JP2003098022A - Pressure distribution and frictional force distribution measuring sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure distribution and frictional force distribution measuring sensor having a comparatively simple structure, capable of being constituted from a material having flexibility if necessary. SOLUTION: This sensor is equipped with a pair of platens 1, 2 having facing surfaces having the same shape and many irregularities having flatly-spread shapes to be interfitted mutually, and a sheet pressure-sensitive conductive raw material 3 sandwiched between the facing surfaces of the platens. Facing electrodes A1 , C1 , A2 , C2 are disposed respectively on the inclined faces the irregularities on the facing surfaces of the platens, to thereby constitute a detection part, and a processing circuit for detecting conductivity between the electrodes at each detection part is provided. The pressure distribution working in the vertical direction on the sensor surface which is the outside surface of the platen and the frictional force distribution working in parallel with the sensor surface can be measured respectively based on the detected conductivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for measuring surface pressure distribution and frictional force distribution.

[0002]

2. Description of the Related Art Conventionally, as a planar pressure distribution measuring method, a required number of load cells are arranged on a measuring surface and the output thereof is appropriately amplified by an amplifier for measurement, or the present inventors have already patented the method. As disclosed in Japanese Patent No. 2034846 (Patent Document 1), pressure-sensitive elements formed of planar pressure-sensitive conductive rubber are arranged in a matrix, and required scanning circuits, switching circuits, signal processing circuits, etc. A method of measuring by combining is known. In addition, the present inventors have already issued Japanese Patent No. 2053811 (Patent Document 2).
As is clear from the above, there is also known a method of measuring the operating force distribution of the human hand by using the flexibility of the material in the latter method and configuring the detecting section in a shape similar to a glove. There is.

On the other hand, as a method of measuring the frictional force, a method using a three-component force meter using a load cell or the like is generally popular, and the present inventors have already disclosed the patent No. 1646028.
As disclosed in Japanese Patent Application Laid-Open No. 2004-242242 (Patent Document 3), the friction coefficient is detected by measuring the shift of the position of the center of gravity of the acting force with a pair of surface pressure sensors that are opposed to each other via an elastic spacer. A method is known in which a frictional force is measured by multiplying a surface pressure that is separately measured as appropriate by the friction coefficient. In particular, if a large number of the above-mentioned three-component force sensors are arranged, it is possible in some cases to measure the pressure distribution and the frictional force distribution at the same time. When one or both of the contact surfaces to be measured has flexibility or is vulnerable, such as when operating a , I could not respond.

[Patent Document 1] Japanese Patent Publication No. 7-58223

[Patent Document 2] Japanese Examined Patent Publication No. 7-86439

[Patent Document 3] Japanese Patent Publication No. 3-47699

[0004]

The problems to be solved by the present invention are as follows.
In view of the above circumstances, it is an object of the present invention to provide a sensor for measuring pressure distribution and frictional force distribution, which has a relatively simple structure and can be made of a material having flexibility as necessary.

[0005]

A sensor for measuring pressure distribution and frictional force distribution according to the present invention for solving the above-mentioned problems includes a pair of pressure plates having a large number of concavo-convex portions having mutually fitting shapes on opposite surfaces. , A sheet-shaped pressure-sensitive conductive material sandwiched between the facing surfaces of the pressure plate, and the electrodes facing the unevenness of the facing surface of the pressure plate, for example, the top surface, the bottom surface and an intermediate plane between them. The detectors are provided to constitute the detectors, and the detectors for detecting the conductivity between the electrodes of the detectors are provided. Based on the detected conductivity, the detectors act in the direction perpendicular to the outer surface of the pressure plate. It is characterized in that the pressure distribution and the frictional force distribution acting in parallel with the sensor surface can be measured.

Further, in the sensor according to the present invention, instead of the sheet-shaped pressure-sensitive conductive material and the electrode in the sensor having the above structure, a thin pressure detecting element is sandwiched between the opposed surfaces of the pressure plate at the position where the electrode is arranged. It is characterized in that the pressure acting on each part of the opposing surfaces of the pair of pressure plates can be measured by the pressing. That is, the above-mentioned sensor according to the present invention includes a pair of pressure plates having a large number of concavities and convexities of mutually fitting shapes on the opposite surfaces, and between the concavities and convexities of the confronting surfaces of these pressure plates, for example, between the top surface, the bottom surface and their intermediate planes. And a detection unit composed of a thin pressure detection element sandwiched between
A detection unit for detecting the output of the pressure detection element in each of the detection units is provided, and based on the detected pressure, a pressure distribution that acts in a direction perpendicular to the sensor surface that is the outer surface of the pressure plate, and acts in parallel with the sensor surface. It is characterized in that the frictional force distribution can be measured.

Further, in the sensor of the present invention, instead of the pressure-sensitive conductive material and the electrode in the sensor having the above structure, a pressure distribution is provided between a pair of pressure plates having a large number of concavities and convexities that are fitted to each other on opposite surfaces. The recording film is sandwiched, and the above-mentioned planar pressure distribution and frictional force distribution can be measured based on the recording of the pressure distribution recording film. That is, the sensor of the present invention, a pair of pressure plates having a large number of concavities and convexities of mutually fitting shapes on the opposing surfaces,
A pressure distribution recording film sandwiched between the opposing surfaces of the pressure plate and a detection unit, and based on the recording of the pressure distribution recording film, in the direction perpendicular to the sensor surface which is the outer surface of the pressure plate. The feature is that the acting pressure distribution and the frictional force distribution acting in parallel with the sensor surface can be measured.

In the sensor having the above structure, for example, the bottom surface and the top surface parallel to the sensor surface are not provided on the concavo-convex surface of the pressure plate, and the concavo-convex surface can be formed only by the slanting surfaces which are fitted to each other. A third surface parallel to the sensor surface can be provided in the middle of the unevenness of the facing surface of the pressure plate.

According to the sensor for measuring the planar pressure distribution and the frictional force distribution having the above-mentioned structure, the sensor is mounted on the working surface of the working machine or the human body surface, and the electrodes are arranged in the manner. By connecting the corresponding processing circuit, it is possible to simultaneously measure the pressure distribution and the frictional force distribution between the object in contact with the working surface or the body surface. When the pressure distribution recording film is used, the sensor is similarly attached to the working surface of the working machine or the human body surface, the pressure recording film is taken out after the work, and the recorded pressure record is appropriately analyzed. This makes it possible to measure the maximum pressure distribution and the maximum frictional force distribution between the working surface or the body surface and the contacting object.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a 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, and the sensor is represented as a one-dimensional one in FIG. It is composed of

The sensors shown in FIG. 1 are mutually fitted on opposite surfaces.
A pair of pressure plates 1 and 2 having a number of irregularities
It was sandwiched between the facing surfaces of these pressure plates 1 and 2 at almost constant intervals.
And a pressure sensitive conductive material 3 in the form of a sheet,
Of the concavo-convex surface of the opposite surface of the, the bottom surface 12 and between them
Opposed to each other with the pressure-sensitive conductive material 3 interposed therebetween on the intermediate plane 13.
Electrode A₁And electrode A_TwoA detection unit A composed of
Similarly, the opposite electrode B ₁And electrode B_TwoThe inspection consisting of
Output B, electrode C₁And electrode C_TwoDetection unit composed of
C, electrode D₁And electrode D_TwoThe detection unit D
I have set up. Intermediate plane between the top surface 11 and the bottom surface 12
As shown in FIG. 13, reference numeral 13 is a section which is an outer surface of the pressure plates 1 and 2.
An inclined surface inclined by an angle θ with respect to the sensor surfaces 1a and 2a.
Although it can be done,
It can also be on the side. Then, the pair of the pressure plates 1 and 2
The space between the facing electrodes is based on the conductivity of the pressure-sensitive conductive material 3.
To measure pressure distribution and frictional force distribution.
As a means, a processing circuit corresponding to the arrangement of the above electrodes is connected.
Will be continued.

In the sensor having the above-mentioned structure, the pressure plate 1 is provided by the detecting portions A to D arranged on the respective portions of the pressure-sensitive conductive material 3.
The pressure distribution and the friction distribution acting on 2 are measured, and more specifically, the uneven top surface 11, bottom surface 12 and the intermediate plane between them on the facing surfaces of the pressure plates 1 and 2 are measured. On the (slope) 13, the sensor surface 1a
The distribution of the pressure p acting in the direction perpendicular to 2a is measured, and the sensor surface 1 is measured on the intermediate plane (slope or side) of the unevenness.
The distribution of the frictional force t acting in the direction parallel to a and 2a is measured.

That is, when the pressure per unit area p and the frictional force t are acting in the vicinity of the detecting portion, the detecting portion B and the detecting portion provided on the bottom surface and the top surface parallel to the sensor surfaces 1a and 2a. In D, the force acting vertically on each detection unit is only the force derived from the pressure p, and the values are the same in both detection units. Therefore, if the pressure is measured in the detection unit B and the detection unit D, p can be obtained directly.

On the other hand, the force acting on the detecting portion A and the detecting portion C provided on the intermediate plane can be expressed as follows. That is, assuming that 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. And its direction is the same as the direction of pressure p. Similarly, if the forces acting on the detection unit A and the detection unit C by the friction force t are Ft1 and Ft2, respectively, the magnitude is Ft1 = Ft2 = t · l, and the direction is the direction of the friction force t. Is the same as

Thus, in the detecting section A and the detecting section C,
Letting Np1 and Np2 be the forces originating in the pressure p and acting in the direction perpendicular to these detection parts, respectively, Np1 = Fp1cosθ = p · lcosθ, Np2 = Fp2cosθ = p · lcosθ, while the detection parts A and In the detection unit C, if the forces derived from the frictional force t and acting in the vertical direction on these detection units are Nt1 and Nt2, respectively, then Nt1 = Ft1sinθ = t · lsinθ and Nt2 = −Ft2sinθ = −t · lsinθ .

The forces acting in the detectors A and C in the direction perpendicular to the detectors are derived from the forces pp1 and Np2 acting perpendicularly on the parts due to the pressure p and the frictional force t. Then, the force Nt1, which acts vertically on the relevant portion,
Since it is the sum of Nt2 and N1 and N2, respectively, N1 = Np1 + Nt1 = p · lcosθ + t · lsin
θ, N2 = Np2 + Nt2 = p · lcos θ−t · lsin
θ.

Therefore, assuming that the pressures acting on the detecting portion A and the detecting portion C are p1 and p2, respectively, p1 = N1 / l = pcosθ + tsinθ and p2 = N2 / l = pcosθ-tsinθ.

Then, if the pressures are respectively measured at the detecting portion A and the detecting portion C, the above p1 and p2 can be obtained, and if p1 and p2 are subtracted and divided by a constant 2 sin θ determined by the shape of the facing surface of the pressure plate. , The friction force t can be obtained. That is, the frictional force t can be measured as t = (p1-p2) / 2sinθ.

At this time, in the above equation of p2, tsi
When nθ becomes larger than pcosθ, this formula does not hold and p2 = 0, but since t is a frictional force, it does not become larger than the value obtained by multiplying the pressure p by the maximum static friction coefficient μ. It is possible to prevent tsinθ from becoming larger than pcosθ by appropriately selecting and designing θ according to the material of the target surface and the like.

To further elaborate this point, from the definition of the maximum static friction coefficient, t ≦ μp, and when this is applied to the above equation of p2, p2 ≧ pcos θ−μpsin θ = p (cos θ−μs
in θ). Moreover, since the present invention is not intended for negative pressure but for p ≧ 0, if cos θ−μsin θ ≧ 0, then p2 ≧ 0 will always hold, and therefore 0 < By designing θ so that tan θ <1 / μ in the range of θ <90 °, the frictional force t can always be obtained by the above method.

On the other hand, in the case of θ = 90 °, the detecting portions A and C are installed on the uneven side surfaces of the facing surface of the pressure plate, and the influence of the pressure p does not appear on these detecting portions. ,
Since the frictional force t directly acts only on the detection unit in the direction opposite to the frictional force t, that is, the detection unit A in the case of FIG. 1, it can be easily detected. Note that p1
And p2 are added together and divided by a constant 2cos θ determined by the shapes of the facing surfaces of the pressure plates 1 and 2, the pressure p can be obtained. That is, the pressure p can be measured as p = (p1 + p2) / 2cos θ. Therefore, 0
In the range of <θ <90 °, it is possible to obtain the pressure p even if the detectors B and D are omitted, that is, the unevenness of the facing surfaces of the pressure plates 1 and 2 is parallel to the sensor surfaces 1a and 2a. It is possible to form the unevenness of the pressure plate facing surface only by the inclined surfaces which are fitted to each other without providing the bottom surface and the top surface. In this case, in constructing the two-dimensional planar sensor, it can be realized by, for example, forming the concavo-convex shape of the facing surfaces of the pressure plates 1 and 2 into the shape shown in FIG.

In constructing a two-dimensional planar sensor, as shown in FIG. 3, a third surface parallel to the sensor surface is provided in the middle of the top surface 11 and the bottom surface 12 of the unevenness of the opposing surfaces of the pressure plates 1 and 2. By providing the surface 14, the concavo-convex shape of the opposing surfaces of the pair of pressure plates can be effectively used. That is, when the third surface 14 is not provided, as shown in FIG. 4, an ineffective space 25 in which a detection unit cannot be installed is generated between the top surface 21 and the bottom surface 22 of the unevenness of the pressure plate. Providing the surface 14 makes it possible to eliminate this and to install the detection unit on all parts of the surface facing the pressure plate.

In the above, the embodiments in which the respective detecting portions are composed of a pair of electrodes facing each other and a sheet-shaped pressure-sensitive conductive material have been described. Alternatively, the comb-shaped electrodes may be juxtaposed in the same plane as shown in FIG. This will be described in the case of the detection unit A of FIG.
By eliminating the electrode A1 and arranging the comb-shaped electrodes E1 and E2 in place at the same place in place of the electrode A2, the electrodes E1 and E2
The pressure-sensitive conductive material 3 and the detection unit A can be configured.

The pressure plates 1 and 2 and the pressure-sensitive conductive material 3 in the sensor can be made flexible, but when it is not necessary to make the sensor flexible, the first embodiment described above is used. It is also possible to use a thin pressure detecting element instead of the pair of electrodes of each detecting section and the sheet-shaped pressure-sensitive conductive material used in (2nd Example).

In the first and second embodiments described above, the pressure distribution and the frictional force distribution can be detected every moment, but the maximum values of the pressure distribution and the frictional force distribution in an arbitrary period are recorded. In this case, instead of using the pair of electrodes and the sheet-shaped pressure-sensitive conductive material of the first embodiment so that the entire sensor including the pressure plates 1 and 2 can be disassembled and assembled, a pressure recording film is used. It can be used (third embodiment). According to the third embodiment, it becomes possible to use the planar pressure distribution and frictional force distribution measuring sensor also as a recorder. In this case, the pressure recording film needs to be replaced after each measurement, but since it does not require electrodes and wiring, it can be easily used for applications requiring only the maximum value while ignoring changes over time. It is possible.

[0026]

As described above, the sensor for measuring pressure distribution and frictional force distribution of the present invention is composed of a material having a relatively simple structure, easy miniaturization, and flexibility if necessary. It is possible. Therefore, the present invention can be applied to the case where one or both of the contact surfaces to be measured has flexibility or is vulnerable, for example, when a person operates an object. It is also possible to easily measure the pressure distribution and the frictional force distribution in such a narrow range.

[Brief description of 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 facing surface of the pressure plate.

FIG. 3 is a perspective view showing an example of a shape in which a third surface is provided on the concavities and convexities on the opposite 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 occurs when a third surface is not provided in the middle of the unevenness of the facing surface of the pressure plate.

FIG. 5 is a perspective view showing a configuration of a detection unit configured by arranging comb electrodes in the same plane side by side.

[Explanation of symbols]

1, 2 pressure plate 1a, 2a Sensor surface 3 Pressure-sensitive conductive material 11,21 Top surface 12,22 Bottom 13 Midplane 14 Third side 25 Invalid space A1-D1, A2-D2 electrodes A to D detector p pressure t friction force

Claims (3)

[Claims] 1. A sensor for measuring a planar pressure distribution and a frictional force distribution, which has a large number of irregularities in a mutually extending shape that are fitted to each other, the opposing surface It has a pair of pressure plates having the same shape and a sheet-shaped pressure-sensitive conductive material sandwiched between the opposing surfaces of the pressure plates, and the concavo-convex portions of the opposing surfaces of the pair of pressure plates are formed by inclined surfaces. Assuming that the detecting portions are formed by disposing electrodes facing each other on the inclined surfaces of the irregularities, a detecting means for detecting the conductivity between the electrodes in each of the detecting portions is provided, and based on the detected conductivity, A pressure distribution and frictional force distribution measuring sensor, which measures a pressure distribution acting in a direction perpendicular to a sensor surface which is an outer surface of a pressure plate and a frictional force distribution acting in parallel with the sensor surface. 2. A sensor for measuring a planar pressure distribution and a frictional force distribution, which has a large number of irregularities in a shape that fit in each other and spread in a planar shape. The pressure plate has a pair of pressure plates having the same shape and a detection unit constituted by a thin pressure detection element sheet sandwiched between the pressure plates facing each other. And a pressure distribution that acts on the sensor surface, which is the outer surface of the pressure plate, in the vertical direction based on the detected pressure. A sensor for measuring a pressure distribution and a frictional force distribution, which is characterized by measuring a frictional force distribution acting on each. 3. A sensor for measuring a planar pressure distribution and a frictional force distribution, which has a large number of irregularities in a mutually-fitting shape spread in a planar shape, the opposing surface being It has a pair of pressure plates having the same shape, and a detection unit constituted by a pressure distribution recording film sandwiched between the opposing surfaces of the pressure plates, and the unevenness of the opposing surfaces of the pair of pressure plates is formed by the inclined surface. 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 are measured respectively. A sensor for measuring pressure distribution and frictional force distribution characterized by: