JP3244797B2 - Automobile collision prevention radar with self-failure detection function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile collision prevention radar having a self-failure detection function. At present, there is an automobile collision prevention radar that uses laser light, but has a drawback that it is basically weak against fog and rain.

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

[0003]

2. Description of the Related Art FIG. 3 is a block diagram showing the configuration of a conventional automobile collision prevention radar.

The automobile collision preventing radar shown in FIG. 3 comprises an oscillator 1, a transmitting amplifier 2, a multiplier 3, a hybrid circuit 4, an antenna 5, a receiving amplifier 6, and a mixer 7.
And a signal processing unit 8.

The oscillator 1 outputs a signal S2 having a frequency corresponding to the setting signal S1. However, the setting signal S1
Is a predetermined frequency wave, and by changing the level of this wave, the frequency of the signal S2 output from the oscillator 1 changes. Also, the signal S2 becomes an FM wave,
For example, the frequency is 30 GHz.

The signal S2 is amplified by the amplifier 2, and the amplified signal S3 is input to the multiplier 3. The multiplier 3 multiplies the frequency of the input signal S3 and outputs the same.
Assuming that the signal has been multiplied, the signal 3
Is output.

The signal S4 is branched by the hybrid circuit 4, and one signal S5 is output from the antenna 5 as a radio wave M1 to the front of the vehicle equipped with the radar.
The output radio wave M1 is reflected by, for example, another vehicle traveling ahead (not shown) and returns as a reflected wave M2.

The reflected wave M 2 is received by the antenna 5 and amplified by the amplifier 6. The amplified signal S7 and the other signal S5 'output from the hybrid circuit 4 are mixed by the mixer 7 and output as a signal S8.

Since the signal S8 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 is detected and processed by the signal processing unit 8 composed of a microcomputer or the like. By doing
The relative speed and the relative distance between the own vehicle and the other vehicle are detected and output as a signal S9.

If the signal S9 is displayed on a display unit (not shown) using the signal S9, the driver can be informed, and in the event of danger, the driver can be alerted and notified.

[0011]

The above-mentioned automobile collision prevention radar has a problem that when the radar itself breaks down, the driver is informed of incorrect data, which is rather dangerous.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and enables a radar to detect a self-failure so that the driver can be informed of the failure. It is intended to provide radar.

[0013]

With reference to FIG. 1, the construction of a vehicle collision prevention radar with a self-failure detection function according to the first principle of the present invention will be described.

The first principle is that, after a high-frequency signal output from an oscillator 1 of a radar mounted on the own vehicle is amplified by a transmission-side amplifier 2, the frequency is multiplied by a multiplier 3 to a predetermined multiple, and the signal is split. Is output to another vehicle or an obstacle ahead of the vehicle, and the reflected wave is amplified by the receiving-side amplifier 6 and then mixed with one of the high-frequency signals branched by the signal branching means by the mixer 7. In an automobile collision prevention radar which detects a relative distance between the own vehicle and the other vehicle or an obstacle and detects relative distance information by detecting the frequency component of the signal by the arithmetic processing means to help prevent collision, the oscillator 1 transmits the signal. The gate current Ig of each of the transistors constituting the side amplifier 2, the multiplier 3, the reception side amplifier 6, and the mixer 7 is detected. It is obtained by forming the gate current detection diagnostic circuit 11 for outputting a signal indicating the failure of the da provided.

Further, the above-described gate current detection and diagnosis circuit 1
1, a gate current Ig having an appropriate width flowing through transistors constituting the oscillator 1, the transmission-side amplifier 2, the multiplier 3, the reception-side amplifier 6, and the mixer 7 is set. If it is determined that the current value is not the set gate current Ig value, a signal may be output to notify the driver of the failure of the own radar.

Referring to FIG. 2, the configuration of an automobile collision prevention radar with a self-failure detection function according to the second principle of the present invention will be described. The second principle is that, after a high-frequency signal output from an oscillator 1 of a radar mounted on the own vehicle is amplified by a transmission-side amplifier 2, the frequency is multiplied to a predetermined multiple by a multiplier 3 and the signal is passed through a signal branching unit. The signal is output to another vehicle or an obstacle ahead, and the reflected wave is amplified by the receiving amplifier 6 and then mixed with one of the high-frequency signals branched by the signal branching unit by the mixer 7, and the frequency components of the mixed signal are mixed. Is detected by the arithmetic processing means, thereby detecting the relative distance and the relative distance information between the own vehicle and the other vehicle or the obstacle, and controlling the operation of the brake and the accelerator of the own vehicle according to the detection result. In an automobile collision prevention radar that performs operation control, the gate current Ig of each of the transistors constituting the oscillator 1, the transmitting amplifier 2, the multiplier 3, the receiving amplifier 6, and the mixer 7 is detected. If it is determined that the gate short, with releasing the aforementioned operation control, which is constituted by providing a gate current detection diagnostic circuit 12 for outputting an alarm to inform the driver vehicle that has been released.

The gate current detection and diagnosis circuit 12 includes an oscillator 1, a transmitting amplifier 2, a multiplier 3, a receiving amplifier 6,
When a gate current Ig value having an appropriate width flowing through the transistor constituting the mixer 7 is set, and it is determined that the detected value of each gate current Ig of the transistor is not the set gate current Ig value, the operation control described above is performed. Release it,
It may be configured to output an alarm that informs the driving vehicle of the release.

Further, the gate current detection and diagnosis circuit 12
As described above, when it is determined from the gate current Ig that the gate is short-circuited, or when it is determined that the detected value of each gate current Ig of the transistor is not the set gate current Ig value, the brake is applied or the accelerator is released. It may be configured to output a signal for performing such control and to output an alarm indicating that the control has been performed.

[0019]

According to the first principle of the present invention, the self-radar oscillator 1,
Transmitting-side amplifier 2, multiplier 3, receiving-side amplifier 6, mixer 7
The gate current Ig of the transistor constituting the transistor is detected and it is determined that the gate is short-circuited from the gate current Ig, or the detected value of the gate current Ig of the transistor is determined not to be the set gate current Ig value In addition, a signal that informs the driver of the failure of the self-radar is output, so that if the radar itself fails, the driver is informed of incorrect data as before, and there is no danger that it is rather dangerous .

According to the second principle, the gate current detection diagnostic circuit 12 detects each gate current Ig of the transistors constituting the oscillator 1, the transmitting amplifier 2, the multiplier 3, the receiving amplifier 6, and the mixer 7, When it is determined from the gate current Ig that the gate is short-circuited, or when the detected value of each gate current Ig of the transistor is determined not to be the set gate current Ig value, the above-described operation control is canceled, An alarm is output to notify the driving vehicle of the release.

Therefore, the vehicle does not perform erroneous driving control due to the radar failure, and the driver can recognize the radar failure. Further, when the gate current detection and diagnosis circuit 12 detects a failure of the self-radar, a signal for controlling whether to apply a brake or loosen the accelerator is output from the gate current detection and diagnosis circuit 12, and the control is performed. When an alarm is output to notify that the vehicle is running, the own vehicle is automatically decelerated or stopped, and the driver can confirm this automatic control by the alarm, so that the rear-end collision prevention effect is further improved.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a vehicle collision prevention radar with a self-failure detection function according to a first embodiment of the present invention. In this figure, parts corresponding to the respective parts of the conventional example shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

First, the history of the construction of this embodiment will be described. Most of the failures of the automobile collision prevention radar described in the conventional example, that is, the malfunctions in the high-frequency circuit such as the millimeter wave constituting the radar, are caused by the failure of the semiconductor device used.

As a semiconductor device, a device such as an FET is used. If the device is deteriorated and fails, its current consumption changes. In this case, the gate current always changes.

Therefore, the gate current of each FET constituting the radar is monitored, and if the gate current is significantly different from the initial set value, it is recognized as a circuit operation failure, and a warning is issued to the driver using the recognition result. Alternatively, the driving control by the radar may be canceled, and the cancellation may be notified to the driver by an alarm.

Another advantage is that monitoring is easy because only a small amount of the gate current of each FET flows. Next, an automobile collision prevention radar with a self-failure detection function configured based on such a concept will be described with reference to FIG.

The radar according to the first embodiment shown in FIG. 1 is different from the conventional radar shown in FIG. 2 in that an oscillator 1, a transmission amplifier 2, a multiplier 3, a reception amplifier 6, and a mixer 7 are provided.
(These 1, 2, 3, 6, and 7 are referred to as devices.) Gate current detection for detecting a gate current Ig and determining whether the detected gate current Ig is an appropriate operating current. That is, the diagnostic circuit 11 is provided.

When the gate current detection / diagnosis circuit 11 determines that an appropriate gate current Ig is not flowing to any of the devices 1, 2, 3, 6, 7, an alarm signal ALM1 for notifying the driver of the fact is provided. Is output.

The criterion for the gate current detection / diagnosis circuit 11 to determine whether an appropriate gate current Ig is flowing to each of the devices 1, 2, 3, 6, 7 is based on the gate current Ig.
It is assumed that the gate is short-circuited or that the detected gate current Ig does not fall within the current value width predetermined for failure diagnosis in the circuit 11.

According to the radar having such a configuration, it is possible to detect a failure of the own radar and notify the driver of the failure. And that it is no longer dangerous.

Next, a second embodiment will be described with reference to FIG. However, in FIG. 2, portions corresponding to the respective portions of the first embodiment shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The difference between the second embodiment and the first embodiment is that the gate current detection and diagnosis circuit 12
When it is determined that an appropriate gate current Ig does not flow through the gates 6 and 7, by outputting the control release signal S10,
The operation of the radar is released by cutting off the signal S9 output from the signal processing unit 8, and an alarm signal ALM2 for notifying the driver of the release is output.

However, the operation control is control of the brake and the accelerator. In addition, the gate current detection diagnostic circuit 12
However, when it is determined that the appropriate gate current Ig is not flowing, the brake may be applied or a signal for releasing the accelerator may be output.

According to the radar of the second embodiment, similarly to the first embodiment, it is possible to inform the driver that the radar has failed, and to cancel the driving control or apply the brake, Since the accelerator can be loosened, the effect can be exhibited by preventing collision.

[0034]

As described above, according to the automobile collision prevention radar with the self-failure detection function of the present invention, there is an effect that the failure of the radar itself can be detected. Has the effect that the driver can be informed.

Further, there is an effect that it is possible to prevent a rear-end collision by applying a brake or loosening an accelerator according to a failure detection result.

[Brief description of the drawings]

FIG. 1 is a block diagram of an automobile collision prevention radar with a self-failure detection function according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a vehicle collision prevention radar with a self-failure detection function according to a second embodiment of the present invention.

FIG. 3 is a block diagram of a conventional automobile collision prevention radar.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Oscillator 2 Transmitting amplifier 3 Multiplier 4 Signal branching means 5 Antenna 6 Receiving amplifier 7 Mixer 8 Signal processing part 11, 12 Gate current detection diagnostic circuit

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Suzuki 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Yoshiaki Nakano 1015 Ueodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited ( 56) References JP-A-50-140290 (JP, A) JP-A-64-42904 (JP, A) JP-A-56-1009011 (JP, A) JP-A-4-189629 (JP, A) JP-A-2-246838 (JP, A) JP-A-1-297579 (JP, A) JP-A-60-132041 (JP, U) JP-A-1-104829 (JP, U) (58) Fields investigated (Int) .Cl. ⁷ , DB name) G01S 7/40 B60T 7/12 G01S 13/93 G08B 13/00 G08G 1/16

Claims (2)

(57) [Claims] 1. A high-frequency signal output from an oscillator having a field-effect transistor of a radar mounted on an own vehicle is output to another vehicle or an obstacle ahead through a signal branching unit, and a reflected wave of the high-frequency signal is output to the signal. One of the high-frequency signals branched by the branching means is mixed with a mixer having a field-effect transistor, and the frequency component of the mixed signal is detected and processed by the processing means. Outputs a signal indicating the relative relationship with other vehicles and obstacles.
According to, in an automobile collision prevention radar that controls the operation of the own vehicle , detecting the gate current of each of the field-effect transistors,
An automobile with a self-failure detection function , comprising: a gate current detection diagnosis circuit for interrupting a signal from the arithmetic processing means when it is determined from the detection result that the gate is short-circuited. Anti-collision radar. 2. A gate current value having an appropriate width flowing through the field effect transistor is set in the gate current detection and diagnosis circuit, and the detected gate current value of the field effect transistor is set to the set gate current value. 2. The vehicle collision prevention radar with a self-failure detection function according to claim 1, wherein a signal from said arithmetic processing means is cut off when it is determined that said signal is not a fault.