JP3473679B2 - Object position detection device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object position detecting device, and more specifically, it emits radio waves such as millimeter waves toward an object,
The present invention relates to an object position detection device that detects the position of an object based on the reception state of reflected waves.

[0002]

2. Related Background Art This kind of object position detecting device is mounted on a vehicle, for example, and is used to detect a preceding vehicle, etc., and when the inter-vehicle distance obtained from the detected information is insufficient, it is driven by voice. A person is warned, or tracking control for automatically accelerating and decelerating the vehicle based on the detected information is executed to maintain an appropriate inter-vehicle distance.

To detect a preceding vehicle, a radio wave radar using a millimeter wave or the like or a laser radar using an infrared laser is used, and a reflected wave reflected by the preceding vehicle when these radio waves or lasers are emitted forward. Is received, and the position of the preceding vehicle is determined based on the distribution of the reflection level according to the required time and the reception angle at that time. The laser radar is easy to focus a beam, and a clear reflection level distribution is obtained, which is excellent in detection accuracy, but has a drawback that it is easily reflected by rain, fog, or the like and becomes undetectable.

On the other hand, the radio wave radar is hard to be affected by the above-mentioned diffuse reflection, but due to its nature, the diffusion of the beam is inevitable to some extent, so that the distribution of the received reflection level becomes unclear and the detection accuracy is low. Will be inferior. To compensate for this drawback, measures such as converging the beam or increasing the number of beams can be considered, but these hardware-based measures lead to a rise in the manufacturing cost, so in general, they vary depending on the filtering method. We are trying to improve detection accuracy by implementing software measures that suppress elements.

[0005]

However, as is well known, the suppression of the variable elements by the filter processing means that the past data is added to the new detection data, and
The responsiveness tends to deteriorate in exchange for the improvement in detection accuracy. For example, when the averaging process is applied as the filtering process, the detection information of the radio wave radar is averaged by the data of a predetermined number of times in the past, but the detection information obtained is stable if more past data is used. However, since the detection accuracy is improved, the responsiveness is deteriorated because it is greatly affected by the past data, and the advantages and disadvantages of the two conflict with each other.

It is an object of the present invention to provide an object position detecting device which can carry out appropriate filter processing on detection information of a radio wave radar and can realize both high detection accuracy and high responsiveness. .

[0007]

In order to achieve the above object, according to the invention of claim 1 , the X-coordinate and the Y-coordinate of the object are determined by the coordinate determination means based on the detection information of the radio wave type radar means. The width of the object in the Y coordinate direction is estimated by the width estimating means, and the reliability of the Y coordinate is determined by the reliability determining means based on whether the Y coordinate is located within the estimated width range. The degree of influence of the past data on the Y coordinate is changed according to the reliability, and Y is obtained by the filter processing means.
Configured to filter coordinates. Since the radio wave from the radar means is reflected by the object and received, the Y-coordinate is frequently located within the width of the object, and when the law is satisfied, the Y-coordinate of this time is highly reliable, and the Y-coordinate with the past data. Since it can be estimated that the relationship is high, the filter processing is performed so that the influence of the past data is large, and the detection accuracy is improved by stabilizing the Y coordinate. Conversely, the Y coordinate is not located within the width of the object. Sometimes, it can be estimated that the reliability of the Y coordinate this time is low and the relation with the past data is low. Therefore, the filtering process is performed so that the influence degree of the past data is small, and the responsiveness of the Y coordinate is improved. It is possible to plan. In the invention of claim 2,
Is when the Y coordinate is not located within the estimated width of the object.
Filter to reduce the influence of past data.
The processing means is configured to filter. Yo
And the Y coordinate is not located within the estimated width of the object
If it is determined that the coordinates are not reliable, past data
Filtering is performed with a small influence degree of
It is possible to improve the responsiveness of the Y coordinate. Claim
According to the third aspect of the invention, based on the detection information of the radio wave type radar means,
The X-coordinate and Y-coordinate of the object by the coordinate determination means.
The difference between the current value and the previous value of the Y coordinate of the object.
The estimation means sequentially updates in the increasing direction, and the Y coordinate direction of the object
The width is estimated and the Y coordinate is located within the estimated width.
Based on whether or not to perform
The reliability is judged, and the error related to the Y coordinate is determined according to the reliability.
By changing the influence degree of the old data,
It was configured to filter the Y coordinate. Radar means
Since the radio wave from is reflected by the object and received, the Y coordinate is
Frequently located within the width of the object . The width estimation means Y seat
Various values as the difference between the current value and the previous value depending on the fluctuation of the mark
Is calculated, but statistically, the Y coordinate is the width of the object.
There is a difference when it fluctuates greatly from one end to the other end of
Therefore, the width in the Y coordinate direction, which is almost the same as the actual width of the object, is estimated.
Is determined. And when the Y coordinate is located within the width of the object
The reliability of Y coordinate this time is high, and the relation with past data is
Since it can be estimated that the connectivity is high, the influence of past data is large.
By filtering so that
In order to improve the detection accuracy, the Y coordinate is located within the width of the object.
If not, the reliability of Y coordinate this time is low,
It can be assumed that the relationship with the data is low, so past data
The Y-coordinate of
It is possible to improve responsiveness.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The object position detecting device of the present invention will now be described in detail with respect to a tracking control device for accelerating and decelerating the own vehicle based on the information of the preceding vehicle detected by the radio wave radar to maintain an appropriate inter-vehicle distance. An example of the implementation will be described. As shown in the overall configuration diagram of FIG. 1, a radio wave radar 1 as a radar means is mounted on the front part of the vehicle, and the radio wave radar 1 emits a millimeter wave in the form of a beam toward the front to prevent a preceding vehicle or an obstacle. Receive millimeter waves reflected by objects. A CCD camera 2 is attached to the ceiling of the passenger compartment, and the CCD camera 2 detects obstacles on the road, lanes (white lines), and the like.

A throttle actuator 5 is connected to a throttle valve 4 of an engine 3 mounted on a vehicle,
The throttle actuator 5 opens and closes the throttle valve 4 according to the accelerator operation by the driver. Service brakes 8 such as disc brakes are provided on front wheels 6 and rear wheels 7 of the vehicle, and each service brake 8 is provided with a brake pedal 10 via a master cylinder 9 having a negative pressure booster.
The hydraulic pressure generated in the master cylinder 9 in response to the brake operation by the driver is supplied to each service brake 8 to apply a braking force to each wheel 6, 7. Further, the master cylinder 9 is provided with a brake actuator 11 to generate hydraulic pressure in the master cylinder 9 regardless of the pedal operation of the driver.

On the other hand, in the passenger compartment, an input / output device (not shown), a storage device (ROM, RAM, BURAM, etc.) used for storing control programs, control maps, etc., a central processing unit (CPU), a timer counter, etc. are provided. An ECU (electronic control unit) 14 equipped with the ECU 14 is installed.
In addition to the overall control of the engine 3, the tracking control described later is executed based on the detection information of the radio wave radar 1. EC
The radio wave radar 1 and the CCD camera 2 are connected to the input side of U14, and a tracking control set switch 16 for instructing execution of tracking control provided near the steering wheel 15 and left and right rear wheels which are driven wheels are provided. Wheel speed Vs of wheel 7
Various sensors such as a pair of wheel speed sensors 18 for detecting the vehicle speed are connected. Further, the throttle actuator 5 and the brake actuator 11 described above are connected to the output side.

Next, the tracking control executed by the ECU 14 of the tracking control device configured as described above, particularly the radio wave radar 1
A processing procedure for determining the position of the preceding vehicle based on the detection information of will be described. First, the outline of tracking control will be described.
When the tracking control set switch 16 is set by the driver, the ECU 14 emits a millimeter wave forward and receives the reflected wave reflected by the preceding vehicle, and the reflection level corresponding to the required time and the reception angle at that time is received. Based on the distribution, the coordinates (X, Y) of the preceding vehicle with respect to the own vehicle are determined as described later.
Note that X is the coordinate of the radio wave emission direction with respect to the own vehicle, and Y is X.
The coordinates are in the direction orthogonal to the coordinates. When the preceding vehicle is on the vehicle lane identified by the CCD camera 2, it is determined as a tracking target, and the wheel speed Vs of the wheel speed sensor 18 is determined.
The vehicle is accelerated or decelerated by the throttle control by the throttle actuator 5 and the brake control by the brake actuator 11 based on the obtained information such as the vehicle speed V, and the predetermined inter-vehicle distance is maintained with respect to the preceding vehicle.

The coordinates (X, Y) of the preceding vehicle used for the above tracking control are obtained by the procedure described in detail below. The detection information of the preceding vehicle by the radio wave radar 1 is obtained as the coordinates (x, y), and the final coordinates (X, y) are obtained by performing the filtering process to suppress the variable elements as described in the related art.
Y) is obtained, but the present embodiment is characterized by the Y coordinate determination processing, and the reliability of the value yt in the y coordinate direction is determined based on the estimated vehicle width W of the preceding vehicle, and according to the determination result. Then, different filter processing is applied to obtain the Y coordinate.

Therefore, first, the process of estimating the vehicle width W of the preceding vehicle will be described. The ECU 14 executes the vehicle width estimation routine shown in FIG. 2 at a predetermined control interval, and first, in step S
In step 2, it is determined based on the detection information of the radio wave radar 1 whether or not there is a preceding vehicle on the vehicle lane. If there is no preceding vehicle and the determination is NO (negative), step S4
The initial value W0 set in advance is set as the vehicle width W.
The initial value W0 is set to a minimum value of the vehicle width W that is common sense, that is, a value smaller than that of a light vehicle.

If there is a preceding vehicle, step S2
If the answer is YES in step S, step S
Move to 6 and coordinate (x, y) of the preceding vehicle based on your vehicle
To calculate. That is, as the detection information of the radio wave radar 1, the time required from the emission of the millimeter wave to the reception and the distribution of the reflection level according to the reception angle are obtained, and the distance Rt to the preceding vehicle is obtained based on the time required. The distribution angle at which the intensity of the reflection level is maximum is regarded as the angle At at which the preceding vehicle is located. These distances Rt and angles At and the coordinates (x,
Since y) has the relationship shown in FIG. 4, the coordinates (x, y) can be obtained according to the following equation (1).

(X, y) = (Rt × cosAt, Rt × sinAt) (1) Next, in step S8, the current value yt and the previous value yt- regarding the y coordinate are calculated according to the following equation (2). Find the difference Δyt from 1. Δyt = yt−yt-1 (2) Here, as is apparent from FIG. 4, it is the y coordinate value yt that correlates with the vehicle width W, but as described below, the vehicle width W
As a premise for determining, the value yt is always assumed to be located within the vehicle width W of the preceding vehicle. That is, since the radio wave from the radio wave radar 1 is reflected and received by the rear part of the vehicle, the reflection part cannot be specified, but the value yt should be located within the vehicle width, and the frequency thereof is extremely high. In other words, the value yt is constantly calculated within the vehicle width W while changing the position each time the routine is executed. And the value yt
The difference .DELTA.yt between various values is calculated according to the fluctuation of .DELTA.yt, but statistically there is a difference .DELTA.yt when the value yt greatly changes from one end to the other end within the vehicle width W. That is, a difference Δyt of a value substantially corresponding to the actual width of the preceding vehicle is obtained.

The ECU 14 determines in step S10 whether the difference Δyt is less than a preset upper limit value Wmax. The upper limit value Wmax is set as the maximum value of the vehicle width W that can be common sense, and when the difference Δyt is equal to or more than the upper limit value Wmax, it is considered that the detection information of the radio wave radar 1 this time is unreliable. The judgment is made and the routine is finished as it is. Further, when the difference Δyt is less than the upper limit value Wmax, a YES determination is made, the process proceeds to step S12, and the difference Δyt
It is determined whether t is greater than the currently set vehicle width W. When the difference Δyt is equal to or smaller than the current vehicle width W, the routine is ended as it is. When the difference Δyt is larger than the current vehicle width W, the vehicle width W is changed to a new difference Δyt in step S14.
After updating to, the routine ends.

As described above, the vehicle width W is sequentially updated in the increasing direction so as to gradually approach the vehicle width of the actual preceding vehicle based on the value yt in the y coordinate direction, and finally becomes the actual vehicle width. It is set to a value that approximates it. When the preceding vehicle does not exist due to a lane change or the like, the vehicle width W is once reset to the initial value W0 in step S4, and when a new preceding vehicle is determined, the updating of the vehicle width W is started again. . In the present embodiment, the ECU 14 at the time of executing this vehicle width estimation routine functions as a width estimation means.

On the other hand, the ECU 14 executes the Y-coordinate calculation routine shown in FIG. 3 at a predetermined control interval. First, in step S22, the coordinates of the preceding vehicle are calculated based on the detection information of the radio wave radar 1 as in step S4. x, y) is calculated. Next, in step S24, an average value yave of the preset y-coordinate direction values yt up to m times before is calculated, and in step S26, the y-coordinate direction value yt calculated in step S22 is within the vehicle width W range. Whether it is located inside,
It is determined according to the following equations (3) and (4).

Yt> yave− (W / 2) (3) yt <yave + (W / 2) (4) When both of the expressions (3) and (4) are satisfied, This means that the value yt in the y coordinate direction is located within the range of the vehicle width W. That is, as described above, the value yt should be positioned very often within the vehicle width W, and when the law is satisfied, it can be considered that the value yt of this time is highly reliable.
A determination of YES is made in step S26 and step S28
Move to. Then, in step S28, the average value of the values yt in the y coordinate direction up to m times before is set as the final Y coordinate according to the following equation (5). In this case, the past data up to m times before is used like the average value yave in step S24, but the number may be different.

Y = (yt + yt-1 + yt-2 + yt-3 ... yt- (m-1)) / m .... (5) If YES is determined in step S26, the own vehicle and the preceding vehicle It is possible to infer that the current value yt and the past data have a high relevance because of the steady relationship between and.
Therefore, in this case, the Y coordinate is stabilized by performing a filtering process using a relatively large amount of past data (up to m times before) so that the influence degree of the past data becomes large.

When the expressions (3) and (4) are not satisfied, that is, when the value yt in the y-coordinate direction is not within the range of the vehicle width W, the reliability of the value yt can be regarded as low. Yes, step S26 makes a NO determination and step S3
Move to 0. Then, in step S30, the average value of the values yt in the y coordinate direction up to n (<m) times before is set as the final Y coordinate according to the following equation (6).

Y = (yt + yt-1 + yt-2 + yt-3 ... yt- (n-1)) / n (6) If NO is determined in step S26, the host vehicle and the preceding vehicle It is possible to infer that the relation between the current value yt and the past data is low due to the transitional relations (for example, a sudden lane change of the preceding vehicle). Therefore, in this case, a relatively small amount of past data (up to n times before) is used for filtering so that the degree of influence of the past data is small, and the responsiveness of the Y coordinate is improved. .

In the present embodiment, the ECU 14 at the time of executing the process of step S22 functions as a coordinate determining means, and the ECU 14 at the time of executing the process of step S26.
Functions as the reliability determination means, and the ECU 14 when executing the processing of steps S28 and S30 functions as the filter processing means. As described above, in the tracking control device of the present embodiment, focusing on the fact that the value yt in the y-coordinate direction is located within the range of the vehicle width W of the preceding vehicle is high, and whether the condition is satisfied or not is determined. The reliability of the value yt is determined accordingly. Then, when the reliability is high, the filter processing is performed so that the influence degree of the past data becomes large, and the detection accuracy is improved by stabilizing the Y coordinate. On the contrary, when the reliability is low, the past data It is possible to improve the response of the Y coordinate by performing filtering so that the degree of influence is small, and thus to achieve both high detection accuracy and high responsiveness.

Moreover, since only software measures relating to the contents of the filter processing are implemented in this way, hardware measures such as converging the beam of the radio wave radar 1 and increasing the number of beams are used. Compared with the above, it is possible to suppress an increase in manufacturing cost to a minimum. Although the description of the embodiment has been completed, the embodiment of the present invention is not limited to this embodiment. For example, in the above embodiment, the tracking control device that accelerates and decelerates the own vehicle based on the coordinates (X, Y) of the preceding vehicle and maintains an appropriate inter-vehicle distance is used, but the inter-vehicle distance is not always automatically calculated. There is no need to control, and the adjustment of the inter-vehicle distance may be entrusted to the driver's accelerator operation, and may be embodied as a device that only warns the driver by voice when the inter-vehicle distance becomes insufficient. Further, as long as the position of the object needs to be detected, the device is not limited to the above-mentioned vehicle, and may be embodied as a device for detecting the work position on an industrial manufacturing line or the like.

On the other hand, in the above embodiment, the vehicle width W is estimated by paying attention to the fact that the value yt of the Y coordinate fluctuates within the vehicle width of the preceding vehicle, but the present invention is not limited to this and, for example, CC
The vehicle width W may be estimated based on the image information of the preceding vehicle detected by the D camera 2.

[0026]

As described above, according to the object position detecting apparatus of the present invention, the Y coordinate of the Y coordinate is detected based on whether the Y coordinate detected by the radar means is located within the range of the width of the object. Since the reliability is determined and the influence degree of the past data at the time of filtering the Y coordinate is changed according to the reliability, the influence degree of the past data becomes large when the reliability is high. Filtering is performed to stabilize the Y coordinate and improve detection accuracy. Conversely, if reliability is low, filtering is performed so that the influence of past data is small, and the responsiveness of the Y coordinate is reduced. Therefore, it is possible to achieve both higher detection accuracy and higher responsiveness.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a tracking control device of an embodiment.

FIG. 2 is a flowchart showing a vehicle width estimation routine executed by an ECU.

FIG. 3 is a flowchart showing a Y coordinate calculation routine executed by the ECU.

FIG. 4 is an explanatory diagram showing a relationship between detection information of a radio wave radar and coordinates of a preceding vehicle.

[Explanation of symbols]

1 Radio wave radar (radar means) 14 ECU (coordinate determination means, width estimation means, reliability determination means, filter processing means)

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-9-222477 (JP, A) JP-A-10-39014 (JP, A) JP-A-3-111785 (JP, A) JP-A-5- 180933 (JP, A) JP 7-209410 (JP, A) JP 9-159758 (JP, A) JP 5-273341 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01S ^7/ 00-7/42 G01S 13/00-13/95

Claims (3)

(57) [Claims] 1. A radar means for emitting an electric wave and receiving a reflected wave to detect an object, and an X-coordinate of the object substantially orthogonal to the radio wave emission direction, and orthogonal to the X-coordinate, based on the detection information of the radar means. Coordinate determining means for determining the Y coordinate, width estimating means for estimating the width of the object in the Y coordinate direction, and Y coordinate determined by the coordinate determining means for the object estimated by the width estimating means. Of the past data regarding the Y coordinate according to the reliability determined by the reliability determining means. An object position detecting apparatus, comprising: a filter processing unit that changes the degree of influence and executes Y-axis filter processing. 2. The filter processing means determines the coordinates.
The Y coordinate of the object determined by the means is the width estimation hand.
Within the width range of the object in the Y coordinate direction estimated by the step
When not located in the
Characterized by performing a filtering process so that
Item 1. The object position detection device according to item 1. 3. An object is emitted by emitting radio waves and receiving reflected waves.
A radar unit for detecting, based on detection information of the radar unit, the radio wave direction
Set the X coordinate of the object that is almost along, and the Y coordinate that is orthogonal to the X coordinate.
The coordinate determining means for determining, the current value of the Y coordinate determined by the coordinate determining means, and the previous value
Calculate the difference from the value and update the calculated difference in the increasing direction.
Width estimating means for estimating the width of the object in the Y coordinate direction
And the Y coordinate determined by the coordinate determining means is the width estimation.
Whether it is located within the width of the object estimated by the method
Reliability determination means for determining the reliability of the Y coordinate based on
According to the reliability determined by the reliability determining means.
Change the degree of influence of the past data related to
Further comprising a filter processing means for performing a filter process
An object position detecting device characterized by.