JP2007147443A - Optical touch sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical touch sensor to shorten calculation time for finding force distribution. <P>SOLUTION: A green LED 51 is disposed in a sheet layer 10. When a force is applied to an upper surface part 41 of an enclosure 40, the brightness of a force receiving area with the force applied thereto changes to brightness corresponding to the strength of the force. Force distribution in the surface part 41 of the enclosure 40 is calculated based only on movement information on markers existing in the receiving area. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical tactile sensor, and more particularly to an optical tactile sensor effective for measuring a pressure distribution in a relatively large region.

  A tactile sensor that detects a force applied to each point on a contact surface based on a contact state of the contact surface is known. Here, the force applied to each point on the contact surface is represented by a three-component vector having a magnitude and a direction. This is expressed as f (x, y) in the coordinate system of FIG. However, since f is a vector, it actually has x, y, z3 components at each point. When each component is explicitly indicated, it is expressed as f (x, y) = [fx (x, y), fy (x, y), fz (x, y)]. Since the force distribution has three components at each contact point, in order to reconstruct the force distribution on the contact surface by the tactile sensor, information of at least three degrees of freedom must be obtained for each point on the contact surface.

  Accordingly, the inventors of the present application have developed an optical tactile sensor capable of measuring a three-dimensional vector distribution. The principle of this optical tactile sensor will be described with reference to FIG. In this optical tactile sensor, a plurality of red markers 521 and a plurality of blue markers 522 are arranged in two parallel planes having different heights in a marker layer 520 formed of a transparent elastic body. When a force is applied from the outside, the operation of each red marker 521 and each blue marker 522 by the force is photographed by a CCD camera or the like. Based on the movement information of each marker thus obtained, deformation information inside the marker layer 520 when a force is applied to the surface of the elastic body is measured, and the force distribution is reconstructed.

  The surface of the marker layer 520 is taken as the xy plane, the vertical direction is taken as the z axis, and each marker is photographed from the z direction using a CCD camera, thereby measuring the movement of the measurement point when a force is applied as a movement vector in the xy plane direction. To do. In order to reconstruct the force vector distribution from the marker movement information, N × N red markers and blue markers are arranged at different depths inside the marker layer 520 as the measurement points. By obtaining two two-dimensional movement vectors and treating them as different pieces of information, the amount of information is increased to obtain a force vector distribution.

Applications of such an optical tactile sensor include, for example, measurement of pressure distribution applied to a person's buttocks sitting on a seat of a chair, measurement of pressure distribution of a human sleeping on a bed, flooring It can be applied to walking measurement or center-of-gravity sway measurement by using it on the surface, and large area force distribution measurement is performed. Here, when practical application and application of force distribution measurement of a large area by this optical tactile sensor is considered, it becomes a problem to shorten the calculation time for obtaining the force distribution. Has been proposed (for example, see Patent Document 1).
International Publication No. WO2005 / 029027 A1

  As a result of further research to solve the above problems, the present inventor applied force from the outside rather than calculating force distribution using movement information of all markers of the optical tactile sensor. It has been found that if the force-receiving area is determined and the force distribution is calculated using only the movement information of the markers in the area, the calculation time can be greatly reduced.

Means for Solving the Problems and Effects of the Invention

  The optical tactile sensor of the present invention includes a force receiving layer to which a force is applied from the outside, a marker layer having elasticity and translucency provided therein with a plurality of marker groups each including a different type of marker, A sheet that is arranged between a force receiving layer and the marker layer, and when a force is applied to the force receiving layer, the area where the force is applied changes to a brightness corresponding to the magnitude of the force. Layer, and the marker layer is disposed on the opposite side of the force-receiving layer, and based on the imaging result of the imaging device, an imaging device for imaging each marker and the sheet layer in the marker layer, Determination means for determining a power receiving area brighter than a predetermined brightness in the sheet layer, and a marker in the power receiving area determined to be brighter than the predetermined brightness in the determination means Based on the marker movement information determined by the determination means obtained from the imaging result of the imaging device and the determination means for determining the marker used in the calculation for obtaining the force distribution in the force receiving layer among the markers And calculating means for calculating a force distribution in the force receiving layer.

  According to this configuration, the force distribution is calculated based only on the movement information of the marker in the force receiving area corresponding to the area where the force is applied in the force receiving layer. Therefore, compared with the case where the force distribution is calculated based on the movement information of all the markers, the calculation time for obtaining the force distribution can be greatly shortened.

  Further, in the optical tactile sensor of the present invention, a housing that houses the marker layer, the sheet layer, and the imaging device and has a light shielding property, and the force receiving layer that is opposite to the force-receiving layer with respect to the marker layer in the housing And a first light source disposed on the side. According to this configuration, the force receiving area can be accurately determined.

  In the optical tactile sensor of the present invention, the sheet layer includes an elastic member having elasticity and translucency, and a second light source that supplies light into the elastic member, and the elastic member Irregularities may be formed on the surface of the marker layer.

  In the optical tactile sensor of the present invention, the sheet layer may have a printed layer made of a pressure-sensitive paint. According to this configuration, it is not necessary to provide a light source in the sheet layer, so that the manufacturing cost can be reduced.

  In the optical tactile sensor of the present invention, the sheet layer further includes an elastic member having elasticity and translucency, and the printed layer is disposed on a surface of the elastic member opposite to the marker layer. In addition to being disposed, the surface of the elastic member on the same side as the marker layer may be provided with irregularities.

  Moreover, the optical tactile sensor of this invention WHEREIN: The said sheet | seat layer may have the printing layer by stress luminescent paint. According to this configuration, it is not necessary to provide a light source in the sheet layer, so that the manufacturing cost can be reduced.

  In the optical tactile sensor of the present invention, the sheet layer further includes an elastic member having elasticity and translucency, and the printed layer is disposed on a surface of the elastic member opposite to the marker layer. It may be arranged.

  In the optical tactile sensor of the present invention, the sheet layer may have elasticity and translucency, and may have an elastic member manufactured by mixing a pressure sensitive paint or a stress luminescent paint. According to this configuration, since it is not necessary to provide a light source in the sheet layer, the manufacturing cost can be reduced and the manufacturing of the sheet layer is facilitated.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 3 is a diagram showing a configuration of the optical tactile sensor according to the first embodiment of the present invention.

  The optical tactile sensor 1 shown in FIG. 3 is stored in a light-shielding housing 40, a sheet layer 10, a marker layer 20 and a CCD camera 30 housed in the housing 40, and a computer (not shown). And an arithmetic unit 60. The housing 40 is a rectangular parallelepiped box-shaped member formed of a flexible material. Here, in the present embodiment, the upper surface portion 41 of the housing 40 is a force receiving layer, that is, a sensor surface 45 to which a force is applied from the outside. The optical tactile sensor 1 has a white LED 50 disposed on the opposite side of the force receiving layer 10 with respect to the marker layer 20 in the housing 40 and a green LED 51 disposed in the sheet layer 10. Yes.

  The sheet layer 10 is disposed between the upper surface portion 41 of the housing 40 and the marker layer 20. The sheet layer 10 is formed of silicon rubber having elasticity and translucency, and a large number of protrusions 11 are provided on the lower surface (the surface on the marker layer 20 side). Therefore, when a force is applied to the upper surface portion 41 of the housing 40 from the outside, the sheet layer 10 corresponding to the force receiving region is bent, and the protrusion 11 in the region is pressed against the upper surface of the marker layer 20. Deform. Here, as described above, the green LED 51 is arranged in the sheet layer 10, and when a force is applied to the upper surface portion 41 of the housing 40, the force receiving region to which the force is applied is the force region. The brightness changes according to the size of the.

  The marker layer 20 is made of elastic and translucent silicon rubber, and a large number of markers are embedded in the vicinity of the upper end portion thereof. A large number of markers are classified into two types respectively included in two marker groups, and are embedded in portions having different depths. Here, in the present embodiment, the two marker groups include markers having different colors, one marker group includes the red marker 21, and the other marker group includes the blue marker 22. include.

  The CCD camera 30 is disposed in the vicinity of the lower end portion in the housing 40 and photographs the markers 21 and 22 and the sheet layer 10 in the marker layer 20. The CCD camera 30 is a digital camera, that is, a camera that outputs image data as an electrical signal. The photographing apparatus according to the present invention is not limited to a CCD camera, and may be a digital camera using a C-MOS image sensor, for example.

  Here, the marker layer 20 is preferably formed of silicon rubber, but may be formed of other elastic members such as other rubbers and elastomers. In addition, since the marker layer 20 should not be inhibited from being deformed by the embedded marker, each of the markers 21 and 22 is formed of an elastic member (preferably having an elastic constant equivalent to that of the elastic body). More preferably, it is comprised from the same material as the marker layer 20, and in one preferable aspect, it is comprised from what added the pigment | dye to silicon rubber. Further, the material of each marker is not particularly limited as long as each marker is sufficiently small so as not to inhibit the deformation of the marker layer 20. Moreover, each part of the marker layer 20 may constitute a marker. Although the case where the marker layer 20 has two marker groups is shown in the present embodiment, the number of marker groups is not limited.

  Further, as described above, the optical tactile sensor 1 is provided on the upper surface portion 41 of the housing 40 based on the photographing result obtained by the CCD camera 30 when a force is applied to the upper surface portion 41 of the housing 40. It has the calculating part 60 which calculates force distribution. The calculation unit 60 includes a determination unit 61, a determination unit 62, a movement information detection unit 63, and a calculation unit 64.

  The determination unit 61 determines a power receiving area brighter than a predetermined brightness in the sheet layer 10 based on the photographing result by the CCD camera 30. In the optical tactile sensor 1, when an external force is applied to the upper surface portion 41 of the housing 40, the protrusion 11 in the force receiving region is greatly deformed. As a result, the brightness of the force receiving area of the sheet layer 10 becomes brighter than before the force is applied. Here, the determination unit 61 is set with a threshold value used when determining the force-receiving area. That is, in the determination unit 61, an area brighter than a predetermined brightness corresponding to the threshold value is determined as the power receiving area.

  The determination unit 62 determines a marker used for calculation for obtaining a force distribution in the upper surface portion 41 of the housing 40 among the markers in the marker layer 20. That is, the determination unit 62 determines a marker in an area that is determined as a power receiving area brighter than the predetermined brightness by the determination unit 61.

  The movement information detection unit 63 detects movement information related to the marker determined by the determination unit 62 based on the photographing result by the CCD camera 30.

  The calculation unit 64 calculates the force distribution in the upper surface portion 41 of the housing 40 based on the marker movement information detected by the movement information detection unit 63. Here, the calculation unit 64 stores a transfer function for reconstructing the force vector or force vector distribution applied to the upper surface portion 41 of the housing 40 from the movement information of each marker. The transfer function is a function that associates force information applied to the upper surface portion 41 of the housing 40 with movement information of each marker.

  Next, a case where a force is applied to the upper surface portion 41 of the housing 40 will be described with reference to FIG. FIG. 4A is a diagram showing a state in which a force is applied to the upper surface portion 41 of the housing 40. Here, a case where the rectangular member 70 is placed near the center of the upper surface portion 41 of the housing 40 is shown. FIG. 4B is a diagram showing a force receiving region in the state of FIG.

  When the rectangular member 70 is placed near the center of the upper surface portion 41 of the housing 40, a force is applied to the upper surface portion 41 from the lower surface of the rectangular member 70. Here, a force receiving region L (region surrounded by a broken line in FIG. 4B) where force is applied to the upper surface portion 41 of the housing 40 is a region where the rectangular member 70 and the upper surface portion 41 are in contact with each other. It is. Then, the protrusion 11 in the force receiving region L on the lower surface of the sheet layer 10 is pressed against the upper surface of the marker layer 20 and deformed as shown in FIG. At this time, the brightness of the force receiving area L of the sheet layer 10 changes to a brightness according to the magnitude of the force.

  As described above, the determination unit 61 is set with a threshold value used when determining the force receiving region L. Therefore, the determination unit 61 determines that the region brighter than the predetermined brightness corresponding to the threshold, that is, the contact region between the rectangular member 70 and the upper surface portion 41 is the force receiving region L. Then, the determination unit 62 uses the 15 red markers 21 and the 15 blue markers 22 in the force receiving region L among the markers in the marker layer 20 for calculation for obtaining the force distribution. Decide on a marker.

  Thereafter, the movement information detection unit 63 detects movement information related to the 30 markers based on the photographing result of the CCD camera 30. Then, the calculation unit 64 calculates the force distribution on the upper surface portion 41 of the housing 40 based on the movement information. That is, in the optical tactile sensor 1, only the movement information of the 30 markers in the force receiving region L is used to calculate the force distribution on the upper surface portion 41 of the housing 40.

  Next, the large area tactile sensor 101 in which the sensor area is increased will be described with reference to FIGS. FIG. 5A shows a schematic configuration of the optical tactile sensor, and FIG. 5B shows a schematic configuration of the large area tactile sensor. Here, in FIG. 5A and FIG. 5B, illustration of the housing is omitted. In the large-area tactile sensor 101 shown in FIG. 5B, the entire sensor surface and the plurality of CCD cameras are housed in one housing, and the plurality of CCD cameras are connected to one arithmetic unit.

  As shown in FIG. 5, the large area tactile sensor 101 is configured by combining a plurality of the optical tactile sensors 1 described above. The sensor surfaces 145 of the large-area tactile sensor 101 are formed by laying the sensor surfaces 45 in contact with each other so that the sensor surfaces 45 of the plurality of optical tactile sensors 1 are arranged on the same surface. Is done. In FIG. 5, a sensor surface 45 having a rectangular shape in plan view of the optical tactile sensor 1 is illustrated. The shape of the sensor surface 45 of the optical tactile sensor 1 is not limited to a rectangular shape, but the sensor surface 45 of the optical tactile sensor 1 is preferably rectangular when laying a plurality of sensor surfaces. In the present embodiment, the large area tactile sensor 101 having the planar sensor surface 145 is shown, but the sensor surface is not limited to a flat surface, and may be a sensor surface formed of a free curved surface.

  Here, since the large area tactile sensor 101 uses a plurality of CCD cameras 30, it is necessary to integrate image information acquired by the CCD cameras 30. FIG. 6 is a diagram for explaining integration of image information acquired by a plurality of CCD cameras.

  In the large area tactile sensor 101, a plurality of CCD cameras 30 are arranged so that the respective imaging regions partially overlap each other. Then, an image of each shooting area is acquired by the plurality of CCD cameras 30. Then, the image information is integrated by combining the image information from each CCD camera so that the markers in the overlapping shooting area E of the one shooting area A and the other shooting area B coincide with each other.

  In FIG. 6, each imaging region of two CCD cameras is shown. That is, in FIG. 6, the red marker 21 and the blue marker 22 included in the region corresponding to the overlapping imaging region E in the imaging region A, and the red marker 21 and the blue marker included in the region corresponding to the overlapping imaging region E in the imaging region B. The images captured by the two CCD cameras 30 are combined so that the markers 22 coincide with each other.

  FIG. 7 is a diagram showing the imaging areas of the four CCD cameras shown in FIG. Assuming that the imaging areas acquired by the CCD cameras 30 are A, B, C, and D, respectively, the overlapping imaging areas are the areas A and B, the areas A and C, the areas B and D, and the areas C and D, respectively. The image information of each imaging region A, B, C, D is integrated so that E is formed. In FIG. 7, the markers are omitted.

  Here, the basic configuration of the large area tactile sensor 101 is the same as the configuration of the optical tactile sensor 1. That is, even in the large area tactile sensor 101, when a force is applied to the sensor surface 145, the brightness of the force receiving area to which the force is applied becomes a brightness corresponding to the magnitude of the force in the sheet layer. Change. In the large area tactile sensor 101, only the movement information of the marker in the force receiving area in each imaging area of the plurality of CCD cameras is used to calculate the force distribution. As described above, in the large area tactile sensor 101, the number of markers embedded in the marker layer is remarkably increased as compared with the optical tactile sensor 1, so that the force distribution is based only on the movement information of the marker in the force receiving region. By calculating, the calculation time can be greatly shortened.

  Next, a method for reconstructing the force vector distribution applied to the sensor surface will be described with reference to FIG.

  In order to obtain the force vector distribution applied to the sensor surface from the movement information of the marker obtained by the optical tactile sensor 1 (for example, the movement vector which is one of the movement information of the marker), Conversion to information F is required. Conversion from the marker information M to the force information F is performed by the formula F = HM. Here, for the sake of simplicity, a two-dimensional cross section (not considering the y-axis direction in the figure) is considered, but the algorithm is the same even in a general three-dimensional case.

  f is a force vector applied to the sensor surface, and m and n are movement vectors on the CCD element of markers colored Blue and Red, respectively. Consider a finite number of points (4 points in FIG. 8) by appropriate discretization. As described above, each force vector has three components (x, y, and z components). Here, two components (x, z components) are considered. Here, for convenience of explanation, it is assumed that only the x-direction component is observed as shown in the figure.

Force that 8 components f = [fx (1), fx (2), fx (3), fx (4), fz (1), fz (2), fz (3), fz (4)] want to find Distribution,
m = [m (1), m (2), m (3), m (4)], n = [n (1), n (2), n (3), n (4)] are observed It is a movement vector. These m and n are collectively written as x.
That is, x = [m (1), m (2), m (3), m (4), n (1), n (2), n (3), n (4)].
Here, the movement vectors m and n of each marker observed when an x-direction unit force (a force of magnitude 1) is applied at point 1 are collectively written as Mx (1).
That is,
Mx (1) = [m (1), m (2), m (3), m (4), n (1), n (2), n (3), n (4)]
when f = [1,0,0,0,0,0,0,0]

Similarly, the movement vector of each marker observed when a z-direction unit force is applied at point 1 is Mz (1), and each marker observed when an x-direction unit force is applied at point 2 The movement vector is determined in the same manner, such as Mx (2). In the case of a linear elastic body (an elastic body in which a linear addition relation is established between the applied force distribution and displacement. Many elastic bodies satisfy this property), the general force f = [fx (1), fx (2 ), fx (3), fx (4), fz (1), fz (2), fz (3), fz (4)] are given as follows.
X = Mx (1) * fx (1) + Mz (1) * fz (1) + Mx (2) * fx (2) +… + Mz (4) * fz (4)

ただしHmx(x1,x2)は，座標x=x2の表面に加わったx方向単位力による座標x=x1における、mマーカーがある深さでのx方向変位量を表す。同様に、Hnz(x1,x2)は座標x=x2の表面に加わったz方向単位力による座標x=x1における，nマーカーがある深さでのx方向変位量を表す。 If this is written in matrix form, X = H * f. However, H = [Mx (1); Mx (2); ...; Mz (4)]. This H is called a transfer function in the sense that it is a mapping for transmitting the force f to the displacement x.
The following is written for each element.

However, Hmx (x1, x2) represents the amount of displacement in the x direction at the depth where the m marker is located at the coordinate x = x1 by the unit force in the x direction applied to the surface of the coordinate x = x2. Similarly, Hnz (x1, x2) represents the amount of displacement in the x direction at a depth where there is an n marker at a coordinate x = x1 due to a unit force in the z direction applied to the surface of the coordinate x = x2.

ただしImx(1,1)等はinv(H)の各要素であるが，結局のところfx(1)を計算するためのm(1)の寄与を表す。 To find f from the observed x, multiply by the inverse matrix of H. Ie
f = inv (H) * x (Formula 1). However, inv represents an inverse matrix (generally a generalized inverse matrix).
If it writes for every element, it will become like number 2.

However, Imx (1,1) etc. are each element of inv (H), but after all, it represents the contribution of m (1) to calculate fx (1).

  When the unknown is determined by using the inverse matrix of the matrix determined by the transfer function, it is necessary that the number of unknowns exceeds or be equal to the number of observed data. In order to solve this problem, a color-coded two-layer marker group is prepared, and the number of independent observation data is increased to eight by taking the movement of each marker of the two-layer marker group.

  In the general three-dimensional case (in this figure, the y-axis is added), the force vector at one point has 3 degrees of freedom, and the horizontal movement vector of the marker has 2 degrees of freedom. If there are four sampling points as well, the unknowns are f = [fx (1), fy (1), fz (1), fx (2), fy (2), fz (2), fx ( 3), fy (3), fz (3), fx (4), fy (4), fz (4)], while there are twelve values, the observed value is the movement vector m = [mx ( 1), my (1), mx (2), my (2), mx (3), my (3), mx (4), my (4)], which is still insufficient. By observing this in two layers, 16 observation data can be obtained, thereby identifying 12 unknowns. The force vector is estimated from the CCD image using the algorithm as described above. Even with other measurement methods using other markers, only the observed data is different, and by collecting the number of independent observations (information on the behavior of the markers) more than the number of unknowns by means of color coding, the inverse problem can be solved stably. This is the same in that the force vector is estimated.

  Next, a method for obtaining the transfer function (matrix H) will be described. In an elastic body of a certain characteristic shape (for example, a semi-infinite elastic body), the relational expression to be satisfied in the minute region can be satisfied everywhere in the elastic body as a function of the force applied to the surface and the internal displacement. Functions are found in the form of mathematical expressions. In the case of such a shape, the matrix H can be obtained by substituting the coordinates of the elastic body surface (sensor surface) and the internal markers coordinated in a mesh shape into this function.

  Here, it is discovered in the form of a formula that m (x2, y2) = G (f (x1), x2 when surface stress is f (x1) and internal displacement is m (x2, y2) , y2), the function G for finding the internal displacement from the surface stress has been discovered. At this time, for example, the displacement in the marker 2 when a force is applied to the point 1 in FIG. 8 is obtained by m (2, y2) = G (f (1), 2, y2). Where y2 is the marker depth (known). Depending on the shape of the elastic body, the H matrix can be obtained using the above mathematical formula by assuming that the elastic body shape is a semi-infinite elastic body.

  As described above, in the optical tactile sensor 1 according to the present embodiment, the force distribution is calculated based only on the movement information of the marker in the force receiving area where the force is applied on the sensor surface. Therefore, compared with the case where the force distribution is calculated based on the movement information of all the markers, the calculation time for obtaining the force distribution can be greatly shortened. This is particularly effective in a large area tactile sensor 101 in which a plurality of optical tactile sensors 1 are combined.

  Next, an optical tactile sensor 201 according to a second embodiment of the present invention will be described with reference to FIG. FIG. 9 is a diagram showing a configuration of an optical tactile sensor according to the second embodiment of the present invention.

  The optical tactile sensor 201 of the present embodiment is greatly different from the optical tactile sensor 1 according to the first embodiment in that the sheet layer 210 of the optical tactile sensor 201 has elasticity and translucency. It is the point which has the printing layer 212 by the pressure sensitive coating material arrange | positioned on the surface on the opposite side to the marker layer 20 of the member 211 and the elastic member 211. Here, a protrusion 211 a is formed on the surface of the elastic member 211 on the same side as the marker layer 20. The pressure-sensitive paint changes its color to green when force is applied. According to this configuration, it is not necessary to provide a light source in the sheet layer, so that the manufacturing cost can be reduced.

  Next, an optical tactile sensor 301 according to a third embodiment of the present invention will be described with reference to FIG. FIG. 10 is a diagram showing a configuration of an optical tactile sensor according to the third embodiment of the present invention.

  The optical tactile sensor 301 according to the present embodiment differs greatly from the optical tactile sensor 1 according to the first embodiment in that the sheet layer 310 of the optical tactile sensor 301 has elasticity and translucency. This is a point that includes a member 311 and a printed layer 312 made of a stress luminescent paint disposed on the surface of the elastic member 311 opposite to the marker layer 20. In addition, the stress luminescent paint changes its color to green when force is applied. According to this configuration, it is not necessary to provide a light source in the sheet layer, so that the manufacturing cost can be reduced.

  Next, an optical tactile sensor 401 according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 11 is a diagram showing a configuration of an optical tactile sensor according to the fourth embodiment of the present invention.

  The optical tactile sensor 401 according to the present embodiment is greatly different from the optical tactile sensor 1 according to the first embodiment in that the sheet layer 410 of the optical tactile sensor 401 has elasticity and translucency. The pressure-sensitive paint or the stress-light-emitting paint is made of a mixed material. According to this configuration, since it is not necessary to provide a light source in the sheet layer, the manufacturing cost can be reduced and the manufacturing of the sheet layer is facilitated.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims. For example, in the first embodiment described above, the green LED is arranged in the sheet layer, and the red marker and the blue marker are embedded in the marker layer, but the combination of these colors can be changed. It is. That is, for example, a red LED may be disposed in the sheet layer, and a blue marker and a green marker may be embedded in the marker layer.

  Further, in the second and third embodiments described above, the sheet layer has the elastic member and the printing layer, but does not have the elastic member, and only the printing layer made of the pressure-sensitive paint or the stress luminescent paint. You may have.

It is a figure which shows force vector distribution which arises between a tactile sensor and a contact target. The principle figure of an optical tactile sensor is shown, the upper figure is a top view of a transparent elastic body, and the lower figure is a side view of a transparent elastic body. It is a figure which shows the structure of the optical tactile sensor which concerns on the 1st Embodiment of this invention. FIG. 4A is a diagram showing a state in which a force is applied to the upper surface portion 41 of the housing 40. FIG. 4B is a diagram showing a force receiving region in the state of FIG. FIG. 5A shows a schematic configuration of the optical tactile sensor, and FIG. 5B shows a schematic configuration of the large area tactile sensor. It is a figure for demonstrating integration of the image information acquired by the several CCD camera. It is a figure which shows the imaging area of four CCD cameras shown in FIG. It is a figure explaining the movement of the force vector concerning a sensor surface, and a marker. It is a figure which shows the structure of the optical tactile sensor which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the optical tactile sensor which concerns on the 3rd Embodiment of this invention. It is a figure which shows the structure of the optical tactile sensor which concerns on the 4th Embodiment of this invention.

Explanation of symbols

1, 201, 301, 401 Optical tactile sensor 10, 210, 310, 410 Sheet layer 20 Marker layer 21 Red marker 22 Blue marker 30 CCD camera 40 Housing 50 White LED
51 Green LED
60 arithmetic unit 61 determination unit 62 determination unit 63 movement information detection unit 64 calculation unit 101 large area tactile sensor

Claims (8)

A power receiving layer to which force is applied from the outside,
A marker layer having elasticity and translucency, in which a plurality of marker groups each including different types of markers are provided; and
It is arranged between the force receiving layer and the marker layer, and when a force is applied to the force receiving layer, the area where the force is applied changes to brightness according to the magnitude of the force. A sheet layer;
An imaging device that is disposed on the opposite side of the force-receiving layer with respect to the marker layer, and that images each marker in the marker layer and the sheet layer;
Determination means for determining a power receiving area brighter than a predetermined brightness in the sheet layer, based on a photographing result by the photographing apparatus;
Marker used for calculation for obtaining a force distribution in the force receiving layer among the markers in the marker layer, which is in the region determined to be a force receiving region brighter than a predetermined brightness in the determining means A determination means for determining
An optical tactile sensor comprising: a calculating unit that calculates a force distribution in the force receiving layer based on marker movement information determined by the determining unit obtained from a photographing result of the photographing device. . A housing that is formed of a light-shielding and flexible material and that houses the marker layer, the sheet layer, and the imaging device, and one side surface of which is the force-receiving layer;
The optical tactile sensor according to claim 1, further comprising a first light source disposed on the opposite side of the force-receiving layer with respect to the marker layer in the housing. The sheet layer is
An elastic member having elasticity and translucency;
A second light source for supplying light into the elastic member,
3. The optical tactile sensor according to claim 1, wherein the surface of the elastic member on the marker layer side is uneven. 4.   The optical tactile sensor according to claim 1, wherein the sheet layer has a printed layer made of a pressure-sensitive paint. The sheet layer further includes an elastic member having elasticity and translucency,
The printed layer is disposed on a surface of the elastic member opposite to the marker layer, and unevenness is formed on the surface of the elastic member on the same side as the marker layer. Item 5. The optical tactile sensor according to Item 4.   The optical tactile sensor according to claim 1, wherein the sheet layer has a printed layer made of a stress luminescent paint. The sheet layer further includes an elastic member having elasticity and translucency,
The optical tactile sensor according to claim 6, wherein the printed layer is disposed on a surface of the elastic member opposite to the marker layer.   3. The optical type according to claim 1, wherein the sheet layer has elasticity and translucency, and has an elastic member manufactured by mixing a pressure-sensitive paint or a stress luminescent paint. 4. Tactile sensor.

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