Inspection device and inspection method for load distribution sensor

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 device and an inspection method for a load distribution sensor. [Background technology]

[0002] Patent Document 1 discloses a pressure distribution detection device that utilizes changes 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 that are respectively arranged on opposing surfaces of a substrate, and a cushioning material and a conductive sheet that are provided in this order on the detection-side loop-shaped wirings. The drive-side loop-shaped wirings and the detection-side loop-shaped wirings are each configured to be electromagnetically coupled. The pressure distribution is detected by detecting changes in the degree of this electromagnetic coupling. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-63526 A Summary of the Invention [Problem to be solved by the invention]

[0004] One of the failure modes of such an electromagnetic induction type load distribution sensor is fatigue failure of the conductive sheet. When inspecting the location of such a failure in the conductive sheet, it is difficult to detect it visually because a protective plate is provided over almost the entire surface of the conductive sheet.

[0005] In addition, since such load sensors generally have a wide detection surface, applying loads to the load distribution sensor from one end to the other and testing based on the change in load value takes a huge amount of time. Furthermore, since the location of failure due to fatigue failure of the conductive sheet is very small, the change in load value is small and it is difficult to find it accurately.

[0006] The present invention has been made in consideration of such problems, and an object of the present invention is to provide an inspection device and an inspection method for a load distribution sensor that can perform inspection easily and accurately even if the damaged area of ​​the conductive sheet is very small. [Means for solving the problem]

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

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

[0009] In the load distribution sensor inspection device according to the third aspect of the present invention, the conductive member has an area 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.

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

[0011] In the 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 the load distribution sensor inspection device according to a sixth aspect of the present invention, the conductive member is made of a material having a lower resistance value than the conductive sheet.

[0013] A seventh aspect of the present invention relates to a method for inspecting a load distribution sensor comprising first loop electrodes arranged in parallel on a first surface, second loop electrodes arranged in parallel on a second surface parallel to the first surface in a direction perpendicular to the first loop electrodes, and a conductive sheet provided on the second surface via an intermediate layer that deforms in response to a pressing force, the method driving one of the first loop electrodes and the second loop electrodes and detecting a signal due to electromagnetic coupling from the other, the method comprising the steps of: arranging a conductive member having a lower resistance value than the conductive sheet on the conductive sheet so as to cover the electromagnetic coupling portion between the first loop electrodes and the second loop electrode; and detecting a signal due to electromagnetic coupling of the conductive member. Effect of the Invention

[0014] According to the present invention, even if the location of destruction in the conductive sheet is very small, it is possible to carry out inspection easily and accurately. [Brief description of the drawings]

[0015] [Figure 1] 1 is a diagram illustrating an inspection device for a load distribution sensor according to an embodiment. [Diagram 2] FIG. 13 is a diagram showing an example in which a load distribution sensor is applied to a treadmill. [Diagram 3] 1 is a diagram illustrating a schematic configuration of a load distribution sensor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In addition, in each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary.

[0017] The embodiment relates to an inspection device for an electromagnetic induction type load distribution sensor. First, a schematic configuration of the load distribution sensor will be described with reference to Fig. 3. Fig. 3 is a diagram for explaining the schematic configuration of the load distribution sensor. Fig. 3 shows a partially exploded view of the layered structure of the load distribution sensor described in Patent Document 1.

[0018] As shown in Fig. 3, the load distribution sensor 10 includes a driving-side loop electrode 11, a detection-side loop electrode 12, an intermediate layer 13, a conductive sheet 14, a driving unit 15, and a detection unit 16. The driving-side loop electrodes 11 are arranged in parallel on a first plane. The detection-side loop electrodes 12 are arranged in parallel on a second plane on the first plane that is parallel to the first plane. The detection-side loop electrodes 12 are each perpendicular to the driving-side loop electrodes 11.

[0019] The driving-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 Fig. 3, the driving-side loop electrode 11 is arranged on the back surface of the substrate, and the detection-side loop electrode 12 is arranged on the front surface of the substrate, but the arrangement may be reversed. In addition, the driving-side loop electrode 11 and the detection-side loop electrode 12 are not limited to being arranged on both surfaces of a single substrate. For example, two substrates on which the driving-side loop electrode 11 and the detection-side loop electrode 12 are formed may be stacked, or the loop electrodes may be arranged by aerial wiring or the like without using a substrate.

[0020] Coil patterns are formed on the driving side loop electrode 11 and the detection side loop electrode 12 in accordance with the intersection positions of the loop electrodes. These coil patterns are configured to be electromagnetically coupled to form an electromagnetic coupling section 17. The electromagnetic coupling sections 17 are arranged in a matrix pattern within the measurement area of ​​the load distribution sensor 10. Note that various conventional configurations can be applied to the configuration of the electromagnetic coupling section.

[0021] A conductive sheet 14 is disposed on the detection-side loop electrode 12. The conductive sheet 14 is a conductive film, and is made of, for example, aluminum foil or copper foil. For example, aluminum foil having a thickness of 0.1 to 0.2 mm can be used as the conductive sheet 14. The conductive sheet 14 is provided over substantially the entire surface of the measurement area 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, to be stepped on directly during load measurement. Such a protective plate may be made of, for example, a waterproof sheet such as tarpaulin. Tarpaulin is a composite sheet in which a fiber cloth is sandwiched between soft synthetic resin films. The protective plate may also be made 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 is disposed between the drive-side loop electrode 11 and the conductive sheet 14. The intermediate layer 13 is a cushioning material that deforms in response to a pressing force. The intermediate layer 13 is made of an insulating material, such as urethane foam, that does not affect electromagnetic coupling.

[0024] A driving unit 15 is connected to the driving-side loop electrode 11, and a detection unit 16 is connected to the detection-side loop electrode 12. The driving unit 15 sequentially drives the multiple driving-side loop electrodes 11 with AC current. The detection unit 16 sequentially detects changes in the degree of electromagnetic coupling of each electromagnetic coupling unit 17. Note that the driving unit 15 and the detection unit 16 can be configured in various conventional ways.

[0025] In such a load distribution sensor 10, when the driving-side loop electrode 11 is driven, an AC electromotive force is induced in the detection-side loop electrode 12 by the electromagnetic coupling of the electromagnetic coupling portion 17. The magnitude of this electromotive force varies depending on the degree of electromagnetic coupling. The degree of electromagnetic coupling varies depending on the distance between the electromagnetic coupling portion 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 portion 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 current from the multiple detection-side loop electrodes 12.

[0027] In this way, in the load distribution sensor 10, the load is measured at the electromagnetic coupling portion 17 between the driving-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 driving-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 broken due to fatigue 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 the embodiment detects the broken part of the conductive sheet 14.

[0029] Fig. 1 is a diagram for explaining an inspection device for a load distribution sensor 10 according to an embodiment. Fig. 1 shows an example in which the size of the measurement area of ​​the load distribution sensor 10 is 590 mm long and 1600 mm wide. As an example, a drive unit 15 and a detection unit 16 are provided together near the center of one of the long sides of the load distribution sensor 10. Note that the size, shape, arrangement, etc. of these are not limited to the example shown in the figure.

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

[0031] The conductive member 21 has a lower resistance value than the conductive sheet 14. For example, when the conductive sheet 14 is formed of an aluminum foil having a thickness of 0.1 to 0.2 mm, the conductive member 21 can be a metal plate of a similar thickness and made of silver, gold, copper, or the like, which has a lower resistance value than aluminum.

[0032] It is also possible to use the same material as the conductive sheet 14 as the material of the conductive member 21 and make the thickness of the conductive member 21 greater than the thickness of the conductive sheet 14, thereby making the resistance value of the conductive member 21 smaller than that of the conductive sheet 14. For example, when the conductive sheet 14 is formed of aluminum foil having a thickness of 0.1 to 0.2 mm, the conductive member 21 can be a metal plate made of aluminum having 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 value than the conductive sheet 14, eddy currents due to electromagnetic induction are more likely to occur in the conductive member 21 than in the conductive sheet 14. Therefore, when the conductive member 21 is arranged so as to cover the conductive sheet 14, the eddy currents generated in the conductive member 21 at the destruction site of the conductive sheet 14 due to the induced magnetic field generated by passing an AC current through the coil pattern of the electromagnetic coupling part 17 are larger than the eddy currents generated in the conductive sheet 14 at the non-destructive site of the conductive sheet 14.

[0034] Due to the difference in the magnitude of this eddy current, the value of the AC electromotive force induced in the detection-side loop electrode 12 at the broken portion of the conductive sheet 14 is greater than that at the non-broken portion. Therefore, at the broken portion of the conductive sheet 14, the detection value detected by the detection unit 16 is greater than that at the non-broken portion of the conductive sheet 14. In other words, the detection unit 16 also functions as a detection unit that detects a signal 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 arranging a conductive member 21 having a lower resistance value than the conductive sheet 14 on the conductive sheet 14 so as to cover the electromagnetic coupling portion 17 between the driving-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 portion 16.

[0036] In this manner, in the embodiment, rather than carrying out an inspection by actually applying a load to the load distribution sensor 10, it is possible to carry out an inspection to identify the location of destruction in the conductive sheet 14 by utilizing the change in the detection value due to electromagnetic induction in the conductive member 21. By arranging the load distribution sensor 10 so as to cover it and observing the change in the detection value output from the detection unit 16, it becomes possible to carry out an inspection simply and accurately even if the location of destruction in the conductive sheet 14 is minute.

[0037] In the embodiment, the conductive member 21, which is 500 mm long and 500 mm wide, is slid vertically and horizontally over the measurement area of ​​the load distribution sensor 10 to inspect the conductive sheet 14 over the entire measurement area. This makes it possible to identify the broken parts of the conductive sheet 14 over almost the entire measurement area of ​​the load distribution sensor 10 in a short time.

[0038] There is no particular limitation on the size of the conductive member 21. For example, it is possible to inspect the entire measurement area at once by using a conductive member 21 having a size substantially equal to the measurement area defined by the driving-side loop electrode 11 and the detection-side loop electrode 12.

[0039] Moreover, the conductive member 21 may have an area smaller than the measurement region. Since the inspection device 20 inspects the broken portion of the conductive sheet 14 using the change in the detection value due to the electromagnetic induction of the conductive member 21, the conductive member 21 may cover the conductive sheet 14 with a predetermined area so as to cover the adjacent electromagnetic coupling parts 17. Moreover, a strip-shaped conductive member 21 having a length equal to the vertical length of the measurement region of the load distribution sensor 10 may be slid in one direction from one end of the load distribution sensor 10 to the other end.

[0040] The shape of the conductive member 21 is not limited to a plate shape. The conductive member 21 may be cylindrical or prismatic as long as it covers a predetermined area on the conductive sheet 14 so that the change in the detection value due to the electromagnetic induction of the conductive member 21 can be measured. In this case, the conductive member 21 can be rotated in the circumferential direction to move on the load distribution sensor 10.

[0041] The inspection device 20 may 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 may be, for example, a mechanism that is moved manually by an operator, a mechanism that applies force elastically using a spring or the like, or a mechanism that is operated by a predetermined actuator.

[0042] The above-described load distribution sensor 10 is applied to a treadmill 101 of a walking training device 100. Fig. 2 is a diagram showing an example in which the load distribution sensor 10 is applied to the treadmill 101. The treadmill 101 is a device that encourages a 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 pulley to move the ring-shaped belt 102. A trainee undergoing walking training rides on the belt 102 and walks in accordance with the movement of the belt 102. The load distribution sensor 10 is disposed 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 with the load distribution sensor 10 incorporated in the walking training device 100 by observing the change in the detection value due to electromagnetic induction of the conductive member 21.

[0045] Moreover, by driving the belt 102, the conductive member 21 arranged on the belt 102 can be moved together 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] The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0047] 10 Load distribution sensor 11 Drive side loop electrode 12 Detection loop electrode 13. Middle Class 14 Conductive sheet 15 Drive unit 16 Detection section 17 Electromagnetic coupling section 20 Inspection Equipment 21 Conductive materials 100 Walking training device 101 Treadmill 102 Belt

Claims

1. An inspection device for a load distribution sensor comprising: first loop electrodes arranged in parallel in a first plane; second loop electrodes arranged in parallel in a direction perpendicular to the first loop electrodes in a second plane parallel to the first plane on the first plane; and a conductive sheet provided on the second plane via an intermediate layer that deforms in response to a pressing force, the device driving one of the first loop electrodes and the second loop electrodes and detecting a signal due to electromagnetic coupling from the other, a conductive member having a resistance value lower than that of the conductive sheet, the conductive member being disposed on the conductive sheet so as to cover an electromagnetic coupling portion between the first loop electrode and the second loop electrode; a detection unit that detects a signal due to electromagnetic coupling of the conductive member; Equipped with Load distribution sensor inspection device.

2. The conductive member covers the conductive sheet over a predetermined area.

2. An inspection device for the load distribution sensor according to claim 1.

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

4. the conductive member has an area smaller than a measurement area defined by the first loop electrode and the second loop electrode of the load distribution sensor, The measuring device further includes a moving mechanism for sliding the conductive member on the measurement area.

3. An inspection device for the 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.

3. An inspection device for the load distribution sensor according to claim 1 or 2.

6. The conductive member is made of a material having a lower resistance than the conductive sheet.

3. An inspection device for the load distribution sensor according to claim 1 or 2.

7. A method for inspecting a load distribution sensor including: first loop electrodes arranged in parallel in a first plane; second loop electrodes arranged in parallel in a direction perpendicular to the first loop electrodes in a second plane parallel to the first plane on the first plane; and a conductive sheet provided on the second plane via an intermediate layer that deforms in response to a pressing force, the method comprising driving one of the first loop electrodes and the second loop electrodes and detecting a signal due to electromagnetic coupling from the other, the method comprising: arranging a conductive member having a resistance value lower than that of the conductive sheet on the conductive sheet so as to cover an electromagnetic coupling portion between the first loop electrode and the second loop electrode; detecting a signal due to electromagnetic coupling of the conductive member; Including, How to inspect a load distribution sensor.

Images