JP3066885B2 - Radar equipment for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radar system for a vehicle, and more particularly, to a method for quickly obtaining information when a preceding vehicle is replaced while traveling at a constant speed following a preceding vehicle. The present invention relates to a radar apparatus for a vehicle.

[0002]

2. Description of the Related Art Conventionally, an inter-vehicle distance between a host vehicle and a preceding vehicle is measured using a laser radar, and a relative speed between the preceding vehicle and the host vehicle is calculated from a temporal change in the distance. 2. Description of the Related Art There is known a system that performs inter-vehicle distance control or various alarm controls between a vehicle and a preceding vehicle.

[0003] In such a system, for example, a predetermined laser wave is emitted from a laser radar provided in the own vehicle, and is reflected by an appropriate reflecting means provided in a predetermined place of a preceding vehicle and returned. The time until the laser wave is received is measured, and the inter-vehicle distance between the preceding vehicle and the host vehicle is calculated from the time, and when the inter-vehicle distance is equal to or less than a predetermined value, a predetermined value is obtained. If an alarm is issued or if the vehicle is running at a constant speed, a predetermined deceleration operation is executed to ensure safe traveling of the vehicle.

In such a system, as described above, the inter-vehicle distance between the host vehicle and the preceding vehicle is measured by a laser radar. Depending on the cause, it contains considerable variation, that is, it contains ripples, while including such ripples,
If the corrected inter-vehicle distance between the own vehicle and the preceding vehicle is obtained, an error is included. Further, if the relative speed between the own vehicle and the preceding vehicle is obtained from such information, the temporal change amount of the corrected inter-vehicle distance is obtained. If the modified inter-vehicle distance is subjected to differential calculation processing, the result will contain an extremely large error.

[0005] In such a state, the laser cannot be put to practical use, and in order to prevent unnecessary fluctuation of the relative speed, in practice, the data of the inter-vehicle distance measured by the laser radar is appropriately provided in advance. The ripple is removed by applying a filter, for example, a low-pass filter, and the corrected inter-vehicle distance between the own vehicle and the preceding vehicle is obtained by using data output from the filter.

On the other hand, in such a system, a particularly problematic case is that the preceding vehicle is switched due to another vehicle interrupting between the own vehicle and the preceding vehicle, or because the own vehicle changes lanes. In such a case, the inter-vehicle distance between the host vehicle and the preceding vehicle may be rapidly reduced. In such a case, appropriate information indicating that the inter-vehicle distance has been sharply shortened is output accurately and promptly, and based on the result, it is necessary that the predetermined alarm means or deceleration means operate normally. There is.

In a system according to one conventional example, as shown in FIG. 5, a distance measurement means 2 calculates the distance from a laser sensor 1 which receives a reflected wave from a laser radar. The corrected inter-vehicle distance is calculated by the first calculating means 3 which measures the inter-vehicle distance, removes the ripple included in the inter-vehicle distance information and calculates the corrected inter-vehicle distance by using an appropriate filter, and obtains the corrected inter-vehicle distance. In this method, the modified inter-vehicle distance is differentiated to obtain a relative speed between the own vehicle and the preceding vehicle, and the appropriate control means 5 is operated based on the result. In order to remove the ripple from the distance information output from the inter-vehicle distance measuring means 2 by the filter means 3 as a means, the distance information is obfuscated, so the corrected inter-vehicle distance obtained from the filter means 3 is Since the change is slow, precisely that inter-vehicle distance between the host vehicle and the preceding vehicle is contracted to less than a predetermined distance, it is impossible to and quickly determined.

[0008] Naturally, the change in the relative speed between the host vehicle and the preceding vehicle obtained from the inter-vehicle distance information must be slower. By the way, as shown in FIG.
The output of the inter-vehicle distance measuring means 2 is determined in order to determine whether or not the preceding vehicle has been switched between the own vehicle and the preceding vehicle between the distance filter processing means 3 as the first arithmetic means and the distance filtering processing means 3. A preceding vehicle changeover judging means 6 for judging whether or not the preceding vehicle has been exchanged is provided, and from the distance information including the ripple obtained by the inter-vehicle distance measuring means 2,
When a specific condition is satisfied, it is set so as to determine whether or not the preceding vehicle has been replaced, and when it is determined that the preceding vehicle has been replaced, it is necessary to start control as a new vehicle. Therefore, under the control of the control means 7, only at that time, the distance information output from the inter-vehicle distance measuring means 2 is not filtered by the distance filter processing means 3 but is output from the inter-vehicle distance measuring means 2. The obtained raw information is determined as the corrected inter-vehicle distance, and is transmitted directly to the relative speed calculating means 4 as the second calculating means at the subsequent stage.

[0009] Thereafter, normal control, that is, the distance information is processed by the filter means 3. In other words, in the conventional system, when the inter-vehicle distance suddenly changes in the first calculating means 3 using the filter means, the filter processing is interrupted to determine the inter-vehicle distance. Then, the filter means 3 is intended to avoid a time delay for judging that the inter-vehicle distance has been sharply reduced.

The outline of the system will be described in more detail. As shown in the flowchart of FIG. 6, after the start, in step (1), the inter-vehicle distance measuring means 2 uses the laser radar device to connect with the own vehicle. The inter-vehicle distance between preceding vehicles is measured. In such a stage, the control means 7
The appropriate sampling means 8 is operated under the control of
For example, a sampling cycle is set to 100 ms, a laser radar is emitted for each sampling cycle, and the feedback time is measured by the inter-vehicle distance measuring means 2.

That is, the inter-vehicle distance at the time of the previous sampling is D _n-1 and the current inter-vehicle distance is D _n . Such information is indicated by a solid line a in the area P in FIG. Similarly, the relative speed between the host vehicle and the preceding vehicle is obtained by performing a differential operation on the inter-vehicle distance information by the second calculating means 4 as shown by a solid line c in the area Q in FIG. I have.

The inter-vehicle distance information and the relative speed information obtained by performing a filtering process by the first calculating means 3 on the inter-vehicle distance information and the relative speed information are represented by dotted lines b and d in the respective areas. And are shown. Next, step (2)
As described above, based on the inter-vehicle distance information output from the inter-vehicle distance measuring means 2, the preceding vehicle changeover judging means 6 judges whether or not the preceding vehicle has been exchanged. For example, when the difference between the inter-vehicle distances measured at each sampling period becomes a predetermined value, for example, 5 m or more, it is determined that the preceding vehicle has been replaced. That is, _assuming that the inter-vehicle distance at the previous sampling time is D _n−1 and the current inter-vehicle distance is D _n , the inter-vehicle distance information output from the preceding vehicle changeover determination means 6 is D _n −D
_{Expressed as n-1} .

Therefore, in step (2), D
_n− D_n-1If the condition of ≧ 5m is satisfied,
It is determined that the vehicle has been replaced. Therefore,
Whether the preceding vehicle has been replaced in Step (2)
And if NO, proceed to step (3)
The above-mentioned filter processing in the first calculating means 3 is executed,
Inter-vehicle distance information obtained from the inter-vehicle distance measuring means 2
D_n-1, D _nThe corrected inter-vehicle distance is calculated from each of
Is what you want.

The filter means 3 has, for example, an appropriate capacity.
Low-pass fill with appropriate time constant composed of resistor and resistor
It may be composed of data. In such a filter means 3
Examples of arithmetic processing include, for example, the previous sampling
Inter-vehicle distance information D obtained at the time_n-1The filter processing
The corrected inter-vehicle distance obtained by applying_n-1And this time
Inter-vehicle distance information D obtained at the time of sampling _nTo
The corrected inter-vehicle distance obtained by performing the filtering_nage
The corrected inter-vehicle distance_nIs the DF_n= (D_n+ 7 x DF_n-1) Performs the arithmetic processing represented by $ 8.

Next, proceeding to step (4), the corrected inter-vehicle distance D between the own vehicle and the preceding vehicle obtained in step (3) is obtained.
A predetermined time change is obtained by the second calculating means 4 from F _n-1 and DF _n . The second calculating means 4
The slope of the graph obtained from the corrected inter-vehicle distances DF _n−1 , DF _n, etc. is obtained by executing a differential operation process,
More specifically, for example, it may be obtained by executing the following calculation.

[0016] That is, in case of obtaining the amount of change between the current sampling period 100ms is, VR _n = - whereas _{(DF n DF n) ÷ 0.1s} (m / s), is YES in step (2) in case of,
Steps (3) and (4) are skipped and the routine proceeds to return. As described above, as described above, when it is determined that the preceding vehicle has been replaced, the information is directly applied to the inter-vehicle distance information output from the inter-vehicle distance measuring means 2 at the time of the sampling without filtering. The corrected inter-vehicle distance is used, and the relative speed is calculated based on the corrected inter-vehicle distance.

More specifically, in the processing stage corresponding to step (3), the inter-vehicle distance information D _n obtained at the time of this sampling is set as a corrected inter-vehicle distance DF _n. In the processing stage corresponding to step (4), the relative speed VR _n-1 obtained from the inter-vehicle distance information D _n-1 obtained at the previous sampling time is set as the current relative speed VR _n. become.

Then, returning from the return to the start, at the next sampling time point, the measurement by the inter-vehicle distance measuring means 2 is performed again in step (1), and based on the result, the preceding vehicle is again determined in step (2). Is determined by the preceding vehicle replacement determining means 6. In this case, the determination is NO. That is, at the time of the sampling, the preceding vehicle has already been replaced, and the difference in the inter-vehicle distance between the own vehicle and the preceding vehicle should be equal to or less than the above-described predetermined distance.

Therefore, in steps (3) and (4), normal filter processing is executed, and the relative speed is obtained. That is, in the present system, only the inter-vehicle distance at the time when the preceding vehicle is replaced is not filtered by the first calculating means, and the information output from the inter-vehicle distance measuring means 2 is directly calculated by the relative speed calculation. The relative speed is obtained by inputting the result to a second calculating means which is a means.
This executes normal processing.

The measurement result is indicated by a solid line A between the point X1 and the point X2 in the area R in FIG. 7, and when the preceding vehicle changeover judging means 6 judges that the preceding vehicle has been changed. Since the output value of the inter-vehicle distance measuring means 2 is output as it is as the inter-vehicle distance, the inter-vehicle distance between the host vehicle and the preceding vehicle suddenly increases as indicated by a solid line between points X1 and X2 in FIG. It shows that you are depressed.

Since the normal arithmetic processing is performed after the point X2 in the same manner as described above, a solid line graph showing the following distance output from the following distance measuring means 2 in the region R of FIG. a and the inter-vehicle distance b obtained by the filtering process
Is shown in FIG. On the other hand, in the area S, a graph in which the relative speed between the host vehicle and the preceding vehicle is obtained from the respective graphs indicating the inter-vehicle distance in the area R using the second calculating means 3. The solid line c indicates the relative speed obtained from the solid line a indicating the inter-vehicle distance, and the dotted line d indicates the relative speed obtained from the dotted line b indicating the smoothed inter-vehicle distance.

[0022]

The problem here is that in the respective processes after the calculation process of the inter-vehicle distance at the time when it is determined that the preceding vehicle has been replaced, that is, the point X2
In the following arithmetic processing, the relative speed c based on the inter-vehicle distance a obtained from the inter-vehicle distance measuring means 2 fluctuates extremely, whereas , The relative speed d based on the inter-vehicle distance b obtained by performing the filtering process of the first calculating means 3 is slowly falling, and the relative speed information obtained by the smoothing process and the actual relative speed information There will be a big difference between

The reason why both of them show substantially the same value is that the preceding vehicle changeover judging means 6 judges that the preceding vehicle has been changed from the time T1 and the time T2 when the delay time t has elapsed. Become. In other words, in the conventional system, when trying to accurately determine the inter-vehicle distance and the relative speed between the host vehicle and the preceding vehicle based on the information subjected to the smoothing process, particularly when determining the relative speed, It will take a considerable delay time to detect the correct relative speed.

The existence of such a delay time is particularly caused when another vehicle interrupts between the own vehicle and the preceding vehicle during traveling at a constant speed, or when the vehicle enters the overtaking lane, within a short distance in front of the vehicle. When there is another vehicle, the distance between the host vehicle and the preceding vehicle and the relative speed between the host vehicle and the preceding vehicle are promptly and accurately checked, and an alarm is immediately generated or a predetermined deceleration is performed. It is necessary to execute the operation, but if such a problem exists, it is not possible to take prompt action, threatening the safe driving of the vehicle and causing a dangerous state.

An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a vehicular radar device capable of quickly and accurately determining the inter-vehicle distance and relative speed even after a vehicle is switched. It is.

[0026]

The present invention employs the following technical structure to achieve the above object. That is, an inter-vehicle distance measuring means for measuring an inter-vehicle distance between the own vehicle and the preceding vehicle, a preceding vehicle replacement determining means for determining whether or not the preceding vehicle has been replaced by another vehicle, and an inter-vehicle distance from the inter-vehicle distance measuring means. The filter means for smoothing the data, the calculating means for calculating the corrected inter-vehicle distance based on the inter-vehicle distance data smoothed by the filter means, and the preceding vehicle replacement determining means indicate that the preceding vehicle has been replaced. When the exchange information is detected, the vehicle radar device includes control means for reducing a degree of the smoothing process in the filter means for at least a predetermined time.

[0027]

According to the present invention, in the conventional system,
The delay time t generated when obtaining the inter-vehicle distance and the relative speed between the own vehicle and the preceding vehicle based on the information obtained by performing the smoothing process is configured to be as short as possible. Even if you use the information that performed the
It is possible to quickly and accurately check the inter-vehicle distance and the relative speed between the host vehicle and the preceding vehicle, immediately generate an alarm, and ensure safe driving of the host vehicle.

As a specific example for this purpose, for example, a filter means for smoothing the inter-vehicle distance data from the inter-vehicle distance measuring means and a corrected inter-vehicle distance is calculated based on the inter-vehicle distance data smoothed by the filter means. For a predetermined period after the preceding vehicle changeover judging means 6 judges that the preceding vehicle has been changed, the degree of the smoothing process in the filter means is reduced. The relative speed information obtained based on the inter-vehicle distance information obtained by performing the smoothing process is approximated as much as possible to the actual relative speed obtained based on the corrected inter-vehicle distance information that does not perform the smoothing process. After the predetermined period has elapsed, the time constant of the filter means may be returned to the predetermined time constant gradually or stepwise. It is.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A specific example of a vehicular radar device according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram illustrating an example of a configuration of a vehicular radar device according to the present invention. In FIG. 1, a distance between a host vehicle 20 and a preceding vehicle 21 is measured using a laser radar 1 having a laser sensor. In a system that performs a predetermined filter process on the measurement information, calculates a corrected inter-vehicle distance and a relative speed between the own vehicle and the preceding vehicle, and performs inter-vehicle distance control and various alarms, Means 1, sampling control means 8, inter-vehicle distance measuring means 2 for measuring the inter-vehicle distance between own vehicle 20 and preceding vehicle 21, preceding vehicle switching determining means 6 for judging whether or not preceding vehicle 21 has been exchanged,
Filter means 9 having at least two types of time constants,
The first calculating means 3 for calculating the corrected inter-vehicle distance from the output value of the inter-vehicle distance measuring means 2 using the filter means 9, and the own vehicle 20 and the preceding vehicle 21 are calculated from the output value of the first calculating means 3. Calculating means 4 for calculating the relative speed between the control means and the control means 7 for controlling the operation of each means in relation to each other.
When the information indicating that the preceding vehicle 21 has been replaced is output from the preceding vehicle replacement determining means 6 at the time of one sampling, the control means 7 In response to the output information from the judging means 6, at the sampling time point or at a time point immediately after the sampling time point, the first calculating means 3 calculates the inter-vehicle distance information detected by the inter-vehicle distance measuring means 2. The vehicular radar device controls the arithmetic operation to be stopped and the arithmetic operation by the first arithmetic means 3 to be restarted with respect to the inter-vehicle distance information detected from the time of sampling thereafter.

That is, the basic technical configuration of the vehicular radar apparatus according to the present invention is as follows. For example, the time constant of the filter means 9 in the first arithmetic means 3 is changed to change the time constant of the preceding vehicle. For a predetermined period from the time when the switching determination means 6 determines that the preceding vehicle 21 has been switched, the magnitude of the time constant in the filter means 9 is set small,
The relative speed information obtained based on the inter-vehicle distance information obtained by performing the smoothing process by reducing the degree of the smoothing process is obtained based on the corrected inter-vehicle distance information not performing the smoothing process. And to return the time constant of the filter means 9 to the predetermined time constant gradually or stepwise after the predetermined period has elapsed. It is.

More specifically, the filter means 9 constituting the first arithmetic means 3 in the vehicular radar device of the present invention comprises, for example, a plurality of filter devices. The filter devices may be configured to have different time constants from each other, or may be configured from one filter device, and the time constant of the filter device may be arbitrarily determined by a predetermined process. It may be configured to be changeable.

The time constant (CR) in the filter means 3 used in the present invention needs to be set to at least two values having different sizes.
As long as there are two or more types, any number may be set. For example, three filter means 3 # 1, 3 # 2, which are set to three different (large, medium, small) time constants,
By setting 3─3 and setting the smallest time constant so that an output close to the original signal is generated, the delay of the output from the filter means is minimized.

The largest time constant is set to a level at which a delay time which maximizes the effect of the smoothing process to be adopted in the present system can be achieved. Can be set to any level. Then, in the present invention, as shown in FIG. 3A, after the preceding vehicle changeover judging means 6 judges that the preceding vehicle has been changed, under the control of the control means 7,
The inter-vehicle distance measuring means 2 is sampled during a predetermined period.
First, a smoothing process is performed by applying the filter means 3 # 1 having the smallest time constant to the inter-vehicle distance information output from
After that, the same processing is executed by switching to the filter means 3 # 2, 3 # 3 having a larger time constant.

In such a case, each time a predetermined time elapses, the filter means having the time constant which is sequentially increased may be selected in order. If necessary, the filter means having the intermediate level time constant may be skipped. Thus, a filter means having the maximum time constant may be used. Further, in the present invention, as shown in FIG. 3B, as described above, it is possible to use one filter means 3 whose time constant can be arbitrarily changed. By the same processing method as described above, it is also possible to perform processing while appropriately changing the time constant under the control of the control means 7.

In the present invention, the timing at which the smoothing process is performed by applying the filter means 3 having the smallest time constant is not particularly limited. For 0.2 seconds after the sampling point that occurs immediately after it is determined that the replacement has been performed, the smoothing process is performed by applying the filter means 3 having the smallest time constant, and thereafter, the time constant is appropriately increased sequentially. What is necessary is just to select a suitable filter means sequentially.

As another specific example of the present invention,
For example, as shown in FIG. 3 (C), filter means 3 # 1, 3 # 2, 3 # 3 for controlling the above three time constants are provided in parallel, and The outputted inter-vehicle distance information is input to the three types of filter means simultaneously and in parallel, and the corrected inter-vehicle distance is individually output from each of the three types of filter means. After determining that the corrected inter-vehicle distance output from the filter means 3 # 1 having a small time constant is used by the filter selecting means 10 every time a predetermined period elapses,
Filter means 3─2, which are selected and sequentially increase in time constant,
Select the corrected inter-vehicle distance output from 3 か ら 3,
The data may be input to the second calculation means 4.

For this reason, in the present invention, for example, the control means 7 is provided with a timer means 11 and responds to the output from the preceding vehicle replacement determining means 6 that the preceding vehicle 21 has been replaced. It is preferable to sequentially measure the above-mentioned predetermined time, output a predetermined control signal to the filter selecting means 10 having an appropriate configuration, and execute the above processing.

Further, as described above, the control means 7 responds to the output of the information indicating that the preceding vehicle 21 has been replaced by the preceding vehicle replacement determination means 6 to change the time constant of the filter means 3. It may be configured to execute an operation of changing. That is, the control means according to the present invention responds to the output of the information indicating that the preceding vehicle has been switched from the preceding vehicle replacement determining means 6 in response to the output of a plurality of filter means 3 having different time constants. It is also preferable to be configured to execute an operation of selecting one of 1, 3, 2 and 3.

FIG. 2 shows the corrected inter-vehicle distance and the corrected relative speed between the host vehicle and the preceding vehicle measured using the vehicle radar device according to the present invention. That is, the point X in FIG.
In and after 2, the filter means 3 # 1 having a small time constant level and the time constant level is medium with respect to the solid line graph a indicating the headway distance output from the headway distance measurement means 3. The corrected inter-vehicle distances output by the smoothing operation from the filter means 3 # 2 and the filter means 3 # 3 having a large time constant level are indicated by dotted line graphs e, f, and g, respectively.

From this graph, it can be seen that the corrected inter-vehicle distance processed by the filter means 3 # 1 having a small time constant is signal information very close to the actual inter-vehicle distance information, and the delay time is small. . Further, in the vehicle radar device according to the present invention, a filter having a different time constant is appropriately employed according to the predetermined time elapse, or the time constant of the filter means is appropriately determined in the corrected inter-vehicle distance obtained as described above. The relative speed between the host vehicle and the preceding vehicle obtained by executing the second arithmetic processing is shown in a dotted line graph h in FIG. 2. Graph c showing the actual relative speed between the own vehicle and the preceding vehicle
It is found that the delay time is very short.

It can be seen that the graph c by such processing is significantly improved from the corrected relative velocity graph d obtained by the conventional method in FIG. as a result,
In the related art, the delay time t is required until the corrected relative speed matches the actual relative speed. In the present invention, however, the two match at time T3. , And the delay time can be significantly reduced to t ′ as compared with the conventional case.

Next, the procedure in the inter-vehicle distance and relative speed control system using the vehicle radar device according to the present invention will be described with reference to the flowchart shown in FIG. In the following specific example, three kinds of filter means 3 # 1, 3 # 2, 3 # 3 having different time constants are previously arranged in series, and a predetermined arithmetic processing An example is shown in which information is output and the filter means is selected in a predetermined order every time a predetermined time elapses.

That is, after the start, the operations in steps (1) and (2) are the same as those in the conventional method shown in FIG. In step (2), it is determined whether or not the preceding vehicle has been replaced. If NO, the process proceeds to step (3), in which the first time constant, which is one of the first calculation means, is the smallest. The arithmetic processing is executed using the filter means 3 # 1, and the actual inter-vehicle distance information D _n obtained from the inter-vehicle distance measuring means 2 and the corrected inter-vehicle distance DFS _n-1 obtained at the previous sampling time are used to calculate the current time. At the time of sampling
The corrected inter-vehicle distance DFS _n is obtained by calculation from, for example, the following relational expression.

[0044] _{DFS n = (D n + DFS} n-1) ÷ 2 . In step (4), the second filtering unit 3 for the time constant which is one of the first arithmetic means is in the intermediate level ─
2, the same arithmetic processing is performed, and from the actual inter-vehicle distance information D _n obtained from the inter-vehicle distance measuring means 2 and the corrected inter-vehicle distance DFM _n-1 obtained at the previous sampling time,
Corrected inter-vehicle distance DFM at the time of this sampling
For example, _n is calculated from the following relational expression.

DFM _n = (D _n + 3 × DFM _n-1 ) ÷ 4 Further, the process proceeds to step (5), where the second time constant, which is one of the first calculation means, is at the highest level. The same arithmetic processing is executed using the filter means 3 # 2, and the actual inter-vehicle distance information D _n obtained from the inter-vehicle distance measuring means 2 and the corrected inter-vehicle distance DFB _n-1 obtained at the previous sampling time point.
From, in the present sampling point, the correction vehicle distance DFB _n, for example, those obtained by calculation from the following equation.

DFB _n = (D _n + 7 × DFB _n-1 ) ÷ 8 Next, the process proceeds to step (6), where the count value of the timer means 11 is read, and the preceding vehicle changeover judging means 6 determines whether the preceding vehicle has changed. It is determined whether or not a predetermined time (first time) Ta has elapsed from the time of determining whether or not the replacement has been performed. If the predetermined time (first time) Ta or less has elapsed, that is, Y
If it is ES, the process proceeds to step (10), and the corrected inter-vehicle distance D between the own vehicle and the preceding vehicle obtained in step (3) is obtained.
A predetermined time change from FS _n is obtained in the second calculating means 4 to obtain a relative speed.

The processing method in the second calculating means 4 is as follows.
It is the same as the conventional method. If it is determined in step (6) that the predetermined time (first time) Ta, for example, 0.2 seconds, has elapsed, that is, if NO, the process proceeds to step (7). The preceding vehicle replacement determining means 6
It is determined whether or not a predetermined time (second time) Tb has elapsed from the time when it was determined whether the preceding vehicle has been replaced (Tb> Ta, for example, Tb is 1.0 second, etc.).
If the predetermined time (second time) is equal to or more than Ta and equal to or less than Tb, that is, if YES, the process proceeds to step (9), and the process proceeds to step (4). determined at the modified vehicle distance DFM _n predetermined temporal change to the second arithmetic means 4, and requests relative speed.

Thereafter, if it is determined in step (6) that the predetermined time (second time) Tb has elapsed,
That is, if NO, the process proceeds to step (8), and the corrected inter-vehicle distance D between the own vehicle and the preceding vehicle obtained in step (5) is obtained.
The predetermined time change from FB _n is obtained by the second calculating means 4 to obtain the relative speed.

[0049]

As described above, according to the present invention, it is possible to shorten the time lag when detecting an accurate relative speed between the host vehicle and the preceding vehicle, and there is a change of the preceding vehicle. Even after the determination is made, it is possible to obtain a vehicular radar device that can quickly and accurately determine the inter-vehicle distance and the relative speed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a specific example of a vehicular radar device according to the present invention.

FIG. 2 is a graph showing a corrected inter-vehicle distance and a corrected relative speed obtained using the vehicular radar device according to the present invention.

FIG. 3 is a block diagram illustrating an example of arrangement of filter means used in the vehicular radar device according to the present invention.

FIG. 4 is a flowchart illustrating an operation procedure in the vehicle radar device according to the present invention.

FIG. 5 is a block diagram for connecting a schematic configuration of a conventional vehicle radar device.

FIG. 6 is a flowchart illustrating an operation procedure in a conventional vehicle radar device.

FIG. 7 is a graph showing a corrected inter-vehicle distance and a corrected relative speed obtained by using a conventional vehicle radar device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Laser radar 2 ... Inter-vehicle distance measuring means 3 ... Calculating means, corrected inter-vehicle distance calculating means (first calculating means) 4 ... Relative speed measuring means, (second calculating means) 5 ... Control device 6 ... Switching of preceding vehicles Judgment means 7 Control means 8 Sampling means 9 Filter means 10 Filter selection means 11 Timer means

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuya Sasaki 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Yasuo Imai 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Hironori Miyakoshi 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (56) References JP-A-4-318700 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , (DB name) G08G 1/16 G01S 17/93 B60K 31/00 G01S 13/93

Claims (7)

(57) [Claims] An inter-vehicle distance measuring means for measuring an inter-vehicle distance between a host vehicle and a preceding vehicle; a preceding vehicle replacement determining means for determining whether or not the preceding vehicle has been replaced by another vehicle;
A filter means for smoothing the inter-vehicle distance data from the inter-vehicle distance measuring means, a calculating means for calculating a corrected inter-vehicle distance based on the inter-vehicle distance data smoothed by the filter means, and the preceding vehicle replacement determining means Control means for reducing the degree of smoothing processing in the filter means for at least a predetermined time upon detecting replacement information indicating that the preceding vehicle has been replaced. apparatus. 2. The vehicle radar device according to claim 1, wherein said filter means comprises a plurality of filter devices, each of which has a different time constant. 3. The vehicle according to claim 1, wherein said filter means is constituted by one filter device, and is configured such that a time constant of said filter device can be arbitrarily changed. Radar equipment. 4. The control means includes timer means which operates in response to the output of information indicating that the preceding vehicle has been replaced from the preceding vehicle change determination means. 2. The vehicle radar device according to 1. 5. The control means executes an operation of changing a time constant of the filter means in response to an output of information indicating that a preceding vehicle has been replaced from the preceding vehicle change determination means. The vehicle radar device according to claim 3, wherein: 6. The control means, in response to an output of information indicating that the preceding vehicle has been replaced from the preceding vehicle replacement determination means, controls any one of the plurality of filter means having different time constants. 3. The vehicle radar device according to claim 2, wherein the selecting operation is performed. 7. The control means, in response to a change in output information from the timer means, sequentially changes the time constant in the filter means or a plurality of different time constants in the filter means. 7. The vehicle radar device according to claim 2, wherein one of said filter means is sequentially selected.