JPH0737176A - Object detecting device - Google Patents

Abstract

PURPOSE:To provide an object detecting device whereby not only a travelling object but also a still object are surely detected, the workability of an equipment for it is satisfactory and also an installation cost is reduced. CONSTITUTION:A P-P voltage detecting circuit 5 detecting a P-P voltage based on a AC signal obtained from an IF signal from a microwave Doppler sensor 1, a frequency discriminating circuit 4 detecting a frequency from the P-P voltage and a DC shift voltage detecting circuit 6 are provided and also a detection discriminating circuit 7 discriminating presence or absence of the existance of the object inside a detection area by judgement whether or not at least one detection value of the circuits is within the set range of the circuit or judgement based on history information of an output from the P-P voltage detecting circuit till then when the DC shift voltage is zero is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object detecting apparatus for detecting a person, a moving object such as a dolly or a cart, or an object placed in front of a door in order to open and close an automatic door.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for detecting a human body or another moving object used for an automatic door or the like, there is an apparatus using infrared rays or microwaves. In this microwave device, as shown in FIG. 10, the detection is performed by a signal (hereinafter referred to as an IF signal) obtained by extracting only a difference component between a transmitted wave and a received wave, and the signal processing is performed by the IF signal. The peak-to-peak voltage (hereinafter, referred to as P-P voltage) of 1 is discriminated depending on whether or not it is higher than a predetermined value. But, for example, when a person stands still near the door,
The PP voltage becomes "0", and in this case, the detection signal is not output. Therefore, there is a danger that the door may be closed and a person may be caught.

For this reason, conventionally, in order to prevent the above-mentioned situation, a safety ray provided separately from the door switch detects a human body under the door, and the door switch has a static sensor dedicated to the under door. The safety under the door has been ensured by providing such as.

[0004]

By the way, in the prior art, in order to ensure the safety under the door, it is necessary to provide a sensor and equipment for transmitting and receiving a safety ray, and the construction for that is required. It was required separately. Therefore, there are problems that the workability is poor and that the construction cost is increased.

In view of these problems, the present invention can reliably detect both a moving object and a stationary object, and the installation workability of the equipment therefor is good, and the installation cost is reduced. It is an object of the present invention to provide an object detection device capable of achieving the above.

[0006]

In order to achieve the object of the present invention, the moving object detecting apparatus of the present invention will be described with reference to FIG. 1 corresponding to an embodiment. A microwave Doppler sensor 1 that receives the reflected wave, mixes the received signal and outputs an IF signal, and a positive peak and a negative peak based on an AC signal obtained from the IF signal. Between P
-P-P voltage detection circuit 5 for detecting the P-voltage and its P-
The circuit is provided with a frequency discriminating circuit 4 for detecting the frequency by the P voltage and a DC shift voltage detecting circuit 6 for detecting the DC shift voltage based on the DC signal obtained from the IF signal. Of at least one of the detected values is within the set range in the circuit, or if the DC shift voltage is zero, the history information of the output from the PP voltage detection circuit 5 is used. It is characterized by comprising a detection discrimination circuit 7 for discriminating the presence or absence of an object in the detection area based on the judgment based on the above.

[0007]

FIG. 3 is a diagram showing the installation situation of the embodiment of the present invention, and FIG. 4 is a waveform diagram of the transmitted microwave TX and the received floor reflected wave RX ₁ and mixing of these waveforms. the waveforms obtained Te is a diagram showing a mixer output IF ₁ was DC shift. In addition, FIG. 5 shows the transmitted microwave TX.
FIG. 5 is a waveform diagram of the received human body reflected wave RX ₂ and a diagram showing the mixer output IF ₂ of these waveforms as in FIG. 4.

With reference to these drawings, the following acts
State. First, if there is no object in the detection area,
As shown in 4, the floor reflected wave RX ₁Is microwave TX
As a signal with the same frequency, different phase, and lower level
Be received. Mixer output IF in this case₁P-P voltage
Is almost zero, and a constant low level DC deviation voltage
V_EBecomes

On the other hand, when there is a moving object in the detection area, the moving object reflected wave RX ₂ has a frequency higher than that of the microwave TX due to the Doppler effect, as shown in FIG.
It is received as a signal whose level gradually increases. Further, the mixer output IF ₂ shows a change as shown in FIG. 5, although the rate of increase or decrease differs depending on the speed of the moving object.

For example, when a person enters the detection area of an automatic door, moves forward toward the door, moves through the door and moves outside the door, a PP voltage detection circuit, a frequency discrimination circuit, a DC shift voltage detection. For each output from the circuit, the changes are described in the order of approach, under the door, and outside the door. First, the P-P voltage is low level, high level, low level, and the frequency is high level, low level, high level. The DC shift voltage changes to a low level, a high level, and a low level. It should be noted that the low level and the high level referred to here are values that are smaller than the high level range, and a range having a relatively large value among the ranges divided by the set values set in each circuit is defined as the high level. The range with is defined as the low level.

The frequency f (IF) of the mixer output
And the P-P voltage V ₀ are expressed by equations (1) and (2), respectively.

[0012]

[Equation 1]

[0013]

## EQU00002 ## First, according to the equation (1), it can be seen that in this case, when cos .theta. In other words, the frequency f (IF) becomes low as the moving speed of the person becomes low near the door. Also,
According to the equation (2), since V _m and cos θ are constant, it can be seen that they change depending on the distance between the person and the door. That is, as the value approaches s, the value of s decreases, so the PP voltage V ₀ suddenly increases.

When a person stands still under the door, the DC shift voltage becomes zero, but it occurs due to the history of changes in the PP voltage V ₀ , that is, when the person moves. Its existence can be recognized by the history information of the change of the PP voltage V ₀ .

[0015]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment of the present invention, an object is detected,
An automatic door system for opening and closing the door will be described as an example.

FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention. The microwave Doppler sensor 1 receives an M / W wave oscillator 1a that oscillates a microwave, a transmission antenna 1b for transmitting the microwave, and a reflected wave of the microwave reflected from the floor surface or a human body. A reception antenna 1c and a mixer 1d for mixing the received microwaves and outputting a mixer signal are provided.

Further, an AC amplifier circuit 2 for AC-amplifying the mixer output and a DC amplifier circuit 3 for DC-amplifying the mixer output are provided, and a frequency discrimination detection circuit 4 to which signals from the AC amplifier circuit 2 are respectively input, a PP voltage. Detection circuit 5, also
A DC shift detection circuit 6 to which a signal from the DC amplification circuit 3 is input is configured. In addition, these circuits 4, 5, 6
A condition discrimination circuit 7 that recognizes the object detection based on the detection result input from the device, and outputs a detection signal when detected, and a pulse width modulation circuit for making the pulse width sufficient for the response of the door engine. Alternatively, there is a timer 8 having a timing circuit to keep the door open for a sufficient time for a person to pass through.

When the detection signal is output, a driving unit (not shown) for driving the opening and closing of the automatic door is driven together with the timer 8. The object detecting apparatus of the embodiment of the present invention having the above configuration is provided and installed in the microwave unit 30 shown in FIG. The range of the detection area A can be arbitrarily set depending on the beam direction of the microwave oscillated from the microwave unit 30.

FIG. 2 is a circuit block diagram of an essential part of the embodiment of the present invention. The microprocessor 21 is used as a hardware configuration for recognizing and determining the detection of the object with respect to the detected values of the frequency, the P-P voltage, and the DC shift voltage described above, and compares the detected values and changes with time. The history information of the detected value is stored in the storage area in order to recognize that, and the discrimination as described later is performed based on these.

The microprocessor 21 is provided with four analog ports P ₁ ... P ₅ . The output from the capacitor C1 and the amplifier OP1, that is, a signal having a voltage waveform in the middle of 0 V and V _CC and having an amplified AC component of the IF signal is input to the analog port P ₁ . Further, the analog port P ₂ has a voltage waveform in the middle of 0 V and V _CC for the output from the amplifier OP2, that is, a signal having a frequency equal to or lower than a predetermined frequency selected by the low pass filter (LPF), and A signal obtained by amplifying the DC component of the IF signal is input. As will be described later, based on the signal input to the analog port P ₁ , a change in frequency and the P-P voltage value are detected, and based on the signal input to the analog port P ₂ , a DC shift voltage is detected. To be detected.

Further, at the analog port P ₃ , P− detected by adjusting the rotation angle of V _R1 to a predetermined value.
A signal that can set the boundary value of the range that determines the discrimination level for recognizing that the P voltage value has detected the object is input. Also, for the analog port P ₄ , the rotation angle of V _R2
Further, by adjusting the rotation angle of V _R3 to the analog port P ₅ , a signal capable of setting the boundary value of the range that similarly determines the discrimination level for the frequency and the DC deviation voltage is input. Has become.

Thus, in the microprocessor 21,
When any of the obtained frequency, P-P voltage value, and DC shift voltage is within the range in which detection is recognized, the relay 22 is turned "ON" to drive the drive unit of the automatic door.

Here, a method for obtaining each of the frequency, the PP voltage value, and the DC shift voltage and a method for discriminating them will be described with reference to specific examples. First, FIG. 8 is a diagram for explaining a method of obtaining the PP voltage value and the frequency by the signal input to the analog port P ₁ .

The voltage waveform shown in (a) of the same figure is (b) of the same figure.
It corresponds to the voltage data string for each timing of 10 ms shown in
It Further, FIG._R1Set by the rotation angle of
Level, that is, 'R_H‘R’_L’, 0’
Boundary value (V_th1L,V_th1H) Is a graph which asks. Well
No, P-P voltage value V₀Of the positive and negative peak values
Difference (V₀= 3.0V−1.9V = 1.1V)
It The frequency f is the positive zero-cross point and the negative zero-cross point.
Time, that is, half wavelength time (10ms × 6 = 60ms)
The time of 1 wavelength (60ms × 2 = 120ms) is calculated from
In this case, it is required to be about 8Hz
To be Furthermore, the P-P voltage value V previously obtained₀Is the same figure
According to (c), for example, 1 V or less is “0”, 1 V or more 2
Less than V is ‘R _L’R above 2V_HWas set as ’
Then, in this case ‘R_L’

FIG. 9 shows the analog port P₂Input to
Fig. 4 is a diagram for explaining the method of obtaining the DC shift voltage by
is there. The voltage waveform shown in FIG. 7A is shown in FIG.
It corresponds to a voltage data string for each timing of 10 ms. Well
In addition, FIG._R2Set by the rotation angle of
Level, ie, 'R_H‘R’_L’,‘ Constant ’boundary
Boundary value (V_th2L,V_th2H) Is a graph which asks. example
For example, if the voltage data string is 2.8V, the level is ‘R’. _H'When
To be judged.

Regarding the operation of the embodiment of the present invention having the above-described structure, an example in which a person moves toward a door and further passes through will be described below. FIG. 6A shows a state in which the detection apparatus of the embodiment of the present invention is installed and the position of a human being detected, and the positions are M ₁ , M ₂ , M ₃ ,
FIG. 6B shows the change in the waveform of the mixer output IF corresponding to the time-dependent change of M ₄ and M ₅ , and the frequency, the PP voltage, and the DC shift voltage appearing at each position. 6 (c) shows the change in the discrimination level of.

Here, " _RH " and "R" shown in FIG.
_L 'is the same as the level set by the above method. Therefore, the frequency, by detecting the P-P voltage and the DC shift voltage, respectively, one of these detection results 'R _H' or 'R _L'
In this case, the human body is discriminated from the one existing in the detection area, and the detection signal is output.

First, in M ₁ and M ₅ , the frequency is 0, the PP voltage is ≈0, and the DC shift voltage is a constant value. In this case, no detection signal is output. Further, M ₂ indicates a time when the human body is approaching, M ₃ indicates a time when the person comes under the door, and M ₄ indicates a time when the human body moves away. In this case, as for the frequency, the moving speed becomes smaller under the door, so the frequency becomes lower,
It changes from " _RH " to " _RL " and again to " _RH ", while for PP voltage and DC shift voltage, conversely, from " _RL " to " _RH " and again to " _RL ". And changes.

As described above, in the embodiment of the present invention, it is possible to normally detect the detected value of any one of the frequency, the PP voltage and the DC shift voltage. It should be noted that even when a person stands still under the door, the person is inevitable to make a slight movement, and thus is detected as described above. However, as shown in FIG. , A state in which the human body is not detected, for example, as in M ₁ of FIG. 6C, frequency = 0, PP voltage ≈
In some cases, a signal of 0, DC deviation = constant may be output. In this case, discrimination is performed based on history information indicating the change in PP voltage up to that point with time. That is, P-P
When the voltage changes in the order of "≈0", " _RL ", " _RH ", and "≈0", it is recognized as detected and a detection signal is output.

When a large luggage is placed under the door, the luggage may be caught by controlling the door to be kept open until the state of M ₄ shown in FIG. 6 appears. Does not occur.

[0031]

As described above, according to the object detecting apparatus of the present invention, the IF from the microwave Doppler sensor is detected.
A P-P voltage detection circuit for detecting a P-P voltage based on an AC signal obtained from the signal, a frequency discrimination circuit for detecting a frequency by the P-P voltage, and a DC signal obtained from the IF signal. And a DC shift voltage detection circuit for detecting a DC shift voltage, and determining whether or not at least one detection value of these circuits is within a set range in the circuit, or When the DC shift voltage is zero, a configuration including a detection discriminating circuit for discriminating the presence or absence of an object in the detection area based on the judgment based on the history information of the output from the P-P voltage detecting circuit up to that point Therefore, both moving objects and stationary objects can be reliably detected, and troubles such as being caught when a person stands still under a door as in the conventional case do not occur. Moreover, since it can be realized with one sensor, the workability of the equipment is good and the work cost can be reduced.

[Brief description of drawings]

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

FIG. 2 is a circuit block diagram of a main part of an embodiment of the present invention.

FIG. 3 is a diagram showing an installation situation of an embodiment of the present invention.

FIG. 4 is a diagram for explaining an output waveform of a floor surface reflection microwave received by the embodiment of the present invention.

FIG. 5 is a diagram for explaining an output waveform of a human body reflected microwave received by the embodiment of the present invention.

FIG. 6 is a diagram for explaining the operation of the embodiment of the present invention.

FIG. 7 is a diagram illustrating a case where the mobile terminal stands still under a door in the embodiment of the present invention.

FIG. 8 is a diagram illustrating a detection method applied in the embodiment of the present invention.

FIG. 9 is a diagram illustrating a detection method applied in the embodiment of the present invention.

FIG. 10 is a circuit block diagram of a main part of a conventional example.

[Explanation of symbols]

 1 ... Microwave oscillating unit 2 ... Microwave receiving unit 3 ... DC amplification circuit 4 ... Frequency discrimination circuit 5 ... PP voltage detection circuit 6 ... DC deviation detection circuit 7 ... Detection discrimination circuit

Claims (1)

[Claims] 1. A microwave Doppler sensor for oscillating a microwave in a detection area, receiving a reflected wave thereof, mixing the received signal and a transmitted signal and outputting an IF signal, and a microwave Doppler sensor obtained from the IF signal. A P-P voltage detection circuit that detects a P-P voltage between a positive peak and a negative peak based on an AC signal, a frequency discriminating circuit that detects a frequency by the P-P voltage, and the IF signal. And a DC shift voltage detection circuit for detecting the DC shift voltage based on a DC signal obtained from the circuit, and whether at least one detection value of the circuit is within a set range in the circuit. Whether or not, or when the DC shift voltage is zero, by the judgment based on the history information of the output from the PP voltage detection circuit until then,
An object detection device comprising a detection discrimination circuit for discriminating the presence or absence of an object in the detection area.