JPH04204261A - Method and apparatus for detecting speed - Google Patents

Abstract

PURPOSE:To achieve the simple detecting method and the high detecting accuracy by forming a double structure for a surrounding body wherein inner and outer gases pass at the respective inherent time constants, detecting the difference between the inner and outer pressures at the upper and lower two points at the boundary, and detecting the difference between the detected pressures as the speed signal. CONSTITUTION:A unitary body is formed of two capacitor microphones 6 and 6 and a linking tubular body 13. The central point of the entire unitary body is made to agree with the central point O of a cylindrical case 14 wherein a plurality of holes 14a are provided in both upper and lower ends. The parts are arranged so that they are symmetrical at the upper and lower sides and the right and left sides with respect to the central point O as the reference. A space S between the unitary body of a pair of the capacitor microphones 6 and 6 and the linking tubular body 13 described above and the case 14 is uniformly filled with cellular material such as sponge and non-woven fabric for imparting flow rate resistance to the circulation of air.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speed detection method and apparatus for detecting speed in the vertical direction.

[Prior Art] Conventionally, this type of speed detection device has been used as a vertical speed meter for aircraft, so it will be explained using this as an example. That is, this vertical speed meter is as shown in Fig. 8, in which one box (1) houses the other box (2), and each of the boxes (1) and (2) ) are provided with orifices (3) and (4).

The inner diameter of the orifice (3) of the one box (1) is larger than the inner diameter of the orifice (4) of the other box (2), and the flow resistance is set to be small.

As a result, when the speed sensor is displaced upward, for example, the atmospheric pressure decreases in proportion to the height, and the pressure within the one box (1) also decreases immediately.

On the other hand, inside the other box body (2), there is a minute orifice (4
), the air slowly flows out, and its internal pressure also decreases more slowly than the pressure inside the one box (1).

The resulting pressure difference between the inside and outside of the other box (2) is
It is converted into an electrical signal by a differential pressure sensor (5) attached to the box (2), and output as a signal proportional to the lifting speed.

[Means for Solving Problem S] However, such conventional devices are expensive because they are for aircraft use, and are large in size, making them difficult to handle.

Therefore, for example, if you try to measure the vertical movement speed of a person's body while exercising, and if you wear a device on your body and exercise, the device will get in the way and the human movement will be affected by the device, making it normal. There have been problems in that the device cannot operate, making measurement difficult in some cases, and even if measurement is possible, the measurement is not accurate.

Therefore, in consideration of the above points, the small size and lightweight,
The present invention proposes a method and device for detecting vertical speed that can be easily used by anyone and that can measure, for example, the vertical speed of a human body during exercise, which has been difficult to measure up until now.

[Means for Solving the Invention] This invention has been made by focusing on the principle of an aircraft vertical speed meter. A second enclosure having a function of allowing internal and external gas to flow with a second time constant set smaller than the first time constant is provided outside the enclosure, and a second enclosure is provided on the opposite surface of the first enclosure. This method detects the pressure difference between the first enclosure and the second enclosure using two elements, and further detects the vertical speed based on the separately detected pressure difference. A space in a first cylinder having air circulation holes bored in its surface is partitioned by a pair of partition walls separated by a predetermined distance and having an air leak path, and the amount of deflection of the partition wall is detected for each of the pair of partition walls. Further, the first cylinder is covered with a second cylinder having air circulation holes formed in the wall surface, and the difference in the amount of deflection of each of the pair of partition walls is output as an acceleration signal. .

[Function] As mentioned above, the enclosure, in which the inside and outside gases flow with their own time constants, is made, for example, of a double structure, and at the boundary, the pressure difference between the inside and outside of two points, upper and lower, is detected, and the detected pressure is Since this method detects the difference in speed as a speed signal, the detection method is simple and the detection accuracy can be improved. Furthermore, when the speed detecting device configured as described above is displaced in the atmosphere, for example, upward, the air inside the second cylinder is moved to the outside and the first cylinder is moved upward.
The air in the partitioned space inside the cylinder leaks into the second cylinder, and the time constant of the leakage is different, so that the partition wall provided in the first cylinder can detect the displacement speed of the speed detection device. The deflection amount is detected as an electrical signal indicating the vertical speed, so it is low cost and
A compact speed detection device is obtained.

[First Embodiment] Before describing an embodiment according to the present invention, the structure of a condenser microphone (6) used in the following explanation will be explained based on FIG. 1. This condenser microphone (6) has been widely used as a part of audio equipment, and has been used for boat fishing (for example, Brimo IC).
EM-EM-121>, detailed explanation will be omitted.

(7) is a case with a hole (7a) for taking out lead wires at the bottom, (8) is a circuit board to which an FET transistor (9) is attached, and the circuit board (8) is connected to the case (7). A drawer (not shown) is inserted through the hole (7a).
is brought out to the outside. (lO) is a cylindrical spacing/supporting member with openings at both upper and lower ends, and its upper end surface (10a)
The electret film (partition) (lla) and its counter electrode (
llb) is clamped throughout.

Note that one terminal (9) of the FET transistor (9)
a) is the counter electrode (
11b).

Next, a vertical speed meter (vertical speed device) using a condenser microphone (6), which is one specific example of the present invention, will be described in detail based on FIGS. 2 to 4. In the drawings, the same reference numerals are used to denote the same components or equivalent components as those in FIG. 1, and redundant explanation will be omitted.

(13) is a cylindrical connecting tube (13) with openings at both ends, and condenser microphones (6) and (6) with the same characteristics are attached to the openings at both upper and lower ends of the electret film (13), which is the pressure receiving surface of each. lla) is the predetermined interval L
(2) facing each other with a gap between them, and the airtightness of the space is maintained. (with full contact across the entire surface). In other words, the two condenser microphones (6) and (6) are connected to the connecting cylinder (
13) and are integrated into both ends. Furthermore, the two integrated condenser microphones (6) and (6) and the connecting cylinder (13) have a plurality of holes (14a) at both the upper and lower ends of the center point of the integrated unit.
is arranged so as to coincide with the center point O of the cylindrical case (14) in which the cylindrical case (14) is perforated, and is symmetrical vertically and horizontally with respect to the center point O (with respect to the center lines X and Y).
It is arranged so that In addition, the space S between the pair of integrated condenser microphones (6) and (6), the connecting cylinder (13), and the case (!4) provides flow resistance to air flow. Sponge, non-woven fabric, etc. for sponges (not shown) are evenly distributed (with uniform density)
Filled. Please note that the above condenser microphone (
The hole (7) drilled in each case (7) of 6)
The flow resistance of a) is set to be the same, and the multiple holes (14a) bored in the case (14) are set to be the same.
) are also set to be the same, but these flow resistances are set small and can be ignored.

Next, the theory of detecting the lifting speed using the above configuration will be explained based on FIG. 2.

First, constants and variables used in this explanation are defined below.

(Constants and variables of condenser microphone (6)) C:
In the ntt space between the pressure receiving surface (corresponding to the electret film (lla)) and the opposing IE pole (Ilb) - Sensitivity R: Input impedance r of the FET transistor (9)
-For mounting on the pressure receiving surface (electret film (11a)
) (Fig. 3(A),
As shown in (B), each member (7), (11a), (+
Between the contact surfaces between t b), (+2), (8), and (10), there is a small gap R due to dimension f: error, etc., and this is caused by air flowing through the gap R. ) P,: Pressure behind the pressure receiving surface P,: Pressure on the pressure receiving surface q: Flow rate of air passing through the gap between the pressure receiving surface mounting e: Output voltage Note that as a subscript of the above constants and variables, the first capacitor The microphone (located on the upper side in FIG. 2) is numbered 1, and the second condenser microphone (located on the lower side in FIG. 2) is numbered 2.

(Constants and variables of cylinders (13) and (14)) Lo; Length of second cylinder (corresponding to case (14)) ■ First
cylinder (both condenser microphones (6) and (6)
) electret films (lla) and (lla)
The air volume of the connecting cylinder (13) formed between the two condenser microphones (6) and (6)
) Ll (+2) Upper wall surface (lower wall surface) of the second cylindrical body (14)
From the condenser microphone (6>Length l to the pressure receiving surface, the second cylinder (14) and the first cylinder (13) in the vertical direction
center deviation d・Flow resistance per unit length due to air flow in the cavernous body in the second cylinder (14) (other constants and variables) g0 Gravitational acceleration ρ: Total air density h Device according to the present invention Height displacement from the reference point (initial value of displacement, e.g. sea level, ground surface, etc.) V: Horizontal velocity t - Time f: Frequency S - Biplane angular frequency f, , ~f, ,: Human Frequency range of vertical motion We also make the following assumptions.

■There are small air leakage paths (Figure 3 (A) and (
There is R) in B), and its leakage resistance is assumed to be linear.

(2) The filter characteristics due to the holes (14a) of the second cylindrical body (14) are ignored, and the air pressure inside the second cylindrical body (14) is assumed to be equal to the atmospheric pressure without noise.

(2) Air circulation in the first and second cylindrical bodies (13) and (14) is -dimensional in the sensor axis direction (Y direction).

■The spatial volume Ve of the second cylinder (14) is the same as that of the first cylinder (14).
It is larger than the space volume V of 3).

(2) The pressure before and after the pressure receiving surface (lla) and (lla) of the condenser microphones (6) and (6) and the pressure before and after the electrode (llb) surface as a capacitance are the same. Although pressure affects capacitance, electrostatic force acting on capacitance does not affect pressure.

Next, based on the above premise, both condenser microphones (6) and (6) used in this embodiment are expressed by the following equations.

-p-+ (jN p :+(t)-1) e+(t) 9 (door □ -p -2(t)1 Also forms the pressure receiving surface of the condenser microphones (6) and (6) Electret film (lla) and (
11a) The respective equations for the pressure across the surface are as follows:

p・1(j)=-S (Q +(j)÷92(t)l
d td2h(t) One house, □ t2 Also, the equation of the pressure behind the pressure-receiving surface of the second cylinder (14) (the space around the FET h run transistor (9) of the condenser microphone (6)) is as follows. become that way.

Laplace transform these equations to obtain the height displacement h(S)
From, both microphone output voltages e1(s), e
Find the transfer function up to 2(S).

Now both condenser microphones (6) and (6)
If both are the same product and have the same characteristics, CI"c 2 = C, RI: R2: R, K + = K 2"
It is considered that K, r, = r2 = 2r, L1 = L2.

At this time, both condenser microphones (6) and (
If we take the sum e, (s) of the output signals A and B in 6), we get e
, (s)=e 2(s)−e , (s).

In addition, the above two condenser microphones (6) and (
Focusing on one of 6), the transfer function from the vertical speed of the sensor to the output of the condenser microphone is determined by the product of the following three transfer functions.

e (s)=-G1(sL crr(s)-G3(s
:l V-(s)G3=211052+Ds+
ρg Next, each of the above transfer functions will be considered.

The incomplete differential transfer interval G1(s) is a transfer function specific to the condenser microphone (6). In order to capture the vertical motion speed, −< f,,.

It must be 2πRC. When the capacitance C of the capacitor microphone (6) is 10 to 20 pF and the input impedance of the FET transistor (9) is IQIll to 10Ω, the cutoff frequency of G+(s) is 1.6 Hz. Furthermore, if a FET l-transistor with a large input resistance of 1.2 digits is used, it is possible to measure even the slow up and down movement of a human being, and the transmission interval number G2(S) must satisfy the following equation.

fl, Ak□ 2πrv Next, regarding the transfer function Gm(S), which I discovered during this development, this transfer function G3
(S) has an anti-resonant characteristic, and when its anti-resonant frequency is in the following frequency range, it significantly disturbs vertical velocity measurement. It is difficult to evaluate the flow resistance d, so let d = 0, for example, 1 = 1.24 mm -12,
When calculating the reverse resonance frequency in the case of 4 cm, it is IHz ~ 10H
It becomes z. If the cylinder (13) is not carefully placed, it can easily cause anti-resonance at meaningful frequencies. To avoid this, set 1=0. That is, the case (14) and the cylindrical body (13
), especially the center in the contraction direction.

This gives the overall transfer function:

Here, due to the roughness of the cavernous body in case (14), D(
Or d) is determined, and D that satisfies the following equation can be selected.

A condenser microphone (R, G
3. Cylinder (r, V), arrangement of cylinder (1), corpus cavernosum (
d) by selection fl,. In the frequency range of ~f 11 mw, the output voltage of the condenser microphones (6) and (6) is proportional to the vertical speed. If the acceleration can be completely canceled out,
The output is proportional only to the vertical speed, regardless of the sensor's orientation or direction of movement.

Next, the detection outputs A and B output from each of the condenser microphones (6) and (6) configured as shown in E above are supplied as input signals to the circuit configuration shown in FIG. Next, the circuit configuration will be explained.

In the figure, (15) is an adder circuit which inputs the detection outputs A and B output from the condenser microphones (6) and (6), respectively, and receives the input signal A.
and B are added together and output. (16) is a band pass filter that extracts only the signal component related to the vertical speed from the signal output from the adder circuit (15). (1
7) is a first comparison circuit which has a first reference value, inputs the output from the bandpass filter (16), compares the input signal with the first reference value, and compares the input signal with the first reference value. If it is smaller than the value, the output is set to high level. (18) is a second comparison circuit having the same function as the first comparison circuit, and has a second reference value larger than the first reference value, and the output signal supplied from the bandpass filter (16) is the second comparison circuit. If the bond is larger than the standard bond, the output is set to high level. (19) is the first oscillation frequency circuit, and when a high level signal is supplied from the first comparison circuit (17), the first oscillation frequency of, for example, 100Hz is applied only while the high level signal is supplied! ! Shake. (20
) is a second oscillation circuit which has the same function as the first oscillation circuit (19), and when a high level signal is supplied from the second oscillation circuit (1B), the first oscillation circuit Wa
It oscillates at an oscillation frequency greater than the fIi number.

(21) is a drive circuit, first and second oscillation circuits (19)
In response to the oscillation output supplied from the and (20), the notification section (22) generates a high-frequency sound or a low-frequency sound.

Note that the device configured as described above is housed in one case (a separate case different from the case (14)),
For example, it is used as a biofeedback device by being attached to a person's head, waist, foot, etc.

Next, the operation of the above structure will be explained.

The device shown in Fig. 2 is displaced vertically (while keeping the Y-axis in the vertical direction), for example, upward from the ground surface, and the center point ○ of the second cylinder (L4) is moved. If the height from the ground surface (not limited to the ground surface, but a certain point in space may be set as initial A1) is expressed as h (t), the air pressure around the device will drop by 9 g h (t).

As a result, the condenser microphone (
The air in the space sandwiched by the condenser microphones (6) and (6) flows from the periphery of the electret film (Ila) that forms the pressure receiving surface of both the condenser microphones (6) and (8). (6) The air leaks out at a predetermined time constant (first time constant) toward the space inside the condenser microphone (6) case (7).
It flows out toward the corpus cavernosum from the hole (7a) formed in the corpus cavernosum (time constant close to 0), and is attenuated by the time constant (second time constant) of the corpus cavernosum. The attenuation process is detected by both condenser microphones (6) and (6). Each of the detected pressure signals A and B is supplied to the addition circuit (15) shown in FIG.
) to remove noise.

After that, the first comparison circuit (17) and the second comparison circuit (18)
) are supplied to each of the, each! The first setting
It is compared with the reference E and the second reference value, and if the extracted vertical speed signal is smaller than the first reference value of the first comparison circuit (17), a high level signal is supplied to the first oscillation circuit (19). A low frequency signal is supplied from the first oscillation circuit (19) to the sound sensor (22) via the drive circuit (21), and a low frequency sound is emitted. Further, if the magnitude of the vertical speed signal output from the band pass filter (16) is larger than the second reference value of the second comparison circuit (18), a high level signal is supplied to the second oscillation circuit (20). A high frequency sound is emitted by supplying a high frequency signal from the second oscillation circuit (20) to the notification section (22) via the drive circuit (21). Also, band pass filter (16)
When the magnitude of the vertical speed signal output from is between the first reference value and the second reference value, the first and second ratio *1
Since low level signals are supplied from the two circuits (17) and (18) to the first and second oscillation circuits (19) and (20), their respective oscillations are stopped and the notification section (
No sound is emitted from 22). That is, by combining the sensor shown in Figure 2 above and the circuit block shown in Figure 4 into a unit and attaching it to a person's head, waist, legs, etc., it is possible to swing like a professional without having to move the head up and down. I can practice. Also, you can enjoy a marathon without getting tired without having to raise and lower your legs. Furthermore, by attaching it to the foot, elderly people can raise their feet high and take a walk, which is very useful.

[Second Example] In the above example, the gR circumference of the corpus cavernosum (not shown) was covered with a case (14), but as shown in FIG. The corpus cavernosum may be formed into a bag shape and placed inside the bag and covered.In this case, the thickness of the corpus cavernosum in the trenches of both condenser microphones (6) and (6) is set to be the same. .

[Third Embodiment] This embodiment is an improvement on the one shown in FIG. 5, and includes a ring-shaped adhesive layer all around the hole (7a) formed on the back side of both condenser microphones (6) and (6). (25) may be provided, and a spongy body such as a sponge or nonwoven fabric may be pasted on the entire upper side thereof.

In addition, in the actual IMPA mentioned above, a capacitor microphone is used to detect the vertical velocity, and the detection is not limited to force. Needless to say, elements etc. may be attached.

In addition, in the above embodiment, two condenser microphones (
6) and 6), the electret film (ll
Although the condenser microphones (6) and (6) are arranged facing each other so as to face each other, it goes without saying that the condenser microphones (6) and (6) may be positioned so that they are facing each other by rotating their respective directions by 180 degrees. do not have.

[Effects of the Invention] As described above, the present invention provides a second time constant that is set smaller than the first time constant on the outside of the first enclosure that has the function of allowing internal and external gas to flow through the first time constant. A second enclosure having a function of allowing internal and external gas to circulate is provided, and two elements placed on opposing surfaces of the first enclosure detect the pressure difference between the first enclosure and the second enclosure. This is a speed detection method that further detects the vertical speed based on the difference between the separately detected pressures, and a pair of air leakage paths are provided in the space of the first cylinder, separated by a predetermined distance. A partition wall is provided, and each of the pair of partition walls is provided with a pressure detection means for detecting the amount of deflection of the partition wall, and further the pressure detection means is provided to cover at least the air leakage path of the first cylindrical body, and the flow rate of the air leakage path is A speed sensor characterized in that a flow resistance imparting means having a flow resistance smaller than the resistance is provided, and a physical quantity indicating a difference in the amount of deflection of each of the pair of partition walls is output from the pressure detection means as a speed signal. Therefore, it is possible to make the vertical speed detection device more compact, smaller, and lighter, and the cost can be reduced without being expensive, which is an extremely large effect that has never been seen before. In addition, since the detection device can be made compact and lightweight in this way, it becomes possible to measure the movements of a person during exercise, thereby making it possible to train athletes to move efficiently.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional explanatory diagram of a condenser microphone used in an embodiment according to the present invention, Fig. 2 is a structural cross-sectional explanatory diagram for explaining the first embodiment, and Figs. 3 (A) and (B) are An enlarged sectional explanatory diagram of the main parts of portions A and B in FIG. 1 to explain leakage, and FIG. 4 is a signal processing circuit for processing electrical signals output from the condenser microphone (6) shown in FIG. 2. and - A circuit block diagram of a lifting needle showing a specific example, FIG. 5 is a second embodiment, FIG. 6 is a diagram showing an improved product of the second embodiment shown in FIG. 5, and FIG. 7 is a diagram of the first embodiment. FIG. 8 is a cross-sectional explanatory diagram showing a conventional example. 6... Condenser microphone 7...
...Case 7a, 14a...
- Hole 8...Circuit board 9...
...FFTl-transistor 11a...Electret film 11b...Counter electrode 12...Spacer 13...
...... Connection cylinder 14... Case 15... Addition circuit 16... Band pass filter 17.18
......Comparison circuit 19.20...
...Oscillation circuit 21... Drive circuit 22.
・・・・・・・・・Notification Department 23.26・・・・・・・
...Cavernous body 25...Adhesive layer Fig. 1 Straw 30 (A) Fig. 3 (B) Fig. 2 j'': 1. Figure 4 Figure 5

Claims (2)

[Claims] (1) Has a function that allows internal and external gas to flow through the outside of the first enclosure with a second time constant that is set smaller than the first time constant. A second enclosure is provided, and a pressure difference between the first enclosure and the second enclosure is detected by two elements arranged on opposing surfaces of the first enclosure, and the separately detected pressures are detected. A speed detection method that detects vertical speed based on the difference between (2) A pressure detection means that includes a pair of partition walls that are separated by a predetermined distance and have an air leak path in the space of the first cylinder, and that detects the amount of deflection of each of the pair of partition walls. furthermore, a physical quantity indicating a difference in the amount of deflection of each of the pair of partition walls from a flow resistance means that covers at least the air leakage path of the first cylindrical body and is smaller than the flow resistance of the air leakage path. A speed sensor characterized by outputting a speed signal.