JP4247474B2 - Softness measuring method and softness measuring device - Google Patents

Description

  The present invention provides soft objects such as jelly, konjac, agar, tofu, meat, fish, sol / gel, etc., elastic bodies such as tennis balls and rubber materials, biological parts such as organs, organs, and eyeballs, The present invention relates to a method and an apparatus for measuring the softness of an object.

In the conventional method for measuring the hardness of an object, if it is rubber, the push needle is pressed with a predetermined load, and the penetration depth is determined. In general, there is a method of measuring hardness by pressing an indenter against the surface of an object to be measured, such as a Brinell hardness test.
Further, in the method of measuring intraocular pressure described in Patent Document 1, when a fluid is sprayed on the cornea and the cornea becomes flat pressure, that is, until the pressure or flat pressure when a part of the cornea becomes flat is reached. The intraocular pressure is measured according to the time.
Japanese Patent Application Laid-Open No. 07-171111

In the above contact-type measurement method, measurement is performed by contacting a hard object. Therefore, assuming a soft object to be measured such as pudding, the object to be measured is not only likely to be damaged or damaged, but also to prevent infection. There is a problem in terms of hygiene.
In addition, since the measurement method of Patent Document 1 employs the applanation method, spray is performed while gradually changing the fluid injection pressure, and the injection pressure is controlled so that the cornea is flattened, that is, flat from the convex shape. There is a need to. In other words, it is necessary to measure the instantaneous pressure that becomes a flat pressure, and fluid injection pressure control is troublesome. Further, it can be applied only to a convex surface such as an eyeball.
This invention pays attention to the above points, and makes it a subject to measure the softness of the to-be-measured object even if the surface shape of the to-be-measured object is not convex.

In order to solve the above-mentioned problem, Claim 1 of the present invention is a method for measuring the softness of an object, wherein the fluid is sprayed toward the surface of the object to be measured with a constant jet pressure, and the surface of the object to be measured is measured. And the softness of the object to be measured is determined by the surface area of the recess formed in a state where the fluid is ejected at the constant spray pressure and the load applied to the surface of the object by the ejected fluid. Determine and measure the two-dimensional cross-sectional shape of the dent deformed by the jetted fluid in a non-contact manner, and approximate the shape of the dent to a part of a spherical surface based on the measured two-dimensional cross-sectional shape. It is characterized by calculating | requiring.
Next, the invention described in claim 2 is a fluid ejecting apparatus that injects a fluid at a constant injection pressure toward the surface of the object to be measured so as to face the surface of the object to be measured, and an injection at the constant injection pressure. A shape detecting device for detecting a two-dimensional cross-sectional shape of the depression formed on the surface by the applied fluid during the injection at the constant injection pressure and in a non-contact manner, and a load on the surface of the object to be measured by the injected fluid And a calculation unit for calculating a value serving as a softness index from the surface area of the depression obtained from the two-dimensional shape of the depression and the depression , by approximating the depression shape to a part of a spherical surface. The softness measuring device is characterized in that the surface area is obtained.

Next, the invention described in claim 3 is formed on the surface by the fluid ejecting apparatus that ejects the fluid toward the surface by disposing the nozzle facing the surface of the object to be measured, and the ejected fluid. A shape detection device that detects the recess shape in a non-contact manner, a load applied to the surface of the object to be measured by the jetted fluid, and a value serving as an index of softness from the surface area of the recess obtained from the recess shape and a calculator for, the nozzle openings are circular in shape, and toward the workpiece straight ejecting a fluid, the shape detecting apparatus, a laser beam of a line beam shape to the surface of the object to be measured , And the reflected light is received by the two-dimensional image capturing means, thereby detecting the two-dimensional shape of the cross section of the depression, and the arithmetic unit approximates the depression to a part of a spherical surface, thereby detecting a shape. Secondary section detected by It is characterized in that determining the surface area of the recess diameter of the depth and depression of the depression is determined from the shape.

According to the present invention, since the measurement is performed without contact, it is hygienic, and measurement can be performed if a slight depression can be formed on the surface. Moreover, since it is possible to measure with the fluid pressure of the injection constant, the adjustment of the injection pressure is easy and the injection pressure is stabilized, leading to improvement in measurement accuracy.
Although measured by blowing fluid, since it is sufficient formation recess of small depth on the surface as described above, because it can small fence set the soft ones as injection pressure, even soft things like tofu Injury or damage can be suppressed.

Next, an embodiment based on the present invention will be described with reference to the drawings.
First, the principle of softness measurement according to this embodiment will be described with reference to FIG. In addition, in order to make it easy to understand in the hollow 11 shown in FIG. 1, the depth is illustrated to be large.
A fluid such as air is blown straight from the nozzle 6 having an opening area A toward the surface of the object 10 to be measured at a constant flow velocity V, and the sprayed fluid G hits the object 10 to be measured per unit time. The mass M loaded on the measurement object 10 is ρ · A · V. ρ represents the density of the fluid.

Further, when the opening of the nozzle 6 to the diameter and d is ^{circular, A = π · d 2/} 4 , and the injection force F is a load object to be measured 10 is subjected is expressed by the following equation.
F = MV = ρ · A · V 2 = ρ · π 2 · V 2/4 ··· (1)
On the other hand, the depression 11 formed in the DUT 10 due to the collision of the jet fluid can be approximated to a part of a spherical surface if the depression 11 has a small depth. Therefore, the surface area S of the depression 11 is geometrically as follows. It is expressed by a formula.
S = π · d1 · h (2)
here,
d1: Diameter of the depression 11 h: Depth of the depression 11 h = (1- (1-d1 ² / D ² ) ⁻² ) D / 2
(However, the radius of curvature of the sphere including the depression 11 is D / 2.)
It is.

Therefore, when pressure is adopted as the softness index and Hb is adopted, the Hb can be obtained by the following equation.
Hb = F / S = (ρ · d ² · V ² ) / (4 · d1 · h) (3)
As can be seen from the equation (3), Hb, which is an index of softness, can be calculated if the injection force F, the depth h of the depression 11 and the diameter d1 are obtained.

Next, the softness measuring apparatus based on this invention is demonstrated, referring drawings.
FIG. 1 is a schematic diagram of an apparatus configuration according to the present embodiment.
The apparatus according to the present embodiment includes a fluid ejection device 1, a shape detection device 2, and a calculation unit 3.
The fluid ejection device 2 includes a compressor 4, a regulator 5, and an ejection nozzle 6. The compressor 4 pumps compressed air to the regulator 5 according to a command from the calculation unit 3. The regulator 5 adjusts the compressed air to a predetermined pressure and then injects straightly from the ejection nozzle 6 toward the surface 10 a of the object to be measured 10.

As shown in FIG. 3, the shape detection device 2 converts the laser light L into a wide line beam L <b> 1 by the projection lens 21, and irradiates the surface of the measurement object 10 that is depressed by the jetting fluid. The reflected light L2 is received by the two-dimensional CCD 23, which is a two-dimensional image pickup device, through the light receiving lens 22, so that the two-dimensional cross-sectional shape of the depression 11 is picked up in a short time, that is, at a time. The acquired information of the two-dimensional cross section is output to the calculation unit 3.
The computing unit 3 obtains the diameter d1 and the depth h of the depression 11 by approximating the depression 11 to a part of a spherical surface based on the two-dimensional cross-sectional shape information (profile information) input from the shape detection device 2. . And the softness | index Hb is calculated | required based on a following formula using the preset injection force F, and it outputs to a display part and database which are not shown in figure.
Hb = F / S = F / (4 · d1 · h) (4)

Next, an example of how to use the softness measuring device will be described with reference to FIG.
First, the regulator 5 is adjusted so that a slight depression 11 can be formed on the surface of the object 10 to be measured, and the electronic balance is used for the electronic balance. The jet force F is actually measured by arranging the nozzle 6 at a position separated by a distance and ejecting the nozzle 6, and the jet force F is set in the calculation unit 3.
The injection force F may be calculated by a theoretical formula consisting of the above formula (1), but the actual injection force F and the theoretical value obtained from the theoretical formula depending on the facing distance from the object to be measured 10 and the like. Since there is a predetermined error, in this embodiment, the injection force F is obtained in advance as described above. Of course, the injection force F may be obtained by multiplying the above theoretical formula by a correction coefficient. Note that the actual injection force F is larger than the theoretical value.

Then, the surface of the object to be measured 10 and the nozzle 6 are made to face each other by the predetermined distance.
Further, the position adjustment device 7 performs position adjustment so that the line-shaped laser beam L1 passes through the surface position of the object to be measured 10 with which the axis of the nozzle 6 is opposed.
When the calculation unit 3 is operated in this state, the calculation unit 3 outputs an operation command to the compressor 4. Then, a fluid having a predetermined pressure is ejected from the nozzle 6 toward the surface of the object to be measured 10 and is caused to collide with the surface to form the recess 11. In synchronization, the two-dimensional cross-sectional shape of the dent 11 of the DUT 10 deformed by the jetted fluid G is measured by the shape detection device 2, and the calculation unit 3 determines the dent 11 from the two-dimensional information of the shape of the dent 11. The surface area is calculated, and the softness index Hb is calculated based on the equation (4).

Here, the injection from the nozzle 6 may be a single shot (one-shot) or may be continuously sprayed. In short, when the shape detection device 2 detects the shape of the recess 11, it may be sprayed with the same injection pressure.
The softness measuring apparatus having the above configuration measures the softness in a non-contact manner. Therefore, when measuring foods such as jelly and organs such as the eyeball, there is no risk of infection and it is hygienic and safe.
Moreover, the spray pressure is set to such an extent that the recess 11 is slightly formed, and the fluid is merely sprayed. Therefore, even a soft substance such as jelly may be set to a small injection pressure corresponding to the softness, and thus it is possible to prevent the substance from being wrinkled or damaged.

Further, when the shape can be detected in a short time as in the above embodiment, the fluid may be ejected only once. Further, even when the fluid is continuously ejected, the fluid pressure to be ejected may be fixed at a constant value, so that the fluid can be ejected stably and can be measured easily and accurately. .
Furthermore, the surface of the object to be measured can be flat, convex, concave, or slightly uneven, so the surface can measure the softness of various substances. Can do.

Here, in the said embodiment, although air is illustrated as a fluid, other gases, such as nitrogen, and liquids, such as water, may be sufficient. What is necessary is just to select the optimal fluid by the property of the to-be-measured object 10 made into object.
Moreover, although the said shape detection apparatus 2 demonstrated with the apparatus which can detect a cross-sectional 2D shape at once, it detects the information of a cross-sectional 2D shape continuously or intermittently along the straight line which passes along the center of the position to be depressed. Such a shape detection device 2 may be adopted. In this case, the control may be performed so that the fluid is ejected continuously or intermittently according to the measurement. Even in this case, the injection pressure may be set constant.

Moreover, in the said embodiment, although the shape of the hollow 11 is approximated to a part of spherical surface and the surface area of the hollow 11 is calculated | required, you may calculate the surface area of the hollow 11 by ellipse approximation etc. Or you may make it calculate the surface area of the hollow 11 by non-contact by another method.
In the present embodiment, the softness index Hb is indicated by pressure, but the present invention is not limited to this. For example, in the case of sequentially measuring the same kind of substances that are sequentially sent, a ratio with a reference pressure value may be used as a softness index, and a dimensionless number may be used.

It is a figure explaining the principle of this invention. It is a schematic diagram which shows the apparatus structure which concerns on embodiment based on this invention. It is a schematic diagram explaining the shape detection apparatus 2 which concerns on embodiment based on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluid injection apparatus 2 Shape detection apparatus 3 Computation part 4 Compressor 5 Regulator 6 Nozzle 10 Measured object 11 Indentation Hb Softness index h Indentation depth d1 Indentation diameter D / 2 Radius curvature radius F of injection sphere

Claims (3)

A method for measuring the softness of an object, in which a fluid is blown toward the surface of the object to be measured at a constant spray pressure to dent the surface of the object to be measured, and the fluid is sprayed at the constant spray pressure. The softness of the object to be measured is determined by the surface area of the depression that is being applied and the load applied to the surface of the object to be measured by the jetted fluid,
Measuring the two-dimensional shape of the depression deformed by the jetted fluid in a non-contact manner, and determining the surface area of the depression by approximating the shape of the depression to a part of a spherical surface based on the measured two-dimensional shape of the depression. Softness measuring method characterized by A fluid ejecting apparatus which ejects fluid at a constant injection pressure toward the surface disposed opposite the nozzle surface of the object, the recesses are formed on the surface by the fluid injected in the constant injection pressure A shape detection device that detects a two-dimensional cross section during non-contacting with the above-described constant injection pressure, a load applied to the surface of the object to be measured by the injected fluid, and a two-dimensional cross-sectional shape of the depression A calculation unit that calculates a value that is an index of softness from the surface area of the depression obtained from
A softness measuring apparatus characterized by obtaining the surface area of the depression by approximating the depression shape to a part of a spherical surface. A fluid ejecting device that ejects fluid toward the surface of the object to be measured while facing the nozzle, and a shape detection device that detects a hollow shape formed on the surface by the ejected fluid in a non-contact manner. A calculation unit that calculates a value serving as an index of softness from a load applied to the surface of the object to be measured by the jetted fluid and a surface area of the depression obtained from the depression shape;
The nozzle has a circular opening, and injects a fluid straight toward the object to be measured. The shape detector irradiates the surface of the object to be measured with a line beam of laser light, and the reflected light. Is received by the two-dimensional image capturing means to detect the two-dimensional shape of the cross section of the depression,
The arithmetic unit approximates the depression to a part of a spherical surface, and obtains the surface area of the depression from the depth of the depression and the diameter of the depression obtained from the two-dimensional cross-sectional shape detected by the shape detection device. Softness measuring device.

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