JPS5892877A - Ultrasonic distance measuring device - Google Patents

Abstract

PURPOSE:To improve the precision of distance measurement, by incorporating preliminarily synchronized clock devices in respective devices in the transmission side and the reception side and synchronizing the ultrasonic radiation time and the count start time with each other through these clock devices by radio waves or the like. CONSTITUTION:When a square pulse is outputted from a pulse generator 10 in a transmitting device 1, radio waves B subjected to frequency modulation are radiated during a duration t2 of this pulse, and ultrasonic waves A are radiated from a transmitter 4 by the pulse which is generated from a delay pulse generator 16 after the time t2. In a receiving device 2, radio waves B are received, and a clear signal is generated from a time signal generating circuit 21 on a basis of these radio waves. This signal is generated in accordance with the trailing edge of the pulse from a generator 10 and is given to a counter 23 to determine the start time of counting. The time of generation of the clear signal coincides with the time when ultrasonic waves A are radiated from the transmitter 4 in the transmission side. Thus, counting is started simultaneously with the start of propagation of ultrasonic waves, and the precision of distance measurement is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an ultrasonic distance measuring device that measures the distance between 1III names by emitting ultrasonic waves between a transmitting device and a receiving device that have a built-in clock device synchronized in advance. In ultrasonic distance measurement, when emitting ultrasonic waves, radio waves, etc. are sent from the transmitting device to the receiving device in advance to synchronize the operations of both devices, measure the propagation time of the ultrasonic waves, and measure the distance. Regarding equipment.

One possible method for measuring the distance is to propagate an ultrasonic wave over that distance, and then measure the distance by multiplying the time required for propagation by the propagation speed of the ultrasonic wave. In order to realize such a distance measurement method, a device that emits ultrasonic waves is placed at one end of the above distance, a device that receives the emitted ultrasonic waves is placed at the other end, and the ultrasonic wave between the two devices is placed. The device is configured to measure the propagation time of sound waves. However, in order to measure the propagation time of ultrasonic waves in a device that receives ultrasonic waves, the time point at which the ultrasonic waves are emitted must be known. In other words, the device that receives the ultrasound starts counting time at the same time as the ultrasound is emitted, and ends counting when the ultrasound arrives, thereby measuring the propagation time of the ultrasound over the short distance being measured. It is something to do.

However, as a practical matter, it is technically extremely difficult to know how to know when the ultrasonic waves are being emitted on the side receiving the ultrasonic waves.

The present inventor has devised the present invention in order to effectively solve the above problem, and an object of the present invention is to transmit radio waves, etc., between a transmitting device and a receiving device, each of which has a built-in clock device. Leverage ultrasonic distance measurement: Propagates a sound wave, synchronizes both devices using radio waves, etc., notifies the receiving side of the ultrasonic emission point, measures the propagation time of the ultrasonic wave, and measures the distance between the two devices. The goal is to provide equipment.

An object of the present invention is to enable accurate measurement of the propagation time of ultrasonic waves with the above-described configuration. The purpose of this is to have a built-in unique clock that is synchronized in advance in each of the transmitting device and the receiving device, so that even if radio waves, etc. do not reach the receiving device well (even if radio waves etc. The goal is to be able to roughly measure the propagation time of ultrasonic waves by the action of a synchronized clock of a receiving device, and use this to measure the distance.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows the configuration of a distance measuring device according to the present invention, where 1 is a transmitting device and 2 is a receiving device. , the transmitting device 1, and the receiving device 2 are each in a stationary state at a predetermined interval 1.
1. ), the transmitting device 1 consists of a transmitting circuit 3, an ultrasonic transmitter 4 equipped with it, and a transmitting antenna 5 for synchronization timing, while the receiving device 2 consists of a receiving circuit 6 and equipped with it. It consists of an ultrasonic receiver 7 and a receiving antenna 8 for synchronization timing.

Through this, in principle, the operations of the transmitting device 1 and the receiving device 2 can be synchronized, and the transmitting device 1:11, the transmitter 4 of the receiving device 2 and the Both devices 1,
It is possible to measure the distance t of 2.

In the above, the transmitting circuit 3 and the receiving circuit 6 have a built-in clock device, and the receiving circuit 6 is clocked by the radio wave B.
The radio wave B is used to synchronize the operations of devices 1 and 2 (it functions as a timing signal when emitting ultrasonic waves).

In FIG. 2, the transmitting circuit 1 includes an oscillator 9a for generating ultrasonic waves A and a carrier wave oscillator 9b for generating radio waves B. Each oscillator 9a.

The oscillation output of 9b is processed as follows based on the operation of the pulse generator 10 which outputs a pulse signal used as a time signal, and the antenna 5 emits radio waves B and the transmitter 4 emits ultrasonic waves Av. It works like this.

That is, as shown in FIG. 4, the pulse generator 10 having a clock function generates a pulse with a pulse width t2 at a constant repetition period t1.
The modulator 12 modulates the output of the ultrasonic oscillator 9a by the rectangular pulse output, and the output 13 of the development oscillator 9a at a time t2 during which the pulse 11 lasts is sent to the frequency modulator 14. A frequency modulator 14 combines the pulsed output 13 from the modulator 12 and the carrier wave oscillator 9.
b, and frequency modulates the carrier wave during the above t2.

The frequency-modulated carrier wave 15 is then emitted from the transmitting antenna 5 to the outside as a radio wave B.

On the other hand, the output 11 of the pulse generator 10 is also sent to a delayed pulse generator 16, which generates another rectangular pulse 17 with a pulse width t3 corresponding to the falling edge of the pulse 11. , outputs this. The pulse 17 is input to a modulator 18 at the next stage, and the modulator 18 modulates the output from the oscillator 9a with the pulse 17. As a result, the output 19 of the oscillator 9a during time t3 is transmitted to the transmitter 4.
A pulsed ultrasonic wave A is sent from the transmitter 4.

This series of operations generates a rectangular pulse 1 from the pulse generator 10.
7, which is performed every time 1 is output.

In the above, the value of 11 is, for example, lQmsec, or t2
The value of is set to about 600 to 1000100O, for example.

The ultrasonic frequency is, for example, 23 KHz, and the carrier wave frequency is, for example, 76 MH2.

Next, the configuration of the receiving circuit 6 will be explained based on FIG. 3. In the receiving circuit 6, the radio wave B received by the receiving antenna 8 is input to the FM receiving device 20, where the signal is processed and a synchronization signal is obtained. This synchronization signal is input to the time signal generation circuit 21, and the time signal generation circuit 21'r) is corrected by the IJ girder. 24, a display 25, etc., and is configured to send a signal for synchronization to each circuit.

Furthermore, there is an incoming super γ between the receiver 7 and the first-come-first-served priority determination circuit 22.
A circuit 26 is provided for amplifying and shaping the electrical signal generated from the single wave.

In the above, the FM receiving device 20 receives an incoming electric signal.
The FM receiver 20 has built-in circuits for amplifying B, converting the frequency, amplifying the intermediate frequency, detecting the signal, and amplifying the low frequency.
A signal such as 27 as shown in FIG. 4 is extracted from 7J as the synchronization signal.

The time signal generating circuit 21 is a circuit that normally performs free-running oscillation, and has a clock function in the receiving circuit 6, and sends a counter clock signal 28 to the counter 23, and also sends a counter clock signal 28 to the counter 23. The circuit is configured to generate a clear signal and a latch signal at time intervals of , and the clock signal, clear signal, and latch signal serve as a time base in the receiving circuit 6. Further, the operation of the time signal generating circuit 21 is synchronized with the pulse signal 11 which functions as a clock within the transmitting circuit 3 by a signal 27 sent from the transmitting side.
As shown in FIGS. (h), (i), and (j), the clear signal 29 and the latch signal 30 are corrected and generated in a constant time relationship with the signal 27. When synchronization is established in this manner, the clear signal 29 corresponds to the trailing edge of the signal 27, and the latch signal 30 corresponds to the leading edge of the signal 27, respectively.

The counter 23 is, for example, a 2-digit decimal or 3-digit decimal up counter, and has an input for a clock signal and an input for a clear signal.After inputting the clear signal 29, the clock signal 28 is input. The number of pulses of the clock signal 2'8 is counted until the first ultrasonic wave arrives.

The memory device 24 and the display device 25 operate based on the latch signal 30, and store and display the contents of the counter 24.

The operation of the distance measuring device having the above configuration will be explained.

In the transmitting device 1, the square pulse 11 is transmitted to the pulse generator 1.
When output from 0, this square pulse 11 is used as a time signal, and the above-mentioned (
The antenna 5 emits a wave number modulated radio wave B during the duration t2 of the rectangular pulse 11, and the ultrasonic wave A is emitted from the transmitter 4 by the pulse 17 generated from the delayed pulse generator 16 after t2. Ru.

On the other hand, the receiving device 2 receives the above-mentioned radio wave BY aerial signal 8, extracts the signal 271 yen from the radio wave B, and uses the signal 27 as a reference to send the clear signal 29 from the time signal generation circuit 21.
A latch signal 30 is generated.

Therefore, the clear signal 29 corresponds to the signal 27.
It occurs corresponding to the trailing edge, ie the trailing edge of the square pulse 11. The function of the clear signal 29 is given to the a1 counter 23 and determines the start time 7 of counting.On the other hand, when the clear signal 29 is generated, the ultrasonic wave A is transmitted from the transmitter 4 on the transmitting side.
Since this corresponds to the time when the ultrasonic wave is emitted, counting starts at the same time as the ultrasonic wave starts propagating. Fourth
31a in FIG. m is the time when the counter 230 starts counting.

The next emitted ultrasonic wave A arrives at the receiving device 2 after a certain period of time, but in reality it is reflected by obstacles etc. and some ultrasonic waves As + 'k + A'3 are received by the receiving device 2. It arrives at vessel 7. Therefore, in the receiving device 2, the first-come-first-served priority determination circuit 22 extracts the pulse output hole' related to the first ultrasonic AC which is a direct wave, and the counter 2
3, the counter 230 completes the counting operation with the destination signal. In this way, the propagation time of the ultrasonic wave A that propagated between the transmitting device 1 and the receiving device 2 is measured by the counting operation 31 of the counter 23.

When the radio wave B is not received by the antenna 8 of the receiving device 2, the time base of the clear signal etc. is configured to be generated automatically by predicting the time when the ultrasonic wave A will be emitted. Similarly to the above, the receiving device 2 can approximately measure the propagation time of the ultrasonic wave A.

In the above embodiment, radio waves are used as a means of notifying the receiving side when ultrasonic waves are being emitted, but the method is not limited to this, and other methods such as light may also be used. It is also possible to use Also a transmitting device,
It goes without saying that the circuit configuration of the receiving device is not limited to the above embodiment, and the design can be changed without departing from the gist of the invention.

As is clear from the above description, according to the present invention, the transmitting side,
Each device on the receiving side has a pre-synchronized clock 1 built-in device, and synchronization between the ultrasonic emission and the start of counting is done via radio waves, etc. 2, so distance measurement is possible. In addition, even if synchronization is not achieved by radio waves or the like, the distance can be approximately measured by synchronizing with the clock device in advance.

[Brief explanation of drawings]

The drawings show a second embodiment of the present invention, FIG. 1 is a block diagram of an ultrasonic distance measuring device according to the present invention, and FIG. 2 is a circuit diagram of a transmitting device. 3 is a block diagram showing the circuit configuration of the receiver, and FIG. 4 is a diagram of various waveforms for explaining the operation. In the drawing, 1 is a transmitting device, 2 is a receiving device, 4 is a transmitter,
5 is a transmitting antenna, 7 is a receiver, 8 is a receiving antenna, A is an ultrasonic wave, B is a radio wave, etc. Applicant: Dentan Co., Ltd. Agent Benkyu 1 Part 2 1) Co., Ltd.

Claims (1)

[Claims] Showa 7'? - An ultrasonic device that propagates ultrasonic waves between a transmitting device that sends waves and a receiving device that receives ultrasonic waves, and measures the distance between the two devices by measuring the propagation time of the ultrasonic waves at the receiving device. In the sonic distance measuring device, each of the transmitting device and the receiving device is provided with a clock device 7 that determines the operation of each device, and the transmitting device is provided with a device that sends electromagnetic waves including a signal related to the ultrasonic emission, The device receives the electromagnetic wave 7 and extracts a signal related to the ultrasonic emission, and uses this signal to operate the clock device of the receiving device.
An ultrasonic distance measuring device characterized in that the operation of one device can be synchronized.