JPS6264338A - Position sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a position sensor that detects displacement information of a magnetic body attached to a detection target.

[Technical background of the invention and its problems] Conventionally, a permanent magnet, which is a magnet generating body, is fixed to a detection target, and the position is determined by detecting the magnetic displacement of the permanent magnet with a detection unit installed at a predetermined distance from the target. A position detection device (hereinafter referred to as a position sensor) has been proposed that detects
It is particularly suitable for detecting the movement of a living body such as a human body.

However, although it is preferable to install the detection unit in a state where it is floating relative to a permanent magnet fixed to the living body, that is, in absolute space, if the detection unit is installed completely away from the living body, the living body If there is any careless movement, there is a problem that it will not be able to correspond with the permanent magnet, deteriorating the detection accuracy, and it will be difficult to position and attach the magnetizing body and the detection part, which has low practical value.

[Object of the Invention] The present invention has been made in view of the above-mentioned circumstances.It is easy to install and maintains the correspondence between the magnetizing body and the detection unit even if the detection target moves unexpectedly. It is an object of the present invention to provide a position sensor that can perform the following functions without reducing detection accuracy.

[Summary of the Invention] In order to achieve the above object, the present invention provides a detecting section consisting of two equivalent magnetic cores or two magnetic cores in which at least two coils are wound around one or two high magnetic permeability magnetic cores, and A position sensor consisting of a detection circuit that processes a signal obtained from a sensor, a fixed member installed on a detection target, and a magnetic body fixed on the fixed member and giving a signal to the detection section, the fixed member being In addition to having a disk shape of 8 to 13 mm, the magnetic generating body is characterized in that it is cylindrical with a diameter of 2.5 to 5.5 mm.

[Embodiments of the invention] (Eso lower residual color) The present invention will be specifically explained below using Examples.

FIG. 1 is a schematic diagram of an embodiment of the apparatus of the present invention.

This device includes a permanent magnet M as a magnetic body fixed to the surface of a living body 8 to be detected, a detecting section 1 installed at a predetermined distance from the permanent magnet M, and a signal from the detecting section 1. The detection circuit 2 which processes the signal and outputs the output Eout is checked. The detection unit 1 is made of an amorphous wire AF (composition 'C0611F
eaS i+38+s atomic%.

2 coils HIf + H2 on both sides (110um diameter)
The permanent magnet M has a disk shape with a fin diameter of, for example, Z, , t, and 3 to 1.
It is fixed to the surface of the living body 8 with an adhesive or the like via a synthetic resin disk 7 which is a fixing member having a diameter of three fins. The detection unit 1 detects the living body 8 via the positioning member 3.4.5°6.
It is attached to the surface of the permanent magnet M, and is positioned so that the tip of the detection part is kept at a predetermined distance from the permanent magnet M. The positioning member includes a glass tube 3 in which the detection part l is fixed, a bowl-shaped synthetic resin frame 4 fixed to the glass tube 3 via a rubber 5 serving as a vibration isolator, and this synthetic resin frame. 4 and a rubber 6 serving as a vibration isolating material for fixing the body 4 to the surface of the living body 8.

With this configuration, since the permanent magnet M is fixed to the surface of the living body 8 via the synthetic resin plate 7, it is extremely easy to fix it, and it moves following the movement of the living body, whereas the detection unit 1 Since it is connected to the living body 8 via a positioning member in which two vibration isolators 5.6 are inserted, small movements of the living body (movements that should be detected) are absorbed by the rubber 5.6 and are not transmitted. Although it is possible to accurately detect the displacement information of the permanent magnet because it moves only by following the large movements (inadvertent movements) of the living body, the correspondence between the permanent magnet and the permanent magnet due to the careless movement of the living body can be detected accurately. You will be able to maintain your relationship.

This will be explained using experimental data shown in FIG.

Figure 2 shows measurement data obtained when a position sensor is attached to the human body to be measured and the body is rocked back and forth while sitting on a chair. In the case where the vibration isolating material is installed without intervening, the figure (b) shows the vibration isolating material.

Here, since the large serrations of the magnet M, which is the magnetizing body, and the size of the synthetic resin disk 7, which is the fixing member, greatly affect the detection waveform and detection sensitivity, the experimental results regarding this point are shown in Figs. 3 to 6. This will be explained using figures. In both cases, data is shown when a phonocardiogram was measured on a human subject sitting on a chair.

Figure 3 shows a synthetic resin disk 7 with a constant diameter (1 Q mm in diameter, 1 Q mm in thickness).
This is measurement data in 8 values when the diameter of the magnet M fixed thereon is changed as mm). As shown in the figure, the amplitude of the waveform is large for 2 mm and 2.5 mm, and small for 5 mm and 10 mm.

In Fig. 4, the size of the magnet M is constant (diameter 5), contrary to Fig. 3.
mm, thickness 2 mm), synthetic resin disk 7 (thickness 1 m)
The data shows 8 values when the diameter of m) is changed. As shown in the figure, the amplitude of the waveform is large at 7.5 mm and lQmm, but at 12.5 mm, 15 mm,
17.5mm.

As the distance increases to 20 mm and 22.5 mm, the amplitude decreases successively.

FIG. 5 is a graph in which the sensitivity G and linear range W of the sensor were measured when the diameter of the J-unimagnet M in FIG. 3 was changed, and the linear output GXW was determined.

As is clear from the figure! The best characteristics are shown when the iEiM diameter is around 5 mm.

FIG. 6 shows a characteristic diagram obtained by measuring the displacement of the object to be detected when changing the direction of J in FIG. 4: sea urchin synthetic resin disk (plastic plate). As is clear from the figure, the best results are shown in the vicinity of 10 mm.

As is clear from the above, the diameter of magnet M is 2.5 m.
m to 6.5 mm, preferably 5 mm. The diameter of the synthetic resin disk is in the range of 6 mm to 13 mm,
Preferably 10 mm2Fi: If selected, good centering can be obtained.

Note that the present invention is not limited to the above-mentioned configuration, and various modifications can be made.

For example, the detection unit 1 is not limited to having 21 equivalent cores, but may have a two-core configuration in which two amorphous wires are arranged in a straight line with a predetermined interval and the coil is wound around each.

Further, the shape of the permanent magnet, the fixing member, or the positioning member is not limited to a circular shape, but may be a square shape or the like.

Furthermore, the number of the vibration isolators 5.6 may be only one.

Next, an application example for detecting displacement information of a living human body using the device will be described with reference to FIG. 1 and subsequent figures. Note that although a combination of a multivibrator circuit and an active filter is shown here as a specific configuration of the processing circuit 2, the active filter is not an essential component.

In FIG. S, 1 is the detection section, and signals obtained from both ends of the detection section are signal lines N,,j! 1 respectively through the transistors 'rr,, Tr= and the signal line! ,.

The signal is input to the active filter ACF via 14. Each transistor TrI.

The outputs of the commutation circuits (consisting of capacitor CI and resistor R1) connected to each signal line g, , g, are crossed and applied to the base of T r t. Further, a load resistor RL+RL is connected in series between the signal lines 1s and la, and a variable resistor VR is connected in parallel with this, and the connection point of this resistor VR and the resistors RL and RL is commonly grounded. Incidentally, the coil H1? + HIT, a power supply voltage E is applied, and an output EouL can be taken out from the active filter ACF. Specifically, this circuit is configured as a multi-vibration bridge using two equivalent magnetic cores. It should be noted that each magnetic core in the two magnetic cores is selected to operate in a rotating magnetization region.

In addition, the active filter ACF allows selection of filter characteristics, for example: ■ Cutting 50 Hz or more, ■ Cutting 20 Hz or more.
Cuts above 11z, ■Cuts below 20Hz, ■DC
Various modes such as passing through both the ~20 Hz band and the 20 Hz ~ 50 Hz band can be selected.

When a micro magnet M is placed near the coil in a circuit with such a configuration and is moved relative to the coil HIT,
The relationship between the moving distance MX (ms) and the output Eout (mV) is as shown in FIG. In the same figure, N1 to N are the changes in the number of turns of the coil, and Nl = 15
0 (Turns), N, -300 (Turns), N
s = 450 (Turns), and the current supplied to the coil is 1 = I Q O (m^).

Moreover, the micro magnet M used was one with an S-diameter height of 1.5 M.

As is clear from the figure, the detection sensitivity increases as the function N increases. Furthermore, in either case, linearity (nonlinearity <1% FS) is exhibited up to a large displacement of 6 fl, and the displacement of the magnet can be detected accurately.

The results of detecting biological information using the device will be explained.

FIG. 2 shows the fixed position of the permanent magnet M by the device (hereinafter also referred to as sensor), and shows the periphery of the human body P including the heart at six points in the vertical direction (A-F) and six points in the horizontal direction (1 to 1). 6)
The purpose is to detect cardiac displacement information regarding 36 points by dividing the data into a matrix of 36 points. Note that point A-3 corresponds to the base of the heart, and point F-2 corresponds to the apex of the heart. Moreover, the E-2 point corresponds to the groove drop. In this case, micromagnets may be attached to all of the points, or a single magnet may be attached for each measurement.

The results are shown in Fig. 1. This data was obtained with the active filter AF operating at 5 to 50 Hz.

In the figure, since the waveform at point B-6 seems to contain various information, various analyzes were performed based on the information at this position, and the results shown in FIG. 11 were obtained.

Figure 1I (a) is a waveform obtained by preparing an electrocardiograph separately from the device of the present invention and obtaining an electrocardiogram at point B-6, and Figure 1I (b) is a waveform obtained at point B-6 in Figure 4. Point center displacement diagram (in other words, a diagram showing the output of the sensor according to the present invention as it is)
, the same figure (c) is 20 in the above-mentioned cardiac displacement diagram waveform.
) DC through a filter that cuts components higher than lx
This is the waveform obtained from the 2011z information. The same figure (d) is the same (20Hz to 5011z waveform obtained by canting the component of 20Hz or less in the heart displacement diagram waveform).

Here, as a result of examining the waveform in Figure 1 (c), it was found that it was almost completely inferior to the pulsation diagram.

As a result of examining the waveform shown in FIG. 4(d), it was found that it almost coincided with the phonocardiogram. In other words, the first peak is the first note (
This is the sound produced by ventricular contraction, which is a combination of the ventricular contraction sound and the atrioventricular valve sound), and the next peak is the second sound (the sound produced by ventricular relaxation, which is the closing sound of the aortic valve). be.

Based on the above results, the waveforms at the base of the heart (point A-3) and the apex (point F-2) were analyzed, and the results shown in FIGS. 72 and 13 were obtained.

Figures tZ(a) and 8(a) show electrocardiograms, with the first
Figure 2(b) and Figure 7.3(b) are phonocardiograms obtained by applying a bandpass filter of 20 to 50Hz, and Figures 72(c) and 13(e) are phonocardiograms obtained with a bandpass filter of 20 to 30Hz. Filtered phonocardiograms, Figures 1211(d) and 8(d)
) is a figure obtained by applying a 30-40Hz bandpass filter, and Figures 12(e) and 73(e) are 40-5011
It is a diagram obtained by applying a Z band pass filter. Moreover, FIG. 72(f) and FIG. 7j(f) are pulsation diagrams obtained by applying a filter of 0 to 51Z.

As is clear from both figures, from the obtained cardiac displacement diagrams, 20~
When extracting the components included in the range of 501Lz, each figure (b
), as in (c) (a clear phonocardiogram can be obtained,
And when the components in the range of 0 to 5 Hz are extracted, each figure (f
), clear basal and apical pulsatograms could be obtained.

From the above, it can be seen that the sensor output shown in Figure 1 (b) is a heart sound wave of 2 (H1z) or more superimposed on a pulsation wave of about 2011z or less. Therefore, biological information (
For example, even if you look at Figure 77(b) as it is, it is a living emotion! (or any useful information), pass this sensor output through an active filter, separate it into a phonocardiogram of about 20112 or more and a pulsatogram between DC and about 2082, and collect data. It turns out that this has an important meaning.

The biological information obtained from a desired position using the device of the present invention as described above is hereinafter referred to as a cardiac diagram. By applying a filter of a desired value to a cardiac diagram obtained from a desired position, a heartbeat diagram and a phonocardiogram can be easily obtained. Moreover, by obtaining a cardiac diagram of each point in a matrix over a wide range, it is possible to obtain effective information as described below.

1I1. The figure shows the time course of the chest wall displacement distribution due to pulsation using contour lines. Each measurement value is not measured simultaneously, but is the instantaneous value of the pulsation wave at each measurement point.
It is read based on the waves.

The pulsation waves and electrocardiograms of healthy people at rest are regular and the reproducibility of each cycle is high, so the contour lines in the diagram are approximated when each measurement point is measured simultaneously. In the same figure, (a) shows the case where the wave is generated simultaneously with the ECG R wave, and (b) to (d) show the case where the wave elapses sequentially every 0.2 seconds. The base t$ value (0 value) of displacement was the minimum value of each pulsating wave. In the same figure (a), the left atrium is 15~
It is elevated by 20 μm, and in (b) it is 15 μm at three locations near the left ventricle.
It rises by more than m and the highest value is 25 μm. (C) again (
A similar pattern is shown in (a), and in (d) the raised points extend to the left ventricular side, and in (e) they return to a pattern similar to (a).

Conventional pulsatograms using microphones measure chest wall vibration pressure, and that pressure is the sum of vibrations over the entire circular area with a diameter of 51 mm, making it difficult to detect local displacements of the chest wall. The magnetic sensor of the present application detects local displacement. In this case, the possibility of vibration of the diameter/mouth sensor core fixing frame itself is considered, but since the pulsation is a local phenomenon, the pulsation transmitted to the bottom of the frame of approximately 101 long rings is smoothed. Therefore, it is thought that the DC component appears as a bias in the sensor output. Therefore, these pulsatograms included only the 0.5-511z portion of the sensor output.

In this way, by obtaining biological information in a matrix as shown in FIG. 5 using the detection device of the present invention, it is also possible to specify the site of a heart defect by, for example, measuring the area around the heart. Naturally, it is also possible to check the state of cardiac function.

The present invention is not limited to the embodiments described above, and various modifications are possible.

Although the above embodiment detects the displacement state of the heart, it goes without saying that it can be applied to other parts as well.

FIGS. 15(a) and 15(b) show carotid artery wave and wrist measurement data before exercise, and FIGS. 1D (a) and (b) show carotid artery wave and wrist measurement data after exercise.

In either case, the results are almost the same as those detected by existing pulse wave meters, indicating that the pulse waves are faithfully reproduced.

〔Effect of the invention〕

As described in detail above, in the present invention, the magnetizing body is fixed to the detection target via a fixing member having a wider area than that, so fixing is easy, and the detection part is isolated from the magnetizing body for a predetermined period to prevent Because it is fixed to the detection target using a positioning member via a vibrating member, it is easy to install, and the relative position of the detection target to the magnetic body can be maintained without changing due to careless movement of the detection target. Since the movement based on the information to be detected is not directly transmitted to the detection unit, highly accurate detection can be performed. Good characteristics can be obtained by selecting the sizes of the magnetizing body and the fixing member within a predetermined envelope.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of an embodiment of the device of the present invention, Fig. 2(a),
(b) is measurement data for explaining the present invention in detail, FIGS. 3 and 4 are experimental data when the diameters of the magnetizing body and the fixing member are changed, respectively, and FIGS. 5 and 6 are respectively the experimental data. 3 and 4, FIG. 7 is a circuit diagram showing an example of application of the device of the present invention, and FIG. 8 is a characteristic diagram thereof.
FIG. 9 is a front view for explaining the detection points of the device, FIG. 10 is the displacement data obtained by the device at each point, and FIG. 11 is the data of the specific point in FIG. The electrocardiogram, cardiac displacement diagram, electrocardiogram corresponding diagram, and phonocardiogram are used when performing analysis based on the data of specific points in Figure 10. In each figure, <a> is an electrocardiogram, (b) to (e) are phonocardiograms for each frequency component, and (F) is a pulsatogram. Figure 14(a)
~(e) is a temporal transition diagram of chest wall displacement distribution due to pulsation. Figures 15 (a) and (b) show detection data for the carotid artery and wrist before exercise, and Figures 16 (a) and (b) show detection data for the carotid artery and wrist after exercise.1. ...Detection unit, 2...Processing circuit, 3.4...Positioning member, 5, 6...Vibration isolation member, 7
... Fixed member, 8... Detection target, 1-(IT,
2 T... Coil wound around equivalent two magnetic core amorphous, M... Magnetic generator, Trl, i"r2... Transistor, 8CF... Active filter. Agent: Masayoshi Misawa, patent attorney 7. 5mm 10mm 2.5 mm mm mm 17.5mm 0mm η, 5mm 5mm Fig. 4→+← To Φ

Claims (1)

[Claims] A detecting section consisting of two equivalent magnetic cores or two magnetic cores with at least two coils wound around one or two high magnetic permeability magnetic cores, a detecting circuit that processes the signal obtained from this detecting section, and a detecting section installed at the detection target. In the position sensor, the fixing member has a diameter of 8 to 13 m.
m, and the magnetizing body has a diameter of 2.5 to 60 mm.
A position sensor characterized by having a cylindrical shape of 5 mm.