Inspection device and inspection method for load distribution sensors

Abstract

To easily and accurately inspect a conductive sheet even when a broken part of the conductive sheet is minute.SOLUTION: An inspection device 20 according to an embodiment includes: a plurality of drive side loop electrodes 11 arranged in parallel within a first surface; a plurality of detection side loop electrodes 12 arranged in parallel in a direction perpendicular to the drive side loop electrodes 11 within a second surface parallel to the first surface; and a conductive sheet 14 provided through an intermediate layer 13 to be deformed according to a pressing force on the second surface. The inspection device for a load distribution sensor drives one of the drive side loop electrodes 11 and the inspection side loop electrodes 12 to detect a signal due to electromagnetic coupling from the other. The inspection device includes: a conductive member 21 arranged so as to cover an electromagnetic coupling part of the drive side loop electrodes 11 and the inspection side loop electrodes 12 on the conductive sheet 14 and has a resistance value lower than that of the conductive sheet 14; and a detection unit 16 that detects a signal due to electromagnetic coupling of the conductive member 21.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inspection apparatus and an inspection method for a load distribution sensor.

Background Art

[0002] Patent Document 1 discloses a pressure distribution detection device that utilizes a change in the degree of electromagnetic coupling due to pressure on a detection surface. This pressure distribution detection device includes a plurality of drive-side loop-shaped wirings and detection-side loop-shaped wirings respectively arranged on opposite surfaces of a substrate, and a cushion material and a conductive sheet provided in sequence on the detection-side loop-shaped wiring. The drive-side loop-shaped wiring and the detection-side loop-shaped wiring are configured to be electromagnetically coupled to each other. By detecting a change in the degree of this electromagnetic coupling, the pressure distribution is detected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As one of the failure modes of such an electromagnetic induction type load distribution sensor, there is fatigue failure of the conductive sheet. When inspecting such a damaged portion of the conductive sheet, since a protective plate is provided substantially over the entire surface of the conductive sheet, it is difficult to detect it visually.

[0005] In addition, since such a load sensor generally has a wide detection surface, if a load is applied to the load distribution sensor in order from the end and the inspection is performed based on the change in the load value, there is a problem that it takes an enormous amount of time. Further, since the damaged portion due to the fatigue failure of the conductive sheet is minute, the change in the load value is small, and it is difficult to find it accurately.

[0006] This invention has been made in view of the above problems, and the object of this invention is to provide an inspection device and inspection method for a load distribution sensor that can perform inspections easily and accurately even when the damaged area of ​​the conductive sheet is minute. [Means for solving the problem]

[0007] A load distribution sensor inspection device according to a first aspect of the present invention includes: a plurality of first loop electrodes arranged in parallel within a first surface; a plurality of second loop electrodes arranged in parallel in a direction perpendicular to the first loop electrodes within a second surface parallel to the first surface on the first surface; and a conductive sheet provided on the second surface via an intermediate layer that deforms according to pressing force, wherein the device drives one of the first loop electrodes and the second loop electrodes and detects a signal from the other due to electromagnetic coupling, and further comprises a conductive member with a lower resistance value than the conductive sheet, arranged on the conductive sheet so as to cover the electromagnetic coupling portion of the first loop electrode and the second loop electrode, and a detection unit for detecting a signal due to the electromagnetic coupling of the conductive member.

[0008] In a load distribution sensor inspection device according to a second aspect of the present invention, the conductive member covers the conductive sheet over a predetermined area.

[0009] In a load distribution sensor inspection device according to a third aspect of the present invention, the conductive member is a conductive member having an area that is substantially equal to or smaller than the measurement area defined by the first loop electrode and the second loop electrode of the load distribution sensor.

[0010] In a load distribution sensor inspection device according to a fourth aspect of the present invention, the conductive member is a conductive member having an area smaller than the measurement area defined by the first loop electrode and the second loop electrode of the load distribution sensor, and the device further comprises a moving mechanism for sliding the conductive member on the measurement area.

[0011] In a load distribution sensor inspection device according to a fifth aspect of the present invention, the conductive member is made of the same material as the conductive sheet and is thicker than the conductive sheet.

[0012] In a load distribution sensor inspection device according to a sixth aspect of the present invention, the conductive member is made of a material with a lower resistance value than the conductive sheet.

[0013] A method for inspecting a load distribution sensor according to a seventh aspect of the present invention includes: a plurality of first loop electrodes arranged in parallel within a first surface; a plurality of second loop electrodes arranged in parallel in a direction perpendicular to the first loop electrodes within a second surface parallel to the first surface on the first surface; and a conductive sheet provided on the second surface via an intermediate layer that deforms in accordance with pressing force, wherein the method drives one of the first loop electrodes and the second loop electrodes and detects a signal from the other due to electromagnetic coupling, and includes the steps of: placing a conductive member with a lower resistance value than the conductive sheet on the conductive sheet so as to cover the electromagnetic coupling portion of the first loop electrode and the second loop electrode; and detecting a signal due to electromagnetic coupling of the conductive member. [Effects of the Invention]

[0014] According to the present invention, even if the damaged area of ​​the conductive sheet is minute, it is possible to perform inspections easily and accurately. [Brief explanation of the drawing]

[0015] [Figure 1] This is a diagram illustrating an inspection device for a load distribution sensor according to an embodiment. [Figure 2] This figure shows an example of applying a load distribution sensor to a treadmill. [Figure 3] This diagram illustrates the schematic configuration of a load distribution sensor. [Modes for carrying out the invention]

[0016] Embodiments of the present invention will be described below with reference to the drawings. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In addition, the same elements are denoted by the same reference numerals in each drawing, and redundant explanations have been omitted where necessary.

[0017] The embodiment relates to an inspection device for an electromagnetic induction type load distribution sensor. First, the schematic configuration of the load distribution sensor will be described with reference to Figure 3. Figure 3 is a diagram illustrating the schematic configuration of the load distribution sensor. In Figure 3, the stacked structure of the load distribution sensor described in Patent Document 1 is partially disassembled and shown.

[0018] As shown in Figure 3, the load distribution sensor 10 includes a drive-side loop electrode 11, a detection-side loop electrode 12, an intermediate layer 13, a conductive sheet 14, a drive unit 15, and a detection unit 16. Multiple drive-side loop electrodes 11 are arranged parallel to each other within a first plane. Multiple detection-side loop electrodes 12 are arranged parallel to each other within a second plane parallel to the first plane. The detection-side loop electrodes 12 are perpendicular to each other with respect to the drive-side loop electrodes 11.

[0019] The drive-side loop electrode 11 and the detection-side loop electrode 12 are arranged, for example, on opposing surfaces of a substrate (not shown). In the example shown in Figure 3, the drive-side loop electrode 11 is located on the back surface of the substrate and the detection-side loop electrode 12 is located on the front surface of the substrate, but they may be arranged in the opposite direction. Furthermore, the arrangement is not limited to the example where the drive-side loop electrode 11 and the detection-side loop electrode 12 are arranged on both sides of a single substrate. For example, two substrates on which the drive-side loop electrode 11 and the detection-side loop electrode 12 are formed may be stacked, or the loop electrodes may be arranged by point-to-point wiring or the like without using a substrate.

[0020] Coil-shaped patterns are formed on the drive-side loop electrode 11 and the detection-side loop electrode 12, respectively, at the intersection points of the loop electrodes. These coil-shaped patterns are configured to be electromagnetically coupled, forming an electromagnetic coupling section 17. The electromagnetic coupling section 17 is arranged in a matrix within the measurement area of ​​the load distribution sensor 10. Various conventional configurations can be applied to the electromagnetic coupling section.

[0021] A conductive sheet 14 is disposed on the detection-side loop electrode 12. The conductive sheet 14 is a film having conductivity and is made of, for example, aluminum foil, copper foil, or the like. As the conductive sheet 14, for example, aluminum foil with a thickness of 0.1 to 0.2 mm can be used. The conductive sheet 14 is provided over substantially the entire measurement region of the load distribution sensor 10.

[0022] Although not shown here, a protective plate is provided over substantially the entire surface of the conductive sheet 14 for the purpose of being directly stepped on during load measurement. As the material of such a protective plate, for example, a waterproof sheet such as tarpaulin can be used. Tarpaulin is a composite sheet in which a fiber cloth is sandwiched between soft synthetic resin films. Also, the protective plate may be formed of an acrylic plate, a polycarbonate plate, or the like.

[0023] An intermediate layer 13 is disposed between the detection-side loop electrode 12 and the conductive sheet 14. When the drive-side loop electrode 11 is provided on the surface of the substrate, the intermediate layer 13 will be disposed between the drive-side loop electrode 11 and the conductive sheet 14. The intermediate layer 13 is a cushioning material that deforms according to the pressing force. The intermediate layer 13 is made of, for example, an insulating material such as urethane foam that does not affect electromagnetic coupling.

[0024] A drive unit 15 is connected to the drive-side loop electrode 11, and a detection unit 16 is connected to the detection-side loop electrode 12. The drive unit 15 sequentially drives the plurality of drive-side loop electrodes 11 with an alternating current. The detection unit 16 sequentially detects changes in the degree of electromagnetic coupling of each electromagnetic coupling unit 17. Note that various conventional configurations can be applied to the drive unit 15 and the detection unit 16.

[0025] In this load distribution sensor 10, when the drive-side loop electrode 11 is driven, an AC electromotive force is induced in the detection-side loop electrode 12 due to the electromagnetic coupling of the electromagnetic coupling unit 17. The magnitude of this electromotive force changes depending on the degree of electromagnetic coupling. The degree of electromagnetic coupling changes depending on the distance between the electromagnetic coupling unit 17 and the conductive sheet 14.

[0026] When a load is applied to the conductive sheet 14 and the conductive sheet 14 approaches the electromagnetic coupling part 17, the current detected from the detection-side loop electrode 12 changes. The load distribution sensor 10 detects the load value and its position by sequentially detecting the currents from multiple detection-side loop electrodes 12.

[0027] Thus, in the load distribution sensor 10, load measurement is performed at the electromagnetic coupling portion 17 between the drive-side loop electrode 11 and the detection-side loop electrode 12. Therefore, the measurement area of ​​the load distribution sensor 10 is defined by the drive-side loop electrode 11 and the detection-side loop electrode 12.

[0028] In such a load distribution sensor 10, if the conductive sheet 14 is damaged due to fatigue failure or the like, a value different from the value that should be detected will be output. The inspection device for the load distribution sensor 10 according to this embodiment detects the location of the damage to the conductive sheet 14.

[0029] Figure 1 illustrates an inspection device for a load distribution sensor 10 according to an embodiment. Figure 1 shows an example where the measurement area of ​​the load distribution sensor 10 is 590 mm in length and 1600 mm in width. As an example, the drive unit 15 and detection unit 16 are concentrated near the center of one of the longer sides of the load distribution sensor 10. Note that the size, shape, and arrangement of these components are not limited to the example shown.

[0030] A conductive member 21 is placed on the load distribution sensor 10. The conductive member 21 is placed on the conductive sheet 14 with a predetermined area so as to cover the electromagnetic coupling portion 17 of the drive-side loop electrode 11 and the detection-side loop electrode 12. In the example shown in Figure 1, a conductive member 21 measuring 500 mm in length and 500 mm in width is used.

[0031] The conductive member 21 has a lower resistance than the conductive sheet 14. For example, if the conductive sheet 14 is made of aluminum foil with a thickness of 0.1 to 0.2 mm, the conductive member 21 can be a metal plate of similar thickness but with a lower resistance than aluminum, such as silver, gold, or copper.

[0032] Furthermore, by using the same material as the conductive sheet 14 for the conductive member 21 and making the thickness of the conductive member 21 greater than that of the conductive sheet 14, it is also possible to make the resistance value of the conductive member 21 smaller than that of the conductive sheet 14. For example, if the conductive sheet 14 is made of aluminum foil with a thickness of 0.1 to 0.2 mm, the conductive member 21 can be a metal plate made of aluminum with a thickness of about 1 to 5 mm, which is thicker than the conductive member 21.

[0033] Since the conductive member 21 has a lower resistance than the conductive sheet 14, it is more susceptible to generating eddy currents due to electromagnetic induction than the conductive sheet 14. Therefore, when the conductive member 21 is positioned to cover the conductive sheet 14, the eddy currents generated in the conductive member 21 at the point of damage to the conductive sheet 14 due to the induced magnetic field generated by passing an alternating current through the coil-shaped pattern of the electromagnetic coupling portion 17 will be greater than the eddy currents generated in the conductive sheet 14 at the points where the conductive sheet 14 is not damaged.

[0034] Due to the difference in the magnitude of these eddy currents, the value of the alternating electromotive force induced at the detection-side loop electrode 12 at the damaged area of ​​the conductive sheet 14 is greater than at the undamaged area. Therefore, the detected value at the damaged area of ​​the conductive sheet 14 is greater than that at the undamaged area of ​​the conductive sheet 14. In other words, the detection unit 16 also functions as a detection unit that detects signals due to electromagnetic coupling of the conductive member 21 in the inspection device 20.

[0035] Here, a method for inspecting the load distribution sensor 10 according to the embodiment will be described. This inspection method includes the steps of placing a conductive member 21 with a lower resistance value than the conductive sheet 14 on the conductive sheet 14 so as to cover the electromagnetic coupling portion 17 of the drive-side loop electrode 11 and the detection-side loop electrode 12, and detecting a signal due to the electromagnetic coupling of the conductive member 21 with the detection unit 16.

[0036] Thus, in this embodiment, instead of actually applying a load to the load distribution sensor 10 to perform the inspection, the inspection can be performed to identify the location of damage to the conductive sheet 14 by utilizing the change in the detected value due to electromagnetic induction of the conductive member 21. By arranging the conductive sheet 14 so as to cover the load distribution sensor 10 and observing the change in the detected value output from the detection unit 16, it becomes possible to perform a simple and accurate inspection even if the damage to the conductive sheet 14 is minute.

[0037] In this embodiment, a conductive member 21 measuring 500 mm in length and 500 mm in width is slid vertically and horizontally across the measurement area of ​​the load distribution sensor 10 to inspect the entire conductive sheet 14 of the measurement area. This makes it possible to identify the location of damage to the conductive sheet 14 across almost the entire measurement area of ​​the load distribution sensor 10 in a short time.

[0038] The size of the conductive member 21 is not particularly limited. For example, it is possible to inspect the entire measurement area at once by using a conductive member 21 that is approximately the same size as the measurement area defined by the drive-side loop electrode 11 and the detection-side loop electrode 12.

[0039] Furthermore, the conductive member 21 may have a smaller area than the measurement area. Since the inspection device 20 uses the change in the detected value due to electromagnetic induction by the conductive member 21 to inspect the location of damage to the conductive sheet 14, the conductive member 21 should cover the conductive sheet 14 with a predetermined area so as to cover a plurality of adjacent electromagnetic coupling parts 17. Alternatively, a strip-shaped conductive member 21 with a length equal to the vertical length of the measurement area of ​​the load distribution sensor 10 may be slid in one direction from one end to the other end of the load distribution sensor 10.

[0040] Furthermore, the shape of the conductive member 21 is not limited to a plate shape. As long as it covers a predetermined area on the conductive sheet 14 in order to measure the change in the detected value due to electromagnetic induction of the conductive member 21, the shape of the conductive member 21 may be cylindrical, prismatic, or the like. In this case, the conductive member 21 can be rotated in the circumferential direction and moved on the load distribution sensor 10.

[0041] The inspection device 20 may also include a moving mechanism for sliding the conductive member 21 over the measurement area of ​​the load distribution sensor 10. The specific structure of the moving mechanism is not particularly limited, but for example, it may be manually moved by an operator, or it may be elastically moved using a spring or the like, or it may be operated by a predetermined actuator.

[0042] The load distribution sensor 10 described above is applied to the treadmill 101 of the walking training device 100. Figure 2 shows an example of applying the load distribution sensor 10 to the treadmill 101. The treadmill 101 is a device that encourages the trainee to walk.

[0043] The treadmill 101 includes a ring-shaped belt 102, as well as pulleys and a motor (not shown). The motor rotates the pulleys, which unchain the ring-shaped belt 102. Trainees performing walking exercises stand on the belt 102 and perform walking movements in accordance with the movement of the belt 102. A load distribution sensor 10 is positioned below the belt 102. The load distribution sensor 10 detects the distribution of the load received from the trainee's feet.

[0044] When inspecting the conductive sheet 14 of such a load distribution sensor 10, a conductive member 21 can be placed on the belt 102 to cover the conductive sheet 14. This makes it possible to inspect the conductive sheet 14 while the load distribution sensor 10 is incorporated into the walking training device 100 by observing the change in the detected value due to electromagnetic induction by the conductive member 21.

[0045] Furthermore, by driving the belt 102, the conductive member 21 positioned on the belt 102 can be moved along with the belt 102 on the load distribution sensor 10. In this case, there is no need to provide a separate moving mechanism for sliding the conductive member 21.

[0046] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0047] 10. Load distribution sensor 11 Drive-side loop electrode 12 Detection-side loop electrode 13. Middle Class 14 Conductive Sheet 15 Drive unit 16 Detection unit 17 Electromagnetic coupling section 20 Inspection equipment 21 Conductive member 100 Walking Training Devices 101 Treadmill 102 belt

Claims

1. An inspection device for a load distribution sensor, comprising: a plurality of first loop electrodes arranged parallel to each other within a first surface; a plurality of second loop electrodes arranged parallel to each other in a direction perpendicular to the first loop electrodes within a second surface parallel to the first surface; and a conductive sheet provided on the second surface via an intermediate layer that deforms according to the pressing force, wherein one of the first loop electrodes and the second loop electrodes is driven and a signal is detected from the other by electromagnetic coupling, A conductive member with a lower resistance value than the conductive sheet is placed on the conductive sheet so as to cover the electromagnetic coupling portion of the first loop electrode and the second loop electrode, A detection unit for detecting signals due to electromagnetic coupling of the conductive member, Equipped with, A device for inspecting load distribution sensors.

2. The conductive member covers the conductive sheet over a predetermined area. An inspection device for a load distribution sensor according to claim 1.

3. The conductive member is a conductive member having an area that is approximately equal to or smaller than the measurement area defined by the first loop electrode and the second loop electrode of the load distribution sensor. An inspection device for a load distribution sensor according to claim 1 or 2.

4. The conductive member is a conductive member having an area smaller than the measurement area defined by the first loop electrode and the second loop electrode of the load distribution sensor. The conductive member is further provided with a moving mechanism for sliding it on the measurement area. An inspection device for a load distribution sensor according to claim 1 or 2.

5. The conductive member is made of the same material as the conductive sheet, and is thicker than the conductive sheet. An inspection device for a load distribution sensor according to claim 1 or 2.

6. The conductive member is made of a material with a lower resistance value than the conductive sheet. An inspection device for a load distribution sensor according to claim 1 or 2.

7. A method for inspecting a load distribution sensor comprising: a plurality of first loop electrodes arranged parallel to each other within a first surface; a plurality of second loop electrodes arranged parallel to each other in a direction perpendicular to the first loop electrodes within a second surface parallel to the first surface; and a conductive sheet provided on the second surface via an intermediate layer that deforms in accordance with pressing force, wherein one of the first loop electrodes and the second loop electrodes is driven and a signal is detected from the other by electromagnetic coupling, the method being used to inspect the load distribution sensor. The steps include: placing a conductive member with a lower resistance value than the conductive sheet on the conductive sheet so as to cover the electromagnetic coupling portion of the first loop electrode and the second loop electrode; The steps include detecting a signal due to electromagnetic coupling of the conductive member, including, Inspection method for load distribution sensors.

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