JP7081793B2 - Tactile sensor - Google Patents

Description

The present invention relates to a tactile sensor.

The tactile sensor detects the contact position and / or the contact force of the contact object. So far, pressure-sensitive conductive rubber whose impedance changes according to the applied pressure has been used for the tactile sensor (for example, Patent Document 1). In this case, the tactile sensor detects the contact position and / or the contact force of the contact object from the change in the impedance of the pressure-sensitive conductive rubber in response to the pressing force.

Japanese Unexamined Patent Publication No. 2008-256401

In the tactile sensor described in Patent Document 1, the impedance changes due to the change in the electric conductivity of the pressure-sensitive conductive rubber. However, in general, the change in impedance of the pressure-sensitive conductive rubber is relatively small, so that the contact of the contact object with the tactile sensor cannot be measured with high accuracy.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a tactile sensor capable of measuring contact of a contact object with high accuracy.

The tactile sensor according to the present invention includes a detection unit and a measurement unit. The detection unit has a first conductor and a second conductor. A plurality of electrodes are provided on the first conductor. The second conductor faces the first conductor. The measuring unit measures the contact of the contact object with at least one of the first conductor and the second conductor based on the potential of the electrode.

In certain embodiments, the first conductor is larger than the second conductor, and the second conductor is disposed facing a portion of the region of the first conductor.

In certain embodiments, the second conductor is connected to a power source.

In one embodiment, the measuring unit includes a potential measuring unit and a multiplexer. The potential measuring unit measures the potential of the electrode. The multiplexer sequentially switches the connection between the electrode and the potential measuring unit.

In certain embodiments, the measurement unit further includes a signal processing unit that measures the contact of the contact object based on the potential of the electrode.

According to the present invention, the contact of a contact object with a tactile sensor can be measured with high accuracy.

It is a schematic diagram which shows the embodiment of the tactile sensor by this invention. It is a schematic diagram for demonstrating that the tactile sensor of this embodiment measures the contact of a contact object. (A) is a schematic diagram showing a tactile sensor and a display device of the present embodiment, and (b) is a schematic diagram of a display device displaying the measurement result of the tactile sensor. (A) to (c) are schematic diagrams for explaining the generation of the mesh element corresponding to the detection unit. It is a schematic diagram which shows the tactile sensor of this embodiment. It is a graph which shows the time change of the electrode potential measured by the tactile sensor of this embodiment. It is a schematic diagram which shows the tactile sensor of this embodiment. It is a graph which shows the error between the contact position and the pushing force application position measured by the tactile sensor of this embodiment. It is a graph which shows the change of the contact potential with respect to the contact force in the tactile sensor of this embodiment. (A) and (b) are schematic graphs for explaining the determination of contact force. It is a schematic diagram which shows an example of the detection part in the tactile sensor of this embodiment. (A) to (c) are schematic views which show the manufacturing method of the detection part in the tactile sensor of this embodiment.

Hereinafter, embodiments of the tactile sensor according to the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments.

First, an embodiment of the tactile sensor 100 according to the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of the tactile sensor 100 of the present embodiment. The tactile sensor 100 measures contact with a contact object.

The tactile sensor 100 includes a detection unit 110 and a measurement unit 120. The detection unit 110 detects the contact of a contact object with the detection unit 110. The measuring unit 120 measures the contact of the contact object with the detecting unit 110 based on the detection result of the detecting unit 110.

Here, the contact material does not have to be held at a specific potential. Alternatively, the contact object may be a member held at a specific voltage. For example, the contact object may be held at the same potential as the ground potential.

The contact object may come into contact with the detection unit 110 in a relatively narrow area. For example, the contact area between the contact object and the detection unit 110 may be 1 mm ² . Alternatively, the contact object may come into contact with the detection unit 110 in a relatively wide area. For example, the ratio of the contact area of the contact object to the surface area of the detection unit 110 may be 80% or more. Further, a plurality of contact objects may come into contact with the detection unit 110.

It is preferable that at least a part of the detection unit 110 is deformed when the contact object comes into contact with the detection unit 110. Therefore, it is preferable that at least a part of the detection unit 110 has flexibility.

The detection unit 110 has a first conductor 112 and a second conductor 114. For example, both the first conductor 112 and the second conductor 114 are in the form of a sheet. It is preferable that at least one of the first conductor 112 and the second conductor 114 has flexibility.

The electric conductivity of the first conductor 112 and the second conductor 114 is preferably 10 ^-5 S / m or more. For example, the electrical conductivity of the first conductor 112 and the second conductor 114 may be ^{106 S / m or more, 5 × 10 6 S} / m or more, and 10 ⁷ S / m. It may be the above. Typically, the first conductor 112 and the second conductor 114 are preferably formed from a general material having an electric conductivity of ¹⁰⁸ S / m or less. The electric conductivity of the second conductor 114 is preferably higher than that of the first conductor 112.

The first conductor 112 and the second conductor 114 are arranged so as to overlap each other. In FIG. 1, the sizes of the first conductor 112 and the second conductor 114 are substantially the same, but the sizes of the first conductor 112 and the second conductor 114 may be different. The size of the main surface of the first conductor 112 may be larger than the size of the main surface of the second conductor 114. Alternatively, the size of the main surface of the first conductor 112 may be smaller than the size of the main surface of the second conductor 114.

The first conductor 112 is provided with a plurality of electrodes 112a. For example, the electrode 112a is preferably provided along the outer circumference of the first conductor 112.

In FIG. 1, three electrodes 112a are provided on the first conductor 112. However, the number of electrodes 112a provided on the first conductor 112 is preferably 3 or more, and more preferably 10 or more. On the other hand, in order to avoid excessively complicated measurement, the number of electrodes 112a provided on the first conductor 112 is preferably 100 or less.

The second conductor 114 is connected to the power source D. For example, the power source D is a DC power source.

The second conductor 114 faces the first conductor 112. The first conductor 112 and the second conductor 114 are preferably arranged so that one main surface of the first conductor 112 and one main surface of the second conductor 114 face each other.

In the tactile sensor 100, the contact object comes into contact with at least one of the first conductor 112 and the second conductor 114. For example, the contact material comes into contact with the first conductor 112 or the second conductor 114. Alternatively, the contact material comes into contact with both the first conductor 112 and the second conductor 114.

For example, a contact is a part of the human body. Typically, a human finger comes into contact with at least one of the first conductor 112 and the second conductor 114. Alternatively, a portion other than the human hand may come into contact with at least one of the first conductor 112 and the second conductor 114. Alternatively, the contact object may be a machine (eg, a robot).

Alternatively, the first conductor 112 or the second conductor 114 may be part of a contact. For example, a part of the human body may be the first conductor 112 or the second conductor 114.

The plurality of electrodes 112a are connected to the measuring unit 120 via the wiring 112b. The measuring unit 120 measures the potential of the electrode 112a. The measuring unit 120 measures the contact of the contact object based on the potentials of the plurality of electrodes 112a. The measuring unit 120 preferably measures all the potentials of the plurality of electrodes 112a, but may measure the potentials of only a part of the plurality of electrodes 112a.

For example, the measuring unit 120 measures the position where the contact object contacts at least one of the first conductor 112 and the second conductor 114. In addition, in this specification, a position where a contact object comes into contact with at least one of the first conductor 112 and the second conductor 114 may be described as a contact position. Typically, the contact is in contact with one of the first conductor 112 and the second conductor 114 at any position in the overlapping region of the first conductor 112 and the second conductor 114.

Alternatively, the measuring unit 120 measures the force with which the contact object comes into contact with at least one of the first conductor 112 and the second conductor 114. In addition, in this specification, a force applied by a contact object to at least one of a first conductor 112 and a second conductor 114 may be described as a contact force.

When the measuring unit 120 measures the potential of the electrode 112a, it is preferable that one of the electrodes 112a is grounded. By grounding one of the electrodes 112a, it is possible to increase the change in the potential of the electrode 112a when a contact object comes into contact with the ground. However, none of the electrodes need to be grounded. For example, one of the electrodes may be connected to a power source that exhibits a particular voltage.

Typically, when the detection unit 110 comes into contact with the contact object, the first conductor 112 and the second conductor 114 come into contact with each other. However, even when the detection unit 110 comes into contact with the contact object, the first conductor 112 and the second conductor 114 do not have to come into contact with each other.

The tactile sensor 100 of the present embodiment preferably further includes a spacer 130. The spacer 130 is arranged between the first conductor 112 and the second conductor 114. Due to the spacer 130, the first conductor 112 and the second conductor 114 do not come into contact with each other before the contact objects come into contact with each other. The spacer 130 is formed of an insulating material. For example, the electrical conductivity of the spacer 130 is ^10-6 S / m or less. Typically, the spacer 130 is preferably formed from a common material having an electrical conductivity of ^10-18 S / m or higher.

The tactile sensor 100 does not have to include the spacer 130. For example, at least one of the first conductor 112 and the second conductor 114 may be laterally supported. Alternatively, neither the first conductor 112 nor the second conductor 114 need to be fixed at a specific position. Even when the first conductor 112 and the second conductor 114 are simply overlapped without sandwiching the spacer 130, the contact material comes into contact with at least one of the first conductor 112 and the second conductor 114. Therefore, the potential of the electrode 112a is changed.

When the detection unit 110 comes into contact with the contact object, the positional relationship between the first conductor 112 and the second conductor 114 changes, and the potential of the electrode 112a of the first conductor 112 changes. For example, the potential of the electrode 112a of the first conductor 112 changes according to the contact position and / or the contact force of the contact object with respect to the detection unit 110. By measuring the potential of the electrode 112a by the measuring unit 120, the contact of the contact object with the detecting unit 110 can be measured.

According to the tactile sensor 100 of the present embodiment, the contact of the contact object is measured according to the positional relationship between the first conductor 112 and the second conductor 114. Therefore, the contact of the contact object can be measured with high accuracy. Therefore, in the tactile sensor 100 of the present embodiment, the first conductor 112 and the second conductor 114 do not have to have pressure sensitivity. However, it goes without saying that the first conductor 112 and the second conductor 114 may have pressure sensitivity.

FIG. 2 is a schematic diagram for explaining that the tactile sensor 100 of the present embodiment measures the contact of the contact object T. As shown in FIG. 2, the contact object T comes into contact with the detection unit 110 of the tactile sensor 100. Here, the contact object T is a human finger.

When the contact object T comes into contact with the second conductor 114 of the detection unit 110, the second conductor 114 is deformed and the second conductor 114 comes into contact with the first conductor 112. As a result, the electrode 112a is electrically connected to the power source D via the second conductor 114, and the potential of the electrode 112a changes. The measuring unit 120 measures the potential of the electrode 112a. For example, the measuring unit 120 measures the contact position and / or the contact force based on the potential of the electrode 112a.

In the tactile sensor 100 of the present embodiment, the potential of the electrode 112a changes according to the positional relationship between the first conductor 112 and the second conductor 114 facing each other, and the measuring unit 120 is based on the potential of the electrode 112a. The contact of the contact object T is measured. Therefore, the contact of the contact object T with the tactile sensor 100 can be measured with high accuracy. For example, the tactile sensor 100 can measure not only the contact position but also the contact force distribution.

In the tactile sensor 100 shown in FIGS. 1 and 2, the first conductor 112 provided with the electrode 112a is arranged vertically below the second conductor 114, but the present invention is not limited thereto. The second conductor 114 may be arranged vertically below the first conductor 112.

Further, in the tactile sensor 100 shown in FIGS. 1 and 2, the power supply D is arranged separately from the measuring unit 120, but the present invention is not limited thereto. The power supply D may be integrated with the measuring unit 120.

Further, in the tactile sensor 100 shown in FIGS. 1 and 2, the power supply D is connected to the second conductor 114 instead of the first conductor 112 provided with the electrode 112a, but the present invention is limited thereto. Not done. The power supply D may be connected to the first conductor 112 provided with the electrode 112a, and the second conductor 114 may be grounded.

It is preferable that the measurement result obtained by measuring the contact of the contact with the tactile sensor 100 is displayed. For example, the measurement result of the tactile sensor 100 is displayed on the display device. In this case, it is preferable that the display device 210 displays the contact position and the contact force as the measurement result.

FIG. 3A is a schematic view showing the tactile sensor 100 and the display device 210 of the present embodiment. The display device 210 is connected to the tactile sensor 100. Specifically, the display device 210 is connected to the measurement unit 120 of the tactile sensor 100. The display device 210 displays the measurement result of measuring the contact of the contact object by the tactile sensor 100.

FIG. 3B is a schematic diagram showing a display device 210 that displays the measurement result of the tactile sensor 100. The display device 210 displays the measurement result of the tactile sensor 100. The display device 210 displays an image of the detection unit 110. For example, the image of the detection unit 110 can be generated by capturing the image of the detection unit 110.

The display device 210, together with the detection unit 110, displays an image showing the contact position Tp in which the detection unit 110 and the contact object are in contact with each other. Here, the contact position Tp is located substantially in the center of the detection unit 110.

Further, it is preferable that the display device 210 displays an image showing the contact force together with the detection unit 110 and the contact position Tp. Here, the display device 210 displays different colors according to the magnitude of the contact force on the tactile sensor 100. Therefore, the display device 210 may display the contact force distribution on the tactile sensor 100 based on the measurement result of the tactile sensor 100. The display device 210 may display the potential distribution on the tactile sensor 100 based on the measurement result of the tactile sensor 100.

As described above with reference to FIGS. 1 and 2, in the tactile sensor 100, the measuring unit 120 can measure the contact position and / or the contact force between the contact object and the detection unit 110 from the potential of the electrode 112a. The measuring unit 120 measures the contact position and / or the contact force from the potential of the electrode 112a using the conversion table.

The conversion table is obtained by simulation. The conversion table is represented in matrix format. In the simulation, it is input that a contact potential of an arbitrary magnitude is generated at an arbitrary contact position of the detection unit 110, and the potential of the electrode 112a at that time is output. By utilizing the relationship between the input indicating the contact position and the contact potential and the output indicating the potential of the electrode 112a, the measuring unit 120 can measure the contact position and the contact potential of the contact object based on the potential of the electrode 112a.

Next, the relationship between the input showing the contact potential of an arbitrary magnitude at the arbitrary contact position in the detection unit 110 and the output showing the potential of the electrode 112a will be described.

First, the detection unit 110 is converted into data. The data conversion of the detection unit 110 may be performed by imaging the detection unit 110.

Here, data conversion of the detection unit 110 will be described with reference to FIG. 4 (a) to 4 (c) are schematic views for explaining the data conversion of the detection unit 110.

First, as shown in FIG. 4A, the detection unit 110 is prepared. Here, the detection unit 110 may have the first conductor 112 and the second conductor 114 overlapped with each other as shown in FIGS. 1 and 2. Alternatively, as the detection unit 110, only the first conductor 112 provided with the electrode 112a may be prepared.

Next, as shown in FIG. 4B, the image data of the detection unit 110 is generated, and the electrode 112a is specified on the image data. The display device can display the image of the detection unit 110 based on the image data of the detection unit 110.

For example, the image data of the detection unit 110 can be generated by taking an image of the detection unit 110. In this case, the image capture of the detection unit 110 is performed so that the image data includes the data corresponding to the electrode 112a. The imaging may be performed in a state where the first conductor 112 and the second conductor 114 of the detection unit 110 are overlapped with each other. Alternatively, the imaging may be performed by the first conductor 112 alone without overlapping the second conductor 114.

Next, as shown in FIG. 4C, a plurality of mesh elements m are assigned to the detection unit 110 on the image data. The mesh element m is three-dimensionally assigned to the image of the detection unit 110.

Then, by simulation, a contact potential of an arbitrary size is input at an arbitrary position of the mesh element m assigned to the image of the detection unit 110, and the potential of the electrode 112a is obtained as an output. The relationship between the input and the output is obtained according to Laplace's equation according to the potential distribution.

The Laplace equation that the potential distribution follows is expressed by Eq. (1).

Here, σ indicates an electric conductivity and u indicates an electric potential. Based on the shape of the detection unit 110, the above equation (1) is formulated by the finite element method to form simultaneous equations. Here, it is assumed that a specific input potential φ _j is input to a specific mesh element m assigned to the detection unit 110. From this input potential φ _j , the potential of each mesh element m can be obtained by solving the above equation (1) by the finite element method. Therefore, the potential distribution of the detection unit 110 can be obtained from the input potential φ _j . Strictly speaking, the potential of each mesh element m changes not only with the input potential φ _j but also with the grounded electrode of the electrodes 112a.

In the tactile sensor 100 of the present embodiment, the potential of the electrode 112a of the detection unit 110 is measured. Therefore, here, attention is paid to the output potential u _i of the electrode 112 a obtained with respect to the input potential φ _j . Here, j represents the number of mesh elements m in the image data, and i represents the product of the number of electrodes 112a and the number of grounded electrodes among the electrodes 112a. From the calculation result at this time, the relationship of the output potential u _i with respect to the input potential φ _j can be expressed by the matrix J of i rows and j columns, and the elements J _{i and j} of the matrix J are as shown in equation (2). Can be represented.

In equation (2), M represents the product of the number of electrodes and the number of voltage application patterns, and K represents the number of mesh elements. The voltage application pattern indicates a pattern in which a voltage for grounding a specific electrode among the electrodes is applied. It should be noted here that in Eq. (2), the elements J _{i and j} of the matrix J are functions of the potential u and the input potential φ _j , but not the function of the electrical conductivity σ.

It is preferable that all the electrodes of the electrodes 112a are sequentially grounded. For example, when the number of electrodes 112a is 16, the number of voltage application patterns is preferably 16. In this case, even if the configuration of the detection unit 110 is the same, measurement can be performed with higher accuracy. However, only one of the electrodes 112a may be grounded.

From the above description up to Eq. (2), the relationship between δu and δφ can be expressed as Eq. (3) using the matrix J.

Here, the equation (3) is an order problem of obtaining the output δu from the input δφ. Therefore, if the equation (4), which is the inverse problem of the equation (3), is solved, the input δφ can be obtained from the output δu.

However, since the matrix J is not regular, the inverse matrix J ^-1 of the matrix J cannot be obtained. Therefore, instead of the inverse matrix J ^{- 1} , Tihonov's regularization method, which approximates the inverse matrix J-1, is used. According to Tihonov's regularization method, it is known that the inverse matrix J ^-1 can be rewritten as in Eq. (5).

In equation (5), α is a regularization parameter. Using equation (5), equation (4) can be rewritten as in equation (6).

In the formula (6), Q is expressed as the formula (7) or the formula (8).

As described above, the input δφ can be obtained from the output δu. It should be noted that the processing up to this point can be performed by simulation.

The measuring unit 120 shown in FIGS. 1 to 3 measures the potential of the electrode 112a. By using the measurement result of the potential of the electrode 112a and the equation (6), the contact potential associated with the contact of the contact object can be measured by the detection unit 110.

As described above, it is preferable that the tactile sensor 100 switches the grounded electrode among the plurality of electrodes 112a every hour. In this case, the measuring unit 120 preferably includes a multiplexer.

FIG. 5 is a schematic view showing the tactile sensor 100 of the present embodiment. As described above, the tactile sensor 100 includes a detection unit 110 and a measurement unit 120.

The detection unit 110 has a first conductor 112 provided with an electrode 112a and a second conductor 114. Here, 16 electrodes 112a are provided at the end of the first conductor 112 along the outer circumference of the first conductor 112. Further, here, the first conductor 112 is larger than the second conductor 114, and the second conductor 114 is arranged so as to face a part of the region of the first conductor 112.

The measuring unit 120 includes a potential measuring unit 122, a signal processing unit 124, and a multiplexer 126. The potential measuring unit 122 measures the potential of the electrode 112a.

The signal processing unit 124 calculates the contact potential from the potential of the electrode 112a. Typically, the signal processing unit 124 includes a processor. For example, the processor is a central processing unit (CPU), and the signal processing unit 124 is mounted on a computer.

The multiplexer 126 connects to a plurality of electrodes 112a and ground. The multiplexer 126 switches and connects the plurality of electrodes 112a to the ground. Therefore, the multiplexer 126 can switch the grounded electrode among the plurality of electrodes 112a.

FIG. 6 is a graph showing the time change of the potential measured by the tactile sensor 100 shown in FIG. Here, the electrodes to be grounded are switched for each section. One compartment is, for example, approximately 0.8 ms.

For example, when the first electrode is grounded from 0 seconds to about 0.8 milliseconds, the potential of the first electrode becomes substantially zero, and the second electrode to the 16th electrode show a predetermined potential. Next, when the time changes from about 0.8 ms to about 1.6 ms, the potential of the second electrode becomes almost zero, and the first electrode, the third electrode to the 16th electrode have a predetermined potential. show. The grounded electrodes are switched approximately every 0.8 ms, and all of the 1st to 16th electrodes are grounded once in a cycle of approximately 13 ms. As described above, the potentials of the plurality of electrodes 112a can be measured.

In the above description with reference to FIG. 5, while a multiplexer is provided between the plurality of electrodes 112a and the ground, the electrodes 112a and the signal processing unit 124 are directly connected to each other. Not limited. The electrode 112a and the signal processing unit 124 do not have to be directly connected.

Next, the tactile sensor 100 of the present embodiment will be described with reference to FIG. 7. FIG. 7 is a schematic diagram of the tactile sensor 100 of the present embodiment. The tactile sensor 100 shown in FIG. 7 is the tactile sensor described above with reference to FIG. 5, except that the measuring unit 120 further includes a multiplexer 128 in addition to the potential measuring unit 122, the signal processing unit 124, and the multiplexer 126. It has the same configuration as 100. Therefore, duplicate description is omitted to avoid redundancy.

The measuring unit 120 further includes a multiplexer 128 in addition to the potential measuring unit 122, the signal processing unit 124, and the multiplexer 126. The multiplexer 128 connects a plurality of electrodes 112a to the potential measuring unit 122. The multiplexer 128 is connected to the potential measuring unit 122 via an analog-to-digital conversion circuit.

The multiplexer 128 switches and connects the plurality of electrodes 112a and the signal processing unit 124. The potential measuring unit 122 measures the potentials of the plurality of electrodes 112a in order for each time. Therefore, the multiplexer 128 can switch the electrode connected to the potential measuring unit 122 among the plurality of electrodes 112a.

In this case, the potential measuring unit 122 may measure the potentials of the plurality of electrodes 112a for each time, and may not measure the potentials of the plurality of electrodes 112a at the same time. Therefore, the potential measuring unit 122 only needs to have one potential measuring element, and the cost of the potential measuring unit 122 can be reduced.

Here, with reference to FIG. 8, an error between the contact position and the pressing force applied position measured by the tactile sensor 100 of the present embodiment will be described. FIG. 8 is a schematic diagram showing an error between the contact position and the pressing force applied position measured by the tactile sensor 100 of the present embodiment. Here, the dimensions of the detection unit 110 were 20 mm × 20 mm. Further, a pushing force was applied to 25 points of the detection unit 110.

In FIG. 8, ● indicates a pressing force applying position where the pressing force is applied to the detection unit 110, and × indicates a contact position measured by the tactile sensor 100 of the present embodiment. According to the tactile sensor 100 of the present embodiment, the difference between the contact position and the pressing force application position was about 0.76 mm.

In general, as a result of measuring the difference between the contact position and the pressing force application position with a tactile sensor using pressure-sensitive conductive rubber, it is known that the difference between the contact position and the pressing force application position is on the order of several milliorders. There is. From this, it was shown that the tactile sensor 100 of the present embodiment can measure the contact with the tactile sensor 100 with high accuracy.

The tactile sensor 100 preferably measures not only the contact position but also the contact force. As described above, the contact potential can be measured from the potential of the electrode 112a. Therefore, the contact force can be measured based on the potential of the electrode 112a from the relationship between the contact potential and the contact force.

The tactile sensor 100 of the present embodiment measures the contact force from the contact potential. The measuring unit 120 (FIGS. 1 to 3) can measure the contact force from the potential of the electrode 112a using the conversion table.

The conversion table shows the relationship between the potential of the electrode 112a and the contact force. The conversion table is obtained by an experiment using the tactile sensor 100. Here, a metal piece with a force sensor attached was used as a contact object. The pressing force applied to the metal piece was increased or decreased 5 times from 0N to 18N, and the potential of the electrode was measured. The potential of the electrode was converted into a contact potential.

Hereinafter, the relationship between the contact potential and the contact force will be described with reference to FIG. FIG. 9 is a graph showing the relationship between the contact force and the contact potential in the tactile sensor 100 of the present embodiment.

FIG. 9 shows a solid line expressing the relationship between the contact force and the contact potential obtained in the experiment by a regression equation. As shown in FIG. 9, the contact potential gradually increased from 0.0005V to 0.0025V in the range where the contact force was 3N to 10N. On the other hand, even if the contact force exceeded 10 N, the contact potential was approximately 0.0025 V, and almost no change in the contact potential was observed. Therefore, here, it was possible to measure that the contact force is 3N to 10N in the range of the contact potential of 0.0005V to 0.002V.

As described above with reference to the equations (1) to (8), the potential distribution of the detection unit 110 can be obtained from the potential of the electrode 112a. Further, as described above with reference to FIG. 9, the potential distribution of the detection unit 110 can be converted into a contact force. However, it is not preferable to simply convert the potential distribution of the detection unit 110 into a contact force.

Hereinafter, the determination of the contact force from the potential distribution of the detection unit 110 will be described with reference to FIG. 10.

FIG. 10A is a schematic graph showing that the potential of the detection unit 110 is simply converted into a contact force. Since the potential of the detection unit 110 changes smoothly from the contact potential, if the potential of the detection unit 110 is simply converted into a force, the force applied to the detection unit 110 is also as shown in FIG. 10A. It will change smoothly as the distance from the contact position increases.

Generally, the potential of the detection unit 110 changes smoothly from the contact position. On the other hand, the force applied to the detection unit 110 does not change smoothly from the contact position. The force applied to the detection unit 110 is applied to a specific range of the detection unit 110. Therefore, it is preferable to obtain the force applied to the detection unit 110 by using a threshold value and converting the value below the threshold value so that it becomes the same as the base value.

FIG. 10B is a schematic graph showing the result of arithmetic processing using a threshold value after converting the potential of the detection unit 110 into a contact force. As shown in FIG. 10B, after simply converting the potential of the detection unit 110 into a force, the contact force (peak value) is converted into a value less than or equal to a predetermined value so as to be the same as the base value. Therefore, a contact force distribution corresponding to an actual pushing force can be obtained. The predetermined value may be, for example, 70%, 80%, or 90%.

The detection unit 110 in the tactile sensor 100 of the present embodiment may be manufactured in various shapes.

FIG. 11 is a schematic diagram showing an example of the detection unit 110 in the tactile sensor 100 of the present embodiment. As shown in FIG. 11, a plurality of spacers 130 may be arranged in parallel in the same direction. As a result, the second conductor 114 is prevented from coming into contact with the first conductor 112 before the contact object comes into contact, and the second conductor 114 comes into contact with the first conductor 112 with the contact of the contact object. As such, the second conductor 114 can be easily deformed.

In the above description with reference to FIGS. 1 to 3 and 11, the first conductor 112 and the second conductor 114 are planar, but the present invention is not limited thereto. At least one of the first conductor 112 and the second conductor 114 may be curved.

Further, either the first conductor 112 or the second conductor 114 may be formed by applying a conductive paint to the object to be measured. Further, the electrode 112a and the first conductor 112 may be adhered to each other via an adhesive.

12 (a) to 12 (d) are schematic views showing a method of manufacturing the detection unit 110 in the tactile sensor of the present embodiment.

First, as shown in FIG. 12 (a), an object to be measured is prepared. Here, the object to be measured is a member that imitates the tip of a human finger.

Next, as shown in FIG. 12B, the conductive paint is applied to the object to be measured. For example, conductive paints contain resins and conductive fillers. For example, the resin is an epoxy resin. The conductive filler also contains conductive carbon or metal oxide. When the conductive paint dries, the conductive paint becomes the first conductor 112.

Next, as shown in FIG. 12 (c), the electrode 112a is attached to the first conductor 112 so as to surround the end of the first conductor 112. The electrode 112a is adhered to the first conductor 112 using a conductive adhesive. The electrode 112a is connected to the measuring unit 120 (FIGS. 1 and 2) via the wiring 112b.

Next, as shown in FIG. 12 (d), the second conductor 114 is adhered so as to overlap the central portion of the first conductor 112. For example, an adhesive may be applied along the outer periphery of the back surface of the second conductor 114, and the second conductor 114 may be attached to the first conductor 112. The detection unit 110 can be manufactured as shown in FIGS. 12 (a) to 12 (d).

The tactile sensor 100 of this embodiment can be applied to various uses. For example, the tactile sensor 100 of the present embodiment may be attached to the hand arm of an industrial robot. Further, the tactile sensor 100 may be used in the tactile detection system of the virtual reality system. The tactile sensor 100 may be used as a user interface of an information input device (for example, a smartphone or a tablet information device). Further, the tactile sensor 100 may be attached to the tip of the artificial hand. Further, the tactile sensor 100 may be attached to a bed or a futon and used to detect a human sleep state.

Further, the tactile sensor 100 of the present embodiment may be used for pressure detection of the worker support system. Further, the tactile sensor 100 may be used for tactile evaluation of a product or a material.

The tactile sensor 100 can also be applied to research applications. For example, the tactile sensor 100 may be used for analysis and elucidation of human tactile function. The tactile sensor 100 may be utilized for motion analysis in medicine or sports. The tactile sensor 100 may also be used as part of a remote diagnosis or remote surgery system. Alternatively, the tactile sensor 100 may be used as part of the game controller.

The embodiments of the present invention have been described above with reference to the drawings (FIGS. 1 to 12). However, the present invention is not limited to the above embodiment, and can be implemented as an embodiment in various embodiments without departing from the gist thereof. In addition, various inventions can be formed by appropriately combining the plurality of components disclosed in the above embodiments. For example, some components may be removed from all the components shown in the embodiments. In order to make the drawings easier to understand, each component is schematically shown, and the number of each component shown may differ from the actual one due to the convenience of drawing. Further, each component shown in the above embodiment is an example, and is not particularly limited, and various modifications can be made without substantially deviating from the effect of the present invention.

The tactile sensor of this embodiment can be applied to various applications.

100 Tactile sensor 110 Detection unit 120 Measurement unit

Claims (5)

A first conductor provided with a plurality of electrodes, and a detection unit having a second conductor separated from the first conductor and facing the first conductor.
Based on the potential of the electrode, the first conductor and the second conductor come into contact with each other due to the contact with at least one of the first conductor and the second conductor . A tactile sensor comprising a measuring unit for measuring contact of the contact object with at least one of the first conductor and the second conductor. The first conductor is larger than the second conductor,
The tactile sensor according to claim 1, wherein the second conductor is arranged so as to face a part of the region of the first conductor. The tactile sensor according to claim 1 or 2, wherein the second conductor is connected to a power source. The measuring unit
A potential measuring unit that measures the potential of the electrode,
The tactile sensor according to any one of claims 1 to 3, further comprising a multiplexer that sequentially switches the connection between the electrode and the potential measuring unit. The tactile sensor according to claim 4, wherein the measuring unit further includes a signal processing unit that measures the contact of the contact object based on the potential of the electrode.

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