JPS6320136B2 - - Google Patents

Description

Detailed Description of the Invention The present invention applies pressure to the surface of a human body, folding mattress, futon, aircraft body, or other object with a force that rapidly increases or decreases, and adjusts the depth of the depression on the object surface corresponding to each force. -Relates to a device for obtaining strain diagrams. Examples will be explained below.

Figures 1 and 2 show the moving part of the pressure-strain diagram recording apparatus according to the present invention, and 1 is a cylindrical container made of plastic with closed upper and lower ends, and the vertical length of the interior thereof is 20 cm. Reference numeral 2 denotes a high frequency transformer placed over the lower half of the outer surface of the container 1, which incorporates a high frequency coil 2a shown in Figure 3 wound over a vertical length of 10 cm, and a high frequency coil 2b wound overlappingly on the outside. ing. 3
is an iron cylindrical weight with an outer diameter slightly smaller than the inner diameter of container 1 and a vertical length of 10 cm. 4 is a disc-shaped electronic circuit box with a built-in battery attached to the bottom of the container 1. 5 is a small disk-shaped piezoelectric element made of barium titanate or the like attached to its lower surface. 6 is a protruding hard plastic contact attached to the bottom surface.

FIG. 3 is an electrical circuit diagram of this movable part, and the operation of the movable part will be explained below using other figures as well.

Grasp the top of the container 1 with your hands, shake it down perpendicularly to the horizontal surface of the human body or other object to be measured, press the contact against the surface, and quickly pull it up to complete one measurement. The time required for this is approximately 0.1s.

Now, the height of the surface of the object to be measured is set as a reference altitude of 0 cm, and the lower end of the contact 6 starts from a height of 5 cm above, takes 0.04 s to reach the object surface, and gradually decelerates to 0.01 s. If we indent the surface of the object to a depth of 2 cm, and then reverse the process and return to the original height, we can form a displacement curve corresponding to time, as shown in graph A in Figure 4. I'll end up drawing it.

If the initial height of the lower end of the weight 3 is 10 cm, the weight 3 will fall freely due to the acceleration of gravity G (980 cm/s↑2), and when the lower end of the contact touches the object surface, the height will be 10-1/2× It reaches a height of 980×0.04↑2=9.216 (cm), and when the bottom end of the contact leaves the object surface, it reaches a height of 10-1/2×980×0.06↑2=8.236 (cm). , the lower end of the container is at a height of 5
cm, and there is a gap of 3.236 cm, but soon the lower end of the weight collides with the lower end of the rising inner space, is pulled up, returns to its original height, and takes a displacement curve as shown in graph B in Figure 4.

Further, the distance between the lower end of the weight 3 and the lower end of the inner space, that is, the graph C is given by C=B-(A+5). (The distance between the lower end of the inner space and the lower end of the contact is 5 cm) When the movable lower end is 5 cm above the object, the iron weight 3 is in the high frequency transformer 2, the inductance of the coil 2a is large, and this coil and The resonant frequency of the parallel resonant circuit constituted by the capacitor 7 in the electronic circuit box 4 exhibits a minimum value. Due to the movement of the container 1, the weight 3 is relatively removed from the coil 2a, and while it returns, the resonant frequency increases and returns, and its change curve correlates with the graph C, as shown in the graph D in FIG.
becomes.

From the battery 8 in the box 4 through the coil 2b,
Since the collector circuit of the transistor 9 is energized and the terminal voltage of the coil 2a is applied to the base circuit of the transistor, an oscillation circuit is formed, and the output voltage of the transistor 9 is applied to the antenna 10 built in the box 4. It becomes a radio wave signal and is radiated into space.

This radio wave signal changes as shown in graph D, and becomes a frequency modulated representation of the relative displacement of the container 1 with respect to the weight 3. (Since the container 1 and the contact 6 move almost in parallel, it can also be said that this indicates the relative position of the contact 6 with respect to the weight 3.) The lower end of the contact 6 descends and stands on the object surface. Until then, acceleration due to speed increase is applied, inertia force is generated due to the weight of the contact and the piezoelectric element, the piezoelectric element 5 receives a force that bends in the vertical direction, and the element 5 generates an output voltage. However, the mass of both is small and the output voltage is also small.

After 0.04s, the lower end of the contact reaches the object surface, and 0.01s
During this period, the contact 6 presses the piezoelectric element 5 with a gradually increasing pressure, and during the next 0.01 s, the pressure gradually decreases.
Due to the deceleration just before the contact leaves the object and returns to its original height, inertia acts on the contact and the piezoelectric element, and the piezoelectric element receives a bending force.

The output voltage change curve of such piezoelectric element 5 is as shown in graph E in FIG.

This voltage is frequency-modulated by an FM modulator 11 inside the box 4, and is radiated to the outside space from an antenna 12 built into the box 4 as a radio wave in a frequency band different from that emitted from the antenna 10. The frequency change curve of the radio wave is as shown in graph F in FIG.

The two types of radio waves radiated from the active part in this way are received by the box-shaped fixed part 13 shown in FIG. 8 placed nearby, and a graph is formed as a measurement result. In the figure, 14 and 15 are receiving antennas.

FIG. 9 is a block diagram of the electric circuit inside the fixing part 13, and the function of the fixing part will be explained below using this diagram.

Contactor 6 for weight 3 coming out of antenna 10
A radio wave signal indicating the relative position of 2 enters the antenna 14, is detected by the FM detector 16, passes through the built-in coupling capacitor, produces an output voltage with the same waveform as graph C, and is converted to 100KHz by the A-D converter 17. The signal is converted into a digital signal and recorded in the memory of the computer 18 at a sampling frequency of approximately 100 kHz.

Further, the signal radio wave of the piezoelectric element 5 output from the antenna 12 enters the antenna 15 and is detected by the FM detector 19, and the output voltage having the same waveform as graph E is output by the A-D converter 20 with the same frequency as the converter 17. The signal is converted into a digital signal and recorded in the memory of the computer 18. Note that when the output of the converter 17 remains at OV for a certain period of time, the computer 18 does not record the signal, but when it detects that it has risen from O, it starts recording and maintains the O level for a certain period of time. If this continues, recording will stop. Therefore, only the curved portion of graph C is recorded. In conjunction therewith, the output of the A/D converter 20 is recorded in a memory location of the computer 18 that is different from the portion containing the output of the converter 17.

Then, based on the output of the converter 17, that is, the graph C, the computer 18 calculates the displacement corresponding to time of the lower end of the container 1 and the contactor 6 linked thereto, that is, the height when the height at the start of descent is 0 cm. An operation is performed to obtain the change curve a.

At that time, a displacement curve b in which the height of the lower end at the start of free fall of the weight 3 is 0 cm is also used as a parameter.

The relational expression is C=b-a∴a=b-C.

Among these, C is the value sent to the fixed part as a radio wave signal, and b is b=-1/2×980×t
↑2 (where t is time s), computer 1
This is a value that can be calculated within 8.

Therefore, it is possible to find a. 1st
Figure 0 shows a graph showing the relationship between these three.

Then, the computer 18 detects the abrupt rising start point in the graph E of the output signal of the piezoelectric element 5,
In other words, the time when the contactor 6 contacts the object surface is
Detected as a part where the differential value (differential coefficient) increases rapidly,
Detecting the point at which the lower end of the contactor 6 is deeply embedded into the object as the point where the differential value becomes 0,
By plotting the value of a corresponding to each time between the two points as the X coordinate and the value of E as the Y coordinate, and printing it out with the printer 21 attached to the computer 18 (an XY plotter or the like may be used), the 11th The final measurement result as shown in graph G in the figure will be obtained.

By slowly moving the movable part, bringing it to the next measurement part, and performing the same operations as above, the following graph can be obtained.

In this way, graphs of many parts can be drawn in a short period of time.

Various design changes can be made to the above embodiment. The outline is described below.

The material, shape, structure, size, etc. of each part constituting the movable part can be arbitrarily selected. For example, the high frequency transformer 2 may be embedded within the wall of the container 1. The electronic circuit box 4 may be embedded in the bottom wall of the container 1 or mounted on the top wall, and the piezoelectric element 5 may be directly connected to the bottom surface of the container 1.

The piezoelectric element 5 includes not only a piezoelectric body but also a pressure-sensitive diode,
Strain gauges and others may also be used.

The container 1 may be attached to a drive device using an electric motor or air pressure, and the container 1 may be struck against an object to be measured and then pulled and released.

A flexible cord may be used to connect the antennas 10 and 14, as well as the output terminal of the piezoelectric element 5 and the input terminal of the A-D converter 20 in the fixed part.

A slide resistor is embedded in the inner surface of the container 1, its knob is connected to the weight 3, the slide resistor is driven by the inertia of the weight, the voltage change caused by the change in resistance is converted from analog to digital, and it is transmitted on radio waves. Good too.

The high frequency transformer 2 is omitted, a piezoelectric element for acceleration measurement is attached to the bottom of the inner space of the container 1, a weight 3 is attached on top of the piezoelectric element, and the voltage change component output of this piezoelectric element is taken out through a capacitor. A-D conversion is carried out at A-D, and then it is transmitted from the antenna 10 on a radio wave (PCM modulation), received by the antenna 14, passed through a demodulator, obtains a voltage with the same waveform as the output of the piezoelectric element, and converts that voltage into A-D. D converter 17
The above-mentioned graph a may be obtained by digitizing the data, integrating it in real time in the computer 18, converting it into velocity information, and further integrating and converting it into displacement information. (It is well known that double integration of acceleration information yields displacement information.) In this case, the output of the piezoelectric element passing through the capacitor is ) The element is stretched, producing a negative voltage output; during deceleration (positive acceleration) the element contracts, producing a positive voltage output; when increasing speed upward (positive acceleration) the element contracts, producing a positive voltage During deceleration (negative acceleration) the element is stretched, producing a negative voltage output,
In either direction, the element retains its original length during uniform motion (no acceleration) and provides zero voltage output.

The A-D converter 17 outputs acceleration digital information converted at a sampling frequency of about 100 KHz, and the computer 18 sequentially integrates (including addition and subtraction) the voltage values from 0s when the container 1 starts. That is, the velocity value corresponding to each time is obtained by integrating, and at the same time, this velocity information is integrated (integrated) from the start of the container 1, and the altitude corresponding to each time, that is, the graph which is displacement information is obtained. Find a.

A sensor other than the above-mentioned method that converts acceleration into voltage in real time may be attached to the container 1.

When measuring a side surface or an inclined surface of an object to be measured, the container 1 must be placed in a horizontal or inclined position.A piezoelectric element for measuring the inclination is attached to the top surface of the container 1, and a weight for measuring the inclination is placed on top of the piezoelectric element. If the container 1 is tilted from the vertical direction during crucifixion, the output of the piezoelectric element is made to decrease, and the output voltage is transmitted by radio waves and received by a dedicated antenna on the fixed part.
The computer 18 performs wave detection and A-D conversion.
Calculate the inclination angle from the voltage value in , find the long axis direction component of the container 1 of the acceleration of gravity applied to the weight 3, and b
The calculation formula for calculating a may be corrected, and the displacement of the weight 3 within the container 1 due to the fall in the longitudinal direction of the container 1 may be calculated, and a may be calculated.

In this case, the vertical length of the piezoelectric element and the weight are small. If the output of the piezoelectric element is 1 when the container 1 is oriented vertically before it starts moving toward the object to be measured, an output voltage proportional to the cosine of the inclination angle with respect to the vertical line is generated. Therefore, the computer 18 that received the signal is G (980 cm/s
You can calculate b by multiplying ↑2) by that value.
(Information during driving can also be used.) It is easy to change the graph format of the measurement results in various ways or to display them in a numerical table.

The material of the weight 3 may be replaced with helite or other materials.

Various other design changes are possible.

Note that when the object to be measured is a flexible and thick object, such as the abdomen of a human body or a thick rubber plate, the curve of the depth of the indentation versus time, graph a, becomes deeper, and the pressure curve obtained at the same time, graph E. Graph G of the pressure-strain diagram obtained from , has a gentle slope.

If the object to be measured is a strongly fixed thick steel plate, graph a will be an approximate straight line with a depth close to 0, and graph E will take a very short time to rise and will have a steep slope. Draw an approximate square wave.

However, even during this short period of time,
The lower end of the contactor 6 presses down on the target surface, and since the output voltage is gradually generated from the piezoelectric element 5, a pressure-strain diagram can be obtained.

However, in order to accurately measure hard objects,
A frequency modulator and demodulator with a fast response speed, in which the container 1, electronic circuit box 4, piezoelectric element 5, contactor 6, etc. are made of hard materials, and can faithfully reproduce sudden changes in the output voltage of the piezoelectric element 5. -D converter, D-A
A converter etc. must be used.

Normal objects to be measured fall somewhere in between, and it is sufficient to use an appropriately designed device depending on the hardness of the object.

In the abdomen of the human body, pressure of several kilograms causes a depression of several centimeters.
When folded, etc., it only dents a few mm. When measuring various locations on various objects using this device, there are various problems such as large dents in the fabric fuselage of a small airplane, and almost no dents in the outer surface of the exterior panel attached to the outside of the frame of a large airplane. This results in a graph G with a slope of .

When measuring the dorsal part of the human body, which has bones in shallow parts, the front of the head, or a carpet placed on a concrete floor, graph G starts out gradually rising, then quickly becomes steep, and reaches the peak. To stand.

In such a case, it is easy to read the graph in the gently sloped part, but it is difficult to read the steeply sloped part, so the printer 21 prints the graph in the horizontal direction (depth).
If you draw out a graph that stretches out the graph, it will be easier to see.

Although the time element does not appear in graph G, for objects that can be plastically deformed, such as clay packed in a bag, contact 6
When the piezoelectric element 5 sinks in, a voltage is generated from the piezoelectric element 5, but when it is pulled up, almost no voltage is generated. This does not happen with elastic rubber, etc. Therefore, if the information obtained during pulling is also used, the computer 18 can determine the degree of elasticity and plasticity of the object.

Graph G is found from graph a and graph E, but
The only parameters are pressure and depth change, and time is not included. Therefore, if it is necessary to add a time element, the printer 21 can print out a graph in which graphs a and E are simultaneously drawn on one graph, with the horizontal axis as a common time axis.

By implementing the present invention, the main parts of the displacement detector of the movable part for determining the depth of penetration of the tip of the contact into the object to be measured can be housed within the movable part, and the size is small compared to the function. Since it is possible to measure one place with one touch, it is possible to measure many parts in a short time.It is also suitable for hardness of the human body, folds, futons, chair seats, the exterior of cars and airplanes, and other object surfaces. It is advantageous to have a measuring device that graphs the depth of the indentation in response to an associated pressure of continuously varying intensity.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a movable part of a pressure-strain diagram recording device embodying the present invention. Figure 2 is a longitudinal cross-sectional view. Third
The figure shows the electrical circuit diagram. FIG. 4 is a graph regarding the motion of the movable part. Figure 5 is a graph of radio waves obtained by FM modulating the voltage in graph C. FIG. 6 is a graph of the output voltage of the piezoelectric element 5. Figure 7 is a graph of the FM modulated radio waves. FIG. 8 is a plan view of the fixing part. FIG. 9 is a block diagram of the electric circuit of the fixed part. FIG. 10 is a graph relating to the motion of movable parts active within the computer 18. FIG. 11 is a graph of the measurement results.

Claims (1)

[Claims] 1. A weight that can be slid in the direction of the cylindrical axis is placed in a small container with a cylindrical interior space with the axial direction facing up and down, and as the container moves, the displacement of the container relative to the weight is converted into an electrical signal and transmitted. a movable part having an electric circuit attached thereto, a contact element for contacting the object to be measured via a piezoelectric element attached to the lower end, and an electric circuit attached thereto that converts the output of the piezoelectric element into an electric signal and transmits it; consisting of a fixed part having an electric circuit for receiving a signal regarding the displacement of the movable part, an electric circuit for receiving an output signal of the piezoelectric element, and a device for graphing the correspondence of the outputs of both circuits;
A device that graphs and displays the depth of depressions corresponding to pressurization on the surface of an object.