JP2013210368A - Triaxial load measuring sensor by pressure-sensitive conductive material, tensile load measuring sensor and built-in type load measuring sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a triaxial load measuring sensor using an elastic body capable of measuring load, a load application position and a load direction, to provide a triaxial load measuring sensor capable of measuring also compression and tensile load, and to provide a built-in type triaxial load measuring sensor.SOLUTION: The triaxial load measuring sensor capable of measuring load, a load application position and a load direction by applying the pressure-sensitive conductive material includes the elastic body for receiving load, an upper electrode formed by electrodes of one or more surfaces, the pressure-sensitive conductive material and a lower electrode. The pressure-sensitive conductive material and the upper electrode are laminated on the lower electrode, the elastic body is placed on the upper electrode, and the load detects and measures voltage variations dV, dVto dVof respective zones to be changed by the load received by the pressure-sensitive conductive material through the elastic body.

Description

The present invention relates to a triaxial load measurement sensor, a tensile load measurement sensor, and a built-in load measurement sensor using a pressure-sensitive conductive material. More specifically, the present invention relates to a load and a load load position to which a pressure-sensitive conductive material is applied. And triaxial load measurement sensor that can measure the load direction,
It is possible to measure arbitrarily from high load to low load, and also to measure and cut the load from all directions by dispersing the tensile load measurement sensor that can also measure the tensile load and the pressure detector in the elastic body. Also relates to a built-in load measuring sensor capable of measuring the load.

Currently, robots are being developed and introduced in the fields of medical care, nursing care and welfare, and robot hands intended for application to artificial hands and humanoid robots are being developed. The robot hand needs to have the ability to grip objects of different hardness and shape. However, since the surface of the robot hand is made of metal, there is a risk of damaging the object to be gripped when a high load is applied. Also, it is necessary to measure and control the magnitude of the load, the position where the load is applied, and the direction of the load in order to prevent the object to be gripped from falling off.
Therefore, it is possible to flexibly deform the fingertip of the robot hand, measure the magnitude of the load, the position where the load is applied, and the direction of the load, and attach a sensor whose sensing surface is a curved surface such as a hemisphere similar to the shape of the fingertip. Necessary.

As such a sensor, there is a triaxial load measuring flexible contact sensor made of a pressure-sensitive conductive material and an elastic body. This sensor can measure the applied load by separating it into a vertical component and a shear component. Furthermore, the elastic body can detect a load by using a shape such as a sphere, a hemisphere, or a cylinder. However, this sensor load measurement principle has a problem that only a load applied to a position on the center axis of the sensor can be measured.
Further, only the compressive load and the shear load can be measured by the conventional sensor, and the tensile load cannot be measured. In addition, there is a problem that it is not possible to measure a wide range such as "high load" that holds a person and "low load" that enables delicate work of fingertips, and it can measure arbitrarily from high load to low load, In addition, the development of a triaxial load measuring sensor capable of measuring a tensile load has been desired.

Furthermore, endoscopic laparoscopic surgery in the medical field is quicker because it reduces the burden on the patient without cutting the body with a scalpel as in open surgery, leading to early recovery and early discharge after surgery. Has become popular.
However, in laparoscopic surgery, there is a problem that an excessive load is applied to an organ and a laceration is generated by using a fine insulator. Therefore, there is an urgent need to develop an elastic organ model having a load measurement sensor suitable for a surgical training system.
Currently, no sensor is attached to the organ for training, and the displacement is measured by image processing and the load is calculated. However, there is a problem that the error of the load is large. Therefore, it is necessary to develop a sensor capable of measuring pressure even when an organ model is excised with an electric knife or the like and hemostasis is performed.

JP 2007-187502 A

The present invention has been made to solve the above-mentioned problems, and is a triaxial load measuring sensor using a hemispherical elastic body capable of measuring a load, a load load position and a load direction, from a high load to a low load. It is an object of the present invention to provide a sensor for measuring a tensile load that can be arbitrarily measured and also capable of measuring a tensile load, and a sensor for measuring a built-in load that can measure a load even when an organ model is excised and hemostasis is performed.

In order to solve the above problems, the present invention is a triaxial load measuring sensor capable of measuring a load, a load load position, and a load direction by applying a pressure-sensitive conductive material, and an elastic body that receives the load; An upper electrode formed from one or a plurality of electrodes, a pressure-sensitive conductive material, and a lower electrode formed from one or a plurality of electrodes , the pressure-sensitive conductive material on the lower electrode The upper electrode and the lower electrode are stacked upside down, and the upper electrode and the lower electrode are stacked upside down, or the upper electrode and the lower electrode are stacked upside down. In this case, the elastic body is placed on the lower electrode, and the load is a circuit in which a circuit formed by each electrode of the upper electrode and a fixed resistor connected to each electrode is connected in parallel. Through the elastic body The voltage change amount of the respective zones sensitive conductive material changes by the load experienced by the dV _1, dV _{2, ···,} and measuring by detecting dV _m.

  The elastic body can be arbitrarily changed in shape, size, and hardness.

また、ａ_α、β、ｂ_ｉおよびｊはセンサの感度によって変化する変数であり、ｍは上部電極の数によって変化する変数である。 Of the triaxial loads, the vertical load P _n can be calculated by (Equation 1).

_Further, a α, β, b _i and j are variables that vary depending on the sensitivity of the sensor, m is a variable that varies depending on the number of the upper electrode.

ここで、Ｖ_ｘは前記各ゾーンの電圧変化量ｄＶ_１、ｄＶ_２、・・・、ｄＶ_ｍにそれぞれのｘ成分を乗じたものの総和。Ｖ_ｙは前記各ゾーンの電圧変化量ｄＶ_１、ｄＶ_２、・・・、ｄＶ_ｍにそれぞれのｙ成分を乗じたものの総和。 Among the triaxial loads, the shear load Pt can be obtained from the voltage change ΔV as shown in (Equation 2).

Here, V _x is the total sum of the voltage change amounts dV ₁ , dV ₂ ,..., DV _m of each zone multiplied by the respective x components. _Vy is the sum of voltage changes dV ₁ , dV ₂ ,..., DV _m of each zone multiplied by the respective y components.

The angle φ from the zone 1 where the load is applied can be calculated by (Equation 3).

ここで、ζとｄψはセンサの感度により変化する変数である。 The pushing amount Δh in the z direction can be calculated by (Equation 4) by the vertical load P _n .

Here, ζ and dψ are variables that change depending on the sensitivity of the sensor.

ここで、σとｅ_ωはセンサの感度によって変化する変数である。 The distance Δr from the center of the triaxial load measuring sensor to which the load is applied can be calculated by (Equation 5).

Here, σ and e _ω are variables that change depending on the sensitivity of the sensor.

Further, the present invention is a triaxial load measuring sensor capable of measuring a compression and tensile load by applying a pressure-sensitive conductive material, a load cradle for receiving a load whose elastic body is covered with an elastic film, An upper electrode formed from one or a plurality of electrodes, a pressure-sensitive conductive material, and a lower electrode formed from one or a plurality of electrodes , the pressure-sensitive conductive material on the lower electrode The upper electrode and the lower electrode are stacked upside down, and the upper electrode and the lower electrode are stacked upside down, or the upper electrode and the lower electrode are stacked upside down. In this case, the load cradle is placed on the lower electrode, the elastic film is bonded to the elastic body, and a preload is applied to the conductive material through the elastic film and the elastic body, The compression and tensile loads are In a circuit in which a circuit formed from each electrode of a partial electrode and a fixed resistor connected to each electrode is connected in parallel, the amount of voltage change in each zone that varies depending on the load received by the pressure-sensitive conductive material through the elastic body It is characterized by detecting and measuring dV ₁ , dV ₂ ,..., dVm.

また、ａ_α、β、ｂ_ｉおよびｊはセンサの感度によって変化する変数であり、ｍは上部電極の数によって変化する変数である。 The vertical load Pn among the triaxial loads can be expressed by a voltage change amount or a total V of each zone as shown in ( Expression 6) , and the compressive and tensile loads according to claim 8 can be measured. Triaxial load measurement sensor

_Further, a α, β, b _i and j are variables that vary depending on the sensitivity of the sensor, m is a variable that varies depending on the number of the upper electrode.

Further, the present invention is a built-in triaxial load measuring sensor that can measure a load even if it is cut by applying a pressure-sensitive conductive material and dispersing a load detection unit in an elastic body. An elastic body for receiving the upper electrode, an upper electrode formed from one or more electrodes, a pressure-sensitive conductive material, and a lower electrode formed from one or more electrodes. The load-sensitive conductive material and the upper electrode are stacked on top of each other, or a load detection unit in which the upper electrode and the lower electrode are stacked upside down is housed in an elastic body, and the load is In a circuit in which a circuit formed from each electrode of the upper electrode and a fixed resistor connected to each electrode is connected in parallel, the amount of voltage change in each zone that varies depending on the load received by the pressure-sensitive conductive material through the elastic body dV1, dV2, ..., characterized in that it measured by detecting the dVm.

According to the present invention, the amount of indentation in the z direction can be determined from the vertical load, the angle from the zone 1 where the load is applied, the distance from the sensor center, and the vertical load by measuring the relationship between the voltage changes in each zone. it can.
In addition, it can measure arbitrarily from high load to low load, and in addition, it can measure tensile load, and can measure load even when organ model is excised and hemostasis is performed.

It is a block diagram of the sensor for triaxial load measurement of this invention. It is a front view of the sensor for triaxial load measurement of the present invention. It is a top view of the sensor for triaxial load measurement of this invention. It is a figure which shows the structure of the load detection layer of the sensor for triaxial load measurement of this invention. It is the schematic which shows the system for triaxial load measurement of this invention. It is a circuit diagram of the sensor for triaxial load measurement of the present invention. It is a figure which shows the relationship between the vertical load Pn when the distance (DELTA) r from a sensor center is changed, and the sum total V of the amount of voltage changes of each zone. It is a figure which shows the relationship with the voltage changes Vx and Vy when (DELTA) r = 15mm. It is a figure which shows the relationship between the vertical load Pn in (DELTA) r, and pushing amount (DELTA) h of z direction. It is a figure which shows the relationship between the sum total V of the voltage change of each zone at the time of changing distance (DELTA) r from a sensor center, and voltage change (DELTA) V. It is sectional drawing of the sensor for tensile load measurement of this invention. It is a figure which shows the loading method to the sensor for tensile load measurement of this invention. It is a figure which shows the relationship between the sum V of the voltage variation of each zone, and the tensile load Pt. It is a figure which shows the relationship between the sum V of the voltage variation of each zone, and the compression load Pn. It is a figure explaining the effect of the built-in type load measuring sensor of the present invention. It is a figure which shows the pressure detection part of the sensor for built-in type load measurement of this invention. It is a figure which shows the structure of the Example of the built-in type load measuring sensor of this invention. It is an external view of the Example of the built-in type load measuring sensor of this invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
1 is a configuration diagram of a triaxial load measuring sensor of the present invention, FIG. 2 is a front view of the triaxial load measuring sensor of the present invention, and FIG. 3 is a plan view of the triaxial load measuring sensor of the present invention. 4 is a diagram showing the configuration of the load detection layer of the triaxial load measuring sensor of the present invention, and FIG. 5 is a schematic diagram showing the triaxial load measuring system of the present invention.

As shown in FIG. 2 , the triaxial load measuring sensor 1 of the present invention includes a hemispherical elastic body 2 that receives a load, a positive zone 1 in the X axis, a positive zone 2 in the Y axis, and a negative X axis. The upper electrode 3 formed from the respective electrodes of the direction zone 3 and the negative direction zone 4 of the Y-axis, the pressure-sensitive conductive material 4 obtained by adding vapor-grown carbon fiber to polycarbonate (PC), the lower electrode 5, It is composed of
As shown in FIG. 2, the triaxial load measuring sensor 1 has a pressure-sensitive conductive material 4 and an upper electrode 3 stacked on a lower electrode 5 and a hemispherical elastic body 2 mounted on the upper electrode 3. Is formed.

As the upper electrode 3, a polyimide flexible substrate is used . By etching, as shown in FIG. 4 , a zone 1 in the positive direction of the X axis, a zone 2 in the positive direction of the Y axis, and a zone in the negative direction of the X axis. 3. Each electrode of the zone 4 in the negative direction of the Y axis is formed, and as shown in FIG. 5, a fixed resistor is connected to each of the four electrodes to form a circuit shown in FIG.
On the other hand, a glass epoxy positive photosensitive substrate is used for the lower electrode 5, and the lower electrode 5 (second electrode portion) is provided on the upper surface of the lower electrode 5 by etching. Each upper and lower electrode is provided with a terminal for connection to an external device.
The load varies depending on the load received by the pressure-sensitive conductive material 4 through the hemispherical elastic body 2 in a circuit in which a circuit formed by each electrode in zones 1 to 4 and a fixed resistor connected to each electrode is connected in parallel. The voltage change amounts dV1, dV2, dV3, and dV4 in each zone are detected and measured.

FIG. 5 shows a triaxial load measuring system 6 of the present invention.
As shown in FIG. 5, the triaxial load measuring system 6 of the present invention is a voltage detector 8 that detects the voltage of each zone, and performs calculation processing by taking in the voltage detection value from the voltage detector 8. An arithmetic processor 9 and a stabilized power source 7 for supplying a voltage to the upper and lower electrodes are provided.

Next, examples of the present invention will be described.
In this embodiment, the hemispherical elastic body 2 of the triaxial load measuring sensor 1 is prepared by mixing liquid silicon and a curing agent at a mass ratio of 9: 1 and adding thinner, and has flexibility and elastic restoration. It was supposed to have a sex. The Young's modulus can be changed by adding thinner. In the hemispherical elastic body 2 of this example, 40% of thinner was added by mass ratio, Young's modulus was 0.404 MPa, and Poisson's ratio was 0.492. The material of the hemispherical elastic body 2 is not limited to the above materials, and for example, polymer materials such as rubber, epoxy resin, polypropylene (PP), polyethylene (PE), and polyacetal (POM) are applicable. is there. The diameter of the sphere of the hemispherical elastic body 2 is 60 mm, but the size can be arbitrarily changed.

The pressure-sensitive conductive material 4 is PC / 20 wt% VGCF obtained by adding 20% by mass of vapor-grown carbon fiber (VGCF) to polycarbonate (PC). The size is 65 × 65 mm and the thickness is 0.1 mm. is there.
PC / VGCF has the property that the electrical resistance value changes when a load is applied, and the voltage between the upper and lower electrodes changes. Therefore, when the total amount of voltage change in each zone is V, the voltage change in each zone The vertical load can be measured by measuring the amount.
As the upper electrode 3, a flexible substrate made of polyimide is used, and four electrodes as shown in FIG. 1 are provided on the lower surface of the upper electrode 3 by etching.
On the other hand, a glass epoxy positive photosensitive substrate is used for the lower substrate 32, and a lower electrode is provided by etching. In addition, you may arrange | position the deformation | transformation form which turned the upper electrode 3 and the lower electrode 5 upside down, ie, the lower board | substrate 5 which has a single-surface electrode on the upper side, and the upper electrode 3 isolate | separated into four on the lower side.

Next, a method for calculating the push amount in the z direction from the vertical load, the angle from the zone 1 where the load is applied, the distance from the sensor center, and the vertical load will be described.
First, a method for measuring the vertical load will be described.
FIG. 7 shows the relationship between the vertical load Pn and the total voltage change amount V of each zone when the distance Δr from the sensor center is changed. The relationship between the vertical load Pn when Δr = 0 in FIG. 7 and the sum V of the amount of voltage change in each zone is a master curve, and the master curve is multiplied by a coefficient c so that the vertical load Pn at a distance Δr from the sensor center is obtained. And the sum V of the amount of voltage change in each zone is obtained.

Δｒ＝０、５、１０、１５ｍｍより求めた係数ｃとセンサ中心からの距離Δｒの関係を最小二乗法を用い２次関数で近似した結果を（数１１）に示す。
［数１１］
ｃ ＝ｂ１Δｒ^２−ｂ２Δｒ十ｌ
ｂ１＝０．００１６２３、ｂ２＝０．００７３７
_{Assuming that} the total amount of voltage change in each zone when the vertical load Pn = 40 N at each distance Δr is V _{Δr, the coefficient c can be obtained from (Equation 10) and is as follows.}

(Equation 11) shows the result of approximating the relationship between the coefficient c obtained from Δr = 0, 5, 10, 15 mm and the distance Δr from the sensor center with a quadratic function using the least square method.
[Equation 11]
c = b1Δr ² −b2Δr + l
b1 = 0.001623, b2 = 0.00737

Next, when the master curve is approximated by a quintic function using the least square method, (Equation 12) is obtained.
[Equation 12]
Pn = a ₁ V ^{5 + a} ₂ V ⁴ + a _3V ³ + a ₄ V ² + a ₅ V
a ₁ = 0. 00005505, ^a _{2 = -0} . 00157, a ₃ = 0.017, a ₄ = 0.05164, a ₅ = 0.7717

By applying the coefficient c to (Equation 12), a vertical load Pn applied to the position of Δr is obtained as shown in (Equation 13).
[Equation 13]
Pn = a ₁ (cV _Δr ) ^{5 + a} ₂ (cV _Δr ) ⁴ + a ₃ (cV _Δr ) ³ + a ₄ (cV _Δr ) ² + a ₅ (cV _Δr )
a ₁ = 0.00005505, ^a ₂ = -0.001157, a ₃ = 0.017, a ₄ = -0.05164, a ₅ = 0.7717

Next, a method for calculating the angle from zone 1 where the load is applied will be described.
FIG. 8 shows the relationship between the voltage changes Vx and Vy when Δr = 15 mm.
If the x and y components of the voltage change are Vx and Vy, Vx and Vy are as follows (Equation 14).
[Formula 14]
Vx = dV1-dV3, Vy = dV2-dV4

The relationship between the angle φ from the zone 1 and the voltage changes Vx and Vy is as shown in (Equation 15), and the angle φ from the zone 1 can be obtained.

Next, how to determine the push amount Δh in the z direction will be described.
FIG. 9 shows the relationship between the vertical load Pn at Δr and the pushing amount Δh in the z direction.
It can be seen that the relationship between the vertical load Pn and the pushing amount Δh in the z direction does not change even when Δr changes.
When the relationship between the vertical load Pn and the pushing amount Δh in the z direction is approximated by a cubic function using the least square method, (Equation 16) is obtained.
[Equation 16]
Δh = d ₁ Pn ^{3 + d} ₂ ^{Pn2 + d} ₃ ^Pn
d ₁ = 0.00005323, ^d ₂ = ^{0.008308, d} ₃ ^{= 0.5965}

By substituting the vertical load Pn into Equation 16, the pushing amount Δh in the z direction can be obtained.

図１０にセンサ中心からの距離Δｒを変えた場合の各ゾーンの電圧変化の総和Ｖと電圧変化ΔＶの関係を示す。
最小二乗法により１次関数で近似すると勾配ｋが（数１８）の通り得られる。
［数１８］
ｋ＝ΔＶ／Ｖ

この関係を用いてセンサ中心からの距離Δｒと係数ｋ の関係が図１１の通り得られる。この関係から最小二乗法により二次関数で近似し、（数１９）が得られる。

ｅ１＝−７０．５４、ｅ２＝７０．５０
電圧変化ΔＶと各ゾーンの電圧変化の総和Ｖを測定することで（数１９）によりセンサ中心からの距離Δｒを求めることが出来る。 Next, how to obtain the distance Δr from the sensor center will be described.
The voltage change ΔV can be expressed as follows using (Equation 17).

FIG. 10 shows the relationship between the total voltage change V of each zone and the voltage change ΔV when the distance Δr from the sensor center is changed.
When approximated by a linear function by the method of least squares, a gradient k is obtained as (Equation 18).
[Equation 18]
k = ΔV / V

Using this relationship, the relationship between the distance Δr from the sensor center and the coefficient k is obtained as shown in FIG. From this relationship, approximation by a quadratic function is performed by the method of least squares to obtain (Equation 19).

e1 = −70.54, e2 = 70.50
By measuring the voltage change ΔV and the sum V of the voltage changes in each zone, the distance Δr from the sensor center can be obtained by (Equation 19).

Next, the tensile load measuring sensor will be described.
As shown in FIG. 11, the tensile load measuring sensor 11 includes a load receiving base 15 for receiving a load in which the elastic bodies 12 and 13 are covered with the elastic film 14, a zone 1 in the positive direction of the X axis, and a positive direction of the Y axis. Zone electrode 2, negative electrode zone 3 in the X axis, and upper electrode 16 formed from the negative electrode zone 4 in the Y axis, and pressure-sensitive conductivity obtained by adding vapor-grown carbon fiber to polycarbonate (PC) It consists of a material 17 and a lower electrode 18.
The elastic bodies 12 and 13 can be arbitrarily changed in shape, size, aspect ratio, and hardness, but in the embodiment, those obtained by combining the hemispherical elastic bodies 12 of the cylindrical elastic bodies 13 are used.
A pressure-sensitive conductive material 17 and an upper electrode 16 are stacked on the lower electrode 18, and a load receiving base 15 including the elastic bodies 12 and 13 and the elastic film 14 is placed on the upper electrode 16. The load receiving base 15 is covered with the elastic film 14, and the entire circumference of the elastic film 14 is bonded to the upper surface of the upper electrode 16, and the elastic film 14 preloads the pressure-sensitive conductive material 17 through the elastic bodies 12 and 13. ing.
The compressive and tensile loads are applied to the circuit shown in FIG. 6 and the triaxial load measuring system shown in FIG. 5 in which the circuits formed from the electrodes in zones 1 to 4 and the fixed resistors connected to the electrodes are connected in parallel. The voltage change amounts dV1, dV2, dV3, and dV4 of each zone that change depending on the load received by the pressure-sensitive conductive material 17 through the elastic bodies 12 and 13 are detected and measured.

As shown in FIG. 12, the tensile load measuring sensor 11 uses an elastic film 14, and the elastic film 14 applies a preload to the pressure-sensitive conductive material 17 through the elastic bodies 12 and 13, thereby measuring the tensile load. It is possible.
With respect to the sensor 11 for measuring the tensile load, a state in which a compression preload is applied by the elastic film 14 is set as an offset value, and when the preload is removed by the tensile load, the removed tensile load can be measured.
That is, as shown in FIG. 12, by pulling an arbitrary position on the z-axis of the elastic body, the preload applied to the sensor is removed, and the tensile load can be measured.
In the embodiment, the load detecting unit sandwiches a 12 mm square pressure-sensitive conductive resin (PC / 20 wt% VGCF) between the upper and lower electrodes 16 and 18, and the cylindrical elastic body 13 having a diameter of 10 mm and a height of 10 mm is formed on the upper part thereof. A hemispherical elastic body 12 having a radius of 5 mm is installed, and an upper portion of the hemispherical elastic body 12 is covered with a rubber film as an elastic film 14 so as to apply an excess load.
As shown in FIG. 13, when the tensile load is applied, the sum V of the voltage change amount of each zone decreases.
Further, when compressed, the sum V of the amount of voltage change increases as shown in FIG.

従って、センサに負荷される任意の荷重Ｐは各ゾーンに負荷される荷重Ｐｍ（ｍ＝１、 ２、３、４）の総和、およびｘ、ｙ、 ｚ成分に分解することができ、これをＰｘ、Ｐｙ、Ｐｚとすれば任意の荷重Ｐは（数２１）のように表すことができる．

Next, a method for measuring tensile and compressive loads by the tensile load measuring sensor 11 will be described.
The voltage in each zone is Vm (m = 1, 2, 3, 4). Here, the difference between the power supply voltage Vo and the voltage Vm of each zone is defined as a voltage change amount dVm (m = 1, 2, 3, 4), and the load applied to each zone is Pm (m = 1, 2, 3). 4) Then, Pm can be expressed as a vector as shown in (Equation 20).

Therefore, an arbitrary load P applied to the sensor can be decomposed into a sum of loads Pm (m = 1, 2, 3, 4) applied to each zone, and x, y, and z components. If Px, Py, Pz, an arbitrary load P can be expressed as (Equation 21).

The vertical load Pn is Pn = Pz from (Equation 21), and is the sum of each zone voltage change amount dVm (m = 1, 2, 3).
Here, assuming that the total amount of voltage change in each zone is V, Pn is as shown in (Equation 22), and the magnitude of the vertical load Pn can be obtained from the voltage change amount in each zone. The shear load Pt can be obtained by obtaining the magnitudes of the x and y components of the arbitrary load P. Here, Px and Py are expressed as Vx and Vy as in (Equation 23) and (Equation 24) using the voltage change amount dVm (m = 1, 2, 3, 4) of each zone from (Equation 21). Can do.
Therefore, the shear load Pt can be obtained by obtaining the voltage change ΔV as shown in (Equation 25).

Next, the built-in load measuring sensor 21 will be described.
The built-in load measuring sensor 21 includes an elastic body 22 that receives a load, a positive zone 1 of the X axis, a positive zone 2 of the Y axis, a negative zone 3 of the X axis, and a negative zone of the Y axis. It consists of an upper electrode 24 formed from each electrode in zone 4, a pressure-sensitive conductive material 25 in which vapor-grown carbon fiber is added to polycarbonate (PC), and a lower electrode 26.
A pressure-sensitive conductive material 25 and an upper electrode 24 are laminated on the lower electrode 26, and the laminated load detection unit 23 is accommodated inside the elastic body 22.
The load is a circuit of the triaxial load measuring system of FIG. 5 and the circuit of the triaxial load measuring sensor of FIG. 6 in which circuits formed from the respective electrodes of zones 1 to 4 and fixed resistors connected to the respective electrodes are connected in parallel. In the figure, voltage change amounts dV1, dV2, dV3, and dV4 in each zone that change depending on the load received by the pressure-sensitive conductive material 25 are detected and measured.
The method for measuring the compressive load Pn and the tensile load Pt of the built-in load measuring sensor is the same as that of the sensor for measuring the tensile load, and is omitted.

This built-in type load measuring sensor is a sensor that can measure a load even when it is cut by dispersing a load detecting portion in an elastic body, and its features are as follows.
1. It is a three-dimensional structure (FIG. 15A) in which a large number of polyhedron load detection units are arranged inside an elastic body.
2. FIG. 15B shows a sensor (FIG. 15B) that can obtain a compression load vector P by forceps from loads in respective directions of a plurality of load detectors when a load is applied.
3. Furthermore, it is a sensor that can cut the elastic body by applying a voltage to the forceps while applying a load, and the remaining sensor can continue to measure the load (FIG. 15C).

FIG. 16 shows a load detection unit of the built-in load measuring sensor. FIG. 16 shows only the upper surface, but if the load detection unit is a cube, conductive materials are arranged between the upper electrode and the lower electrode on all six surfaces. However, it is not always necessary to arrange on all surfaces, and it may be arranged on only one surface or two surfaces.
The load detection unit may be a cube, a rectangular parallelepiped, a triangular pyramid, a quadrangular pyramid, a sphere, or a polyhedron.
The load vector can be measured by utilizing the fact that the conductive material is deformed and the resistance value is changed by applying a load.
Although the upper electrode and the lower electrode in FIG. 16 are one surface at a time, each of them can be divided into a plurality of parts, and the vertical load and the shear load can be measured by the division.
These load detection units are covered with an elastic body, and the shape of the elastic body may be a sphere, a cube, a rectangular parallelepiped, an ellipse, a cone, a pyramid, or a polyhedron.

FIG. 17 shows an embodiment of a built-in load measuring sensor.
In this example, a load detecting unit made of a cube having a side of 30 mm was produced, and the periphery thereof was covered with an elastic sphere having a diameter of 60 mm. FIG. 18 shows the appearance of the actually manufactured sensor.
The load detection unit is composed of an upper electrode, a lower electrode, and a conductive resin. This time, a sensor with the upper electrode divided into four was produced. The conductive resin is PC / 20 wt% VGCF.

According to the triaxial load measuring sensor of the present invention, the vertical load, the angle from the zone 1 where the load is applied, and the distance from the sensor center are obtained by measuring the voltage change amount of each zone. The amount of pushing in the z direction is determined from the load.
The tensile load measuring sensor is covered with a rubber-like film (plate) whose elastic body is elastically deformed, and a compression preload is applied by the film. Conventional flexible contact sensors have no preload for compression and therefore cannot measure tensile load, but this sensor can measure compression and tensile vertical load.

Furthermore, since the voltage change can be analyzed instantaneously, the load can be measured instantaneously, and the sensor itself has a thickness of several millimeters, so that the size can be reduced.
In addition, the tensile load measurement sensor can measure from a high load to a low load by controlling the sensitivity (load and voltage change) of the conductive resin.
Therefore, the resin material, which is the base material, is changed variously, such as crystalline resin, amorphous resin, thermoplastic resin, thermosetting resin, etc. Furthermore, the conductive material is not only CNT but also carbon black, carbon fiber, graphite In addition, a material in which metal powder or the like is dispersed is also used.

  For this built-in load measuring sensor, the pressure detectors are dispersed in the elastic body so that the load can be measured even after cutting, and a large number of polyhedral pressure detectors are arranged inside the elastic body. In addition, when a load is applied, the compression load vector P by the forceps can be obtained from the loads in the respective directions of the plurality of load detectors. The elastic body can be cut and the remaining sensor can continue to measure the load.

DESCRIPTION OF SYMBOLS 1 Triaxial load measurement sensor 2 Hemispherical elastic body 3 Upper electrode 4 Pressure sensitive conductive material 5 Lower electrode 6 Three-dimensional load measurement system 7 Stabilized power supply 8 Voltage detector 9 Arithmetic processor 11 Tensile load measurement sensor 12 Hemispherical elastic body 13 Cylindrical elastic body 14 Elastic film 15 Load receiving base 16 Upper electrode 17 Pressure-sensitive conductive material 18 Lower electrode 21 Built-in load measuring sensor 22 Elastic body 23 Load detector 24 Upper electrode 25 Pressure-sensitive conductive material 26 Lower electrode

Claims (21)

A triaxial load measurement sensor capable of measuring a load, a load load position, and a load direction by applying a pressure-sensitive conductive material,
An elastic body that receives the load;
An upper electrode formed of one or more electrodes,
A pressure sensitive conductive material;
A lower electrode formed of one or more electrodes,
Including
Laminating the pressure-sensitive conductive material and the upper electrode on the lower electrode, or laminating the upper electrode and the lower electrode upside down,
If the upper electrode and the lower electrode are stacked upside down on the upper electrode, the elastic body is placed on the lower electrode.
The load varies according to the load received by the pressure-sensitive conductive material through the elastic body in a circuit in which a circuit formed from each electrode of the upper electrode and a fixed resistor connected to each electrode is connected in parallel. A sensor for measuring a triaxial load, characterized by detecting and measuring a voltage change amount dV ₁ , dV ₂ ,..., DV _m in a zone.   The triaxial load measuring sensor according to claim 1, wherein the elastic body can be arbitrarily changed in shape, size, and hardness. The sensor for measuring triaxial load according to claim 1, wherein the vertical load P _n of the triaxial loads can be calculated by (Equation 1).

_Further, a α, β, b _i and j are variables that vary depending on the sensitivity of the sensor, m is a variable that varies depending on the number of the upper electrode. 2. The triaxial load measuring sensor according to claim 1, wherein the shear load Pt among the triaxial loads can be obtained from the voltage change ΔV as shown in (Expression 2).

Here, V _x is the total sum of the voltage change amounts dV ₁ , dV ₂ ,..., DV _m of each zone multiplied by the respective x components. _Vy is the sum of voltage changes dV ₁ , dV ₂ ,..., DV _m of each zone multiplied by the respective y components. The sensor for measuring a triaxial load according to claim 1, wherein the angle φ from the zone 1 to which the load is applied can be calculated by (Equation 3).

2. The triaxial load measurement sensor according to claim 1, wherein the push amount Δh in the z direction can be calculated by (Equation 4) based on the vertical load P _n .

Here, ζ and d _ψ are variables that change depending on the sensitivity of the sensor. 2. The triaxial load measurement sensor according to claim 1, wherein the distance Δr from the center of the triaxial load measurement sensor to which the load is applied can be calculated by (Equation 5).

Here, σ and e _ω are variables that change depending on the sensitivity of the sensor. A triaxial load measuring sensor capable of measuring compression and tensile load by applying a pressure sensitive conductive material,
A load cradle for receiving a load whose elastic body is covered with an elastic film;
An upper electrode formed of one or more electrodes,
A pressure sensitive conductive material;
A lower electrode formed of one or more electrodes,
Including
Laminating the pressure-sensitive conductive material and the upper electrode on the lower electrode, or laminating the upper electrode and the lower electrode upside down,
When the upper electrode and the lower electrode are stacked upside down on the upper electrode, the load receiving base is placed on the lower electrode, and the elastic film is bonded to the elastic body. A preload is applied to the conductive material through the elastic membrane and the elastic body,
The compressive and tensile loads vary depending on the load received by the pressure-sensitive conductive material through the elastic body in a circuit in which a circuit formed from each electrode of the upper electrode and a fixed resistor connected to each electrode is connected in parallel. the voltage variation dV 1 in each _zone, dV _{2, ···,} triaxial load measuring sensors compressive and tensile load is measurable and measuring by detecting dVm to. The triaxial load measuring sensor capable of measuring a compression and a tensile load according to claim 8 , wherein the elastic body can be arbitrarily changed in shape, size, and hardness. The vertical load Pn among the triaxial loads can be expressed by a voltage change amount or a total V of each zone as shown in ( Expression 6) , and the compressive and tensile loads according to claim 8 can be measured. Triaxial load measurement sensor

_Further, a α, β, b _i and j are variables that vary depending on the sensitivity of the sensor, m is a variable that varies depending on the number of the upper electrode. 9. The triaxial load measuring sensor capable of measuring compressive and tensile loads according to claim 8, wherein the shear load Pt of the triaxial loads can be obtained from a voltage change ΔV as shown in (Expression 7).

Here, V _x is the total sum of the voltage change amounts dV ₁ , dV ₂ ,..., DV _m of each zone multiplied by the respective x components. _Vy is the sum of voltage changes dV ₁ , dV ₂ ,..., DV _m of each zone multiplied by the respective y components. 9. The triaxial load measuring sensor according to claim 8 , wherein the angle φ from the zone 1 to which the load is applied can be calculated by (Equation 3).

9. The triaxial load measuring sensor according to claim 8 , wherein the push amount Δh in the z direction can be calculated by (Equation 4) based on the vertical load P _n .

Here, ζ and d _ψ are variables that change depending on the sensitivity of the sensor. 9. The triaxial load measuring sensor according to claim 8 , wherein the distance Δr from the center of the triaxial load measuring sensor to which the load is applied can be calculated by (Equation 5).

Here, σ and e _ω are variables that change depending on the sensitivity of the sensor. A built-in triaxial load measuring sensor that can measure the load even after cutting by applying a pressure-sensitive conductive material and dispersing the load detection part in the elastic body,
An elastic body that receives the load;
An upper electrode formed of one or more electrodes,
A pressure sensitive conductive material;
A lower electrode formed of one or more electrodes,
Including
The pressure-sensitive conductive material and the upper electrode are stacked on the lower electrode, or the load detection unit in which the upper electrode and the lower electrode are turned upside down is stored inside an elastic body,
The load varies according to the load received by the pressure-sensitive conductive material through the elastic body in a circuit in which a circuit formed from each electrode of the upper electrode and a fixed resistor connected to each electrode is connected in parallel. A built-in triaxial load measuring sensor characterized by detecting and measuring the voltage change amounts dV1, dV2, ..., dVm of the zone. 16. The built-in triaxial load measuring sensor according to claim 15 , wherein the elastic body can be arbitrarily changed in shape, size, and hardness. The built-in triaxial load measuring sensor according to claim 15 , wherein the vertical load Pn among the triaxial loads can be expressed by a voltage change amount or a total sum V of each zone as shown in ( Expression 1). .

_Further, a α, β, b _i and j are variables that vary depending on the sensitivity of the sensor, m is a variable that varies depending on the number of the upper electrode. The built-in triaxial load measuring sensor according to claim 15 , wherein the shear load Pt among the triaxial loads can be obtained from the voltage change ΔV as shown in (Equation 9).

Here, V _x is the total sum of the voltage change amounts dV ₁ , dV ₂ ,..., DV _m of each zone multiplied by the respective x components. _Vy is the sum of voltage changes dV ₁ , dV ₂ ,..., DV _m of each zone multiplied by the respective y components. 16. The triaxial load measuring sensor according to claim 15 , wherein the angle φ from the zone 1 to which the load is applied can be calculated by (Equation 3).

16. The triaxial load measuring sensor according to claim 15 , wherein the pushing amount Δh in the z direction can be calculated by (Equation 4) by the vertical load _Pn .

Here, ζ and d _ψ are variables that change depending on the sensitivity of the sensor. The triaxial load measuring sensor according to claim 15 , wherein the distance Δr from the center of the triaxial load measuring sensor to which the load is applied can be calculated by (Equation 5).

Here, σ and e _ω are variables that change depending on the sensitivity of the sensor.

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