JP2013232293A - Tactile sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tactile sensor having excellent sensitivity by suppressing deterioration.SOLUTION: A pair of electrodes 2, 2 are attached to a magnetic rubber body 1 obtained by hardening a mixture of a magnetic mixed fluid containing a magnetic fluid and Ni and a rubber component in the presence of a magnetic field, and the magnetic rubber body 1 is coated with a resin body 3. Preferably, the resin body 3 is formed of a silicon resin. Preferably, irregularities 5 are formed on the surface of the resin body 3. Preferably, the magnetic rubber body 1 is sealed with a resin wrap film 4 in the resin body 3.

Description

  The present invention relates to a tactile sensor that detects stress with high sensitivity.

  Conductive rubber obtained by dispersing conductive powder in a rubber material that is an insulator has an insulating property when not pressurized, but is a so-called pressure-sensitive conductive material that becomes conductive when pressure is applied. It is widely used as a switch and sensor for electrical and electronic equipment. In the field of robot technology that has made rapid progress, it is also attracting attention as a material having a haptic function such as artificial skin.

  For example, Patent Document 1 discloses a pressure-sensitive conductive rubber mainly composed of natural or synthetic rubber, conductive carbon, insulating mica flakes, a blooming agent such as fats and oils, and a surface drying agent. The pressure-sensitive conductivity is improved by increasing the difference between the electric resistance values when no pressure is applied and when the pressure is applied. In Patent Document 2, the average composition is represented by AgxM1-x (where M is one or more metals selected from Ni, Co, Cu, and Fe, 0.001 ≦ x ≦ 0.4), A conductive rubber containing an alloy powder whose silver concentration increases toward the inside and a binder having rubber elasticity is disclosed.

JP-A-1-193342 JP-A-5-81924 International Publication WO2008 / 111194

  Up to now, the present applicant has demanded not only durability and electrical conductivity, but also improvement of thermal characteristics such as thermal conductivity in applications where haptic functions as described above are required. From a viewpoint, the electroconductive composite material as shown to patent document 3 is proposed.

  Here, the rubber material used for the conductive rubber is easily deteriorated, and when the rubber material is deteriorated, the sensitivity as a tactile sensor is lowered. Therefore, it is required to suppress the deterioration of the rubber material. There is also a need for further improvement in sensitivity of the tactile sensor.

  An object of the present invention is to provide a tactile sensor that suppresses deterioration and has excellent sensitivity.

  In the tactile sensor according to the present invention, a pair of electrodes is attached to a magnetic rubber body obtained by curing a mixture containing a magnetic fluid and a magnetic mixed fluid containing Ni and a rubber component in the presence of a magnetic field, and the magnetic sensor The rubber body is covered with a resin body.

  The resin body is preferably formed of a silicone resin.

  It is preferable that irregularities are formed on the surface of the resin body. In that case, the unevenness of the resin body is preferably an uneven pattern of any one of a concentric pattern, a pattern in which a plurality of straight lines are arranged in parallel, and a lattice pattern.

  The magnetic rubber body is preferably sealed with a resinous wrap film inside the resin body. In that case, the wrap film is preferably a film formed of polyvinylidene chloride.

  The magnetic fluid mixture preferably contains Cu.

  The rubber component is preferably a rubber material for balloons.

  The tactile sensor is preferably in the form of a sheet.

  It is preferable that the tactile sensor detects any one or more selected from contact of an object, contact force, surface roughness, and softness.

  According to the present invention, it is possible to obtain an ultra-sensitive tactile sensor in which deterioration is suppressed.

An example of an embodiment of a tactile sensor is shown, (a) is an exploded perspective view, (b) is a plan view, (c) is a perspective view, and (d) is an example of an internal structure (magnetic rubber body). It is a top view. (A) and (b) show an example of the internal structure (magnetic rubber body) of the tactile sensor, (c) and (d) show another example of the internal structure (magnetic rubber body) of the touch sensor, (e ) And (f) show still another example of the internal structure (magnetic rubber body) of the tactile sensor, (a), (c) and (e) are plan views, and (b), (d) and (f). Is a front view. An example of the measurement by a tactile sensor is shown, (a) is a perspective view, (b) is a sectional view. An example of embodiment of a tactile sensor is shown, (a) is sectional drawing, (b) is an expanded sectional view. (A)-(c) is a top view which shows an example of an uneven | corrugated pattern. It is sectional drawing which shows an example of manufacture of a magnetic rubber body. It is sectional drawing which shows an example of manufacture of a resin body. An example of embodiment of a tactile sensor is shown, (a) is a disassembled perspective view, (b) is sectional drawing. It is a graph which shows the measurement result by a magnetic rubber body. It is a photograph explaining an example of a magnetic rubber body. It is the partially broken front view which shows an example of the experimental apparatus using a tactile sensor. It is a photograph which shows an example of a to-be-inspected object (an acrylic board and sandpaper). It is a graph which shows the electric current change of experiment using a magnetic rubber body (rubber for balloons). It is a graph which shows the electric current change of the experiment using pressure-sensitive conductive rubber. It is a photograph which shows an example of a tactile sensor. (A) And (b) is a photograph which shows an example of a tactile sensor. It is a graph which shows the relationship between surface roughness and electric current amount. It is a graph which shows the relationship between surface roughness and electric current amount. It is a graph which shows the relationship between surface roughness and electric current amount. It is a graph which shows the relationship between surface roughness and electric current amount. It is a graph which shows the relationship between surface roughness and electric current amount. It is a graph which shows the relationship between surface roughness and electric current amount.

  In the tactile sensor of the present invention, a magnetic rubber body whose electrical conductivity changes when a force is applied is used. The magnetic rubber body is obtained by curing a mixture containing a magnetic fluid containing magnetic fluid and Ni and a rubber component in the presence of a magnetic field. The magnetic fluid mixture preferably contains Cu. Hereinafter, the magnetic fluid may be referred to as MF (Magnetic Fluid), the magnetic mixed fluid may be referred to as MCF (Magnetic Compound Fluid), and the magnetic rubber body may be referred to as a tactile sensor rubber or MCF rubber.

  The magnetic rubber body is preferably obtained by curing a mixture of a magnetic mixed fluid obtained by dispersing Ni powder in a magnetic fluid and a natural rubber material for balloons in the presence of a magnetic field. When Cu is contained, the magnetic rubber body preferably cures a mixture of a magnetic mixed fluid obtained by dispersing Ni powder and Cu powder in a magnetic fluid and a natural rubber material for balloons in the presence of a magnetic field. Obtained by.

  The reason why Ni is used in the magnetic rubber body is that Ni is more ferromagnetic than Fe or the like. The reason why it is preferable to use both Ni and Cu is that Ni has higher ferromagnetism than Fe, etc., and in order to enhance both heat and electricity conductivity, the combined use of Cu This is because is effective. Further, as will be described later, by curing in the presence of a magnetic field, a cluster having a unique structure formed by aggregation of Ni and Cu inside the conductive composite material is obtained.

  In order to obtain a magnetic mixed fluid, it is preferable to add Ni powder as Ni to the magnetic fluid. As the Ni powder, it is particularly preferable to use granular Ni powder, complex Ni-shaped particles having a plurality of convex portions on the surface, or elongated or rod-shaped Ni powder having an average length of 3 to 7 μm. preferable. Such Ni powder can be produced by an atomizing method.

  In order to obtain a magnetic mixed fluid, it is preferable to add Cu powder as Cu to the magnetic fluid. As the Cu powder, it is particularly preferable to use an elongated, rod-like or dendritic Cu powder (for example, an average length of 8 to 10 μm). Such Cu powder can be produced by an electrolytic method.

As a magnetic fluid (MF) for obtaining a magnetic mixed fluid, a water-based magnetic fluid is preferably used. This is because when the rubber material for balloons is used, the rubber material for balloons and water are compatible. For example, a magnetic fluid in which spherical magnetite particles (Fe ₃ O ₄ ) of about 10 nm are dispersed in a water-based medium can be used. Further, a kerosene-based magnetic fluid may be used, or an alkylnaphthalene-based magnetic fluid may be used. The magnetic fluid is composed of magnetite particles and a base liquid. The magnetite aggregates with Ni powder or Cu powder to form a cluster, but the base liquid is trapped between rubber polymers that are elastic polymer materials. It is thought that. The base liquid may be composed of only a liquid agent (for example, water), or may be a liquid in which a polymer is dissolved.

  The magnetic mixed fluid (MCF) can be obtained by mixing Ni powder, Cu powder and magnetic fluid (MF) in a predetermined blending amount. The blending amount can be appropriately determined based on the required conductivity, elasticity, elasticity, thermal conductivity, etc., but preferably the Ni content is 5 to 90 mass with respect to the total mass of the magnetic fluid mixture. %, And the content of the magnetic fluid is preferably in the range of 1 to 40% by mass. Moreover, when it contains Cu, it is preferable that content of Cu is the range of 5-40 mass%. In addition, 0 mass% may be sufficient as content of Cu. The mass ratio of Ni and Cu can be, for example, 1: 5 to 5: 1.

  As the rubber component used for the magnetic rubber body, it is preferable to use a rubber material for balloons. By using a balloon rubber material, an elastic magnetic rubber body can be obtained. The balloon rubber material may be a synthetic rubber material, but is preferably a natural rubber material. The natural rubber material is an elastic polymer material and is used for balloons. By using a natural rubber material for balloons, excellent elasticity and extensibility can be imparted to the cured product. Hereinafter, the natural rubber material for balloons is sometimes referred to as balloon natural rubber.

  As a natural rubber material for balloons, latex obtained from a rubber tree can be used. As latex, modeling latex is particularly preferable. The latex may be a non-vulcanized natural rubber latex or a vulcanized natural rubber latex (natural rubber latex containing sulfur as a vulcanizing agent).

  The latex is preferably an ultra-low ammonia natural rubber latex that hardly gives an ammonia odor. When ammonia is mixed in a natural rubber latex that is generally used, 0.7 to 0.25% by mass of ammonia is contained. Such products are mainly used in the rubber industry to produce rubber gloves, rubber balloons, condoms, foam rubber products and the like. In recent years, there has been a growing demand to change organic solvent-based adhesives, pressure-sensitive adhesives, and paints to water-based due to VOC problems and environmental problems. In addition, natural rubber is highly appreciated as a biomass material, and the modification technology of natural rubber is also progressing. Therefore, utilization for applications that have not been considered so far has been studied. For example, it can be used for building material adhesives, paper adhesives, coating agents, fiber adhesives, and the like. When considered in their new applications, natural rubber latex has often been rejected due to the pungent ammonia odor. Therefore, a low ammonia natural rubber having an ammonia concentration of, for example, less than 0.25% by mass is preferable. Specifically, for example, NR-LATEX (manufactured by Hiratek) can be used as the natural rubber for the magnetic rubber body.

  Silicone rubber (silicone oil rubber) can also be used as the rubber component of the magnetic rubber body. The silicone rubber may be the same as that used for the resin body covering the magnetic rubber body. Synthetic rubber can also be used as the rubber component of the magnetic rubber body. As the synthetic rubber, polybutadiene rubber, nitrile rubber, chloroprene rubber and the like can be used. These rubbers are obtained by addition polymerization or copolymerization. Specifically, acrylic rubber, nitrile rubber, isoprene rubber, urethane rubber, ethylene propylene rubber, chlorosulfonated polyethylene, epichlorohydrin rubber, chloroprene rubber, silicone rubber, styrene-butadiene rubber, butadiene rubber, fluorine rubber, polyisobutylene (butyl rubber) ) Etc. can be used. These rubbers can be used alone or in combination. Synthetic rubber and natural rubber may be mixed. However, natural rubber for balloons is preferable to silicone rubber and synthetic rubber.

  The rubber component is a main component for allowing the magnetic rubber body to exist as a solid rubber. The content of the rubber component is preferably 30 to 90% by mass and more preferably 45 to 70% by mass with respect to the total mass of the magnetic rubber body. The content of the magnetic fluid mixture in the magnetic rubber body is preferably 10 to 70% by mass, more preferably 30 to 50% by mass.

  It is particularly important that the mixture of magnetic mixed fluid (MCF) and rubber component be cured in the presence of a magnetic field. By applying a magnetic field, Cu powder and Ni powder are aggregated to form a plurality of primary clusters each having a dendritic form, and these primary clusters come into contact with each other to form a massive network cluster. (Secondary cluster) is formed in the conductive composite material so as to have orientation in the direction of application of the magnetic field. In addition, since the plurality of primary clusters distributed in the conductive composite material are not connected to each other, the conductive composite material expands and contracts due to the elastic characteristics of the rubber component, so that the primary clusters contact each other. It is considered possible that the portions that are in contact with each other shift and come into contact with another primary cluster. Such a cluster structure can be visually confirmed.

  The mechanism for forming such clusters is currently under investigation, but so far, due to the remanent magnetization of Ni, the action of attracting Ni particles and magnetite particles in magnetic fluid by magnetic force, copper The powder dendritic structure acts as a site where net-like or network-like clusters are likely to be formed, or magnetism tends to concentrate on the convex portions of the non-spherical Ni particle surface, which contributes to the formation of network-like clusters, etc. It is considered promising. Further, such network-like clusters are not randomly distributed in the conductive composite material, but are distributed with an appropriate degree of orientation in the direction in which the magnetic field is applied.

  Here, the specific example of the preferable composition of the mixture which obtains a magnetic rubber body is shown. It has been confirmed that magnetic rubber bodies obtained from these mixtures can be used as tactile sensors.

(Composition Example 1)
Natural rubber (NR-LATEX): 80g (51.6wt%)
Ni: 40 g (25.8 wt%)
Cu: 20 g (12.9 wt%)
Magnetic fluid: 15 g (water: 6.3 wt%, magnetite: 3.4 wt%)
(Composition example 2)
Natural rubber (NR-LATEX): 40 g (51.9 wt%)
Ni: 30 g (38.9 wt%)
Magnetic fluid: 7 g (water: 6 wt%, magnetite: 3.2 wt%)
* In Composition Examples 1 and 2, magnetite is a spherical particle having a diameter of 10 nm made of Fe ₃ O ₄ . Moreover, what mixed water and magnetite becomes the quantity of magnetic fluid (MF). Further, the amount of magnetic mixed fluid (MCF) is 48.4 wt% in Composition Example 1 and 48.1 wt% in Composition Example 2.

  FIG. 1 shows an example of an embodiment of the tactile sensor A. FIG. 1A illustrates a state in which the tactile sensor A is disassembled or a state in which the tactile sensor A is assembled. FIGS. 1B and 1C show the overall state of the tactile sensor A. FIG. FIG. 1D shows the internal structure of the tactile sensor A and shows the magnetic rubber body 1 to which the electrode 2 is attached. The tactile sensor A has a pair of electrodes 2 and 2 attached to a magnetic rubber body 1 obtained by curing a mixture containing a magnetic fluid and a magnetic mixed fluid containing Ni and a rubber component in the presence of a magnetic field. A rubber body 1 is covered with a resin body 3.

  If the magnetic rubber body 1 is kept in contact with air, it may be deteriorated by being oxidized by moisture or oxygen. Therefore, the entire magnetic rubber body 1 is covered with the resin body 3. Thereby, it can suppress that the magnetic rubber body 1 deteriorates. Further, in the tactile sensor A, the electrode 2 is attached to the magnetic rubber body 1, but if the electrode 2 is exposed, it is easily damaged or damaged. However, by covering the magnetic rubber body 1 with the resin body 3, the electrode 2 can be disposed so as not to be exposed on the surface, thereby preventing the electrode 2 from being broken or damaged. be able to.

  The resin body 3 is preferably insulative. Moreover, it is preferable that the resin body 3 has flexibility. By having flexibility, the resin body 3 is deformed when an object comes into contact with the resin body 3, and the deformation is transmitted to the surface of the magnetic rubber body 1 to detect a current change in the magnetic rubber body 1. it can.

  The resin body 3 is preferably formed of a silicone resin. When the resin body 3 is composed of a silicone resin, a change in the contact of the object can be satisfactorily transmitted to the magnetic rubber body 1 by deformation of the silicone resin body. Specifically, the resin body 3 can be composed of silicone oil rubber.

  The resin body 3 formed of a silicone resin can be formed by curing a silicone resin composition containing silicone oil as a main component. The silicone resin composition is a liquid composition containing a silicone oil, a curing agent, and, if necessary, a solvent. A solvent may or may not be contained.

  As the silicone oil, a low-viscosity silicone resin or a silicone monomer that forms a silicone one-component RTV rubber or a silicone two-component RTV rubber can be used. For example, KE series silicone manufactured by Shin-Etsu Chemical Co., Ltd. can be used. Further, polyorganosiloxane may be the main component. The RTV rubber is room temperature curable rubber.

  As a hardening | curing agent, what is suitable for hardening a silicone oil can be used suitably. For example, it may be an acid.

  A thinner can be used as the solvent. The hardness of the resin body 3 can be adjusted by using a solvent. As the thinner, for example, aromatic hydrocarbons, acetate esters, alcohols and the like can be used. Specifically, toluene, xylene, methanol, ethyl acetate, methyl ethyl ketone, or the like can be used.

  The ratio of the silicone oil and the curing agent in the silicone resin composition can be in the range of 0.1 to 2 parts by mass of the curing agent with respect to 10 parts by mass of the silicone oil. Moreover, the ratio of the silicone oil and the solvent in the silicone resin composition can be in the range of 0 to 5 parts by mass of the solvent with respect to 10 parts by mass of the silicone oil. When the solvent ratio is increased, a soft silicone oil rubber can be produced. Conversely, when the solvent ratio is decreased, a hard silicone oil rubber can be produced.

  The resin body 3 may be formed of a resin other than a silicone resin. For example, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, polytetrafluoroethylene, ABS resin (acrylonitrile butadiene styrene resin), AS resin (acrylonitrile styrene resin), acrylic resin, or the like may be used. it can. Alternatively, these resins and silicone resins may be used in combination. However, it is preferable to use a silicone resin. When a silicone resin is used, the sensitivity of the tactile sensor A can be improved.

  Although the hardness of the resin body 3 is not specifically limited, The hardness in the type A based on JISK6253 may be in the range of 20-80. The hardness of the resin body 3 can be measured with a durometer. In addition, the hardness of the magnetic rubber body 1 can be in the range of 10 to 90 or in the range of 20 to 80.

  As shown in FIG. 1A, a magnetic rubber body 1 to which a pair of electrodes 2 and 2 are connected as shown in FIG. 1D is used, and the magnetic rubber body 1 is sandwiched between resin bodies 3 and 3 from both sides. Tactile sensor A in which magnetic rubber body 1 is covered with resin body 3 can be obtained by bonding and integrating with an adhesive or the like. At this time, the electrodes 2 and 2 are preferably formed so as to be exposed to the outside of the resin body 3. Alternatively, the electrodes 2 and 2 may be covered with the resin body 3 and a conductive wire (electrical wiring) may be connected to each electrode 2 so that the conductive wire is exposed to the outside. FIGS. 1B and 1C are views of the magnetic rubber body 1 as viewed from above or obliquely from above, and since the resin body 3 is transparent, the internal state can be confirmed. In addition, the coating method by the resin body 3 is not restricted to the above. For example, the magnetic rubber body 1 is sandwiched between two semi-cured resin bodies 3 and 3 and then completely cured, or after the magnetic rubber body 1 is placed in a mold, the resin is injected into the mold and cured. The magnetic rubber body 1 and the resin body 3 may be integrated.

  The electrode 2 can be a metal plate or a metal piece having electrical conductivity. The metal material may be aluminum, copper, nickel, silver, gold or the like. In addition, as long as there is no problem in continuity, the electrode 2 may be configured by the tip of a conducting wire (electrical wiring 6) or may be configured by a conductive tape.

  In the form of FIG. 1, the electrodes 2 and 2 are disposed on the same surface of the magnetic rubber body 1, but the connection position of the electrodes 2 is not limited to this. The electrodes 2 and 2 may be attached to the magnetic rubber body 1 so as not to contact each other.

  FIG. 2 shows an example of the connection between the magnetic rubber body 1 and the electrodes 2 and 2. The magnetic rubber body 1 is a rectangular sheet, and the electrode 2 is a rectangular flat plate. By attaching the pair of electrodes 2 and 2 to the magnetic rubber body 1, an energized portion of the touch sensor A can be formed.

  2A and 2B show the electrodes 2 and 2 connected to the same surface of the magnetic rubber body 1. In this embodiment, the electrodes 2 and 2 are arranged at different positions in the vertical direction so as to straddle each of the two opposite sides (vertical sides) of the magnetic rubber body 1. It arrange | positions so that a part of edge | side may oppose in a horizontal direction (direction parallel to the surface of the magnetic rubber body 1). Such a configuration is effective when a force is applied to the magnetic rubber body 1 perpendicularly (when a pressing force is applied by contact). That is, since the current flows near the surface of the magnetic rubber body 1 on the electrode side, the current change can be detected with high sensitivity by bringing an object into contact with the electrode side. Further, if the object is brought into contact with the surface opposite to the electrode side, the sensitivity may be lowered, but the electrode 2 is applied when a force that moves the object in the horizontal direction such as shear force or shear force is applied. Since it can suppress that an object contacts with an object, destruction of the electrode 2 can be suppressed.

  FIGS. 2C and 2D show electrodes 2 and 2 connected to each side (front and back) of both sides of the magnetic rubber body 1. And in this form, the electrodes 2 and 2 are arrange | positioned in the position where the position of a vertical direction differs so that each of the two opposite sides (vertical side) of the magnetic rubber body 1 may be straddle | crossed. Further, in this embodiment, when the electrodes 2 and 2 are projected in the vertical direction (direction perpendicular to the surface of the magnetic rubber body 1), part of the sides of the electrodes 2 and 2 are horizontal (surface of the magnetic rubber body 1). Are arranged so as to face each other. Such a configuration is effective when a force is applied in parallel to the magnetic rubber body 1 (when a force is applied so as to be stroked). That is, the current flows through the magnetic rubber body 1 in the thickness direction from the opposite side of the electrode 2 to the other side, so that a current change can be detected with high sensitivity by bringing an object into contact with the magnetic rubber body 1. In addition, since one of the electrodes 2 can be disposed on the side opposite to the contact surface of the object B, the destruction of the electrode 2 can be suppressed.

  2E and 2F show the electrodes 2 and 2 connected to the respective surfaces (front and back) of the magnetic rubber body 1. However, in this embodiment, the electrodes 2 and 2 are disposed at the same position in the vertical direction so as to straddle the two opposite sides (vertical sides) of the magnetic rubber body 1, and the electrodes 2 and 2 are magnetic. It is arrange | positioned so that it may oppose on both surfaces through the rubber body 1. FIG. This configuration is effective when a force is applied in parallel to the magnetic rubber body 1 (when a force is applied so as to be stroked). That is, the current flows in the thickness direction of the magnetic rubber body 1, and the current change can be detected with high sensitivity by bringing the object into contact. In addition, since one of the electrodes 2 can be disposed on the side opposite to the contact surface of the object B, the destruction of the electrode 2 can be suppressed. The electrodes 2 and 2 are opposed to each other with the magnetic rubber body 1 in between, and since the distance between the electrodes 2 and 2 is short, a current easily flows between the electrodes 2 and 2, and a slight current change can be detected. it can.

  FIG. 3 shows an example of a method for measuring an object by the tactile sensor A. As the tactile sensor A, the one described above can be used. In the form of FIG. 3, a method in which the electrodes 2 and 2 are attached to the magnetic rubber body 1 by the method shown in the arrangement examples of FIGS. 2C and 2D is used. The magnetic rubber body 1 is formed as a sheet body (rubber sheet). By forming the magnetic rubber body 1 into a sheet shape, sensitivity can be improved and a thin sensor can be formed. Further, the resin body 3 is also in a sheet shape, and the touch sensor A is formed in a sheet shape. By making the tactile sensor A into a sheet shape, sensitivity can be improved and a thin sensor can be formed.

  In FIG. 3, one of the pair of electrodes 2 is represented as a first electrode 2a, and the other is represented as a second electrode 2b. The first electrode 2a and the second electrode 2b are in contact with the tactile sensor A at positions apart from each other, and are not in contact with each other. The pair of electrodes 2 and 2 are both formed as flat electrodes, with the first electrode 2a at one end on the top surface of the magnetic rubber body 1 and the second electrode 2b at the other end on the bottom surface of the magnetic rubber body 1. It is arranged in the part. In this embodiment, the first electrode 2a functions as a cathode (negative electrode), and the second electrode 2b functions as an anode (positive electrode). The magnetic rubber body 1 to which the electrode 2 is attached is covered with the resin body 3 to constitute the tactile sensor A.

  Below the touch sensor A, an object B which is an object to be inspected is arranged. Then, a voltage is applied between the first electrode 2a and the second electrode 2b, and the tactile sensor A and the object B come into contact with each other or the contact state changes, so that the state shown in FIG. Thus, the force from the object B is applied to the surface of the magnetic rubber body 1 through the resin body 3, and the amount of current between the first electrode 2a and the second electrode 2b changes. The object B can be detected by detecting this amount of current. In FIG. 3B, a current (electron) flow is represented as a current path L.

  In the touch sensor A, each of the electrodes 2 and 2 may be connected by a conducting wire or the like. And a voltage can be applied through this conducting wire. The voltage to be applied is preferably set to be equal to or lower than the allowable voltage of the magnetic rubber body 1. For example, since it has been confirmed that the prototype magnetic rubber body 1 can apply a voltage of up to 33V, it can be made 33V or less. When a higher voltage is applied, a minute current change can be detected, but a current change can be detected even with a small voltage. Therefore, the applied voltage only needs to be greater than 0V, and may be an appropriate voltage such as 5V or less, 10V or less, or 20V or less. Note that this voltage is an absolute value, and the voltage may be applied using the first electrode 2a as an anode and the second electrode 2b as a cathode, contrary to the configuration of FIG.

  In the touch sensor A, the object B may be brought into contact with the touch sensor A from above. In this case, the contact of the object B placed on the touch sensor A can be detected. Thereby, for example, it is possible to detect an ultralight material or a fallen object. It is also possible to arrange the tactile sensor A with the surface in the vertical direction (longitudinal direction) and bring the object B into contact with the surface of the tactile sensor A from the side.

  The contact position of the touch sensor A with the object B is preferably a position between the first electrode 2a and the second electrode 2b. The current flowing between the first electrode 2a and the second electrode 2b usually tries to pass through the shortest distance possible. Therefore, a current passage is formed between the first electrode 2a and the second electrode 2b, and a change in current can be detected with high accuracy when the object B comes into contact with the current passage.

  Here, it has been confirmed that if the magnetic rubber body 1 is used, a current flows between electrodes at arbitrary positions on the rubber surface. Therefore, since electricity easily flows even between electrodes that have a certain distance, it is possible to provide a surface with a large area required to sense a horizontal force such as a shearing force or a shearing force.

  In contact with the object B, it is preferable that the touch sensor A and the object B are brought into contact so that the object B does not contact the electrode 2. When the electrode 2 comes into contact with the object B, the electrode 2 may be broken or damaged when a vertical force, shearing force, shearing force, or the like is applied. Therefore, it is preferable to design so that a current flows through the tactile sensor A between the electrodes 2 and 2 separated by a certain distance.

  The tactile sensor A can detect contact with the object B. When a voltage is applied between the first electrode 2a and the second electrode 2b and the object B is brought into close contact with the tactile sensor A, a force is applied from the object B to the tactile sensor A, and the first electrode The amount of current between 2a and the second electrode 2b changes. For example, this change in the amount of current can be detected as a state in which the rubber magnetic body 1 flows from a state in which no current flows. Alternatively, the change in the amount of current can be detected as a change in the magnitude of the flowing current value. The presence or absence of contact with the object B can be detected by this current change. The tactile sensor A obtained as described above can detect a force of about 0.01 N and can detect the contact of the object B with ultra-high sensitivity.

  Further, the tactile sensor A can detect a force (stress due to contact, contact force) applied upon contact with the object B. As described above, when the touch sensor A and the object B come into contact with each other, the current changes. As the contact force increases, the amount of change in current also increases. Therefore, it is possible to detect the magnitude of force applied by contact and the stress due to contact from the amount of change in current.

  The tactile sensor A can detect whether the surface of the object is a rough surface (a surface having a high surface roughness) or a smooth surface (a surface having a low surface roughness). For example, as the object B to be inspected, an object having a rough surface (a surface having a high surface roughness) or a smooth surface (a surface having a low surface roughness) is used. Alternatively, the object B may be an object having both a rough surface and a smooth surface. When the object B is brought close to the touch sensor A, the object B first contacts the touch sensor A in the vertical direction. Then, a pressing force is applied to the tactile sensor A from the object B, and the tactile sensor A is deformed according to the uneven surface of the surface of the object B, and the deformation is transmitted to the inside so that the surface of the magnetic rubber body 1 is Deform. Due to the uneven deformation of the surface of the magnetic rubber body 1, the amount of current between the first electrode 2a and the second electrode 2b changes. At this time, the degree of change in the amount of current differs depending on the degree of unevenness deformation. Therefore, the roughness of the surface of the object B, such as whether the surface is rough or smooth, can be detected. Further, in a state where the object B and the tactile sensor A are in contact with each other, one or both of the tactile sensor A and the object B are moved and relatively translated in a sliding direction (the object B is stroked with the tactile sensor A). Then, stress or repulsive force is applied to the tactile sensor A from the object B. Then, the surface of the tactile sensor A tries to expand and contract in accordance with the uneven surface of the object B. Due to the uneven deformation of the surface of the touch sensor A, the surface of the magnetic rubber body 1 is also deformed, and the amount of current flowing between the first electrode 2a and the second electrode 2b changes. At this time, the current waveform changes according to the shape of the uneven surface of the object B, that is, the surface roughness, and therefore the roughness of the surface of the object B can be detected.

  The tactile sensor A can detect a change in roughness of the object surface. In the state where the object B and the tactile sensor A are in contact as described above, if one or both of the tactile sensor A and the object B are moved and relatively translated in the sliding direction, stress or repulsion is generated from the object B. A force is applied to the tactile sensor A. Then, the surface of the touch sensor A tries to expand and contract in accordance with the concavo-convex surface of the object B, and the deformation is transmitted to the inside so that the magnetic rubber body 1 tries to deform. The amount of current flowing between the first electrode 2a and the second electrode 2b changes due to the uneven deformation of the surface of the magnetic rubber body 1 as described above. At this time, the current waveform changes according to the shape of the concavo-convex surface of the object B. Therefore, the change in the roughness of the surface of the object B can be detected.

  The tactile sensor A can detect the softness (hardness) of the object. In a state where the object B and the tactile sensor A are in contact with each other, by moving one or both of the tactile sensor A and the object B and relatively moving them in a sliding direction (strike the object B with the tactile sensor A), Stress or repulsive force is applied to the tactile sensor A from the object B. Then, the surface of the touch sensor A tries to expand and contract according to the force applied from the object B, and the deformation is transmitted to the magnetic rubber body 1. At this time, if the object B is hard, the force applied to the touch sensor A is large, and if the object B is soft, the force applied to the touch sensor A is small. The degree of deformation of the magnetic rubber body 1 varies depending on the difference in force, and the amount of current flowing between the first electrode 2a and the second electrode 2b changes. At this time, the current waveform changes according to the softness of the object B, and therefore the softness of the object B can be detected.

  FIG. 4A is an example of an embodiment of the tactile sensor A. FIG. In the tactile sensor A, the unevenness 5 is provided on the surface of the resin body 3.

  The surface of the resin body 3 may be a flat surface, but it is more preferable that the surface of the resin body 3 is provided with irregularities 5 as in the form of FIG. The unevenness 5 is preferably provided on the surface in contact with the object B. That is, it is preferable that the tactile sensor A has the unevenness 5 on the surface in contact with the object B. When the unevenness 5 is provided on the surface of the resin body 3, the current change as described above can be detected with higher accuracy, and the object B can be detected with higher sensitivity. In particular, when the tactile sensor A is provided with the unevenness 5, a horizontal force (striking force) can be detected with high sensitivity. That is, when trying to move the object B in the horizontal direction, the surface of the object B (a rough surface or a smooth surface) comes into contact with the unevenness of the surface to change the shape of the tactile sensor A. Therefore, since a minute force difference can be captured as a current change, a horizontal force (shear force or shear force) can be detected with high sensitivity.

  The unevenness 5 of the resin body 3 is composed of a convex portion 5a protruding outward and a concave portion 5b recessed inward. As the unevenness 5, in order to detect with higher sensitivity, the unevenness 5 in which the concave portion 5b has a groove shape, or the unevenness 5 in which the convex portion 5a has a protruding line (line shape) is preferable.

  The unevenness 5 provided on the surface of the resin body 3 is preferably a fingerprint-like unevenness 5. Although there are many types of human fingerprint shapes, humans can detect an object with high sensitivity by having a fingerprint. Therefore, by providing fingerprint-shaped unevenness 5 on the tactile sensor A, it is possible to increase the tactile sensitivity and sense a rough feeling and a smooth feeling.

  FIG. 5 shows an example of the pattern of the unevenness 5 provided on the resin body 3. The unevenness 5 of the resin body 3 has a concentric pattern as shown in FIG. 5A, a pattern in which a plurality of straight lines are arranged in parallel as shown in FIG. 5B, and a lattice shape as shown in FIG. It is preferable that it is the uneven | corrugated pattern in any one of these patterns. Thereby, the object B can be detected with higher sensitivity. In FIG. 5, the concavo-convex pattern of the concavo-convex 5 is drawn by the center line of the convex portion 5a.

  FIG. 5A shows the concavities and convexities 5 of a concentric circle pattern in which a plurality of circles having different diameters are arranged at the same center position. The circle may be a perfect circle, but may be an ellipse. In this form, the convex part 5a and the concave part 5b are both concentric patterns. In the case of a concentric pattern of concentric circles, direction dependency is reduced, and it is advantageous in that it is possible to capture forces in all directions on the horizontal plane with the same sensitivity.

  FIG. 5B shows the pattern irregularities 5 in which a plurality of straight lines are arranged in parallel at equal intervals. In this form, the convex part 5a and the concave part 5b are each a pattern of a plurality of straight lines (parallel lines). In the case of an uneven pattern of parallel lines, the force when the object is displaced in a direction perpendicular to the direction in which the straight line extends can be detected with high sensitivity.

  FIG. 5C shows the concavo-convex pattern 5 having a lattice pattern in which a plurality of straight lines are arranged in parallel at equal intervals in both the vertical and horizontal directions. The plurality of parallel straight lines are arranged at the same pitch in the vertical direction and the horizontal direction, but may be arranged at different pitches in the vertical direction and the horizontal direction. In this form, the convex part 5a becomes a grid | lattice form, and the recessed part 5b becomes a rectangular shape. In the case of a grid-like concavo-convex pattern, there is a possibility that a force can be detected with high sensitivity when an object moves so as to be randomly displaced in the horizontal direction without regularity.

  The unevenness 5 provided on the surface of the resin body 3 may not be the above pattern. For example, it may be a hexagonal lattice shape, a spiral shape, a honeycomb shape, a mesh shape, or the like. However, in order to be able to detect with high sensitivity and to facilitate production, a regular concavo-convex pattern is preferable, and the above concavo-convex pattern is particularly preferable.

  FIG. 4B is an enlarged view of the unevenness 5 provided on the resin body 3. The width W1 of the convex portion 5a can be set to 0.1 to 3 mm, for example. Moreover, the distance between the adjacent convex parts 5a, ie, the width W2 of the concave part 5b, can be in the range of 0.1 to 10 mm or 0.5 to 5 mm. The width W2 of the concave portion 5b is preferably larger than the width W1 of the convex portion 5a. Thereby, the convex part 5a can be protruded by a narrow width, and a sensitivity can be improved. The pitch at which the convex portions 5a are arranged can be in the range of 0.5 to 10 mm or 1 to 5 mm.

  The height H of the convex part 5a can be 0.1-5 mm, for example. Sensitivity can be increased and the fabrication is easy when the height of the irregularities is within this range. If the height H of the convex portion 5a is too high (the depth of the concave portion 5b is too deep), after the convex portion 5a is crushed, the change that the convex portion 5a tries to recover becomes large, so that the current is increased. May increase or decrease in an unstable manner. Moreover, if the convex part 5a is too high, it is possible to capture a current change such as when it is stroked after contact, but there is a possibility that it is not easy to measure the current change with high accuracy. On the other hand, if the height H of the convex portion 5a is too low, the deformation due to contact with the object is reduced, and the sensitivity may be lowered. Therefore, in order to capture the current change when stroking with high sensitivity, the height of the convex portion 5a is preferably within the above range, and more preferably about 0.5 to 2 mm. For example, the height H of the convex portion 5a can be about 1.5 mm.

  Note that irregularities may be formed on the surface of the magnetic rubber body 1. When unevenness is provided on the surface of the magnetic rubber body 1, the deformation of the resin body 3 can be accurately grasped and the sensitivity can be improved. The shape of the unevenness can be the same pattern as the unevenness 5 on the surface of the resin body 3.

  An example of manufacturing the tactile sensor A will be described with reference to FIGS. FIG. 6 shows an example of manufacturing the magnetic rubber body 1. FIG. 7 shows an example of manufacturing the resin body 3.

  In the manufacture of the magnetic rubber body 1, first, a magnetic mixed fluid in which Ni and, if necessary, Cu are dispersed in a magnetic fluid is prepared. Next, the magnetic mixed fluid is mixed with a liquid elastic polymer material. At this time, a natural rubber material for balloons can be used as the elastic polymer material. In addition, it is preferable to add an elastic polymer material after preparing a uniform magnetic mixed fluid by sufficiently blending Ni (for example, Ni powder) and Cu (for example, Cu powder) with a magnetic fluid for manufacturing. . Thereby, the magnetic rubber material before hardening is prepared as the mixture 1a.

  Further, as shown in FIG. 6, a non-magnetic plate 9 and a permanent magnet 8 are used, and the N pole of the permanent magnet 8a is arranged on one side of a pair of opposed plates 9 (9a, 9b), and the other side. The south pole of the permanent magnet 8b is disposed, and the pair of permanent magnets 8a and 8b are disposed to face each other. The plate 9 can be a resin plate or the like, for example, an acrylic plate. Although the thickness of the plate 9 is not specifically limited, For example, it can be set as the range of 0.01-5 mm, Preferably it can be set as the range of 0.1-1 mm.

  And the mixture 1a obtained by the above is inject | poured into the clearance gap between plate 9a, 9b. At this time, it is preferable to arrange the plates 9a and 9b to face each other, surround the gap between the plates 9a and 9b with a spacer 11 made of a non-magnetic material, and press the mixture 1a with the plate 9. By using the spacer 11, the magnetic rubber body 1 can be adjusted to a desired shape such as a sheet body. And if it makes it harden | cure in presence of a magnetic field, applying a magnetic field in this state, the magnetic rubber body 1 can be obtained.

Here, the reason why the magnetic mixture fluid is sandwiched between the opposing permanent magnets 8a and 8b via the non-magnetic plates 9a and 9b having a predetermined thickness and is cured while applying a magnetic field is to improve conductivity and the like. Therefore, in order to form magnetic clusters made of metal particles such as Ni, Cu, and Fe ₃ O ₄ in the magnetic fluid (MF) in the direction of the magnetic lines of force.

  In the curing step, a magnetic field of 5 to 5.8 gauss or more is applied using a neodymium magnet or the like while the mixture 1a of the magnetic mixed fluid and the rubber material is held in a sheet shape so that the thickness is 1 mm or less. This is preferable for increasing the cluster formation density. It has been confirmed by preliminary experiments that when the magnetic field strength decreases, the cluster formation density decreases, and when the cluster formation density decreases, the electrical and thermal conductivity tends to decrease. Therefore, it is desirable to apply a stronger magnetic field when the thickness is 1 mm or more. By satisfying the above-described magnetic field conditions, it is possible to reliably provide the magnetic rubber body 1 having high electrical and thermal conductivity and high stretchability and elasticity.

  The mixture 1a may be cured by being opened to the atmosphere at room temperature or by heating, similarly to the curing of a general adhesive. In addition, since the clusters are formed by applying a magnetic field before the hardening starts, the hardening usually starts after the formation of the clusters, and it is considered that the structure of the clusters does not depend on the hardening conditions. As the curing, chemical curing using a curing agent or the like may be employed, or the curing agent may be used and heated.

  When the magnetic rubber body 1 is a sheet body, the thickness is preferably 0.1 to 10 mm, and more preferably 0.3 to 3 mm.

  FIG. 7 is an example of manufacturing the resin body 3. In the manufacturing method of FIG. 7, the resin body 3 having a rough surface can be obtained.

  In manufacturing the resin body 3, first, a liquid resin composition is prepared. When the resin body 3 is formed of silicone oil rubber, a silicone composition is prepared by mixing silicone oil, a curing agent, and a solvent as necessary. Then, as shown in FIG. 7, a mold 10 having an uneven surface is used, a frame is formed by surrounding the mold 10 with a spacer 11, and a resin composition is injected into the frame. Then, the resin composition is cured by being sandwiched between the plate 9 and the mold member 10. The resin composition may be cured by opening it to the atmosphere at room temperature or by heating, as in the case of curing a general adhesive. The resin body 3 can be obtained by hardening the resin composition. In addition, the unevenness | corrugation 5 of a suitable pattern can be provided to the resin body 3 in the case of shaping | molding by providing unevenness | corrugation shape in the surface of the mold material 10 so as to correspond to the shape of the unevenness | corrugation 5 of the resin body 3 to form. . Further, if a flat surface mold member 10 having no surface irregularities is used, a flat surface resin body 3 having no irregularities 5 can be obtained.

  When the resin body 3 is a sheet body, the thickness is preferably 0.01 to 5 mm, and more preferably 0.05 to 3 mm. If the thickness of the resin body 3 is too thick, the sensitivity may decrease. In addition, this thickness is the thickness in the position of the recessed part 5b, when the unevenness | corrugation 5 exists.

  In order to form the unevenness 5 on the surface of the resin body 3, a metal wire having an appropriate shape is disposed on a mold 10 having a flat surface, and the resin composition is sandwiched between the plates 9 in that state. May be. By using a metal wire, the unevenness 5 can be easily formed on the surface of the resin body 3.

  Then, as shown in FIG. 1A, the tactile sensor A can be manufactured by attaching the electrodes 2 and 2 to the obtained magnetic rubber body 1 and sandwiching it between the resin bodies 3. The resin body 3 can be attached with an adhesive. A silicone resin adhesive can be used as the adhesive. At this time, if the magnetic rubber body 1 is covered with the resin body 3, the magnetic rubber body 1 can be isolated and sealed from the outside, and the rubber can be hardly deteriorated.

  FIG. 8 shows an example of an embodiment of the tactile sensor A. FIG. 8A is an exploded perspective view, and FIG. 8B is a cross-sectional view. In this tactile sensor A, the magnetic rubber body 1 is sealed with a resinous wrap film 4 inside the resin body 3. The entire magnetic rubber body 1 is wrapped around a wrap film 4 and sealed. Thus, since it can suppress that air penetrate | invades inside and reaches | attains the magnetic rubber body 1 by being sealed by the wrap film 4, it can further suppress that the magnetic rubber body 1 deteriorates. . Moreover, since the wrap film 4 is thin, the sensitivity of the touch sensor A is unlikely to decrease. The thickness of the wrap film 4 may be, for example, 1 to 100 μm, and preferably 5 to 30 μm or 10 to 20 μm.

  As the wrap film 4, a food wrap film or a packaging film can be used. As a material of the wrap film 4, it is possible to use a material such as polyvinylidene chloride, cellophane, polyethylene terephthalate, polyamide synthetic fiber, polyethylene, polypropylene, polyvinyl alcohol, polyvinyl chloride, polymethylpentene alone or in combination. it can.

  The wrap film 4 is preferably a film formed of polyvinylidene chloride. By using polyvinylidene chloride, the magnetic rubber body 1 can be easily sealed to prevent air from entering. Commercially available wrap materials such as Saran Wrap (registered trademark) and Kure Wrap (registered trademark) can be used as the polyvinylidene chloride wrap film.

  The wrap film 4 may be used as a single layer (one sheet), or may be used as a plurality of layers by overlapping a plurality of sheets. Sealing performance can be improved by stacking the wrap films 4. Further, the wrap film 4 may be wound around the rubber magnetic body 1. By wrapping with the wrap film 4, the sealing performance can be enhanced.

  As shown in FIG. 8A, the wrap film 4 is overlaid on the magnetic rubber body 1 obtained by the same method as in FIG. 6, and the resin body 3 obtained by the same method as in FIG. By bonding, the tactile sensor A in which the magnetic rubber body 1 is wrapped in the wrap film 4 can be obtained. An adhesive can be used for adhesion. A silicone adhesive is preferably used as the adhesive. In addition, the adhesive can be provided between the magnetic rubber body 1 and the wrap film 4 and / or between the wrap film 4 and the resin body 3. In the form of FIG. 8, electrical wiring 6 (conductive wire) is attached to the electrode 2. Then, the electrode 2 and the electric wiring 6 are fixed to the magnetic rubber body 1 by covering the electrode 2 and the electric wiring 6 and attaching the conductive tape 7 to the magnetic rubber body 1. By using the conductive tape 7, the electrode 2 and the electrical wiring 6 can be easily attached to the magnetic rubber body 1. In addition, the conductive property can be enhanced by the conductive tape 7, and poor contact between the electrode 2 and the electrical wiring 6 can be reduced. The conductive tape 7 is preferably a double-sided tape. Thereby, the wrap film 4 can be attached in close contact.

According to the present invention, the magnetic rubber body is easy to manufacture, and the normal force and shear force can be detected simultaneously with ultra-high sensitivity by the combination of metal powder (Ni, Cu), magnetic fluid and rubber component. It can be done. That is, in obtaining a magnetic rubber material, a magnetic powder in which metal particles such as copper and nickel having a size of 1 to 200 μm and ferromagnetic particles made of magnetite Fe ₃ O _{4 having a} particle size of 5 to 50 nm are dispersed in water. By using a rubber (also referred to as MCF tactile rubber) in which a fluid is mixed with a rubber component, a highly sensitive tactile sensor can be obtained. In particular, when a natural rubber material for balloons is used, an ultrasensitive tactile sensor that reacts with a weight of about 0.01 N (in other words, when a mass of 1 g is placed) and a current flows through the rubber is obtained. Can do. Moreover, since it can produce by applying a magnetic field as mentioned above, production of a magnetic rubber body is easy. The MCF tactile rubber is rich in elasticity and elasticity, and can provide a tactile sensor that can be detected with extremely high sensitivity.

  In addition, the tactile sensor is in the direction of both the force when pressed perpendicular to the surface of the MCF tactile rubber (vertical stress) and the force when rubbed parallel to the surface (shear stress or shear stress). The electric current flows through the rubber by reacting simultaneously to the force from the rubber.

  If the surface of the tactile sensor (the surface of the resin body) is uneven, especially fingerprint-like unevenness, the current that flows in the rubber when the object is stroked with the tactile sensor (when shear stress is applied) It is possible to measure the roughness of the surface of objects such as uneven surface, cloth, human skin, fruit surface, etc. Also, if there are fingerprint-like irregularities, the softness of the object can be measured when it is stroked with a tactile sensor (when shear stress is applied).

  Further, since the magnetic rubber body is covered with a resin body such as a silicone film, deterioration can be prevented. Further, when the magnetic rubber body is covered with a wrap film such as polyvinylidene chloride, the deterioration can be suppressed to a high level.

  By the way, most of the conventional tactile sensors use strain gauges, piezo elements, and MEMS, and there is no mixed type of metal powder and rubber other than commercially available pressure-sensitive conductive rubber. is there. These materials lack elasticity and elasticity, and are complicated in structure, so that they are not easy to manufacture and are practically expensive. Further, there is no ultra-sensitive one that reacts with a weight of about 0.01 N (in other words, when a mass of 1 g is placed) and a current flows through the rubber. In the case of a commercially available pressure-sensitive conductive rubber, only a method in which electricity starts to flow with a large vertical force of the order of 10 N can be formed by a normal method. Moreover, commercially available pressure-sensitive conductive rubber is poor in elasticity. In the world of robots, ultra-high sensitivity of 0.01N is required, but 0.1N is the limit for commercially available pressure-sensitive conductive rubber. Also, the force when pressed perpendicular to the surface of the pressure-sensitive conductive rubber (normal stress) and the force when rubbed parallel to the surface (shear stress or shear stress) from both directions There is no tactile sensor that responds to force simultaneously and current flows through the rubber. While the human skin sensation is capable of sensing two forces, conventional tactile sensors are not, and only one of them is sensed so that two forces can be sensed (eg, sensor Multiple), the structure becomes complicated and the cost is high. In addition, like a human skin sensation, there is no conventional tactile sensor that can sense a rough feeling and a smooth feeling on the surface of an object. In conventional surface roughness meters, measurement sample pieces must be cut out, and surface processing of large machines such as aircraft relies on the hand of craftsmen, so there is a need for a handy surface roughness measuring instrument that replaces this. . Conventionally, there is nothing that can measure the softness of an object, which is important in the case of medical treatment such as palpation and the examination of the touch of a woman.

  On the other hand, in the present invention, these conventional problems can be solved by forming a tactile sensor using the magnetic rubber body. In particular, when a balloon rubber material is used as the magnetic rubber body, it is rich in elasticity and stretchability, and can be easily manufactured because it is mixed with rubber, and can be obtained at low cost. In addition, by using a water-soluble rubber material for balloons and a water-based magnetic fluid, an ultra-high current flows through the rubber by reacting with a weight of about 0.01 N (in other words, when a mass of 1 g is placed). Sensitivity is obtained. In addition, since the magnetic rubber body is ultra-sensitive, the force (vertical stress) when pressed perpendicular to the surface and the force (shear stress or shear stress) when rubbed parallel to the surface It is possible to detect a change in current flowing through the rubber by reacting simultaneously to forces from both directions. In addition, if the surface of the resin body that covers the magnetic rubber body is further provided with fingerprint-shaped irregularities, it is possible to capture large changes in the current flowing through the rubber, especially due to shear stress, so that a wide variety of object surfaces Can be measured. In addition, when rubber materials for balloons are used, they can swell like balloons, can be extremely stretchable and elastic, and can be detected with ultra-high sensitivity It is.

  Thus, according to the tactile sensor, an object can be detected with ultra-high sensitivity. Therefore, as a preferable application example of the tactile sensor, a pressure-sensitive sensor using the resin body surface as a detection unit, a pressure-sensitive switch using the resin body surface as a contact, and the like can be cited. In this case, since electricity flows quickly in the thickness direction of the magnetic rubber body, it is preferable to have a design that senses electricity in the thickness direction. Further applications are possible, for example, a tactile sensor can be mounted on a robot. In addition, inspection of polished surfaces in the machining, aircraft and automobile industries, touch inspection of clothes in the clothing and garment industry, medical inspection such as palpation of breast cancer checkers, inspection of female touch in the cosmetics industry, food inspection, bio-related It can be applied over a wide range, such as biological touch inspection.

(Magnetic rubber example 1)
Nickel powder (average length 3-7 μm, elongated shape, “123” manufactured by Yamaishi Metal Co., Ltd.) and copper powder (average length 8-10 μm, elongated shape, “MF-D2” manufactured by Yamaishi Metal Co., Ltd.) 20 g And a natural rubber material for balloons (HIRATECH) (May) with 15g of magnetic fluid [MF] (water-based, containing Fe ₃ O ₄ particles, 35 wt%, “W-35” manufactured by Taiho Kogyo Co., Ltd.) (“NR-LATEX”) 80 g and mixed. This mixture was filled in an apparatus as shown in FIG. 6 and cured under a magnetic field by sandwiching it between non-magnetic plates between opposing permanent magnets. Thereby, the magnetic rubber body (19 mm × 24 mm × 1 mm) of magnetic rubber example 1 was produced.

(Magnetic rubber example 2)
2 g of nickel powder (average length 3-7 μm, elongated shape, “123” manufactured by Yamaishi Metal Co., Ltd.) and 2 g of copper powder (average length 8-10 μm, elongated shape, “MF-D2” manufactured by Yamaishi Metal Co., Ltd.) MCF consisting of 4 g of magnetic fluid [MF] (MSGS60, kerosene base, containing Fe ₃ O ₄ particles, 50 wt%, manufactured by Ferrotec Co., Ltd.), and conductive paste consisting of carbon powder (of agent A and agent B) 3 g of “SH-3A” manufactured by Fujikura Kasei Co., Ltd. consisting of two liquids was added to 10 g of silicone oil rubber (SH95550, manufactured by Toray Dow Corning Silicone Co., Ltd.) and mixed. This mixture was filled in an apparatus as shown in FIG. 6 and cured under a magnetic field by sandwiching it between non-magnetic plates between opposing permanent magnets. This produced the magnetic rubber body (11 mm x 16 mm x 0.5 mm) of the magnetic rubber example 2.

(Pressure-sensitive rubber examples 1 to 3)
The following pressure-sensitive conductive rubbers were used as pressure-sensitive rubber examples 1 to 3. The specifications are as follows.
Pressure-sensitive rubber example 1: Pressure-sensitive conductive rubber sample (carbon powder mixed, thickness 1 mm) manufactured by Yokohama Rubber Co., Ltd.
Pressure-sensitive rubber example 2: “CSA / PK” (thickness 1 mm) manufactured by PCR Technical Co., Ltd.
Pressure-sensitive rubber example 3: “CSA” (thickness 1 mm) manufactured by PCR Technical Co., Ltd.

(Test Example 1)
Two electrodes were separated and connected to the rubbers of magnetic rubber examples 1 and 2 and pressure-sensitive rubber examples 1 to 3. A normal force was gradually applied to the rubber. Table 1 shows the vertical force (contact force at which pressure starts to be sensed) when electricity first flows and the electrical resistance at that time.

  As shown in Table 1, in the rubber of magnetic rubber example 1, a current flows when a normal force of 0.0149 N is applied, and the electric resistance at that time is 3491 Ω, which is higher sensitivity than other rubbers.

Table 2 shows the sensing ability when the current in the rubber of magnetic rubber example 1 starts to flow.

FIG. 9 is a graph showing changes in the amount of current when a normal force is applied to magnetic rubber examples 1 and 2. The graph shows that the rubber of magnetic rubber example 1 is highly sensitive.

  FIG. 10 is a photograph when the rubber of magnetic rubber example 1 is stretched with a finger (F). Since this rubber (magnetic rubber body 1) is made of natural rubber for balloons, it has excellent stretchability and elasticity. That is, it is more elastic than the silicone oil rubber type like the magnetic rubber example 2, is soft and swells like a balloon. Such properties are considered to contribute to the improvement of sensitivity.

  Thus, the rubber (magnetic rubber body) of magnetic rubber example 1 has a large electric resistance when the normal force is very small, and the electric resistance decreases with a slight increase in the normal force. There has been no ultra-sensitive rubber so far. For this reason, it can utilize for a sensor as switching.

  Here, when natural rubber for balloons is applied rather than silicone oil rubber, the reason why current flows with a smaller vertical force is that silicone oil rubber is better compatible with kerosene, whereas balloon natural rubber is better compatible with water. This is probably because the structure in which water flows more easily in the rubber than in the case of using kerosene.

  Therefore, an ultra-sensitive tactile sensor can be obtained by attaching an electrode to the rubber magnetic body of magnetic rubber example 1 and coating it with a resin body.

(Experimental device for tactile sensor)
FIG. 11 shows an experimental apparatus for measuring a change in current flowing in the magnetic rubber body when a shearing force or a vertical force is applied to the tactile sensor.

  In the experimental apparatus of FIG. 11, each electrode 2 of the tactile sensor A is connected to a voltage application mechanism 15 that applies a voltage between the electrodes 2 and 2 via an electrical wiring 6. The electric wiring 6 is also connected to a current amount measuring mechanism (not shown) such as an ammeter. In this experimental apparatus, a support 14 that supports the tactile sensor A in a planar shape is disposed on the surface of the tactile sensor A opposite to the contact surface of the object B. When the tactile sensor A contacts the object B, the tactile sensor A Suppresses bending. The support 14 is connected to the actuator 13 and operates in a direction parallel to the surface of the tactile sensor A. A load cell 12 for measuring stress applied when moving in parallel is provided between the actuator 13 and the support 14. On the other hand, the object B is placed on the placing table 21. The mounting table 21 is moved upward or downward by an elevating mechanism 20 such as an actuator. A load cell 22 for measuring stress when a force is applied in the vertical direction is provided below the object B on the mounting table 21.

  By using the experimental apparatus as described above, it is possible to measure the relationship between force and current change when a load is applied.

(Test Example 2)
Using the experimental apparatus of FIG. 11, a rubber body not covered with the resin body 3 was attached instead of the touch sensor A, and the sensitivity of the rubber body itself was investigated. Here, the distance between the electrodes was 12 mm. And the voltage 33V was applied between electrodes, and the electric current was measured.

FIG. 12 shows the inspected object (object B) used in this test. As the object to be inspected (object B), two kinds of sheet-like objects are used. Specifically, an object B ₁ that forms a smooth surface uses an acrylic plate having a smooth surface, and an object B ₂ that forms a rough surface. A sandpaper with an uneven surface was used. Then, sandpaper (object B ₂ ) was fixed and arranged on a part of the surface of the acrylic plate (object B ₁ ), and these surfaces were stroked with a magnetic rubber body from the acrylic plate to the sandpaper.

  In the test, first, the object to be inspected was vertically moved upward by the elevating mechanism 20, the object to be inspected was brought close to the magnetic rubber body 1, and the magnetic rubber body 1 and the object to be inspected (object B) were brought into contact with each other. The normal force applied at that time was measured by the load cell 22. Further, the magnetic rubber body 1 in contact with the object to be inspected was translated by the actuator 13 and swept on the object to be inspected at a sweep speed of 1.7 mm / s. The parallel stress (shearing force) applied at that time was measured with the load cell 12. Further, the moving distance of the object to be swept was measured with a laser displacement meter. Note that the object to be inspected was swept against the surface between both electrodes of the magnetic rubber body 1 so that the object to be inspected did not hit the electrode 2.

  The acrylic plate used for the test has a smooth surface with a mirror-finished surface with a surface roughness of Ra = 0.19 μm, Ry = 7.1 μm, and Rq = 0.37 μm. The sandpaper has a rough surface with a rough surface. As this rough surface, sandpaper having different surface roughness shown in Table 3 was used. A surface roughness meter (“SJ-401” manufactured by Mitutoyo Corporation) was used for measuring the surface roughness.

And it boiled and tested from the smooth surface (acrylic board) to the rough surface (sandpaper). The magnetic rubber body moves on the surface of the acrylic plate immediately after the measurement is disclosed, and moves on the surface of the sandpaper from the middle.

  FIG. 13 shows a change in the electric current flowing in the rubber when the magnetic rubber body obtained by the magnetic rubber example 1 is continuously boiled from the smooth surface to the surface of the object having the uneven surface. The horizontal axis indicates the sweep time. In this graph, when the magnetic rubber body is in contact with the object to be inspected and a vertical force is applied, the time when the sweep is started (the time when the parallel movement is started by the actuator) is started (0 [s]). It is said.

In FIG. 13, the graph of the current waveform in the case of each roughness is shown. In this graph, time of B _C is the boundary of the smooth surface and the rough surface. That, B _C point in the graph is the starting point to begin stroking the surface of sandpaper (when replacing the acrylic plate sandpaper). In addition, since the magnetic rubber body is reattached for every measurement with respect to various rough surfaces, the current value before the start of the sweep differs slightly for each experiment. Therefore, in order to more clearly see the difference in the current change between the smooth surface and the rough surface, the current on the vertical axis in the graph is corrected by correcting the current value before the start of sweeping by the magnetic rubber body to zero. doing.

  From the graph of FIG. 13, it can be seen that the current is changed by moving from the smooth surface to the rough surface. That is, when the rough surface of the sandpaper is boiled, the current decreases once, but the current tends to gradually increase. This is considered to be because the rubber surface is caught by the unevenness of the rough surface when entering the rough object surface.

  Next, the same test was performed on a commercially available pressure-sensitive conductive rubber, and the case of using a commercially available pressure-sensitive conductive rubber and the case of a magnetic rubber body (MCF rubber) using natural rubber for balloons, A comparison was made.

  FIG. 14 shows changes in the current flowing in the rubber when a commercially available pressure-sensitive conductive rubber (pressure-sensitive rubber example 4) is boiled on the surface of an object having an uneven surface. The smooth surface is an acrylic plate surface having a surface roughness Ra = 0.19 μm, Ry = 7.1 μm, and Rq = 0.37 μm, as described above. As the rough surface, six types of sandpaper shown in Table 3 were used. Moreover, the experimental apparatus shown in FIG. 11 was used. The pressure-sensitive conductive rubber of pressure-sensitive rubber example 4 is a pressure-sensitive conductive rubber sample (carbon powder mixed, thickness 1 mm) manufactured by Yokohama Rubber Co., Ltd.

  As shown in the graph of FIG. 14, the pressure-sensitive conductive rubber has a change in current waveform when the rough surface is boiled from the smooth surface compared to the magnetic rubber body according to magnetic rubber example 1. However, the difference is small. Also, the difference in current waveform due to the surface roughness of the rough object surface is small. Therefore, it was confirmed that the magnetic rubber body discriminated the difference between the smooth surface and the rough surface as compared with the commercially available pressure-sensitive conductive rubber.

Example 1
A magnetic rubber body of magnetic rubber example 1 was used, and this was covered with a silicone rubber which is a resin body to produce a tactile sensor. The coating method with a resin body was performed by a method as shown in FIG. The specific procedure is shown below.

  First, 60 g of silicone oil (KE-1300T, manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed with 10 g of thinner and 6 g of a curing agent and cured to produce two silicone oil rubbers as the resin body 3. The resin body 3 has a thickness of about 0.09 to 1.25 mm. With this pair of silicone oil rubbers, the magnetic rubber body of magnetic rubber example 1 was sandwiched and covered. At this time, a thin electrode plate having a thickness of 0.04 to 0.07 mm was attached to the surface of the magnetic rubber body as the electrodes 2 and 2 so that the end portion of the electrode plate protrudes from the resin body 3 and is exposed to the outside. Thus, a tactile sensor in which MCF rubber was covered with a resin body and was shielded from air was obtained.

  FIG. 15 shows a photograph of the tactile sensor A obtained in Example 1. The tactile sensor A can be used as a sensor for detecting a shearing force, a shear stress, and the like.

(Example 2)
The magnetic rubber body of magnetic rubber example 1 was used, and this was covered with uneven silicone rubber to produce a tactile sensor with surface unevenness. The coating method with a resin body was performed by the method shown in FIG. The specific procedure is shown below.

  First, 60 g of silicone oil (KE-1300T, manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed with 10 g of thinner and 6 g of a curing agent and cured to produce two silicone oil rubbers as the resin body 3. At this time, a mold material is used for one silicone oil rubber, and a concentric circle having a convex portion (crest) height of 1.5 mm, a convex portion (crest) width of 0.8 mm, and a spacing between the convex portions of 1.2 mm. A fingerprint shape was provided on the surface of the silicone oil rubber. As a result, a resin body 3 having irregularities 5 was obtained. The thickness of the resin body 3 is about 0.09 mm at the position of the concave portion and about 1.25 mm at the position of the convex portion. With these two silicone oil rubbers, the magnetic rubber body of magnetic rubber example 1 was sandwiched and covered. At this time, a thin electrode plate having a thickness of 0.04 to 0.07 mm is attached as the electrodes 2 and 2 to the surface of the magnetic rubber body, and an electric wiring 6 (conductor) having a wire diameter of φ0.06 mm is attached to the electrode plate as a resin body. Attached so as to jump out of 3 to the outside. As a result, a tactile sensor with surface irregularities in which MCF rubber was covered with a resin body and was shielded from air was obtained.

  FIG. 16 shows a photograph of the tactile sensor with surface irregularities obtained in Example 2. The tactile sensor A can be used as a sensor for detecting a shearing force, a shear stress, and the like.

(Examples A1 to A4 and B1 to B4)
The following were produced as magnetic rubber bodies. First, 40 g of nickel powder (average length 3-7 μm, elongated shape, “123” manufactured by Yamaishi Metal Co., Ltd.) and copper powder (average length 8-10 μm, elongated shape, manufactured by Yamaishi Metal Co., Ltd. “MF-D2”) MCF consisting of 60 g and 14 g of magnetic fluid [MF] (water-based, containing Fe ₃ O ₄ particles, 35 wt%, “W-35” manufactured by Taiho Kogyo Co., Ltd.) ) "La-Ratex" manufactured by Hiratek)) and mixed. This mixture was filled in an apparatus as shown in FIG. 6 and cured under a magnetic field by sandwiching it between non-magnetic plates between opposing permanent magnets. Thus, a magnetic rubber body (19 mm × 24 mm × 0.5 mm) of magnetic rubber example 1 was produced.

  Moreover, the silicone oil rubber which has an unevenness | corrugation (fingerprint) and the flat silicone oil rubber which does not have an unevenness | corrugation were produced with the apparatus shown in FIG. Here, in each Example, as shown in Table 4, a silicone oil rubber having different hardness and uneven pattern was produced. The hard silicone oil rubber used in Examples A1 to A4 is prepared by curing silicone oil without diluting with thinner. That is, 60 g of silicone oil (KE-1300T, manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed with 6 g of a curing agent and cured to prepare a hard silicone oil rubber as the resin body 3. Moreover, the soft silicone oil rubber used in Examples B1 to B4 was prepared using a silicone resin composition having the same composition as in Examples 1 and 2. In other words, 60 g of silicone oil (KE-1300T, manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed with 10 g of thinner and 6 g of a curing agent to cure, thereby producing a soft silicone oil rubber as the resin body 3. The thickness of each silicone oil rubber was 0.09 mm. When the surface has irregularities, this thickness is the thickness of the portion spread in a planar shape as a sheet excluding the convex portion, that is, the thickness at the position of the concave portion.

  The unevenness was formed using a mold material when the silicone oil rubber was cured. The height of the convex portion (mountain) was 1.5 mm, the width (W1) of the convex portion (mountain) was 0.8 mm, and the interval between the convex portions (width W2 of the concave portion) was 1.2 mm.

(Test Example 3)
Using the experimental apparatus of FIG. 11, the tactile sensor A was attached, the surfaces of objects having different roughnesses were swept, and the sensitivity of the tactile sensor A of Examples A1 to A4 and B1 to B4 was tested. Here, the distance between the electrodes was 12 mm. And the voltage 33V was applied between electrodes, and the electric current was measured. As the object, plural types of sandpaper having a rough surface were used. A surface roughness meter (“SJ-401” manufactured by Mitutoyo Corporation) was used for measuring the surface roughness.

  A smooth surface or a rough surface can be expressed as a physical quantity such as Ra, Ry, Rq, etc., which are indicators of surface roughness. Moreover, in the test of the tactile sensor, it is estimated that the smooth feeling and the rough feeling are expressed by a change in current flowing in the rubber corresponding to the surface roughness index such as Ra, Ry, Rq. Therefore, in this test, Ra, Ry, and Rq were used as indices of surface irregularities of the object to be boiled (inspected object), and the relationship with the current change was examined.

  In the test, first, the object to be inspected was vertically moved upward by the lifting mechanism 20, the object to be inspected was brought close to the tactile sensor, and the tactile sensor and the object to be inspected (object B) were brought into contact with each other. The normal force applied at that time was measured by the load cell 22. Further, the magnetic rubber body 1 in contact with the object to be inspected was translated by the actuator 13 and swept on the object to be inspected at a sweep speed of 1.7 mm / s. The parallel stress (shearing force) applied at that time was measured with the load cell 12. Further, the moving distance of the object to be swept was measured with a laser displacement meter. The object to be inspected was swept by touching the tactile sensor so that the object to be inspected did not hit the electrode 2 or the electric wiring 6.

  In the tactile sensor, the smaller the surface roughness of the object surface, the smaller the change in the current waveform, and it is expected that the surface roughness of the object surface to be stroked and the current waveform have a certain law.

FIG. 17, FIG. 18, and FIG. 19 are graphs showing the respective current amounts as Ra _{, E} , Ry _{, E} , Rq _{, and E} for Ra, Ry, and Rq, which are indicators of surface roughness. 17 shows a graph of Ra, FIG. 18 shows a graph of Ry, and FIG. 19 shows a graph of Rq.

From the graphs of FIGS. 17 to 19, there is a correlation between Ra, Ry, Rq and Ra _{, E} , Ry _{, E} , Rq _{, E,} and there is a tendency that the change in the current waveform increases as the roughness increases. It was confirmed that there was. And the following matter was confirmed about the sensitivity which detects roughness.

<Summary of sensitivity due to unevenness>
When the concavo-convex pattern is a parallel line, regardless of the surface roughness, the harder silicone oil rubber (Example A2) has better sensitivity than the softer one (Example B2).
When the concavo-convex pattern is a concentric circle, regardless of the surface roughness, the softer silicone oil rubber (Example B3) has better sensitivity than the harder one (Example A3).
When the silicone oil rubber is hard, the concavo-convex pattern is more sensitive to the parallel line (Example A2) than the grid (Example A4) regardless of the surface roughness.
When the silicone oil rubber is soft, the concavo-convex pattern is more sensitive to the parallel line (Example B2) than the grid-like one (Example B4) except when the surface roughness is small. Further, in the grid-like direction (Example B4), when the surface roughness is small, it is overestimated that the silicone oil rubber is soft.
-When there is no unevenness (Examples A1 and B1), the sensitivity is lower than the unevenness, except when the surface roughness is small, regardless of whether the silicone oil rubber is hard or soft. Moreover, when there is no unevenness (Examples A1 and B1), when the surface roughness is small, it is overestimated that the silicone oil rubber is soft.

  Further, the following operation was performed in order to select conditions with suitable detection sensitivity. First, assuming that the relationship between the surface roughness and the current amount is better in the linear direction (proportional relationship), the silicone oil rubber is hard and the concave and convex pattern is parallel (Example A2) is excluded from this condition. Also, the silicone oil rubber was hard and the concavity and convexity pattern was concentric (Example A2), which was excluded because of its low sensitivity.

  20, FIG. 21 and FIG. 22 are graphs showing the conditions selected from FIGS. 17 to 19 based on the above results. 20 shows a graph of Ra, FIG. 21 shows a graph of Ry, and FIG. 22 shows a graph of Rq. For comparison, there is no unevenness (Examples A1 and B1). Example A4 (hard; lattice-like), Example B3 (soft; concentric circles), and Example B2 (soft; parallel) are more sensitive in this order than the case of Example A1 or Example B1 without the irregularities. Well, the graph is also close to linear (proportional relationship). In conclusion, in Example A4 (hard; lattice-like), Example B3 (soft; concentric circles), and Example B2 (soft; parallel lines), it is confirmed that the sensor has excellent sensitivity as a tactile sensor and has high engineering utility value. It was done.

(Example 3)
Using the magnetic rubber body of magnetic rubber example 1, this was wrapped and sealed with a polyvinylidene chloride wrap film, and further coated with silicone rubber having irregularities to produce a tactile sensor in which the magnetic rubber body was sealed with the wrap film. . The covering method with the wrap film and the resin body was performed by the method shown in FIG. The specific procedure is shown below.

  First, 60 g of silicone oil (KE-1300T, manufactured by Shin-Etsu Chemical Co., Ltd.) was mixed with 10 g of thinner and 6 g of a curing agent and cured to produce two silicone oil rubbers as the resin body 3. At this time, a mold material is used for one silicone oil rubber, and a concentric circle having a convex portion (crest) height of 1.5 mm, a convex portion (crest) width of 0.8 mm, and a spacing between the convex portions of 1.2 mm. A fingerprint shape was provided on the surface of the silicone oil rubber. As a result, a resin body 3 having irregularities 5 was obtained. The thickness of the resin body 3 is about 0.09 mm at the position of the concave portion and about 1.25 mm at the position of the convex portion.

  Further, a thin electrode plate made of aluminum having a thickness of 0.04 to 0.07 mm is attached as the electrodes 2 and 2 to the surface of the magnetic rubber body of the magnetic rubber example 1, and an electric wire having a wire diameter of φ0.06 mm is attached to the electrode plate. The wiring 6 (conductive wire) was attached with a conductive double-sided tape (manufactured by 3M Corporation).

  Then, a silicone adhesive (silicone RTV manufactured by Toray Dow Corning Co., Ltd.) is applied to both surfaces of the magnetic rubber body to which the electrodes are attached. Further, a polyvinylidene chloride wrap film (Saran Wrap (registered trademark) or Kurewrap ( Registered trademark)). Next, a silicone adhesive (silicone RTV, manufactured by Toray Dow Corning Co., Ltd.) was applied to both surfaces of the magnetic rubber body sealed with the wrap film, and the silicone oil rubber produced as described above was further laminated and adhered. Thereby, the rubber magnetic body was sealed with the wrap film, and the tactile sensor A having high air and moisture blocking properties was obtained.

  When the electrical conductivity (resistance) of the tactile sensor A of Example 3 was examined, it was 0.02 to 0.14Ω immediately after production, 0.05 to 10Ω after 1 day from production, and 0.09 to 80Ω after 6 days from production. It was. The electrical conductivity (resistance) of the tactile sensor A produced in the same manner except that a polyvinylidene chloride wrap film is not used is 0.02 to 0.14Ω immediately after production, 1 to 100 kΩ one day after production, and 6 from production. After 1 day, it was 1 MΩ or more (not energized), and it was confirmed that the deterioration was suppressed by sealing the film with a wrap film.

  Various developments are expected for the tactile sensor as described above. For example, it can measure the roughness of objects that are difficult to measure with a surface roughness meter (such as clothes and skin of animals and plants), or measure some of the surface during the production and inspection of large objects (for example, the surface of a large turbine blade). Conventionally, measurement in the case where it is difficult to measure the surface roughness, such as measurement without scratching).

Further, not only the rough surface but also a smooth surface such as a mirror-finished surface such as an acrylic plate can be measured with a tactile sensor. In addition, the smooth feeling and the rough feeling when the object surface is boiled can be expressed as physical quantities by Ra _{, E} , Ry _{, E} , Rq _{, E ,} which are defined in the same manner as the surface roughness index of the current waveform. It is possible to digitize the smoothness and roughness.

A tactile sensor B object 1 magnetic rubber body 2 electrode 3 resin body 4 wrap film 5 unevenness 5a convex portion 5b concave portion 6 electrical wiring 7 conductive tape 8 permanent magnet 9 plate 10 mold material 11 spacer

Claims (10)

  A pair of electrodes is attached to a magnetic rubber body obtained by curing a mixture containing a magnetic fluid and a magnetic mixed fluid containing Ni and a rubber component in the presence of a magnetic field, and the magnetic rubber body is covered with a resin body. A tactile sensor characterized by   The tactile sensor according to claim 1, wherein the resin body is formed of a silicone resin.   The tactile sensor according to claim 1, wherein unevenness is formed on a surface of the resin body.   The tactile sensor according to claim 3, wherein the unevenness of the resin body is a concavity and convexity pattern selected from a concentric circle pattern, a pattern in which a plurality of straight lines are arranged in parallel, and a lattice pattern.   The tactile sensor according to claim 1, wherein the magnetic rubber body is sealed with a resinous wrap film inside the resin body.   The tactile sensor according to claim 5, wherein the wrap film is a film formed of polyvinylidene chloride.   The tactile sensor according to claim 1, wherein the magnetic mixed fluid contains Cu.   The tactile sensor according to claim 1, wherein the rubber component is a rubber material for balloons.   It is a sheet form, The tactile sensor of any one of Claims 1-8 characterized by the above-mentioned.   The tactile sensor according to any one of claims 1 to 9, wherein any one or more selected from contact of an object, contact force, surface roughness, and softness is detected.