JPS6063482A - Trouble detecting circuit of ultrasonic obstacle detector - Google Patents

Abstract

PURPOSE:To improve the reliability by providing a trouble detecting circuit to detect surely troubles of a receiver. CONSTITUTION:When a receiver 4 is faulty, an output S23 of a diagnostic comparing means 22 is held logical ''0'' because resonance oscillation is not generated for impression of a diagnostic pulse. When the diagnosis of the receiver 4 is terminated, the diagnosis of a receiver 5 is performed continuously. While receivers 4 and 5 are operated normally, the diagnostic comparing means 23 outputs a pulse signal twice during one period T1. A trouble discriminating means 24 counts this pulse signal; and the output is held logical ''0'' if the counted value during one period T1 is 2; but the number of pulses outputted from the diagnostic comparing means 23 is <=1 because of troubles of one of receivers 4 and 5 at least, an output S24 is set to logical ''1''. Consequently, for example, a transistor 25b of a trouble display part 25 is turned on to light a lamp 25a, thereby indicating troubles of the receiver 5 or the like.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a failure detection circuit for an ultrasonic obstacle detection device that detects objects by transmitting and receiving ultrasonic waves, and in particular to a failure detection circuit for an ultrasonic obstacle detection device that detects an object by transmitting and receiving ultrasonic waves. This invention relates to a failure detection circuit.

[Prior art]

It is applied to ultrasonic obstacle detection devices, automatic doors, and automobile rear monitoring devices.The principle is that ultrasonic waves of very short duration are emitted and the reflected waves from obstacles are received. The distance CIL to the obstacle is calculated based on the elapsed time from the time the sound wave is emitted to the time the reflected wave is received. The monitoring device displays information such as a-reports.

FIG. 1 is a schematic configuration diagram showing such a conventional ultrasonic obstacle detection device, and FIGS. 2(a) to (f) are timing charts explaining its operation. This conventional ultrasonic obstacle detection device will be explained based on FIG.

In FIG. 1, (1) is a reference time generating section (
2) is an ultrasonic wave transmitter (hereinafter referred to as a wave transmitter) consisting of a ceramic vibrator, etc.; It is a transmitter drive unit that generates sound waves, and its frequency is, for example, 4.
0 KHz square wave oscillator (3a), AND gate (
3b), driver (3C), and goo)
(3b) takes the AND of the output of the rectangular wave oscillator (3a) and the output ($1) of the reference time generator (1), and amplifies the output of this anti-game (3b) with the driver (3c). do.

Therefore, the output (S3) of the transmitter Mll+ section (3) causes the transmitter (2) to emit the emitted wave (2a). (
41s (Required for ultrasonic receivers (hereinafter referred to as receivers) consisting of ceramic transducers from each of the 51 companies, obstacles (6)
In order to widen the detection range a and α, two resonators are provided in this way, and a resonance force is generated by receiving the reflected wave (6a) due to (6). (7) and (8) are both resonant parts, and the coil # (7a)t or (8a), the capacitor C7b)-1, or (8b), the transfer device (4
1, (51), the receiver (41, (5
) has the function of modifying the resonance characteristics of

That is, the receivers (41, (5) have very sharp resonance characteristics and can only receive ultrasonic waves with frequencies near the resonance frequency, and the transmitter drive unit (3) and the transmitter (2) , receiver (
4).

(5) Depending on manufacturing variations, reflected waves (6
Since the frequency of a) and the resonance frequency of the transfer devices (41, (51) are different, the transfer devices (4) and (5) are reflected waves (6
(a) becomes difficult to receive, so the resonance characteristics are modified so that the frequency band in which the receiver (41, (5)) can resonate is expanded. (9) (41,
(Adder unit that adds each output of 51, (10) is an adder unit (
(9) is a receiving amplifying section that amplifies the output of the receiving wave amplifying section (11) is a receiving amplifying section (12) that integrates the output of the receiving wave amplifying section (l);
is a wave receiving comparing unit that compares the output of the wave receiving integrating unit (11) with a predetermined reference value vrl. (13) I'i distance measuring section, which measures the distance from the output (812) of the wave receiving comparison section (12) and the output (81) of the reference time generation section [11] to the obstacle (6). . This distance measuring section (13) has a tri distance signal generation timer (13a) and a 7-lip 70-tub (hereinafter F, F
) (13b), and the distance signal generation timer (13a) receives the output (Sl) of the reference time generator (1), and the distance signal generation timer (13a) receives the output (Sl) of the reference time generator (1), and starts from the rising time of this output (Sl) for a predetermined time T3 The interval output (S13a) is set to logic "1". F, F, (13b) is the data input terminal D1
It has a clock pulse input terminal CK, an output terminal Q, and a reset terminal R, and the output (S13a) of the distance signal generation timer (13a) is connected to the data input terminal, and the receiving comparison unit (12) is connected to the clock pulse input terminal CK. Output (812)
However, the output (Sl) of the reference time generator (11) is connected to the reset terminal RVc, and the state of the input signal at the data input terminal at that time is latched by the rising edge of the input signal at the clock pulse input terminal CK. and set it to output terminal Q.
The rising edge of the input signal at the reset terminal R sets the output at the output terminal Q to logic "0". (14) is the obstacle display section, lamp (14a), ) transistor (
1, 4b), the register (14c) inputs the output of the distance measuring section (13), and the lamp (14a) lights up when the output is logical [moon].

Conventional ultrasonic obstacle detection devices have 4? W
(see Fig. 1), and detects obstacles by operating as follows (see Fig. 2).

The transmitter (2) is attached to the transmitter pawl (3) as shown in Figure 2 (b).
It is driven by the output waveform shown in (S3), and the frequency is 40.
■The period of the ultrasound for goods 2 is T! (For example, 100m5ec
), fire for a time T2 (for example, 1 m5ec). The emitted ultrasonic wave (2a) is reflected by the obstacle (6) and becomes a reflected wave (6a), which is transmitted to the receiver (41,
(5), and the outputs of the receivers (41, +51) are added in an adder (9) to produce a signal as shown in (S9) in FIG. 2(C).

The output (S9) of this adder (9) is the receiving amplifier (10).
) and integrated by the reception integrating section (11), the output (311) shown in FIG. ) at the predetermined reference value V
rl, a pulse-like output (
S12) occurs. By measuring the time difference between the start-up time of this output (812) and the start-up time of the output (Sl) of the reference time generator (11), which is the ultrasonic emission time, the distance to the obstacle (6) can be determined. can be easily known, but here, if the reflected wave (6a) is received during the time T3 corresponding to the predetermined distance to the obstacle (6) after the ultrasonic wave is emitted, then within this distance The lamp (14a) is turned on when the obstacle (6) is detected.That is, after the ultrasonic wave is emitted, the distance signal timer (13a) is turned on during the time T3.
), the data input terminals F, F, (13b) are set to logic "1", and the transfer comparison unit (12) generated by receiving the reflected wave (6a) during time T3. ) by the rising edge of the output (812), F, F.

Since the logic "1" is set at the output terminal Q of (13a), the lamp (14a) will be lit. After this lamp (14a) is turned on, it turns F and F at the rising edge of the output (Sl) of the reference time generator +11, which occurs at a period TI.

(131>) is reset, the light goes out temporarily,
It lights up again when the reflected wave (6a) of the next cycle is received,
This process is repeated from now on, but since the time when the lights are off is much shorter than the time when they are on, it appears to the human eye that the lights are always on. Note that if the obstacle (6) does not exist within the predetermined distance, the lamp (14)
a) does not light up at all.

In this way, it is possible to detect whether or not the obstacle (6) exists within a predetermined distance and display it with the lamp (14a).

Now, in such a conventional ultrasonic obstacle detection device, the transmitter (2) and the receiver +41, (51) are used for emitting and receiving ultrasonic waves, so they are directly connected to the outside air. It must be installed in a place where it can be touched. Therefore, it may become contaminated with foreign matter such as dust in the air, or freeze in cold weather, causing it to malfunction. Is the lamp not lighting up because (6) is not within the predetermined distance? Transmitter (2), receiver +4
1. (51) It is very inconvenient because it is impossible to distinguish whether the light does not turn on due to the above-mentioned malfunction or not.

[Summary of the invention]

The present invention has been made in order to eliminate the drawbacks of the prior art, and it is an object of the present invention to provide a failure detection circuit in which the device itself automatically detects deterioration or failure of a receiver. In other words, the state of the receiver is determined by applying a diagnostic pulse for diagnosing a failure to the receiver and checking the response signal of the receiver to this pulse.

Next, embodiments of the present invention will be described in detail with reference to the drawings, in which the same elements are designated by the same reference numerals in each drawing.

[Embodiments of the invention]

The third part is a schematic diagram showing the first embodiment of the present invention. (15) is the reference time generator (output (Sl) of 11)
The diagnostic pulse applying means (16) is also a diagnostic pulse applying means for the wave receiver (5), and each diagnostic pulse applying means (15)
), (16) each output (815), (816)
are (815) in Figure 4(e) and (g), respectively.
As shown in (816), each time T 4 starts from the rising time 'ro of the output (Sl) of the reference time generator (1).
+ Outputs a pulse after TK.

(17) and (18) are diagnostic pulse application means (15)
, after the output (815) of (16) and (816) start up, (817) of FIG. 4(e), (i),
As shown in (st8), there is a resonance characteristic switching means that switches the characteristics of the resonant section for a predetermined period of time and separates the receivers (4) and (5). This is accompanied by a receiver (4
When the diagnostic pulse is applied to the diagnostic pulse application means (15) and (16) even if the
can be prevented from outputting the same signal as when it is normal.

When the characteristics of the resonant parts (7) and (8) are switched, or when the characteristics of the resonant parts (7) and (8) are switched,
If the diagnostic pulse is applied to the receivers (41, (5)), these receivers +41
, (Since normal resonant vibrations do not occur when 51 is dead, by examining the output of the receiver (41, (5), it is possible to distinguish between the normal state and the late state. (19) 11 received wave Vessel (4)
, (5), the output of the receiver on the side undergoing a failure diagnosis, that is, on the side to which a diagnostic pulse is applied by either the diagnostic pulse applying means (15) or (16). The switch section (19a) is a receiver selection means that selects the strength of the receivers (4) and (5) and inputs it to the addition section (9) so that the damage is input to the addition section (9). )
, (19b) and this switch part (19a), (1
9b) and a control section (19e) that controls f1. Switch part (19a).

(19b) normally remains open. Control unit (
19c) receives the output (Sl) of the reference time generator +11, and outputs the output (81) of the diagnostic pulse applying means (15) to the receiver (4) as shown in FIG.
5), the switch section (19b) is operated for approximately the same time as the time T11 during which the resonance characteristic switching means (17) is operating.
is controlled so that only the output of the receiver (4) is input to the adder (9), and the diagnostic pulse application means (16) inputs the output (816) to the receiver (5). After that, the switch part (x9a) is closed for a time almost the same as the time T6 during which the resonance characteristic switching means (18) is operating, and only the output of the receiver (5) is applied to the n2 part (9). control to input.

This allows for example - while diagnosing the force transfer device (4);
For example, if the ultrasonic noise generated externally is transmitted to the other receiver (
5) receives the wave, the delivery device (4) undergoing the diagnosis
Even if the receiver (5) is out of order, the output of the other receiver (5) is prohibited from appearing in the output of the adder (9). (2
0) is the received signal by the delivery of the ultrasonic waves of the delivery devices (4) and (5), and the diagnostic pulse application means (15) and (16).
) is an identification means for identifying the diagnostic pulse response signal from the diagnostic pulse response signal, and is constituted by a switch section (20a) and a control section (20b). This means that the output (S9) of the adder (9) is
As shown in (S9) of (3), the received signal (89a) and the diagnostic pulse response signal (S9b).

(S9c), and this output (S9) is directly transmitted to the receiving amplifier section (10), the delivery integrating section (11),
When passing through the reception comparison section (12), even if no harmful substance is present, the diagnostic pulse response signal (S9b), (S9
e) In order to prevent the distance measuring section (13) from mistakenly determining that an obstacle (6) exists, the output of the reference time generating section (1) is the time at which the ultrasonic wave is emitted. The distance signal generation timer (13a) is set to a logic value within the time period from the rising time of SL) to the time (to +T4) when the first diagnostic pulse (815) is applied to the receiver (4). 1"
During the period of time 73 or more during which the output is being output (for simplicity, this is referred to as time T3), the contact of the switch section (20a) is as shown in A.
It is controlled by a control unit (zob) so that the switch is switched to the side shown in the drawing, and the switch is switched to the B side shown in the figure at other times.

Therefore, the output (S9) of the adder (9) is divided temporally by this identification means (2), and the received signal (S9) in FIG. Only diagnostic pulse response signals (89b) and (89&) are on the contact B side.
Only S9c) appears. (21) is a diagnostic amplification means for amplifying the diagnostic pulse response signals (89b) and (89e) separated by the identification means (20) from the output (S9) of the adder (9); Comparison section [(2
1) Diagnostic integration means for integrating the output (23'm, output of this integration diagnostic means (22) ←Refer to 4th floor (c))
is a diagnostic comparison means for comparing with a predetermined reference value vr,
This output (822) disappears as shown in Figure 4 (Xun's (823).
823), which determines the failure state of the receiver (41, 51), for example, by counting the number of pulses output by the diagnostic comparator (23) every cycle T1. , determine the failure.That is, the receiver < 4
1 m If any one of (5) fails, 1
Since the number of pulses of the diagnostic comparator (23) that occurs in the period TI is not in accordance with the two pulses, the lamp (25a) of the failure display unit (25) is turned on at this time, and turned off at other times. Just set the output (S24) so that

Note that the count of this failure determining means (24) is cleared to zero by inputting the output (Sl) of the reference time generating section +11. The fault display section (25) has the same structure as the cane obstacle display section (14), but indicates a fault by lighting a lamp (25a) using a transistor (25b).

The first embodiment of the present invention is configured as described above, and
The operation will be explained in detail below.

About the operation of detecting the obstacle (6) by receiving the reflected wave of the ultrasonic wave emitted from the transmitter (2) by the obstacle (6) by the receivers (4) and (51) This is similar to the conventional ultrasonic obstacle detection device shown in FIG.

That is, when performing an operation to detect an obstacle (6), the switch section (19a) of the receiver output selection means (19)
.

(19b) is closed and the switch portion (20a) of the separating means (20) is set to the contact A side, so that the same operation as in FIG. 1 is performed.

When the output (sx3g) of the distance signal generation timer (13a) is at logic rOJ, the receiver (4) (5) Failure detection is performed. First, after a predetermined time T4 (Ts<Ta<Tl) has elapsed since the output (Sl) of the reference time generator (1) rises, the diagnostic pulse applying means (15) is applied to the receiver (4). applies a diagnostic pulse. At the same time as this diagnostic pulse is applied, the resonance characteristic switching means (17) operates for a time T6, and the resonance characteristic switching means (17) operates for a time T6.
7) q? The gender can be switched. If the receiver (4) is normal, it will freely oscillate at the resonant frequency due to this diagnostic pulse. The waveform at this time is (S19aa
) is a waveform with damped oscillation as shown in the figure below. Also, at this time, during time T6, the switch section (xc+b) n Il'
Only the output of the company waver (4) is input to the adder (9).

The response signal of the transfer device (4) that has passed through the adder (9) flows to the contact B side by the identification means (20), and is passed through the diagnostic amplification means (21).
).

By passing through the diagnostic integration means (22),
The signal waveform becomes as shown in (822). Tono's brim 52
2) is compared with a predetermined reference value vr of the diagnostic comparing means (23), and a pulse like (823) in FIG. 4 (11) is output.

If the receiver (41) is broken or deteriorated, resonance vibration will not occur even if a diagnostic pulse is applied, so the output (822) of the diagnostic integrating means (22) will be The predetermined reference value Vrl of the means (23) is not reached, and the output (823) of the diagnostic comparison means (22) remains at logic "0".When the diagnosis of the receiver (4) is completed, the Diagnosis of the receiver (5) is performed.As mentioned above,
The receiver output selection means (19) closes the switch section (19b) when diagnosing the receiver (4), and closes the switch section (19b) again after this diagnosis is completed. -z+)
At a predetermined time (to +T@) after a time (Ta + Ts) after the output (si) of the reference time generator ti) rises, the diagnostic pulse application means (16) applies a diagnostic pulse to the receiver (5). Apply. At the same time, the resonance characteristic switching means (1B) operates during time T6, and the characteristics of the resonance section (8) are switched. If normal, the delivery device (5) freely vibrates at a resonant frequency due to this diagnostic pulse.

The waveform at this time becomes a damped vibration waveform as shown at (819bb) in Figure 4 <b). During the time TII, the switch section (19a) is closed, and the adder section (9) is connected to the receiver (
Only the output of 5) is input. The response signal from the transfer device (5) that has passed through the adder (9), as in the case of diagnosing the receiver (4) described above, is the function-specific means (20) and the diagnostic amplification means (21).
, diagnosis 1; through the y1 integration means (22), the
The signal waveform shown in 2) and the diagnostic ratio 9 means (2)
3) Then, the pulse shown in the same figure (S23) is output. Regarding the operation related to the failure of the receiver (5), etc., the above-mentioned receiver (4)
).

In this way, the receivers (4) and (5) can operate normally.
The diagnostic comparison means (
23) outputs 20 pulse signals as shown in the 4th oral history). The fault determination means (24) counts this pulse signal, and when the count value during one period T1 is 2, the output is held at logic "0", and at least the receiver (4).

When one of (5) fails and the number of pulses output by the diagnostic comparison means (23) becomes 1 or less, the output (824
) is set to logic "1". According to the parable,
1] The transistor (25b) of the fault display section (25) turns on and the lamp (25a) lights up, causing the transfer device (5
) can display malfunctions, etc.

Note that the resonance characteristic switching means (17) t (r8) is the resonance section (7).

The time T6 during which the resonance characteristics are switched by acting on (8) is (317) and (818) in Fig. 4 (e) and (i).
) is limited to those shown. That is, the resonant part (7)
, (81 should not operate during fault diagnosis, so the time (t.

Even if the receiver (
41, the output of (5) will be the same.

FIG. 5 is a schematic diagram showing a second embodiment of the present invention. It's a V composition. Here, the diagnostic pulse applying means (15) consists of registers (15a), (15b) and a pulse generating section (26), and the pulse generating section (26) consists of (81) in FIG. 4(e).
At the same timing as 7), a pulse that hits logic "1" is output at the time of switching. This pulse is (815
) as shown in Fig. 4(c), since the fc and fx impulse-like ones are difficult to obtain, so if this is applied to the receiver (4) via the registers (15a) and (15b), the result shown in Fig. 4(c) is obtained isometrically. This has the same effect as applying the impulse-like pulse shown in (815). In addition, resonance characteristic switching means (17)
is analog switch (17a) e-inverter (17
b) and the pulse generator (26), and the obstruction (6).
), the analog switch (17a) is turned on and the resonant section (7) has the same configuration as the resonant section (7) shown in FIG. 6a) can be performed. When the output of the pulse generator (26) is logic "1", the analog switch (17a)
is turned off, and the capacitor (7b) of the resonant section (7) is electrically turned off, so that resonance 0 is switched. Furthermore, the pulse generator (26), together with the transistor (19aa) and the register (19ab), constitutes a receiver output selection means (19) 174, and by turning on the transistor (19ba), the receiver (5 ) is prohibited from being input to the adder (9). The diagnostic pulse application means (16) for diagnosing the receiver (5), and the resonance characteristic switching means (8) are the diagnostic pulse application means (15) for diagnosing the aforementioned receiver (4).
, has the same configuration as the resonance characteristic switching means (17), and the output of the pulse generator (27) is set to logic "1" at the time (t) as in FIG. 4 (818). o −1
-Ts). In addition, pulse generation t'fl
The output of s (27) turns on the transistor (19aa) of the receiver output selection means (19), and prohibits the output of the receiver (4) from being input to the m0 section (9). In this actual Mli example, the output (S9) of the adder (9) is similar to (S9) in FIG. 4(g). The output (S9) of the adder (9) is sent to the identification means (2o
) without passing through the reception amplification section (10), and further, similar to the signal transmission path of the reception signal, the reception integration section (11),
The signal passes through the received wave comparison section (12). This is the receiver (4
This is an effective method when the received signal from the reflected wave (6a) in 1.(5) and the diagnostic pulse response signal from the diagnostic pulse application means (15) and (16) are approximately the same in magnitude. Needless to say, circuit construction becomes easier. Therefore, the output (
811), the output (312) of the receiving comparison unit (12) is (311) in Fig. 6(d) and (e), respectively.
The result will be as shown in (812). This comparison section for receiving waves (
The output (312) of 12) is identified by the identification means (28) and distributed to the ranging section (13) and the failure determination means (24). This identification means (part) is an AND gate (28
a), (28b), is set to 0 by the inverter (28c) as shown, and the distance signal generation timer (13a
When the output (313a) of ) is logic [moon, the output (S12) of the received wave comparing unit (12) is input only to the distance measuring unit (13), and similarly, when the logic is "0", the output (S12) of the receiving comparator (12) is inputted only to the distance measuring unit (13).
24) only. The failure determination means (24) includes a binary counter (24a), a Nantes gate (24b), and an inverter (24c).

From (24d), F, F, (24e), the binary counter (24a) sets the outputs A and B by counting the number of pulses input to the terminal CK, and sets the outputs A and B to the terminal R. The count is cleared to zero at the rising edge of the input pulse.

If the count value is 2, the output A becomes the logic rOJ, the output 8 logic "1", and the output of the NAND game (24b) becomes the logic "0". Output 6 of this Nantes gate (24b)
is input to the data terminals p, F, (24e), latched at the rising edge of the clock terminal CK, and output Qf! Since c is set, lamps (24a) r, l: do not light up.

If the total f1 value is 1 or less, the output Qti of F, F, (24e) is set to "1" and the lamp (25a) lights up to indicate a failure of the receiver.

FIG. 7 is a schematic diagram t1') showing the bottom opening of a third embodiment of the present invention. In this collective example, in the embodiment of Fig. 3 or Fig. 5, the logical operation r? regarding time control is used. This function is performed by a microcomputer (29) (hF)
, has the same effect as the above-mentioned embodiment, and can further reduce the number of parts constituting the circuit.

By the way, in the above embodiment, the resonance part (7) 2 (8
) and resonance characteristic switching means (17), (18),
As shown in Fig. 8, a transistor (17c) and a resistor (17d) are used in place of the analog switch (17a).
, (17e) to form M\ has the same function.

Further, the configuration after the adding section (9) may be configured as 4'' as shown in FIG. 9 depending on the magnitude of the received wave signal and the diagnostic pulse response signal.

Furthermore, the failure of the receivers (4) and (5) is caused by the failure of the lamp (2).
5a) is displayed by lighting it up, but the display is not limited to indicating a failure; by detecting a failure, it may be possible to switch to a spare receiver prepared in case of a failure.

[Effect of emit ■]]

As explained above, according to the present invention, the ultrasonic obstacle detection device includes 9, a diagnostic pulse application means, a resonance characteristic switching means, a receiver output selection means, a diagnostic amplification means, a diagnostic detection means, and a fault detection means. Since the failure detection circuit is provided with a determination means and an identification means, failures in the receiver can be reliably detected, which has the effect of improving the reliability of the device.

[Brief explanation of the drawing]

Figure 1 does not show a conventional ultrasonic obstacle detection device, but the outline is 41.
・Bottom opening, Figures 2 (a) to (f) explain its operation [JI
FIG. 3 is a schematic configuration diagram showing the first embodiment of the present invention, FIG. 4(a) to (0) are timing charts explaining its operation, and FIG.
! Schematic configuration diagram showing the second embodiment of Jj, FIG. 6(a) ~
(f) is a timing chart explaining the operation;
The figure does not show the third embodiment of the present invention, but is a schematic eleventh diagram, tl
) Figures 8 and 9 are partial explanatory diagrams showing other embodiments of the present invention. (11... Reference time generation section, (21@... Transmitter, (3)... Transmitter drive section, (41, (51...-
11 received waves? ni1(7), (81・Fist・Resonance part, (
9)...Addition section, (10)... Wave receiving amplification section,
(11) --- For wave reception 1. )'r part, (12)...
... Comparison section for received wave, (13) ... i'llll distance section,
(14)...Obstacle display section, (15), (1e
)...Diagnostic pulse application means, (17), (18
)...Resonance characteristic switching means, (19)...Receiver output selection means, (20), (28)...Identification means, (21)...Diagnostic amplification means , (22)...
・Diagnostic integration means, (23)...Diagnostic comparison means,
(24)...Failure determination means, (25)...Fault display section, (26), (27)...1llll pulse generation section,'(29)...Microcomputer. Agent Masuo Oiwa Figure 4 procedural amendment (voluntary) 1932? 2003-] and Mr. JPO Commissioner 1, Indication of the case, Patent Application No. 171578-1983, Department to Katayuni, the representative of the person making the amendment (11 Akinori Tatami, page 12, No. 9 Bamboo and No. 14 (21 Ibid., p. 16, line 12, "closing" is amended to "kaisei". (3) Ibid., p. 17, line 8 and "Close" in line 19 is amended to "open" respectively. (4) "Because it is not a thing" in line 13 of page 19 of the same book is amended to "it is not a thing".

Claims (1)

[Claims] (1) A reference time generator that generates a pulse signal having a predetermined period and indicating the reference time, and receiving the output of the reference time generator, drives at least one ultrasonic transmitter to emit ultrasonic waves. a transmitter small vibration part, a plurality of ultrasonic receivers each consisting of a vibrator having the same resonance frequency as the frequency of the ultrasonic wave, and each ultrasonic wave receiver that expands the resonance width of the ultrasonic receiver. a resonating section, an adding section for adding the outputs of each of the ultrasonic receivers, a receiving amplifier section for amplifying the output of the adding section, and a receiving amplifier section for integrating the output of the receiving amplifier section. an integrating section, a receiving comparison section that compares the output of the delivery integration section with a predetermined reference value, and a distance from the output of the transfer comparison section and the output of the reference time generation section to the obstacle. a diagnostic pulse applying means for sequentially applying an impulse signal to each of the ultrasonic receivers based on the output of the reference time generating section; resonance characteristic switching means for switching the characteristics of the resonant section for a predetermined period of time after application of a pulse signal by the diagnostic pulse application means; adding the response signal generated in any one of the ultrasonic wave receivers by the wave receiver output selecting means and the diagnostic pulse applying means so that only the output is input to the adding section; a diagnostic amplifying means for amplifying the output of the diagnostic amplifying means; a diagnostic integrating means for integrating the output of the diagnostic amplifying means; a diagnostic comparing means for comparing the output of the diagnostic integrating means with a predetermined reference value; failure determination means for determining the failure state of the several 7π ultrasonic receivers based on the output of the diagnostic comparison means; and an identification means for distinguishing the response signal generated in the ultrasonic receiver. A failure detection circuit for an ultrasonic obstacle detection device. (The scope of claims in which the wave reception amplification section also serves as the diagnostic tc17 amplification means, the wave reception integration section also serves as the diagnosis comparison means, or the wave reception comparison section also serves as the diagnosis comparison means for the powder food fJ) 2. A failure detection circuit for the ultrasonic obstacle detection device according to item 1.