JP2004245717A - Contact pressure sensor and grasp robot - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately detect three component forces (in X-direction, Y-direction, and Z-direction) from a small force with respect to a contact pressure sensor for detecting a force (pressure) acting on a mounting surface and a grasp robot using a contact pressure sensor for contact pressure detection. <P>SOLUTION: This contact pressure sensor is equipped with a disk-shaped first strain part, second to fifth strain parts extended in plate form from positions at which the periphery of the first strain part is divided into four substantially at equal angles and structured to support the first strain part by serving as legs for the first strain part, first to fourth foot parts severally extended from the second to fifth strain parts to sides different from the first strain part, a diaphragm-shaped first strain gage attached onto a disk surface of the first strain part, and second to fifth strain gages attached severally onto plate surfaces of the second to fifth strain parts. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tactile pressure sensor that detects a force (pressure) applied to a mounting surface, and a gripping robot that uses the tactile pressure sensor for tactile pressure detection. In particular, the present invention relates to a three-component force (X direction, The present invention relates to a tactile pressure sensor suitable for detecting (Y direction, Z direction) and a gripping robot using the same.
[0002]
[Prior art]
As a tactile pressure sensor that can be attached to a fingertip, for example, there is one used in a “flexible object gripping device” described in Japanese Patent Application Laid-Open No. 8-323678. This sensor detects a contact area by installing a large number of minute ON / OFF switches. The size and flexibility of the object are recognized from the relationship between the detected contact area and the opening amount of the fingertip, and it is intended that optimal object grasping is performed. The sensor basically detects a force in a direction (Z direction) perpendicular to the mounting surface.
[0003]
As a product supplied to the market, there is a “BIG-MAT” surface pressure measuring system manufactured by Nitta Corporation, which uses a sensor sheet to measure the in-plane pressure distribution. Although it is intended to measure a high density pressure distribution with the sensor sheet, again only the pressure distribution in the Z direction is measured.
[0004]
In the “force detection device” described in Japanese Patent Laid-Open No. 2002-181640, electrostatic force type force detection is shown. In this detection device, in addition to the Z-direction force, the X-direction force can also be detected. Force detection in the Z direction is performed based on an ON / OFF switch, and is limited as force detection.
[0005]
The “force sensor” described in Japanese Patent Application Laid-Open No. 2000-266620 is configured to detect a total of six component forces including a force in three directions and a moment about three axes. As a structure, a strain gauge is attached to a three-dimensional cross-shaped rigid body. In this configuration, it is impossible to attach to the surface of the skin or the fingertip, and it is considered that it is not suitable for detecting a small force with high accuracy because a rigid body is used.
[0006]
[Patent Document 1]
JP-A-8-323678
[Patent Document 2]
JP 2002-181640 A
[Patent Document 3]
JP 2000-266620 A
[0007]
[Problems to be solved by the invention]
The present invention has been made in consideration of the above-described situation. In a tactile pressure sensor that detects a force (pressure) applied to a mounting surface and a gripping robot that uses the tactile pressure sensor for tactile pressure detection, the present invention is small and accurate. An object of the present invention is to provide a tactile pressure sensor capable of detecting a three-component force (X direction, Y direction, Z direction) from a force and a gripping robot using the same.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the tactile pressure sensor according to the present invention has a plate-like first strain-generating portion and a plate-like shape from a position where the periphery of the first strain-generating portion is divided into four at substantially equal angles. The second to fifth strain-generating portions, which extend to the first strain-generating portion and support the first strain-generating portion as a leg of the first strain-generating portion, and the second to fifth strain-generating portions. First to fourth legs extending from the respective sides different from the first strain-generating portion, and a diaphragm-shaped first attached to the disk surface of the first strain-generating portion. And the second to fifth strain gauges mounted on the plate surfaces of the second to fifth strain-generating portions, respectively.
[0009]
A second to second structure in which a force (pressure) in the Z direction (a direction perpendicular to the mounting surface) is detected by a first strain gauge attached to the first strain-generating portion and supports the first strain-generating portion. Forces (pressures) in the X direction and the Y direction (each in a direction parallel to the mounting surface (shear direction)) are detected by second to fifth strain gauges respectively attached to the five strain generating portions. Since each of the strain generating portions is plate-shaped and easily bent, detection can be performed from a small force. In addition, a strain gauge dedicated to force detection in each direction is provided, and for example, mutual interference can be reduced to improve detection accuracy.
[0010]
The contact pressure sensor according to the present invention is characterized in that the contact pressure sensors are arranged in an array as elements. The above-mentioned contact pressure sensor can be manufactured minutely, for example, by pressing and punching a plate material, and therefore it is easy to arrange them in an array. By making an array, it is possible to provide a tactile pressure sensor that covers a certain mounting area. Thereby, it becomes possible to detect the contact pressure in the mounting surface with high accuracy.
[0011]
A gripping robot according to the present invention includes the above-described array-shaped contact pressure sensor for detecting contact pressure. The array-shaped tactile pressure sensor occupies a certain area in the mounted state and can be mounted following the roundness of the mounting surface. Therefore, in the gripping robot, for example, by attaching this to the fingertip, it is possible to detect a suitable tactile pressure in combination with the ability to detect a three-component force from a small force with high accuracy.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In addition to the second to fifth strain gauges, the tactile pressure sensor as an embodiment of the present invention is arranged so that strain gauges are respectively attached to both surfaces of the plate surfaces of the second to fifth strain generating portions. Further comprise sixth to ninth strain gauges. When strain gauges are attached to both surfaces of the plate surfaces of the second to fifth strain generating portions, one of the surfaces shows an output of compression and the other shows an output of tension, and the sensitivity can be improved. Therefore, it is possible to accurately detect the three component forces from a small force. Further, by combining the strain gauges on both sides, interference from the force detected by the first strain generating portion can be avoided.
[0013]
In the tactile pressure sensor according to the embodiment, the second to fifth strain-generating portions support the first strain-generating portion. The angle of the fifth strain generating part with the plate is 90 to 130 degrees. This angle can be designed such that the height of the contact pressure sensor is kept small and an area for mounting the strain gauge on the plate surface of the second to fifth strain generating portions is secured. In terms of the simplicity of the structure, 90 degrees can be said to be the most common angle, but by making the angle slightly larger than this, it is easy to ensure the plate surface area without increasing the height.
[0014]
Further, the contact pressure sensor as an embodiment includes a disk area of the first strain-generating portion in the vicinity of an extended boundary from the first strain-generating portion to the second to fifth strain-generating portions, or the A concave portion is formed so as to narrow the plate area of the second to fifth strain generating portions. By providing such a recess, it is possible to reduce the rate at which strain in a direction that does not need to be detected occurs on the plate surface of the second to fifth strain generating portions. Therefore, more accurate force detection with less interference in each detection direction is possible. Thereby, detection accuracy is also improved.
[0015]
Further, the contact pressure sensor as an embodiment includes the second to fifth strain generating portions in the vicinity of an extending boundary from the second to fifth strain generating portions to the first to fourth foot portions. A recess is formed to reduce the plate area. This is also the same as the above.
[0016]
The contact pressure sensor as an embodiment further includes a wiring board that supplies electrical wiring to terminals of the strain gauges disposed in the contact pressure sensor as the element, and the wiring board is formed of a multi-layered structure. A tactile pressure sensor as the element having a wiring layer and connected to each wiring layer is constant. Wiring connected to each element of the array-shaped contact pressure sensor is supplied by a multilayer wiring board. Here, since the tactile pressure sensor connected to each wiring layer is constant, the structure of the multilayer wiring board can be simplified. For example, a multilayer structure that does not use any through holes can be used.
[0017]
Based on the above, embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a schematic structure of a contact pressure sensor according to an embodiment of the present invention. FIG. 1A is a perspective view, and FIG. 1B is a cross-sectional view of the X direction (direction of force in the X direction) as seen sideways.
[0018]
As shown in FIG. 1, this tactile pressure sensor has a plate-like strain generating portion 1 formed on plate-like strain generating portions 2a, 2b, 3a, 3b extending from a position where the periphery thereof is divided into almost four parts. It has a supported shape. The plate-shaped strain generating portions 2a, 2b, 3a, 3b are legs of the disk-shaped strain generating portion 1, and feet for fixing to the mounting surface on the side opposite to the strain generating portion 1 side, respectively. Portions 12a, 12b, 13a, and 13b are provided.
[0019]
Diaphragm-shaped strain gauges 8a, 8b, 8c, and 8d are attached to the lower surface of the disc-shaped strain generating portion 1, and on both surfaces of the plate-shaped strain generating portions 2a, 2b, 3a, and 3b, Strain gauges 4a, 4b, 4c, 4d, 5a,... (Total 8) are provided. The diaphragm-shaped strain gauges 8a, 8b, 8c, and 8d will be further described later with reference to FIG. The strain gauges 4a, 4b, 4c, 4d, 5a,... On the plate-like strain generating portions 2a, 2b, 3a, 3b are each in the direction from the periphery of the strain generating portion 1 to the feet 12a, 12b, 13a, 13b. In order to detect strain against deformation such as bending in the plate, it is installed so that its longitudinal direction is parallel to that direction.
[0020]
In this embodiment, the angle between the strain-generating portion 1 on the disc and the plate-like strain-generating portions 2a, 2b, 3a, and 3b, which are the legs, is 105 degrees. This is because the area of the plate-like strain generating portions 2a, 2b, 3a, and 3b is ensured by making it slightly larger than 90 degrees without making the height of the contact pressure sensor so high. If the obtuse angle is further reduced, the height as the tactile pressure sensor is reduced, but the height is increased in the plane direction, so the arrangement density as the tactile pressure sensor has to be reduced. In order to suppress the size typified by the height to some extent and to secure the arrangement density, it is considered appropriate to design this angle from 90 degrees to 130 degrees. Among these, if it is set to about 100 to 110 degrees, it contributes to securing the size of the plate-like strain generating portions 2a, 2b, 3a, 3b, and thereby the strain gauges 4a, 4b, 4c, 4d, 5a,. Convenient for installation.
[0021]
Specific dimensions are, for example, about 1 mm to 3 mm in height, and about 5 mm to 15 mm in total length in the X direction and Y direction including the feet 12a, 12b, 13a, and 13b. The plate thickness of the strain generating portions 1, 2a, 2b, 3a, 3b is, for example, about 0.05 mm to 0.3 mm, and as the material thereof, a material having moderate rigidity such as a metal such as stainless steel or a resin is used. it can. In the case of metal, for example, it can be easily processed and manufactured including bending by pressing and punching. In the case of resin, it can be manufactured by a mold using a mold, for example.
[0022]
Further, as shown in the figure, in the vicinity of the boundary between the strain-generating portion 1 on the disc and the plate-like strain-generating portions 2a, 2b, 3a, 3b, a recess is formed so as to reduce the area of these discs and plates. 6 is formed (one of the circular plate and the plate may be narrowed). A recess 7 is also formed near the boundary between the plate-like strain generating portions 2a, 2b, 3a and 3b and the foot portions 12a, 12b, 13a and 13b so as to reduce the area of these plates. These concave portions 6 and 7 are strains generated in the plate-like strain generating portions 2a, 2b, 3a, and 3b, and are increased as much as possible by the strain gauges 4a, 4b, 4c, 4d, 5a,. Therefore, it is provided.
[0023]
That is, for example, for the force in the X direction, the bending of the strain generating portions 2a and 2b is preferable for sensitive pressure detection. However, with respect to the force in the X direction, bending stress around the normal lines of the strain generating portions 3a and 3b is generated in the strain generating portions 3a and 3b, so that the rigidity becomes considerably high. Therefore, when the concave portions 6 and 7 are provided as described above, bending stress around the normal lines of the strain-generating portions 3a and 3b is concentrated, so that it is easy to bend (easily deform in the X direction). The same applies to the Y direction. As a result, it is possible to detect even with a smaller force.
[0024]
Although not shown in FIG. 1, an elastic material such as urethane rubber may be bonded to the upper surface of the disk-shaped strain generating portion 1 to obtain a function of weight buffering.
[0025]
FIG. 2 is a diagram schematically showing a configuration of the diaphragm-shaped strain gauges 8a, 8b, 8c, and 8d attached to the lower surface of the disc-shaped strain generating portion 1. As shown in FIG. In FIG. 2, the parts corresponding to the components shown in FIG.
[0026]
As shown in FIG. 2, the strain gauges 8a, 8b, 8c, 8d are provided on a circular sheet 20 as a whole. The lines constituting the strain gauges 8a, 8b, 8c, and 8d are arranged from the connection pad 21 to the connection pad 22 through the strain gauge 8a having a longitudinal direction in the radial direction of the sheet 20, and further to the connection pad 22. To the connection pad 23 through a strain gauge 8d having a longitudinal direction arranged in the circumferential direction of the sheet 20, and further from the connection pad 23 to a strain gauge having a longitudinal direction arranged in the radial direction of the sheet 20. -It leads to the connection pad 24 through the gauge 8b, and further to the connection pad 25 from the connection pad 24 through the strain gauge 8c in which the longitudinal direction is arranged in the circumferential direction of the sheet 20.
[0027]
The strain gauges 8 a and 8 b, whose longitudinal directions are arranged in the radial direction of the sheet 20, are provided on the side close to the periphery of the sheet 20 so as to face each other on the sheet 20. The strain gauges 8c and 8d whose longitudinal direction is arranged in the circumferential direction of the sheet 20 are provided on the side close to the center of the sheet 20 so as to face each other.
[0028]
The strain gauges 8a and 8b on the peripheral side and the strain gauges 8c and 8d on the center side detect opposite strains (that is, compressive strain and tensile strain) by deformation of the strain generating portion 1. This will be described below. As shown in the figure, hereinafter, the resistance value of one peripheral strain gauge 8a is Z1a, the resistance value of the other peripheral strain gauge 8b is Z1b, and the resistance value of one central strain gauge 8c is Z2a. The resistance value of the other central strain gauge 8d is represented by Z2b.
[0029]
FIG. 3 is a diagram for explaining the principle by which the tactile pressure sensor shown in FIG. 1 detects a force in the Z direction. In FIG. 3, the same reference numerals are given to the components corresponding to the constituent elements in the drawings already described.
[0030]
As shown in FIG. 3A, when a force Fz in the Z direction is applied to the contact pressure sensor, changes in the diaphragm-like strain gauges 8a, 8b, 8c, and 8d according to the strain occur. That is, the center side strain gauges 8c and 8d are changes according to tension, and the peripheral side strain gauges 8a and 8b are changes according to compression. The reason why the peripheral strain gauges 8a and 8b change according to the compression is that there is a neutral position between the central strain gauges 8c and 8d and the peripheral strain gauges 8a and 8b. At the center side from the neutral point, the strain-generating part 1 bends downwardly, and at the peripheral side from the neutral point, the strain-generating part 1 bends upwardly.
[0031]
As shown in FIG. 3B, the strain gauges 8a, 8b, 8c, and 8d are connected to form a bridge. An input voltage (or current) is applied from the input terminal pair 34 and 35 of the bridge, and an output is obtained between the output terminal pair 21 and 23. When there is no change in the strain gauges 8a, 8b, 8c, and 8d, the strain gauge is satisfied so that the equilibrium condition of the bridge circuit: Z1a · Z1b = Z2a · Z2b (= impedance product between opposing elements is the same) is satisfied. If the resistances of the screws 8a, 8b, 8c, and 8d are adjusted, the equilibrium is lost when the resistance of the strain gauges 8a, 8b, 8c, and 8d changes.
[0032]
As described above, the resistances of the center side strain gauges 8c and 8d increase according to tension, and the resistances of the peripheral side strain gauges 8a and 8b decrease according to compression. Therefore, when the strain generating portion 1 detects a force in the Z direction, a voltage is generated between the connection pad 21 and the terminal 23. The force in the Z direction can be detected by detecting this voltage (or current by this voltage). The detection of this force is well proportional to Fz within the elastic limit of the strain generating portion 1.
[0033]
FIG. 3C is a diagram for explaining changes in the strain gauges 4a, 4b, 4c, and 4d for detecting the force in the X direction that occurs when the force Fz in the Z direction is applied (this is the case). The same applies to the strain gauges 5a for detecting the force in the Y direction).
[0034]
When the force Fz in the Z direction is applied, strain is also generated in the strain generating portions 2a and 2b to which the strain gauges 4a, 4b, 4c and 4d are attached. As can be seen from the structure shown in FIG. 3A, the strains are strains in which the outer strain gauges 4a and 4d are tensile and the inner strain gauges 4b and 4c are compressed.
[0035]
Here, as shown in FIG. 3C, the strain gauges 4a, 4b, 4c, and 4d are connected to form a bridge. That is, the strain gauge 4b attached to one inner side of the opposing strain generating portions 2a and 2b and the strain gauge 4d attached to the other outer side serve as elements of one opposing bridge, and are attached to one outer side. The strain gage 4a and the strain gage 4c attached to the other inner side serve as elements of the other opposing bridge. Then, an input is applied from the input terminal pair 44 and 45 of this bridge, and an output is obtained between the output terminal pair 42 and 43.
[0036]
In such a bridge configuration, due to the strain described above, the resistance X1 of the strain gauge 4b decreases, the resistance X1 * of the strain gauge 4a increases, the resistance X2 of the strain gauge 4c decreases, and the resistance X2 * of the strain gauge 4d. And the balanced condition of the bridge circuit: X1 · X2 * = X2 · X1 * remains held. In this sense, interference from Fz detection to Fx detection (Fy detection) is greatly reduced. This is a great advantage of this embodiment.
[0037]
FIG. 4 is a diagram for explaining the principle by which the tactile pressure sensor shown in FIG. 1 detects a force in the X direction. In FIG. 4, the same reference numerals are given to the components corresponding to the constituent elements in the drawings already described. (The description of FIG. 4 is the same when the principle of detecting the force in the Y direction is described.)
[0038]
As shown in FIG. 4A, when a force Fx in the X direction is applied to the tactile pressure sensor, the strain gauges 4a, 4b, 4c, and 4d attached to the opposing strain-generating portions 2a and 2b respond to the strain. Changes occur. That is, as shown in the figure, the strain gauge 4a outside the strain generating portion 2a on the output direction side of the force Fx and the strain gauge 4c inside the strain generating portion 2b on the input direction side are changes according to compression, and the force Fx The strain gauge 4b inside the strain generating portion 2a on the output direction side and the strain gauge 4d outside the strain generating portion 2b on the input direction side are changes according to tension.
[0039]
As already described, the strain gauges 4a, 4b, 4c, and 4d are connected in a bridge configuration as shown in FIG. Therefore, due to the above change, the resistance X1 of the strain gauge 4b increases, the resistance X1 * of the strain gauge 4a decreases, the resistance X2 of the strain gauge 4c decreases, and the resistance X2 * of the strain gauge 4d increases, thereby balancing the bridge circuit. Condition: X1 · X2 * = X2 · X1 * is broken. Therefore, a voltage is generated between the output terminal pair 42 and 43. The force in the X direction can be detected by detecting this voltage (or current by this voltage). The detection of this force is well proportional to Fx within the elastic limit of the strain generating portions 2a, 2b.
[0040]
FIG. 4C is a diagram for explaining changes in the strain gauges 8a, 8b, 8c, and 8d for detecting the force in the Z direction, which is generated when the force Fx in the X direction is applied. Even when the force Fx in the X direction is applied, as shown in FIG. 4A, almost no strain is generated in the strain generating portion 1 to which the strain gauges 8a, 8b, 8c, and 8d are attached.
[0041]
Therefore, the bridge circuit for detecting the force in the Z direction described above maintains the balance of the bridge circuit because there is almost no resistance change in the strain gauges 8a, 8b, 8c, and 8d as shown in FIG. 4 (c). It is. That is, there is almost no interference from Fx detection (or Fy detection) to Fz detection.
[0042]
As described above, in this embodiment, the strain-generating portions 1, 2 a, 2 b, 3 a, and 3 b are formed in a plate shape, and a recess is provided in the vicinity of the boundary between the strain-generating portions or other parts, so that the strain becomes a leg. Strain gauges 4a, 4b, 4c, 4d, 5a,... (Total 8) are attached to both surfaces of the parts 2a, 2b, 3a, 3b, and these are connected as two bridge circuits. As a result, the mutual interference can be greatly reduced, and the three component forces (X direction, Y direction, Z direction) can be accurately detected from a small force.
[0043]
Note that the bridge connection configuration shown in FIG. 4A may be changed to the following bridge configuration. That is, 4a and 4c (that is, X2 + X1 * is arranged) at the position 4a in FIG. 4A, 4d and 4b (that is, X1 + X2 * is arranged) at the position 4d in FIG. The remaining 4b and 4c are bridges formed by connecting external fixed resistors. Even if it does in this way, the same detection sensitivity is obtained and there exists an effect which avoids the interference from the force Fz of Z direction demonstrated in FIG.3 (c).
[0044]
[Example 1]
Examples will be described below. As Example 1, a 0.1 mm-thick metal plate was punched into a cross shape with a press, and was bent while leaving the central plane portion, to produce a contact pressure sensor as shown in FIG. The height of the contact pressure sensor was 1.6 mm.
[0045]
The input voltage to the bridge circuit by the strain gauges 4a, 4b, 4c, 4d (5a,...) Was 5V. The nominal resistance value of each of the strain gauges 4a, 4b, 4c, 4d (5a,...) Is 350Ω. The bottom surfaces of the four feet 12a, 12b, 13a, and 13b of the contact pressure sensor were fixed to the mounting surface, and a force of Fx = 250 g was applied in the X direction. The evaluation items are three points: output voltage of the bridge circuit, interference between Fx detection and Fy detection, and linearity (linearity) of Fx detection.
[0046]
As a result, the output voltage of the bridge circuit was 1.7 mV to 1.8 mV, the interference between Fx detection and Fy detection was within 20%, and the linearity was within ± 1%. As a result, the output voltage of the bridge circuit is detected to be relatively large, and the interference and linearity between the Fx detection and the Fy detection are relatively small as compared with other embodiments described below.
[0047]
[Example 2]
In the second embodiment, the strain gauge is attached to only one side of the strain generating portions 2a, 2b, 3a, 3b (only the outer strain gauges 4a, 4d, 5a,...), And the other structures are the same as in the first embodiment. The structure was the same. This structure is shown in FIG. FIG. 5 is a diagram schematically showing the structure of a tactile pressure sensor according to another embodiment of the present invention. The same components as those already described are given the same reference numerals.
[0048]
In the bridge circuit using the strain gauges 4a and 4d, the elements corresponding to the strain gauges 4b and 4c in the bridge circuit shown in FIG. At this time, similarly to Example 1, a force of Fx = 250 g was applied in the X direction. As a result, the output voltage of the bridge circuit was 0.85 mV to 0.9 mV, the interference between Fx detection and Fy detection was within 20%, and the linearity was within ± 1%. Since the strain gauge is attached to only one side of the strain generating portions 2a, 2b, 3a, 3b, the output is reduced and the detection sensitivity is reduced to about half.
[0049]
[Example 3]
In Example 3, the vicinity of the boundary between the strain generating portion 1 and the four leg strain generating portions 2a, 2b, 3a, 3b, and the strain generating portions 2a, 2b, 3a, 3b and the foot portions 12a, 12b, 13a, No recess was provided near the boundary with 13b. Other configurations are the same as those of the first embodiment. This structure is shown in FIG. FIG. 6 is a diagram schematically showing the structure of a tactile pressure sensor according to still another embodiment of the present invention, where the same components as those already described are given the same reference numerals.
[0050]
As in Example 1, a force of Fx = 250 g was applied in the X direction. As a result, the output voltage of the bridge circuit was 0.5 mV to 0.55 mV, the interference between Fx detection and Fy detection was within 30%, and the linearity was within ± 2%. Since there is no recess, the rigidity of the strain generating portions 2a, 2b, 3a, and 3b is increased, and the output value corresponding to the strain is small because it is difficult to deform. Further, the interference and linearity between Fx detection and Fy detection are also inferior to those of the above embodiments.
[0051]
Next, a contact pressure sensor according to still another embodiment of the present invention will be described with reference to FIG. FIG. 7 is a diagram schematically showing a structure of a contact pressure sensor according to still another embodiment of the present invention. FIG. 7A is a top view and FIG. 7B is a front view.
[0052]
The tactile pressure sensor 70 according to this embodiment is configured to detect the distribution of force on the mounting surface by arranging the tactile pressure sensors shown in FIG. 1 in an array. For example, the total three component forces can be obtained by adding the three component forces applied to the entire fingertip surface by being attached to the fingertip surface or the like and fixed by bonding or the like for each component force. As shown in FIG. 7, this tactile pressure sensor 70 has a tread shape of each tactile pressure sensor and is connected to the adjacent tactile pressure sensor. In this case, a total of twelve pieces of 4 × 3. It is an array of. Such an array configuration can also be manufactured, for example, by pressing and punching a single plate material.
[0053]
Specific dimensions are, for example, about 10 mm to 30 mm in the lateral direction A (more specifically, for example, 15 mm), and about 15 mm to 45 mm (more specifically, for example, 20 mm) in the vertical direction B. The height H is, for example, about 1 mm to 3 mm (more specifically, for example, 1.6 mm).
[0054]
Further, ribbon-like wiring boards 71a, 71b, 71c are respectively attached to the lower side of the contact pressure sensors constituting each column in the vertical direction so as to be fitted into the convex shape of the strain generating portion 1 on the disk. ing. The wiring boards 71a, 71b, 71c supply electrical wiring to a strain gauge attached to a contact pressure sensor as an element. The strain gauge and the wiring board 71a and the like are connected by, for example, solder using lead wires, but they are not shown here.
[0055]
FIG. 8 is a diagram showing the structure of the wiring board 71a (71b, 71c). FIG. 8A is a top view and FIG. 8B is a side view. As shown in FIG. 8, this wiring board is a kind of multilayer wiring board, and has a structure in which insulating layers 91, 92, 93, 94,... And wiring layers 81, 82, 83,. . The insulating layers 91, 92, 93, 94,... Are flexible insulating materials such as polyimide, and the wiring layers 81, 82, 83,. The number of wiring layers 81,... Matches the number of elements in the vertical direction shown in FIG.
[0056]
In FIG. 8, the lowermost wiring layer 81 is exposed on the most distal end side (upper side in the figure), and is exposed at each position farther from the distal end side as the wiring layer is the upper one. The exposed part becomes the connection end with each strain gauge. According to such a configuration of the wiring board 71a, one wiring for each of the strain gauges 4a, 4b, 4c, 4d, 5a,..., 8a to 8d attached to the contact pressure sensor as each element is provided. The wiring layer can be in charge. The wiring board has a very simple structure, and can be inexpensive because it does not require a structure like a through hole even though it is a multilayer board.
[0057]
FIG. 9 is a diagram showing a configuration when the array-like tactile sensor 70 shown in FIG. 8 is attached to the fingertip of the finger portion 100 of the grasping robot. FIG. 9A is a side view and FIG. 9B is a front view. Components corresponding to those shown in FIGS. 8 and 9 are given the same reference numerals.
[0058]
As shown in FIG. 9, the array-like tactile pressure sensor 70 can be mounted following a surface having a minute curved surface such as a human fingertip. Therefore, it is suitable for detecting tactile pressure as various gripping robots. The gripping robot is expected to be applied in various fields such as a washing machine, a vending machine, and a cooker in addition to industrial use.
[0059]
【The invention's effect】
As described above in detail, according to the present invention, the force (pressure) in the Z direction (the direction perpendicular to the mounting surface) is detected by the first strain gauge attached to the first strain generating portion, and the first X-direction and Y-direction (directions parallel to the mounting surface (shear direction) by the second to fifth strain gauges respectively attached to the second to fifth strain-generation sections having a structure that supports the strain generation section. ) Force (pressure) is detected. Since each of the strain generating portions is plate-shaped and easily bent, detection can be performed from a small force. In addition, a strain gauge dedicated to force detection in each direction is provided, and for example, mutual interference can be reduced to improve detection accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic structure of a contact pressure sensor according to an embodiment of the present invention.
2 is a schematic enlarged view showing the configuration of diaphragm-shaped strain gauges 8a, 8b, 8c, and 8d attached to the lower surface of the disk-shaped strain generating portion 1 in FIG.
FIG. 3 is a diagram for explaining the principle that the tactile pressure sensor shown in FIG. 1 detects force in the Z direction.
4 is a diagram for explaining the principle of detecting a force in the X direction by the tactile pressure sensor shown in FIG. 1;
FIG. 5 is a diagram schematically showing a tactile pressure sensor according to another embodiment of the present invention.
FIG. 6 is a diagram schematically showing a tactile pressure sensor according to still another embodiment of the present invention.
FIG. 7 is a view schematically showing the structure of a contact pressure sensor according to still another embodiment of the present invention.
8 is a view showing the structure of the wiring board 71a (71b, 71c) shown in FIG. 7;
9 is a diagram showing a configuration when the array-like tactile pressure sensor 70 shown in FIG. 8 is attached to a fingertip of a finger portion 100 of a grasping robot.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Disk-shaped strain generation part 2a, 2b, 3a, 3b ... Plate-shaped strain generation part 4a, 4b, 4c, 4d, 5a, ... Strain gauge 6, 7 ... Recessed part 8a, 8b ... Strain of peripheral side Gauges 8c, 8d ... Strain gauges 12a, 12b, 13a, 13b on the center side ... Foot 20 ... Sheets of diaphragm-like strain gauges 21, 22, 23, 24 ... Connection pads 34, 35 ... Input terminals 42, 43 of the bridge ... bridge output terminals 44, 45 ... bridge input terminals 70 ... tactile pressure sensors 71a, 71b, 71c ... wiring boards 81, 82, 83 ... wiring layers 91, 92, 93, 94 ... insulating layers 100 ... fingers of the gripping robot portion

Claims (8)

A disk-shaped first strain generating portion;
A structure in which the periphery of the first strain generating portion is extended in a plate shape from a position where the periphery of the first strain generating portion is divided into four at substantially equal angles, and serves as a leg of the first strain generating portion to support the first strain generating portion. Second to fifth strain generating portions;
First to fourth leg portions extending from the second to fifth strain-generating portions, respectively, on a different side from the first strain-generating portion;
A diaphragm-like first strain gauge installed on the disk surface of the first strain-generating portion;
A tactile pressure sensor comprising: second to fifth strain gauges respectively attached to the plate surfaces of the second to fifth strain generating portions. In addition to the second to fifth strain gauges, sixth to ninth strain gauges are further provided so that strain gauges are attached to both surfaces of the plate surfaces of the second to fifth strain generating portions. The tactile pressure sensor according to claim 1. An angle between a disk of the first strain generating portion and a plate of the second to fifth strain generating portions in the structure in which the second to fifth strain generating portions support the first strain generating portion. The tactile pressure sensor according to claim 1, wherein the angle is 90 degrees to 130 degrees. In the vicinity of the extending boundary from the first strain generating portion to the second to fifth strain generating portions, the disk area of the first strain generating portion or the plate of the second to fifth strain generating portions. The tactile pressure sensor according to claim 1, wherein a concave portion is formed so as to reduce an area. A recess is formed in the vicinity of the extending boundary from the second to fifth strain generating portions to the first to fourth foot portions so as to reduce the plate area of the second to fifth strain generating portions. The tactile pressure sensor according to claim 1, wherein: A tactile pressure sensor according to claim 1, wherein the tactile pressure sensor is arranged in an array as an element. A wiring board for supplying electrical wiring to the terminals of the strain gauges disposed in the contact pressure sensors as the elements;
The tactile pressure sensor according to claim 6, wherein the wiring board has a multi-layered wiring layer, and the tactile pressure sensor as the element connected to each wiring layer is constant. A grasping robot comprising the tactile pressure sensor according to claim 6 for tactile pressure detection.

Images