JP2001099912A - Sensor with function for self-diagnosing normal operation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio wave sensor having highly reliable detection performance by self-diagnosing the normal operation of sensor function in a system from a sensor transmission part through its reception part using a detection output of the sensor. SOLUTION: The normal operation of the sensor is judged by detecting the detection output, from the reception part 7, generated by a near distance reflected wave in an antenna radome 8, in the sensor comprising the transmission part 1 for transmitting a radio wave, a transmission antenna 2 for emitting a transmission wave into the air, a reception antenna 6 for inputting the reflected wave of the transmitted radio wave reflected by a detecting object 4, the reception part 7 for detecting the reflected wave, the antenna radome 8 for covering the transmission antenna 2 and the reception antenna 6, a diagnostic part 10 for detecting the normal operation of the sensor using the detection output from the reception part 7, and a judging part 11 for judging the normal operation of the sensor using the detection output from the reception part 7 and a detection result from the diagnostic part 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a normal operation determination of a radio wave type sensor.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 17, a radio wave sensor radiates a transmission wave 3 from a transmission unit 1 into the air by a transmission antenna 2 and reflects a reflection wave of the transmitted radio wave from a detection target 4. The distance of the object is detected from the detection output obtained by receiving the reception antenna 6 and detecting the reception wave 5 by the reception unit 7.

[0003]

However, according to the conventional method, even if a failure occurs in the transmitting unit or the receiving unit after the sensor is installed and the sensor cannot be normally detected,
Since the detection output is obtained as it is, there is a problem that the validity of the detection result cannot be determined.

The present invention has been made in view of the above points, and has as its object to use a detection output of a sensor to perform normal operation of a sensor function of a system through a sensor transmission unit and a reception unit. An object of the present invention is to provide a radio wave sensor having highly reliable detection performance by performing self-diagnosis.

[0005]

According to a first aspect of the present invention, there is provided a transmitting unit for transmitting a radio wave, a transmitting antenna for radiating a transmitted wave into the air, and a transmitting wave for reflecting a reflected wave from an object to be detected. A receiving antenna for inputting, a receiving unit for detecting a reflected wave, the transmitting antenna, an antenna radome covering the receiving antenna, a diagnostic unit for detecting a normal operation of a sensor using a detection output of the receiving unit, A detection unit that determines a normal operation of the sensor using a detection output from the unit and a detection result from the diagnosis unit, and detects a detection output from the reception unit caused by a short-range reflected wave at the antenna radome. Thus, the normal operation of the sensor is determined.

According to a second aspect of the present invention, there is provided a transmitting unit for transmitting a radio wave, a transmitting antenna for radiating a transmitted wave into the air, a receiving antenna for inputting a reflected wave of the transmitted radio wave from a detection target, A receiving unit that detects a reflected wave; a high-frequency circuit unit to which the transmitting antenna, the receiving antenna, the transmitting unit, and the receiving unit are connected; and a diagnosis that detects a normal operation of the sensor using a detection output of the receiving unit. And a determination unit that determines a normal operation of the sensor using a detection output from the reception unit and a detection result from the diagnosis unit, wherein a part of the transmission wave due to circuit mismatch in the high-frequency circuit unit By detecting the detection output from the receiving unit that occurs when input to the receiving unit as a short-range reflected wave,
The normal operation of the sensor is determined.

[0007] The invention described in claim 3 is based on claim 1 or
In the invention according to claim 2, for a sensor whose sensor radar system is an FMCW system, the diagnostic unit includes a low-pass filter and a detection circuit, and uses the low-pass filter to perform the diagnosis. A normal operation of the sensor is determined by extracting a low-frequency component generated by a short-range reflected wave from a detection output of the receiving unit and detecting the low-frequency component by the detection circuit.

[0008] The invention described in claim 4 is based on claim 1 or
3. The sensor according to claim 2, wherein the sensor has a pulse Doppler radar system, wherein the diagnostic unit includes a switch and a detection circuit, and switches the switch to detect a detection output from the receiving unit. A normal operation of the sensor is determined by extracting a direct-current component generated by a short-range reflected wave from and detecting the detected direct-current component by the detection circuit.

[0009]

FIG. 1 shows a first embodiment of a sensor with a normal operation self-diagnosis function according to the present invention.
4 to FIG. 4 for the second embodiment.
9 to 13 for the third embodiment, and FIG.
This embodiment will be described in detail with reference to FIGS.

[First Embodiment] FIG. 1 is a schematic configuration diagram of a sensor with a normal operation self-diagnosis function according to a first embodiment. In FIG. 1, reference numeral 1 denotes a transmitting unit that transmits a radio wave, and 2 denotes a transmitting antenna that radiates a transmitting wave 3 from the transmitting unit 1 into the air. 4 is a detection object, 5 is a detection object 4
Is a received wave obtained by reflecting the transmitted wave 3. 6
Is a receiving antenna for inputting the received wave 4, and 7 is a receiving unit for detecting the received wave 5 from the receiving antenna 6. Reference numeral 8 denotes an antenna radome that covers the transmission antenna 2 and the reception antenna 6, and reference numeral 9 denotes a short-range reflected wave in which the transmission wave 3 radiated from the transmission antenna 2 is reflected by the antenna radome 8. Further, reference numeral 10 denotes a diagnostic unit for detecting a normal operation of the sensor by branching a part of the detection output of the receiving unit 7 and 11 using a detection output from the receiving unit 7 and a detection result from the diagnostic unit 10. A normal operation of the sensor.

As shown in FIG. 1, the circuits of the transmitter 1 and the receiver 7 of the sensor are operating normally, and the transmission antenna 2
When the transmission / reception system of the sensor is operating normally, for example, when the reception antenna 6 is securely connected, as shown in FIG. Output 1 caused by short-range reflected waves
There are three. For this reason, if this detection output can be detected by the diagnosis unit 10, it can be determined that the sensor is operating normally, and if this output cannot be detected, it can be determined that the sensor is operating abnormally.

Further, if this is used, as shown in FIG.
If the detection output 14 is generated at a certain distance, and if the detection output generated by the short-range reflected wave of the antenna radome 8 is detected, the above-described determination unit 10 in FIG. If the detection output 13 as shown in FIG. 3 caused by the short-range reflected wave of the antenna radome 8 is not detected, as shown in FIG. It is assumed that the detection result is obtained by erroneous detection, and it can be determined that the detection result is erroneous.

[Second Embodiment] FIG. 5 is a schematic configuration diagram of a sensor with a normal operation self-diagnosis function according to a second embodiment. In FIG. 5, 1 to 7, and 10, 11 are:
This is the same as that described with reference to FIG. Reference numeral 15 denotes a high-frequency circuit unit to which the transmitting unit 1, the transmitting antenna 2, the receiving antenna 6, and the receiving unit 7 are connected.

FIG. 6 is a schematic diagram showing one embodiment of the high-frequency circuit section 15. As shown in FIG. 6, a transmitting unit 1, a transmitting antenna 2, a transmitting wave 3, a receiving wave 5, a receiving antenna 6, and a receiving unit 7 are the same as those described with reference to FIG.
A signal line 16 connects the transmitting unit 1 and the transmitting antenna 2 and the receiving unit 7 and the receiving antenna 6. Reference numeral 17 denotes an antenna terminal, which connects the transmitting unit 1 and the transmitting antenna 2.

As shown in FIG. 6, in the high-frequency circuit section 15, a signal line connecting the transmitting section 1 and the transmitting antenna 2 includes:
When the receiving section 7 and the signal line connecting the receiving antenna 6 are arranged close to each other, and furthermore, a circuit impedance mismatch occurs at the antenna terminal 17, a part of the transmission wave becomes a short-range reflected wave at the antenna terminal 17. 18 and leaks in the signal line 16 and is detected by the receiving unit together with the received wave. As described above, by using the reflected wave generated in the high-frequency circuit unit 15 as the short-range reflected wave, the presence or absence of the short-range reflected wave is detected in the same manner as in FIGS. A determination can be made.

FIG. 7 is a schematic configuration diagram of a general FMCW sensor. In FIG. 17, 1 to 6 are the same as those described in FIG. 1 described above. Reference numeral 19 denotes a directional coupler, which branches a part of the transmission wave from the transmission unit and supplies it to the mixer. Reference numeral 20 denotes a mixer for multiplying a part of the transmission wave and the reception wave. Reference numeral 21 denotes a distance calculation unit,
The distance to the detection target is obtained from the detection output obtained from the output of 0.

FIG. 8 is a diagram showing the principle of an FMCW sensor. 8, (1) shows a temporal frequency change of the transmission wave 3 and the reception wave 5, and (2) shows a temporal frequency change of the detection output of the mixer 20. As shown in FIG. 8A, the transmission wave 3 is obtained by frequency-modulating a carrier with a triangular wave. The reception wave 5 receives a time delay 22 according to the distance between the detection target and the sensor, and further receives a Doppler shift 23 generated according to the relative speed between the detection target 4 and the sensor. When the transmission wave and the reception wave are multiplied by the mixer 20, the difference frequency component is obtained as a detection output.
As shown in (2), in the section where the modulation frequency given by the triangular wave increases and decreases, the detection target 4
And a frequency component corresponding to the distance and relative speed of the sensor.

Therefore, in the distance calculation unit 21 of FIG.
By detecting the frequency 24 of the detection output in the section where the modulation frequency increases and the frequency 25 of the detection output in the section where the modulation frequency decreases, the distance R and the relative speed V between the detection target 4 and the sensor are calculated as follows. It can be obtained by the formula.

R = {(fu + fd) × C × Tm}
/ (8 × ΔF) V = {(fd−fu) × C} / (4 × F0) where fu: frequency of the detection output in the section where the modulation frequency increases fd: the frequency of the detection output in the section where the modulation frequency decreases Frequency C: Propagation speed of radio wave Tm: Repetition period of triangular wave ΔF: Maximum deviation width of modulation frequency F0: Center frequency of transmission wave [Third Embodiment] FIG. 9 shows a normal operation according to a third embodiment. It is a schematic structure figure about a diagnosis part of an FMCW system sensor as a sensor with a self-diagnosis function. 9, 10, 11, 20, and 21 are the same as those described in FIGS. 1 and 7 described above. Reference numeral 26 denotes a low-pass filter, which selects only signals existing in a certain low-frequency region from the detection output obtained from the mixer 20. A detection circuit 27 detects the presence or absence of the low-frequency signal selected by the low-pass filter 26.

As shown in FIG. 9, the transmission / reception system of the sensor is such that the circuits of the transmission unit 1 and the reception unit 7 of the sensor are operating normally and the transmission antenna 2 and the reception antenna 6 are securely connected. Is operating normally, as shown in FIG. 10, a low-frequency signal 29 generated by a short-range reflection wave in the antenna radome 8 and the high-frequency circuit unit 15 exists in the low-frequency region 28 in the detection output. I do. Therefore, if this detection output can be detected by the detection circuit 27, it can be determined that the sensor is operating normally, and if this output cannot be detected, it can be determined that the sensor is operating abnormally.
If this is used, as shown in FIG. 11, when a detection output 30 is generated at a certain frequency, if a low-frequency signal generated by a short-range reflection wave of the antenna radome 8 or the high-frequency circuit unit 15 is detected, The detection unit 11 of FIG. 9 can determine that the detection result is correct. Conversely, as shown in FIG. 12, if the low-frequency signal generated by the short-range reflection wave of the antenna radome or the high-frequency circuit unit is not detected, the detection result is obtained. Is assumed to have been obtained by erroneously detecting an interference wave or the like, and can be determined to be an erroneous detection result.

FIG. 13 is a schematic structural view of a general pulse Doppler type sensor. In FIG. 13, 2 to 6,
20 is the same as that described in FIGS. 1 and 7 described above. 31 is a modulator, 32 is a pulse generator, and 33 is an oscillator. The modulator 31 performs amplitude modulation on a carrier wave from the oscillator 33 with a pulse signal from the pulse generator 32.

FIG. 14 is a diagram showing the principle of a pulse Doppler sensor. As shown in FIG. 14A, the modulator 31 uses the pulse signal 34 from the pulse generator 32.
FIG. 14B shows a transmission wave when the amplitude modulation is performed on the carrier wave from the oscillator 32 in FIG. A received wave 5 obtained from a receiving antenna 6 after being reflected by a detection target 4
Receives a time delay corresponding to the distance between the detection target 4 and the sensor as shown in FIG. 14C, and further receives a Doppler shift generated according to the relative speed between the detection target 4 and the sensor.
When the received wave 6 and a local oscillation signal 35 obtained by branching a part of the oscillator 33 shown in FIG. 14 (d) are multiplied by the mixer 20, the difference frequency component is obtained as shown in FIG. 14 (e). A certain Doppler signal 36 is determined. Therefore, the distance R between the detection target 4 and the sensor can be obtained by the following equation by detecting the time delay in the distance calculation unit 21 in FIG.

R = (C × T) / 2 where C: propagation speed of radio wave T: time delay between transmitted wave and received wave [Fourth Embodiment] FIG. 15 shows a third embodiment of the present invention. It is a schematic structure figure about a diagnosis part of a pulse Doppler system sensor as a sensor with an operation self-diagnosis function. FIG.
5, 10, 11, 20, 21, and 32 are the same as those described with reference to FIGS. 1 and 13 described above. Three
A switch 7 switches the Doppler signal output from the mixer to the detection circuit for a certain short period and the remaining time to the distance calculation unit, using a rising edge of the pulse signal from the pulse generator as a trigger. A detection circuit 27 detects the presence or absence of the detection output selected by the switch.

FIG. 16 is a diagram showing the principle of a diagnostic method during normal operation. As shown in FIG. 16A, the transmission wave 3 obtained when the amplitude modulation is performed on the carrier wave from the oscillator in the modulator using the pulse signal 34 from the pulse generator 32 as shown in FIG. 16B. Become. When the circuit of the sensor's transmitting unit 1 and the receiving unit 7 is operating normally, and the transmitting and receiving system of the sensor is operating normally, for example, the transmitting antenna 2 and the receiving antenna 6 are securely connected. As shown in FIG. 16C, a short-range reflected wave is generated in the antenna radome 8 and the high-frequency circuit unit 15. Since this receives a time delay according to the distance between the detection target and the sensor, the transmission wave 3 and the local oscillation signal have the same frequency having a certain phase difference according to the distance between the detection target 4 and the sensor. Signal.

Therefore, as shown in FIG. 16 (g), in the detection output obtained from the output of the mixer 20, the phase difference corresponding to the phase difference falls within a certain short time region 38 (t) after the pulse signal rises. There is a DC component 39 having a different level. Therefore, if this detection output can be detected by the detection circuit 27, it can be determined that the sensor is operating normally, and if this output cannot be detected, it can be determined that the sensor is operating abnormally. Also, if this is used, if the Doppler signal is generated at a certain distance, and if a DC component with a small time delay caused by a short-range reflected wave of the antenna radome 8 or the high-frequency circuit unit 15 is detected, FIG.
5 can be determined as a correct detection result, and conversely, if a DC component with a small time delay caused by a short-range reflection wave of the antenna radome 8 or the high-frequency circuit unit 15 is not detected, the detection result is an interference wave or the like. Is erroneously detected and can be determined to be an erroneous detection result.

In the present embodiment, the case where the sensor system is the pulse Doppler system has been described.
Even when frequency modulation is performed using a trapezoidal wave instead of a triangular wave in a CW sensor, an output similar to that of the pulse Doppler method can be obtained in a portion where the frequency of the transmitted wave is constant. Can be applied. As described above, the diagnostic method is not particularly limited to the sensor method as long as the same output as that of the pulse Doppler sensor can be obtained.

[0027]

As described above, according to the first aspect of the present invention, by detecting the detection output from the receiving unit caused by the short-range reflected wave at the antenna radome, the normal operation of the sensor transmitting / receiving unit is detected. The self-diagnosis is performed, and the radio wave sensor having highly reliable detection performance can be provided.

According to the second aspect of the present invention, a detection output from the receiving unit, which is generated when a part of the transmission wave is input to the receiving unit as a short-range reflected wave due to circuit mismatch in the high-frequency circuit unit, is detected. This has the effect of performing a self-diagnosis of the normal operation of the sensor transmitting / receiving section and providing a radio wave sensor having highly reliable detection performance.

According to the invention described in claim 3, according to claim 1
Or, in addition to the effect of the invention according to claim 2, furthermore, regarding the sensor of the radar system of the FMCW system, the configuration of the diagnosis unit includes a low-pass filter and a determination circuit, and the low-pass filter is provided. The self-diagnosis of the normal operation of the sensor transmitting and receiving unit is performed by extracting the low-frequency component generated by the short-range reflected wave from the output signal from the receiving unit and detecting the low-frequency component by the detection circuit. There is an effect that a radio wave sensor having high performance can be provided.

According to the fourth aspect of the present invention, the first aspect is provided.
Or, in addition to the effect of the invention described in claim 2, the radar system of the sensor is a pulse Doppler system,
The configuration of the diagnostic unit includes a switch and a detection circuit, and switches the switch to extract a DC component with a small time delay caused by a short-range reflected wave from the detection output from the reception unit and detect the DC component with the detection circuit. By
The self-diagnosis of the normal operation of the sensor transmitting and receiving unit is performed, and an effect is provided that a radio wave sensor having highly reliable detection performance can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a first embodiment of a sensor with a normal operation self-diagnosis function according to the present invention.

FIG. 2 shows the sensor with a normal operation self-diagnosis function.
FIG. 9 is a diagram illustrating a detection output of a receiving unit when a short-range reflected wave exists.

FIG. 3 shows the sensor with a normal operation self-diagnosis function,
FIG. 9 is a diagram illustrating a detection output of the receiving unit in a normal operation.

FIG. 4 shows the sensor with a normal operation self-diagnosis function,
FIG. 9 is a diagram illustrating a detection output of the receiving unit at the time of an abnormal operation.

FIG. 5 is a schematic configuration diagram of a sensor with a normal operation self-diagnosis function according to a second embodiment of the present invention.

FIG. 6 shows the sensor with a normal operation self-diagnosis function,
It is a schematic structure figure showing one example of a high frequency circuit part.

FIG. 7 is a schematic configuration diagram of a general FMCW sensor.

FIG. 8 is a diagram showing the principle of an FMCW sensor.

FIG. 9 is a schematic configuration diagram illustrating an example of a diagnosis unit in a sensor with a normal operation self-diagnosis function according to a third embodiment of the sensor with a normal operation self-diagnosis function according to the present invention.

FIG. 10 is a diagram showing a detection output of a mixer when a short-range reflected wave exists in the sensor with a normal operation self-diagnosis function.

FIG. 11 is a diagram showing a detection output of a mixer during normal operation in the sensor with a normal operation self-diagnosis function.

FIG. 12 is a diagram showing a detection output of a mixer during abnormal operation in the sensor with a normal operation self-diagnosis function.

FIG. 13 is a schematic configuration diagram of a general pulse Doppler sensor.

FIG. 14 shows various signal waveforms showing the principle of a pulse Doppler sensor.

FIG. 15 is a schematic configuration diagram illustrating an example of a diagnosis unit in a sensor with a normal operation self-diagnosis function according to a fourth embodiment of the sensor with a normal operation self-diagnosis function according to the present invention.

FIG. 16 is a diagram showing the principle of a diagnosis method during normal operation in the sensor with a normal operation self-diagnosis function.

FIG. 17 is a schematic configuration diagram of a conventional radio wave sensor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transmission unit 2 transmission antenna 2 transmission antenna 3 transmission wave 4 detection object 5 reception wave 6 reception antenna 7 reception unit 8 antenna radome 10 diagnosis unit 11 determination unit 15 high frequency circuit unit 20 mixer 21 distance calculation unit 31 modulator 32 pulse generation Vessel 33 oscillator

[Procedure amendment]

[Submission date] August 9, 2000 (200.8.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007] The invention described in claim 3 is based on claim 1 or
In the invention according to claim 2, with respect to a sensor whose sensor radar system is an FMCW system, the diagnosis unit includes a low-pass filter and a detection circuit, and performs the reception using the low-pass filter. A normal operation of the sensor is determined by extracting a low-frequency component generated by a short-range reflected wave from the detection output of the unit and detecting the low-frequency component by the detection circuit.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Explanation of sign

[Correction method] Change

[Correction contents]

[Description of Signs] 1 Transmitting unit 2 Transmitting antenna 3 Transmitting wave 4 Detected object 5 Received wave 6 Receiving antenna 7 Receiving unit 8 Antenna radome 10 Diagnosis unit 11 Judging unit 15 High frequency circuit unit 20 Mixer 21 Distance calculation unit 31 Modulator 32 Pulse generator 33 Oscillator

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Hirata 1048 Kadoma Kadoma, Osaka Prefecture F-term in Matsushita Electric Works, Ltd. (reference) 5J046 AA02 AA05 AB00 RA00 5J070 AB01 AB19 AC02 AD02 AK40 BA01 BG03

Claims (4)

[Claims] A transmitting unit for transmitting a radio wave, a transmitting antenna for radiating the transmitted wave into the air, a receiving antenna for inputting a reflected wave of the transmitted radio wave from a detection target, and a receiving unit for detecting the reflected wave An antenna radome that covers the transmitting antenna and the receiving antenna, a diagnostic unit that detects a normal operation of a sensor using a detection output of the receiving unit, a detection output from the receiving unit, and a detection result from the diagnostic unit. A determination unit that determines a normal operation of the sensor by using a detection unit. The normal operation of the sensor is determined by detecting a detection output from the reception unit caused by a short-range reflected wave at the antenna radome. A sensor with a normal operation self-diagnosis function. 2. A transmitting unit for transmitting a radio wave, a transmitting antenna for radiating the transmitting wave into the air, a receiving antenna for inputting a reflected wave of the transmitted radio wave from a detection target, and a receiving unit for detecting the reflected wave A high-frequency circuit unit to which the transmitting antenna, the receiving antenna, the transmitting unit, and the receiving unit are connected, a diagnostic unit that detects a normal operation of a sensor using a detection output of the receiving unit, And a determining unit that determines a normal operation of the sensor using the detection output of the diagnostic unit and a detection result of the diagnostic unit. A sensor with a normal operation self-diagnosis function, wherein a normal operation of the sensor is determined by detecting a detection output from the reception unit which is input to the reception unit. 3. The sensor radar system is FMCW (Freququ
For a sensor of the ency modulated continuous wave) type, the diagnosis unit includes a low-pass filter and a detection circuit, and uses the low-pass filter to perform short-range reflection from the detection output of the reception unit. The normal operation of the sensor is determined by extracting a low frequency component generated by the wave and detecting the low frequency component by the detection circuit.
The sensor with a normal operation self-diagnosis function according to claim 2. 4. The sensor according to claim 1, wherein the diagnostic unit comprises a switch and a detection circuit, and switches the switch so that a short-range reflection is output from the detection output from the receiving unit. 3. The sensor with a normal operation self-diagnosis function according to claim 1, wherein a normal operation of the sensor is determined by extracting a DC component generated by the wave and detecting the DC component by the detection circuit.