JPS6046478A - Distance measuring device - Google Patents

Abstract

PURPOSE:To measure accurate distance through a simple ciruit with an ultrasonic wave pulse by sampling and holding a receive signal at every oscillation period, comparing two successive signals to decide the arrival time point of a reflected wave when the signal comparison is reduced. CONSTITUTION:An ultrasonic wave pulse radiated by an ultrasonic wave oscillator 11 is reflected by a target to enter a receiver 12. The receive signal is inputted to the 1st sample-and-hold circuit 103 to hold the maximum in every oscillation period with an analog switch 103A successively, and it is outputted from an amplifier 103B as a hold signal 1h. The signal 1h is held in a holding circuit 104 as the 2nd hold signal 1i elasping a specific time after sampling timing. The signals 1h and 1i are compared with each other by a comparing circuit 105, which outputs a peak detection signal when the signal 1i becomes larger to measure the time of reflected wave arrival.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a distance measuring device, and in particular to a distance measuring device that emits ultra-waves in the form of pulses toward a target (f5) and is based on the time from light (4ti) to arrival of reflected waves. The distance to the target object j is measured using a distance measuring device.

Conventionally, this type of device detects the arrival of a signal when the reflected wave reaches a certain level, but the reflected wave becomes attenuated during transmission, resulting in a loud roar. : hard or soft target or transmission medium (t:i is air)
Because the extent of the attenuation of rIa + body J and C is to blame,
With the detection method described above, the exact arrival point cannot be determined.

By the way, as mentioned above, the reflected wave strong electricity of the supersolar wave that has been transmitted in a pulse-like manner fluctuates in various stripes, but the strong electricity of η anti-Q 1 wave shows a peak around the mountain. It is known that points are invariant. -Use the lever to detect the peak of the reflected wave.11 Ultrasonic light 1λJ, and the peak of the reflected wave (Measure the time opening of 2). r can know.

The present invention is based on the above principle, and provides a distance measuring device that uses an extremely simple and inexpensive circuit configuration to find the peak of the reflected wave, thereby making it possible to accurately measure the distance to the target. The purpose is

′! J That is, the distance measuring device of the present invention is aimed at the target object.
C Ultrasonic transmitting means for transmitting ultrasonic waves in a pulsed manner, etc. [1
an ultrasonic receiving means for receiving reflected waves from the wafer; a first ripple hold means for sampling the received signal at each vibration period and holding it as a first hold signal; .

a second ripple hold means that performs one non-pull at a predetermined time interval from the sample timing of the first number bold means and holds it as a second hold signal;
Comparison means for comparing the size of the hold signal and the second bold wave and emitting a reflected wave arrival signal when the latter becomes smaller than the previous one, and a comparison means for emitting a reflected wave arrival signal when the second bold wave is smaller than the previous one, and a comparison means for emitting a reflected wave arrival signal from the ultrasonic transmission. The apparatus is equipped with a means for measuring the time required to reach the target object and calculating the distance to the target object.

The present invention will be explained below with reference to illustrated embodiments.

Fig. 1, Fig. 2 tiWe have received an embodiment in which the device of the invention is mounted on the axle of a vehicle, and it is possible to detect the drop in air pressure of J and Reti-2 by knowing the distance between the center axle and the road surface. In other words, in the figure, a detector 1 is attached to the center shaft with the W attached to it. [) (Five ultra-high wave emitters and receivers in the national capital were installed (J) to emit ultrasonic waves towards the road surface and receive counter-waves.The above detection: (; 1 is connected to the separate protection noge 1p device 6゜2, and the arithmetic unit 2 outputs an ultrasonic transmission command signal to the detector 1, receives the arrival signal g of the foul wave, and transmits the ultrasonic wave 1p.
Detector 1 based on the period of 11.1 determined by 8.
The distance from the road surface to J is 11.

In other words, 4), if you change the 8th speed to V, is it tri? 'ah+iat required from transmission to reception of A wave is t = 2h
/v, and j'l'i 1li11h is I between 1 and k.
It is determined uniquely. Since the detector 1 is integrally fixed to the center shaft, the variation in the air pressure of the tire A7W appears as follows: - The variation in the recording distance 11. Therefore,
The calculation device 2 calculates the distance t11. If fi is constant (below the target), the tire air pressure will decrease (V!: the information will be n1).

FIG. 3 shows the electrical circuit of the detector 1. In the figure, 11 is an ultrasonic receiver, and 12 is an ultrasonic receiver.

Further, 101 is a transmitting circuit, 102 is a receiving circuit, 103 is a first ripple hold circuit, 104 is a second ripple hold circuit, and 105 is a comparison circuit.

Hereinafter, the operation of each circuit will be explained with reference to time charts 1 to 1 of FIG. 4. Note that the thin lines in FIG. 4 indicate expansion or contraction of the open reading axis.

The ultrasonic transmission command signal 2a (see Fig. 4 (1)) which is input from the arithmetic unit 2 (see Fig. 1) through the bottom of the terminal is the transmission timing signal of the diameter τ of the flip-flop 1 knob 101△, 101B composed of gates. 1a (See Figure 4 (3)) Howl. The timing signal 1a is synchronized with the rise of a reference pulse 111 (see FIG. 4 (2)) output from the oscillation circuit 101C. Then, the reference pulse 1b is frequency-divided by counters 101J) and 101E (
The transmission confirmation signal IC (see Fig. 4 (4)) at a predetermined frequency is sent to the transmitter 11 in synchronization with the rise of the open signal ia.
will be sent to. Excitation No. 45 1c is D type flip-71]
Constant 11 until the terminal connected to 1 knob 101F becomes anti-Iph
．． It is output in a pulsed manner for a period of 7 t1, and the signal F'7
1'-1j21 output γ11.1 is output by the output confirmation signal 1Jl (Fig. 4 (
16)) is output to the arithmetic unit 2 via the terminal below.

The ultrasonic waves emitted from the optical device 11 hit the road surface [(Ni1
(See figure) C inverse IJ-1 is input to the receiver '12. The receiver (1'i'fiT) passes through amplifiers 102A and 102B, which form one inverter.
The impedance is converted manually to the pin '7' 102C (signal C, j '1d, see Figure 4 (5) and (6)). Note that the received signal 1d is a constant voltage L output from the amplifier 106.
1: vfiI is at reference level and 1. Inferior.

Month 1 (1 is input to the analog switch 103△ constituting the first (non-build small circuit) 103 in the above A).

The signal 1 (1 is also input to the amplifier 107 forming a differentiating circuit, and the waveform shaping Asia'1 ('l/i is changed to the vibration period 1tJ of the red C to become 1 level, and the predetermined pulse is Rectangular pulse signal 1c (see Fig. 4 (7)) with width △(44'?
'l J,, ``J If 1ri1st term sea ('/''
-h 10, '3 is the resistance 1゜31-]
A sample signal 1f (see Fig. 4 (8)) is output, which overlaps the pulse width determined by 1 antl 103G.
Further, in synchronization with the falling edge of the signal 1e, the signals 1 to 1 to IO/IB that constitute the second ripple hold circuit 104 are
What about a 104C capacitor? The pulse width determined by 1'04D is set to 1'4J-Rinrl signal pg1a<Figure 4 (9
) 4) will appear.

S, No. 7, L1 switch 103A is upper 6 [T'!
J'Plui No. 5 1 ``Connect the C terminal of KA to fij manually.

L $1 NiJ, '), Uke4@ (Hj31 (I t
', L Each 'lk Motivation J! rJ K a3 I:J
The 10313 Amp 10313
, the first hold value 8'1h is output as C (
(See Figure 4 ("10)).

1. The first whole toy iN 'F: 'I h is output for a certain period of time △ (from the above Lingle Dengetsu 1 [J
11 < m No.'l g'', and was activated again.
It is held as the second hold signal 11 (see FIG. 4 (11)).

The first hold value 11) and the second hold signal 11 constitute a comparison circuit 105.
When compared with 5Δ, when the latter became more personable than the songwriter,
1” level of the peak detection signal 1j (Fig. 4 (12)
), (see (13)) are output. Signal 1. D by i
The type flip knob 105) 13 is turned to the filler 1, which causes the monostable multi-gamma veribrator 105G to generate a reflected wave arrival signal 11 (see FIG. 4 (15)) with a predetermined pulse width.
is sent to the control device 2 via the terminal below.

Note that the peak detection signal 1j is actually output as the received signal 1d has a peak as shown in FIG. Since it is short and constant, there is no problem in using it.

j: In the comparator 109, one C first small root toy word r'l l l, and the counter 10 i l- (
:) 9 marks 1: Rectifying and smoothing the output) (obtained constant current Jl)
f, V l+ are compared, and the signal "11) is the voltage vb
Above the level of!・In the case of (, L transmission 1 m (Fig. 11 < 1
(See <>) 1, the above-mentioned Noritsu Sono 1" Tsubu 105
The let of B is prohibited ("Reverse wave will be output on November 1st and 2j").

The performance q device 2 is the above-mentioned ultrasonic transmission confirmation im bow 1! Based on the time (2) from which the reflected wave arrival signal 1k reaches 1q, the distance to the road ff1iE is calculated. (L)
For example, in order to calculate L/10,000 times, determine the distance 1i11 between the detector 1 and the road surface E from the average value of the above calculation results, and then report the decrease to 11 yen and 7 air to the tie. !”

As described above, the distance measuring device of the present invention has an ultrasonic wave of 9.1
A first ripple hold circuit that samples and holds the wave at each vibration period, and a ripple hold circuit of the ripple hold circuit 2 which returns the hold value of the first ripple hold circuit after a predetermined time, are provided. By comparing (hold jf) of the pull hold circuit,
What '51'! 1 to another-%il place? -jna-), -do1
．． r<12. Detecting the peak of river waves 4. (Sfili:l)t/)(, J, Risarame(
The 41-circuit configuration in the cylinder makes it possible to accurately measure the distance to the target object.2 A) The device of Kimi Tomei is capable of detecting a decrease in the air pressure of the tie 11 as in the above embodiment. The best thing about using 5 for general distance measurement etc. is Moraro lυ.

J: If the level of the foul wave is constant at about [, 1 (D is in the above embodiment - (first bold signal '1110
Set up to check the level (10)
0 is not particularly required.

As described above, the distance measurement of the present invention '4+ n LL k'
Vertically split the target 'I! The bee of the foul wave of the shunted super wave
Detection of 7□ road 4.9 in the cylinder 7. Noh 6.5ゎ. . 1)
1゜

[Brief explanation of drawings]

Figures 1 and 2 show the inside of the device of the present invention.
+, - installation J' (air l of tie pulling 2) low dry detection line 41
-C of Example 4 is shown.
Figure 1. Figure 33 shows the electrical circuit diagram, Figure 4 shows the waveforms of each rod No. 13, and the waveforms of each rod No. 13 are shown. ...rl"l:311 detector 11...
Super high wave transmitting means 12...Super high wave transmitting means 103...First ring hold circuit 10'
l...Second Linsol hold circuit 1015.
...Comparison circuit 2...N IQG-';'Ding J', Q Fig. 1 Fig. 2

Claims (1)

[Claims] ``A supermultiplexing transmitter f stage that emits ultrasonic waves in pulses in one direction toward one object, a superconvex wave receiver that receives reflected waves from an object,'' an i means, and a receiving object stage. ] is its vibration period 1!IJ
fυ and set it as a first hold signal.
After a predetermined time delay from the sample timing (17,
a second sample and hold means for holding as a second hold signal;
Comparison means compares the magnitudes of the small wave signals, and when the latter becomes larger than the former, a reflected wave arrival signal is emitted. A distance measuring device comprising calculation means for measuring the time required to reach the destination and calculating the distance to the object.