JP2584892B2 - Method and apparatus for detecting state of object detector - Google Patents

Description

Description: TECHNICAL FIELD [0001] The present invention relates to a state detection method for an object detector.

[Prior art and its problems] Generally, this type of object detector detects an object to be detected by moving the object to or away from a detection unit, and detects the presence of the object from the detection unit. A corresponding signal is output, and an output signal is output when the detection signal reaches a predetermined value.

This type of object detector has a first stable operation state, for example, a stable operation state in which the object to be detected is sufficiently far away and the detector is off, and a second stable operation state, for example, in which the object to be detected is sufficient for the detector. Approaching and the detector has a stable operating state in which it remains on. Here, the stable operation means (A) the detection signal is sufficiently small when there is no detected object, and (B) the detection signal is sufficiently large when the detected object is present. It is ideal that an unstable operation signal is output from the object detector when the object detector is operating in other states.

Some detectors themselves determine whether the object detector is in a stable operation state and output a state signal. That is, as shown in FIG. 6, the detection signal from the detection unit 1 is compared with a preset reference level L3 in the first comparator 1, that is, a set value for judging the detection signal of the object to be detected. The presence / absence of an object, approach or separation are determined, and the detection signal is compared with a second comparator 2 having an upper limit level L1 higher than a reference level L3 of the first comparator 1 to determine whether the detection signal is appropriate. Have been determined.

FIG. 7 shows the relationship between the detection signal, the object detection signal S, the upper limit level L1, and the first reference level L3 in FIG. In this figure, a reference level for obtaining an object detection output in order to determine a detection signal S and a detection signal S by the detection unit.
It has two reference setting values L3 and an upper limit level L1 for detecting a stable operation in addition to the reference level L3. That is, an upper limit level L1 for unstable operation is provided at a position higher than the reference level L3 by a predetermined value, an unstable operation area Zd is provided between the upper limit level L1 and the reference level L3, and a stable operation is performed in an area exceeding the upper limit level L1. An object determination output is output based on a comparison output between the reference level L3 and the object detection signal S as a region Zf. In this method, it is confirmed that the object detector is in a normal state when the object detection signal S exceeds the reference level L3 and enters the unstable operation region Zd, and further exceeds the upper limit level L1 and enters the stable operation region Zf. Also, as shown in FIG. 8, when the detection signal object detection signal S exceeds the reference level L3, but enters the unstable operation area Zd and falls through the reference level L3 without exceeding the upper limit level L1, it is not possible. A stable operation signal is output, and the detector is determined to be in an unstable operation state.

In this method, since the boundary of the unstable operation area Zd for judging the unstable operation state matches the judgment set value of the signal for obtaining the object detection output, that is, the reference level L3, the object detection signal S
Is smaller than the third set value, the object detection signal S and the third
No matter how small the difference from the set value is, the determination cannot be made, and an unstable operation signal cannot be output even if the operation is performed in an unstable state.

In contrast to the above method, as shown in FIG. 9, the lower limit level L2, which is a reference set value smaller than the reference level L3, for setting the determination set value of the object detection signal S, that is, the reference level L3, inside the unstable operation area. A method is conceivable in which the lower limit level L2 is compared with the object detection signal S to determine whether the operation is unstable when the object detection output is inverted. According to this method, since the unstable operation regions Zd1 and Zd2 are present on both sides of the reference level L3 as compared with the above-described method, it is more excellent and the following two states can be determined. That is, when the object detection signal S rises from a sufficiently small state and exceeds the reference level L3, an object detection output is issued, and the object detection signal S decreases without reaching the upper limit level L1 and falls below the lower limit level L2. When the object detection signal S falls below the upper limit level L1 and falls below the reference level L3 from a state where the object detection signal S is sufficiently large, the object detection output is inverted, and does not fall below the lower limit level L2. , An unstable operation signal can be issued.

In this method, when the object detection signal S passes the reference level L3, it is used for the determination of the unstable operation. When entering the operation area Zd1 and returning to the stable operation area on the upper level L1 side before reaching the reference level L3,
Alternatively, the object detection signal S is output from the stable operation area Zd2 on the lower level L2 side from the stable operation area on the lower level L2 side before returning to the stable operation area on the lower level L2 side before reaching the reference level L3. There is a problem that an unstable operation signal is not output because the signal does not pass through the reference level L3.

[Object of the Invention] The present invention relates to an original stable operation in which an object detection signal exceeds a reference set value in an unstable operation region from one or the other stable operation region and does not enter an opposite stable operation region. Not only when returning to the stable operation region, but also when entering the unstable operation region from one of the stable operation regions and returning to the original stable operation region without reaching the reference set value. An object of the present invention is to realize a method and a device for detecting a state of an object detector that outputs a stable operation signal.

[Summary of the Invention] According to the present invention, an unstable operation area is provided for an object detection signal output from a detection unit in accordance with the presence of an object to be detected, and a set value for object detection output determination exists in that area. The object detection signal enters the unstable operation area from one of the stable operation areas, but returns to the original stable operation area without entering the stable operation area on the opposite side. Is issued.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

That is, in FIG. 1, 1 is a first set value, for example, a first set value L1 which is an upper limit of the unstable operation region Zd in FIG.
Is a second comparator having a second set value L2 which is the lower limit of the unstable operation region Zd, and 3 is a first comparator having the first set value L1 and the second set value L2 in the unstable operation region Zd. A third comparator 5, which has a third set value set in the middle of the set value L2, is a detector, and a first comparator, a second comparator, and a second comparator are provided at the output terminal of the detector 5. The input terminals of three comparators 3 are connected. Output terminals of the first comparator 1 and the second comparator 2 are connected to an input terminal of the state determination circuit 6. On the other hand, the output terminal of the third comparator 3 is connected to the input terminal of the output circuit 7. An output operation unit 12 is formed by the third comparator 3 and the output circuit 7. Output terminals of the state determination circuit 6 and the output circuit 7 are connected to the display unit 8, respectively. Reference numeral T9 indicates an output terminal of the state determination circuit 6, and reference numeral T10 indicates an output terminal of the output circuit 7.

Next, the operation in the above configuration will be described with reference to FIG. First, the presence / absence of the detected object 11 is detected by the detection unit 5, and an object detection output is output in response thereto. This signal is connected to the first, second and third comparators 1, 2, 3
Compare the two settings. Note that these comparators may have hysteresis as needed.

The first set value L1 is compared with the object detection signal S by the first comparator 1, and this output is used as a first determination signal J1,
This is input to the state determination circuit 6.

Further, the second set value L2 smaller than the first set value L1 is compared with the object detection signal S by a second comparator, and its output is used as a second judgment signal J2, which is input to the state judgment circuit 6. I do.

On the other hand, the third comparator 3 compares the third set value L3, which is smaller than the first set value L1 and is larger than the first set value L2, with the object detection signal S, and outputs the output through the output circuit 7. Output to the output terminal T10. As a result, the presence or absence of the detected object 11 is output from the output terminal T10.

The state determination circuit 6 determines that the first determination signal J1 is equal to the first set value.
When L1 is set as a reference, the operation is inverted when the operation enters the first stable operation region Z1 from the first stable operation region Z1 or into the unstable operation region Zd1. Similarly, when the second determination signal J2 enters the unstable operation region Zd from the second stable operation region Z2 based on the second set value L2, or when the unstable operation region
It is inverted when it goes out of Zd to the second operation stable area Z2.

Then, the first determination signal J1 enters the unstable operation region Zd1 from the first stable operation region Z1 on the basis of the first set value, whereby the second determination signal J1 is inverted from the time t9 when the first determination signal J1 is inverted. Without returning to the first stable operation area Z2, and thereby returning to the first stable operation area Z1.
When the second judgment signal J2 is not inverted before the time t10 when the second judgment signal J2 is inverted, and when the second judgment signal J2 is equal to the second set value.
From the second inversion operation area Z2 based on L2, the operation enters the unstable operation area Zd, and from the time t5 when the second determination signal J2 is inverted, the second operation signal Z2 does not enter the first stable operation area Z1 and the second inversion operation area Zd. Returning to the stable operation area Z2, the second determination signal
When the first determination signal J1 is not inverted before the time t6 when J2 is inverted, the state determination signal J0 is inverted to output that the object detector is in an unstable operation.

To summarize the operation of this algorithm, the comparison signal between the reference level L3 and the object detection signal S is not used unlike the conventional example, and the judgment signal enters the unstable operation area from the stable operation area and then enters When returning, set the status judgment signal,
When the vehicle passes through the opposite side, the state determination signal is reset.

FIG. 3 shows a flowchart of the operation of the state determination circuit 6.

In the above-described embodiment, when the object detection signal S is not smooth as shown in FIG. 4, for example, when the detected object 11 is moving while shaking, the object detection signal S becomes the first signal. When passing through the set value L1, the second set value L2, or the third set value L3, a pulse-like signal may be generated as the state determination signal. This can be solved by providing the first comparator 1, the second comparator 2, and the third comparator 3 with an appropriate hysteresis.

Further, as described above, if there are only J1 and J2, a case where the object detection signal S shown in FIG. 4 fluctuates near the third set value and a pulse-like signal is generated in the object detection output is not expected. Although it cannot be determined that the operation state is stable, the third operation for obtaining an object detection output
Such a state can also be detected as an unstable operation state by adding a comparison signal between the set value of the above and the object detection signal S to the state determination.

That is, in the operation of FIG. 4 shown as a conventional example, the object detection signal is obtained from when the comparison signal of the third set value L3 for obtaining the object detection output and the object detection signal S is inverted to when it is inverted again. S does not exceed the first set value L1,
When the value does not fall below the second set value L2, this state can also be detected as an unstable operation state.

[Effects of the Invention] As described above, the present invention outputs an object detection signal (S) according to the presence of an object to be detected, and compares a first set value with the object detection signal (S). 1 is output, a second set value smaller than the first set value is compared with the object detection signal (S), and a second judgment signal is output.
A third set value smaller than the first set value and larger than the second set value is compared with the object detection signal (S) to output a third determination signal, and based on the third determination signal, Outputting an object detection output, when the second determination signal is not inverted between the time when the first determination signal is inverted and when it is inverted again, and when the second determination signal is inverted. Since the unstable operation signal is output when the first determination signal is not inverted before the inversion is performed again, the object detection signal (S) is not detected from one of the stable operation regions. Not only when exceeding the reference set value in the stable operation area and returning to the original stable operation area without entering the stable operation area on the opposite side, but also from one or the other stable operation area to the unstable operation area And the third setting Even for the case to return to the original stable operating region without reaching a value, there is an effect that it is possible to output an unstable operation signal.

Further, a comparison signal between the third set value (L3) for obtaining the object detection output and the object detection signal (S) is added to the state determination, so that the object detection signal (S) becomes close to the third set value (L3). Even in the case where a pulse signal is generated in the object detection output due to swinging, there is an effect that an unstable operation state can be detected.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing an embodiment of a state detection method of an object detector according to the present invention, FIG. 2 is a waveform diagram showing an operation state of FIG. 1, and FIG. 3 is a state determination circuit in FIG. FIG. 4 is a waveform diagram of a special operation state in FIG. 1, FIG. 5 is a waveform diagram for explaining an unstable operation signal, and FIG. 6 is a block circuit diagram of a conventional object detector. 7 and 8 are operation waveform diagrams in FIG. 6, and FIG. 9 is an operation waveform diagram showing another conventional example. In the drawings, the same reference numerals indicate the same or corresponding parts. DESCRIPTION OF SYMBOLS 1 ... 1st comparator 2 ... 2nd comparator 3 ... 3rd comparator 5 ... Detection part 6 ... State determination circuit 7 ... Output circuit 8 ... Display part 11 ... Detected Object 12 Output operation unit T9 Output terminal T10 Output terminal L1 First set value L2 Second set value L3 Third set value Z1 First stable operation area Z2: second stable operation area Zd (Zd1, Zd2): unstable operation area S: object detection signal J1: first determination signal J2: second determination signal J0: state determination signal

Claims (3)

(57) [Claims] An object detection signal (S) is output according to the presence of an object to be detected, and a first determination value is output by comparing a first set value with the object detection signal (S). , The first
A second set value smaller than the set value is compared with the object detection signal (S), a second determination signal is output, and a third set value smaller than the first set value and larger than the second set value is output. A set value is compared with the object detection signal (S), a third determination signal is output, an object detection output is output based on the third determination signal, and again when the first determination signal is inverted. When the second determination signal is not inverted before the inversion, and when the first determination signal is not inverted between the time when the second determination signal is inverted and the time when the second determination signal is inverted again. A method of detecting the state of an object detector that issues an unstable operation signal. 2. A detection unit for outputting an object detection signal (S) according to the presence of an object to be detected, and comparing a first set value with the object detection signal (S) and outputting a first determination signal. First
A second comparator that compares a second set value smaller than the first set value with the object detection signal (S) and outputs a second determination signal; and a second comparator that outputs a second determination signal. A third setting value which is smaller than the value and which is larger than the second setting value and which is compared with the object detection signal (S) and outputs a third determination signal;
And an output circuit that outputs an object detection output based on the third determination signal, and the second determination signal is inverted between when the first determination signal is inverted and when it is inverted again. A state determination circuit that outputs an unstable operation signal when the first determination signal is not inverted when the second determination signal is not inverted and when the second determination signal is inverted again. A state detection device for an object detector, characterized in that: 3. A detection unit for outputting an object detection signal (S) according to the presence of an object to be detected, and comparing the first set value with the object detection signal (S) to generate a first determination signal. A first comparator for outputting, a second comparator for comparing a second set value smaller than the first set value with the object detection signal (S), and outputting a second determination signal; A third comparator that compares a third set value smaller than the first set value and larger than the second set value with the object detection signal (S) and outputs a third determination signal; An output circuit for outputting an object detection output based on the determination signal of the above, and the second determination when the second determination signal is not inverted between the time when the first determination signal is inverted and the time when the second determination signal is inverted again Unless the first determination signal is inverted between the time when the signal is inverted and the time when the signal is inverted again. And a state determination circuit that outputs an unstable operation signal when neither of the first and second determination signals is inverted between the time when the third determination signal is inverted and the time when the third determination signal is inverted again. A state detecting device for an object detector.