JPH063437A - Obstacle detector - Google Patents

Abstract

PURPOSE:To enable accurate detection of temporary abnormality as caused by freezing, fouling or the like of an ultrasonic vibrator and permanent abnormality such as disconnection and short-circuiting requiring repairs separately in an obstacle detector which detects obstacles by transmitting or receiving an ultrasonic wave using the ultrasonic vibrator. CONSTITUTION:It is judged whether a detection signal SB moves to a high level or not from reverberation of an ultrasonic vibrator within a judging period T after the stoppage of the driving of the ultrasonic vibrator. When the detection signal SB is at a low level within the judging period T2, permanent abnormality of the ultrasonic vibrator is detected. When no permanent abnormality is generated, it is judged whether the detection signal SB moves to the high level or not within the judging period T3 after the elapse of the judging period T2 to determine whether the reverberation of the ultrasonic vibrator lasts for a specified time as in the normal time. When the reverberation does not last as in the normal time, temporary abnormality is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic obstacle detecting device for transmitting an ultrasonic wave to the outside and detecting an obstacle from the reflected wave.

[0002]

2. Description of the Related Art Conventionally, in this type of obstacle detection device, an ultrasonic transducer is driven for a predetermined time to transmit the ultrasonic wave to the outside, and then the transmitted ultrasonic wave is transmitted to the outside. The presence or absence of an obstacle and the distance to the obstacle are detected by detecting the reflected wave reflected by the obstacle.

Further, in this type of device, if the ultrasonic transducer does not operate normally, it becomes impossible to accurately detect an external obstacle. Therefore, the ultrasonic vibration is immediately after the driving of the ultrasonic transducer is stopped. Based on the reverberation signal output from the child, it is judged whether the operating state of the ultrasonic transducer is operating normally, and if the ultrasonic transducer is not operating normally, that fact is displayed. Has been

That is, when the ultrasonic transducer is operating normally, even if the driving of the ultrasonic transducer is stopped, the ultrasonic transducer continues to vibrate due to reverberation for a while, and the ultrasonic transducer continues to vibrate. Since a signal indicating the reverberation state (reverberation signal) is output from the device, conventionally, by determining whether or not the reverberation signal is present after the ultrasonic transducer drive is stopped, the abnormality of the ultrasonic transducer is detected. Is to be detected.

[0005]

However, in the conventional obstacle detection device, the abnormality of the ultrasonic transducer is determined by determining whether or not the reverberation signal is present after the driving of the ultrasonic transducer is stopped. Therefore, when the ultrasonic transducer is not completely operating due to disconnection or short circuit, the abnormality can be accurately detected, but the ultrasonic transducer itself freezes or the ultrasonic transducer is damaged. It was not possible to accurately detect a temporary abnormality of the ultrasonic vibrator in which the vibration of the ultrasonic vibrator is suppressed by the adhesion of mud or wax.

For this reason, in the conventional obstacle detection device, the user can normally operate if the abnormality is a permanent abnormality that needs repair due to disconnection, short circuit or the like, or if the condition such as freezing is eliminated. There was a problem that it was not possible to display whether it was a temporary error that could be recovered.

The present invention has been made in view of the above problems, and accurately identifies a temporary abnormality due to freezing or dirt of the ultrasonic transducer itself and a permanent abnormality such as disconnection or short circuit which requires repair. An object of the present invention is to provide an obstacle detection device that can detect an obstacle.

[0008]

SUMMARY OF THE INVENTION An obstacle detecting apparatus according to claim 1, which is made to achieve the above object, comprises an ultrasonic transducer capable of transmitting and receiving, as illustrated in FIG. The ultrasonic vibration is connected to a driving unit that outputs a driving signal to the ultrasonic vibrator for a predetermined time and transmits ultrasonic waves from the ultrasonic vibrator, and a signal path from the driving unit to the ultrasonic vibrator. An amplification circuit for amplifying the vibration signal of the child, a detection circuit for detecting the vibration signal amplified by the amplification circuit, and the ultrasonic wave from the detection circuit immediately after the driving means stops driving the ultrasonic vibrator. A first abnormality detecting means for determining whether or not a detection signal representing the reverberation after the drive of the vibrator is stopped is output, and detecting an abnormality of the ultrasonic vibrator when the detection signal is not output; , The ultrasonic transducer by the driving means After a lapse of a predetermined time after completion of driving, it is determined whether or not a detection signal indicating vibration due to a reflected wave from the obstacle of the ultrasonic transducer is output from the detection circuit, and the detection signal is output. In the obstacle detection device for a vehicle, which is provided with an obstacle detection means for detecting an obstacle, the external force generated due to freezing, dirt, etc. of the ultrasonic transducer itself is provided separately from the first abnormality detecting means. The present invention is characterized in that a second abnormality detecting means for detecting a temporary abnormality of the ultrasonic oscillator, in which vibration of the ultrasonic oscillator is suppressed, is provided.

The obstacle detection device according to the second aspect is
A second detecting circuit for detecting a temporary abnormality of the ultrasonic transducer, wherein the second abnormality detecting means detects a vibration signal smaller than an output signal of the amplifier circuit; And a temporary abnormality determining means for determining a temporary abnormality of the ultrasonic transducer based on a second detection signal representing the reverberation of the ultrasonic transducer output from the second detection circuit. I am trying.

Furthermore, an obstacle detecting apparatus according to a third aspect of the present invention is the obstacle detecting apparatus according to the first or second aspect, wherein the obstacle detecting apparatus includes a first abnormality detecting means and a second abnormality detecting means, respectively. It is characterized in that an abnormality display means is provided for distinguishably displaying the detected abnormality of the ultrasonic transducer.

[0011]

In the obstacle detecting device according to claim 1 configured as described above, first, the driving means outputs a driving signal to the ultrasonic transducer for a predetermined time so that the ultrasonic transducer transmits the ultrasonic wave. Then, the amplification circuit amplifies the vibration signal of the ultrasonic transducer including the drive signal, and the detection circuit detects the vibration signal amplified by the amplification circuit. Then, when the driving means stops driving the ultrasonic transducer, the first abnormality determining means determines whether or not the detection signal indicating the reverberation after the ultrasonic transducer is stopped is output from the detection circuit. By detecting the abnormality of the ultrasonic vibrator, when the driving of the ultrasonic vibrator by the driving means is finished and a predetermined time elapses,
The obstacle detecting means detects the obstacle by determining whether or not a detection signal indicating the vibration of the ultrasonic transducer caused by the reflected wave from the obstacle is output from the detection circuit.

In the obstacle detecting device, the second
The abnormality detecting means detects the temporary abnormality of the ultrasonic vibrator in which the vibration of the ultrasonic vibrator is suppressed by the external force generated by the freezing or dirt of the ultrasonic vibrator itself. That is, when the ultrasonic transducer does not operate at all due to disconnection, short circuit, or the like, there is almost no reverberation after the ultrasonic transducer is stopped driving, and the first abnormality determination means detects such ultrasonic waves. Although it is possible to accurately detect the permanent abnormality of the ultrasonic oscillator, when the ultrasonic oscillator is temporarily abnormal in which vibration of the ultrasonic oscillator is suppressed by external force caused by freezing or dirt of the ultrasonic oscillator itself, Since this cannot be accurately detected by the abnormality determining means of the present invention, in the present invention, a second abnormality detecting means for detecting a temporary abnormality of the ultrasonic sensor is provided separately from the first abnormality determining means. hand,
The temporary abnormality can be accurately detected.

It is to be noted that the vibration signal representing the vibration of the ultrasonic transducer is not directly input to the detection circuit, but is amplified by the amplification circuit and then input to the detection circuit by the reflected wave from the obstacle. This is because the generated vibration of the ultrasonic vibrator is significantly smaller than the vibration of the ultrasonic vibrator caused by the drive signal of the ultrasonic vibrator and the reverberation after the driving is stopped. That is, by amplifying the vibration signal from the ultrasonic transducer using the amplifier circuit, the detection circuit can accurately detect the vibration signal due to the reflected wave from the obstacle of the ultrasonic transducer.

Next, in the obstacle detecting device according to the second aspect, the second abnormality detecting means includes the second detection circuit and the temporary abnormality determining means, and the temporary abnormality determining means includes the second abnormality detecting means.
The temporary abnormality of the ultrasonic transducer is determined based on the second detection signal representing the reverberation of the ultrasonic transducer output from the detection circuit.

That is, first, since the amplifier circuit is for allowing the detection circuit to accurately detect the weak vibration of the ultrasonic vibrator due to the reflected wave from the obstacle, the ultrasonic vibrator vibrates greatly. When the ultrasonic transducer is driven or reverberates, the amplifier circuit saturates and the output of the amplifier circuit reaches the maximum level. Therefore, even at the end of reverberation when the vibration of the ultrasonic transducer is weakened, the detection circuit outputs the detection signal representing the reverberation of the ultrasonic transducer, and the ultrasonic transducer obtained based on this detection signal is output. The reverberation time of does not differ greatly between when the ultrasonic transducer is normal and when it is temporarily abnormal.

Therefore, in the obstacle detecting device, the vibration signal before amplification by the amplification circuit, which changes according to the vibration state of the ultrasonic transducer, is detected, and the detected vibration signal (second detection signal) is detected. By determining the temporary abnormality of the ultrasonic transducer, the temporary abnormality of the ultrasonic transducer can be easily detected.

On the other hand, the obstacle detecting device according to a third aspect of the present invention is the obstacle detecting device according to the first or second aspect, wherein the abnormality display means includes the first abnormality detecting means and the second abnormality detecting means. The abnormality of the ultrasonic transducer detected by the means, that is, the permanent abnormality and the temporary abnormality of the ultrasonic transducer are displayed in a distinguishable manner.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 2 is a block diagram showing the overall configuration of a vehicle obstacle detection device to which the present invention is applied.

As shown in FIG. 2, the vehicle obstacle detection device according to this embodiment includes a left front portion FL, a right front portion FR, and a left rear portion R of the vehicle.
4 ultrasonic sensors 2 provided on the L and right rear RRs, respectively
FL, 2FR, 2RL, 2RR and each of these ultrasonic sensors 2FL ~
The control unit 4 that sequentially drives the 2RR to detect obstacles existing in the front left, front right, rear left, and rear right of the vehicle, and the operating state of the device and the detection results of the obstacles by the control unit 4 are displayed. The display unit 6 is provided near the driver's seat for displaying.

On the display unit 6, a main switch 12 for disconnecting and connecting the power supply line for supplying power to the control unit 4 and a sound to inform the user when an obstacle is detected or an abnormality of the device is detected. A buzzer 14 for operating, a power indicator 16 that lights when the main switch 12 is turned on to display the operating state of the device, and a direction for displaying the direction of the vehicle when the obstacle is detected. Four
Individual indicator lights 18FL, 18FR, 18RL, 18RR are provided. Further, these four indicator lights 18FL to 18RR are provided at each corner portion of the display diagram schematically showing the vehicle, as shown in FIG. 3, so that the direction of the obstacle can be seen at a glance.

The ultrasonic sensors 2FL to 2RR are driven by drive signals from transmission circuits 32FL, 32FR, 32RL and 32RR, which will be described later, provided in the control unit 4, as shown in FIG. 4A. It is composed of an ultrasonic transducer 52 capable of transmitting and receiving ultrasonic waves, and a first amplifier circuit 54 which is connected to a signal path of a drive signal thereof and amplifies a vibration signal indicating a vibration state of the ultrasonic transducer 52. There is. The vibration signal amplified by the first amplifier circuit 54 is output to a signal switching circuit 36, which will be described later, provided in the controller 4.

Next, the control section 4 is composed of a microcomputer, and has a function as a first abnormality detecting means, an obstacle detecting means and a second abnormality detecting means in the present invention, and a control circuit. Receiving the burst signal for transmission output from 30, the above ultrasonic sensors 2FL to 2RR
Transmission circuits 32FL, 32 as driving means for driving
FR, 32RL, 32RR and the second amplifying the vibration signal output from the first amplifying circuit 54 in the ultrasonic sensors 2FL to 2RR.
The control circuit 30 converts the vibration signal SA amplified by the amplifier circuit 56 and the second amplifier circuit 56 into a digital signal SB.
The first detection circuit 58 to be input to each ultrasonic sensor 2FL
A signal switching circuit 36 for selectively inputting the vibration signal output from the first amplifier circuit 54 within 2RR to the second amplifier circuit 56.
And drive circuits 44, 46, 48FL to 48RR for driving the buzzer 14, the power indicator 16, and the indicator lamps 18FL to 18RR provided in the display unit 6, and the power supply voltage VB input via the main switch 12. Circuit 50 for converting the voltage into a constant voltage for driving the device and supplying the voltage to each of the above parts.
It consists of and.

The obstacle detecting device of the present embodiment thus constructed operates under the control of the control circuit 30, and the presence / absence of obstacles and obstacles in the respective parts of the vehicle provided with the ultrasonic sensors 2FL to 2RR. Along with detecting the distance to an object, the ultrasonic transducer 52 in the ultrasonic sensors 2FL to 2RR has a permanent abnormality such as a disconnection or a short circuit, and the ultrasonic transducer 52 in the ultrasonic sensors 2FL to 2RR has frozen or ultrasonic waves. Temporary abnormalities caused by adhesion of mud or wax to the vibrator 52 are detected, and the detection results are displayed to notify the vehicle driver.

The control process executed by the control circuit 30 to perform such a detection operation will be described below. First, FIG. 5 is a flowchart showing a control process periodically executed in the control circuit 30.

As shown in the figure, when this process is started,
First, at step 110, the value of the counter C, which is set to 0 when the power is turned on, is incremented. The counter C is used to sequentially change the vehicle position for detecting an obstacle. If C = 1, the left front FL is detected, and if C = 2, the right front RL is detected. Obstacle detection, if C = 3, obstacle detection of the left rear FR,
If C = 4, the obstacles in the right rear RR are set to be detected respectively. Therefore, in the following step 120, it is determined whether or not the value of the counter C exceeds 4, and if C> 4, the value of the counter C is set to 1 in step 130. That is, in steps 110 to 130, the value of the counter C is set to the values of 1 to 4 that determine the vehicle direction in which the obstacle is detected.

When the value of the counter C is set to any of 1 to 4 in this way, the process proceeds to the subsequent step 140 and the signal input to the second amplifier circuit 56 is changed to the counter C.
The signal switching circuit 36 is driven so that the vibration signal from the ultrasonic sensor 2 in the vehicle direction corresponds to the value of. Then, in the following step 150, the four transmission circuits 32FL-
Of the 32 RRs, the transmission circuit 32 that drives the ultrasonic sensor 2 in the vehicle direction corresponding to the value of the counter C has a predetermined time ΔT0.
Only the burst signal for transmission is output to drive the ultrasonic sensor 2.

Next, in step 160, step 150
The abnormality determination process for determining abnormality of the ultrasonic sensor 2 driven this time is executed based on the vibration signal output from the ultrasonic sensor 2 immediately after driving the ultrasonic sensor 2. This abnormality determination processing is executed as shown in FIG.

That is, first, at step 200, it is determined whether or not a predetermined time ΔT1 has passed after the driving of the ultrasonic sensor 2 is stopped, so that a predetermined time ΔT1 has passed after the driving of the ultrasonic sensor 2 is stopped. Waits for a predetermined time ΔT1 and then in step 210, the first detection circuit 58
It is determined whether or not the detection signal SB input from is at High level.

If the detection signal SB is at a low level, the process proceeds to the following step 220, and after the driving of the ultrasonic sensor 2 is stopped and a predetermined time ΔT1 has elapsed, it is further determined whether a predetermined time ΔT2 has elapsed. If the predetermined time ΔT2 has elapsed, it is determined that the ultrasonic sensor 2 is completely broken due to disconnection, short circuit, etc., and the permanent abnormality of the ultrasonic sensor 2 is stored in step 230. , The process ends.

On the other hand, in step 220, a predetermined time ΔT
If it is determined that 2 has not elapsed, the process proceeds to step 210 again and it is determined whether the detection signal SB is at the High level. In step 210, the detected signal S
If it is determined that B is at the high level, it is determined that no permanent abnormality has occurred in the ultrasonic sensor 2, the process proceeds to the subsequent step 240, and the ultrasonic sensor 2 is driven as in step 220 above. By waiting for the predetermined time ΔT2 to elapse by waiting for the predetermined time ΔT1 to elapse and then determining whether the predetermined time ΔT2 has elapsed.
When T2 has elapsed, it is determined again in step 250 whether the detection signal SB is at the high level.

If the detection signal SB is at a low level, the process proceeds to the following step 260, the driving of the ultrasonic sensor 2 is stopped, and a predetermined time (ΔT1 + ΔT2) elapses.
Further, it is judged whether or not a predetermined time ΔT3 has passed. If the predetermined time ΔT3 has passed, the ultrasonic sensor 2 is frozen.
When it is determined that a temporary abnormality has occurred due to adhesion of mud or wax, the temporary abnormality of the ultrasonic sensor 2 is stored in step 270, and the process ends.

On the other hand, in step 260, a predetermined time ΔT
When it is determined that 3 has not elapsed, the process returns to step 250 and it is determined whether the detection signal SB is at the High level. In step 250, the detection signal S
When it is determined that B is at the high level, it is determined that the ultrasonic sensor 2 is operating normally, the process proceeds to the subsequent step 280, the driving of the ultrasonic sensor 2 is stopped, and the ultrasonic sensor 2 is stopped for a predetermined time. After (ΔT1 + ΔT2) has passed, a predetermined time Δ
By determining whether or not T3 has elapsed, a predetermined time Δ
Waiting for T3 to elapse, and when a predetermined time ΔT3 elapses, the normality of the ultrasonic sensor 2 is stored in step 290, and then the process ends.

That is, first, when the ultrasonic sensor 2 is operating normally, as shown in FIG. 7A, even if the driving of the ultrasonic sensor 2 is stopped, the reverberation of the ultrasonic transducer 52 causes The vibration signal SA is input to the first detection circuit 58 for a predetermined time, and the detection signal SB becomes High level during that time. Also,
When the ultrasonic sensor 2 does not operate completely due to disconnection, short circuit, or the like, reverberation does not occur in the ultrasonic transducer 52 as shown in FIG. 7C, and therefore the vibration signal SA is transmitted to the first detection circuit 58. Is not input and the detection signal SB quickly becomes low level after the driving of the ultrasonic sensor 2 is stopped. On the other hand, when a temporary abnormality such as freezing occurs in the ultrasonic sensor 2,
As shown in (b), after the driving of the ultrasonic sensor 2 is stopped, the vibration signal SA is input to the first detection circuit 58 due to the reverberation of the ultrasonic vibrator 52, but the vibration of the ultrasonic vibrator 52 is suppressed. Therefore, the input time of the vibration signal SA becomes shorter than the normal time, and the detection signal SB becomes High level for a shorter time than the normal time after the driving of the ultrasonic sensor 2 is stopped.

Therefore, in the present embodiment, in the processing of steps 200 to 240 as the abnormality determining means, the detection signal SB is detected within the determination period ΔT2 from the time t1 to the time t2 after the driving of the ultrasonic sensor 2 is stopped. It is determined whether or not the vibration signal SA representing the reverberation of the ultrasonic transducer 52 is present by determining whether or not the high level is reached, and if the vibration signal is not present within this determination period ΔT2. If the permanent abnormality of the ultrasonic sensor 2 is detected, and if the permanent abnormality does not occur, the time t2 after the lapse of the determination period ΔT2 in the processing of steps 250 to 280 as the second abnormality determination means. From time t3 to time t3
By determining whether or not the detection signal SB has become High level within 3, it is determined whether or not the reverberation of the ultrasonic transducer 52 continues for a predetermined time as in the normal time, and the ultrasonic vibration When the reverberation of the child 52 does not continue for a predetermined time, a temporary abnormality of the ultrasonic sensor 2 is detected.

When the abnormality determining process is completed in this way, the process proceeds to step 170, and the obstacle detecting process for detecting the presence or absence of the obstacle and the distance to the obstacle is executed based on the detection signal SB. This obstacle detection processing is conventionally well-known processing, and as shown in FIG.
By inputting the reflection signal from the obstacle to the ultrasonic sensor 2 within the determination period from the time t4 when a predetermined time ΔT4 has elapsed after the elapse of T3 to the time t5 when a predetermined time ΔT5 has further elapsed after the elapse of T3, The ultrasonic transducer 52 vibrates,
When the detection signal SB is at a high level, it is determined that an obstacle exists, and if an obstacle exists, ultrasonic waves are transmitted (after the ultrasonic sensor 2 is driven), The distance to the obstacle is calculated based on the time until the detection signal SB becomes High level within the period ΔT5.

Finally, in step 180, a display process for displaying the detection result of the obstacle and the detection result of the temporary abnormality or the permanent abnormality of the ultrasonic sensor 2 on the display unit 6 is executed,
The process is once ended. The display process of step 180 is executed as shown in FIG.

That is, first, at step 310, it is judged whether the ultrasonic sensor 2 is normal or not from the judgment result of the abnormality judgment processing. If the ultrasonic sensor 2 is normal, step 32
At 0, it is determined whether or not an obstacle is detected by the obstacle detection processing. If no obstacle is detected, in step 330, all the obstacle display and abnormality display for the ultrasonic sensor 2 driven this time are stopped,
The process ends.

On the other hand, if it is determined in step 320 that an obstacle has been detected, in step 340, a display cycle for displaying the obstacle is set based on the distance to the obstacle, and step 350 is performed. At this set display cycle, the indicator lamp 18 corresponding to the ultrasonic sensor driven this time is blinked, and the buzzer 14 is synchronized with this blink cycle.
The obstacle display process is performed, and the process ends.

If it is determined in step 310 that the ultrasonic sensor 2 is not normal, step 360
Then, it is determined whether or not a temporary abnormality of the ultrasonic sensor 2 is detected in the abnormality determination process. Then, when the temporary abnormality of the ultrasonic sensor 2 is detected, the preset temporary abnormality display pattern is read in step 370, and the temporary abnormality is displayed in accordance with this display pattern in the next step 380. The temporary abnormality display process is executed, and the process ends.

The temporary abnormal display pattern is shown in FIG.
Immediately after the detection of the temporary abnormality, as shown in (b), the indicator lamp 18 and the power indicator 16 corresponding to the ultrasonic sensor in which the temporary abnormality is detected are blinked a plurality of times in a predetermined cycle (two blinks in the figure). Indicates that the operation is performed 5 times)
At the same time, the buzzer 14 is caused to ring in synchronization with this blinking cycle, and when such blinking operation is completed, the indicator lamp 18 corresponding to the abnormality sensor is turned on and the power indicator 16 is continuously blinked. It is set.

On the other hand, when it is determined in step 360 that the abnormality of the ultrasonic sensor 2 is not a temporary abnormality, that is, a permanent abnormality, the process proceeds to step 390 and a preset permanent abnormality is detected. The display pattern is read, and in the next step 400, temporary abnormality display processing for displaying a temporary abnormality according to this display pattern is executed, and the processing ends.

The permanent abnormality display pattern is shown in FIG.
As shown in (a), immediately after the detection of the permanent abnormality, only the indicator lamp 18 corresponding to the ultrasonic sensor in which the temporary abnormality is detected is blinked a plurality of times in the same cycle as in the case of the temporary abnormality, and the blinking is performed. It is preset so that the buzzer 14 sounds in synchronization with the cycle and then only the indicator lamp 18 corresponding to the abnormality sensor is turned on.

As described in detail above, in the obstacle detection apparatus of this embodiment, the ultrasonic transducer 5 of the ultrasonic sensor 2 is used.
2 Permanent abnormality due to disconnection, short circuit, etc., and ultrasonic transducer 52
The temporary abnormality due to the freezing or the adhesion of mud, wax, etc. to the ultrasonic transducer 52 is determined by the length of the detection signal SB immediately after the driving of the ultrasonic sensor 2 is stopped (that is, the reverberation time of the ultrasonic transducer 52). Therefore, the permanent abnormality and the temporary abnormality of the ultrasonic sensor 2 are detected individually.
Each is displayed so as to be distinguishable by the vehicle driver.

Therefore, according to the obstacle detecting apparatus of this embodiment, not only the permanent abnormality of the ultrasonic sensor 2 as in the conventional case but also the temporary abnormality of the ultrasonic sensor 2 can be accurately detected. The safety when the ultrasonic sensor 2 is abnormal can be improved. When the ultrasonic sensor 2 is permanently abnormal, the vehicle driver is urged to repair the ultrasonic sensor 2,
When there is a temporary abnormality, the vehicle driver can be informed of this fact and instructed to promptly restore the ultrasonic sensor 2 to normal operation.

Here, in the above embodiment, the ultrasonic sensor 2
Power indicator 16 in the display section 6 when the
By flashing, the permanent abnormality and the temporary abnormality of the ultrasonic sensor 2 are configured to be distinguishably displayed. For example, as shown in FIG. 10, the temporary abnormality of the ultrasonic sensor 2 is displayed on the display unit 6. A dedicated indicator light 20 for display is provided, and immediately after detecting a temporary abnormality of the ultrasonic sensor 2, this indicator light 2
0 is blinked a predetermined number of times at a predetermined cycle, and then the ultrasonic sensor 2
The temporary abnormality of the ultrasonic sensor 2 may be displayed by turning on the indicator lamp 20 until the temporary abnormality of No. 1 is resolved.

Next, in the above embodiment, the first amplifier circuit 54 in the ultrasonic sensor 2 and the second amplifier circuit 5 in the control unit 4 are used.
Based on the output signal (detection signal) SB from the first detection circuit 58 that detects the vibration signal SA amplified by
The reverberation state of the ultrasonic transducer 52 in the ultrasonic sensor 2 is detected, and when the reverberation time is shorter than the normal time, a temporary abnormality of the ultrasonic sensor 2 caused by freezing or dirt of the ultrasonic transducer 52 is detected. However, in order to detect such a temporary abnormality of the ultrasonic sensor 2, it is not always necessary to use the output signal from the ultrasonic sensor 2, and for example, a sensor that detects freezing or dirt of the ultrasonic transducer 52. By providing the above, it is possible to detect a temporary abnormality of the ultrasonic sensor 2. In this case, it is necessary to provide a special sensor for detecting freezing and dirt of the ultrasonic transducer 52, which causes a problem that the device configuration becomes complicated.

By the way, when the temporary abnormality of the ultrasonic sensor 2 is determined from the output signal (detection signal) SB from the first detection circuit 58 as in the above-described embodiment, the determination period Δ serving as the determination reference is provided. It is necessary to set T3 accurately. In other words, the first detection circuit 58 is provided with the ultrasonic transducer 52 in the ultrasonic sensor 2 in order to accurately detect the weak vibration of the ultrasonic transducer 52 due to the reflected wave from the obstacle. Since the output signals (vibration signals) SA from the first and second amplification circuits 54 and 56 for amplifying the vibration signals are input, when the ultrasonic sensor 2 is driven or when the reverberation occurs, the first detection circuit 58 amplifies the signals. Even at the end of reverberation when the vibration signal SA of the maximum level at which the circuit is saturated is input and the vibration of the ultrasonic vibrator 52 weakens, the ultrasonic vibrator 5
Since the detection signal SB representing the reverberation of 2 is output, the ultrasonic transducer 5 obtained based on this detection signal SB
The reverberation time of 2 does not differ greatly between when the ultrasonic transducer 52 is normal and when it is temporarily abnormal. Therefore, in the above embodiment, in order to accurately determine the temporary abnormality of the ultrasonic sensor 2, the determination period ΔT3, which is the determination criterion, is accurately set based on the reverberation time of the ultrasonic sensor 2 in the normal state. It is necessary to keep it.

Then, next, as a second embodiment of the present invention,
An obstacle detection device capable of detecting a temporary abnormality of the ultrasonic sensor 2 more simply and accurately than in the above embodiment will be described. The obstacle detection apparatus of the present embodiment can be achieved by configuring the ultrasonic sensors 2FL to 2RR as shown in FIG. 4B and executing the abnormality determination processing as shown in FIG.

That is, in the present embodiment, first, as shown in FIG. 4B, the vibration signals SC of the ultrasonic transducers 52 input to the first amplifying circuit 54 are input into the ultrasonic sensors 2FL to 2RR.
By providing the second detection circuit 60 for directly detecting the above, the detection signals SD of the ultrasonic sensors 2FL to 2RR are generated, and these detection signals SD are directly input to the control circuit 30.

Then, in the control circuit 30, the abnormality determination processing of step 160 shown in FIG. 5 is executed as shown in FIG. Hereinafter, this abnormality determination process will be described. As shown in FIG. 11, in the abnormality determination processing of the present embodiment, in step 500, after the driving of the ultrasonic sensor 2 is stopped, it is determined whether a predetermined time ΔT11 has elapsed, Predetermined time after stopping the driving of sensor 2 △
After waiting for T11 to elapse, when a predetermined time ΔT11 elapses, it is determined in the following step 510 whether or not the detection signal SD input from the ultrasonic sensor 2 driven this time is at the high level.

If the detection signal SD is at the low level, it is determined that the ultrasonic transducer 52 in the ultrasonic sensor 2 has a temporary abnormality such as freezing. Is stored, and the following step 53
Move to 0. If the detection signal SD is at high level, it is determined that the ultrasonic sensor 2 has no abnormality,
The process directly proceeds to step 530.

That is, the detection signal SD is a signal obtained by directly detecting the vibration signal SC from the ultrasonic transducer 52 in the ultrasonic sensor 2 driven this time by the second detection circuit 60, and the vibration before the detection. If the ultrasonic sensor 2 is normal, the signal SC once has a large amplitude immediately after the operation of the transmission circuit 32 as shown in FIG. 12A, and then the amplitude gradually decreases due to the resonance of the ultrasonic transducer 52. Transmission circuit 32
When the operation of is stopped, the amplitude increases again and then gradually decreases. Therefore, as shown in FIG. 12A, the detection signal SD when the sensor is normal is Hi when the ultrasonic sensor 2 is driven.
The level changes from the gh level to the low level, and after the driving of the ultrasonic sensor 2 is stopped, the level changes again to the high level due to the reverberation of the ultrasonic transducer 52.

On the other hand, when a temporary abnormality such as freezing occurs in the ultrasonic sensor 2, the vibration of the ultrasonic transducer 52 is suppressed, so that the vibration signal SC changes as shown in FIG. 12 (b). During the operation of the transmission circuit 32, it changes substantially in the same manner as the drive signal from the transmission circuit 32, and after the operation of the transmission circuit 32 is stopped, the vibration is quickly subsided. Therefore, the detection signal SD at the time of temporary sensor abnormality is the ultrasonic sensor 2 as shown in FIG.
When driving the ultrasonic sensor 2, it becomes High level, and when driving of the ultrasonic sensor 2 is stopped thereafter, it changes to Low level in a short time.

Therefore, in the second embodiment, the ultrasonic sensor 2 is processed by the processes of steps 500 to 520.
After the driving is stopped, the time ΔT11 until the detection signal SD becomes High level is set only in a normal state where the reverberation of the ultrasonic sensor 2 continues, and the above steps 500 to 52 are performed.
In the processing of 0, by determining whether the detection signal SD is at the High level at the time t11 when this time ΔT11 has elapsed,
The abnormality of the ultrasonic sensor 2 is determined.

Next, at step 530, the ultrasonic sensor 2
After the driving of the ultrasonic sensor 2 is stopped, it is judged whether or not a predetermined time ΔT1 has elapsed. After the driving of the ultrasonic sensor 2 is stopped, a predetermined time ΔT1 is waited. At, it is determined whether or not the detection signal SB input from the first detection circuit 58 is at the High level.

If the detected signal SB is at the low level, the process proceeds to the following step 550, and the driving of the ultrasonic sensor 2 is stopped and after a predetermined time ΔT1 has elapsed, whether a predetermined time ΔT2 has elapsed or not. If the predetermined time ΔT2 has elapsed, it is determined that the ultrasonic sensor 2 is completely broken due to disconnection, short circuit, etc., and the permanent abnormality of the ultrasonic sensor 2 is stored in step 560. Then, the process ends.

On the other hand, in step 550, a predetermined time ΔT
If it is determined that 2 has not elapsed, the process proceeds to step 540 again to determine whether the detection signal SB is at the High level. In step 540, the detection signal S
If it is determined that B is at the high level, it is determined that the ultrasonic sensor 2 has no permanent abnormality, the process proceeds to the subsequent step 570, the driving of the ultrasonic sensor 2 is stopped, and the predetermined time Δ After the elapse of T1, it is determined whether or not the predetermined time ΔT2 has further elapsed, and the process waits until the predetermined time ΔT2 elapses, and when the predetermined time ΔT2 elapses, the processing ends.

Note that this step 530 to step 570
The processing of step 500 to step 540 shown in FIG.
The processing is similar to that of the ultrasonic sensor 2
A permanent abnormality of is detected. As described above, in the obstacle detection device of the second embodiment, the waveform of the vibration signal SC before amplification output from the ultrasonic transducer 52 in the ultrasonic sensor 2 is the same as when the ultrasonic sensor 2 is normal. Paying attention to the large difference between the time of temporary abnormality and the ultrasonic sensor 2, a second detection circuit 60 for directly detecting the vibration signal SC is provided, and based on the detection signal SD by the second detection circuit 60. The temporary abnormality of the ultrasonic sensor 2 is detected.

Therefore, it is not necessary to accurately set the judgment time ΔT3 which is the judgment reference as in the above embodiment,
Only when the ultrasonic sensor 2 is normal, at time t11 when the detection signal SD becomes high level due to the reverberation of the ultrasonic transducer 52, it is determined whether or not the detection signal SD is high level. A temporary abnormality can be detected easily and surely.

In the second embodiment, the output from the ultrasonic transducer 52 in the ultrasonic sensor 2 is detected as it is to detect a temporary abnormality of the sensor. The output from the first amplifying circuit 54 having a low frequency may be input to the second detecting circuit 60. That is, when the ultrasonic transducer 52 is frozen or a foreign substance is attached to the ultrasonic transducer 52, if the vibration signal from the sensor gives a waveform significantly different from that in the normal state, as in the second embodiment. In addition, the temporary abnormality of the ultrasonic sensor 2 can be detected easily and surely.

[0061]

As described above in detail, according to the obstacle detecting device of the present invention, the ultrasonic transducer is frozen or ultrasonically vibrated as well as the permanent abnormality due to the disconnection or short circuit of the ultrasonic transducer. It is possible to detect a temporary abnormality caused by adhesion of mud or wax to the child.

Therefore, the safety can be further improved as compared with the conventional device. When the ultrasonic transducer is permanently abnormal, the user is urged to repair the ultrasonic transducer, and when the ultrasonic transducer is temporarily abnormal, the user is informed accordingly and the ultrasonic transducer is promptly repaired. You can also restore it.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of the present invention.

FIG. 2 is a block diagram showing the overall configuration of an obstacle detection device according to an embodiment.

FIG. 3 is an explanatory diagram illustrating an arrangement state of indicator lights and the like on the display unit 6.

FIG. 4 is an explanatory diagram showing internal circuits of ultrasonic sensors 2FL to 2RR.

FIG. 5 is a flowchart showing a control process periodically executed by the control circuit 30.

FIG. 6 is a flowchart showing an abnormality determination process executed in the control circuit 30.

FIG. 7 is an explanatory diagram illustrating a detection operation of a temporary abnormality of the ultrasonic sensor.

FIG. 8 is a flowchart showing a display process executed in the control circuit 30.

FIG. 9 is an explanatory diagram illustrating a display operation of a temporary abnormality and a complete abnormality of the ultrasonic sensor.

FIG. 10 is an explanatory diagram illustrating another configuration example of the display unit 6.

FIG. 11 is a flowchart showing an abnormality determination process of the second embodiment.

FIG. 12 is an explanatory diagram illustrating a detection operation of a temporary abnormality of the ultrasonic sensor according to the second embodiment.

[Explanation of symbols]

2FL, 2FR, 2RL, 2RR ... Ultrasonic sensor 4 ... Control part 6 ... Display part 14 ... Buzzer 16 ... Power indicator 18FL, 18FR, 18RL, 18RR, 20 ... Indicator light 3
0 ... Control circuit 32FL, 32FR, 32RL, 32RR ... Transmission circuit 44, 46, 48FL, 48FR, 48RL, 48RR ... Drive circuit 36 ... Signal switching circuit 52 ... Ultrasonic transducer 54 ...
1st amplifier circuit 56 ... 2nd amplifier circuit 58 ... 1st detection circuit 60
... Second detection circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masaru Nakamura, 1-1, Showa-cho, Kariya city, Aichi prefecture, Nihon Denso Co., Ltd. (72) Masato Okamoto, 1-cho, Toyota city, Aichi prefecture Toyota Motor Corporation Within

Claims (3)

[Claims] 1. An ultrasonic transducer capable of transmitting and receiving, driving means for outputting a driving signal to the ultrasonic transducer for a predetermined time to transmit an ultrasonic wave from the ultrasonic transducer, and the driving means. An amplifier circuit that is connected to the signal path to the ultrasonic vibrator and amplifies the vibration signal of the ultrasonic vibrator; a detection circuit that detects the vibration signal amplified by the amplifier circuit; Immediately after stopping the driving of the ultrasonic vibrator, it is determined whether or not a detection signal representing the reverberation after the driving of the ultrasonic vibrator is output from the detection circuit,
A first abnormality detecting means for detecting an abnormality of the ultrasonic transducer when the detection signal is not output; and a predetermined time after the driving of the ultrasonic transducer by the driving means is finished, Obstacle detection means for determining whether or not a detection signal representing vibration of the ultrasonic transducer caused by a reflected wave from the obstacle is output from the detection circuit, and detecting an obstacle when the detection signal is output In a vehicle obstacle detection device including: and, in addition to the first abnormality detection means, vibration of the ultrasonic transducer is suppressed by external force generated by freezing, dirt, etc. of the ultrasonic transducer itself. An obstacle detecting device, comprising: a second abnormality detecting means for detecting a temporary abnormality of the ultrasonic transducer. 2. A second detection circuit, wherein the second abnormality detecting means detects a vibration signal smaller than an output signal of the amplifier circuit, and the ultrasonic transducer output from the second detection circuit. The obstacle detection device according to claim 1, further comprising: a temporary abnormality determination unit that determines a temporary abnormality of the ultrasonic transducer based on a second detection signal that represents reverberation. 3. An abnormality display means for distinguishably displaying the abnormality of the ultrasonic transducer detected by the first abnormality detecting means and the second abnormality detecting means, respectively. The obstacle detection device according to claim 1 or 2.