occurs when the sensor comes into contact with an object (sometimes referred to as a "contact object") and the temperature of the object into electrical signals. Therefore, by using the tactile sensor 1 according to this embodiment, it is possible to simultaneously measure the mechanical quantity that occurs when the sensor comes into contact with the object and the temperature of the object.

As used herein, "mechanical quantity" refers to at least one of shear force, normal force, tangential force, coefficient of friction, and torque. The tactile sensor 1 according to this embodiment is capable of measuring all of the following mechanical quantities: shear force, normal force, tangential force, coefficient of friction, and torque. Furthermore, as used herein, "normal force" refers to the force that acts in a direction perpendicular to the contact surface 32 of an object when the tactile sensor 1 is used to press the object. Furthermore, as used herein, "tangential force" refers to the force that acts parallel to the contact surface 32 of the object when the tactile sensor 1 is used to press the object.

The tactile sensor 1 according to this embodiment can measure the temperature of an object at the same time as the mechanical quantities that occur when the object is touched. Therefore, by installing the tactile sensor 1 on the fingers of a robot hand, it can be used appropriately for the following purposes, for example:

For example, it can be used in a robot hand that handles frozen foods. By using the electrical signal from the tactile sensor 1 to perform feedback control, the robot hand is controlled so that it can grip the frozen food with an appropriate force. At the same time, the temperature of the frozen food can be measured while it is being handled. This makes it possible to manage the temperature at a specific time (location) on the production line, and as a result, there is no need to set up a process for measuring the temperature of frozen foods on the production line, thereby shortening the takt time.

The object to be grasped (contact object) by the robot hand is not limited to frozen food, and can be any object that needs to be grasped with an appropriate force and whose temperature needs to be measured. In addition to food, examples of objects to be grasped include industrial products, tableware, textiles, fabric products, and paper products. Furthermore, the tactile sensor 1 is not limited to robot hands; it may also be used in, for example, manufacturing equipment, automobiles, aircraft, and conveyors.

As shown in FIG. 1, the tactile sensor 1 comprises a housing 2, a contact body 3, a half mirror 6, a camera 5 with an image sensor 51, and a light emitter 4. The tactile sensor 1 outputs an electrical signal generated by contact with a contact object to a control device 7. The tactile sensor 1 and control device 7 constitute a sensing system. As described above, the sensing system can be used to control, for example, a robot hand.

(2) Housing The housing 2 is a hollow body that houses a part of the contact body 3, the half mirror 6, the light emitter 4, and the camera 5. In this embodiment, the housing 2 is a rectangular box, but the shape is not particularly limited in the present invention. The housing 2 may be, for example, cylindrical, rectangular, spherical, or the like. When the tactile sensor 1 is installed on a robot hand, the housing 2 may be formed in the shape of a finger.

A contact body 3 is provided on one surface 21 of the housing 2. Here, the direction perpendicular to the surface 21 on which the contact body 3 is provided on the housing 2 is defined as the "front-rear direction," the direction from the surface opposite the surface 21 toward the surface 21 in question in the front-rear direction is defined as the "front direction," and the opposite direction is defined as the "rear direction." Additionally, the direction perpendicular to the front-rear direction and along the longitudinal direction of the housing 2 is defined as the "left-right direction." However, these definitions of directions are provided merely for the convenience of explanation and are not intended to specify the intended use of the tactile sensor 1.

The housing 2 has light-blocking properties and blocks light traveling from the outside of the housing 2 to the inside of the housing 2. There are no particular restrictions on the material of the housing 2, and examples include synthetic resin, metal, wood, paper, carbon, and cloth. The housing 2 in this embodiment is made of black ABS (Acrylonitrile Butadiene Styrene) resin.

The housing 2 in this embodiment houses the contact body 3, half mirror 6, light emitter 4, and camera 5, but does not house the control device 7, although the control device 7 may be disposed inside the housing 2.

(3) Contact Body The contact body 3 is a member of the tactile sensor 1 that has a portion that comes into contact with the contact object. When the contact body 3 comes into contact with the contact object, the portion that comes into contact with the contact object deforms and exhibits a color that corresponds to the temperature of the contact object. As shown in Figure 2(A) , the contact body 3 includes a translucent elastic material 31 that has a contact surface 32, and a presser plate 37 that forms the rear surface of the contact body 3.

The translucent elastic material 31 is an elastic material that allows more than a certain amount of light to pass through, and has a convex contact surface 32 that protrudes forward from one surface 21 of the housing 2. As shown in Figure 2 (A), the translucent elastic material 31 is formed in a hemispherical shape, and therefore the contact surface 32 is composed of a convex curved surface. When a contact object comes into contact with the contact surface 32, the contact surface 32 elastically deforms and assumes a color that corresponds to the temperature of the contact object.

In this embodiment, the translucent elastic material 31 is formed in a hemispherical shape, but the present invention is not limited to this. It may be formed in a cylindrical, prismatic, sheet-like shape, or other shape, as long as it protrudes from one surface 21 of the housing 2. Furthermore, the contact surface 32 is not limited to a spherical surface, and may also be a gently curved surface or a flat surface.

Marker portions 33 are formed on the contact surface 32. The marker portions 33 are marks formed on the contact surface 32. When a contact object comes into contact with the contact surface 32, the marker portions 33 deform in accordance with the deformation of the contact surface 32. Examples of marker portions 33 include a grid pattern, a dot pattern, and a stripe pattern. In this embodiment, a grid pattern (as shown in Figure 2(B)) is used as the marker portion 33.

The marker portion 33 is formed on the contact surface 32 by, for example, forming grooves, ridges, protrusions, depressions, notches, printing, painting, or attaching colored paper. The marker portion 33 may be formed on the contact surface 32 or buried immediately below the contact surface 32. Therefore, in this specification, "the marker portion 33 is formed on the contact surface 32" means that the marker portion 33 is present on the contact surface 32 in such a manner that it deforms in response to deformation of the contact surface 32.

The translucent elastic material 31 is composed of an elastomer (sometimes called a "thermochromic elastomer") containing a matrix material, a light-blocking pigment, and a thermochromic pigment, and exhibits a color that corresponds to the temperature of the object it comes into contact with. The translucent elastic material 31 may be composed of a single layer structure containing a matrix material, a light-blocking pigment, and a thermochromic pigment, but in this embodiment, as shown in Figure 2(C), it is composed of a multilayer structure including a light-blocking layer 34 and a thermochromic layer 35.

Here, if the concentration of the light-blocking pigment in the translucent elastic material 31 is too high, it will be difficult to see the color change in response to the temperature of the object it comes into contact with, while if the concentration of the light-blocking pigment is too low, it will tend to be more susceptible to the color of the object it comes into contact with. If the light-blocking elastic material 31 has a single-layer structure containing a light-blocking pigment and a thermochromic pigment, localized concentration imbalances are likely to occur, but a two-layer structure has the advantage of suppressing localized imbalances in the concentration of the light-blocking pigment.

The light-shielding layer 34 is a layer with a certain degree of light-shielding properties, and when the color of the temperature-indicating layer 35 and the marker portion 33 are captured by the camera 5, it prevents external light from passing through the light-transmitting elastic material 31. This increases the accuracy of image recognition when image processing is performed on the image captured by the camera 5.

The light-blocking layer 34 is formed by mixing a light-blocking pigment into a matrix material. The matrix material is formed from one or more materials selected from silicone rubber, polyurethane resin, and thermoplastic elastomer. Examples of thermoplastic elastomers include styrene-based, polyamide-based, polyester-based, and halogen-based elastomers. Inorganic pigments can be used as the light-blocking pigment. Depending on the color tone, organic pigments may also be mixed in. Examples of inorganic pigments include one or more pigments selected from calcium carbonate, zinc oxide, and titanium oxide. Examples of organic pigments include one or more pigments selected from azo-based and phthalocyanine-based pigments.

The color of the light-shielding layer 34 is the base color of the light-transmitting elastic material 31. It is preferable that the color of the light-shielding layer 34 be set to a color that is distinguishable from the color of the temperature-indicating layer 35. Furthermore, the light-shielding layer 34 of this embodiment is formed with a marker portion 33, but because the light-transmitting elastic material 31 is imaged from the rear, the light-shielding layer 34 needs to have a color that allows the deformation of the marker portion 33 to be distinguished.

The temperature-indicating layer 35 is a layer that changes color according to the temperature of an object that comes into contact with the contact surface 32. The temperature-indicating layer 35 is laminated on the inner side in the thickness direction (the rear side in the front-to-rear direction) of the light-shielding layer 34. The temperature-indicating layer 35 and the light-shielding layer 34 may be formed as separate sheets and then layered on top of each other, or one of the temperature-indicating layer 35 and the light-shielding layer 34 may be formed first and then the other layer may be formed on top of it, or one may be formed and then the other may be coated or painted. Alternatively, the temperature-indicating layer 35 may be coated on one side of a transparent substrate and the light-shielding layer 34 may be coated on the other side and then layered.

The temperature-indicating layer 35 is composed of a matrix material containing a thermochromic pigment component that changes color when exposed to heat. The matrix material is composed of one or more materials selected from silicone rubber, polyurethane resin, and thermoplastic elastomer. The matrix material of the temperature-indicating layer 35 may be the same as the matrix material of the light-shielding layer 34, or it may be composed of a different material.

The thermochromic dye component may be one or more components selected from a microencapsulated pigment containing a leuco dye, vanadium oxide, and bismuth oxide. Among these, a microencapsulated pigment containing a leuco dye is preferred. Examples of leuco dyes include a combination of a lactone ring compound, a color developer, and a desensitizer that melts at the thermosensitive temperature. When the temperature of the thermochromic layer 35 is below a predetermined temperature, the color developer acts as an acid in the microcapsules, opening the lactone ring compound and changing its structure to a carboxylic acid, thereby producing color. Meanwhile, as the temperature of the thermochromic layer 35 increases, the desensitizer melts, causing the base component contained in the desensitizer to bond with the color developer, resulting in ring closure and a return to the lactone ring, causing the color of the thermochromic layer 35 to fade (increasing transparency).

Examples of lactone ring compounds include one or more pigments selected from crystal violet lactone, spirolactones, and the like. Of these, crystal violet lactone is preferred. Examples of color developers include compounds with a phenolic hydroxyl group, such as benzotriazole, monophenols, diphenols, and triphenols. Examples of phlegmizers include higher hydrocarbons, aliphatic higher alcohols, aliphatic higher fatty acids, and aliphatic higher fatty acid esters. Examples of base components contained in phlegmizers include higher fatty acids and quaternary ammonium salts.

As shown in Figure 2(C), the translucent elastic material 31 has a central layer 36 located inside a hemisphere formed by the light-shielding layer 34 and the temperature-indicating layer 35. Examples of the central layer 36 include an elastic material such as silicone rubber, a gel with a certain viscosity, or an air layer. The central layer 36 must be translucent in order to capture an image of the color of the temperature-indicating layer 35 and the marker portion 33. In this case, transparency is preferred.

The translucent elastic material 31 deforms when it comes into contact with an object, and elastically returns to its original shape when the object is released. For this reason, it is preferable that the material have the following physical properties:

The elongation at break in accordance with JIS K 6251 is preferably 200% or more, and more preferably 300% or more. If the elongation at break is less than 200%, the fatigue durability required for the tactile sensor 1 may not be achieved.

The tensile strength in accordance with JIS K 6251 is preferably 6.0 MPa or more, and more preferably 8.0 MPa or more. If the tensile strength is less than 6.0 MPa, the strength required for the tactile sensor 1 may not be achieved.

The durometer hardness (Type A) according to JIS K 6253-2 is preferably A20 or more and A60 or less, and more preferably A30 or more and A50 or less. If the durometer hardness is less than A20 or more than A60, the flexibility required for the tactile sensor 1 may not be achieved.

The retaining plate 37 is attached to the rear surface of the translucent elastic material 31 and forms the rear surface of the contact body 3. The retaining plate 37 is harder than the translucent elastic material 31. The translucent elastic material 31 is attached to the retaining plate 37 by, for example, adhesive bonding, crimping, welding, etc. The retaining plate 37 is made of a transparent plate. Examples of the retaining plate 37 include an acrylic plate, a glass plate, and a polycarbonate plate. By fixing the retaining plate 37 to the housing 2, the contact body 3 is attached to the housing 2 so that the contact surface 32 protrudes from one surface 21 of the housing 2.

(4) Light-Emitting Body The light-emitting body 4 is disposed inside the housing 2 and emits light to illuminate the inside of the housing 2. The light emitted from the light-emitting body 4 allows the camera 5 to capture images of the color of the thermosensitive layer 35 of the contact body 3 and the manner in which the marker portion 33 changes.

The light emitter 4 is, for example, a white LED lamp, but is not limited to an LED lamp. In this embodiment, the light emitter 4 is arranged along the rear surface of the housing 2, but its position can be changed as appropriate depending on the brightness of the area where light is required.

The light emitter 4 in this embodiment is formed in a flat plate shape, but it may also be rod-shaped or ring-shaped, for example.

(5) Camera The camera 5 has an imaging element 51. The imaging element 51 images the contact surface 32 through the rear surface of the contact body 3. By imaging the contact surface 32 when an object comes into contact with the contact surface 32, the color of the translucent elastic material 31 and the state of the marker portion 33 can be imaged and converted into an electrical signal. Examples of the imaging element 51 include a CMOS (Complementary Metal Oxide Semiconductor) and a CCD (Charge Coupled Device).

The camera 5 is disposed within the housing 2. The camera 5 is disposed on the contact body 3, behind the contact surface 32. The camera 5 captures the behavior (displacement, distortion) of the marker portion 33 when a contact object comes into contact with the contact body 3, so the focus of the camera 5 is on the marker portion 33.

As shown in Figure 1, the camera 5 captures an image of the contact surface 32 via the half mirror 6. The camera 5 is positioned so that the optical axis L1 between the camera 5 and the half mirror 6 and the optical axis L2 between the half mirror 6 and the contact body 3 are perpendicular to each other. However, in the present invention, the camera 5 may also be positioned behind the contact body 3 so that the optical axis is linear.

(6) Control Device The control device 7 has a control unit that receives an electrical signal from the imaging element 51 and controls an object to be controlled, such as a robot hand. As shown in Fig. 3, the control device 7 includes a CPU 71, a ROM 72, a RAM 73, and an input/output port 74. The ROM 72, the RAM 73, and the input/output port 74 are connected to the CPU 71.

The CPU 71 executes various processes to control the entire sensing system and outputs the results of these processes as control signals. The ROM 72 stores control programs for controlling the sensing system. The RAM 73 temporarily stores various information necessary for the operation of the sensing system. The input/output port 74 is connected to the camera 5 and light emitter 4.

An electrical signal generated by capturing an image of the behavior of the marker unit 33 and the color of the contact surface 32 using the imaging element 51 is input to the CPU 71 via the input/output port 74. This electrical signal includes image data. The CPU 71 outputs an electrical signal to the light emitter 4 via the input/output port 74 to light the light emitter 4.

Image data captured at regular intervals (e.g., every 33 ms) is input to the CPU 71. When image data for the marker portion 33 of the contact body 3 before deformation is input to the CPU 71, the CPU 71 performs image processing and recognizes the pattern of the reference marker portion 33. Here, as shown in Figure 4(A), the CPU 71 recognizes the marker portion 33 as a grid-like pattern.

Image data acquired at regular intervals is stored in a memory area of RAM 73 for a set period of time, with the oldest data being deleted sequentially. There are no particular restrictions on the software used to perform image processing; for example, HALCON (manufactured by MVTec) is used.

When a contact object comes into contact with the contact surface 32 of the contact body 3 and the contact surface 32 is deformed, image data of the deformed surface is input to the CPU 71. The CPU 71 determines the contact area T1 from the input image data of the deformed surface, and within the contact area T1, determines the stuck area T11 and the slipping area T12 (see Figure 4 (B)).

The "contact area T1" here refers to the area of the contact surface 32 that is in contact with the contact object. In an image ( FIG. 4(B) ) captured by the image sensor 51 of the state in which the contact object is in contact with the contact surface 32, the marker portion 33 is recognized as a grid-like pattern, and the area in contact with the contact object appears to have a different brightness than the non-contact area (specifically, the contact area is brighter than the non-contact area). Therefore, the CPU 71 can extract the contact area T1 from the marker portion 33 of the image data. Moreover, in the tactile sensor 1 according to this embodiment, the light-emitting body 4 emits white light, so the difference in brightness between the contact area T1 and the non-contact area T1 is clearly visible. This allows the CPU 71 to more accurately determine the contact area T1. In particular, in this embodiment, the contact body 3 exhibits a color that corresponds to the temperature of the contact object, so the temperature of the area in contact with the contact object changes. This improves the accuracy of extracting the contact area T1.

The "fixed region T11" refers to the region of the image data where the marker part 33 does not move when a contact object is in contact with the contact surface 32. The "slip region T12" refers to the region where the marker part 33 can move when a contact object is in contact with the contact surface 32.

Once the CPU 71 determines the contact area T1, adhesion area T11, and slippage area T12, it can calculate the shear force, normal force, tangential force, friction coefficient, and torque. Specific methods for calculating these mechanical quantities can use known techniques (for example, those described in JP 2005-257343 A), so a detailed description will be omitted here.

The CPU 71 can determine the temperature of the contact object from the color of the contact surface 32 in the image data. The CPU 71 extracts RGB values from the color of the contact surface 32. The ROM 72 stores the RGB values in association with the temperature of the contact object. The CPU 71 can reference the RGB values and read the temperature of the contact object from the ROM 72.

The control device 7 calculates the shear force, normal force, tangential force, friction coefficient, torque, and temperature of the contact object, and based on this, can output a control signal for controlling an actuator (e.g., a robot hand) not shown.

<Modification>
The above embodiment is merely one of various embodiments of the present invention. The embodiment can be modified in various ways depending on the design, etc., as long as the object of the present invention can be achieved. Modifications of the embodiment are listed below. The modifications described below can be applied in appropriate combinations.

In the tactile sensor 1 according to the above embodiment, the rear surface of the contact body 3 is formed by a retaining plate 37, but in the present invention, the retaining plate 37 may be omitted.

In the contact sensor according to the above embodiment, the contact surface 32 is configured as a convex curved surface, but even if the contact surface 32 is flat, it is still possible to measure at least shear force. Therefore, the contact sensor according to the present invention only needs to be able to measure at least one of the following mechanical quantities: shear force, normal force, tangential force, coefficient of friction, and torque.

The contact sensor in the above embodiment has a half mirror 6, but in the present invention, the half mirror 6 does not have to be provided. Furthermore, the half mirror 6 may also be a mirror.

In the contact sensor according to the above embodiment, the surface 21 of the housing 2 from which the contact surface 32 of the contact body 3 protrudes is flat, but the surface 21 may be curved or may not be flat.

In the above embodiment, the contact body 3 has a laminated temperature-indicating layer 35 and a light-blocking layer 34. However, in the present invention, a single matrix material may contain both a temperature-indicating pigment and a light-blocking pigment.

<Summary>
As described above, the tactile sensor 1 according to the first aspect includes the housing 2, the contactor 3 having a light-transmitting elastic material 31 including a convex contact surface 32 that protrudes forward from one surface 21 of the housing 2 and on which a marker portion 33 is formed, and the imaging element 51 that is disposed within the housing 2 and that captures an image of the contact surface 32 through the rear surface of the contactor 3 when an object comes into contact with the contact surface 32. The contactor 3 is configured so that when the contact surface 32 comes into contact with an object, the contact surface 32 exhibits a color that corresponds to the temperature of the object.

This aspect provides a tactile sensor 1 that can simultaneously measure the mechanical quantity generated when contacting an object and the temperature of the object.

In the tactile sensor 1 according to the second aspect, the contact surface 32 is a convex curved surface that protrudes forward in the first aspect.

This aspect provides a sensor that can measure the temperature of an object as well as the shear force, normal force, tangential force, friction coefficient, and torque that occur when coming into contact with the object.

In the tactile sensor 1 according to the third aspect, in the first or second aspect, the light-transmitting elastic material 31 has a light-shielding layer 34 containing a light-shielding pigment in a matrix material, and a thermochromic layer 35 laminated on the light-shielding layer 34 and containing a thermochromic pigment in a matrix material.

This embodiment can suppress localized variations in the concentration of the light-blocking pigment. As a result, when an object is contacted, the color change of the light-transmitting elastic material 31 can be easily recognized through image processing, improving the accuracy of the object temperature measured by the tactile sensor 1.

In the tactile sensor 1 of the fourth aspect, the light-blocking pigment is an inorganic pigment or a mixture of an inorganic pigment and an organic pigment. The inorganic pigment is one or more pigments selected from calcium carbonate, zinc oxide, and titanium oxide, and the organic pigment is one or more pigments selected from azo pigments and phthalocyanine pigments.

According to this aspect, the tactile sensor 1 can be made to output a signal that allows the color of the thermometric layer 35 to be appropriately recognized through image processing.

In the tactile sensor 1 according to the fifth aspect, in the third or fourth aspect, the thermochromic pigment is one or more pigments selected from a microencapsulated pigment containing a leuco dye, vanadium oxide, and bismuth oxide.

In this embodiment, the thermosensitive layer 35 can change color appropriately depending on the temperature of the object, allowing the tactile sensor 1 to output a signal that allows the color of the thermosensitive layer 35 to be appropriately recognized through image processing.

In the tactile sensor 1 according to the sixth aspect, in any one of the third to fifth aspects, the matrix material is one or more materials selected from silicone rubber, polyurethane resin, and thermoplastic elastomer.

This aspect allows for the construction of a contact body 3 that is capable of appropriate elastic deformation when measuring mechanical quantities.

In the tactile sensor 1 according to the seventh aspect, in any one of the first to sixth aspects, the elongation at break of the translucent elastic material 31 is 200% or more.

This aspect makes it possible to provide a tactile sensor 1 that has a contact body 3 that can withstand deformation while exhibiting a color that corresponds to the temperature of an object when it comes into contact with the object.

In the tactile sensor 1 according to the eighth aspect, in any one of the first to seventh aspects, the tensile strength of the translucent elastic material 31 is 6.0 MPa or more.

This embodiment makes it possible to provide a tactile sensor 1 that has a contact body 3 that can withstand deformation while exhibiting a color that corresponds to the temperature of an object.

In the tactile sensor 1 according to the ninth aspect, in any one of the first to eighth aspects, the durometer hardness of the translucent elastic material 31 is A20 or more and A60 or less.

This embodiment makes it possible to provide a tactile sensor 1 that has a contact body 3 that can withstand deformation while exhibiting a color that corresponds to the temperature of an object.

REFERENCE SIGNS LIST 1 tactile sensor 2 housing 21 one surface 3 contact body 31 light-transmitting elastic material 32 contact surface 33 marker portion 34 light-shielding layer 35 temperature-indicating layer 51 imaging element

Claims (7)

The housing and
a contact body having a light-transmitting elastic material including a convex contact surface protruding forward from one surface of the housing, the contact body having a marker portion formed on the contact surface;
an imaging element disposed within the housing, which captures an image of the contact surface through a rear surface of the contact body when an object comes into contact with the contact surface;
Equipped with
the contact body is configured so that when the contact surface comes into contact with the object, the contact surface exhibits a color corresponding to a temperature of the object;
The translucent elastic material is
a light-shielding layer containing a light-shielding pigment in a matrix material;
a thermochromic layer laminated on the light-shielding layer and containing a thermochromic pigment in a matrix material;
having
Tactile sensor. The contact surface is a convex curved surface that protrudes forward.
The tactile sensor according to claim 1 . the thermochromic pigment is one or more pigments selected from the group consisting of a microencapsulated pigment containing a leuco dye, vanadium oxide, and bismuth oxide;
The tactile sensor according to claim 1 . the matrix material is one or more materials selected from silicone rubber, polyurethane resin, and thermoplastic elastomer;
The tactile sensor according to claim 1 or 3 . The translucent elastic material has an elongation at break of 200% or more.
The tactile sensor according to any one of claims 1 to 4 . The tensile strength of the translucent elastic material is 6.0 MPa or more.
The tactile sensor according to any one of claims 1 to 5 . The durometer hardness of the translucent elastic material is A20 or more and A60 or less.
The tactile sensor according to any one of claims 1 to 6 .