JP5530798B2 - Capacitance type sensor and sensor mounting structure - Google Patents

Description

  The present invention relates to a capacitive sensor and a sensor mounting structure that are arranged on, for example, an arm of a nursing robot and can detect a load from a change in capacitance.

  For example, service robots that provide services to humans, such as nursing robots, mobile robots, and pet robots, require softness when touched by humans, that is, softness of the exterior. . On the other hand, a tactile sensor that is attached to a service robot and detects human contact is required to have high sensitivity.

  Patent Document 1 discloses a piezo film sensor as a tactile sensor for a robot. The skin of the robot has two silicone rubber layers. The piezo film sensor is embedded between two silicone rubber layers. The hard piezo film sensor is covered from the front side with a soft silicone rubber layer. For this reason, in the case of the robot described in this document, the hard piezo film sensor does not directly contact the human when the human contacts the robot. Therefore, a human who touches the robot can obtain a soft tactile sensation.

JP 2005-161450 A

  However, the piezo film sensor is covered with a silicone rubber layer. For this reason, the load input to the skin of the robot is transmitted to the piezo film sensor through the silicone rubber layer. Therefore, the sensitivity of the piezo film sensor is lowered.

  Further, in order to prevent the feel of a hard piezo film sensor from appearing outside via the silicone rubber layer, it is necessary to increase the thickness of the silicone rubber layer to some extent. In this respect as well, the sensitivity of the piezo film sensor is lowered.

  Here, in order to improve the sensitivity of the piezo film sensor, the piezo film sensor may be disposed on the skin surface of the robot. However, in this case, a human who touches the robot, that is, the piezo film sensor, receives a hard tactile sensation. Thus, it is difficult to achieve both the softness of the exterior of the robot and the high sensitivity of the sensor.

  In addition, it is preferable that the load measurement range of the tactile sensor is wide. That is, the tactile sensor is disposed on the arm portion or the chest portion of the service robot that contacts a human. For example, when the service robot lifts a person with only the arm, the weight concentrates on the arm. For this reason, a large load is applied to the tactile sensor. On the other hand, when a human strokes the arm of the service robot, a small load is applied to the tactile sensor. In this way, loads of any magnitude are input to the tactile sensor depending on the situation. Therefore, it is preferable that the load measurement range of the tactile sensor is wide.

  However, in the case of a conventional tactile sensor, the load measurement range is narrow. For this reason, it is necessary to use two types of sensors having different measurement ranges for a part to which a large load is applied and a part to which a small load is applied.

  The capacitive sensor of the present invention has been completed in view of the above problems. An object of the present invention is to provide a capacitive sensor that is flexible and has a wide load measurement range. Another object of the present invention is to provide a sensor mounting structure that can achieve both the softness of the exterior of the service robot and the high sensitivity of the sensor.

(1) In order to solve the above-mentioned problem, a capacitive sensor of the present invention is made of an elastomer, and a dielectric formed by laminating a plurality of dielectric layers having different spring constants in the laminating direction, and the dielectric A front electrode having an elastomer disposed on the front side and a conductive filler filled in the elastomer; and an elastomer disposed on the back side of the dielectric and the conductive filler filled in the elastomer. and the back side electrode, comprising: a.

  The capacitance type sensor of the present invention includes an elastomer dielectric, and a front electrode and a back electrode mainly composed of an elastomer. For this reason, it is more flexible than a piezo film sensor. Further, the dielectric, the front side electrode, and the back side electrode can be expanded and contracted integrally. Therefore, there is little possibility that the front-side electrode or the back-side electrode regulates the expansion and contraction of the dielectric.

  The dielectric of the capacitive sensor of the present invention is formed by laminating a plurality of dielectric layers. FIG. 1 is a schematic diagram showing the relationship between the load and capacitance of the capacitive sensor of the present invention. In addition, FIG. 1 is for demonstrating the effect | action of the electrostatic capacitance type sensor of this invention. The shape, inclination, number of lines (number of dielectric layers), etc. of the dielectric layers a and b in FIG. 1 do not limit the capacitive sensor of the present invention.

  As shown in FIG. 1, the dielectric is formed by laminating a dielectric layer a and a dielectric layer b. The spring constant in the stacking direction of the dielectric layer a is smaller than the spring constant in the stacking direction of the dielectric layer b. For this reason, when the same load is input, the dielectric layer a is compressed more largely than the dielectric layer b. Accordingly, the amount of change in capacitance is greater in the dielectric layer a than in the dielectric layer b. As shown by a thick line in FIG. 1, a section in which the capacitance changes substantially linearly with respect to the load is a section in which the dielectric layers a and b can be effectively used to detect the load.

  In the low load region A where the load is small, the capacitance of the dielectric layer a and the dielectric layer b changes substantially linearly with respect to the load. Therefore, both the dielectric layer a and the dielectric layer b can be used for load detection. However, the slope of the dielectric layer a (capacitance change amount / load change amount) is larger than that of the dielectric layer b. That is, the sensitivity of the dielectric layer a is higher than that of the dielectric layer b. For this reason, the dielectric layer a mainly functions for detecting the load.

  On the other hand, in the high load region B where the load is large, the dielectric layer a is completely crushed, and the capacitance does not change much even if the load changes. On the other hand, even in the high load region B, the capacitance of the dielectric layer b changes substantially linearly with respect to the load. For this reason, in the high load region B, the dielectric layer b mainly functions for detecting the load. The same applies when three or more dielectric layers having different spring constants in the stacking direction are stacked.

  As described above, according to the capacitive sensor of the present invention, it is possible to detect the load not only in the low load region A but also in the high load region B, as compared with the case where only the dielectric layer a is disposed alone. . Therefore, according to the capacitive sensor of the present invention, the load measurement range is widened. In addition, the sensitivity in the low load region A can be increased as compared with the case where only the dielectric layer b is disposed alone.

  (1-1) Preferably, in the configuration of (1), only a single layer is arranged in the stacking direction.

  According to this configuration, (a) when a plurality of conventional capacitive sensors of (front side electrode-single layer dielectric layer-back side electrode) are stacked, or (b) a plurality of capacitive sensors of the present invention. Compared to the case of stacking (in this case, of course, included in the configuration of (1) above), the number of electrodes arranged is reduced. Further, since the number of electrodes arranged is small, the electrical configuration is simplified.

  In the cases (a) and (b), the input load is transmitted from the front-side capacitive sensor to the back-side capacitive sensor. For this reason, the load detection timing is shifted between the front-side capacitive sensor and the back-side capacitive sensor. Therefore, it is necessary to synchronize the detection data of each capacitive sensor. On the other hand, in this configuration, it is not necessary to synchronize the detection data. Also in this respect, the electrical configuration is simplified.

  (1-2) Preferably, in the configuration of the above (1), the elastomer that is a material of the dielectric layer is silicone rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, It is better to set it as the structure containing 1 or more types chosen from chlorinated polyethylene and urethane rubber. According to this configuration, the dielectric constant of the dielectric layer is increased. For this reason, an electrostatic capacitance can be enlarged.

  (1-3) Preferably, in the configuration of (1), at least one of the elastomer that is a material for the front electrode and the elastomer that is a material for the back electrode is a silicone rubber or an ethylene-propylene copolymer. It is better to have one or more types selected from rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, and urethane rubber. Good. According to this configuration, the elasticity of at least one of the front side electrode and the back side electrode is increased. For this reason, at least one of the front-side electrode and the back-side electrode and the dielectric are easily expanded and contracted integrally.

(2) In the configuration of the above (1), the 25% compressive load in JIS K 6767 of the dielectric layer is not good is better to adopt a configuration is at least 0.001 MPa 0.01 MPa or less.

  When the 25% compressive load (hereinafter referred to as “25% compressive load”) in JIS K 6767 is large, the dielectric layer becomes hard. For this reason, the spring constant in the laminating direction and the surface direction (direction orthogonal to the laminating direction) is increased. On the other hand, when the 25% compressive load is small, the dielectric layer becomes soft. For this reason, the spring constants in the stacking direction and the surface direction are reduced.

  The reason why the 25% compressive load is set to 0.001 MPa or more is that when it is less than 0.001 MPa, the dielectric layer may be crushed by a low load such as contact, and measurement with a high load may not be possible. .

  The reason why the 25% compressive load is set to 0.01 MPa or less is that when the pressure exceeds 0.01 MPa, the dielectric layer is too hard. For example, when a capacitive sensor is used for a service robot, if the 25% compressive load of the dielectric layer exceeds 0.01 MPa, the dielectric layer is difficult to deform even if a load in the human body weight region is applied. is there.

(3) Preferably, in the configuration of the above (1) or (2), each of the front side electrode and the back side electrode has a strip shape, and the front side electrode and the back side electrode further have the stacking direction front side. or when viewed from the back side, comprising a plurality of detection portions which are formed by intersection, it is not good to adopt a configuration to detect the surface pressure distribution from the capacitance of the plurality of the detection unit.

  According to this configuration, the load on the detection unit can be detected from the capacitance of the detection unit. Further, a load distribution, that is, a surface pressure distribution can be detected from the capacitance distribution of the plurality of detection units. Moreover, both the front side electrode and the back side electrode are strip-shaped. And the detection part is arrange | positioned using the cross | intersection part of a front side electrode and a back side electrode. For this reason, the number of electrodes is reduced. In addition, the number of wires for detecting the capacitance from the detection unit is reduced.

  (3-1) Preferably, in the configuration of (3), the front electrodes are arranged in a plurality of rows, the back electrodes are arranged in a plurality of rows, a plurality of the front electrodes and a plurality of the back electrodes, Is preferably arranged substantially orthogonally as viewed from the front side or the back side in the stacking direction.

  According to this configuration, it is easy to disperse a plurality of detection units over the entire surface of the capacitive sensor. For this reason, the area of the part which can detect surface pressure which occupies the whole surface of a capacitance type sensor can be enlarged. In addition, it is possible to suppress variations in the arrangement of the detection unit on the entire surface of the capacitive sensor.

(4) Preferably, in the configuration of the above (3), the plurality of dielectric layers are in the order of small spring constants in the surface direction orthogonal to the stacking direction, and the direction from the stacking direction front side to the back side; but not good is better to adopt a configuration that is laminated so as to correspond to.

  Regardless of whether it is a dielectric (a stack of multiple dielectric layers) or a single dielectric layer, when a load is input, the load gradually increases as the load is transmitted from the front side to the back side. Dispersed in the surface direction.

  For this reason, for example, even when a load is input to a single detection unit, not only the capacitance of the detection unit but also the capacitances of other detection units adjacent to the detection unit change. May end up. In this case, when attention is paid to the detection unit to which the load is input, the amount of change in the capacitance is reduced by the amount that the load is distributed to the other detection units. For this reason, the apparent detection load becomes smaller than the actual load. Further, when attention is paid to the area where the load is input, the apparent detection area becomes larger than the actual load input area. As described above, when a plurality of dielectric layers are stacked, the sensitivity may decrease from the viewpoint of detection load and detection area.

  Therefore, the present inventor has focused on the spring constant in the surface direction of the dielectric layer. That is, the smaller the spring constant in the surface direction of the dielectric layer, the less the load is dispersed in the surface direction. On the contrary, the larger the spring constant in the surface direction of the dielectric layer, the easier the load is dispersed in the surface direction. Focusing on this characteristic, the inventor laminated the dielectric layers in the direction from the front side to the back side in the order of decreasing spring constant in the surface direction. That is, the dielectric layer having the smallest spring constant in the surface direction is disposed on the outermost side, and the dielectric layer having the largest spring constant in the surface direction is disposed on the outermost side.

  According to this configuration, when attention is paid to the detection unit to which a load is input in comparison with the case where the dielectric layer is laminated in the direction from the front side to the back side in the descending order of the spring constant in the surface direction, The load is difficult to disperse. For this reason, the apparent detection load is less likely to be smaller than the actual load. When attention is paid to the area where the load is input, the apparent detection area is less likely to be larger than the actual load input area. As described above, according to the present configuration, the sensitivity is hardly lowered from both the viewpoint of the detection load and the detection area.

(5) Preferably, in any configuration of the above (1) to (4), the front side electrode is printed on the surface of the dielectric, and the back side electrode is printed on the back surface of the dielectric. it is not good.

  According to this configuration, a flexible and thin capacitive sensor can be easily manufactured. In addition, components essential for load measurement, such as a plurality of dielectric layers, front-side electrodes, and back-side electrodes, can be integrated relatively easily. For this reason, the productivity of the capacitive sensor is high. Further, the positioning of the front side electrode and the back side electrode with respect to the dielectric is simple. Therefore, the detection unit can be accurately arranged at a desired position.

(6) Preferably, in the configuration of any one of the above (1) to (5), the configuration further includes a front side insulating layer disposed on the front side of the front side electrode and insulating the front side electrode from the outside. not good. According to this configuration, it is possible to suppress conduction between the front electrode and a person or a member outside the capacitive sensor.

  Note that the piezo film sensor of the robot of Patent Document 1 is covered from the front side with a soft silicone rubber layer. Silicone rubber has an insulating property. For this reason, the piezo film sensor of Patent Document 1 also includes a front-side insulating layer.

  However, the piezo film sensor is harder than the capacitive sensor of the present invention. For this reason, in the case of the piezo film sensor described in the document, it is necessary to increase the thickness of the silicone rubber layer in order to improve the flexibility of the sensor itself. Therefore, the sensitivity of the piezo film sensor is inevitably lowered.

  On the other hand, according to the capacitive sensor of the present invention, the dielectric, the front side electrode, and the back side electrode are all flexible. For this reason, even if the thickness of the front insulating layer is thin, the flexibility of the sensor itself can be easily ensured. Therefore, the sensitivity is not easily lowered.

(7) Moreover, in order to solve the said subject, the sensor attachment structure of the service robot of this invention of the structure in any one of said (1) thru | or (6) laminated | stacked on the surface of an exterior member and this exterior member It has a capacitive sensor, and you further comprising a contact portion in contact with humans.

  The contact portion includes an exterior member and a capacitive sensor. The capacitive sensor is laminated on the surface of the exterior member. For this reason, compared with the case where a capacitance type sensor is embed | buried inside the exterior member, a sensitivity does not fall easily. Further, the capacitance type sensor includes an elastomer dielectric, and front and back electrodes mainly composed of elastomer. For this reason, the capacitive sensor is more flexible than the piezo film sensor. Therefore, the contact portion can obtain a soft exterior. In addition, a human who touches the service robot, that is, a capacitive sensor, can obtain a soft tactile sensation.

(8) Preferably, in the configuration of (7), the maximum value of the spring constant in the stacking direction of the plurality of dielectric layers is smaller than the spring constant of the exterior member in the stacking direction. not good.

  According to this configuration, when a load is input, all the dielectric layers can be compressed in preference to the exterior member. For this reason, compared with the case where the exterior member is deformed in preference to the dielectric layer, the sensitivity of the capacitive sensor is increased.

(9) In the configuration of the above (7) or (8), wherein the contact portion is not good is better to adopt a configuration that is disposed on the arm portion lift in one's arms humans. According to this configuration, since the capacitive sensor is arranged on the surface of the exterior member, it is possible to detect with high sensitivity the load received from the person who is picked up. In addition, a human being held up can obtain a soft tactile sensation from a contact portion, that is, a capacitive sensor.

  Further, when the person is lifted by the arm, the weight is concentrated, so that the load applied to the contact portion is relatively large. Even in this case, the load can be detected with high sensitivity because the measurement range of the load of the capacitive sensor is wide.

(10) Preferably, in the construction of the above-mentioned (7) to (9), wherein the contact portion, the mutual arrangement of humans is operated through tactile when touching the contact part is not good.

  The load input to the capacitive sensor when a human touches is relatively small. Even in this case, the load can be detected with high sensitivity because the measurement range of the load of the capacitive sensor is wide.

  In particular, when this configuration and the configuration (9) are combined, a large “lifting load” and a small “contact load” are input to the capacitive sensor. Even in this case, the measurement range of the load of the capacitive sensor is wide from the low load region A to the high load region B as shown in FIG. For this reason, a load can be detected with high sensitivity. In addition, the number of sensors arranged is reduced as compared with the case where the sensor dedicated to the low load area A and the sensor dedicated to the high load area B are separately arranged. In addition, the mechanical configuration and electrical configuration of the service robot are simplified.

  According to the present invention, it is possible to provide a capacitive sensor that is flexible and has a wide load measurement range. Further, according to the present invention, it is possible to provide a sensor mounting structure that can achieve both the softness of the exterior of the service robot and the high sensitivity of the sensor.

It is a schematic diagram which shows the relationship between the load of an electrostatic capacitance type sensor of this invention, and an electrostatic capacitance. It is a perspective view of the robot for care which has the sensor attachment structure of one embodiment of the present invention. It is a fragmentary sectional perspective view of the sensor attachment structure. FIG. 4 is a development view in the IV-IV direction of FIG. 3. FIG. 5 is a cross-sectional view in the VV direction of FIG. 4. It is a schematic diagram of the dielectric material of FIG. FIG. 7 is a schematic diagram when a load is applied to a dielectric disposed upside down in the radial direction with respect to FIG. 6. It is a schematic diagram when a load is applied to the dielectric of FIG.

  Hereinafter, embodiments of the sensor mounting structure of the present invention will be described. In addition, the following description serves as description about embodiment of the electrostatic capacitance type sensor of this invention.

[Sensor mounting structure layout]
First, the arrangement of the sensor mounting structure of this embodiment will be described. FIG. 2 is a perspective view of a nursing robot having the sensor mounting structure of the present embodiment. As shown in FIG. 2, the nursing robot 9 includes two arm portions 90. The care robot 9 is included in the service robot of the present invention. The care robot 9 can hold up the care receiver 91 using only the two arms 90.

  Each of the two arm portions 90 includes a forearm portion 900 and an upper arm portion 901. The forearm 900 and the upper arm 901 are driven by a drive mechanism (not shown). The sensor mounting structure 2 is disposed on the forearm portion 900 and the upper arm portion 901.

[Configuration of sensor mounting structure]
Next, the configuration of the sensor mounting structure 2 will be described. The configuration of the four sensor mounting structures 2 is the same. Therefore, the configuration of the sensor mounting structure 2 of the forearm 900 of the left arm 90 will be described as a representative of these four sensor mounting structures 2.

  FIG. 3 shows a partial cross-sectional perspective view of the sensor mounting structure of the present embodiment. FIG. 4 shows a developed view in the IV-IV direction of FIG. FIG. 5 shows a cross-sectional view in the VV direction of FIG. For convenience of explanation, the front side electrodes 01X to 12X and the back side electrodes 01Y to 12Y are hatched in FIG. 3, and the detection units A0101 to A1212 are hatched in FIG. Moreover, in FIG. 4, back side electrode 01Y-12Y is shown with a thin line.

  In addition, in the symbol “AOOΔΔ” of the detection unit, the upper two digits “OO” correspond to the front side electrodes 01X to 12X. The last two digits “ΔΔ” correspond to the backside electrodes 01Y to 12Y. Moreover, the contact part 3 shown in FIGS. 3-5 is a part of the actual contact part 3 extracted. For this reason, actually, more front side electrodes 01X to 12X than those shown in FIGS. 3 to 5 are arranged in parallel in the axial direction. Also, more detectors A0101 to A1212 are arranged than shown in FIGS.

  As shown in FIGS. 3 to 5, the sensor mounting structure 2 includes a contact portion 3. The contact portion 3 includes an exterior member 4 and a capacitive sensor 5. The exterior member 4 is made of an elastomer and has an insulating property. The capacitive sensor 5 is disposed on the outer peripheral surface of the exterior member 4. The capacitive sensor 5 includes a dielectric 50, front side electrodes 01X to 12X, back side electrodes 01Y to 12Y, detection units A0101 to A1212, and a front side insulating layer 51.

  The dielectric 50 includes a front side dielectric layer 500 and a back side dielectric layer 501. The front-side dielectric layer 500 and the back-side dielectric layer 501 are included in the dielectric layer of the present invention. The front-side dielectric layer 500 is laminated on the front side (radially outer side) of the back-side dielectric layer 501. The front-side dielectric layer 500 is a urethane foam (trade name: EFF, manufactured by Inoac Corporation) and has a sheet shape. The 25% compressive load of the front-side dielectric layer 500 is 0.0024 MPa. The back side dielectric layer 501 is a urethane foam (trade name: PORON (registered trademark) SR-S-24P, manufactured by Roger Sinoac Co., Ltd.) and has a sheet shape. The 25% compressive load of the back side dielectric layer 501 is 0.008 MPa. Thus, the front-side dielectric layer 500 has a 25% compressive load smaller than the back-side dielectric layer 501. For this reason, the front-side dielectric layer 500 has a smaller spring constant in the stacking direction (radial direction) than the back-side dielectric layer 501. In addition, the front-side dielectric layer 500 has a smaller spring constant in the surface direction (circumferential direction and axial direction) than the back-side dielectric layer 501.

  A total of twelve front side electrodes 01 </ b> X to 12 </ b> X are disposed on the outer peripheral surface of the front side dielectric layer 500. The front-side electrodes 01X to 12X are each formed including acrylic rubber and conductive carbon black. The front side electrodes 01X to 12X each have a strip shape. The front side electrodes 01X to 12X each extend in the circumferential direction. The front-side electrodes 01X to 12X are arranged in the axial direction so as to be spaced apart from each other at predetermined intervals and to be substantially parallel to each other. The front side electrodes 01X to 12X are respectively connected to a calculation unit (not shown) via a front side wiring (not shown) and a front side wiring connector (not shown). The front side wiring is also arranged on the outer peripheral surface of the front side dielectric layer 500, similarly to the front side electrodes 01X to 12X. The front side wiring is formed including urethane rubber and silver powder.

  The front-side insulating layer 51 is disposed on the outer peripheral surface of the front-side dielectric layer 500. The front insulating layer 51 is formed including acrylic rubber. The front insulating layer 51 has a sheet shape. The front-side insulating layer 51 covers the front-side dielectric layer 500, the front-side electrodes 01X to 12X, and the front-side wiring from above.

  A total of twelve back-side electrodes 01Y to 12Y are arranged on the inner peripheral surface of the back-side dielectric layer 501. The back-side electrodes 01Y to 12Y are each formed including acrylic rubber and conductive carbon black. The back side electrodes 01Y to 12Y each have a strip shape. The back-side electrodes 01Y to 12Y each extend in the axial direction. The back-side electrodes 01Y to 12Y are arranged in the circumferential direction so as to be substantially parallel to each other with a predetermined interval. The back-side electrodes 01Y to 12Y are respectively connected to the arithmetic unit via a back-side wiring (not shown) and a back-side wiring connector (not shown). The back side wiring is also disposed on the inner peripheral surface of the back side dielectric layer 501 in the same manner as the back side electrodes 01Y to 12Y. The back side wiring is formed including urethane rubber and silver powder.

  As shown by hatching in FIG. 4, the detectors A0101 to A1212 are arranged at portions (overlapping portions) where the front side electrodes 01X to 12X and the back side electrodes 01Y to 12Y intersect when viewed from the radially outer side or the inner side. Has been. The detectors A0101 to A1212 are arranged at substantially equal intervals over substantially the entire surface of the capacitive sensor 5. Each of the detection units A0101 to A1212 includes a part of the front side electrodes 01X to 12X, a part of the back side electrodes 01Y to 12Y, and a part of the dielectric 50.

  The arithmetic unit includes a power supply circuit, a CPU (Central Processing Unit), a RAM (Random Access Memory), and a ROM (Read Only Memory). The computing unit is electrically connected to the front side wiring connector and the back side wiring connector.

[Method for manufacturing sensor mounting structure]
Next, the manufacturing method of the sensor mounting structure 2 of this embodiment is demonstrated. The manufacturing method of the sensor mounting structure 2 of this embodiment has a sensor manufacturing process and a sensor winding process. The sensor manufacturing process includes a dielectric layer lamination process, a paint preparation process, a layer front side electrode printing process, a front side wiring printing process, a front side insulating layer printing process, a back side electrode printing process, and a back side wiring printing process. doing.

  In the dielectric layer stacking step, the front-side dielectric layer 500 and the back-side dielectric layer 501 are stacked by bonding. That is, the dielectric 50 is produced.

  In the paint preparation step, an electrode paint, a wiring paint, and an insulating layer paint are prepared. The electrode paint is prepared by the following procedure. First, 100 parts by mass of a polymer (acrylic rubber, trade name: Nipol (registered trademark) AR51, manufactured by Nippon Zeon Co., Ltd.), a vulcanization aid (stearic acid, trade name: Lunac (registered trademark) S30, manufactured by Kao Corporation) 00 parts by mass, vulcanization accelerator (zinc dimethyldithiocarbamate, trade name: Noxeller (registered trademark) PZ, manufactured by Ouchi Shinsei Chemical Co., Ltd.) 2.50 parts by mass, vulcanization accelerator (ferric dimethyldithiocarbamate, commodity Name: Noxeller TTFE (manufactured by Ouchi Shinsei Chemical Co., Ltd.) 0.50 part by mass is weighed and rubber is kneaded using a roll. Then, a rubber compound is prepared. Subsequently, the prepared rubber compound is immersed in 1500 parts by mass of an organic solvent (methyl ethyl ketone, Sankyo Chemical Co., Ltd.), the organic solvent is stirred, and a solution in which the rubber compound is uniformly dissolved in the organic solvent is obtained. Then, 22.86 parts by mass of conductive carbon black (Ketjen Black, trade name: EC300J, manufactured by Lion Corporation) is added to the solution. Then, a MEK (methyl ethyl ketone) solution having a solid content of about 7.8% by mass is obtained. Then, the MEK solution is milled to improve the dispersibility of the conductive carbon black in the MEK solution. Specifically, the MEK solution is put into a dyno mill rotating at 3200 rpm, and the MEK solution is circulated about 40 times. Thereafter, 686.7 parts by mass of a printing solvent (diethylene glycol monobutyl ether acetate, manufactured by Sankyo Chemical Co., Ltd.) is added to the milled MEK solution. Then, the MEK solution to which the printing solvent is added is transferred to a container having a wide mouth in order to widen the area in contact with the atmosphere. Then, the MEK solution is allowed to stand for about one day with occasional stirring to sufficiently evaporate MEK having a low boiling point. In this way, an electrode paint is prepared. The boiling point of the printing solvent is 200 ° C. or higher. For this reason, the volatilization of the printing solvent is negligible.

  The wiring paint is prepared by the following procedure. First, 333 parts by mass of polymer (polyurethane dissolved in MEK / toluene / isopropyl alcohol, trade name: NIPPOLAN (registered trademark) 5230, manufactured by Nippon Polyurethane Industry Co., Ltd.) (the solid content of the polymer is 30% by mass, so 333 mass of polymer) Part corresponds to 100 parts by mass of polyurethane), 10 μm flaky silver particles (trade name: FA-D-4, manufactured by DOWA Electronics) 400 parts by mass, 1 μm spherical silver particles (trade names: AG2-1C, DOWA) 400 parts by mass of Electronics Co., Ltd.) and 150 parts by mass of a printing solvent (butyl carbitol, Sankyo Chemical Co., Ltd.) are weighed and stirred to homogenize. Then, the solution after stirring is transferred to a container having a wide mouth in order to widen the area in contact with the atmosphere. Then, the solution is allowed to stand for about a day with occasional stirring to sufficiently evaporate MEK, toluene and isopropyl alcohol having a low boiling point. In this way, a wiring paint is prepared.

  The insulating layer paint is prepared by the following procedure. First, 100 parts by mass of a polymer (acrylic rubber, trade name: Nipol AR51, manufactured by Nippon Zeon), vulcanization aid (stearic acid, trade name: Lunac S30, manufactured by Kao Corporation), 1.00 parts by weight, vulcanization accelerator (Zinc dimethyldithiocarbamate, trade name: Noxeller PZ, manufactured by Ouchi Shinsei Chemical) 2.50 parts by mass, vulcanization accelerator (Ferric dimethyldithiocarbamate, trade name: Noxeller TTFE, manufactured by Ouchi Shinsei Chemical) 0.50 part by mass is weighed, and rubber kneading is performed using a roll. Then, a rubber compound is prepared. Subsequently, the prepared rubber compound is immersed in 300 parts by mass of a printing solvent (ethylene glycol monobutyl ether acetate, manufactured by Daicel Chemical Industries, Ltd.), and stirred to make it uniform. In this way, an insulating layer paint is prepared.

  In the front side electrode printing step, the electrode coating material prepared in the coating material preparation step is printed on the surface of the front side dielectric layer 500 using a screen printer. That is, the front-side electrodes 01X to 12X are stacked on the surface of the front-side dielectric layer 500. Thereafter, the front side electrodes 01X to 12X are heated to vulcanize the polymer.

  In the front-side wiring printing step, the wiring paint prepared in the paint-preparing step is printed on the surface of the front-side dielectric layer 500 by using a screen printer as in the front-side electrode printing step. That is, the front side wiring is laminated on the surface of the front side dielectric layer 500. Thereafter, the front side wiring is dried.

  In the front-side insulating layer printing step, the insulating layer paint prepared in the paint-preparing step is applied to the surface of the front-side dielectric layer 500, the front-side electrodes 01X to 12X, and the front-side wiring using a screen printer, as in the front-side electrode printing step. Print. That is, the front-side insulating layer 51 is laminated on the surface of the front-side dielectric layer 500, the front-side electrodes 01X to 12X, and the front-side wiring. Thereafter, the front-side insulating layer 51 is heated to vulcanize the polymer.

  In the back side electrode printing step, the electrode coating material prepared in the coating material preparation step is printed on the back surface of the back side dielectric layer 501 by using a screen printer as in the case of the front side electrode printing step. That is, the back-side electrodes 01Y to 12Y are stacked on the back surface of the back-side dielectric layer 501. Thereafter, the back electrodes 01Y to 12Y are heated to vulcanize the polymer.

  In the back side wiring printing step, the wiring paint prepared in the coating material preparation step is printed on the back surface of the back side dielectric layer 501 using a screen printer as in the front side wiring printing step. That is, the back side wiring is laminated on the back side of the back side dielectric layer 501. Thereafter, the back side wiring is dried. In this way, the capacitive sensor 5 is manufactured.

  In the sensor winding process, the manufactured capacitive sensor 5 is attached to the exterior member 4. The manufactured capacitive sensor 5 is a thin and flexible sheet. The sheet-like capacitive sensor 5 is wound around the outer peripheral surface of the exterior member 4 and attached to complete the sensor mounting structure 2 of the present embodiment.

[Motion of sensor mounting structure]
Next, the movement of the sensor mounting structure 2 of this embodiment will be described. The power supply circuit of the calculation unit of the capacitive sensor 5 applies voltages to the detection units A0101 to A1212 in order in a scanning manner. In the ROM, a map indicating the correspondence between the capacitance and the load in the detection units A0101 to A1212 is stored in advance. The RAM temporarily stores an amount of electricity related to the capacitance input from the front-side wiring connector and the back-side wiring connector. The CPU calculates the capacitance of each of the detection units A0101 to A1212 from the amount of electricity stored in the RAM. And the load of each detection part A0101-A1212, ie, the surface pressure distribution in the electrostatic capacitance type sensor 5, is calculated from an electrostatic capacitance.

  As shown in FIG. 2, when the care robot 9 lifts the care recipient 91, the surface pressure distribution is constantly sampled. Here, when the load is concentrated on the specific detection units A0101 to A1212 (for example, when the load is equal to or greater than the threshold stored in the ROM), the care receiver 91 is covered by the detection units A0101 to A1212. The reaction force will be great.

  In such a case, it is necessary to distribute the concentration of the load in order to reduce the discomfort of the care recipient 91. Therefore, the caregiver operates the arm 90 that is the driving target as if it were a controller. Specifically, the caregiver presses the forearm 900 in the direction in which it is desired to operate. At this time, the caregiver touches the capacitive sensor 5. The calculation unit determines the amount of movement of the forearm portion 900 from the time that the caregiver is touching the capacitive sensor 5. Further, the calculation unit determines the moving speed of the forearm portion 900 from the load input when the caregiver touches it. In addition, the calculation unit determines the moving direction of the forearm unit 900 from the positions (coordinates) of the detection units A0101 to A1212 touched by the caregiver. Thus, when the caregiver touches the forearm portion 900, the drive mechanism is driven and the forearm portion 900 is moved.

[Function and effect]
Next, the effect of the sensor attachment structure 2 of this embodiment is demonstrated. According to the capacitive sensor 5 of the present embodiment, the front-side electrodes 01X to 12X and the back-side electrodes 01Y to 12Y are both strip-shaped. And detection part A0101-A1212 is arrange | positioned using the cross | intersection part of front side electrode 01X-12X and back side electrode 01Y-12Y. For this reason, the number of electrodes is reduced. In addition, the number of wirings is reduced. That is, a total of 144 detection units A0101 to A1212 are arranged. Here, if an electrode is arranged for each of the detection units A0101 to A1212, 144 front-side electrodes and 144 back-side electrodes are required. On the other hand, according to the capacitive sensor 5 of the present embodiment, a total of 24 front-side electrodes 01X to 12X and back-side electrodes 01Y to 12Y (= 12) are secured in order to secure 144 detection units A0101 to A1212. Book + 12)). For this reason, the number of electrodes is reduced.

  Further, the front side electrodes 01X to 12X and the back side electrodes 01Y to 12Y are formed including acrylic rubber and conductive carbon black. For this reason, when a load is applied, the front-side electrodes 01X to 12X and the back-side electrodes 01Y to 12Y can expand and contract together with the dielectric 50 according to the load. Therefore, there is little risk that the expansion and contraction of the dielectric 50 is restricted by the front-side electrodes 01X to 12X or the back-side electrodes 01Y to 12Y.

  Moreover, the front side wiring and the back side wiring are formed including urethane rubber and silver powder. For this reason, according to the load, the front side wiring and the back side wiring can be expanded and contracted. Therefore, there is little risk that the expansion or contraction of the dielectric 50 is restricted by the front side wiring or the back side wiring.

  Further, according to the capacitive sensor 5 of the present embodiment, the detection units A0101 to A1212 are dispersed on the entire surface of the capacitive sensor 5. Therefore, the area of the portion where the load can be detected in the entire surface of the capacitive sensor 5 can be increased.

  Further, according to the capacitive sensor 5 of the present embodiment, the front side electrodes 01X to 12X, the front side wiring, the back side electrodes 01Y to 12Y, and the back side wiring are arranged on the dielectric 50 by the screen printing method. For this reason, it is possible to integrate the components essential for measuring the surface pressure relatively easily. Therefore, the productivity of the capacitive sensor 5 and thus the sensor mounting structure 2 is high.

  Further, the front-side electrodes 01X to 12X and the back-side electrodes 01Y to 12Y are directly printed on the dielectric 50. For this reason, positioning with front side electrode 01X-12X and back side electrode 01Y-12Y is easy. Therefore, the detection units A0101 to A1212 can be accurately arranged at desired positions.

  Moreover, the front-side insulating layer 51 is disposed in the capacitive sensor 5 of the present embodiment. For this reason, it can suppress that the cared person 91 and the caregiver touch the front side electrodes 01X to 12X. As shown in FIG. 3, the back surfaces of the back side electrodes 01 </ b> Y to 12 </ b> Y are in contact with the insulating exterior member 4. For this reason, the insulation of the back side electrodes 01Y to 12Y is secured.

  The capacitive sensor 5 of the present embodiment includes an elastomer dielectric 50, and front-side electrodes 01X to 12X and back-side electrodes 01Y to 12Y mainly composed of elastomer. For this reason, it is more flexible than a piezo film sensor.

  Further, according to the capacitive sensor 5 of the present embodiment, when a plurality of conventional capacitive sensors (a) (front side electrode-single layer dielectric layer-back side electrode) are laminated, or (b) Compared with the case where a plurality of capacitive sensors 5 of the present embodiment are stacked, the number of electrodes arranged is reduced. Further, since the number of electrodes arranged is small, the electrical configuration is simplified.

  In the cases (a) and (b), the input load is transmitted from the front-side capacitive sensor to the back-side capacitive sensor. For this reason, the load detection timing is shifted between the front-side capacitive sensor and the back-side capacitive sensor. Therefore, it is necessary to synchronize the detection data of each capacitive sensor. On the other hand, in the case of the capacitive sensor 5 of the present embodiment, since it is arranged in a single layer, it is not necessary to synchronize the detection data. Also in this respect, the electrical configuration is simplified.

  Further, the dielectric 50 of the capacitive sensor 5 of the present embodiment is formed by laminating the front side dielectric layer 500 having a small 25% compressive load and the back side dielectric layer 501 having a large 25% compressive load. Has been. The front-side dielectric layer 500 mainly functions for load detection in the low-load region, and the back-side dielectric layer 501 mainly functions for load detection in the high-load region. For this reason, as compared with the case where only the front-side dielectric layer 500 having a small 25% compressive load is arranged alone, the load can be detected not only in the low load region but also in the high load region. Therefore, according to the capacitive sensor 5 of the present embodiment, the load measurement range is widened. In addition, the sensitivity in the low load region can be increased as compared with the case where only the back-side dielectric layer 501 having a high 25% compressive load is disposed alone.

  Further, the 25% compressive load of the front-side dielectric layer 500 and the back-side dielectric layer 501 are both included in the range of 0.001 MPa to 0.01 MPa. For this reason, it is flexible and there is no sense of incongruity in the touch feeling.

  Further, according to the capacitive sensor 5 of the present embodiment, the front-side dielectric layer 500 and the back-side dielectric layer 501 are laminated from the radially outer side to the radially inner side in order of increasing 25% compression load. That is, the front-side dielectric layer 500 having a small 25% compressive load is disposed on the radially outer side, and the back-side dielectric layer 501 having a large 25% compressive load is disposed on the radially inner side.

  Hereinafter, the effect of the dielectric layer arrangement pattern will be described with reference to schematic views. In the following description, the detection units A0605 to A0607 adjacent in the circumferential direction are exemplified, but the same applies to the detection units adjacent in the axial direction.

  FIG. 6 is a schematic diagram of the dielectric shown in FIG. The front-side dielectric layer 500 includes circumferential springs 500a and 500b and radial springs 500A to 500C. The back-side dielectric layer 501 includes circumferential springs 501a and 501b and radial springs 501A to 501C.

  Here, the circumferential spring constants of the circumferential springs 500a and 500b of the front-side dielectric layer 500 are smaller than the circumferential spring constants of the circumferential springs 501a and 501b of the back-side dielectric layer 501. The radial spring constants of the radial springs 500A to 500C of the front side dielectric layer 500 are smaller than the radial spring constants of the radial springs 501A to 501C of the back side dielectric layer 501.

  FIG. 7 shows a schematic diagram when a load is applied to a dielectric disposed upside down in the radial direction with respect to FIG. In addition, the form of the schematic diagram shown in FIG. 7 is included in the capacitive sensor of the present invention. As indicated by the white arrow in FIG. 7, when a load is applied to the detection portion A0606, the radial spring 501B of the back side dielectric layer 501 (which is disposed on the front side in FIG. 7) is compressed. Here, the circumferential spring constants of the circumferential springs 501a and 501b of the back-side dielectric layer 501 are relatively large. For this reason, when a load is applied to the radial spring 501B, the load is easily dispersed to the radial springs 501A and 501C via the circumferential springs 501a and 501b. Therefore, when a load is applied to the radial spring 501B, the radial springs 501A and 501C are easily compressed. As described above, when the back side dielectric layer 501 is arranged on the radially outer side and the front side dielectric layer 500 is arranged on the radially inner side, the detection units A0605 and A0607 into which the load is not inputted together with the detection unit A0606 into which the load is inputted. It becomes easy to deform. That is, the capacitance of not only the detection unit A0606 but also the detection units A0605 and A0607 is likely to change.

  Therefore, when attention is paid to the number of detection units to which a load is input, the number of detection units 1 to which a load is actually input is likely to be mistaken as an apparent number of detection units 3. That is, when a load is transmitted from the front-side dielectric layer 500 to the back-side dielectric layer 501, the load transmission area is likely to change. Further, when attention is paid to the detection unit A0606 to which the load is input, the load is easily dispersed to the other detection units A0605 and A0607, and thus the apparent detection load becomes smaller than the actual load. As described above, when the back side dielectric layer 501 having a large 25% compressive load is arranged radially outward and the front side dielectric layer 500 having a small 25% compressive load is arranged radially inside, the detection load is also reduced from the viewpoint of the detection area. From the viewpoint, the sensitivity is likely to decrease.

  FIG. 8 shows a schematic diagram when a load is applied to the dielectric of FIG. As indicated by the white arrow in FIG. 8, when a load is applied to the detection unit A0606, the radial spring 500B of the front-side dielectric layer 500 is compressed. Here, the circumferential spring constants of the circumferential springs 500a and 500b of the front-side dielectric layer 500 are relatively small. For this reason, even if a load is applied to the radial spring 500B, it is difficult for the load to be distributed to the radial springs 500A and 500C via the circumferential springs 500a and 500b. Therefore, even if a load is applied to the radial spring 500B, the radial springs 500A and 500C are not easily compressed. In this way, by arranging the front-side dielectric layer 500 on the radially outer side and the back-side dielectric layer 501 on the radially inner side, it is possible to suppress the deformation of the detection units A0605 and A0607 to which no load is input. it can. That is, it can suppress that the electrostatic capacitance of detection part A0605 and A0607 changes.

  Therefore, when paying attention to the number of detection units to which a load is input, the number of apparent detection units is less likely to increase compared to the number of detection units 1 to which a load is actually input. That is, when a load is transmitted from the front-side dielectric layer 500 to the back-side dielectric layer 501, the load transmission area hardly changes. Therefore, the sensitivity is not easily lowered.

  Further, when attention is paid to the detection unit A0606 to which a load is input, the load is difficult to be distributed to the other detection units A0605 and A0607, so that the apparent detection load is less likely to be smaller than the actual load. That is, the sensitivity is not easily lowered.

  In this way, by disposing the front side dielectric layer 500 having a small 25% compressive load on the radially outer side and the back side dielectric layer 501 having a large 25% compressive load on the radially inner side, detection can be performed from the viewpoint of detection area. From the viewpoint of load, the sensitivity is hardly lowered.

  Further, according to the sensor mounting structure 2 of the present embodiment, the capacitive sensor 5 is laminated on the outer peripheral surface of the exterior member 4. For this reason, compared with the case where the electrostatic capacitance type sensor 5 is embed | buried under the exterior member 4, a sensitivity does not fall easily. Further, the capacitive sensor 5 is more flexible than the piezo film sensor. Therefore, the contact part 3 can obtain a soft exterior.

  Further, according to the sensor mounting structure 2 of the present embodiment, the radial spring constant of the back side dielectric layer 501 is smaller than the radial spring constant of the exterior member 4. For this reason, when a load is input, the front-side dielectric layer 500 and the back-side dielectric layer 501 can be compressed in preference to the exterior member 4. Therefore, the sensitivity of the capacitive sensor 5 is higher than when the exterior member 4 is deformed in preference to the front-side dielectric layer 500 and the back-side dielectric layer 501.

  Further, according to the sensor mounting structure 2 of the present embodiment, the capacitive sensor 5 is arranged on the outer peripheral surface of the exterior member 4. For this reason, the load received from the care receiver 91 held up can be detected with high sensitivity. In addition, the cared person 91 held up can obtain a soft tactile sensation from the contact portion 3, that is, the capacitive sensor 5.

  Further, when the care receiver 91 is lifted by the arm 90, the load applied to the contact portion 3 is relatively large. Even in this case, since the load measuring range of the capacitive sensor 5 is wide, the load can be detected with high sensitivity. On the other hand, when the caregiver touches for operation, the load input to the capacitive sensor 5 is relatively small. Even in this case, since the load measuring range of the capacitive sensor 5 is wide, the load can be detected with high sensitivity. Further, the number of sensors arranged is reduced as compared with the case where the sensor dedicated to the low load area and the sensor dedicated to the high load area are separately arranged. In addition, the mechanical configuration and electrical configuration of the care robot 9 are simplified.

[Others]
The embodiment of the sensor mounting structure 2 of the present invention has been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  For example, the arrangement number, the crossing angle, and the extending direction of the front side electrodes 01X to 12X and the back side electrodes 01Y to 12Y are not particularly limited. Further, the interval between the adjacent front side electrodes 01X to 12X and the interval between the back side electrodes 01Y to 12Y are not particularly limited. Moreover, you may print antioxidant so that front side wiring and back side wiring may be covered. This can suppress the oxidation of silver in the wiring. Further, a back-side insulating layer may be disposed between the exterior member 4 and the back-side electrodes 01Y to 12Y in the same manner as the front-side insulating layer 51.

  Further, the number of dielectric layers stacked in the dielectric 50 is not particularly limited. Three or more dielectric layers may be laminated. Moreover, the thickness of the front side dielectric layer 500 and the back side dielectric layer 501 is not specifically limited. For example, it is desirable that the thickness be 1 μm or more and 3000 μm or less from the viewpoint of reducing the thickness of the capacitance type sensor 5 and improving the sensitivity by increasing the capacitance. 50 μm or more and 500 μm or less is more preferable.

  Further, two or more capacitive sensors 5 may be laminated on the outer peripheral surface of the exterior member 4. Even in this case, the number of electrodes arranged is reduced as compared with the case where two or more capacitive sensors having a conventional structure of (front side electrode-single layer dielectric layer-back side electrode) are stacked. Also, the electrical configuration is simplified.

  Further, the arrangement location of the sensor mounting structure 2 in the nursing robot 9 is not particularly limited. It may be placed on the chest, back, abdomen, head, shoulders, etc. In the above embodiment, the capacitive sensor 5 is used as a tactile sensor. However, for example, it may be used as a collision sensor that detects a collision of the nursing robot 9. Further, the capacitive sensor 5 may be used for other service robots such as a moving robot and a pet robot. In addition, the capacitance type sensor 5 is used as a fall sensor that is placed under the bed and detects a fall of the care recipient 91 from the bed, a seat sensor that is placed under the seat of the vehicle and detects the seating pressure distribution of the occupant, and the like. May be.

  Moreover, in the sensor manufacturing process of the manufacturing method of the sensor attachment structure 2, you may perform a process in order of a front side wiring printing process-> front side electrode printing process. Similarly, you may perform a process in order of a back side wiring printing process-> back side electrode printing process.

  Moreover, the printing method in a sensor manufacturing process is not specifically limited. In addition to screen printing, inkjet printing, flexographic printing, gravure printing, pad printing, lithography, dispenser printing, and the like may be used.

  Moreover, the elastomer which comprises the front side dielectric layer 500 and the back side dielectric layer 501 can be suitably selected from rubber | gum and a thermoplastic elastomer. The elastomer is not particularly limited. For example, from the viewpoint of increasing the capacitance, one having a high relative dielectric constant is desirable. For example, it is desirable that the relative dielectric constant at room temperature is 3 or more, and further 5 or more. For example, an elastomer having a polar functional group such as an ester group, a carboxyl group, a hydroxyl group, a halogen group, an amide group, a sulfone group, a urethane group, or a nitrile group, or an elastomer added with a polar low molecular weight compound having these polar functional groups Is preferably used. The elastomer may or may not be cross-linked. Moreover, what is necessary is just to adjust the measurement range of a sensitivity or a load according to a use by adjusting the Young's modulus of an elastomer, and a 25% compressive load. That is, the front-side dielectric layer 500 and the back-side dielectric layer 501 with various Young's modulus and 25% compression load can be selected according to the magnitude of the input load.

  When it is desired to reduce the lower limit of the load measurement range, it is preferable to use a foam as the dielectric layer elastomer. The reason is that since the foam has a small 25% compressive load, the dielectric layer is sufficiently deformed even when the input load is small. That is, it is possible to reliably detect the surface pressure and load of the measurement object (human, object, etc.).

  Examples of suitable elastomers include silicone rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, and urethane rubber.

  Examples of elastomers suitable for the front electrodes 01X to 12X and the back electrodes 01Y to 12Y include silicone rubber, ethylene-propylene copolymer rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, Examples include epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, and urethane rubber.

  Moreover, in the front side electrodes 01X to 12X and the back side electrodes 01Y to 12Y, the shape of the conductive filler blended in the elastomer is not particularly limited, such as a spherical shape, a needle shape, or a prism shape. For example, the aspect ratio (the ratio of the long side to the short side) of the conductive filler is preferably 1 or more. For example, when a needle-like conductive filler having a relatively large aspect ratio is used, a three-dimensional conductive network can be easily formed, and high conductivity can be realized with a small amount. In addition, it is possible to suppress a change in conductivity when the front side electrodes 01X to 12X and the back side electrodes 01Y to 12Y expand and contract.

  Moreover, when selecting a conductive filler, it is good to consider an average particle diameter, compatibility with an elastomer, etc. For example, when a spherical conductive filler is employed, the average particle diameter (primary particles) of the conductive filler is desirably 0.01 μm or more and 0.5 μm or less. When the thickness is less than 0.01 μm, the cohesiveness is high, and it is difficult to uniformly disperse the electrode paint. Preferably it is 0.03 micrometer or more. On the other hand, when it exceeds 0.5 μm, it becomes difficult to form aggregates (secondary particles). Preferably it is 0.1 micrometer or less. The critical volume fraction (φc) in the percolation curve can be adjusted within a desired range by appropriately adjusting the combination of the conductive filler and the elastomer, the average particle diameter of the conductive filler, and the like.

  Moreover, in order to express desired electroconductivity, it is desirable that the conductive filler is blended at a ratio equal to or higher than the critical volume fraction (φc) in the percolation curve. On the other hand, when the filling rate of the conductive filler exceeds 30 vol%, mixing with the elastomer becomes difficult, and molding processability is deteriorated. In addition, the stretchability of the front side electrodes 01X to 12X and the back side electrodes 01Y to 12Y is lowered. For this reason, it is desirable that it is 30 vol% or less. In addition, from the viewpoint of securing the stretchability of the front side electrodes 01X to 12X and the back side electrodes 01Y to 12Y, it is desirable that a relatively small amount of a conductive filler is blended to express high conductivity. Therefore, it is desirable that the filling rate of the conductive filler is 25 vol% or less when the volume of the front side electrodes 01X to 12X and the back side electrodes 01Y to 12Y is 100 vol%. It is more preferable that it is 15 vol% or less.

  Further, the thicknesses of the front-side electrodes 01X to 12X and the back-side electrodes 01Y to 12Y are not particularly limited. In consideration of followability with respect to the dielectric 50, it is desirable that the thickness be 1 μm or more and 100 μm or less from the viewpoint of reducing the thickness of the capacitive sensor 5.

  The electrical resistances of the front side electrodes 01X to 12X and the back side electrodes 01Y to 12Y are preferably 100 kΩ or less in the radial direction, the circumferential direction, and the axial direction, and more preferably 10 kΩ or less.

  Moreover, in addition to the said elastomer and a conductive filler, various additives may be mix | blended with the front side electrodes 01X-12X and the back side electrodes 01Y-12Y. Examples of the additive include a crosslinking agent, a vulcanization accelerator, a vulcanization aid, an antiaging agent, a plasticizer, a softening agent, and a colorant.

  Moreover, the elastomer which comprises front side wiring and back side wiring may be the same as the elastomer used for the dielectric material 50, front side electrode 01X-12X, and back side electrode 01Y-12Y, and may differ. For example, silicone rubber, ethylene-propylene copolymer rubber, natural rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylic rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, etc. Is preferred.

  Moreover, the kind of electroconductive particle will not be specifically limited if the electroconductivity is high. For example, metal powder such as silver, copper, gold, or nickel may be employed. Moreover, in order to express desired conductivity, the filling rate of the conductive particles in the elastomer is desirably 20 vol% or more when the volume of the front wiring or the back wiring is 100 vol%. Moreover, in order to suppress the reduction | decrease in the elasticity of front side wiring and back side wiring, it is desirable that the filling rate of the electroconductive particle in an elastomer is 50 vol% or less.

  Examples of the material for forming the front side insulating layer 51 include acrylic rubber, urethane rubber, silicone rubber, ethylene propylene copolymer rubber, natural rubber, styrene-butadiene rubber, acrylonitrile butadiene rubber, epichlorohydrin rubber, chlorosulfonated polyethylene, A sheet of chlorinated polyethylene rubber or the like may be used. Further, it is preferable that the thickness of the front insulating layer 51 is thin. The thinner one can improve the sensitivity of the capacitive sensor 5. Preferably, the thickness is 10 μm or less.

2: sensor mounting structure, 3: contact portion, 4: exterior member, 5: capacitive sensor, 9: nursing robot (service robot).
50: Dielectric, 51: Front insulating layer, 90: Arm, 91: Care recipient.
500: front side dielectric layer (dielectric layer), 500a: circumferential spring, 500b: circumferential spring, 500A to 500C: radial spring, 501: back side dielectric layer (dielectric layer), 501a: circumferential spring, 501b: circumferential direction Spring, 501A to 501C: radial spring, 900: forearm, 901: upper arm.
A: Low load region, B: High load region, a: Dielectric layer, b: Dielectric layer, 01X to 12X: Front side electrode, 01Y to 12Y: Back side electrode, A0101 to A1212: Detection unit.

Claims (8)

A dielectric made of an elastomer, in which a plurality of dielectric layers having different spring constants in the stacking direction are stacked;
A front electrode disposed on the front side of the dielectric and having an elastomer and a conductive filler filled in the elastomer;
A backside electrode disposed on the back side of the dielectric and having an elastomer and a conductive filler filled in the elastomer;
Equipped with a,
The front side electrode and the back side electrode are both strips,
Furthermore, the front side electrode and the back side electrode are provided with a plurality of detection units formed by intersecting when viewed from the front side or the back side in the stacking direction,
The plurality of dielectric layers are laminated so that the order of small spring constants in the plane direction perpendicular to the lamination direction corresponds to the direction from the front side to the back side of the lamination direction,
A capacitance-type sensor that detects a surface pressure distribution from a plurality of capacitances of the detection units .   2. The capacitive sensor according to claim 1, wherein a 25% compressive load of JIS K 6767 of the dielectric layer is 0.001 MPa or more and 0.01 MPa or less.   3. The capacitive sensor according to claim 1, wherein the front electrode is printed on the surface of the dielectric, and the back electrode is printed on the back of the dielectric.   The capacitive sensor according to any one of claims 1 to 3, further comprising a front-side insulating layer disposed on a front side of the front-side electrode and insulating the front-side electrode from the outside.   An exterior member;
  The capacitive sensor according to any one of claims 1 to 4, which is laminated on a surface of the exterior member;
A service robot sensor mounting structure having a contact portion that contacts a human.   The sensor mounting structure according to claim 5, wherein a maximum value of a spring constant of the plurality of dielectric layers in the stacking direction is smaller than a spring constant of the exterior member in the stacking direction.   The sensor attachment structure according to claim 5, wherein the contact portion is disposed on an arm portion that lifts a person.   The sensor attachment structure according to any one of claims 5 to 7, wherein the contact portion is operated via a tactile sensation when a human touches the contact portion.

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