JP3731051B2 - Sensor for measuring pressure distribution and frictional force distribution - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sensor for measuring a planar pressure distribution and a frictional force distribution.
[0002]
[Prior art]
As a planar pressure distribution measuring method, conventionally, a required number of load cells are arranged on a measurement surface, and the output thereof is appropriately amplified by an amplifier, and the present inventors have already disclosed Patent No. 2034846 (Patent No. As clarified in the literature 1), measurement is performed by arranging pressure-sensitive elements made of planar pressure-sensitive conductive rubber in a matrix and combining them with the required scanning circuit, switching circuit, signal processing circuit, etc. The method is known. Further, as already disclosed in Japanese Patent No. 2053811 (Patent Document 2), the present inventors configure the detection unit in a shape similar to a glove using the flexibility of the material in the latter method. Therefore, a method for measuring the operating force distribution of a human hand is also known.
[0003]
On the other hand, as a method for measuring the frictional force, a method using a three-component force meter using a load cell is generally widespread, and the present inventors have already made clear in Patent No. 1646028 (Patent Document 3). In addition, the friction coefficient is detected by measuring the displacement of the center of gravity position of the acting force by a pair of surface pressure sensors opposed to each other through the spacer of the elastic body, and the friction coefficient is added to the surface pressure measured separately. A method for measuring the frictional force by multiplying is known. In particular, if a large number of the above three component force meters are arranged, it is possible in some cases to simultaneously measure the pressure distribution and the frictional force distribution. For example, when one or both of the contact surfaces to be measured are flexible or fragile, such as when operating the , Could not respond.
[Patent Document 1]
Japanese Patent Publication No. 7-58223 [Patent Document 2]
Japanese Patent Publication No. 7-86439 [Patent Document 3]
Japanese Examined Patent Publication No. 3-47699
[Problems to be solved by the invention]
An object of the present invention is to provide a sensor for measuring pressure distribution and frictional force distribution, which is relatively simple in structure and can be made of a material having flexibility as necessary.
[0005]
[Means for Solving the Problems]
A sensor for measuring pressure distribution and frictional force distribution according to the present invention for solving the above-described problems is provided between a pair of pressure plates having a large number of concavities and convexities in a shape to be fitted to each other on the opposing surfaces, and the opposing surfaces of these pressure plates. The detection unit is configured by disposing the sandwiched sheet-like pressure-sensitive conductive material and arranging electrodes facing the concave and convex portions of the opposing surface of the pressure plate, for example, the top surface, the bottom surface, and the intermediate plane between them. The detection means for detecting the conductivity between the electrodes in each of the detection units is provided, and based on the detected conductivity, the pressure distribution acting in the direction perpendicular to the sensor surface which is the outer surface of the pressure plate and the sensor surface in parallel It is characterized in that the distribution of acting friction force can be measured.
[0006]
In addition, the sensor according to the present invention has a thin pressure detection element sandwiched between the opposing positions of the pressure plate in place of the sheet-like pressure-sensitive conductive material and electrodes in the sensor having the above-described configuration. The pressure acting on each part of the opposing surfaces of the pair of pressure plates is configured to be measurable.
That is, the sensor according to the present invention includes a pair of pressure plates having a large number of concavities and convexities that are fitted to each other on the opposing surface and the concavities and convexities of the confronting surfaces of the pressure plates, for example, between the top surface, the bottom surface, and their intermediate planes. And a detecting unit configured to detect a pressure detecting element output in each of the detecting units, and is an outer surface of the pressure plate based on the detected pressure. The pressure distribution acting in the direction perpendicular to the sensor surface and the frictional force distribution acting in parallel with the sensor surface can be measured.
[0007]
Furthermore, the sensor according to the present invention has a pressure distribution recording film between a pair of pressure plates having a large number of concavities and convexities that are fitted to each other in place of the pressure-sensitive conductive material and electrodes in the sensor having the above-described configuration. The planar pressure distribution and the frictional force distribution described above can be measured based on the recording of the pressure distribution recording film.
That is, the sensor of the present invention is a detection constituted by a pair of pressure plates having a large number of concavities and convexities that are fitted to each other on the opposing surface, and a pressure distribution recording film sandwiched between the opposing surfaces of the pressure plates. Based on the recording of the pressure distribution recording film, the pressure distribution acting in the direction perpendicular to the sensor surface, which is the outer surface of the pressure plate, and the friction force distribution acting in parallel with the sensor surface can be measured. It is characterized by that.
[0008]
In the sensor having the above configuration, for example, the concave and convex portions on the opposing surface of the pressure plate are not provided with the bottom surface and the top surface parallel to the sensor surface, and the concave and convex portions can be formed only by the inclined surfaces that are fitted to each other. A third surface parallel to the sensor surface can be provided in the middle of the unevenness of the opposing surface.
[0009]
According to the surface pressure distribution and friction force distribution measurement sensor having the above-described configuration, the sensor is mounted on the working surface of a work machine or the surface of a human body, and processing according to the arrangement state of each electrode or the like. By connecting the circuit, it is possible to simultaneously measure the pressure distribution and the frictional force distribution between the working surface and the object in contact with the body surface.
Further, when the pressure distribution recording film is used, similarly, the sensor is attached to the working surface of the work machine or the surface of the human body, the pressure recording film is taken out after the work, and the recorded pressure record is appropriately analyzed. Thus, the maximum pressure distribution and the maximum frictional force distribution between the working surface and the object in contact with the body surface can be measured.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described in detail below with reference to the drawings.
FIG. 1 is a cross-sectional view for explaining the detection principle of the present invention. The sensor according to the present invention is a sensor for measuring a planar pressure distribution and a frictional force distribution. In FIG. 1, the sensor is expressed as a one-dimensional one. It is constructed.
[0011]
The sensor shown in FIG. 1 is a sheet-like sandwiched between a pair of pressure plates 1 and 2 having a large number of concavities and convexities that fit into opposite surfaces, and the pressure plates 1 and 2 facing each other at substantially constant intervals. The pressure-sensitive conductive material 3 and the pressure plate 1 and 2 are opposed to each other with the pressure-sensitive conductive material 3 sandwiched between the concave and convex top surfaces 11 and the bottom surface 12 and the intermediate plane 13 therebetween. Detector A composed of electrode A ₁ and electrode A ₂ to be detected, detector B similarly composed of electrode B ₁ and electrode B ₂ facing each other, detector C composed of electrode C ₁ and electrode C ₂ is disposed a detection unit D constituted by the electrodes _{D 1} and the electrode _{D 2.} The intermediate plane 13 between the top surface 11 and the bottom surface 12 can be an inclined surface that is inclined by an angle θ with respect to the sensor surfaces 1a and 2a, which are the outer surfaces of the pressure plates 1 and 2, as shown. However, it may be a side surface perpendicular to the sensor surfaces 1a and 2a.
And between each electrode which the said pressure plates 1 and 2 oppose, in order to measure pressure distribution and frictional force distribution based on the electroconductivity of the pressure-sensitive conductive material 3, the arrangement | positioning aspect of each said electrode is used as the measurement means. A processing circuit corresponding to the above is connected.
[0012]
The sensor having the above configuration is configured to measure the pressure distribution and the frictional force distribution acting on the pressure plates 1 and 2 by the detection units A to D arranged in each part of the pressure-sensitive conductive material 3, Specifically, the pressure p acting on the sensor surfaces 1a and 2a in the direction perpendicular to the top and bottom surfaces 11, the bottom surface 12 and the intermediate plane (inclined surface) 13 between the concavities and convexities on the opposing surfaces of the pressure plates 1 and 2 is described. The distribution is measured, and the distribution of the frictional force t acting in the direction parallel to the sensor surfaces 1a and 2a is measured on the concave / convex intermediate plane (inclined surface or side surface).
[0013]
That is, when the pressure p and the frictional force t are applied in the vicinity of the detection unit, in the detection unit B and the detection unit D provided on the bottom surface and the top surface parallel to the sensor surfaces 1a and 2a, The force acting perpendicularly to each detection unit is only the force derived from the pressure p, and the value is the same in both detection units. Therefore, if the pressure is measured in the detection unit B and the detection unit D, the pressure p is directly applied. Can be sought.
[0014]
On the other hand, the force acting on the detection unit A and the detection unit C provided on the intermediate plane can be expressed as follows. That is, when the forces acting on the detection part A and the detection part C by the pressure p are Fp1 and Fp2, respectively, and l is the area of the detection parts A to D, their sizes are:
Fp1 = Fp2 = p · l
The direction is the same as the direction of the pressure p. Similarly, assuming that the forces acting on the detection unit A and the detection unit C by the frictional force t are Ft1 and Ft2, respectively, the magnitudes are Ft1 = Ft2 = t · l.
And the direction is the same as the direction of the frictional force t.
[0015]
Thus, in the detection unit A and the detection unit C, when the forces derived from the pressure p and acting in the direction perpendicular to the detection units are Np1 and Np2, respectively,
Np1 = Fp1 cos θ = p · l cos θ,
Np2 = Fp2cosθ = p · lcosθ
On the other hand, in the detection unit A and the detection unit C, when the forces acting in the vertical direction on the detection units derived from the frictional force t are Nt1 and Nt2, respectively,
Nt1 = Ft1sinθ = t · lsinθ,
Nt2 = −Ft2sinθ = −t · lsinθ
It is.
[0016]
Then, the forces in the direction perpendicular to the detection units acting in the detection unit A and the detection unit C are derived from the forces Np1 and Np2 acting on the part perpendicular to the pressure p and the frictional force t. Since it is the sum of forces Nt1 and Nt2 acting perpendicularly to the part, if N1 and N2 respectively,
N1 = Np1 + Nt1 = p · lcos θ + t · lsin θ,
N2 = Np2 + Nt2 = p · l cos θ−t · l sin θ
It is.
[0017]
Therefore, if the pressures acting on the detection unit A and the detection unit C are p1 and p2, respectively,
p1 = N1 / l = pcosθ + tsinθ,
p2 = N2 / l = pcosθ-tsinθ
It is.
[0018]
Then, if the pressure is measured at each of the detection part A and the detection part C, the above-mentioned p1 and p2 can be obtained. t can be obtained. That is,
t = (p1-p2) / 2sin θ
The frictional force t can be measured as
[0019]
At this time, in the formula of p2, when t sin θ becomes larger than p cos θ, this formula does not hold and p2 = 0. Since it does not become larger, it is possible to prevent tsin θ from becoming larger than p cos θ by appropriately selecting and designing θ according to the material of the surface to be measured.
[0020]
To elaborate further on this point, from the definition of the maximum static friction coefficient:
t ≦ μp
And applying this to the above equation for p2,
p2 ≧ pcos θ−μpsin θ = p (cos θ−μsin θ)
It is.
Moreover, the present invention is not intended for negative pressure, but for the case of p ≧ 0.
cos θ−μ sin θ ≧ 0
Therefore, p2 ≧ 0 is always established. Therefore, if θ is designed so that tan θ <1 / μ within the range of 0 <θ <90 °, the frictional force t is always obtained by the above-described method. Can be obtained.
[0021]
On the other hand, in the case of θ = 90 °, the detection unit A and the detection unit C are installed on the uneven surface of the opposing surface of the pressure plate, and the influence of the pressure p does not appear on these detection units, and the frictional force Since the frictional force t directly acts only on the detection unit in the direction opposite to t, that is, in the case of FIG. 1, the detection unit A, it can be easily detected.
Note that the pressure p can be obtained by adding p1 and p2 and dividing by the constant 2 cos θ determined by the shape of the opposing surfaces of the pressure plates 1 and 2. That is,
p = (p1 + p2) / 2 cos θ
The pressure p can be measured as
Accordingly, in the range of 0 <θ <90 °, the pressure p can be obtained even if the detection unit B and the detection unit D are omitted. That is, the sensor surfaces 1a, The unevenness of the pressure plate facing surface can be formed only by the inclined surfaces fitted to each other without providing the bottom surface and the top surface parallel to 2a. In this case, when forming a two-dimensional planar sensor, for example, the concave and convex shapes of the opposing surfaces of the pressure plates 1 and 2 can be realized as shown in FIG.
[0022]
In forming a two-dimensional surface sensor, a third surface 14 parallel to the sensor surface is formed in the middle of the top surface 11 and the bottom surface 12 of the concavities and convexities of the opposing surfaces of the pressure plates 1 and 2 as shown in FIG. By providing, the uneven | corrugated shape of the opposing surface of a pair of pressure plate can be utilized effectively. That is, when the third surface 14 is not provided, an invalid space 25 in which a detection unit cannot be installed between the uneven top surface 21 and the bottom surface 22 of the pressure plate as shown in FIG. By providing the surface 14, this can be eliminated, and the detection unit can be installed in all parts of the pressure plate facing surface.
[0023]
In the above, the embodiment has been described in which each detection unit is configured by a pair of electrodes facing each other and a sheet-like pressure-sensitive conductive material, but instead of facing the pair of electrodes in the detection unit, As shown in FIG. 5, it is also possible to arrange the comb-shaped electrodes in the same plane. This will be explained in the case of the detection unit A in FIG. 1. The electrode A1 is eliminated, and the electrodes E1 and E2 and the pressure sensitive sensor are arranged in parallel at the same place instead of the electrode A2. The detection part A can be constituted by the conductive material 3.
[0024]
In addition, the pressure plates 1 and 2 and the pressure-sensitive conductive material 3 in the sensor can be flexible, but if the sensor does not need to be flexible, it is used in the first embodiment. Instead of the pair of electrodes and the sheet-like pressure-sensitive conductive material of each detection unit, a thin pressure detection element can be used (second embodiment).
[0025]
In the first and second embodiments, the instantaneous pressure distribution and frictional force distribution can be detected, but when the maximum values of the pressure distribution and the frictional force distribution in an arbitrary period are recorded. Is configured so that the entire sensor including the pressure plates 1 and 2 can be disassembled and assembled, and a pressure recording film is used instead of using the pair of electrodes and the sheet-like pressure-sensitive conductive material of the first embodiment. (Third embodiment).
This third embodiment makes it possible to use a planar pressure distribution and frictional force distribution measuring sensor as a recorder. In this case, it is necessary to replace the pressure recording film each time it is measured. However, since electrodes and wiring are not required, it can be easily used for applications that require measurement of only the maximum value while ignoring temporal changes. Is possible.
[0026]
【The invention's effect】
As described above, the pressure distribution and frictional force distribution measurement sensor of the present invention can be made of a material that has a relatively simple structure, can be easily downsized, and has flexibility as required. Therefore, the present invention can be applied to a case where one or both of the contact surfaces to be measured are flexible or fragile, for example, when a human operates an object. It is also possible to easily measure pressure distribution and frictional force distribution in such a narrow range.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view for explaining the measurement principle of the present invention.
FIG. 2 is a perspective view showing another example of the shape of the opposing surface of the pressure plate.
FIG. 3 is a perspective view showing a shape example in which a third surface is provided on the concavity and convexity of the opposing surface of the pressure plate.
FIG. 4 is a partial perspective view showing a state in which an invalid space in which a detection unit cannot be installed when a third surface is not provided in the middle of the unevenness of the opposing surface of the pressure plate.
FIG. 5 is a perspective view showing a configuration of a detection unit configured by arranging comb electrodes on the same plane.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 2 Pressure plate 1a, 2a Sensor surface 3 Pressure-sensitive conductive material 11, 21 Top surface 12, 22 Bottom surface 13 Intermediate plane 14 Third surface 25 Invalid space A1-D1, A2-D2 Electrode A-D Detection part p Pressure t Friction force

Claims (3)

A sensor for measuring a planar pressure distribution and a frictional force distribution,
A sheet-like sandwiched between a pair of pressure plates that have a large number of concavities and convexities that fit into each other and spread in a planar shape on the opposing surface, and the opposing surfaces have the same shape, and the opposing surfaces of those pressure plates A pressure-sensitive conductive material,
The concavities and convexities on the opposing surfaces of the pair of pressure plates are formed by inclined surfaces,
An electrode facing each of the inclined surfaces of the irregularities is arranged to constitute a detection unit,
A detection means for detecting the conductivity between the electrodes in each of the detection units is provided,
Based on the detected conductivity, the pressure distribution acting in the direction perpendicular to the sensor surface which is the outer surface of the pressure plate and the friction force distribution acting parallel to the sensor surface are measured, respectively. Sensor for distribution measurement. A sensor for measuring a planar pressure distribution and a frictional force distribution,
A thin pressure sandwiched between opposing surfaces of a pair of pressure plates that have a large number of concavities and convexities that extend in a planar shape and that fit into each other on the opposing surface, and the opposing surfaces have the same shape. A detection unit configured by a detection element sheet,
The concavities and convexities on the opposing surfaces of the pair of pressure plates are formed by inclined surfaces,
A detection means for detecting the pressure in each of the detection units is provided,
A pressure distribution and a friction force distribution characterized by measuring a pressure distribution acting in a direction perpendicular to the sensor surface, which is the outer surface of the pressure plate, and a friction force distribution acting parallel to the sensor surface based on the detected pressure, respectively. Sensor for measurement. A sensor for measuring a planar pressure distribution and a frictional force distribution,
A pair of pressure plates that have a large number of concavities and convexities that extend in a planar shape and are fitted to each other on the opposing surface, and the pressure distribution that is sandwiched between the opposing surfaces of the pressure plates, the opposing surfaces having the same shape And a detection unit constituted by a recording film,
The concavities and convexities on the opposing surfaces of the pair of pressure plates are formed by inclined surfaces,
Based on the recording of the pressure distribution recording film, a pressure distribution acting in a direction perpendicular to a sensor surface which is an outer surface of the pressure plate and a friction force distribution acting in parallel with the sensor surface are respectively measured. And a sensor for measuring frictional force distribution.

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