Automobile collision prevention radar with own action failure detection function

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Industrial application field]

The present invention relates to an automobile collision prevention radar with a self-operation failure detection function. Currently, there is an automobile collision prevention radar that uses laser light, but this has the drawback of being vulnerable to fog and rain in principle.

【0002】

Therefore, the development of an automobile collision prevention radar using radio waves in a high frequency band such as millimeter waves is progressing, and is about to be realized in the near future. However, there is a demand for a type of automobile collision prevention radar under development that can detect its own malfunction.

【0003】

[Conventional technology]

FIG. 6 shows a block configuration diagram of a conventional automobile collision prevention radar and explains the block configuration diagram.

【0004】

The automobile collision prevention radar shown in FIG. 6 includes an oscillator 1, an amplifier 2, a multiplier 3, a hybrid circuit 4, an integrated transmission / reception antenna 5,5', and a mixer 6. ..

【0005】

The oscillator 1 outputs a signal S2 having a frequency corresponding to the set signal S1. However, the setting signal S1 is a triangular wave having a predetermined frequency (for example, 750 Hz), and it is assumed that the frequency of the signal S2 output from the oscillator 1 changes by changing the level of the triangular wave. Further, the signal S2 becomes an FM wave, and has a frequency of, for example, 30 GHz.

【0006】

The signal S2 is amplified by the amplifier 2, and this amplified signal S3 is input to the multiplier 3. The multiplier 3 multiplies the frequency of the input signal S3 and outputs it. For example, if the multiplier 3 is multiplied by 2, the signal S4 at 60 GHz is output from the multiplier 3.

【0007】

This signal S4 is branched by the hybrid circuit 4, and one signal S5 is output from the antenna 5 as a radio wave M1 in front of the own vehicle equipped with this radar. This output radio wave M1 is reflected by another vehicle traveling in front of the vehicle, which is not shown, and is returned as a reflected wave M2.

【0008】

The reflected wave M2 is received by the antenna 5', and the received signal S6 and the other signal S5' output from the hybrid circuit 4 are mixed by the mixer 6 and output as the signal S7.

【0009】

Since this signal S7 is a mixed signal of the Doppler frequency component due to the reflected wave M2 and the frequency component output from the multiplier 3, the frequency component of the signal S7 is detected and processed by a microcomputer or the like (not shown) to obtain the vehicle and the own vehicle. It is possible to detect the relative speed and relative distance to another vehicle, and if it is displayed, the driver can be notified, and in the case of danger, the driver can be notified by issuing an alarm.

【0010】

[Problems to be Solved by the Invention]

By the way, in the above-mentioned automobile collision prevention radar, when the radome (not shown) for covering and protecting the antennas 5, 5'is covered with muddy water or freezes, the radio waves output from the antenna 5 are the radio waves. Since radio waves that are reflected by muddy water or ice and are not attenuated at all through the antenna 5'are input to the mixer 6, the power of the output signal S7 of the mixer 6 becomes abnormally large, and the relative speed between the own vehicle and another vehicle, And the relative distance cannot be detected properly.

【0011】

That is, there is a problem that the radar itself malfunctions and the driver is notified of incorrect data, which is rather dangerous. The present invention has been made in view of such a point, and by making it possible to detect a malfunction of the radar itself, it is possible to notify the driver of the malfunction of the radar. Is intended to provide.

【0012】

[Means for solving problems]

The automobile collision prevention radar with a self-operation failure detection function according to the first principle of the present invention transmits a high-frequency signal output from a radar oscillator mounted on the own vehicle via a signal branching means to another vehicle or an obstacle in front of the antenna. After the reflected wave is received by the antenna, it is mixed with one of the high-frequency signals branched by the signal branching means by the mixer, and the frequency component of this mixed signal is detected and processed by the arithmetic processing means. In an automobile collision prevention radar that detects the relative distance and relative distance information between the own vehicle and other vehicles or obstacles and uses it for collision prevention, multiple electrodes fixed to the radome surface covering the antenna and conductivity to the radome surface. It is configured to be provided with a continuity detecting means for detecting that a predetermined number of electrodes have become conductive due to adhesion of a substance and outputting this detection signal.

【0013】

The second principle is that when the above-mentioned antenna is a transmission / reception shared antenna whose transmission / reception surface is covered with a radome, the power of the signal mixed by the above-mentioned mixer is detected, and the detected power value deviates from a predetermined value. It is configured to be provided with a power detecting means for outputting a signal notifying the malfunction of the antenna when the power value is large.

【0014】

It is preferable to provide a wiper for wiping the surface of the radome covering the transmission / reception shared antenna, and to operate the wiper when a signal notifying the malfunction of the antenna is output from the power detection means described above. A water injection means for injecting water onto the surface of the radome covering the transmission / reception shared antenna is provided so that water is injected from the water injection means when a signal notifying the malfunction of the antenna is output from the power detection means. It is preferable to configure it.

【0015】

The third principle includes a bias voltage detecting means that detects the bias voltage applied to the mixer and outputs a signal notifying the malfunction of the self-radar when the detected bias voltage deviates from a predetermined value. It is composed of.

【0016】

[Action]

According to the first principle of the present invention described above, it is possible to detect that a predetermined number of electrodes have become conductive due to the adhesion of the conductive substance to the surface of the radome. Therefore, for example, muddy water adheres to the surface of the radome. Or, it is possible to detect that the surface has frozen.

【0017】

Therefore, it is possible to detect that muddy water adheres to the surface of the radome or the surface freezes, which adversely affects the transmitted / received radio waves of the antenna, resulting in malfunction of the self-radar.

【0018】

According to the second principle, for example, when muddy water adheres to the surface of the radome covering the transmission / reception shared antenna or the surface freezes, the transmitted radio wave is reflected by the muddy water or ice, and a radio wave that is not attenuated at all is supplied to the mixer. , The output signal power of the mixer becomes high power and the radar malfunctions, but since the signal that notifies the malfunction of the antenna can be obtained by detecting the high power, it is detected that the malfunction of the self-radar has occurred. can do.

【0019】

In addition, since the wiper can be operated by the signal notifying the malfunction of the antenna and the muddy water or ice on the surface of the radome covering the transmission / reception shared antenna can be wiped off, the cause of the malfunction of the antenna, that is, the malfunction of the radar can be eliminated. it can.

【0020】

Furthermore, since water can be injected from the water injection means by a signal notifying the malfunction of the antenna to remove muddy water or ice on the surface of the radome, the cause of the malfunction of the radar can be eliminated.

【0021】

For example, as described above, if muddy water adheres to the surface of the radome or the surface freezes, which adversely affects the transmitted and received radio waves of the antenna, the radar will malfunction. For example, it is possible to detect that the bias voltage applied to the mixer deviates from the voltage value during normal operation, so that it is possible to know the malfunction of the self-radar.

【0022】

[Example]

Hereinafter, examples of the present invention will be described with reference to the drawings. FIG. 1 is a block configuration diagram of an automobile collision prevention radar with a self-operation failure detection function according to the first embodiment of the present invention. In this figure, the parts corresponding to the parts of the conventional example shown in FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted.

【0023】

The radar of the first embodiment shown in FIG. 1 uses a V-shaped mills cross antenna with good directivity as shown by a broken line, and one of the V-shaped antennas is the transmitting antenna 11 and the other is the transmitting antenna 11. It is a receiving antenna 12.

【0024】

The transmitting and receiving antennas 11 and 12 are covered by a radome 13. The feature element of the first embodiment is configured by independently attaching a plurality of electrodes 14 to the entire surface of the radome 13, connecting the conducting wires 15 to each of the electrodes 14, and connecting each of the conducting wires 15 to the continuity detection circuit 16. There is. However, the figure shows only one lead wire 15.

【0025】

The continuity detection circuit 16 detects the current or voltage when a predetermined number of electrodes 14 become conductive due to the muddy water 17 adhering to the surface of the radome 13 or the surface freezing. The conduction state is detected by the above, and the detection signal S8 is output.

【0026】

Originally, in such antennas 11 and 12, when muddy water 17 adheres or freezes over a wide area on the surface of the radome 13, the radio waves transmitted and received by antennas 11 and 12 are reflected by the muddy water 17 or ice and are appropriate. It becomes impossible to send and receive radio waves, and the role that the radar should play cannot be fulfilled.

【0027】

In this case, the radar malfunctions, but as described as a problem in the conventional example, it is rather dangerous if the driver cannot recognize the malfunction of the radar. In this embodiment, it is possible to detect a malfunction of the radar due to adhesion or freezing of muddy water 17 by detecting that a predetermined number of electrodes 14 are in a conductive state as described above.

【0028】

However, in a state where two electrodes 14 are conductive, the area of the adhered portion or the frozen portion of the muddy water 17 may not affect the transmission and reception of radio waves, so how many electrodes 14 are conductive. It is determined by experimental values whether the case affects transmission and reception, and when the obtained number of electrodes 14 becomes conductive, the conduction detection circuit 16 detects the conductive state and notifies the radar of malfunction. It is configured to output signal S8.

【0029】

In addition, when a conduction state that does not affect the transmission and reception of radio waves, for example, a continuity state between the two electrodes 14, an alarm signal indicating that muddy water has adhered or freezing has occurred is output from the continuity detection circuit 16. It may be done.

【0030】

As described above, if an alarm is issued to notify the malfunction of the radar caused by the malfunction of the antennas 11 and 12, the driver can be notified of the malfunction of the radar itself. Therefore, unlike the conventional case, it is not dangerous to inform the driver of erroneous information due to the malfunction of the radar itself.

【0031】

Next, a second embodiment will be described with reference to FIG. In FIG. 2, the parts corresponding to the parts of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and the description thereof will be omitted. The radar shown in FIG. 2 uses a parabolic antenna 21 having a primary radiator 20 as an antenna, and the opening of the antenna 21 is covered with a radome 22. Further, the antenna 21 is connected to the hybrid circuit 4 and the mixer 6 via the circulator 23.

【0032】

By the way, when the surface of the radome 22 is exposed to muddy water 26 or the surface freezes, the radio waves output from the antenna 21 are reflected by the muddy water 26 or ice as described in the problem of the conventional example. Since radio waves that are not attenuated at all are input to the mixer 6, the power of the output signal S7 of the mixer 6 becomes abnormally large, causing the radar to malfunction, and if the driver cannot recognize this radar malfunction, it becomes dangerous. There is.

【0033】

The feature of this second embodiment is that a power detection circuit 25 for detecting the power of the output signal S7 of the mixer 6 is provided, and when the detected power value deviates from a predetermined value, muddy water adheres to the radome 22 or freezes. It is possible to detect that the radar is malfunctioning.

【0034】

When the power detection circuit 25 detects that the output signal S7 power of the mixer 6 deviates from a predetermined value, the detection signal S9 is output. If the detection signal S9 issues an alarm notifying the malfunction of the radar due to the malfunction of the antenna 21, the driver can be notified of the malfunction of the radar itself.

【0035】

Further, as shown in FIG. 3, a wiper 31 that moves left and right on the surface of the radome 22 is provided, and as described above, when muddy water or ice adheres to the surface of the radome 22 is detected by the power detection circuit 25. If the wiper 31 is activated by the detection signal S9 and configured to remove muddy water or ice, the cause of the malfunction of the radar can be eliminated.

【0036】

In addition, as shown in FIG. 4, a water injection device 32 that injects water 33 onto the surface of the radome 22 is provided, and the water injection device 32 is activated by the detection signal S9 output from the power detection circuit 25 to inject water 33. However, if it is configured to remove muddy water or ice adhering to the surface of the radome 22, the cause of the malfunction of the radar can be eliminated.

【0037】

Next, a third embodiment will be described with reference to FIG. In FIG. 5, the parts corresponding to the respective parts of the conventional example shown in FIG. 6 are designated by the same reference numerals, and the description thereof will be omitted. The feature of the third embodiment shown in FIG. 5 is the DC bias voltage V applied to the mixer 6._BThe present invention includes a bias voltage detection circuit 35 that detects whether or not is a predetermined voltage value and outputs a detection signal S10 when the voltage deviates from the predetermined voltage value.

【0038】

As is well known, the mixer 6 is composed of a combination of diodes, and a part of the transmission power is used as the local power generation. When a local power is applied to the diode used in the mixer 6, its bias voltage value changes to a predetermined value.

【0039】

If the transmission system fails and the local power generation does not come, or if the diode breaks down, the bias voltage value will deviate from the predetermined value. Therefore, as described above, the bias voltage V in the bias voltage detection circuit 35._BIf the detection signal S10 is output when the voltage deviates from the predetermined voltage value by detecting, the detection signal S10 issues an alarm notifying the malfunction of the radar to the driver and operates the radar itself. It can inform you of defects.

【0040】

[Effect of the invention]

As described above, according to the automobile collision prevention radar with the self-operation failure detection function of the present invention, it is possible to detect the malfunction of the radar itself due to muddy water adhering to the antenna, freezing, and the like. Since it is effective, it has the effect of notifying the driver of the malfunction of the radar itself.

[Simple explanation of drawings]

[Figure 1]

It is explanatory drawing of the automobile collision prevention radar with the self-operation failure detection function by 1st Embodiment of this invention.

[Figure 2]

It is explanatory drawing of the automobile collision prevention radar with the self-operation failure detection function by 2nd Embodiment of this invention.

[Fig. 3]

It is explanatory drawing of the schematic mechanism which combined the wiper with the radome shown in FIG.

[Fig. 4]

It is explanatory drawing of the schematic mechanism which combined the water injection device with the radome shown in FIG.

[Fig. 5]

It is explanatory drawing of the automobile collision prevention radar with the self-operation failure detection function by the 3rd Embodiment of this invention.

[Fig. 6]

It is a block block diagram of the conventional automobile collision prevention radar.

[Explanation of symbols]

11,12 antenna 13 Radome 14 electrodes 16 Continuity detection means 17 Conductive substances (muddy water, ice, etc.) 21 Transmission / reception shared antenna 25 Power detection means 31 wiper 32 Water injection means 35 Bias voltage detection means