JP2005069923A - Surroundings monitoring device for vehicle, and abnormality detection method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surroundings monitoring device for a vehicle capable of accurately detecting abnormality of a device and capable of improving reliability of it. <P>SOLUTION: A surroundings monitoring device 11 for a vehicle comprises a transmitting means 3 for transmitting radio waves and a receiving means 4 for receiving the reflected radio waves that has been transmitted. It comprises an abnormality judging means 12a which judges whether there is abnormality or not by comparing reception levels of the reflected radio waves transmitted toward a ground surface when an engine is started with a preset normal reception level range. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a vehicle periphery monitoring device and an abnormality detection method for the vehicle periphery monitoring device, and more specifically, a vehicle periphery for monitoring an object existing around the vehicle, such as the front and rear sides of the vehicle. The present invention relates to a monitoring device and an abnormality detection method for detecting an abnormal operation of the vehicle periphery monitoring device.

In recent years, various types of vehicle distance control, pedestrian protection control, occupant protection control, etc. are detected by radar on objects in front or rear of the vehicle in order to prevent rear-end collisions or personal injury caused by automobiles. Development of a safety support system is underway.

FIG. 5 is a block diagram schematically showing a main part of a conventional radar mounted on a vehicle and monitoring an object existing in front of the vehicle. In the figure, reference numeral 1 denotes a radar, and the radar 1 includes a processing unit 2, a transmission unit 3, and a reception unit 4.

The transmission means 3 generates electromagnetic pulses and transmits them from an antenna (not shown).
The receiving unit 4 is configured to receive the reflected pulse of the electromagnetic pulse transmitted from the transmitting unit 3 via the antenna and detect the reception level of the reflected pulse.

The processing unit 2 acquires data related to the reception level of the reflected pulse detected by the receiving unit 4 and performs arithmetic processing, and includes an object discriminating unit 2a. If the object discriminating means 2a determines whether or not the reception level of the reflected pulse acquired from the receiving means 4 is equal to or higher than a predetermined threshold, that is, if it is determined that the object is present around the vehicle,
An object detection signal is output to various control devices. Thus, by mounting the radar 1 on the vehicle, it is possible to monitor objects around the vehicle.

FIG. 6 is a graph showing a received waveform of a reflected pulse received by the conventional radar 1.
a) shows a waveform with a reception level equal to or higher than the threshold value, and (b) shows a waveform with a reception level less than the threshold value. The horizontal axis indicates time, and the vertical axis indicates the reception level.

In the conventional radar 1 as described above, as shown in FIG. 6A, when the reception level of the reflected pulse is equal to or higher than a predetermined threshold, it is determined that an object exists around the vehicle. As shown in FIG. 6B, when the reception level of the reflected pulse is less than a predetermined threshold, it is determined that there is no object around the vehicle.

However, when an abnormality occurs in the radar 1 and an accurate reception level cannot be detected, even if an object exists around the vehicle (that is, in a normal state, the reception level equal to or higher than the threshold value is present). It is also assumed that the reception level is detected below the threshold value although it should be detected.

However, since the conventional radar 1 cannot detect an abnormality due to a failure of the radar 1 or the like, if the reception level is less than the threshold, the reception level is low because there is no object around the vehicle, or the radar 1 is abnormal. Therefore, there is a problem that it is impossible to determine whether the reception level is low. Moreover, since it was not possible to determine whether or not the detected reception level is an accurate reception level, there is a problem that there is a risk that the reception level is used without being accurately detected.

In Patent Document 1 below, an output of an A / D conversion unit that samples a beat wave output from an FM-CW radar and converts it into a digital signal is greater than or equal to a predetermined maximum value or a predetermined minimum value. A technique for determining an abnormality when the following outputs are included is disclosed.

However, the technique disclosed in Patent Document 1 is intended to determine an abnormality when the distance and relative speed include an error due to noise superimposed on the reflected wave, and cannot detect an abnormality due to a radar failure or the like. The above problem could not be solved.
Japanese Patent Laid-Open No. 9-80151

Means for solving the problems and their effects

The present invention has been made in view of the above problems, and can detect an abnormality of the apparatus accurately, improve the reliability of the apparatus, and promptly notify the occupant that there is an abnormality. It is an object of the present invention to provide a vehicle periphery monitoring device capable of performing the above and an abnormality detection method for the vehicle periphery monitoring device.

The vehicle periphery monitoring device is usually attached to a front part or a rear bumper part of a vehicle. The inventor pays attention to the fact that the distance between the vehicle periphery monitoring device mounted on the vehicle and the ground is substantially constant, measures the reception level of the reflected wave with the ground as a target, and receives the reflected wave If the reception level range at normal time is set in advance based on the above, it is found that the abnormality of the vehicle periphery monitoring device can be determined by comparing the normal reception level range with actual measurement data with respect to the ground. It came to complete.

That is, the vehicle periphery monitoring device (1) according to the present invention is a vehicle periphery monitoring device including a transmission unit that transmits radio waves and a reception unit that receives reflected waves of the transmitted radio waves. It is characterized by comprising an abnormality judging means for judging whether or not there is an abnormality by comparing the reception level of the reflected wave of the radio wave transmitted toward the above and a preset normal reception level range.
According to the vehicle periphery monitoring device (1), by comparing the reception level of the reflected wave of the radio wave transmitted toward the ground when the engine is started with the normal reception level range, the abnormality of the device can be accurately detected. Judgment can be made. In addition, it is possible to quickly detect an abnormality when the engine is started before running the vehicle, and when there is no abnormality, it is in a state in which an accurate reception level can be detected, so highly reliable peripheral monitoring can be performed. it can.

In the vehicle periphery monitoring device (2) according to the present invention, in the vehicle periphery monitoring device (1), when the abnormality determination unit determines that the reception level of the reflected wave is out of the normal reception level range. It is characterized by judging that there is an abnormality.
According to the vehicle periphery monitoring device (2), since it is determined that there is an abnormality when the reception level of the reflected wave is out of the normal reception level range, the abnormality determination can be accurately performed. .

Further, the vehicle periphery monitoring device (3) according to the present invention includes the vehicle periphery monitoring device (1) or (
In 2), the normal reception level range is determined based on a reference waveform set from a plurality of measured waveforms with respect to the ground, and the reference waveform is determined.
According to the vehicle periphery monitoring device (3), a normal reception level range suitable for evaluating an actual reception level is provided, and abnormality determination can be performed appropriately.

Further, the vehicle periphery monitoring device (4) according to the present invention includes the vehicle periphery monitoring device (1) or (
2), the normal reception level range is obtained from a plurality of measured waveforms with respect to the ground, the maximum value waveform having the largest reception level and the minimum value waveform having the smallest reception level, and the maximum value waveform is the upper limit of the normal range. The minimum value waveform is defined as the lower limit value of the normal range.
According to the vehicle periphery monitoring device (4), the normal reception level range in which the variation of the reception level is considered to the maximum is set, and it is possible to reliably detect that there is an abnormality, Accuracy can be increased.

Further, the vehicle periphery monitoring device (5) according to the present invention includes the vehicle periphery monitoring device (1) or (
2), the normal reception level range is determined by obtaining an average value waveform from a plurality of measured waveforms with respect to the ground, and raising and lowering the average value waveform.
According to the vehicle periphery monitoring device (5), a normal reception level range in which the average waveform is raised and lowered is set, and a reliable range for determining whether or not there is an abnormality is set. Can be set.

The vehicle periphery monitoring device (6) according to the present invention includes the vehicle periphery monitoring device (1) to (5).
), A notification means for notifying that there is an abnormality when the abnormality determination means determines that there is an abnormality is provided.
According to the vehicle periphery monitoring device (6), when it is determined by the abnormality determining means that there is an abnormality, it is possible to promptly notify the occupant that there is an abnormality.

In addition, the abnormality detection method (1) for the vehicle periphery monitoring device according to the present invention is an abnormality detection method for the vehicle periphery monitoring device that detects an object existing around the vehicle based on the reception level of the reflected wave of the transmitted radio wave. A process of transmitting a radio wave toward the ground when the engine is started, a process of receiving a reflected wave of the radio wave and detecting a reception level of the reflected wave, a reception level of the reflected wave, and setting in advance And a process of detecting an abnormal operation by comparing with a normal reception level range.

According to the abnormality detection method (1) of the vehicle periphery monitoring device, the reception level of the reflected wave of the radio wave transmitted toward the ground when the engine is started is compared with the normal reception level range. Abnormalities can be detected accurately. In addition, an abnormality can be detected as soon as possible when the engine is started before the vehicle is driven, and if there is no abnormality, it is in a state where an accurate reception level can be detected, so highly reliable peripheral monitoring is performed. The Rukoto.

Embodiments of a vehicle periphery monitoring device according to the present invention will be described below with reference to the drawings. FIG.
These are the block diagrams which showed roughly the principal part of the vehicle periphery monitoring apparatus which concerns on embodiment. However, here, components having the same functions as those in the vehicle periphery monitoring device (radar 1) shown in FIG.

In the figure, reference numeral 11 denotes a vehicle periphery monitoring device 11 that is mounted on a vehicle and monitors an object existing in front of the vehicle. The vehicle periphery monitoring device 11 includes a processing unit 12, a transmission unit 3, The receiving means 4 is comprised.

Further, the driving means 13 is provided in the vehicle periphery monitoring device 11, and the driving means 13 switches the radio wave transmission / reception direction of the vehicle periphery monitoring device 11 to the ground direction when the engine is started, and returns to the original position after a certain time. It is possible to perform a return operation.

The processing unit 12 is composed of a microcomputer, and acquires data relating to the reception level of the reflected pulse detected by the receiving unit 4, and includes an object determining unit 2a, an abnormality determining unit 12a, and a notifying unit. 12b and a memory 12c.

The abnormality determination unit 12a compares the reception level of the reflected pulse of the electromagnetic pulse transmitted toward the ground when the engine is started with a preset normal reception level range, and the received level of the reflected pulse is the normal reception level. When it is out of the level range, it is judged that there is an abnormality.

Further, data related to the normal reception level range is stored in the memory 12c, and the normal reception level range is determined based on a reference waveform set from a plurality of measured waveforms with respect to the ground. . For example, a radar that operates normally is attached to a test vehicle, etc., and the reception levels of reflected waves from various different grounds (asphalt, soil, gravel, etc.) are actually measured, and obtained based on the data of the reception levels. The data within the normal reception level range is stored in the memory 12c.

The notification unit 12b generates a warning sound to notify the occupant that there is an abnormality when the abnormality determination unit 12a determines that there is an abnormality, or warns a signal for turning on a warning lamp (not shown). A process of outputting to a buzzer and a warning lamp (both not shown) is performed.

Next, an abnormality detection method for the vehicle periphery monitoring device 11 according to the embodiment will be described. FIG.
It is the figure which showed the arrangement | positioning state of the vehicle periphery monitoring apparatus 11 mounted in the vehicle, (a) is normal time, (b) has shown the state at the time of engine starting.

As shown in FIG. 2 (a), during normal times (during travel other than when the engine is started or when the vehicle is stopped), the radio wave transmission / reception surface 11a of the vehicle periphery monitoring device 11 is directed forward of the vehicle. On the other hand, when the engine is started, the radio wave transmission / reception surface 11a of the vehicle periphery monitoring device 11 is directed to the ground as shown in FIG. 2 (b).

At the time of starting the engine, an electromagnetic pulse is transmitted from the transmission means 3 toward the ground with the radio wave transmission / reception surface 11a of the vehicle periphery monitoring device 11 facing the ground, and the reflected electromagnetic pulse is reflected from the ground. The pulse is received by the receiving means 4, and the reception level of the received reflected pulse is detected.

Data relating to the reception level of the reflected pulse detected by the receiving means 4 is acquired by the processing unit 12, and the data relating to the reception level is compared with data in the normal reception level range read from the memory 12c. Is detected depending on whether or not is out of the normal reception level range.

FIG. 3 is a diagram for explaining an abnormality determination process performed by the processing unit 12 in the vehicle periphery monitoring apparatus 11 according to the embodiment. FIG. 3A shows a normal reception level range and reception of a reflected pulse at normal time. (B) shows the relationship between the normal reception level range and the reception level of the reflected pulse at the time of abnormality. The vertical axis represents the reception level and the horizontal axis represents time.

As shown in FIG. 3A, the reception level of the reflected pulse of the radio wave transmitted toward the ground when the engine is started (the waveform indicated by the solid line) is the normal reception level range (the broken line determined based on the reference waveform) If it does not deviate from the section indicated by (), it is judged as normal.

On the other hand, as shown in FIG. 3B, if the reception level of the reflected pulse of the electromagnetic pulse transmitted toward the ground when the engine is started is out of the normal reception level range, the vehicle periphery monitoring device 11 is It is judged that there is an abnormality.

Next, the abnormality determination processing operation performed by the processing unit 12 in the vehicle periphery monitoring apparatus 11 according to the embodiment will be described based on the flowchart shown in FIG.
First, in step S1, it is determined whether or not the engine has been started. If it is determined that the engine has not been started, the process ends. If it is determined that the engine has been started, the process proceeds to step S2.

In step S2, a drive signal for lowering the vehicle periphery monitoring device 11 is sent to the drive means 13, and then the process proceeds to step S3. In step S3, a process for acquiring data related to the reception level of the reflected pulse of the electromagnetic pulse transmitted toward the ground is performed from the receiving means 4, and the process proceeds to step S4.

In step S4, the data of the normal reception level range is read from the memory 12c, the process of comparing the reception level of the reflected pulse acquired from the receiving means 4 and the normal reception level range is performed, and the process proceeds to step S5.

In step S5, it is determined whether or not the reception level of the reflected pulse is out of the normal reception level range, and if it is determined that the reception level of the reflected pulse is not out of the normal reception level range (that is, normal), step S5 is performed. On the other hand, if it is determined that the reception level of the reflected pulse is out of the normal reception level range, the process proceeds to step S6. In step S6, a notification process, that is, a process of generating a warning sound or outputting a signal for turning on the warning lamp is performed, and then the process proceeds to step S7, and a drive signal for directing the vehicle periphery monitoring device 11 is generated. After sending, the process is terminated.

According to the vehicle periphery monitoring device 11 according to the above-described embodiment, the reception level of the reflected pulse of the electromagnetic pulse transmitted toward the ground when the engine is started is compared with a preset normal reception level range. Thus, the abnormality of the vehicle periphery monitoring device 11 can be accurately determined. In addition, an abnormality can be detected as soon as possible when the engine is started before the vehicle is driven, and if there is no abnormality, a highly accurate reception level can be detected, so highly reliable peripheral monitoring is performed. be able to.

In addition, since it is determined that there is an abnormality when the reception level of the reflected pulse is out of the normal reception level range, the accuracy of abnormality detection can be improved, and the normal reception level range stored in the memory 12c. However, since a reference waveform is set from a plurality of measured waveforms with respect to the ground and determined based on the reference waveform, a normal reception level range suitable for evaluating an actual reception level is provided. The abnormality determination can be appropriately executed. In addition, when it is determined that there is an abnormality, it is possible to promptly notify the passenger that there is an abnormality in the vehicle periphery monitoring device 11.

In the vehicle periphery monitoring device 11 according to the above embodiment, the vehicle periphery monitoring device 11 body is driven by the drive means 13 so that the radio wave transmission / reception surface 11a of the vehicle periphery monitoring device 11 faces the ground when the engine is started. However, the driving method of the vehicle periphery monitoring device 11 at the time of starting the engine is not limited to this, and the radio wave transmitted from the transmission means 3 at the time of starting the engine is transmitted toward the ground. It suffices if the receiving means 4 can receive a reflected wave from the ground.

In the vehicle periphery monitoring apparatus 11 according to the above-described embodiment, the normal reception level range stored in the memory 12c sets a reference waveform from a plurality of measured waveforms with respect to the ground, and is determined based on the reference waveform. However, in another embodiment, the normal reception level range is set such that the maximum waveform having the highest reception level is measured from a plurality of measured waveforms with respect to the ground as the upper limit, and the minimum value waveform having the lowest reception level is set as the lower limit. It may be determined as a value. According to such a configuration, a range in which reception level variation is considered as much as possible is set as the normal reception level range, so that it is possible to execute an error determination without error, and to improve the accuracy of the error determination. Can be increased.

In still another embodiment, the normal reception level range may be determined by obtaining an average value waveform from a plurality of measurement waveforms with respect to the ground and raising and lowering the average value waveform. According to such a configuration, a range in which the average value waveform is raised and lowered is set as the normal reception level range, and a highly reliable tolerance range is set to determine that it is abnormal. Can do.

Moreover, in the vehicle periphery monitoring apparatus 11 according to the above embodiment, data related to the normal reception level range is stored in advance in the memory 12c. However, in another embodiment, the normal reception level range is set. You may be able to do it.

For example, when a vehicle periphery monitoring device is newly attached to the vehicle or when the vehicle height is changed, the radio wave transmission / reception surface of the vehicle periphery monitoring device is driven toward the ground by a predetermined setting operation. The process of transmitting the electromagnetic pulse from the transmission means 3 and measuring the reception level of the reflected pulse from the ground is executed a plurality of times, and the normal reception level range described above is obtained based on the measured data and stored in the memory. You may come to memorize. According to this configuration, for example, the normal reception level range can be set at the time of attachment to a vehicle, and the normal reception level range corresponding to each vehicle can be appropriately set when necessary.

In the vehicle periphery monitoring device according to the above-described embodiment, the case where a pulse radar that transmits electromagnetic pulses as radio waves is used has been described. However, the vehicle periphery monitoring device according to the present invention is limited to the pulse radar. Any device that can measure the reception level of the reflected wave is acceptable. For example, a device that transmits a continuous wave signal such as a CW radar may be employed.

The vehicle periphery monitoring device according to the present invention can be applied to a preventive safety system that prevents a collision with an obstacle such as a vehicle or a pedestrian, and an occupant protection system that protects an occupant when the vehicle collides with an obstacle. The reliability of the system can be improved by accurately determining the abnormality of the vehicle periphery monitoring device.

It is the block diagram which showed roughly the principal part of the vehicle periphery monitoring apparatus which concerns on embodiment of this invention. It is the figure which showed the arrangement | positioning state of the vehicle periphery monitoring apparatus mounted in the vehicle, (a) is normal, (b) has shown the state at the time of engine starting. It is a figure for demonstrating the abnormality judgment process which the process part in a vehicle periphery monitoring apparatus performs, (a) has shown the relationship between the normal reception level range and the reception level of the reflected pulse at the time of normal, (b ) Shows the relationship between the normal reception level range and the reception level of the reflected pulse at the time of abnormality. It is the flowchart which showed the abnormality determination processing operation which the process part in the vehicle periphery monitoring apparatus which concerns on embodiment performs. It is the block diagram which showed schematically the principal part of the conventional radar. It is the figure which showed the received waveform of the reflected pulse received with the conventional radar, (a) shows the waveform of the reception level more than a threshold value, (b) has shown the waveform of the reception level less than a threshold value.

Explanation of symbols

3 Transmitting means 4 Receiving means 11 Vehicle periphery monitoring device
12 processor 12a abnormality determination means

Claims (7)

A transmission means for transmitting radio waves;
In a vehicle periphery monitoring device comprising a receiving means for receiving a reflected wave of a transmitted radio wave,
It is provided with an abnormality judging means for judging whether or not there is an abnormality by comparing a reception level of a reflected wave of a radio wave transmitted toward the ground when the engine is started with a preset normal reception level range. A vehicle periphery monitoring device. 2. The vehicle periphery monitoring device according to claim 1, wherein the abnormality determination unit determines that there is an abnormality when the reception level of the reflected wave is out of the normal reception level range. 3. The vehicle according to claim 1, wherein the normal reception level range is determined based on a reference waveform set from a plurality of measurement waveforms with respect to the ground. 4. Perimeter monitoring device. In the normal reception level range, a maximum value waveform having the largest reception level and a minimum value waveform having the smallest reception level are obtained from a plurality of measurement waveforms with respect to the ground, and the maximum value waveform is the upper limit value of the normal range and the minimum value waveform. 3. The vehicle periphery monitoring device according to claim 1, wherein the value waveform is defined as a lower limit value of a normal range. 2. The normal reception level range is determined by obtaining an average value waveform from a plurality of measurement waveforms with respect to the ground, and raising and lowering the average value waveform.
Or the periphery monitoring apparatus for vehicles of Claim 2. 6. The vehicle periphery monitoring according to claim 1, further comprising notification means for notifying that there is an abnormality when the abnormality determination means determines that there is an abnormality. apparatus. An abnormality detection method for detecting an abnormal operation of a vehicle periphery monitoring device that detects an object existing around a host vehicle based on a reception level of a reflected wave of a transmitted radio wave,
A process of transmitting radio waves toward the ground when the engine starts,
Receiving a reflected wave of the radio wave and detecting a reception level of the reflected wave;
An abnormality detection method comprising: a step of detecting an abnormal operation by comparing a reception level of the reflected wave with a normal reception level range set in advance.

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