JPH0526702B2 - - Google Patents

Abstract

PURPOSE:To prevent the repeated operation of an alarming device by continuing alarming for a preset time of period when the distance up to an obstacle goes below preset distance and an alarm is given once and subsequently even when the distance up to the obstacle is increased slightly further than the preset distance. CONSTITUTION:The distance up to an obstacle is detected by a sensor 13a and the detection signal is converted to a voltage signal by a processing circuit 14a. This voltage signal becomes lower than the reference voltage of an op amplifier 15a. In other words, when the distance up to the obstacle becomes lower than the preset distance, the op amplifier 15a output a signal. As a result, a light emitting diode 65a emits light and makes a display and operates a timer 30a. The timer 30a issues an output signal only for a fixed period of time and operates an alarming device 40. Once the alarming device 40 has been operated, the timer 30a operates the alarming device 40 for a fixed period of time. Then, even when the distance up to the obstacle is varied slightly approximately for the preset distance, the alarming device 40 does not perform the repeated operation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device that warns when an obstacle exists around a vehicle.

[Conventional technology]

In this type of vehicle surroundings monitoring device, an alarm device is continuously activated when an obstacle exists around the vehicle.

In response to this, the applicant proposed in Japanese Patent Application No. 59-9047 (Japanese Unexamined Patent Publication No. 60-152969) that an alarm device is activated only for a certain period of time.

According to this, when you want to bring your vehicle close to an obstacle, such as when parking in a garage, if a warning is issued for a certain period of time, the warning will not be issued after that.
It is possible to prevent the driver from feeling that the warning is noisy.

[Problem that the invention seeks to solve]

However, even if the vehicle is equipped with a vehicle surroundings monitoring device that issues an alarm for a certain period of time, the alarm may be issued repeatedly if the vehicle is stopped exactly at the location where the alarm is not issued. For example, the distance between the obstacle detection sensor and the obstacle is 20
If the vehicle is stopped exactly 20 cm away from the vehicle, an alarm will be issued for a certain period of time if the distance is within 20 cm. Then, for some reason, the vehicle moves slightly, and the distance between the sensor and the obstacle becomes 20.5 cm.Furthermore, the vehicle moves again, and the distance increases.
When it reaches 20cm, a warning will be issued again. This degree of vehicle movement is required for vehicles with automatic transmissions.
It easily occurs when the vehicle's attitude changes when the shift lever is operated between the drive or reverse position and the neutral or parking position, and it can also occur due to unevenness on the road surface.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to prevent repeated warnings from being issued in a vehicle surroundings monitoring device in which warnings are issued only for a certain period of time.

[Means for solving problems]

Therefore, in the present invention, once a warning is issued, even if the distance to the obstacle becomes larger than the distance at which the warning is issued, if the distance is only a small amount, the warning is initially issued as if the distance had not increased. It is characterized by continuing the signal state when it was issued.

Specifically, the present invention includes a detection means installed on a vehicle body that emits a detection signal when the distance to an obstacle is smaller than a set distance; a timer that emits a time signal for a certain period of time after the time has passed, and an alarm that operates upon receiving the time signal from the timer and issues an alarm;
In the vehicle surroundings monitoring device, the detection means has a set distance, so that when the detection means emits a detection signal, the detection signal continues to be emitted even if the distance to the obstacle becomes larger than the set distance. Alternatively, the present invention is characterized in that a changing means is provided for changing the signal representing the distance to the obstacle in the detecting means by a predetermined value.

[Effect]

While the distance from the sensor of the detection means to the obstacle is greater than a predetermined set distance, the detection means does not generate a detection signal and no alarm is issued. When the vehicle and the obstacle approach and the distance to the obstacle becomes smaller than the set distance, the detection means issues a detection signal and a warning is issued for a certain period of time.

In this way, once the alarm is issued, the vehicle will stop near the position where the distance to the obstacle is the set distance, and then for some reason the vehicle will move slightly in the direction of changing the distance to the obstacle. However, even if the distance to the obstacle changes around the set distance, the changing means allows the detection signal to continue being emitted from the detection means, so at this time the alarm is activated repeatedly. It never happens. In other words, a warning is issued for a certain period of time from the time when the distance to the obstacle first becomes smaller than the set distance, and thereafter no warning is issued.

The changing means increases the set distance in the detecting means by a predetermined value, or decreases the signal representing the distance to the obstacle in the detecting means by a predetermined value.

However, if the distance between the vehicle and the obstacle is large, the detection means will no longer generate a detection signal, and the next warning will be issued when the distance to the obstacle becomes smaller than the set distance.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a first embodiment of the present invention, and in this embodiment, four detection means are provided. However, each detection means 10a to 10d
Since the configurations of the detection means 10a are all the same, the detection means 10a
Only the configuration of the other detection means 10b to 10b is shown in detail.
The configuration of 10d is omitted from illustration.

One detection means 10a includes a sensor 13a, and the sensor 13a is connected to a processing circuit 14a. In this case, the sensor 13a is an ultrasonic transmitter/receiver, and generates pulsed ultrasonic waves in a predetermined direction at certain time intervals according to a signal from the processing circuit 14a, and the ultrasonic waves strike an obstacle. It receives the reflected signal and sends the received signal to the processing circuit 14a. The processing circuit 14a then obtains a voltage signal proportional to the time from transmission to reception of the ultrasound. Since the time from transmission to reception of ultrasonic waves is proportional to the distance to the obstacle, the voltage signal output from the processing circuit 14a is proportional to the distance to the obstacle.

FIG. 2 schematically shows a plan view of the vehicle, and as is clear from this figure, each detection means 10
Sensors 13a to 13d of a to 10d are arranged at the four corners of the vehicle body. And each sensor 13a~
13d sets the diagonally front or diagonally rear side of the vehicle as a monitoring area, and transmits and receives ultrasonic waves toward obstacles existing in that area.

In FIG. 1, reference numeral 15a is an operational amplifier connected to form a comparator, and its inverting input receives a voltage signal from the processing circuit 14a via a resistor 16a, and its non-inverting input receives a resistor. A reference voltage is input from potentiometer 61 via 17a. Therefore, the operational amplifier 15a is connected to the processing circuit 14.
While the voltage signal from the processing circuit 14a is higher than the reference voltage, a signal with a logic level of "0" is output, but when the voltage signal from the processing circuit 14a becomes lower than the reference voltage, a signal with a logic level of "0" is output. 1” signal is output. Here, logic levels "1" and "0" mean that the voltage level is "higher" than a predetermined voltage level,
Each means being in a "low" state. It will be used in the same way below. Since the output of the operational amplifier 15a becomes a detection signal of the detection means 10a, the reference voltage corresponds to the set distance. The set distance in this case is, for example, about 20 cm.

Further, a potentiometer 51a and a resistor 52a, which constitute the changing means 50a, are connected between the output of the operational amplifier 15a and the non-inverting input, so that the output voltage of the operational amplifier 15a becomes equal to the voltage level of the non-inverting input of the operational amplifier 15a. It's starting to have an impact. That is, the voltage level input to the non-inverting input of the operational amplifier 15a is made higher by a predetermined voltage when the output of the operational amplifier 15a is logic "1" than when the output of the operational amplifier 15a is logic "0". As a result of increasing the voltage in this way, the set distance is increased. In this case, the predetermined voltage is set to a value that increases the set distance by 1 cm, for example. To be more specific, when the operational amplifier 15a is outputting a logic "0" signal, the voltage level input to the non-inverting input of the operational amplifier 15a is a voltage slightly lower than the above-mentioned reference voltage. Therefore, when setting the reference voltage, it is necessary to take this decrease into account.

The output of the operational amplifier 15a is connected to the cathode of the light emitting diode 65a via the inverting circuit 64a, and the anode of the light emitting diode 65a is connected to the resistor 6.
It is connected to the positive power supply via 6a. Further, the output of the operational amplifier 15a is connected to a timer 30a made of a monostable circuit, and the output of the timer 30a is connected via an OR gate 62 and an inverting circuit 63 to one end of an alarm 40 made of a buzzer. The other end of the alarm device 40 is connected to a positive power source. Therefore, while a logic "0" signal is being output from the operational amplifier 15a, a logic "1" signal, that is, a voltage equal to the positive power supply, is applied to the cathode of the light emitting diode 65a, so that the light emitting diode 65a is No light is emitted, the timer 30a does not operate, and a logic "1" signal, that is, a voltage equal to the positive power supply, is applied to one end of the alarm 40, so the alarm 40 also does not operate. On the other hand, when the operational amplifier 15a outputs a logic "1" signal, a logic "0" signal is applied to the cathode of the light emitting diode 65a. In other words, since no voltage is applied, the light emitting diode 6
5a emits light. Also, at that time, the timer 30a
outputs a logic "1" signal for a certain period of time, so one end of the alarm 40 outputs a logic "0" signal for a certain period of time.
signal is applied, that is, no voltage is applied,
The alarm 40 is activated for a certain period of time.

The changing means 50b to 50d, light emitting diodes 65b to 65d, and timers 30b to 30d connected to the other detecting means 10b to 10d have the same configurations as described above. In addition, each timer 30
Since the outputs of a to 30d are connected to one inverting circuit 63 and one alarm 40 via one OR gate 62, any one of the detection means 10a to 10
When a detection signal of logic "1" is output from d, the alarm device 40 is activated for a certain period of time to issue an alarm.

FIG. 3 shows the configuration of the display section 80, and as is clear from this, each light emitting diode 65a
-65d are arranged so that each sensor 13a-13d corresponds to the picture showing the plane of the vehicle, and the alarm 40 is also attached adjacent thereto.

Next, the action will be explained.

If there are no obstacles approaching the four sides of the vehicle, none of the detection means 10a to 10d will generate a detection signal, and the light emitting diodes 65a to 65d will not activate the alarm 40.
is not activated either.

Now, for example, when an obstacle approaches the diagonally right front of the vehicle and the distance to the sensor 13a becomes smaller than the set distance, the detection means 10a generates a detection signal, that is, a logic "1" signal is output from the operational amplifier 15a. is output, causing the light emitting diode 65a to emit light, and at the same time operating the alarm 40 for a certain period of time. This allows the vehicle occupant to know that there is an obstacle approaching diagonally to the right of the vehicle. After that, the detection signal continues to be generated and the light emitting diode 65a continues to emit light as long as the obstacle does not move away. However, the alarm 40 stops operating after a certain period of time, so that the occupant does not feel the alarm is noisy.

After that, when an obstacle approaches the diagonally right rear side of the vehicle, the detection means 10c generates a detection signal. Therefore, the light emitting diode 65c emits light, and the alarm 40 is activated again for a certain period of time to notify the occupant that there is a new obstacle approaching. In this way, the alarm device 40 is activated and a warning is issued for a certain period of time each time there is an obstacle approaching in each direction, so that the occupant can distinguish and recognize the obstacles.

By the way, as mentioned above, when an obstacle diagonally to the right of the vehicle approaches the set distance and a warning is issued,
If the vehicle is stopped at that moment, the detection means 1
A detection signal continues to be generated from 0a. At this time,
When the vehicle moves slightly away from the obstacle for some reason, the voltage signal output from the processing circuit 14a decreases a little and becomes lower than the reference voltage. However, at this time, the operational amplifier 15a has already outputted a signal of logic "1", and the operational amplifier 15a has already output a signal of logic "1".
Since the voltage input to the non-inverting input of the operational amplifier 14a is increased by a predetermined voltage, if the amount of decrease in the voltage signal from the processing circuit 14a is below the predetermined voltage, the operational amplifier 1
5a continues to generate a logic "1" signal, that is, a detection signal. Therefore, the light emitting diode 65a continues to emit light, and the alarm 40 is not activated until a certain period of time has elapsed after the obstacle first approaches the set distance.

In this way, the vehicle can be stopped at the position where the alarm was issued, and then the shift lever of the automatic transmission can be operated from this position between the drive position or reverse position and the neutral position or parking position, or when the vehicle is stopped at the position where the warning is issued. Even if the vehicle moves slightly due to the movement, if the change in the distance between the sensor 13a and the obstacle due to the effect is within a predetermined range,
The alarm is not issued every time the vehicle moves, and it is possible to avoid making the occupants feel the alarm is noisy or making them think that another obstacle is approaching.

However, after that, if the vehicle and the obstacle are far apart, the voltage input to the non-inverting input of the operational amplifier 15a is again set to the reference voltage and returns to the initial state.

FIG. 4 is a block diagram showing a second embodiment of the present invention, in which the detection means 10 is mainly composed of a microcomputer. Further, FIG. 6 shows signal waveforms at each part in FIG. 4, and will be described below with reference to FIG. 6.

Here, 21 is a transmitter that transmits ultrasonic waves of about 40 kHz in a predetermined direction around the vehicle, for example toward the rear of the vehicle. The transmitter 21 is activated by receiving the output signal _S1 of the monostable circuit 23, and the monostable circuit 23 is activated by the output signal S1 of the monostable circuit 23.
For a certain period of time after receiving the transmission start command signal S ₀ from 5.
The signal S ₁ is output only for T ₀ .

In FIG. 4, 22 is a receiver which receives the ultrasonic wave having the same frequency as that transmitted by the transmitter 21, and converts the portion above a predetermined level into a logical signal. Then, the receiver 22 adjusts its reception direction, and
Ultrasonic waves transmitted by a transmitter 21 and reflected by obstacles existing within a predetermined area are received.

The signal S ₄ obtained at the receiver 22 is sent to one input terminal of a NAND gate 26 , and the gate signal S ₂ from the microcomputer 25 is sent to the other input terminal of the NAND gate 26 .
The gate signal _S2 is configured to rise _T1 hours after the transmission start command signal _S0 is generated, and fall _T2 hours after the transmission start command signal S0 is generated. Therefore, the electrical signal S ₄ from the receiver 22 is taken into the next stage circuit only while the gate signal S ₂ is at logic level "1", and the electrical signal S 4 from the receiver 22 is received by the receiver 22 during the time T ₁ . digitized signals or those converted into electrical signals by the receiver 22 after T ₂ hours have elapsed are not captured. That is, the signal within T ₁ time is not reflected by an obstacle,
The signal is excluded as having directly propagated from the transmitter 21 to the receiver 22, and the signal after _T2 time is excluded as being a reflected wave from an obstacle located further away than the set distance.

Further, the output signal of the NAND gate 26 is sent to one input terminal of the NAND gate 28. This NAND gate 28 is combined with the NAND gate 27 to form a flip-flop FF, and when a logic "0" signal is output from the NAND gate 26, a logic "1" signal _S5 is output from the NAND gate 28, which is flipflop FF
It is now held at and,
This signal S ₅ is sent to the microcomputer 25 . On the other hand, one input terminal of the NAND gate 27 receives a flip-flop FF clear signal from the microcomputer 25 via the inverting circuit 24.
When S ₃ is sent and clear signal S ₃ occurs,
The output signal _S5 from the NAND gate 28 is logic "0"
The state in which the signal is held by the flip-flop FF is cleared. The clear signal _S3 is generated immediately after the gate signal _S2 falls from "1" to "0".

The microcomputer 25 generates each signal S ₀ , S ₁ , S ₃ at the timing mentioned above, and the NAND gate 2
The output signal _S5 from the flip-flop FF is taken in by the program as the output signal of the flip-flop FF. Then, when the output signal _S5 is processed and it is determined that there is an obstacle within the set distance, an activation signal _S6 is sent to the timer 30 consisting of a monostable circuit.
The alarm 40 is activated for a certain period of time.

FIG. 5 shows the program contents of the microcomputer 25.

When this program is started, first, step 101 is processed, and each part of the microcomputer 25 is initialized. And then step
Processes from 102 onwards are executed repeatedly.

In step 102, a transmission start command signal S ₀ is generated, the monostable circuit 23 is then generated a signal S ₁ for time T ₀ , and the transmitter 21 is caused to transmit a pulsed ultrasonic wave for time T ₀ . Next, in step 103, it is determined whether the timer counter CT has reached T1 _or more. The timer counter CT is cleared and started by the initialization in step 101, and then
T After ₁ hour has passed, the count value of timer counter CT is
If T is greater than or equal to ₁ , proceed to step 104, where
The gate signal _S2 is set to logic "1" to open the NAND gate 26. Thereafter, in step 105, wait for the elapse of time _T2 , and when time _T2 has elapsed, in step 106, the gate signal _S2 is set to logic "0", and the NAND gate 2
6 is set to the gate open state, but before that, in steps 121-124, time _T2 is determined.

First, in step 121, it is determined whether flag F is set. Flag F is set and is used to remember that the presence of an obstacle was confirmed during the previous processing. If flag F is set, an affirmative judgment is made in step 121, and in step 122, t is determined to be a predetermined value. If the value α is set and the flag F is not set, a negative determination is made in step 121, and in step 123, t is set to “0”.
It is said that Then, in step 124, time T ₂ is
It is determined by t ₀ +t. Here, t ₀ is determined to match the time required for the transmitted ultrasonic wave to be reflected by the obstacle and received when the obstacle is exactly at the set distance, and the predetermined value α is ,
It is determined to correspond to the time it takes for an ultrasonic wave to travel back and forth over a short distance, for example, 1 cm.

Next, in step 107, a clear signal _S3 is generated to clear the flip-flop FF.
The flip-flop FF is returned to its initial state. Then, in step 108, the output signal _S5 of the flip-flop FF is taken in, and it is determined whether the signal _S5 is at logic "1". this signal
_S5 is the signal _S4 output from the receiver 22 held by the flip-flop FF while the NAND gate 26 is in the gate open state, and if this signal _S5 is logic "1", the setting is This indicates that there is an obstacle within the distance, and if the logic is "0", it indicates that there is no obstacle within the set distance. Therefore, when step 108 is answered in the affirmative, a logic "1" signal is output as the signal _S6 in step 109, and when step 108 is answered in the negative, a logic "1" signal is output as the signal _S6 in step 110. Outputs a “0” signal. timer 30
is activated when the signal S ₆ is a logic ``1'' and deactivated when the signal S 6 is a logic ``0''. During the timer 30's operation, the timer 30 sends an activation signal to the alarm 40 for a certain period of time, and issues an alarm to the occupants.

When step 109 is processed, step 125
At step 126, a flag F is set to remember that an obstacle has been detected and a warning has been issued, and when step 110 has been processed, a flag F is reset at step 126 to remember that an obstacle has been detected and a warning has been issued. Remember what happened.

Next, in step 111, the process waits for time _T3 to elapse, and then proceeds to step 112, where a timer counter CT for measuring time is cleared.
After this, the process of step 102 is performed again, and finally,
Ultrasonic waves are transmitted by the transmitter 21 every time _T3 .

In FIG. 6, two transmissions of ultrasonic waves by the transmitter 21 are shown. During the first transmission, an obstacle is detected, a signal _S4 is obtained from the receiver 22, and a signal S4 is sent to the microcomputer 25. ₅ is sent, the gate signal S ₂ when the ultrasound is sent next
The gate opening time T ₂ is slightly shorter than the initial time t
It has only been longer. As a result, the vehicle is stopped at the moment when the obstacle is detected and the alarm is issued, and even if the vehicle subsequently moves slightly, for example by 1 cm, in a direction that increases the distance between the obstacle and the obstacle, the setting continues. The presence of an obstacle within the distance can be detected, and it is possible to prevent a warning from being issued every time the vehicle moves slightly.

However, if the vehicle and the obstacle become far apart after that, the gate opening time _T2 is returned to the original time.

In the flowchart of FIG. 5, the processes in steps 121 to 126 correspond to the modification means of the present invention.

Furthermore, FIG. 7 is a block diagram showing a third embodiment of the present invention. In this embodiment, the detection means 1
Although there is only one 0, its configuration is the same as that explained in FIG.

Here, a changing means 50 is connected between the output and the inverting input of the operational amplifier 15. The changing means 50 includes an NPN transistor 53, a resistor 54,
55, and while the operational amplifier 15 is outputting a logic "0" signal, the transistor 53 is non-conducting, so at this time it has no effect on the voltage of the inverting input, but the operational amplifier 15 outputs a logic "0" signal. "1"
When the signal , the transistor 53 becomes conductive and slightly lowers the voltage at the inverting input.

Therefore, while the operational amplifier 15 is not generating a logic "1" signal, that is, a detection signal, and no alarm is issued, the distance signal output from the processing circuit 14 of the detection means 10 is directly transmitted to the operational amplifier 15. is input to the inverting input of the operational amplifier 15.
is compared with the reference voltage of the non-inverting input. and,
When an obstacle approaches the vehicle and the voltage of the distance signal gradually decreases until the distance to the obstacle reaches the set distance and the voltage of the distance signal becomes lower than the reference voltage, the operational amplifier 15 changes to logic "1". A signal is output, and the timer 30 operates the buzzer 40 for a certain period of time. In other words, give an alarm.

In this way, when the operational amplifier 15 outputs a signal of logic "1", the voltage from the processing circuit 14 is reduced by the changing means 50, so that even if the distance to the obstacle increases slightly, , the operational amplifier 15 continues to output a logic "1" signal.

Therefore, in this embodiment, as in the above two embodiments, even if the vehicle is stopped at the moment the alarm is issued and the vehicle moves slightly for some reason, the alarm will not be issued repeatedly. It will never be done.

[Effect of idea]

As described above, according to the present invention, once the distance to the obstacle becomes smaller than the set distance and a warning is issued, even if the distance to the obstacle becomes larger than the set distance thereafter, the alarm will be issued even if the distance to the obstacle becomes larger than the set distance. If so, the detection signal will continue to be generated as if the distance had not increased, so even if the vehicle is stopped at a position where the distance to the obstacle is close to the set distance, and the vehicle moves slightly at that position, The warning is issued only for an initial fixed period of time, and is not repeated thereafter, so that the vehicle occupants do not feel the alarm is noisy.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the first embodiment of the present invention, Fig. 2 is an explanatory diagram showing the mounting position of the sensor in the first embodiment, and Fig. 3 is the configuration of the display section in the first embodiment. 4 is a block diagram showing the second embodiment of the present invention, and FIG. 5 is a block diagram showing the second embodiment of the present invention.
FIG. 6 is a flowchart showing the program contents of the microcomputer of the embodiment, FIG. 6 is a time chart showing signal waveforms of each part in FIG. 4, and FIG. 7 is a block diagram of a third embodiment of the present invention. 10...detection means, 30...timer, 40...
Alarm, 50... Change means.

Claims (1)

[Claims] 1. A detection means installed on the vehicle body that emits a detection signal when the distance to the obstacle is smaller than a set distance; , a timer that emits a timed signal for a certain period of time, and an alarm that operates in response to the timed signal from the timer and issues an alarm. changing means for changing the set distance in the detecting means or the signal representing the distance to the obstacle in the detecting means by a predetermined value so that the detection signal continues to be emitted even if the distance to the obstacle becomes larger than the set distance; A vehicle surroundings monitoring device characterized by being provided with.