Inspection device and inspection method for load distribution sensor

Abstract

The invention relates to an inspection apparatus and an inspection method for a load distribution sensor. An inspection device according to an embodiment is used for a load distribution sensor including driving-side ring electrodes arranged parallel to each other in a first surface, detection-side ring electrodes arranged parallel to each other in a direction orthogonal to the driving-side ring electrodes in a second surface parallel to the first surface, and a conductive sheet disposed on the second surface through an intermediate layer that deforms according to pressure. And a load distribution sensor that drives one of the drive-side ring electrode and the detection-side ring electrode and detects a signal generated due to electromagnetic coupling from the other, the inspection device including a conductive member that has a lower resistance value than the conductive sheet and is disposed thereon, and a conductive member covering an electromagnetic coupling portion between the drive-side ring electrode and the detection-side ring electrode, and a detection unit detecting a signal generated due to the electromagnetic coupling of the conductive member.

Description

Technical Field

[0001] The invention relates to an inspection device and an inspection method for a load distribution sensor. Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2009-63526 (JP 2009-63526A) discloses a pressure distribution detection device that uses the change in the degree of electromagnetic coupling caused by the pressure applied to the detection surface. The pressure distribution detection device includes a plurality of drive side loops and detection side loops respectively arranged on the opposite surfaces of a substrate, and a buffer material and a conductive sheet sequentially arranged on the detection side loops. The drive side loops and the detection side loops are configured to be electromagnetically coupled together, respectively. Pressure distribution is detected by detecting the change in the degree of this electromagnetic coupling. Summary of the invention

[0003] One of the failure modes of such electromagnetic induction load distribution sensors is fatigue fracture of the conductive sheet. When inspecting the location of such fracture of the conductive sheet, visual inspection is difficult because a protective plate is provided on substantially the entire surface of the conductive sheet.

[0004] Another problem is that since such a load sensor generally has a large detection surface, it takes a lot of time to perform inspection based on changes in load values ​​by sequentially applying loads to the load distribution sensor from one end. In addition, since the position of a fracture in the conductive sheet due to fatigue fracture is minute, changes in load values ​​are small, making it difficult to accurately find the position.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an inspection device and an inspection method for a load distribution sensor, which can perform inspection simply and accurately even when the position of a break in a conductive sheet is minute.

[0006] The inspection device for a load distribution sensor according to the first scheme of the present invention is an inspection device for the following load distribution sensor: the load distribution sensor includes a plurality of first annular electrodes arranged in parallel with each other in a first surface, a plurality of second annular electrodes arranged in parallel with each other in a direction orthogonal to the first annular electrodes in a second surface located above the first surface and parallel to the first surface, and a conductive sheet provided on the second surface through an intermediate layer deformed according to pressure. The load distribution sensor is configured to drive one of the first annular electrode and the second annular electrode and detect a signal generated due to electromagnetic coupling from the other. The inspection device includes a conductive member having a lower resistance value than the conductive sheet and arranged on the conductive sheet so as to cover the electromagnetic coupling portion between the first annular electrode and the second annular electrode, and a detection unit that detects a signal generated due to electromagnetic coupling of the conductive member.

[0007] In the inspection device for a load distribution sensor according to the second aspect of the present invention, the conductive member covers the conductive sheet over a predetermined area.

[0008] In the inspection device for a load distribution sensor according to the third aspect of the present invention, the conductive member is a conductive member having an area substantially equal to or smaller than a measurement field of the load distribution sensor defined by the first annular electrode and the second annular electrode.

[0009] In the inspection device for a load distribution sensor according to a fourth aspect of the present invention, the conductive member is a conductive member having an area smaller than a measurement area of ​​the load distribution sensor defined by the first annular electrode and the second annular electrode. The inspection device further includes a moving mechanism for sliding the conductive member over the measurement area.

[0010] In the inspection device for a load distribution sensor 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.

[0011] In the inspection device for a load distribution sensor 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.

[0012] The inspection method for a load distribution sensor according to the seventh scheme of the present invention is an inspection method for the following load distribution sensor: the load distribution sensor includes a plurality of first annular electrodes arranged in parallel with each other in a first surface, a plurality of second annular electrodes arranged in parallel with each other in a direction orthogonal to the first annular electrodes in a second surface located above the first surface and parallel to the first surface, and a conductive sheet provided on the second surface through an intermediate layer deformed according to pressure. The load distribution sensor is configured to drive one of the first annular electrode and the second annular electrode, and detect a signal generated due to electromagnetic coupling from the other. The inspection method includes 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 annular electrode and the second annular electrode, and detecting a signal generated due to electromagnetic coupling of the conductive member.

[0013] The present invention makes it possible to perform inspection simply and accurately even if the position of a break in a conductive sheet is minute. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, wherein like reference numerals represent like elements, and wherein:

[0015] Figure 1 is a view showing an inspection device for a load distribution sensor according to an embodiment;

[0016] Figure 2 is a view showing an example in which a load distribution sensor is applied to a treadmill; and

[0017] Figure 3 is a view showing a schematic configuration of a load distribution sensor. DETAILED DESCRIPTION

[0018] The embodiments of the present invention will be described below with reference to the accompanying drawings. In order to clarify the description, the following text and drawings are appropriately abbreviated and simplified. The same elements in the drawings are represented by the same reference numerals, and their repeated description is omitted when necessary.

[0019] The embodiment relates to an inspection device for an electromagnetic induction load distribution sensor. Figure 3 A schematic configuration of a load distribution sensor is described. Figure 3 is a view showing a schematic configuration of a load distribution sensor. Figure 3 , the stacked structure of the load distribution sensor described in JP2009-63526A is shown partially exploded.

[0020] like Figure 3As shown, the load distribution sensor 10 includes a driving side annular electrode 11, a detection side annular electrode 12, an intermediate layer 13, a conductive sheet 14, a driving unit 15 and a detection unit 16. A plurality of driving side annular electrodes 11 are arranged in parallel with each other in a first surface. A plurality of detection side annular electrodes 12 are arranged in parallel with each other in a second surface located above the first surface and parallel to the first surface. The detection side annular electrode 12 is orthogonal to each of the driving side annular electrodes 11.

[0021] The driving side annular electrode 11 and the detecting side annular electrode 12 are arranged on opposite surfaces of, for example, a substrate (not shown). Figure 3 In the example shown, the drive side annular electrode 11 is arranged on the rear surface of the substrate, and the detection side annular electrode 12 is arranged on the front surface of the substrate, but these annular electrodes may be arranged in the opposite manner. In addition, the drive side annular electrode 11 and the detection side annular electrode 12 are not limited to the example of being arranged on both surfaces of one substrate, respectively. For example, two substrates in which the drive side annular electrode 11 and the detection side annular electrode 12 are respectively formed may be stacked, or these annular electrodes may be arranged by aerial wiring or the like without using a substrate.

[0022] In each of the driving side annular electrode 11 and the detecting side annular electrode 12, a coil-like pattern is formed to align with the intersection position between these annular electrodes. These coil-like patterns are configured to be electromagnetically coupled together and form an electromagnetic coupling portion 17. The electromagnetic coupling portion 17 is arranged in a matrix form within the measurement area of ​​the load distribution sensor 10. For the configuration of the electromagnetic coupling portion, various conventional configurations can be adopted.

[0023] The conductive sheet 14 is arranged on the detection side annular electrode 12. The conductive sheet 14 is a thin film having conductivity and is formed of, for example, aluminum foil, copper foil, etc. As the conductive sheet 14, for example, an aluminum foil having a thickness of 0.1 to 0.2 mm can be used. The conductive sheet 14 is provided on substantially the entire surface of the measurement area of ​​the load distribution sensor 10.

[0024] Although not shown here, a protective plate for the purpose of directly stepping on it during load measurement is provided on substantially the entire surface of the conductive sheet 14. As a material of such a protective plate, for example, a waterproof sheet such as a tarpaulin can be used. A tarpaulin is a composite sheet in which a fiber cloth is sandwiched between soft synthetic resin films. Alternatively, the protective plate may be formed of an acrylic plate, a polycarbonate plate, or the like.

[0025] The intermediate layer 13 is arranged between the detection side annular electrode 12 and the conductive sheet 14. In the case where the drive side annular electrode 11 is provided on the front surface of the substrate, the intermediate layer 13 is arranged between the drive side annular electrode 11 and the conductive sheet 14. The intermediate layer 13 is a buffer material that deforms according to pressure. As the intermediate layer 13, an insulating material that does not affect electromagnetic coupling, such as polyurethane foam, is used.

[0026] The driving unit 15 is connected to the driving side annular electrode 11, and the detecting unit 16 is connected to the detecting side annular electrode 12. The driving unit 15 sequentially drives the plurality of driving side annular electrodes 11 by an alternating current. The detecting unit 16 sequentially detects a change in the degree of electromagnetic coupling at the electromagnetic coupling portion 17. For the driving unit 15 and the detecting unit 16, various conventional configurations may be employed.

[0027] In this load distribution sensor 10, when the driving side annular electrode 11 is driven, an alternating electromotive force is induced in the detection side annular electrode 12 by electromagnetic coupling at the electromagnetic coupling portion 17. The magnitude of the 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.

[0028] 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 annular electrode 12 changes. The load distribution sensor 10 detects the load value and its position by sequentially detecting the current from the plurality of detection-side annular electrodes 12.

[0029] In this way, in the load distribution sensor 10, measurement of the load is performed at the electromagnetic coupling portion 17 between the driving side annular electrode 11 and the detecting side annular electrode 12. Therefore, the measurement area of ​​the load distribution sensor 10 is defined by the driving side annular electrode 11 and the detecting side annular electrode 12.

[0030] In such a load distribution sensor 10 , if the conductive sheet 14 breaks due to fatigue fracture or the like, a value different from the value that should be detected under normal conditions is output. The inspection device for the load distribution sensor 10 according to the present embodiment detects the break position in the conductive sheet 14 .

[0031] Figure 1 1 is a view showing an inspection device for the load distribution sensor 10 according to the present embodiment. Figure 1 , an example is shown in which the size of the measurement area of ​​the load distribution sensor 10 is 590 mm wide and 1600 mm long. As an example, the drive unit 15 and the detection unit 16 are jointly arranged near the center of one long side of the load distribution sensor 10. These sizes, shapes, arrangement positions, etc. are not limited to the examples shown in the drawings.

[0032] The conductive member 21 is arranged on the load distribution sensor 10. The conductive member 21 is arranged on the conductive sheet 14 over a predetermined area so as to cover the electromagnetic coupling portion 17 between the driving side annular electrode 11 and the detecting side annular electrode 12. Figure 1 In the example shown, the conductive member 21 having a size of 500 mm in width and 500 mm in length is used.

[0033] The conductive member 21 has a resistance value lower than that of the conductive sheet 14. For example, in the case where the conductive sheet 14 is formed of an aluminum foil having a thickness of 0.1 to 0.2 mm, a metal plate made of silver, gold, copper, or the like having the same thickness as aluminum and a lower resistance value than aluminum can be used as the conductive member 21.

[0034] By making the thickness of the conductive member 21 thicker than the thickness of the conductive sheet 14 while using the same material as the conductive sheet 14 as the material of the conductive member 21, it is also possible to make the resistance value of the conductive member 21 lower than the resistance value of the conductive sheet 14. For example, in the case where the conductive sheet 14 is formed of an aluminum foil having a thickness of 0.1 to 0.2 mm, a metal plate made of aluminum that is approximately 1 to 5 mm thick and thicker than the conductive sheet 14 can be used as the conductive member 21.

[0035] The conductive member 21 has a lower resistance value than the conductive sheet 14, and thus is more likely to generate eddy current due to electromagnetic induction than the conductive sheet 14. Therefore, when the conductive member 21 is arranged to cover the conductive sheet 14, the eddy current generated in the conductive member 21 at the broken position of the conductive sheet 14 due to the induction field generated by passing an alternating current through the coil-shaped pattern at the electromagnetic coupling portion 17 becomes higher than the eddy current generated in the conductive sheet 14 at the position where the conductive sheet 14 is not broken.

[0036] Due to the difference in the magnitude of the eddy current, the value of the alternating electromotive force induced in the detection-side annular electrode 12 at the position of the break in the conductive sheet 14 becomes greater than that at the position where the break is not made. Therefore, at the position of the break in the conductive sheet 14, the detection value detected by the detection unit 16 becomes greater than that at the position where the conductive sheet 14 is not broken. Therefore, the detection unit 16 also functions as a detection unit that detects a signal generated due to the electromagnetic coupling of the conductive member 21 in the inspection device 20.

[0037] Here, an inspection method for the load distribution sensor 10 according to the embodiment will be described. The 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 drive side annular electrode 11 and the detection side annular electrode 12, and detecting a signal generated due to the electromagnetic coupling of the conductive member 21 by the detection unit 16.

[0038] Therefore, in this embodiment, instead of performing the inspection by actually applying a load to the load distribution sensor 10, the inspection for determining the position of the break in the conductive sheet 14 can be performed by using the change in the detection value due to the electromagnetic induction of the conductive member 21. By arranging the conductive member 21 to cover the load distribution sensor 10 and observing the change in the detection value output from the detection unit 16, the inspection can be performed simply and accurately even when the position of the break in the conductive sheet 14 is minute.

[0039] In the embodiment, by sliding the conductive member 21 having a size of 500 mm wide and 500 mm long vertically and horizontally over the measurement area, the inspection of the conductive sheet 14 is performed over the entire surface of the measurement area of ​​the load distribution sensor 10. Therefore, the fracture position in the conductive sheet 14 in substantially the entire surface of the measurement area of ​​the load distribution sensor 10 can be determined in a short time.

[0040] The size of the conductive member 21 is not particularly limited. For example, a conductive member 21 having a size substantially equal to the measurement area defined by the drive-side annular electrode 11 and the detection-side annular electrode 12 may be used to inspect the entire surface of the measurement area at once.

[0041] Or the conductive member 21 may have an area smaller than the measurement area. In the inspection device 20, since the break position of the conductive sheet 14 is inspected using a change in the detection value due to the electromagnetic induction of the conductive member 21, the conductive member 21 should cover the conductive sheet 14 at least over a predetermined area so as to cover a plurality of adjacent electromagnetic coupling portions 17. In addition, the belt-shaped conductive member 21 having a length equal to the length of the width of the measurement area of ​​the load distribution sensor 10 may be slidable in one direction from one end toward the other end of the load distribution sensor 10.

[0042] The shape of the conductive member 21 is not limited to the plate shape. The shape of the conductive member 21 may be cylindrical, prismatic, etc., as long as the conductive member 21 covers the conductive sheet 14 over a predetermined area to allow measurement of changes in the detection value due to electromagnetic induction of the conductive member 21. In this case, the conductive member 21 may be moved on the load distribution sensor 10 by rotating in the circumferential direction.

[0043] 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; for example, the moving mechanism may be manually moved by an operator's operation, or may elastically apply a force using a spring or the like, or may be actuated by a predetermined actuator.

[0044] The load distribution sensor 10 is applied to a treadmill 101 of a gait training device 100 . Figure 2 1 is a diagram showing an example in which the load distribution sensor 10 is applied to a treadmill 101. The treadmill 101 is a device that prompts an exerciser to walk.

[0045] The treadmill 101 includes a pulley and a motor (not shown) in addition to the endless belt 102. When the pulley is rotated by the motor, the endless belt 102 rotates. A trainee who receives gait training rides on the belt 102 and performs walking motion according to the movement of the belt 102. The load distribution sensor 10 is arranged below the belt 102. The load distribution sensor 10 detects the distribution of the load received from the feet of the trainee.

[0046] When the inspection of the conductive sheet 14 of such a load distribution sensor 10 is performed, the conductive member 21 may be arranged on the belt 102 so as to cover the conductive sheet 14. Therefore, the inspection of the conductive sheet 14 can also be performed by observing the change in the detection value due to the electromagnetic induction of the conductive member 21 in a state where the load distribution sensor 10 is incorporated into the gait training device 100.

[0047] By driving the belt 102, the conductive member 21 disposed on the belt 102 can be moved on the load distribution sensor 10 together with the belt 102. In this case, there is no need to separately provide a moving mechanism for sliding the conductive member 21.

[0048] The present invention is not limited to the above-described embodiments, and can be appropriately modified within a scope not departing from the gist of the present invention.

Claims

1. An inspection device for a load distribution sensor, the load distribution sensor comprising a plurality of first annular electrodes arranged in parallel with each other in a first surface, a plurality of second annular electrodes arranged in parallel with each other in a direction orthogonal to the first annular electrodes in a second surface located above and parallel to the first surface, and a conductive sheet provided on the second surface via an intermediate layer deformed according to pressure, the load distribution sensor being configured to drive one of the first annular electrode and the second annular electrode and to detect a signal generated due to electromagnetic coupling from the other, the inspection device comprising: a conductive member having a lower resistance value than the conductive sheet and arranged on the conductive sheet so as to cover the electromagnetic coupling portion between the first annular electrode and the second annular electrode; as well as A detection unit detects a signal generated due to electromagnetic coupling of the conductive member.

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

3. The inspection device for a load distribution sensor according to claim 1 or 2, wherein: The conductive member is a conductive member having an area substantially equal to or smaller than a measurement region of the load distribution sensor defined by the first annular electrode and the second annular electrode.

4. The inspection device for a load distribution sensor according to claim 1 or 2, wherein: The conductive member is a conductive member having an area smaller than a measurement region of the load distribution sensor defined by the first annular electrode and the second annular electrode; and The inspection device further includes a moving mechanism that slides the conductive member over the measurement area.

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

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

7. An inspection method for a load distribution sensor, the load distribution sensor comprising a plurality of first annular electrodes arranged in parallel with each other in a first surface, a plurality of second annular electrodes arranged in parallel with each other in a direction orthogonal to the first annular electrodes in a second surface located above and parallel to the first surface, and a conductive sheet provided on the second surface via an intermediate layer deformed according to pressure, the load distribution sensor being configured to drive one of the first annular electrode and the second annular electrode and to detect a signal generated by electromagnetic coupling from the other, the inspection method comprising the following steps: disposing a conductive member having a lower resistance value than the conductive sheet on the conductive sheet so as to cover an electromagnetic coupling portion between the first annular electrode and the second annular electrode; as well as A signal generated due to electromagnetic coupling of the conductive member is detected.

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