JPS62274284A - Obstacle detector for vehicle - Google Patents

Abstract

PURPOSE:To preclude malfunction by judging the couple of ultrasonic wave transmitter receivers whose horn axes are slanted to the center sides are abnormal and generating a warning when direct wave signals which are transmitted by the transmitters receivers and then received by themselves are lower than a specific level. CONSTITUTION:A switching control circuit 2 switches contacts of interlocking relays X, Y, and Z in order synchronously with an ultrasonic pulse signal (a) from an oscillation circuit 1. Signals b1 and b2 passed through the relay X are transmitted by a transmitter receiver S1 and received S2, transmitted S2 and received by S2, and transmitted S1 and received by S2, thus repeating respective modes of wave reception. Received signals are passed through a receiving circuit 6 and an AND circuit 7 to discriminate a reflected wave within a constant distance range, thereby putting an annunciator I in operation. Further, specific pulse widths are set in monostable multivibrators 10, 11, and 12 and in a normal state, a pulse is outputted from an AND circuit 14 at every time to reset an integrating circuit 15. If the wiring of the transmitter receiver S1 of S2 is broken, the received signals decrease in width, so the output of an AND circuit 14 is ceased and the output voltage of the circuit 15 rises to put an alarm 17 in operation, thus precluding malfunction.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Industrial Application Field) The present invention provides a method for installing a pair of FFI sound wave transducers in parallel on the bumper of a vehicle, so as to avoid obstacles at the rear of the vehicle. This invention relates to disconnection detection of a transducer in a vehicle obstacle detection device that detects the presence of an object.

(Prior Art) When backing up a car into a garage, etc., if the parking space is narrow, it is difficult to do so smoothly and quickly without hitting obstacles.

Therefore, various detection devices have been proposed that use ultrasonic transducers to detect obstacles behind the vehicle. As shown in Figure (a), the detection area A by the sensor "aS" installed at the rear of the vehicle C is considerably larger than the vehicle width W of the vehicle C, and if the entrance to a garage etc. is narrow, the entrance pillar etc. There was a problem in that the sensor S was detected as an obstacle O, causing a malfunction even though there was no obstacle in the parking space.Also, as shown in Figure 8(b), the sensor S was placed in the center of the vehicle C. Although it is possible to install it close to the front, there is a problem that a blind spot 2 will be created at a short distance.

In order to solve this problem, the applicant has proposed the method shown in FIG. 8(a).
Both outer transducers are installed facing inward, and in order to reduce costs, the central transducer is omitted from among the transducers shown in Figure 8(a) to expose the central detection area. The transducer S1゜S2 first transmits and receives waves with the transducer S1, then after a certain period delay transmits and receives waves with the transducer S2, and again with a delay of 11 cycles, transmits and receives the waves with the transducer S1. We have previously proposed a device that detects obstacles by receiving waves with the transducer S2 and then returning to the original state.

By the way, as shown in Japanese Patent Laid-Open No. 57-42866, for example, such an obstacle detection device is equipped with a function to check and notify when the ultrasonic transducer 1li11 or the like fails. Are known. That is, the device disclosed in this publication uses a transmitter and a receiver as separate units, and is designed to perform a logical product of the transmitted wave and the received wave to check for failures. However, the above-mentioned configuration proposed by the present applicant in which the transducer and receiver, which transmit and receive waves in one unit, is operated in a scanning manner using two hooks, is different from the structure in which the transmitter and receiver as shown in the above publication are used. 1l when the wave device is separate
The following problem arises when using the ia check technique.

(1) Unless the transmitter and receiver circuits are reliably separated in terms of ultrasonic action, if the wire is disconnected, the transmitted wave component will electrically enter the receiving side and the wave will be received during the transmitting time. It may malfunction as if the component were present.

(2) When using the scanning method, the magnitude of the direct wave component from the transmitter to the receiver is much larger and the same when transmitting and receiving is carried out in one body and when it is carried out separately. It becomes difficult to judge the presence or absence of direct waves based on the level.

In other words, if we judge based on a low level, when the transmitter and receiver are detected together, even if there is a disconnection, the electrical component mentioned in (1) above will be large, making it impossible to detect the disconnection, and if we judge based on the high level, the transmitter and receiver will Since the received signal when detecting a separate object is small, false detection is likely to occur.

(Object of the Invention) The present invention has no blind spots in the detection area of the ultrasonic transducer, and furthermore, the area has a diagonal shape that is slightly wider than the vehicle, thereby making it easier to back up the vehicle, park the vehicle, etc. It is an object of the present invention to provide a small dual-use obstacle detection device that can perform smooth and quick check for disconnection of a transducer.

(Structure of the Invention) The present invention provides an ultrasonic transmitter/receiver that is installed in parallel on both sides of the vehicle, detects the presence of an obstacle on the way back to the vehicle, and issues a warning and display. In the object detection device, a pair of ultrasonic transducers are arranged side by side with their horn axes tilted toward the center of the vehicle, and a first mode in which the transducer transmits waves and receives reflected waves by itself; and a second mode in which a wave is transmitted by one transducer and the reflected wave is received by the other transducer, and when in the second mode, the reflected wave signal and is provided with a received signal forming means for forming another received signal, detects the presence or absence of the direct wave signal in the first mode, and determines that the transducer is abnormal when the direct wave signal is below a predetermined level. This means that there is a means to do so.

(Example) In FIGS. 1 and 2(a) and (b), a pair of ultrasonic transducers 81.32 are arranged in parallel at the rear of the vehicle C, and the transducers 3S1.32 are located at both ends thereof. Center axis A of S2 horn
1. Angle θ of A2 toward the center of the vehicle.

It is only tilted. The mounting height may be within a range where the vertical detection area A does not falsely detect the road surface. Generally, the detection area of an ultrasonic transducer (ultrasonic sensor) is narrower near the horn opening and increases as the distance from the horn increases. The detection area here refers to the maximum area that the ultrasonic transducer detects and displays when an obstacle of a specified size is placed perpendicular to the central axis of the horn. Refers to the range.

When installed in this manner, the area in the vehicle width direction of the detection area A becomes a rectangular area slightly wider than the vehicle width, as shown in No. 2121(a). In the figure, O indicates an obstacle such as a garage entrance, B indicates a bumper on the trunk of the vehicle to which the transducer 81.
warns of the presence of obstacles such as a buzzer or lamp,
The displayed alarm, CN, is a connector that connects the transducer 81, 82 and the electronic control circuit unit ECU.

Next, the configuration of the first embodiment of the electronic 1llI1 circuit unit ECU will be explained with reference to FIG. 3, and the time chart of its operation will be explained with reference to FIG. 4. The fRF control circuit unit ECU includes an oscillation circuit 1 and relays X and Y.
, a switching & IJ 1 circuit 2 that performs switching control of Z, and a gate circuit 3 that performs a determination function as described later.
The output of the drive control circuit 4 that controls these and the oscillation circuit 1 is input via the relay :,
A that calculates the AND of the gate circuit 3 and the wave receiving circuit 6, where the reflected and received wave due to the transmitted and received wave fSS1.82 is input via the relay Y and is amplified, waveform shaped, and detected.
An ND circuit 7, a memory circuit 8 that stores the output of the AND circuit 7, an alarm drive 1 path 9 that drives the alarm I based on the output of the memory circuit 8, and a unit driven by the drive control circuit 4. A stable multivibrator 10, a monostable multivibrator 11 driven by this monostable multivibrator 10, a monostable multivibrator 12 driven by the drive 611m circuit 4 via the contact z3 of the relay 2, and a wave receiving circuit. OR circuit 13 which takes the logical sum of the output of 6 and monostable multivibrator 12, and logic 1 of monostable multivibrator 11 and OR circuit 13! I! An AND circuit 14 that takes the product, an integration circuit 15 that receives the output of this AND circuit 14 as input, an alarm drive n-path 16 that is driven by the output of this integration circuit 15, and is driven by the output of this 1-report drive circuit 16. Alarm device 1 to notify of abnormality
It is composed of 7 etc.

Also, relay contact X1 of relay X- on the transmitting side. X3 is connected to the line of one transducer S1 side, relay contact x2 is connected to the line of the other transducer S2 side, and relay contact Y1 of relay Y on the receiving side is connected to the line of one transducer @S1 side. Relay contacts Y2 and Y3 are connected to the line on the other transducer S2 side, and relay contacts 11 .
22 is not connected anywhere, and only the relay contact Z3 is connected to the drive circuit 4 and the monostable multivibrator 15.

Mata, said switching @@DllII2, ;b'JI/
-X, Y.

2, the first mode receives the reflected wave with the transmitter/receiver itself, and the first mode transmits the wave with one transmitter/receiver and receives the reflected wave with the other transmitter/receiver. The second need for receiving waves is obtained. Furthermore, the monostable multivibrator 12, the OR circuit 13, etc. constitute a received signal forming means that forms a received signal different from the reflected wave signal in accordance with one of the transmitted waves in the second mode, and the AN D lvl road 14. By the integrating circuit 15 etc.,
A means for determining an abnormality such as a disconnection failure in the transmitting/receiving wave is configured.

- [The operation of the above structure will be explained below with reference to FIG. (1) First, the signal a is output from the oscillation VA path 1.

(2) In synchronization with this signal a, a signal for switching the contacts of relays X, Y, and Z is output from switching control circuit 1 2.

(3) Upon receiving the signal in (2) above, the relay contacts of relay X turn on as X14X24X34X1..., 0FFL/,
Similarly, the relay contacts of relay Y are Y1 → Y2 → Y3 → Y1
...and repeats turning ON and OFF sequentially.

('4) When the relay contact of relay X is closed, the signal from oscillation circuit 1 is transmitted as bl and b2 to the transmitter section! e circuit 5-1.5-2.

(5) The signal in (4) above is transmitted to the transmitter drive circuit 5-1゜5-
2, the signal is amplified and converted into a drive signal, and then sent to the transducer 81.
The ultrasonic transducer 82 is driven to transmit an ultrasonic signal.

(6) On the other hand, relay contact Y1 on the receiving circuit 6 side. Y2, Y
3 is also operating with Xl, X2, X3 and ffAU time >)j, so the transducer S1. At S2, the emitted ultrasonic signal is directly input as a receiving input signal to the receiving circuit 6, where it is amplified, waveform shaped, and detected, and an output signal C is output.

(7) The gate circuit 3 deletes the input signal in (6) above that is not a reflected wave, and emits an output d for determining whether the reflected wave is within a certain distance. If the wave is within a certain distance, the AND circuit 7 outputs an output signal e, which is held in the memory circuit 8 as a signal f and drives the alarm (2) via the alarm drive circuit 9.

Furthermore, to explain the details of the signal reception, (1) After turning on the power switch (not shown), first contact X1 of relay
Signal ■ is output from , and at this time contact Y of relay Y
1 is ONL, the transmitted signal (2) goes around to the transducer S1 as it is, and the received signal (2) is obtained (first mode). At this time, in the present invention, since the transducer S1.82 is inclined, if we assume that the obstacle 0 is located near the bumper at the center of both as shown in FIG. The wave reflected by the obstacle due to the wave transmitted from the transmitter/receiver S1 does not return to the transducer S1, and is not received by the transducer S1. Further, since contacts Y2 and Y3 of relay Y are at 0FFL, the wave reflected by the obstacle is not received by the transducer S2.

(2) Next, contact x2 of relay The transmitted signal (2) goes around to the transducer S2 as it is, and the received signal (2) is obtained (first t-mode). At this time as well, the obstacle reflected wave is not received by the transducers S1 and S2, as described above.

(3) Next, contact x3 of relay , the transmitted wave signal ■ electrically wraps around to the transducer S2, and the received wave signal ■
is obtained (second mode). At this time, as shown in FIG. 3, the wave reflected by the obstacle due to the wave transmitted from the transducer S1 travels toward the transducer S2, and is received as a signal ■' by the transducer WSz.

(4) Create a rectangular wave d corresponding to the distance jo (Fig. 2) to be detected by the gate circuit 3, and combine this with the output C of the wave receiving circuit 6.
By taking an AND with the AND circuit 7, the output e within the detection range is taken out, the memory circuit 8 is operated, the drive output of the alarm 3 is obtained via the alarm drive circuit 9, and a buzzer etc. is used to detect the obstacle. Make your presence known.

Next, the function of checking whether the IN function is operating properly will be explained. FIG. 4 shows the case when it is operating normally. In order to check whether there is any disconnection with the transducer, the transducer detects the wave directly as an electrical signal (as an ultrasonic wave).

A long pulse T1 is obtained at the receiver circuit output C corresponding to the received signals (2) and (2) in the first mode in which only direct waves are extracted. On the other hand, in the second mode, since there is only electrical loopback, only a short pulse T2 L/ can be obtained from the receiving circuit output C corresponding to the received signal (2) at this time.

Therefore, the output Q of the monostable multivibrator 10 is T2≦
Select T4 <TI, monostable multivibrator 11
The output value is chosen to be TI +75χT1.

Then, the monostable multivibrator 11 counts T5 from the time when the output of the monostable multivibrator 10 falls. The monostable multivibrator 15 is operated only in the second mode in which transmission and reception are performed by separate transducers,
The output 1 is made to be 3~T1.

If each pulse width T is set as described above, a pulse approximately equal to Ta and Ts will be outputted to the output i of the AND circuit 14 every time. When this output i is present, the next output j of the integrating circuit 15 is reset each time, so it never exceeds a predetermined level V, and the alarm drive circuit 16 does not output an output until this level V is exceeded. Therefore, the alarm 17 does not work during normal operation.

Next, the case where the wiring to the transducer S1 is an i-line will be explained with reference to the timing chart of FIG. Here, only the pulses of the receiving wave and alarm section are shown.

The right side of the arrow in Fig. 5 is in a disconnection state, and when the disconnection occurs, the width of the received signal ■ of the transducer S1 becomes small, and the output pulse width of the wave receiving circuit 6 also becomes small as ■1 → T1-. Become.

Therefore, if the wire breaks and the pulse width becomes T1', the AND circuit 14
Output 1 disappears, and the output of the integrating circuit 15 is not reset and exceeds level V, which determines that the transducer is abnormal, and the output of the H alarm drive circuit 16 is output to activate the alarm 17. .

FIG. 6 shows the configuration of a second embodiment of the electronic control circuit unit ECLJ. Stable multivibrator 12, OR circuit 13
In place of the relay Z, one transducer 81 and the other transducer S2 are connected via a capacitor C.

That is, the transmission signal valve to the transducer S1 is connected to the capacitor C.
In the second mode, in the first embodiment, the stray capacitance is connected to the receiving circuit of the transducer S2 via the transducer S2.
This is an enlarged version of the one in which there was only electrical loopback from 1 to the transducer $2. The main part of the time chart for this embodiment is shown in FIG. In the figure, the pulse width Tw of the output C of the wave receiving circuit 6 corresponding to the received wave signal ■ in the second mode is set to be as long as that of the other signals (T1).

With this configuration, when the transducer S1 is disconnected, the pulse width T1 of the output C of the wave receiving circuit 6 corresponding to the received signal ■ becomes shorter, and when the transducer S2 is disconnected, the pulse width T1 of the output C corresponding to the received signal ■ becomes shorter. The pulse width T1 of the output C of the wave circuit 6 is shortened, and in the same manner as described above, both are determined to be abnormal and an alarm can be issued.

In short, in the present invention, in each embodiment, the transducer S1
, S2, when the transducer is integrated (first mode), the level (time width) of the original direct wave, that is, the reflected wave signal, is compared with the reference value to check for disconnection. When making a judgment that the transducer is separate (second mode), use the monostable multivibrator 12 or the like, or create a dummy signal using the capacitor C to generate a dummy signal instead of a direct wave. This compensates for short signals with only electrical loopback, prevents erroneous judgments, and enables accurate ItJi11 checks.

(Effects of the Invention) As described above, according to the present invention, there are two modes: the first mode in which the transducer transmits the wave and receives the reflected wave by itself; a second mode of receiving the wave with a wave transmitter, and forming a received signal different from the reflected wave signal in response to the one transmission in the second mode; By providing means for detecting the presence or absence of a direct wave signal in the first mode and determining that the transducer is abnormal when the direct wave signal is below a predetermined level, the transducer can be separated. By creating a dummy signal by the received wave signal forming means, there will be no malfunction of the disconnection check even though the level of the reflected wave is small, and the transducer can be integrated into a single unit. Sometimes, accurate wire breakage checks can be made by checking for wire breaks using high-level reflected waves that are original direct waves.

[Brief explanation of the drawing]

FIG. 1 is a conceptual configuration diagram of the vehicle obstacle detection @ installation of the present invention,
Figures 12(a) and 12(t)) are explanatory diagrams of the IQ book detection function by the same device, and Figure 3 is a diagram showing the IQ book detection function of the device according to the first embodiment.
Fig. 4 is a time chart showing the operation of the structure of the first embodiment in normal conditions, Fig. 5 is a time chart showing the operation in abnormal conditions, and No. 6rA is the second embodiment of the device of the present invention. FIG. 7 is a time chart showing the operation of the configuration of the second embodiment, and FIGS. 8(a) and 8(b) are schematic configuration diagrams of a conventional vehicle obstacle detection device. SL, S2... wave transmitting/receiving product, X, Y, Z,... relay, C... capacitor, 1... oscillation circuit, 2... switching control circuit, 6... wave receiving circuit, 10.11.12...
・Monostable multivibrator, 13...OR circuit, 1
4...AND circuit, 15...Integrator circuit, 16...
Alarm drive circuit, 17...alarm device. Patent applicant Matsu) Electric Works Co., Ltd. Agent
Patent Attorney Etsushi Kotani Patent Attorney Cho 1) Masamukai Patent Attorney Yasuo Itaya Figure 7

Claims (3)

[Claims] 1. In a vehicle obstacle detection device, a pair of ultrasonic transmitters and receivers are installed in parallel on both sides of the rear of the vehicle to detect and issue a warning when there is an obstacle behind the vehicle. The first method is to install transducers in parallel with their horn axes tilted toward the center of the vehicle, and to receive the reflected waves by the transducer itself that transmitted the waves.
mode, and a second mode in which one transducer transmits a wave and the reflected wave is received by the other transducer,
A received wave signal forming means is provided for forming a received wave signal different from the reflected wave signal in response to the one transmission wave in the first mode, and detects the presence or absence of the direct wave signal in the first mode. 1. An obstacle detection device for a vehicle, comprising means for determining that a transducer is abnormal when a direct wave signal is below a predetermined level. 2. A patent characterized in that the received signal forming means is composed of a monostable multivibrator that generates a pulse signal when in the second mode, and an OR circuit of the monostable multivibrator and the received signal generated by the reflected wave. An obstacle detection device for a vehicle according to claim 1. 3. 2. The vehicle obstacle detection device according to claim 1, wherein the received signal forming means is constructed by connecting one transducer and the other transducer via a capacitor.