JP2807120B2 - Ultrasonic sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic wave which emits an ultrasonic wave into a monitored space, detects a reflected wave from the object in the monitored space, and detects movement or presence of the object in the monitored space. It concerns a sensor.

[0002]

2. Description of the Related Art An ultrasonic sensor of this type transmits an ultrasonic wave of a predetermined frequency into a monitoring space using an ultrasonic transducer,
The movement or presence of the object is detected by receiving the reflected wave from the object by the ultrasonic vibrator. Here, in order to detect the movement of the object, the movement of the intruding object is detected based on the Doppler signal included in the reflected wave, and to detect the presence of the object, the ultrasonic pulse is transmitted from the transmitter. To detect the presence of the object in the monitoring space by receiving the reflected wave from the object by the receiver. By alternately switching between these detection methods, before and after the movement of the object is detected by the movement detection method, the reflection patterns from the object by the presence detection method are stored in chronological order, and the two reflection patterns are compared. This is to determine the presence or absence of an object in the monitoring space.

FIG. 2 shows an example of the configuration. In this conventional example (Japanese Patent Application No. 2-198174), an oscillation signal oscillated from an oscillator 1 is transmitted from an ultrasonic transmitter 3 via a transmission circuit 2. The ultrasonic wave reflected by the moving object is received by the ultrasonic wave receiver 4, and the received signal is amplified by the amplifier circuit 6 via the transmission-specific switching circuit 5. This signal is mixed with the transmission signal by the mixer 7, and the Doppler signal included in the reflected wave is detected by the detection circuit 8,
The signal is amplified by the amplifier circuit 9 and input to the detection determination circuit 12. The detection judging circuit 12 outputs a detection signal when detecting the Doppler signal.

[0004] Next, the timer circuit 10 switches to the presence detection method described below at every predetermined time. When the operation time of the movement detection method reaches a predetermined time, the timer circuit 10 sends a signal to the transmission method determination circuit 13 to change to the presence detection method. The transmission circuit 2 receives the signal from the transmission method determination circuit 13 and transmits the signal oscillated from the oscillator 1 to the ultrasonic transmitter 3 as a tone burst wave of a pulse train suitable for the presence detection method. The transmission system determination circuit 13 sends a signal indicating that the transmission system has been switched to the transmission-specific switching circuit 5. The tone burst wave generated by the transmission circuit 2 is transmitted from the ultrasonic transmitter 3 as an ultrasonic pulse train, and each ultrasonic pulse is reflected by an object in the monitoring space and transmitted to the ultrasonic receiver 4. Received. This received signal passes through the transmission-specific switching circuit 5 and is transmitted to the amplification circuit 1.
1 and is detected by the detection circuit 14. The reflection pattern of the detected waveform obtained at this time is stored in the storage circuit 17 or 18 in time series. Then, the reflection patterns stored in the storage circuits 17 and 18 are compared in time series by the comparison circuit 19. The presence / absence detection signal is output by the detection / judgment circuit 12 in accordance with the result of the comparison.

[0005]

In the conventional example described above, it is assumed that when a person is already in the monitored area , another person enters the monitored area and leaves.
I didn't.

The present invention has been made in view of such a point, and an object of the present invention is to provide an ultrasonic sensor using both a movement detection method and a presence detection method when an intruding object is already present. Even if an intruding object enters and exits, it does not malfunction.

[0007]

According to the present invention, in order to solve the above-mentioned problems, as shown in FIG. 1, an ultrasonic wave is driven in a monitoring space by being driven by a transmission signal output from an oscillator 1. And a receiver 4 for receiving a reflected wave from an object existing in the monitoring space, and a frequency generated in a received signal by the Doppler effect when the object moves. The first detection method detects a shift component and detects movement of an intruding object, and transmits an ultrasonic pulse from the transmitter 3 and receives a reflected wave from the object by the receiver 4. Means for alternately switching between a second detection method for detecting the presence of an object in the monitoring space and a second detection method at predetermined time intervals,
Storage circuit 1 that stores in time series the detection signal of the second detection method before the detection signal of the first detection method is first obtained
7 and the detection signal of the second detection method after the detection signal of the first detection method is obtained, and the detection signal of the first detection method is obtained.
A second storage circuit 18 that stores the data in time series each time the first and second storage circuits 17 and 18 are compared, and a first comparison circuit 19 that compares the stored contents of the first and second storage circuits 17 and 18 with each other. When the first comparison circuit 19 detects the presence of an intruding object, the ultrasonic sensor includes a detection determination circuit 12 that determines that an intruding object exists when the results do not match.
A second comparator circuit 15 the detection signal in the detection method compares the storage content of the first and second memory circuits 17 and 18 again in the event of, first及by the second comparator circuit 15
And the storage contents of the second storage circuits 17 and 18 do not match.
When the comparison result is obtained, a delay circuit 16 for extending the end of the detection signal for a predetermined time, and again within this extension time,
A detection circuit that does not terminate the detection signal until the contents of the first and second storage circuits and match when the detection signal of the first detection method is obtained; is there.

[0008]

According to the ultrasonic sensor of the present invention, the movement detection method using the Doppler effect and the presence detection method using the detection of the presence or absence of reflection of the ultrasonic pulse are alternately switched, and the movement of the object is detected by the movement detection method. Before and after the detection, the reflection patterns from the object by the presence detection method are stored and compared, and when the reflection patterns do not match, it is detected that an intruding object is present. When the detection signal of the movement detection method is generated after the presence of the intruding object is detected, the reflection patterns are compared again, and the reflection patterns do not match in the same manner as when the presence of the intruding object is detected. When the comparison result is obtained, the end of the detection output is extended for a predetermined time. If a detection signal by the movement detection method is generated within this extension time, the detection signal obtained in the second storage circuit 18 by the presence detection method has the same content as the detection signal stored in the first storage circuit 17. The detection output is not terminated until becomes. Thereby, even when the movement of another intruding object is detected when the intruding object already exists, the remaining intruding object is not erroneously recognized as a stationary object.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention. The oscillation signal oscillated from the oscillator 1 is transmitted from the ultrasonic transmitter 3 via the transmission circuit 2. The ultrasonic wave reflected by the moving object is received by the ultrasonic wave receiver 4, and this received signal passes through the transmission-specific switching circuit 5 and the amplification circuit 6.
Amplified by This signal is mixed with the transmission signal by the mixer 7, and the Doppler signal included in the reflected wave is detected by the detection circuit 8, amplified by the amplification circuit 9, and input to the detection determination circuit 12. The detection judging circuit 12 outputs a detection signal when detecting the Doppler signal.

Next, the timer circuit 10 switches to the presence detection method described below at predetermined time intervals. When the operation time of the movement detection method reaches a predetermined time, the timer circuit 10 sends a signal to the transmission method determination circuit 13 to change to the presence detection method. The transmission circuit 2 receives the signal from the transmission method determination circuit 13 and sends the signal oscillated from the oscillator 1 to the ultrasonic transmitter 3 as a tone burst wave suitable for the presence detection method. The transmission system determination circuit 13 sends a signal indicating that the transmission system has been switched to the transmission-specific switching circuit 5. The tone burst wave generated by the transmission circuit 2 is transmitted from the ultrasonic transmitter 3 as an ultrasonic pulse train, reflected by an object in the monitoring space, and received by the ultrasonic receiver 4. This received signal is amplified by the amplifier circuit 11 via the transmission-specific switching circuit 5, and is detected by the detection circuit 14.
Is detected by Here, the first storage circuit 17 stores the detection signal of the presence detection method before the detection signal of the movement detection method is obtained in chronological order, and the second storage circuit 18 stores the detection signal of the movement detection method. The detection signals of the presence detection method after the detection signals are obtained are stored in chronological order.
The comparison circuit 19 includes the first and second storage circuits 1
7 and 18 are compared, and when the comparison results obtained by the comparison circuit 19 do not match, the detection determination circuit 12
It is determined that an intruding object exists. In such an ultrasonic sensor, when the detection signal of the movement detection method is generated after the presence detection is recognized by the comparison circuit 19, the storage contents of the first and second storage circuits 17 and 18 are again updated. A comparison circuit 15 for comparison is provided. When a comparison result similar to that of the existing object obtained by the above-described comparison circuit 19 is obtained by the comparison circuit 15, the end of the detection output is extended by the delay circuit 16 for a predetermined time. If the detection signal of the movement detection method is obtained again within this extension time, the first storage circuit 17
The detection output is not terminated until it is determined that the content of the second storage circuit 18 matches the content of the second storage circuit 18.

FIG. 3 is an operation explanatory diagram showing an operation example of this embodiment. In the figure, R is a private room, D is a door, and S is a private room R
Is an ultrasonic sensor mounted on the ceiling of the vehicle. Z is the monitoring space of the sensor. When the door is opened as shown in FIG. 3A and the human body A enters the private room R as shown in FIG. 3B and sits as shown in FIG. When the intrusion of A is detected, the reflection pattern of the detection signal by the presence detection method before the intrusion is stored in the first storage circuit 17, and the reflection pattern of the detection signal by the presence detection method after the intrusion is the second. It is stored in the storage circuit 18. In the comparison circuit 19, the first and second storage circuits 1
Because the reflection patterns stored in 7, 18 are different,
Detects the presence of an intruding object and continues to output detection output. Here, when the human body B opens the door as shown in FIG. 3D, enters the private room R as shown in FIG. 3E, and goes out as shown in FIG. Intrusion of the human body B is detected by the movement detection method. At this time, if the human body A is stationary as shown in FIG. 3 (g), a detection signal by the movement detection method can not be obtained . However, in the present invention, the comparison circuit 15 is provided, and the first and second detection circuits are provided. The reflection patterns stored in the storage circuits 17 and 18 are compared, and when the same comparison result as in FIG. 3C is obtained, the end of the detection output is extended by the delay circuit 16 for a predetermined time. If the human body A moves again within this extended time and a detection signal is obtained by the movement detection method, the determination circuit 20 determines whether the reflection pattern stored in the first and second storage circuits 17 and 18 is correct. The detection output is not terminated until a match is detected. Therefore, the detection output does not end until the person A leaves, and FIG.
As shown in (h), the human body A goes out of the private room R, and FIG.
The detection output ends only when returning to the initial state as shown in (i).

Here, when the detection output from the ultrasonic sensor S is generated, the lighting equipment and the air conditioning equipment related to the private room R start operating, and when the detection output is completed, the operation of these equipment is stopped by a predetermined OFF delay. If the human body A enters the private room R and exits, these devices continue to operate, and the human body B intrudes on the way and exits. In this case, a malfunction such as stop of these devices does not occur.

[0013]

According to the ultrasonic sensor of the present invention, a movement detection method using the Doppler effect and a presence detection method using detection of the presence or absence of reflection of an ultrasonic pulse are alternately switched, and the movement detection method is used. Before and after the movement of the object is detected, after detecting the presence of the intruding object by storing and comparing the reflection pattern from the object by the presence detection method, when a detection signal by the movement detection method is generated, The reflection pattern before the detection signal by the first movement detection method is obtained is compared with the current reflection pattern, and when the same comparison result as the already detected intruding object is obtained, the end of the detection output is determined. When the time is extended and the detection signal by the movement detection method is obtained within this extended time,
The detection output is not terminated until the reflection pattern before the detection signal from the first movement detection method is obtained and the current reflection pattern match. Even when an object enters and exits, the detection output continues to be generated until the original intruding object exits, and there is an effect that malfunction due to another intruding object can be eliminated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional example.

FIG. 3 is an operation explanatory diagram showing an operation of one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oscillator 2 Transmitting circuit 3 Ultrasonic transmitting device 4 Ultrasonic receiving device 5 Switching circuit for each transmission 6 Amplifying circuit 7 Mixer 8 Detecting circuit 9 Amplifying circuit 10 Timer circuit 11 Amplifying circuit 12 Detection judgment circuit 13 Transmission method determination Circuit 14 Detection circuit 15 Comparison circuit 16 Delay circuit 17 Storage circuit 18 Storage circuit 19 Comparison circuit 20 Judgment circuit

Claims (1)

(57) [Claims] 1. A transmitter for transmitting an ultrasonic wave into a monitoring space driven by a signal output from an oscillator, and a receiver for receiving a reflected wave from an object existing in the monitoring space. A first detection method for detecting the movement of an intruding object by detecting a frequency shift component generated in a received signal by the Doppler effect when the object moves, and transmitting an ultrasonic pulse from a transmitter. Means for alternately switching the second detection method for detecting the presence of an object in the monitored space by receiving a reflected wave from the object with the receiver at predetermined time intervals, and detecting the first detection method A first storage circuit that stores in time series a detection signal of the second detection method before a signal is first obtained, and a second storage method of the second detection method after the detection signal of the first detection method is obtained The detection signal of the first detection method is
When the comparison result of the second storage circuit that stores in time series each time it is obtained , the first comparison circuit that compares the storage contents of the first and second storage circuits, and the comparison result of the first comparison circuit do not match An ultrasonic sensor including a detection determination circuit that determines that an intruding object is present in the first detection circuit after the presence of the intruding object is detected by the first comparison circuit. A second comparison circuit for comparing the stored contents of the first and second storage circuits again, and the second comparison circuit
If a comparison result indicating that the storage contents of the first and second storage circuits do not match is obtained, a delay circuit for extending the end of the detection signal by a predetermined time, and again the first circuit within the extended time An ultrasonic sensor, comprising: a determination circuit that does not terminate the detection signal until the storage contents of the first and second storage circuits match when a detection signal of the above detection method is obtained.