JPS5880574A - Ultrasonic obstacle detecting device - Google Patents

Abstract

PURPOSE:To precisely detect an obstacle and to improve the reliability, by detecting leakage of a transmitted wave or existance of a direct wave and, when there is no detection, outputting alarm. CONSTITUTION:A tone burst signal is sent from an ultrasonic transmitter 5 to detecting circuits 9a, 9b through a transmission switch 4 during a timing signal T1 is at a ''0'' level. The output of the circuit 9a is applied to a comparator 15 through timing signals T2, T3 and the comparator 15 checks whether a direct wave exists or not. The sum of both outputs of the circuits 9a, 9b is supplied to the comparator 12 to find the distance data of the nearest obstacle detected by ultrasonic receivers 6a, 6b. When direct waves from the receiver 6b are not detected by a comparator 15 owing to a generated trouble, an FF13 is set up through the signal T3 and the distance data and the trouble are displayed on a display 20, improving the reliability of the titled device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an obstacle detection device that transmits ultrasonic waves and detects obstacles using reflected waves from the obstacles, and its purpose is to convert the transmission and delivery of waves. Ltransduce
The purpose is to provide something that can reliably check the operation of rJ.

Conventionally, in this Yuzu equipment, the operation check of the converter was done by
The operation was only checked at the start of the workday, and no measures were taken to prevent malfunctions during operation.
Currently, reliability as an obstacle detector suffers from the inability to detect failures during operation.

Therefore, the present invention detects the presence or absence of a transmitted wave leakage or direct wave before receiving a reflected wave from an obstacle, and generates an abnormality notification when a leakage of a previously transmitted wave or a direct wave is not detected. , which avoids the above-mentioned problems, and one embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

ill is an ultrasonic signal generator that outputs a tone burst signal of carrier frequency fO, (2) is a timing circuit,
Timing signals 'r1-'14 having a phase relationship as shown in FIGS. 2(a)-(d) are repeatedly output. (8a) (
8b) is a transmitting amplifier, (4) is a transmitting switch whose switching is instructed by the timing signal section, and TI is at logic level "O".
”, the tone burst signal is transmitted to one of the transmitting amplifiers (8
a), and when Tl is at the logic level "1", the tone burst signal is supplied to the other transmitting amplifier (81)), where it is switched every time opening τ0.

(6a) (5b) are ultrasonic transmitters connected to the outputs of transmitting amplifiers (8a) (8b); (6a) and (6b) are ultrasonic receivers; Wave amplifier, (8a)
(8b) is a tuning circuit tuned to the frequency fo, (9'
a) (9b) is a detection circuit, Ql) 141 is a timing signal T! Switching is instructed in the 1st. A second analog switch, with one end of each connected to a detection circuit (9a) (9b)
17) It is connected to the output, and the other ends are connected to each other, and both T2 are in the make state at logic level "1". (6)
is the first. A first comparator whose input is connected to the other end of the second analog switch o1 compares the level of the reflected wave from the obstacle with a reference level and outputs distance data to the obstacle.

01o4 are the 8th. A fourth analog switch, one end of which is connected to the output of the detection circuit (9a) (9b), and the other ends are connected to each other, Ts, T
When 4 is 1iaB lebel "l", it becomes a make state.

(c) is the 8th. A second comparator whose input is connected to the other end of the analog switch (b) of @4 compares the level of the direct wave from the ultrasonic transmitter (5a) (5b) with the reference level and directly The presence or absence of waves is detected, and if it is determined that there is a direct wave, the output is at a logic level of “1°°” for a certain period of time.
to be reversed. aQ is a gate circuit, and timing signal T3
and the second comparator ■output as input signals, extract only the detection of the second comparator aθ without a direct wave,
When there is no direct wave, the output level is inverted to "1" for a certain period of time. Qη is an R-S flip-flop, which uses the logical sum of the first comparator (b) output and the gate circuit Q0 output as a set signal via an OR gate (g), and outputs the inverter 01i.
The timing signal T is used as a reset signal. So is a distance indicator which uses the output O signal of the R-S flip-flop Q'1) as input data.

Hide: Because of this configuration, during the period when the timing signal Tl [Fig. 2 (a) is - ring level "O"]
The tone burst signal is transmitted from the ultrasonic transmitter (6a) [Fig. 2(e)] to the ultrasonic receiver 6sc).
The waves are received at (6b) [Fig. 2 (g), (h) and sent to the detection circuit (9a) via tuning circuits (8a) and (Ilb), respectively.
(9b). At this time, the timing signal Tz
(Fig. 2(b)") indicates the logic level "0" of the ultrasonic transmitter C3a)b' over time τ1 from time t1 when transmitting waves.
”, the first and second analog switches α (IQI) are in the break state, so the timing signal Ts (second
The output of the detection circuit (9a) [Fig. 2 (g)] is applied to the 20th) comparator (to) via the analog switch @8 whose switching is instructed by Fig. (C)].

Specifically, the presence or absence of a direct wave from the ultrasonic transmitter (61 Ling et al.) is first checked by the second comparator (to) during the period from time (1+τ2) to (h+τ20). Here, as shown in Figure 2-), the direct wave ■[
1. Therefore, the second comparator (to) output [second
The gate circuit section output [
FIG. 2(k)] shows the logic level "l" of the timing signal Ts.
” does not invert to logic level “L” within the period t1~
[R-S flip-flop af again at 1+τ1)
1" Fig. 2 (1)] is the timing signal "1'2 C2
Figure (b)] maintains the reset state. When time τl has elapsed from time [1], timing signal T2 is inverted to logic level "l" and R-S flip-flop Q
The reset state of η is released and the first. When both the second analog switches aQOv are in the make state and the detection circuit is connected to the input of the first comparator (2), both outputs of the tuning circuits (9a) and (9b) [Figure 2 (g)
(h) ) is applied to the output of the first comparator (2).
), distance data for the nearest obstacle among the detected obstacles can be obtained.

At time tz (tz = t + 10τ), the set R-S flip-flop (b) returns to the timing signal "l'r".
applies the reset burst signal (9a) and the output of (9b) is applied to the I comparator of lIl, and the reflected wave l
When the rising edge of [1 is detected, the first comparator (6
) The output [FIG. 2(i)] is inverted to logic level "1". The time t from time t until the output of the first comparator (2) is inverted to logic "1" is distance data according to the detection distance, and the R-S flip-flop a force is the output of the first comparator (2). ) is set at the time ([1+1)] when the output is inverted to logic level "1", and the output (2) [Figure 2 (
Z> J is inverted to logic level "l". Therefore, the distance indicator (4) converts this time t into a distance and displays the distance. Note that the timing signal T2 is inverted to the logic level "1", and the ultrasonic transmitter (6b) starts transmitting waves [FIG. 2(f)]. .

This time, the timing signal T3 is replaced by the timing signal T3.
4 (FIG. 2(d)) is inverted to the logic level "l", the output of the detection circuit (9b) [to the second comparator] is sent via the fourth analog switch (b).
(h)] is applied, and the presence or absence of a direct wave is checked as in the case of the leaving period t1 to t of the ultrasonic transmitter (5a). In the case of (Fig. 2), the direct wave I immediately after time t2
Since t□ is detected, the gate circuit cutout output does not invert to logic level "1". Similarly, the difference between the reflected waves by the first comparator (6) is 1. Detection of the rising edge of and setting and resetting of the R-S flip-flop are performed.

However, if a failure occurs on the way and the direct wave from the ultrasonic receiver (6b) cannot be detected by the second comparator (g) as in the case of time t4, the gate circuit output is Logic level “1” at the timing of signal T3
1, and the time (t4+
r2) is set to the R-S flip-flop. Therefore, when the input distance data is at time τ2, the distance display +a (1) converts it into a distance and displays it, and also executes a specific failure display to notify an abnormality. In this case, the specific failure display is not executed and only the distance converted is displayed. Note that the same applies when direct waves are not received by the ultrasonic receiver (6a).

In addition, in FIG. 2, τ4 represents the transmission time of the tone burst wave from the ultrasonic transmitter (5a) or (6b),
The time relationship with the timing signals 'r and -'r4 is τ4<
rz<(τ1+τ3)<τ1 In the above embodiment, the abnormality alarm is displayed on the distance display), but this is displayed on a separate display or sound source other than the distance display 4. It is also possible to configure the system to notify the abnormality by some means.

As described above, according to the ultrasonic obstacle detection device of the present invention, there is provided an obstacle detection means for detecting an obstacle by receiving the reflected waves of the transmitted ultrasonic waves from the obstacles; A monitor means for detecting the leakage of the pre-delivered wave or the presence of a direct wave before receiving the transmitted wave, and an abnormality alarm means for notifying the user when the monitor means determines that there is no leakage of the transmitted wave or direct wave. Therefore, even if the ultrasonic wave transmitting/receiving system fails during operation, it can be reliably detected, and the reliability of the apparatus can be greatly improved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a block diagram of an ultrasonic obstacle detection device, and FIG. 2 is a waveform diagram of the main part of FIG. 1. (1) Ultrasonic signal generator, (2) Timing circuit, (8a) (8b) Transmission amplifier, (4/Transmission switch, (5a) (6b) ...Ultrasonic transmitter,
(6a) (6b)...Ultrasonic receiver, (7a) (7b
)” Receiving amplifier, (8a) (8b)--tuning circuit, (9a) (9b)...detection circuit, αO...first analog switch, a-ya...second analog Switch, (2)...first comparator, (to)--eighth analog switch, α4...II4 analog switch, 4...second one comparator, (to)...
Gate circuit, ■...R-S flip-flop, (to)
... or game), (1...i, n data, ■...
Distance display agent Yoshihiro Morimoto

Claims (1)

[Scope of Claims] 1. Obstacle detection means for detecting an obstacle by receiving reflected waves of the transmitted ultrasonic waves from the obstacles, and detecting the leakage of the pre-delivered waves before receiving the reflected waves. Alternatively, an ultrasonic obstacle detection device is provided with a monitor means for detecting the presence or absence of a direct wave, and an abnormality alarm means for notifying when the monitor means determines that there is a leak in transmitted waves or that there is no direct wave. i. Claim 1, wherein the monitor means is constituted by an ultrasonic wave transmission/reception system separate from the obstacle detection means, and the abnormality alarm means is configured to display an abnormality through the obstacle detection means.
The ultrasonic obstacle detection device described in .