WO2016158425A1

WO2016158425A1 - Load measuring apparatus

Info

Publication number: WO2016158425A1
Application number: PCT/JP2016/058365
Authority: WO
Inventors: 田中　守; 勇三今堀; 山口　和也; 計之藤本; 正光小谷
Original assignee: 株式会社イマック
Priority date: 2015-03-30
Filing date: 2016-03-16
Publication date: 2016-10-06
Also published as: JP6522740B2; JPWO2016158425A1

Abstract

Provided is a load measuring apparatus capable of measuring a partial load acting on each portion of the sole of a foot, and capable of highly accurate and stable measurements with respect to environmental changes such as noise and temperature. This load measuring apparatus 1 comprises: a load sensor unit 2 obtained by forming a plurality of capacitors Ca₁-Cd₁, Ca₂-Cd₂ wherein a first sheet-shaped elastic body 21 cyclically provided with a plurality of cavities and a flat second sheet-shaped elastic body 22 serve as dielectric bodies, and a first sheet-shaped conductive elastic body 23, a plurality of second sheet-shaped conductive elastic bodies 24a-24d, and a third sheet-shaped conductive elastic body 25 serve as electrodes; and an electric circuit 3 that has first and second AC output circuits 31, 32 that apply an AC voltage to terminals 23t, 25t of the first and third sheet-shaped conductive elastic bodies 23, 25, and current measurement circuits 33a-33d that measure the AC currents flowing to terminals 24at-24dt of the plurality of the second sheet-shaped conductive elastic bodies 24a-24d, and converts the AC currents into load measurement voltages.

Description

Load measuring device

The present invention relates to a load measuring device including a load sensor portion provided on the inner bottom of footwear.

Conventionally, a load measuring device including a load sensor unit provided on the inner bottom of footwear is known. This load measuring device can measure the load applied to the lower limbs during free walking. Therefore, it is useful for rehabilitation of the lower limbs and the like that gradually increase the load applied to the lower limbs. Some of these load measuring devices electrically detect a change in capacitance due to a load in the load sensor unit.

For example, in Patent Document 1, the capacitance is changed corresponding to partial loads formed on shoe soles and applied to each part of the sole (the rear foot part, the left front foot part, and the right front foot part). A walking factor analyzer (load measuring device) having a plurality of variable capacitance pressure sensors (load sensor units) is disclosed. The change in capacitance of the variable capacitor of the variable capacitance pressure sensor is taken out as a change in pulse oscillation frequency. This walking factor analyzer can measure the partial load of each part and analyze the walking state more strictly.

Patent Document 2 discloses a load measuring unit (load sensor unit) that is formed in conformity with the contour shape of the back surface of the wearer's foot and detects capacitance at a plurality of locations on the back surface of the foot that changes due to weight shift. A center-of-gravity position detection device (load measurement device) is disclosed. Time until one of the upper electrode and the lower electrode forming the capacitance is connected to GND and the other is connected to a constant voltage power source, and the voltage value between the upper electrode and the lower electrode reaches a predetermined value To calculate the capacitance. The center-of-gravity position detection device can detect the movement of the center-of-gravity position.

In Patent Document 3, a sheet-like elastic body in which a large number of voids or depressions are periodically provided and a flat sheet-like elastic body made of the same material are used as dielectrics, and these dielectrics are sandwiched. A load measuring device having a load sensor portion formed by forming two capacitors using three sheet-like conductive elastic bodies as electrodes is disclosed. This load measuring device detects the total amount of load that is distributed across the load sensor section, and differentially detects the change in capacitance due to the load of the two capacitors. Therefore, it is possible to measure with higher accuracy than those described in

Patent Documents

1 and 2.

Japanese Patent Laid-Open No. 02-55045 International Publication WO2009 / 084387 JP 2008-107231 A

However, even in the load measuring device described in Patent Document 3, the load on each part of the sole is measured as in

Patent Documents

1 and 2, and the strict walking state such as the center-of-gravity sway test is performed. In some cases, analysis of the above is desired.

The present invention has been made in view of the above reasons, and its purpose is to measure the partial load applied to each part of the sole, and to measure stably and highly accurately with respect to environmental changes such as noise and temperature. It is in providing the load measuring device which can do.

In order to achieve the above object, a load measuring device according to an embodiment of the present invention includes a first sheet-like elastic body provided with a large number of gaps or depressions and a flat second sheet made of the same material. A plurality of first sheet-like elastic bodies sandwiched between the first sheet-like conductive elastic body and the first sheet-like conductive elastic body. Two sheet-like conductive elastic bodies, and a second sheet-like conductive elastic body sandwiching the second sheet-like elastic bodies between the plurality of second sheet-like conductive elastic bodies. A plurality of capacitors formed as electrodes, a load sensor provided on the inner bottom of the footwear, a first AC output circuit for applying an AC voltage to a terminal of the first sheet-like conductive elastic body, Second voltage is applied to the terminal of the third sheet-like conductive elastic body. An electric circuit unit including a current output circuit and a current measurement circuit that measures each alternating current flowing through the terminals of the plurality of second sheet-like conductive elastic bodies and converts each alternating current into a load measurement voltage. .

Preferably, the plurality of second sheet-like conductive elastic bodies have a shape in which a single sheet-like conductive elastic body is divided into a plurality of portions by thin grooves.

Preferably, the plurality of second sheet-like conductive elastic bodies are four of a thumb side front part, a little finger side front part, a thumb side rear part, and a little finger side rear part.

According to the load measuring apparatus of the present invention, it is possible to measure the partial load applied to each part of the sole, and it is possible to measure stably and accurately with respect to environmental changes such as noise and temperature.

It is a block circuit diagram showing a load measuring device concerning an embodiment of the present invention. It is a schematic diagram which shows the usage example of a load measuring device same as the above, (a) is footwear, (b) is a load display apparatus. It is a schematic diagram of the load sensor part of a load measuring device same as the above. It is a top view which isolate | separates and shows the component of the load sensor part of a load measuring device same as the above. The detailed structure of the load sensor part of a load measuring device same as the above is shown typically, (a) is an expanded sectional view, (b) is an enlarged plan view of a 1st sheet-like elastic body.

Hereinafter, modes for carrying out the present invention will be described. As shown in FIG. 1, the load measuring device 1 according to the embodiment of the present invention includes a load sensor unit 2 and an electric circuit unit 3.

The load sensor unit 2 is provided on the inner bottom 4a of the footwear 4 as shown in FIG. As shown in FIG. 3, the load sensor unit 2 includes a first sheet-like elastic body 21 and a second sheet-like elastic body 22 as dielectrics, and a first sheet-like conductive elastic body 23 and a plurality of ( As shown in FIG. 1, a plurality of capacitors (a plurality of capacitors, for example, four) are used with the second sheet-like conductive

elastic bodies

24a, 24b, 24c, 24d and the third sheet-like conductive elastic bodies 25 as electrodes. First capacitors Ca ₁ , Cb ₁ , Cc ₁ , Cd ₁ and a plurality of second capacitors Ca ₂ , Cb ₂ , Cc ₂ , Cd ₂ ) are formed.

That is, for example, in the case of four second sheet-like conductive elastic bodies 24a to 24d, the first sheet-like elastic elastic body 23 and the second sheet-like conductive elastic body 24a are used as the first sheet-like elastic elastic body 24a. The part sandwiching the body 21 forms the first capacitor Ca ₁ , and the second sheet-like elastic body 24 a and the third sheet-like conductive elastic body 25 constitute the second sheet-like elastic body. A portion where 22 is sandwiched forms a _second capacitor Ca ₂ , and the first capacitor Ca ₁ and the second capacitor Ca ₂ become the partial load sensor 2 a. A portion in which the first sheet-like elastic body 21 is sandwiched between the first sheet-like conductive elastic body 23 and the second sheet-like conductive elastic body 24b forms a _first capacitor Cb1, 2 of the sheet-like conductive elastic body 24b and the third sheet-like conductive elastic member 25 and the second sheet-like elastic member 22 a portion sandwiched sandwich form a second capacitor Cb _2, first The capacitor Cb ₁ and the second capacitor Cb ₂ serve as the partial load sensor 2b. A portion in which the first sheet-like elastic body 21 is sandwiched between the first sheet-like conductive elastic body 23 and the second sheet-like conductive elastic body 24c forms a _first capacitor Cc1, A portion in which the second sheet-like elastic body 22 is sandwiched between the second sheet-like conductive elastic body 24c and the third sheet-like conductive elastic body 25 forms a _second capacitor Cc2. comprising capacitors Cc ₁ and the second capacitor Cc ₂ and partial load sensor 2c. The first sheet-like conductive elastic body 23 and the first sheet-like elastic member 21 a portion sandwiched sandwiched between the second sheet-like conductive elastic body 24d is formed a first capacitor Cd _1, the 2 of the sheet-like conductive elastic body 24d and a third sheet-like conductive elastic member 25 and the second sheet-like elastic member 22 a portion sandwiched sandwich form a second capacitor Cd _2, first comprising capacitors Cd ₁ between the second capacitor Cd ₂ and partial load sensor 2d. Each of the partial load sensors 2a to 2d detects the load (partial load) over the entire area defined by each of the second sheet-like conductive elastic bodies 24a to 24d.

The first sheet-like conductive elastic body 23 has a terminal 23t, the plurality of second sheet-like conductive elastic bodies 24a to 24d have terminals 24at, 24bt, 24ct, 24dt, and a third sheet-like conductive elastic body 25. Are provided with terminals 25t, respectively (see FIG. 1), connected to an electric circuit unit 3 to be described in detail later through wiring, and from the electric circuit unit 3 to the load sensor unit 2 or from the load sensor unit 2 to the electric circuit unit 3 An electrical signal (voltage or current) is sent to.

Thus, since the first sheet-like conductive elastic body 23 and the third sheet-like conductive elastic body 25 are commonly used by the partial load sensors 2a to 2d, the load sensor unit 2 and the electric circuit unit 3 are used. The number of wirings between is (number of partial load sensors 2a to 2d) +2. Further, as will be described later, in the electric circuit unit 3, there are two AC output circuits for applying an AC voltage to the load sensor unit 2, a first AC output circuit 31 and a second AC output circuit 32. This means that the first sheet-like conductive elastic body 23 and the third sheet-like conductive elastic body 25 are not used in common in the partial load sensors 2a to 2d, and a plurality of first sheet-like conductive elastic bodies are used. When the plurality of third sheet-like conductive elastic bodies are used, the number of wirings is (the number of partial load sensors 2a to 2d) × 3, and the number of AC output circuits of the electric circuit unit 3 is Since (the number of partial load sensors 2a to 2d) × 2, when the first sheet-like conductive elastic body 23 and the third sheet-like conductive elastic body 25 are used in common by the partial load sensors 2a to 2d. This shows that the number of wirings and AC output circuits can be greatly reduced.

First sheet-like elastic body 21, second sheet-like elastic body 22, first sheet-like conductive elastic body 23, an assembly of a plurality of second sheet-like conductive elastic bodies 24a to 24d, and a third sheet As shown in FIGS. 4A to 4E, the conductive elastic body 25 is substantially the same as the shape of the inner bottom 4a of the footwear 4.

Further, as shown in FIG. 5, the first sheet-like elastic body 21 is provided with a large number of gaps or depressions 21s periodically, and the second sheet-like elastic body 22 is provided with the first sheet-like elasticity. The body 21 is made of the same material (that is, a large number of voids or depressions are not provided periodically). Since the first sheet-like elastic body 21 is periodically provided with a large number of voids or depressions 21s, when a load is applied, the volume commensurate with the decrease in thickness expands in this portion, so that the load is almost equal to the load. The thickness changes proportionally. On the other hand, the second sheet-like elastic body 22 is so small that a change in thickness with respect to a load can be ignored.

Therefore, the capacitance values of the plurality of _first capacitors Ca ₁ to Cd ₁ and the plurality of second capacitors Ca ₂ to Cd ₂ can be expressed by the following equations, respectively.
Ca ₁ = ε ₁ · (Sa / da ₁ ) Ca ₂ = ε ₂ · (Sa / d ₂ )
Cb ₁ = ε ₁ · (Sb / db ₁ ) Cb ₂ = ε ₂ · (Sb / d ₂ )
Cc ₁ = ε ₁ · (Sc / dc ₁ ) Cc ₂ = ε ₂ · (Sc / d ₂ )
Cd ₁ = ε ₁ · (Sd / dd ₁ ) Cd ₂ = ε ₂ · (Sd / d ₂ )
Here, the dielectric constants of the first sheet-like elastic body 21 and the second sheet-like elastic body 22 are respectively represented by ε ₁ and ε ₂ , and the areas of the plurality of second sheet-like conductive elastic bodies 24a to 24d are respectively represented. Sa ₁ , db ₁ , dc ₁ are the thicknesses (average thicknesses) of the first sheet-like elastic bodies 21 of the plurality of second sheet-like conductive elastic bodies 24a to 24d, respectively. , Dd ₁ . The thickness of the second sheet-like elastic body 22, as unchanged by the load, as all the thickness of the first sheet-like elastic member 22 at a plurality of second sheet-like conductive elastic body 24a ~ 24d d ₂ Yes.

As shown in FIG. 4 (c), the plurality of second sheet-like conductive elastic bodies 24a to 24d includes a single sheet-like conductive elastic body that is divided into a plurality (four in the figure) by thin groove portions 24g. The shape is preferably divided. That is, it is preferable that the gaps between the plurality of second sheet-like conductive elastic bodies 24a to 24d are narrow. For example, when the plurality of second sheet-like conductive elastic bodies 24a to 24d are four on the thumb side front part, the little finger side front part, the thumb side rear part, and the little finger side rear part, since the groove part 24g is thin, the entire sole Can be calculated by adding all the loads measured by the four parts of the thumb side front part, the little finger side front part, the thumb side rear part, and the little finger side rear part. The load applied to the front of the sole can be calculated by adding the respective loads measured at the front of the thumb and the front of the little finger, and the load applied to the rear of the bottom of the foot It is possible to calculate by adding the respective loads measured at the rear part.

The first sheet-like elastic body 21 and the second sheet-like elastic body 22 include a first sheet-like conductive elastic body 23 such as insulating silicon rubber, and a plurality of second sheet-like conductive elastic bodies 24a. 24d, the third sheet-like conductive elastic body 25 can be made of conductive silicon rubber or the like. Also, a plurality of sheet-like elastic bodies 23 between the first sheet-like elastic elastic body 23 and the first sheet-like elastic body 21 and between the first sheet-like elastic body 21 and the plurality of second sheet-like conductive elastic bodies 24a to 24d. Between the second sheet-like conductive elastic bodies 24a to 24d and the second sheet-like elastic body 22, and between the second sheet-like elastic body 22 and the third sheet-like conductive elastic body 25, for example, is thin. It is possible to bond using an adhesive or the like.

As shown in FIG. 1, the electric circuit unit 3 applies an AC voltage V ₁ to the terminal 23 t of the first sheet-like conductive elastic body 23 and applies an AC current Ia to the plurality of first capacitors Ca ₁ to Cd _1. ₁ , Ib ₁ , Ic ₁ , Id ₁ , and a plurality of second capacitors Ca by applying an AC voltage V ₂ to the terminal 25 t of the third sheet-like conductive elastic body 25. ₂ to Cd ₂ , a second AC output circuit 32 for flowing AC currents Ia ₂ , Ib ₂ , Ic ₂ , and Id _2, and AC currents flowing to terminals 24 at to 24 dt of the second sheet-like conductive elastic bodies 24 a to 24 d And a plurality of

current measurement circuits

33a, 33b, 33c, and 33d that measure Ia ₃ , Ib ₃ , Ic ₃ , and Id ₃ and convert them into voltages (load measurement voltages Va, Vb, Vc, and Vd). The load measurement voltages Va to Vd are voltages corresponding to the load distribution (partial load). In the present embodiment, the AC voltage V ₁ applied to the terminal 23 t of the first sheet-like conductive elastic body 23 and the AC voltage V ₂ applied to the terminal 25 t of the third sheet-like conductive elastic body 25 are: The ground potential is set as a reference potential, and the terminals 24at to 24dt of the plurality of second sheet-like conductive elastic bodies 24a to 24d are set to be held at the same potential as the ground potential.

The first AC output circuit 31 and the second AC output circuit 32 have a phase difference of 180 degrees between the AC currents Ia ₁ to Id ₁ and the AC currents Ia ₂ to Id ₂ when no load is applied to the load sensor unit 2. If the AC voltage V ₁ and the AC voltage V ₂ are adjusted (offset zero adjustment) so that the amplitudes are equal, the AC currents Ia ₁ to Id ₁ flowing through the plurality of first capacitors Ca ₁ to Cd ₁ Since the alternating currents Ia ₂ to Id ₂ flow through the second Ca 2 to Cd 2, the alternating currents Ia ₃ to Id are supplied to the terminals 24 at to 24 dt of the second sheet-like conductive elastic body 24, that is, the plurality of current measuring circuits 33 a to 33 d. ₃ does not flow.

The offset zero adjustment can be performed as follows. When no load is applied to the load sensor unit 2, Ca ₁ = ε ₁ · (Sa / d ₁ ), Cb ₁ = ε ₁ · (Sb / d ₁ ), Cc ₁ = ε ₁ · (Sc / d ₁₎ ), Cd ₁ = ε ₁ · (Sd / d ₁ ). Here, the thickness of the first sheet-shaped elastic body 21 as d _1. Accordingly, Ca ₁ / Ca ₂ = Cb ₁ / Cb ₂ = Cc ₁ / Cc ₂ = Cd ₁ / Cd ₂ = (ε ₁ · d ₂ ) / (ε ₂ · d ₁ ), and a plurality of second sheet shapes The capacitance ratio of the capacitor of the first sheet-like elastic body 21 and the capacitor of the second sheet-like elastic body 22 in the conductive elastic bodies 24a to 24d is all constant.

Here, if the voltage ratio between the alternating voltage V ₂ and the alternating voltage V ₁ is set to V ₂ / V ₁ = (ε ₁ · d ₂ ) / (ε ₂ · d ₁ ), the alternating current ratio Ia ₁ / Ia ₂ , Ib ₁ / Ib ₂ , Ic ₁ / Ic ₂ , Id ₁ / Id ₂ are V ₁ · Ca ₁ / V ₂ · Ca ₂ , V ₁ · Cb ₁ / V ₂ · Cb ₂ , V ₁ · Cc, respectively. _{Since 1} / V ₂ · Cc ₂ and V ₁ · Cd ₁ / V ₂ · Cd ₂ , they are all 1. Therefore, the alternating currents Ia ₁ to Id ₁ flowing through the plurality of first capacitors Ca ₁ to Cd ₁ flow as the alternating currents Ia ₂ to Id ₂ through the plurality of second capacitors Ca ₂ to Cd ₂ , and the second sheet AC currents Ia ₃ to Id ₃ do not flow through the terminals 24at to 24dt of the conductive elastic bodies 24a to 24d, that is, the current measuring circuits 33a to 33d. Thus, the voltage ratio of the alternating voltage V ₂ to the AC voltages V ₁ In the manner described above, all of the respective partial load sensors 2a ~ 2d, at the same time, it is possible to offset nulling. This is because the plurality of partial load sensors 2a to 2d commonly use the first sheet-like elastic body 21 and the second sheet-like elastic body 22 as dielectrics, and the first sheet-like conductive elastic body 23 and the second sheet-like elastic body 23 This is because the three sheet-like conductive elastic bodies 25 are commonly used as electrodes. Note that the AC voltage V ₁ (or AC voltage V ₂ ) can have a frequency of about 10 KHz and an amplitude of about 5 V, for example.

When a load is applied to the load sensor unit 2, the capacitance values of the plurality of first capacitors Ca ₁ to Cd ₁ are increased in accordance with the load distribution, and the alternating currents Ia ₁ to Id ₁ flowing through the first capacitors are increased. On the other hand, since the capacitance values of the plurality of second capacitors Ca ₂ to Cd ₂ hardly change, the alternating currents Ia ₂ to Id ₂ flowing through the second capacitors Ca ₂ to Cd ₂ hardly change. Therefore, the difference between the alternating currents Ia ₁ to Id ₁ and the alternating currents Ia ₂ to Id ₂ flows as the alternating currents Ia ₃ to Id _{3 in} the terminals 24at to 24dt of the second sheet-like conductive elastic bodies 24a to 24d. Then, in the electric circuit unit 3, the alternating currents Ia ₃ to Id ₃ are converted into load measurement voltages Va to Vd.

Thus, load measurement is performed by the difference between the alternating currents Ia ₁ to Id ₁ flowing through the plurality of first capacitors Ca ₁ to Cd ₁ and the alternating currents Ia ₂ to Id ₂ flowing through the plurality of second capacitors Ca ₂ to Cd _2. Since the voltages Va to Vd are obtained, the measurement is stable with respect to environmental changes such as noise and temperature, and highly accurate measurement is possible.

The electric circuit portion 3 can be disposed below the load sensor portion 2 on the inner bottom 4a of the footwear 4. In this case, the terminal 23t of the first sheet-like conductive elastic body 23 in the load sensor unit 2 and the terminals 24at to 24dt of the plurality of second sheet-like conductive elastic bodies 24a to 24d pass through a short vertical wiring. , Connected to the electric circuit section 3. Short wiring contributes to stable and accurate measurement with respect to environmental changes such as noise and temperature. Moreover, the electric circuit part 3 can be made substantially the same as the shape of the inner bottom 4 a of the footwear 4, like the first sheet-like elastic body 21 of the load sensor part 2. The electric circuit unit 3 can also be arranged at other locations of the footwear 4 by using a slightly longer cable for wiring connection with the load sensor unit 2.

The electric circuit unit 3 can also convert the obtained load measurement voltages Va to Vd into digital data load measurement values and send them wirelessly to a load display device 5 as shown in FIG. 2B. It is. The load display device 5 displays, for example, the load measurement values as they are or displays the ratio between the load measurement values.

As described above, the load measuring device according to the embodiment of the present invention has been described, but the present invention is not limited to the one described in the embodiment, and various design changes can be made within the scope of the matters described in the claims. Is possible.

DESCRIPTION OF SYMBOLS 1 Load measuring device 2 Load sensor part 21 1st sheet-like elastic body 22 2nd sheet-like elastic body 21s The space | gap or hollow of 1st sheet-like elastic body 23 1st sheet-like conductive elastic body 23t 1st Sheet-like conductive elastic body terminals 24a to 24d A plurality of second sheet-like conductive elastic bodies 24at to 24dt A plurality of second sheet-like conductive elastic body terminals 25 Third sheet-like conductive elastic bodies 25t First 3 Sheet-like conductive elastic body terminals 3 Electrical circuit section 31 First AC output circuit 32 Second AC output circuit 33a to 33d Current measurement circuit 4 Footwear 4a Inner bottom 5 Load display device Ca ₁ to Cd ₁ a first capacitor Ca ₂ ~ Cd ₂ a plurality of second capacitors Ia ₁ ~ Id ₁ more first alternating current Ia ₂ ~ Id ₂ a plurality of second capacitor flowing through the capacitor AC alternating current Ia 3 _~ Id ₃ a plurality of second alternating current V ₁ first AC output circuit that flows through the terminal of the sheet-like conductive elastic body is output AC voltage V ₂ second AC output circuit outputs Voltage Va ~ Vd Load measurement voltage

Claims

A first sheet-like elastic body provided with a plurality of voids or depressions periodically and a flat second sheet-like elastic body made of the same material as a dielectric, and a first sheet-like conductive elastic body, A plurality of second sheet-like conductive elastic bodies sandwiching the first sheet-like elastic body between the first sheet-like conductive elastic bodies and the plurality of second sheet-like conductive bodies A load provided on the inner bottom of the footwear, wherein a plurality of capacitors are formed by using the second sheet-like conductive elastic body sandwiching the second sheet-like elastic body between the elastic body and an electrode. A sensor unit;
A first AC output circuit for applying an AC voltage to a terminal of the first sheet-like conductive elastic body; a second AC output circuit for applying an AC voltage to a terminal of the third sheet-like conductive elastic body; And an electric circuit unit having a current measurement circuit that measures each alternating current flowing through the terminals of the plurality of second sheet-like conductive elastic bodies and converts each alternating current into a respective load measurement voltage. Load measuring device.
In the load measuring device according to claim 1,
The plurality of second sheet-like conductive elastic bodies are in the shape of a single-layer sheet-like conductive elastic body divided into a plurality of thin groove portions.
In the load measuring device according to claim 1 or 2,
The plurality of second sheet-like conductive elastic bodies are four of a thumb side front part, a little finger side front part, a thumb side rear part, and a little finger side rear part.