JPS5858411A - Distance displaying method for obstruction detector utilizing ultrasonic wave - Google Patents

Abstract

PURPOSE:To make a titled method convenient for detecting obstructions during retreating of an automobile or the like by producing continuous sounds when the distance from an ultrasonic transmitter and receiver up to the obstruction is within a specified value, changing the same to intermittent sounds when the distance exceeds the specified value and changing the periods of the intermittent sounds according to distances. CONSTITUTION:An ultrasonic wave transmitter and receiver 1 drives a transmitter 4 to generate ultrasonic waves. The ultrasonic waves are reflected by an obstruction 3 and are received in a receiver 5. The received output is applied to an ultrasonic wave receiver 2, which converts the same to the quantity of electricity corresponding to the distance up to the obstruction 3. The output of the receiver 2 is supplied to an oscillating circuit 13 and a comparator 14, both outputs whereof are fed through an AND circuit 15 and an amplifier 16 to operate a sounding body 17. Thus when the distance up to the obstruction is within a specified value, the sounds are continuous and when the distance exceeds the specified value, the sounds change to intermittent sounds. The periods of the intermittent sounds can be varied according to distances. It is also possible to change the timbres of the intermittent sounds or to display distances by lighting and flickering a lamp and changing the periods of the flickering.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for displaying the distance to an obstacle in an obstacle detecting device using ultrasonic waves.

Conventionally, there have been methods for displaying the distance to an obstacle in this type of device, such as by displaying it on a graph, on a cathode ray tube, by using a meter, or by using a tone of sound.
Graphs, cathode ray tubes, and meters do not allow you to recognize the presence or absence of obstacles and the distance to them unless you look closely at them, and tones represent continuous sound, which is audible and noise. It had the disadvantage that it was difficult to hear inside, and it was not possible to display a specific distance. There are also systems that use a buzzer or lamp to notify you if there is an obstacle within a certain distance, but they have the drawback that you cannot tell the distance to the obstacle unless you change the setting value.

The present invention improves these drawbacks.If the distance between the obstacle and the transmitter/receiver is within a certain value, the distance is notified by a continuous sound from the sounding body or by lighting a lamp, and if the distance exceeds the certain value, the distance is notified. The distance is displayed by changes in the period of the intermittent sound, changes in the flashing period of the lamp, or changes in the tone of the intermittent sound. This is particularly useful in detecting obstacles when reversing a vehicle or the like.

The present invention will be described below with reference to drawings of embodiments.

Figure 1 shows that if the distance from the transmitter/receiver (transmitter and receiver) to the obstacle is within a certain value, the sound from the sounding body will be a continuous sound, and if it exceeds a certain value, it will be an intermittent sound. 1 is a block diagram of an ultrasonic obstacle detection device that displays a distance by changing its period in accordance with the distance to the obstacle. Reference numeral 1 denotes an ultrasonic transmitter, which in this embodiment is comprised of a reference pulse generation circuit 6 and a transmission pulse generation circuit 7. The reference pulse generation circuit 6 is shown in FIG. 3A.
As shown in FIG. 2, a pulse having a width T2 is generated at a constant period T1, and this pulse is supplied to a transmission pulse generation circuit 7 to generate an ultrasonic signal pulse for driving a transmitter 4 made of a piezoelectric or electrostrictive element. ing. The signal width T3 (shown in B of FIG. 6) of the ultrasonic signal pulse generated by this transmission pulse generation circuit 7 is the output pulse width T2 of the reference pulse generation circuit B.
This is because in the embodiment, the signal pulse of this reference pulse generating circuit 6 is used as a processing signal of the ultrasonic receiver.

Ultrasonic waves are generated from a transmitter 4 connected to this transmission pulse generating circuit 7, reflected by an obstacle 6, and received by a receiver 5 made of a piezoelectric or electrostrictive element. The output waveform of this receiver 5 is shown in FIG. 6C. In this figure, T4
is the time corresponding to the propagation distance of the ultrasonic wave to the obstacle. Q in the figure is a waveform generated when a transmitter and a receiver are placed close to each other, or when the same vibrator (piezoelectric or electrostrictive element) is used as the transmitter and receiver. This is because the signal is directly transmitted from the transmitter to the receiver.

The ultrasonic wave received by the receiver 5 is converted into an electrical signal, which is applied to the ultrasonic receiver 2, and its output is converted into an electrical amount corresponding to the distance to the obstacle. An example of the configuration of this receiver 2 will be described below. The signal from the receiver 5 is amplified to a predetermined magnitude by an amplifier circuit 8, and then extracted by a detection circuit 9 and connected to a flip-flop circuit 11 through a delay circuit 10. This delay circuit 1
The purpose of passing 0 is to distinguish between short ultrasonic noise and signal components. D in FIG. 3 shows the output of the delay circuit 10. When compared with Figure A, the portion in front of T5 is removed because it has passed through the delay circuit 10. When this output and the signal from the reference pulse generation circuit 6 are connected to the inputs of the flip-flop circuit (ie, SE, /) and reset terminals, one of the outputs becomes 1 due to the reflected signal from the obstacle, and the signal from the reference pulse generation circuit B The signal becomes 0. This is shown in Figure 6E.

If this signal is passed through an inverting circuit, the result will be as shown in FIG. 6F. This signal (signal E or F shown in Fig. 6) is transferred to the integrator circuit 1.
1, the signal is converted into an electrical quantity such as resistance, voltage, or current according to the width of the signal. When the distance between the transmitter and the receiver changes, the pulse width of the flip-flop circuit 11 changes, so the amount of electricity that is the output of the receiver 2 changes (for example, as the distance increases, the amount of electricity changes). (or vice versa).

The output of this receiver 2 is supplied to an oscillation circuit 16 and a comparison circuit 14. The oscillation frequency of the oscillation circuit 13 changes depending on the amount of electricity of the human-powered receiver, and when the oscillation frequency is made into an intermittent sound, the oscillation frequency is a frequency that can be heard (for example, 0.2 to 5 H).
(about z). This circuit becomes a voltage frequency conversion circuit when the input is a voltage. The comparator circuit 14 is a circuit whose output becomes 1 when the magnitude of the electrical signal output from the receiver 2 becomes larger (or smaller) than a certain value. This allows the output to be set to 1 when the distance from the transmitter/receiver to the obstacle exceeds a certain value.

The output of the comparator circuit 14 and the output of the oscillation circuit 13 are inputted into an OR circuit 15, and the logical sum becomes an output, which is amplified to a required level by an amplifier 16 to operate a sounding element 17. In this case, the input voltage to the oscillation circuit 13 is equal to or higher than a certain value (
If a circuit whose output is 1 without transmitting a signal when the signal is reached (or less) is used, the comparator circuit 14 and the OR circuit 15 are unnecessary. The sounding body 17 is a device such as a buzzer or a speaker that emits sound using an electric signal (however, if a normal speaker is used, a separate oscillator for the sound frequency is required).

With this circuit, if the distance from the transmitter/receiver to the obstacle is within a certain value, the output of the receiver 2 will be within (or above) a certain value, so the output of the comparator circuit 14 will be 1, which will cause the sounding element to The sound from is a continuous sound. Furthermore, if the distance from the transmitter/receiver to the obstacle exceeds a certain value, the oscillation circuit 1
6 works and the oscillation frequency changes according to the distance.Therefore, the sound from the sounding body 17 becomes an intermittent sound, and the period of the intermittent sound changes depending on the distance. Therefore, as the distance becomes longer, the period of the intermittent sound can also be lengthened. (This can also be reversed.) Next, if a lamp is connected in place of the sounding body 17 or together with the sounding body, the lamp will light up if the distance from the transmitter/receiver to the obstacle is within a certain value. If the distance is exceeded, the lamp will start blinking, and the blinking cycle will change depending on the distance to the obstacle; if the distance from the transmitter/receiver to the obstacle is longer, the lamp's blinking cycle will also become longer. .

Figure 2 shows how the distance is displayed.If the distance from the transmitter/receiver to the obstacle is within a certain value, it is a continuous sound, and if it exceeds a certain value, it becomes an intermittent sound, and the tone changes depending on the distance. FIG. 1 is a block diagram of an embodiment of an obstacle detection device using ultrasonic waves, which is a sound. Since parts 1 to 12 in FIG. 2 are exactly the same as those in FIG. 1, the output of the receiver 2 is an amount of electricity corresponding to the distance from the transmitter/receiver to the obstacle. For the sake of explanation, in the embodiment, it is assumed that the output of the receiver 2 is a voltage, and that this voltage increases as the distance to the obstacle increases. Other cases can basically be processed in the same way.

18 is a comparison circuit whose output becomes 1 when the output voltage of the receiver 2 exceeds a certain value. 19 is the audio frequency of tU voltage frequency conversion circuit 111? ° is an oscillation circuit, and the oscillation station θ is set so that the number changes depending on the human force pressure. Since 2o is an unstable multivibrator for generating intermittent sound, its cycle is set to about 0.2 to 2 seconds. These 2
Add to the AND circuit of 1.

22 is an inverting circuit, and when the input voltage of the 18 comparison circuits is below a certain value, the output of the inverting circuit 22 becomes 1. 23 is a hearing frequency oscillation circuit, which oscillates at a constant frequency. 24 is an AND circuit, ν), this human power has a second
Connect these as shown in the figure. Reference numeral 25 denotes an OR circuit, which inputs the output of the AND circuit 21 and the output of the AND circuit 24. Reference numeral 27 denotes a comparison circuit, which is set to a voltage 7 that is sufficiently larger than the comparison voltage (reference voltage) of the comparison circuit 18. This voltage ultimately corresponds to the distance from the transmitter/receiver to the obstacle, so it is set to a voltage corresponding to the maximum value of the distance to be detected. Comparison circuit 2
The output of 7 is set so that it becomes 1 when the input voltage is smaller than a certain value, and 0 when it is larger. 26 is an AND circuit, and the output of the OR circuit 25 and the output of the comparison circuit 27 are manually operated. 2nd is an amplifier and 29 is a sounding body, but in this case a speaker is used.

According to these circuit configurations, if the distance from the transmitter/receiver to the obstacle is within a certain value, the output voltage of the receiver 2 will be smaller than the set voltage of the comparison circuit 18, so its output will be 0.
The output of the AND circuit 21 also becomes 0. However, since the output of the inversion circuit 22 becomes 1, the output pulse of the audible j# wave number oscillation circuit 23 appears in the output of the AND circuit 24, and
A similar output is also output from the logical sum circuit of No.5. 27
The output of the comparator circuit is 1 in this case, so 26
An audible frequency signal also comes out from the output of the AND circuit, which is amplified by the amplifier 28 and drives the sounding element 29. Therefore, in this case, it is a continuous sound.

Next, when the distance from the transmitter/receiver to the obstacle becomes longer than a certain value, the output voltage of the receiver 2 becomes larger than the comparison voltage of the comparison circuit 18, and its output becomes 1. At this time, 1
The output of the audio frequency oscillation circuit 9 changes depending on the distance from the transmitter/receiver to the obstacle, and is added to the AND circuit 21 along with the output of the unstable multivibrator 20, so the output becomes a signal source of an intermittent tone whose tone corresponds to the distance from the transmitter/receiver to the obstacle. 2
The output of the AND circuit No. 4 becomes O since the output of the inversion circuit No. 22 is 0. In this case, the output of the comparison circuit 27 is 1.
Therefore, this intermittent sound signal appears in the output of the AND circuit 26, is amplified to a predetermined magnitude by the amplifier 28, and the sound generator 29 emits this intermittent sound.

Furthermore, as the distance from the transmitter/receiver to the obstacle increases, the output voltage of the receiver 2 increases, and when the output of the comparison circuit 27 becomes 0, no sound is emitted from the sounding body. This circuit is used when it is necessary to stop the sound from the sounding body when the distance of an obstacle from the transmitter/receiver exceeds a certain value. If this is not necessary, the output of the comparator circuit 27 is always set to 1.

In FIG. 3, the horizontal axis of each waveform diagram represents time, and the vertical axis represents the magnitude or presence or absence of a signal.

According to the distance display method of the present invention, if the distance of the obstacle from the transmitter/receiver is within a certain value, the presence of the obstacle is notified by a continuous sound or lighting of a lamp, so that it can be easily perceived, and the distance is within a certain value. If the distance is exceeded, the sound changes to an intermittent sound or a flashing lamp, and the timbre of the intermittent sound changes depending on the distance, or as the distance increases, the period of the intermittent sound or the period of the lamp flashing becomes longer.
The distance to an obstacle can be known very easily, and the obstacle can be known in advance. Furthermore, if the distance from the transmitter/receiver to the obstacle is within a certain value, a continuous sound or a lamp will be lit, so it can be easily distinguished from the intermittent sound or flashing lamp that is a preliminary warning. This is particularly useful when detecting obstacles when reversing a vehicle, such as when the driver has to look at something else, or when the obstacle cannot be seen.

In this description, the distance from the transmitter/receiver to the obstacle is strictly the distance from the transmitter to the receiver via the obstacle, and the lamp includes a light emitting diode and the like.

[Brief explanation of the drawing]

FIGS. 1 and 2 show an example of an embodiment using the distance display method of the ultrasonic obstacle detection device of the present invention. FIG. 6 is a waveform diagram of each part. 1 is an ultrasonic transmitter, 2 is an ultrasonic receiver, 6 is an obstacle, 4
is a transmitter, 5 is a receiver, 6 is a reference pulse generation circuit, 7 is a transmission pulse generation circuit, 8 is an amplifier circuit, 9 is a detection circuit, 1
0 is a delay circuit, 11 is a flip circuit, 12 is an integration circuit, 16 is an oscillation circuit, 14 is a comparison circuit, 15 is an OR circuit, 16 is an amplifier, 17 is a sounding body, 18 is a comparison circuit, 19 is 1fIa! ! ! Frequency oscillation circuit, 20 is an astable multi-pipe, lator, 21 is an AND circuit, 22 is an inversion circuit, 23 is a m-frequency oscillation circuit, 24 is an AND circuit,
25 is an OR circuit, 26 is an AND circuit, 27 is a comparison circuit, 28 is an amplifier, and 29 is a sound generator. Patent applicant Fujio Nakamae

Claims (6)

[Claims] (1) Distance display of an obstacle detection device that generates ultrasonic waves from a transmitter, reflects them off an obstacle, receives them by a receiver, detects the obstacle, and displays the distance as a sound from a sounding body. In this method, if the distance from the transmitter/receiver to the obstacle is within a certain value, it becomes a continuous sound, and if it exceeds a certain value, it becomes an intermittent sound, and the period of the intermittent sound corresponds to the distance from the transmitter/receiver to the obstacle. The distance display method is characterized in that the period of the intermittent sound increases as the distance increases. (2) Distance display of an obstacle detection device that generates ultrasonic waves from a transmitter and reflects them off an obstacle, detects the obstacle by receiving it with a receiver, and displays the distance as a sound from a sounding body. In this method, if the distance from the transmitter/receiver to the obstacle is within a certain value, it becomes a continuous sound, and if it exceeds a certain value, it becomes an intermittent sound, and the frequency of the intermittent sound changes depending on the distance from the transmitter/receiver to the obstacle. A distance display method characterized in that it changes correspondingly. (3) Distance display method for an obstacle detection device that generates ultrasonic waves from a transmitter, reflects them off an obstacle, receives them by a receiver, detects the obstacle, and displays the distance by flashing a lamp. In this case, if the distance from the transmitter/receiver to the obstacle is within a certain value, the lamp will not light up, and if it exceeds a certain value, the lamp will blink, and the period of the blinking will change depending on the distance from the transmitter/receiver to the obstacle. A distance display method characterized by increasing the distance as the distance increases. (4) The distance display method according to claim (1), in which the same transducer is used as an ultrasonic transmitter and receiver. (5) The distance display method according to claim (2), wherein the same transducer is used as an ultrasonic transmitter and receiver. (6) The distance display method according to claim (3), wherein the same transducer is used as both an ultrasonic transmitter and a receiver.