JP6845710B2 - Cable-shaped pressure sensor and tactile sensor using it - Google Patents

Description

The present invention relates to a cable-shaped pressure sensor having piezoelectricity and a tactile sensor using the same.

Conventionally, a tactile sensor is attached to a woven fabric such as a glove worn on a human hand to detect the pressure applied to the woven fabric, or the tactile sensor is deformed to move the woven fabric (for example). , Patent Document 1). In this tactile sensor, electrode films are formed on both sides of a string-shaped piezoelectric material whose both opposite sides are flat, and the outsides of both electrode films are covered with insulating films, respectively, and the piezoelectric fibers are formed of warp threads and weft threads. It is formed into a woven cloth by alternately weaving like this. Since such a tactile sensor needs to bend along the surface of the object to be detected, it is required to have flexibility that allows it to be deformed in all directions. However, since the above-mentioned piezoelectric fiber is formed flat, there is a problem that it is easy to bend in the thickness direction but difficult to bend in the width direction.

Further, a coaxial cable type cable-shaped pressure sensor that easily bends in any direction around the axis has also been developed (see, for example, Patent Document 2). The cable-shaped pressure sensor described in Patent Document 2 has a configuration in which a flexible pressure-sensitive body is formed around a core electrode, and a flexible outer electrode is further formed around the flexible pressure-sensitive body. Then, by applying a high DC voltage between the core electrode and the flexible outer electrode, the flexible pressure sensitive body is polarized to impart piezoelectricity. By imparting piezoelectricity to the flexible pressure sensitive body, when pressure is applied to the cable-shaped pressure sensor, a voltage is induced between the core electrode and the flexible outer electrode, and this voltage is applied to the cable-shaped pressure sensor. The applied pressure can be detected.

JP-A-2002-203996 Japanese Unexamined Patent Publication No. 2008-151638

The woven fabric-like tactile sensor is required to have flexibility as described above, and also to have high elasticity and thin thickness. However, in the conventional cable-shaped pressure sensor described above, since the core electrode is made of a metal wire, there are restrictions on increasing the flexibility and reducing the diameter, and also the elasticity in the axial direction. poor. Therefore, the cable-shaped pressure sensor described above is not suitable for use in a woven fabric-shaped tactile sensor.

The present invention has been made to address the above-mentioned problems, and an object of the present invention is to provide a cable-shaped pressure sensor having excellent flexibility and elasticity and capable of reducing the diameter, and a tactile sensor using the same. Is. In the following description of each constituent requirement of the present invention, in order to facilitate understanding of the present invention, the reference numerals of the corresponding parts of the embodiments are described in parentheses, but the constituent requirements of the present invention are carried out. It should not be construed as limited to the configuration of the corresponding parts indicated by the code of the form.

In order to achieve the above-mentioned object, the structural feature of the cable-shaped pressure sensor (11, 31, 41, 51, 61) according to the present invention is a flexible elongated cylindrical piezoelectric body (12, 32, 42,62), the inner conductor layer (13,33,43,63) formed on the inner surface of the piezoelectric body, and the outer conductor layer (14,34,44,64) formed on the outer surface of the piezoelectric body. Bei example a cylindrical sensor wire (51a) made of the piezoelectric body, a flat strip of piezoelectric film (12a, 42a) is formed by wrapping a cylindrical, inner conductor layer (33, 43) is a piezoelectric It is composed of internal band-shaped layers (13a, 43a) formed on one surface side of the film and arranged so as to be located on the inner surface side when the piezoelectric film is wound in a cylindrical shape, and the inner band-shaped layer is one of the piezoelectric films. is formed in the widthwise central portion of the surface, the piezoelectric film is in the arc edge which is not internal strip layer is formed (12b, 42b) how to come into contact is formed in a cylindrical shape of the piezoelectric body.

In the cable-shaped pressure sensor according to the present invention, not a metal wire but an internal conductor layer formed along the inner surface of the piezoelectric body is located inside the cylindrical piezoelectric body. Therefore, the inner conductor layer can be formed thin, which makes it possible to increase the flexibility and elasticity of the cable-shaped pressure sensor and also to reduce the weight. Further, the inside of the inner conductor layer may be left as a space or may be filled with soft fibers or the like, but when the space is used, the outer diameter of the cable-shaped pressure sensor can be reduced by reducing the diameter of this portion. Can also be made smaller. Further, in order to improve the sensitivity of the cable-shaped pressure sensor, it is preferable that the piezoelectric body is easily deformed, but the cable-shaped pressure sensor according to the present invention has a diameter by leaving the inside as a space. Deformation in the direction is more likely to occur, which also improves sensitivity. In addition, by making the interior a space, it is possible to significantly reduce costs.

Materials constituting the piezoelectric material include polylactic acid, vinylidene fluoride, vinylidene cyanide, polyamide, vinylidene cyanide, polytetrafluoroethylene and their foams and polymers, their copolymers and their laminates. Further, a foam or the like can also be used. Further, as the material constituting the inner conductor layer and the outer conductor layer, various conductive materials such as metals such as copper, silver, platinum and aluminum and alloys thereof can be used, and when silver and aluminum are used. It is preferable to form a layer by vapor deposition. Further, as a material constituting the inner conductor layer and the outer conductor layer, a conductive polymer, a conductive paint, or the like can be used, which further increases the flexibility. When one sensor electric wire is used, the cable-shaped pressure sensor according to the present invention is configured only by the sensor electric wire.

In the cable-shaped pressure sensor according to the present invention, a cylindrical piezoelectric body and an internal conductor layer are formed by winding a flat band-shaped piezoelectric film having an internal band-shaped layer formed on one surface. By doing so, the formation of the piezoelectric body and the inner conductor layer becomes easy. Further, the outer diameter of the piezoelectric body constituting the cable-shaped pressure sensor can be arbitrarily set. The piezoelectric body in this case may be formed in a cylindrical shape by vertically overlapping both edges of the flat band-shaped piezoelectric film in the width direction, or the flat band-shaped piezoelectric film may be twisted and bent in a spiral shape. It may be formed in a cylindrical shape.

According to the present invention, it is possible to surely prevent the inner conductor layer from being exposed to the outer surface of the piezoelectric body, so that a good cable-shaped pressure sensor can be obtained. The edges of the piezoelectric films may overlap each other, or the end faces may be in contact with each other.

Other structural features of the cable-shaped pressure sensor (41) according to the present invention are an elongated cylindrical piezoelectric body (42) having flexibility and an internal conductor layer (43) formed on the inner surface of the piezoelectric body. When provided with a cylindrical sensor wire consisting an outer conductor layer formed on the outer surface of the piezoelectric body (44), pressure collector, and if the width direction of the edge of the flat belt of the piezoelectric film (42a) (42b) The inner conductor layer is formed in the central portion of one surface of the piezoelectric film excluding the edge in the width direction, and when the piezoelectric film is wound in a cylindrical shape. It is composed of an inner band-shaped layer (43a) arranged so as to be located on the inner surface side, and the outer conductor layer is formed in the central portion excluding the edge in the width direction of the other surface of the piezoelectric film, and the piezoelectric film has a cylindrical shape. It is composed of an outer band-shaped layer (44a) arranged so as to be located on the outer surface side when wound.

In the present invention, the sensor electric wire constituting the cable-shaped pressure sensor is formed in a cylindrical shape by winding a flat band-shaped piezoelectric film in which an inner band-shaped layer and an outer band-shaped layer are formed around the central portion in the width direction of both sides. ing. By doing so, the formation of the piezoelectric body, the inner conductor layer and the outer conductor layer becomes easy. In addition, the outer diameter of the sensor wire can be set arbitrarily. In the present invention, it is preferable that both edges of the piezoelectric film to be joined are fixed by adhesion or welding. The piezoelectric body in this case may be formed into a cylindrical shape by straightening both edges of the flat band-shaped piezoelectric film in the width direction and stacking them, or by twisting and bending the flat band-shaped piezoelectric film in a spiral shape. It may be formed in a cylindrical shape. Further, also in this case, the edges of the piezoelectric films may overlap each other, or the end faces may be in contact with each other.

Yet another structural feature of the cable-shaped pressure sensor (51) according to the present invention is that a plurality of sensor electric wires (51a) are twisted together to form a twisted yarn. According to the present invention, the twisting makes the cable-shaped pressure sensor more easily bent and expanded / contracted by an external force. Further, when the cable-shaped pressure sensor is bent, a large bending portion is generated, which generates a large output voltage, so that the sensitivity of the cable-shaped pressure sensor is improved. Further, by configuring the cable-shaped pressure sensor with a plurality of sensor wires, even if one of the sensor wires is broken, the other sensor wires can maintain the function as the cable-shaped pressure sensor.

Yet another structural feature of the cable-shaped pressure sensor according to the present invention is that the outer circumference of the outer conductor layer (64) is covered with an insulating sheath (65). According to the present invention, since the sensor electric wire composed of the piezoelectric body, the inner conductor layer and the outer conductor layer is protected by the insulating sheath, the sensor electric wire can be maintained in an appropriate state and can be prevented from being damaged. When the cable-shaped pressure sensor is composed of a plurality of sensor wires, the entire plurality of sensor wires may be coated with an insulating sheath, or the entire sensor wire may be coated with an insulating sheath. Good. As a material constituting the insulating sheath, a thermoplastic resin, a thermoplastic elastomer, a vulcanized rubber, or the like can be used.

Yet another structural feature of the cable-shaped pressure sensor according to the present invention is that the diameter of the sensor wire is set to 0.2 mm to 0.8 mm. According to the present invention, an ultrafine cable-shaped pressure sensor can be obtained.

A structural feature of the tactile sensor (10) according to the present invention is that a cable-shaped pressure sensor is assembled in a cloth shape. According to the present invention, it is possible to obtain a lightweight tactile sensor having excellent flexibility and elasticity. Further, the tactile sensor may be formed by weaving a cable-shaped pressure sensor as warp threads and weft threads into a woven fabric shape, or by knitting a cable-shaped pressure sensor into a knitted shape.

It is a perspective view which showed a part of the tactile sensor which concerns on 1st Embodiment of this invention. It is sectional drawing which showed the cable-shaped pressure sensor which constitutes a tactile sensor. It is a block diagram which showed the detection part provided in the robot. The state when pressure is applied to the tactile sensor is shown, (a) is a cross-sectional view before pressure is applied, and (b) is a cross-sectional view when pressure is applied. It is a top view which showed the piezoelectric film and the inner band-shaped layer used in the modification of 1st Embodiment. A cable-shaped pressure sensor constituting the tactile sensor according to the second embodiment of the present invention is shown, (a) is a side view, and (b) is a cross-sectional view. It is a side view which showed the sensor central part. A cable-shaped pressure sensor constituting the tactile sensor according to the third embodiment of the present invention is shown, (a) is a side view, and (b) is a cross-sectional view. It is sectional drawing which showed the piezoelectric film, the inner band-shaped layer and the outer band-shaped layer used in the third embodiment. A cable-shaped pressure sensor constituting the tactile sensor according to the fourth embodiment of the present invention is shown, (a) is a side view, and (b) is a cross-sectional view. It is sectional drawing which showed the cable-shaped pressure sensor which comprises the tactile sensor which concerns on 5th Embodiment.

(First Embodiment)
Hereinafter, the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a part of the tactile sensor 10 according to the present embodiment. The tactile sensor 10 is attached to, for example, a hand-shaped grip portion of a robot (not shown) for harvesting crops, and detects the pressure when the grip portion of the robot grips the crop. The grip portion is used to control the gripping force when gripping the agricultural product, and is formed in the shape of a glove covering the grip portion.

The tactile sensor 10 is manufactured by knitting a cable-shaped pressure sensor 11 (see FIG. 2) into a warp 11a and a weft 11b to form a woven fabric, and sewing the woven fabric into the shape of a glove. There is. As shown in FIG. 2, the cable-shaped pressure sensor 11 constituting the warp threads 11a and the weft threads 11b forms a thin inner conductor layer 13 on the inner peripheral surface of the cylindrical piezoelectric body 12, and the piezoelectric body 12 has a thin inner conductor layer 13. It is configured by forming a thin outer conductor layer 14 on the outer peripheral surface.

The piezoelectric body 12 is made of polyvinylidene fluoride (PVDF) and is composed of a flexible and stretchable ultrafine cylinder having an inner diameter of 0.15 mm to 0.60 mm, preferably 0.30 mm. The outer diameter is set to 0.25 mm to 0.65 mm, preferably 0.32 mm. The inner conductor layer 13 is made of a thin film made of silver, and is formed on the inner peripheral surface of the piezoelectric body 12 by thin film deposition. The thickness of the inner conductor layer 13 is about 0.5 μm to 2.0 μm, preferably about 0.5 μm. Like the inner conductor layer 13, the outer conductor layer 14 is formed on the outer peripheral surface of the piezoelectric body 12 by vapor deposition of silver. The thickness of the outer conductor layer 14 is substantially the same as the thickness of the inner conductor layer 13.

The piezoelectric body 12 is formed by, for example, a known drawing method. In this case, it is set by pulling the molding material made of polyvinylidene fluoride with a gripping tool while passing through the gap between the opening of the outer diameter die having the opening and the inner diameter plug arranged inside the opening. It is molded into a cylindrical shape with a different diameter and wall thickness. Then, an inner conductor layer 13 and an outer conductor layer 14 having a thickness set on the inner surface and the outer surface of the piezoelectric body 12 are formed by a known arc vapor deposition method using a vacuum chamber.

In addition, polyvinylidene fluoride is a polymer material that produces a piezoelectric effect when a high voltage is applied and polarized, and has the property of generating electricity when an external force is applied to it and causing distortion when a voltage is applied. .. The piezoelectric body 12 is subjected to a polarization treatment, and a voltage is induced between the inner conductor layer 13 and the outer conductor layer 14 when an external force is applied to the piezoelectric body 12. Further, when a voltage is applied between the inner conductor layer 13 and the outer conductor layer 14, the piezoelectric body 12 is deformed (distorted). Although not shown, the surface of the glove-shaped tactile sensor 10 is covered with a protective cover made of an insulating resin film.

FIG. 3 shows a detection unit 20 provided in the robot to which the tactile sensor 10 is attached. In addition to the tactile sensor 10, the detection unit 20 includes a detection circuit 21, an A / D conversion circuit 22, and a CPU 23. The detection circuit 21 includes an impedance conversion circuit, an amplifier circuit, and a low-pass filter. Then, the detection circuit 21 amplifies the level of the detection signal sent from the tactile sensor 10 after matching it to a predetermined level when the grip portion of the robot grips the agricultural product, and also amplifies the cutoff frequency, which is the limit of the system response. A component having a higher frequency is attenuated and cut off, and a component having a frequency lower than the cutoff frequency is sent to the A / D conversion circuit 22.

The A / D conversion circuit 22 converts the signal sent from the detection circuit 21 into a digital signal and sends it to the CPU 23. The CPU 23 executes various processes performed by the detection unit 20. Here, the CPU 23 determines the positions and voltages of the warp threads 11a and the weft threads 11b that generate a voltage from the piezoelectricity generated in the warp threads 11a and the weft threads 11b constituting the tactile sensor 10 when pressure is applied to the tactile sensor 10. By calculating the size, it is determined which part of the tactile sensor 10 and how much pressure is applied. Further, the detection unit 20 is provided with a ROM for storing a program executed by the CPU 23, a RAM for temporarily storing data used for processing of the CPU 23, and the like, as well as operation buttons for operating the robot. It is equipped with an operation unit and a drive unit equipped with a switch.

As described above, the tactile sensor 10 according to the present embodiment is formed by knitting the cable-shaped pressure sensor 11 as warp threads 11a and weft threads 11b in a woven fabric shape. Each cable-shaped pressure sensor 11 is configured by forming a thin inner conductor layer 13 on the inner peripheral surface of the cylindrical piezoelectric body 12 and forming a thin outer conductor layer 14 on the outer peripheral surface of the piezoelectric body 12. The piezoelectric body 12 is formed in an ultrafine cylindrical shape made of polyvinylidene fluoride having flexibility and elasticity. Therefore, the cable-shaped pressure sensor 11 can be easily deformed in any direction around the axis, can be expanded and contracted in the axial direction, and can be easily deformed in the radial direction so that the cross-sectional shape changes. Then, the tactile sensor 10 has a shape of a thin woven fabric that can be deformed, and even if the surface of the crop to be detected is formed unevenly, it can be bent along the shape, and the grip portion of the robot can be formed. When grasping a crop, the force received from the crop and its distribution can be detected with high sensitivity.

Further, since the piezoelectric body 12 is made of polyvinylidene fluoride, the cable-shaped pressure sensor 11 can obtain good piezoelectricity. 4 (a) and 4 (b) show the states of the two cable-shaped pressure sensors 11 constituting the overlapping warp threads 11a and weft threads 11b when pressure is applied to the tactile sensor 10, and FIGS. The state before the pressure is applied is shown, and FIG. 4B shows the state when the pressure is applied. Before pressure is applied, the cross-sectional shape of each cable-shaped pressure sensor 11 is in a state close to a perfect circle with almost no deformation, but when pressure is applied, each cable-shaped pressure sensor 11 becomes large in pressure. It is crushed accordingly and its cross-sectional shape changes to an elliptical shape.

At this time, compressive stress is generated on the inner surface side of both side portions (the left and right sides of the cross section of FIG. 4B) of the piezoelectric body 12 of the cable-shaped pressure sensor 11 deformed into an elliptical shape, and the cable-shaped pressure sensor 11 is pulled toward the outer surface side. Distort so that stress is generated. The piezoelectric body 12 generates a voltage according to the amount of deformation. Therefore, a larger voltage is generated in the cable-shaped pressure sensor 11 which is greatly deformed by the pressure, and the tactile sensor 10 can exhibit good detection sensitivity. Further, since the inner conductor layer 13 and the outer conductor layer 14 are composed of a silver vapor deposition layer, they can be formed into an ultrathin layer. Along with this, the diameter of the cable-shaped pressure sensor 11 can be reduced, the weight can be reduced, and the cost can be reduced. Further, based on the pressure value detected by the tactile sensor 10, the driving unit of the robot drives the gripping unit under the control of the CPU 23.

(Modified example of the first embodiment)
As a modification of the first embodiment described above, the piezoelectric film 12a shown in FIG. 5 can be used to form the piezoelectric body 12. The piezoelectric film 12a is composed of an elongated rectangular sheet made of polyvinylidene fluoride, and an inner band-shaped layer 13a for forming the inner conductor layer 13 is formed in the central portion in the width direction of one of the surfaces. .. The piezoelectric body 12 is formed in a cylindrical shape by winding both edge portions 12b in the width direction of the piezoelectric film 12a so as to overlap each other, and the inner strip-shaped layer 13a is a portion of the piezoelectric film 12a excluding the overlapping both edge portions 12b. Is formed in. Then, an outer conductor layer 14 is formed on the outer peripheral surface of the piezoelectric body 12 as in the cable-shaped pressure sensor 11 described above.

When the piezoelectric film 12a is wound in a cylindrical shape, for example, the piezoelectric film 12a in which the internal band-shaped layer 13a is formed is wound around a core wire made of a material that is easily dissolved or evaporated to form a cylindrical shape, and then the core wire is formed. A method of dissolving or evaporating and removing the film can be used. The diameter of the core wire is preferably 0.15 mm to 0.55 mm, preferably 0.30 mm. The outer conductor layer 14 can be formed by vapor deposition of silver as in the first embodiment described above, but it may also be formed by using a plating layer of another metal or by applying a conductor resin. Good. The conductor resin may be impregnated by utilizing the capillary phenomenon. Further, in this modification, the width of the piezoelectric film 12a is 3.5 mm and the length is 200 m, and a cylindrical body composed of the piezoelectric body 12, the inner conductor layer 13 and the outer conductor layer 14 is formed slightly thicker to form a cylinder. The diameter and wall thickness are set by pulling after forming into a shape.

The dimensions of each part of the piezoelectric film 12a are as follows: length 10 mm to 1000 mm, preferably 100 mm to 500 mm, width 1 mm to 10 mm, preferably 1.5 mm to 5 mm, and thickness 8 μm to 120 μm, preferably. It is set to 15 μm to 40 μm, most preferably 20 μm. Further, when the width of the piezoelectric film 12a is 3.5 mm as described above, the width of the inner strip-shaped layer 13a is set to 1.3 mm to 1.7 mm, and the width of the edge portions 12b on both sides of the inner strip-shaped layer 13a is set. Is preferably set to 0.9 mm to 1.1 mm. In this case, the inner conductor layer 13 has a gap extending in the longitudinal direction. Further, in FIG. 5, the inner strip-shaped layer 13a is not formed at both ends of the piezoelectric film 12a in the longitudinal direction, but the inner strip-shaped layer 13a may extend to both ends of the piezoelectric film 12a in the longitudinal direction. .. Further, as another modification, an energizing layer may be formed on the surface of the core wire described above to form an internal conductor layer, and the core wire may be left as it is.

(Second Embodiment)
6 (a) and 6 (b) show a cable-shaped pressure sensor 31 constituting a tactile sensor (not shown) according to a second embodiment of the present invention. Similar to the cable-shaped pressure sensor 11 described above, the cable-shaped pressure sensor 31 forms a thin inner conductor layer 33 on the inner peripheral surface of the cylindrical piezoelectric body 32, and has a thin outer conductor layer 34 on the outer peripheral surface of the piezoelectric body 32. The piezoelectric body 32 and the inner conductor layer 33 are each formed in a cylindrical shape by spirally winding an elongated material.

As shown in FIG. 5, a piezoelectric film having an internal band-shaped layer formed similar to the piezoelectric film 12a having an internal band-shaped layer 13a formed is used for manufacturing the cable-shaped pressure sensor 31. Then, the piezoelectric film is spirally rolled into a cylindrical shape so that the inner strip-shaped layer is on the inside, and the edges of the overlapping piezoelectric films are joined to each other. As a result, the sensor center portion 31a including the piezoelectric body 32 shown in FIG. 7 and the inner conductor layer 33 (see FIG. 6B) is obtained. A spirally extending gap 33a is formed between the edges of the inner conductor layer 33 in the width direction. In this case, the piezoelectric film can also be wound by using the core wire made of the above-mentioned material that is easily dissolved or evaporated. Next, the outer conductor layer 34 is formed on the outer peripheral surface of the piezoelectric body 32 to obtain the cable-shaped pressure sensor 31. The outer conductor layer 34 is also formed by vapor deposition of silver, plating of other metals, coating of a conductor resin, or the like.

The inner and outer diameters of the piezoelectric body 32 are substantially the same as those of the piezoelectric body 12 described above, and the thicknesses of the inner conductor layer 33 and the outer conductor layer 34 are substantially the same as the thicknesses of the inner conductor layer 13 and the outer conductor layer 14 described above. Is. The plurality of cable-shaped pressure sensors 31 configured in this way are divided into two sets, and the tactile sensor 10 shown in FIG. 1 is formed by assembling the cable-shaped pressure sensors 31 so that one is a warp and the other is a weft. A similar tactile sensor can be obtained.

According to the cable-shaped pressure sensor 31 according to the present embodiment, since the inner conductor layer 33 is composed of an inner band-shaped layer previously formed on the piezoelectric film, the formation becomes easy. Further, by changing the diameter of the core wire used for winding the piezoelectric film and the winding method of the piezoelectric film, the shape, inner diameter, outer diameter, thickness, and other dimensions of each part constituting the cable-shaped pressure sensor 31 can be arbitrarily set. .. The tactile sensor formed by using the cable-shaped pressure sensor 31 also has the same effect as that of the tactile sensor 10 described above.

(Third Embodiment)
8 (a) and 8 (b) show a cable-shaped pressure sensor 41 constituting a tactile sensor (not shown) according to a third embodiment of the present invention. The cable-shaped pressure sensor 41 is configured by forming a thin inner conductor layer 43 on the inner peripheral surface of the cylindrical piezoelectric body 42 and forming a thin outer conductor layer 44 on the outer peripheral surface of the piezoelectric body 42. In the cable-shaped pressure sensor 41, the piezoelectric body 42, the inner conductor layer 43, and the outer conductor layer 44 are all formed into a cylindrical shape or a substantially cylindrical shape by spirally winding an elongated material. The piezoelectric body 42 is formed in a cylindrical shape, but the inner conductor layer 43 and the outer conductor layer 44 are formed in a spiral shape with gaps 43b and 44b, respectively, like a coil spring.

When manufacturing this cable-shaped pressure sensor 41, first, as shown in FIG. 9, an inside made of a thin layer of silver is centered in the width direction of one surface (upper surface in FIG. 8) of the piezoelectric film 42a. The band-shaped layer 43a is formed, and an outer band-shaped layer 44a made of a thin layer of silver is formed at the center of the other surface (lower surface in FIG. 9) of the piezoelectric film 42a in the width direction to serve as the sensor material 41a. Next, the sensor material 41a is spirally rolled into a cylindrical shape so that the inner strip-shaped layer 43a is on the inside and the outer strip-shaped layer 44a is on the outside, and the edges 42b of the overlapping piezoelectric films 42a are joined to each other. As a result, a cable-shaped pressure sensor 41 composed of the piezoelectric body 42, the inner conductor layer 43, and the outer conductor layer 44 is obtained. In this case, the edges 42b of the piezoelectric film 42a are preferably bonded to each other by adhesion or crimping. Further, the sensor material 41a can be wound by using the core wire made of the above-mentioned material that is easily dissolved or evaporated.

The inner and outer diameters of the piezoelectric body 42 are substantially the same as those of the piezoelectric body 12 described above, and the thicknesses of the inner conductor layer 43 and the outer conductor layer 44 are substantially the same as the thicknesses of the inner conductor layer 13 and the outer conductor layer 14 described above. Is. A tactile sensor can be obtained by dividing the plurality of cable-shaped pressure sensors 41 configured in this manner into two sets and assembling them so that one is a warp and the other is a weft to form a woven fabric.

According to the cable-shaped pressure sensor 41 according to the present embodiment, since the inner conductor layer 43 and the outer conductor layer 44 are composed of the inner band-shaped layer 43a and the outer band-shaped layer 44a previously formed on the piezoelectric film 42a, the formation is easy. Become. Also in this case, by changing the diameter of the core wire used for winding the sensor material 41a and the winding method of the sensor material 41a, the shape, inner diameter, outer diameter, thickness, etc. of each part constituting the cable-shaped pressure sensor 41 can be changed. The dimensions of can be set arbitrarily. The tactile sensor formed by using the cable-shaped pressure sensor 41 also has the same effect as that of the tactile sensor 10 described above. Further, as a modification of the present embodiment, instead of winding the sensor material 41a in a spiral shape, the edge portions 42b can be joined together while being straight to form a cylindrical shape.

(Fourth Embodiment)
10 (a) and 10 (b) show a cable-shaped pressure sensor 51 constituting a tactile sensor (not shown) according to a fourth embodiment of the present invention. The cable-shaped pressure sensor 51 is formed by twisting a plurality of sensor electric wires 51a into a twisted yarn shape, and each sensor electric wire 51a is configured to be the same as the cable-shaped pressure sensor 11 of the first embodiment described above. However, it needs to be extremely fine. The sensor wire 51a preferably has an outer diameter of 0.18 mm and an inner diameter of about 0.16 mm. Then, the tactile sensor can be obtained by dividing the plurality of cable-shaped pressure sensors 51 configured in this way into two sets and assembling them so that one is a warp and the other is a weft to form a woven fabric.

In the tactile sensor according to the present embodiment, since the cable-shaped pressure sensor 51 is composed of a plurality of sensor electric wires 51a, the strength is increased and the sensitivity is improved. Further, since each cable-shaped pressure sensor 51 is more easily bent by an external force and is more easily expanded and contracted in the axial direction due to the twisting, the tactile sensor composed of the cable-shaped pressure sensor 51 is more flexed along the object to be detected. It will be easier. Further, by configuring the cable-shaped pressure sensor 51 with a plurality of sensor wires 51a, even if a part of the sensor wires 51a is cut, the other sensor wires 51a can maintain the function as the cable-shaped pressure sensor 51. it can.

The other effects of the cable-shaped pressure sensor 51 and the tactile sensor using the cable-shaped pressure sensor 51 are the same as those of the cable-shaped pressure sensor 11 and the tactile sensor 10 using the cable-shaped pressure sensor 11 described above. Further, as a modification of the cable-shaped pressure sensor 51, the sensor wire used as each sensor wire 51a may be configured by the cable-shaped pressure sensor 31 or 41 instead of the cable-shaped pressure sensor 11.

(Fifth Embodiment)
FIG. 11 shows a cross section of a cable-shaped pressure sensor 61 constituting a tactile sensor (not shown) according to a fifth embodiment of the present invention. The cable-shaped pressure sensor 61 forms a thin inner conductor layer 63 on the inner peripheral surface of the cylindrical piezoelectric body 62, forms a thin outer conductor layer 64 on the outer peripheral surface of the piezoelectric body 62, and further forms a thin outer conductor layer 64 on the outer peripheral surface of the piezoelectric body 62. It is configured by forming an insulating sheath 65 on the outer peripheral surface. The central portion composed of the piezoelectric body 62, the inner conductor layer 63, and the outer conductor layer 64 has the same configuration as the cable-shaped pressure sensor 11 described above. The outer conductor layer 64 may be formed by winding a very fine copper wire or a plated copper wire having a diameter of, for example, 0.08 mm around the outer peripheral surface of the piezoelectric body 62.

The insulating sheath 65 is formed by winding an ultrathin polyester tape around the outer peripheral surface of the outer conductor layer 64, and the thickness is set to about 15 μm to 100 μm, preferably about 50 μm. Then, the tactile sensor can be obtained by knitting the plurality of cable-shaped pressure sensors 61 configured in this manner so as to form warp threads and weft threads to form a woven fabric. In the tactile sensor according to the present embodiment, the strength of each cable-shaped pressure sensor 61 is increased, so that damage can be prevented and the life can be extended. The other effects of the cable-shaped pressure sensor 61 and the tactile sensor using the cable-shaped pressure sensor 61 are the same as those of the cable-shaped pressure sensor 11 and the tactile sensor 10 using the cable-shaped pressure sensor 11 described above. Further, as a modification of the cable-shaped pressure sensor 61, the central portion may be configured by any of the cable-shaped pressure sensors 31, 41, 51 instead of the cable-shaped pressure sensor 11.

Further, the present invention is not limited to each of the above-described embodiments, and can be appropriately modified and implemented. For example, in the above-described embodiment, the tactile sensor 10 and the like are of the glove type attached to the grip portion of the robot for harvesting agricultural products, but the tactile sensor according to the present invention is not limited to this, and various machines are used. , Can be used by changing the shape to an instrument. For example, it can be used in various fields such as artificial limbs and artificial limbs for medical use, massage instruments for rehabilitation, and inspection instruments for ultrasonic flaw detection inspection. In this case, the shape of the tactile sensor is made according to the purpose. In short, a tactile sensor can be used as long as it is a machine or instrument that measures the pressure from the outside or achieves the purpose by deforming the piezoelectric body.

Further, the material and dimensions of the respective parts constituting the cable-shaped pressure sensors 11, 31 and the like described above can be appropriately changed. For example, the diameter of the cable-shaped pressure sensors 11, 31 and the like can be set in the range of 8 μm to 100 μm. Further, in each of the above-described embodiments, the warp threads 11a and the weft threads 11b of the tactile sensor 10 and the like are all composed of any of the cable-shaped pressure sensors 11, 31, 41, 51, 61, but the warp threads 11a and the weft threads 11b. One may be composed of any of the cable-shaped pressure sensors 11, 31, 41, 51, 61, and the other may be composed of general fibers or the like. In this case, it is more preferable to use any of the cable-shaped pressure sensors 11, 31, 41, 51, 61 as the weft thread 11b. Further, the inner conductor layers 13, 33 and the like may be filled with ultrafine fibers having excellent flexibility and elasticity.

10 ... Tactile sensor, 11, 31, 41, 51, 61 ... Cable-shaped pressure sensor, 12, 32, 42, 62 ... Piezoelectric body, 12a, 42a ... Piezoelectric film, 12b, 42b ... Edge, 13, 33, 43 , 63 ... Inner conductor layer, 13a, 43a ... Inner strip layer, 14, 34, 44, 64 ... Outer conductor layer, 44a ... Outer strip layer, 51a ... Sensor wire, 65 ... Insulating sheath.

Claims (6)

E Bei an elongated cylindrical piezoelectric body having flexibility, and an internal conductor layer formed on the inner surface of said piezoelectric body, a cylindrical sensor wire consisting of an outer conductor layer formed on the outer surface of the piezoelectric body ,
The piezoelectric body is formed by winding a flat band-shaped piezoelectric film in a cylindrical shape, and when the internal conductor layer is formed on one surface side of the piezoelectric film and the piezoelectric film is wound in a cylindrical shape. Consists of an inner strip layer arranged to be located on the inner surface side,
The inner strip-shaped layer is formed in the central portion in the width direction of one surface of the piezoelectric film, and the piezoelectric film is formed into the cylindrical piezoelectric body in contact with the edges on which the inner strip-shaped layer is not formed. cable-like pressure sensor, characterized in that you have formed. A cylindrical sensor wire composed of a flexible elongated cylindrical piezoelectric body, an inner conductor layer formed on the inner surface of the piezoelectric body, and an outer conductor layer formed on the outer surface of the piezoelectric body.
Before SL piezoelectric body is formed by winding by contacting the edge with each other in the width direction of the flat belt of the piezoelectric film into a cylindrical shape, the inner conductor layer, the width direction of the one surface of the piezoelectric film It is composed of an inner band-shaped layer formed in a central portion excluding the edge portion and arranged so as to be located on the inner surface side when the piezoelectric film is wound in a cylindrical shape, and the outer conductor layer is the other of the piezoelectric film. Ke characterized that you have been configured outside strip layer disposed so as to be positioned on the outer surface when said piezoelectric film is formed in a central portion excluding the edge portion in the width direction of the surface is wound in a cylindrical shape -Bull-shaped pressure sensor. The cable-shaped pressure sensor according to claim 1 or 2, wherein a plurality of the sensor electric wires are twisted together to form a twisted yarn. The cable-shaped pressure sensor according to any one of claims 1 to 3, wherein the outer periphery of the outer conductor layer is coated with an insulating sheath. The cable-shaped pressure sensor according to any one of claims 1 to 4, wherein the outer diameter of the sensor electric wire is set to 0.2 mm to 0.8 mm. A tactile sensor formed by assembling the cable-shaped pressure sensor according to any one of claims 1 to 5 in a cloth shape.

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