JP3498406B2 - Car driving control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is mounted on an automobile to measure the distance to a preceding vehicle or an obstacle existing in the traveling direction of the own vehicle, and to detect a front object existing in the traveling direction of the own vehicle (for example, The present invention relates to a traveling control device for an automobile that causes the subject vehicle to travel following a preceding vehicle.

[0002]

2. Description of the Related Art As a traveling control device for an automobile of this type,
For example, a scanning radar device that transmits a radar wave in front of the vehicle and receives and detects a reflected wave from an object existing in front of the host vehicle to calculate the presence or absence of a preceding object such as a preceding vehicle or an obstacle and the distance from the left and right Scanning is performed for each predetermined scanning width in a relatively wide angle in the horizontal direction, and from the received information obtained by the scanning, a microcomputer is used to determine the running state such as the steering angle and yaw rate of the vehicle. Based on the estimation, only those in the area along the traveling path of the own vehicle are picked up to calculate the distance to the preceding object by software (for example, Kaihei 1-213359
(See Japanese Patent Publication No. 3).

[0003]

By the way, in the case where the scanning radar device receives the reflected wave from the front object at each predetermined scanning width to calculate the distance to the front object as described above, On the traveling path of the own vehicle within the range of the left and right scanning angles of the radar wave,
When multiple objects exist at different distances, multiple reflected waves are received, so it is necessary to identify the specific reflected wave group (for example, from the reflector) for the target object among them. become. Further, when it is possible to identify the specific reflected wave group, since a plurality of reflected waves in the reflected wave group has different input intensity (peak level below the threshold value) depending on how the radar wave hits, There is a problem that the accuracy (distance) of the calculated data varies depending on which reflected wave is used to calculate the distance.

Further, the receiving sensitivity of the reflected wave is the AGC circuit.
The gain is controlled by the (automatic gain control circuit), and the gain is controlled at full gain when the reflected wave reception intensity is below a specified value, but when the intensity exceeds the specified value, stable reception below a specified level is achieved. It will be controlled by the gain. Therefore, it is necessary to consider those circumstances.

The present invention has been made based on the above circumstances, and detects the reflected waves from the front object as one group, and at the same time, the reception gain control level of the reflected wave group is detected.
To provide a traveling control device for an automobile which obtains stable and accurate distance data and enables accurate follow-up travel by calculating the distance to a front object using a stable reflected wave of Bell. The purpose is.

[0006]

In order to achieve the object, the present invention comprises the following problem solving means.

That is, the traveling control apparatus for an automobile according to the present invention transmits a radar wave to an object in the left and right scanning angle range in front of the vehicle with a predetermined scanning width, and outputs a reflected wave with a predetermined scanning width for each of the scanning widths . a radar unit having a reception gain control function of receiving detected in reception gain, and the reflected wave identification unit that identifies as one group a plurality of reflected waves for each scanning width from the forward object, by the reflected wave identification unit 1 A plurality of reflected waves identified as one group, and a distance calculation means for calculating a distance to the front object using a reflected wave having a stable reception gain control level among the plurality of reflected waves. .

Further, the traveling control device for an automobile of the present invention is provided with follow-up traveling control means for causing the subject vehicle to follow the distance-calculated front object in the above-mentioned structure ,
The follow-up running control means is configured to perform follow-up running control based on correlation data of both the calculated distance and the relative speed of the front object.

Further, in the vehicle traveling control device of the present invention, in the above-mentioned configuration , the radar means is constituted by a laser radar device.

[0010]

The present invention has the following actions corresponding to each of the above configurations.

That is, as described above, in the configuration of the vehicle traveling control device of the present invention, the radar wave is transmitted to the object in the left and right scanning angle range in front of the host vehicle at every predetermined scanning width, and the reflected wave is transmitted as described above. Specified for each scanning width
Receiver gain control for receiving detected by the reception gain
Functioning radar means, reflected wave identification means for identifying a plurality of reflected waves for each scanning width from the front object as one group, and the plurality of reflected wave identified as one group by the reflected wave identification means. Received gain control of reflected wave
A distance calculation means for calculating a distance to the front object using a reflected wave having a stable reflection level, and a predetermined left and right scanning angle of a plurality of reflected waves identified as one group by the reflected wave identification means. Receive gain control in range
The distance to the front object is calculated using the reflected wave with a stable roll level .

A plurality of reflected waves showing a distribution state collected as one group are reflected waves from, for example, a reflector of a specific target object, and can be specified almost accurately. And, of each of those reflected waves, the reception gain control level
A stable wave is recognized as a reflected wave having a high received light intensity of a reflected wave from a reflector or the like of a target front object and a minimum distance error .

Therefore, if the distance to the front object is calculated based on the reflected wave, accurate distance data can be obtained.

Further, in the configuration of the vehicle travel control device of the present invention, in the above configuration , the following travel control means for causing the host vehicle to follow the object whose distance has been calculated is provided. The follow-up traveling control is performed based on the correlation data of both the accurate calculated distance and the relative speed of the front object.

Therefore, based on the accurate distance calculation value and the relative speed as described above, it is possible to realize the follow-up traveling control with higher safety while maintaining an appropriate inter-vehicle distance.

Further, in the configuration of the vehicle travel control device of the present invention, in the above configuration , the radar means is composed of a laser radar device, is as thin as possible, and is affected by ambient light. Instead, the reflected wave is detected accurately and with high precision. Therefore, the accuracy of distance data calculation is high, and more reliable follow-up control is possible.

[0017]

As a result of the above, according to the vehicle travel control device of the present invention, it is possible to calculate stable distance data from the object ahead of the host vehicle, and thus to provide an accurate and safe follow-up travel control system and the like. Is possible.

[0018]

( Reference Example ) First, FIG. 3 shows an overall configuration of a vehicle traveling control device having a following traveling function according to a reference example of the present invention. Here, reference numeral 1 is a throttle valve of the engine intake system.
A throttle control device that automatically adjusts the opening (not shown),
Reference numeral 2 is a control device for an electronically controlled automatic transmission (EAT), 3 is a brake control device that automatically adjusts the braking force applied to each wheel, and these three types of control devices 1 to 3 are all not shown. Each of the actuators has an actuator, and each actuator is controlled by a traveling control unit 4 including a microcomputer.

That is, the traveling control unit 4 is
A target throttle opening signal is output to the throttle actuator of the throttle control device 1 to perform opening / closing valve control, and a target brake amount signal is output to the brake actuator of the brake control device 3 to perform braking force control. Further, the traveling control unit 4 receives a shift range position detection signal from a sensor (not shown) that detects the shift range position of the EAT control device 2, and sends a shift control signal to the shift actuator of the EAT control device 2. Is output to perform torque converter control.

The information display device indicated by reference numeral 5 is provided, for example, in an instrument panel section in the vehicle compartment, and an alarm lamp (not shown) which is turned on upon receiving a vehicle distance alarm signal from the traveling control unit 4. , A display unit for receiving a system self-diagnosis signal from the traveling control unit 4 and displaying it on the screen.

On the other hand, the laser radar device shown by reference numeral 6 acts as a front object detecting means for detecting an object (for example, a preceding vehicle) existing in front of the own vehicle, and the laser radar wave is in front of the own vehicle. It is configured to send to the vehicle, receive the reflected wave that hits the front object and is reflected, and measures the distance (vehicle distance, etc.) between the vehicle and the front object by the time difference between the reception time and the transmission time. Has been done. The detection signal detected by the laser radar device 6 is input to the traveling control unit 4 as an inter-vehicle distance signal. The laser radar device 6 of this reference example is shown in FIG.
As shown in FIG. 7, a laser radar head 16 is provided, and as shown in FIG. 7, a beam type laser radar wave is horizontally emitted to the left and right at predetermined scanning widths to to tn and is scanned within a predetermined angle θ. It is supposed to be (see below).

Reference numeral 7 is a throttle opening sensor for detecting the opening of the throttle valve, 8 is a vehicle speed sensor for detecting the vehicle speed, 9 is a steering angle sensor for detecting the steering angle of the steering wheel (hereinafter, simply referred to as steering angle), and 10 is A yaw rate sensor that detects the yaw rate that occurs in the vehicle, 11 is a lateral G sensor that detects the lateral acceleration that occurs in the vehicle, 12 is a brake switch that is turned on when the brake pedal is depressed, and 13 is in accordance with the operating state of the clutch. The clutch switch that is turned on, 14 is a lock-on switch that catches the target vehicle during follow-up running, and 15 is an auto cruise switch that is turned on when the own vehicle is in cruising operation. All detection signals are input to the traveling control unit 4. Although detection signals of an engine speed sensor (not shown) and other sensors and switches are also input to the traveling control unit 4, detailed description thereof will be omitted.

By the way, as shown in FIG. 4, the laser radar device 6 is roughly divided into three parts: a laser radar head 16, a time measuring unit 20, and a signal processing unit 30.

In the laser radar head 16, a light emitting lens (condensing lens) 24 is arranged in front of one light emitting element 17 composed of an LD (laser diode).
A light-receiving lens (condenser lens) having a lattice-shaped mechanical filter 27 on the front side of each of the light-receiving elements 18 and 19
25 and 26 are arranged. Reference numeral 28 is a drive circuit (light emitting portion) of the LD, and 29 is a light receiving circuit (light receiving portion).

The one light emitting element 17 and the first and second light receiving elements 18 and 19 are arranged on the turntable 3 as shown in FIG.
Lenses 24, 25, 26 which are placed on 7 and belong to them
And the mechanical filters 27, 27 also include the turntable 3
It is mounted on 7. As understood from FIG. 5, the light emitting element 17 and the lens 24 thereof are drawn on one side of the laser radar head 16 for convenience in FIG. 4, but in reality, as shown in FIG. 5, the first and second light receiving elements 18 are provided. , 19 and its lenses 25, 26.

The time measuring unit 20 includes a pulse generator 21 for generating a start pulse for the drive circuit of the LD, and a time measuring for starting the time measurement by the start pulse and ending the time measurement by the start pulse from the light receiving circuit 29. It has a section 22 and a power supply section 23, respectively. The signal processing unit 30 also includes a distance measuring unit 31 that calculates a distance based on the time data obtained by the time measuring unit 22 and a display unit 32 that displays the result.

Further, the laser radar head 16 rotates the turntable 37 to receive the light receiving areas 43 and 44 of the first and second light receiving elements 18 and 19 and the light emitting element 17.
5 is provided with a servo mechanism 34 for deflecting a light emitting area (not shown) of FIG. 5 and a drive motor 35 thereof. The current rotation angle of the servo mechanism 34 is detected by a potentiometer 36 that works in conjunction with the drive motor 35.

The signal processing unit 30 always captures the reflector 40 of the preceding vehicle in the overlapping area of the light receiving areas 43 and 44 of the first and second light receiving elements 18 and 19 as shown in FIG. Further, as a control means for rotating the turntable 37, a servo control unit 33 for giving an appropriate command to the drive motor 35 of the servo mechanism 34 is provided. More specifically, the servo control unit 33 tells the servo mechanism 34 from the combination of the magnitude relationships of the measured values of the first and second light receiving elements 18 and 19 measured by the distance measuring unit 31 that It is designed to give a command as to whether or not the drive motor 35 is rotating and a rotation direction.

Now, for example, in FIG. 5, a start pulse is output from the pulse generator 21 of the time measuring unit 20 to the LD drive circuit 28 of the laser radar head 16. Then, the LD drive circuit 28 drives the LD, which is the light emitting element 17, by the trigger of the start pulse, and the laser pulse is received by one or both of the first and second light receiving elements 18 and 19 and has a predetermined output current. After being generated and amplified by the light receiving circuit 29, a stop pulse is applied to the time measuring unit 2
Output to 2. The time measuring unit 22 measures the time interval between the start pulse from the pulse generating unit 21 and the stop pulse from the light receiving circuit 29, and outputs it as time data to the distance measuring unit 31. The distance measuring unit 31 calculates (converts) the distance to the preceding vehicle from the time data and outputs it as distance data to the traveling control unit 4 of the vehicle.

Here, the first and second light receiving elements 18,
When 19 does not receive the reflected light, the distance measurement value at the corresponding light receiving element coefficient in the distance measurement unit 31 becomes “maximum”, and the distance data is treated as a signal indicating that there is no preceding vehicle. However, when there is some distance measurement value, it is determined that "there is a preceding vehicle", and it is treated as a signal to that effect.

By the way, the radar wave from the light emitting element 17 of the laser radar device 6 is formed into a beam as thin as possible,
For example, within a range of the left and right scanning angles θ shown in FIGS. 7 and 8, a predetermined number of times to to tn are time-divided and a predetermined scanning width to to tn is repeatedly scanned at a predetermined cycle T to transmit and receive. There is.

As will be described later, a radar wave having a predetermined scanning width to to tn hits a reflector (reflector) 40 at the rear of the vehicle traveling in front of the vehicle, for example, and a plurality of reflected wave groups from left to right. Group data (distance)
Is calculated (see FIG. 10).

Further, when receiving the reflected wave, the light receiving circuit 29 is provided with an AGC control function (automatic gain control function) of the receiving sensitivity according to the received light intensity, and the predetermined value from the reflector 40 is provided. When there is no reflected wave input above the threshold level, the reception sensitivity is controlled with full gain (MAX gain), but when there is a reflected wave input from the reflector 40 above the above predetermined threshold level, below the predetermined sensitivity The receiver sensitivity is controlled at a stable gain level (see FIG. 13).

Then, the traveling control unit 4
Is an input information processing unit that receives a detection signal from various sensors and switches 7 to 15 including a distance data signal from the laser radar device 6 and performs predetermined information processing, and an input information processing unit A traveling path that receives information (for example, the vehicle speed from the vehicle speed sensor 8, the steering angle from the steering angle sensor 9 and the yaw rate from the yaw rate sensor 10) related to the traveling state of the vehicle, and estimates the traveling path of the vehicle based on these Of the information of the estimation means and the input information processing unit,
In particular, a lock that receives detection data on a front object detected by the laser radar device 6 and determines whether the object exists on the traveling path with a predetermined movement condition, and determines this as a preceding vehicle to be followed by the own vehicle. An on-determination means is provided.

The information on the preceding vehicle determined to be the tracking target object by the lock-on determination means is output from the lock-on determination means to the tracking control means. The follow-up control means, via the output information processing unit, controls the vehicle speed of the own vehicle so that the own vehicle follows the preceding vehicle on the basis of the inter-vehicle distance and the relative speed between the own vehicle and the preceding vehicle to be followed. Output the output signal.

Furthermore, the distance measuring unit 31 of the signal processing unit 30 of the laser radar device 6 continuously outputs a distance or time data group corresponding to one reflected wave group from the object ahead of the time measuring unit 20. Forward using the reflected wave identification means for identifying as a data group and the reflected wave data (distance or time data) at a predetermined left / right scanning angle Δθ direction intermediate position among the plurality of reflected wave group data identified by the reflected wave identification means And a distance calculation means for calculating the distance to the object.

Hereinafter, the group data detection control and distance (time) data selection (calculation) for front object detection by the signal processing unit 30 and the traveling control unit 4 will be described.
The details of control will be described in detail.

<Basic Control for Selecting Distance Data> FIG. 9 shows a main routine of the distance detection control from the front object.

In the control, first, in steps S1 and S2, the laser radar device is turned on to have a predetermined scanning angle θ and a predetermined scanning width in a predetermined scanning direction.
The scanning from to to tn is started, and the laser radar wave is transmitted to the front of the vehicle (see FIGS. 7 and 8).

Next, in step S3, after receiving and inputting a reflected wave for each predetermined scanning width to to tn of the laser radar wave transmitted with the predetermined scanning width to to tn, in step S4, for example, forward from the received signal. One independent group data (distance-equivalent data) among the plurality of reflected waves seen from the reflector 40 of the vehicle traveling on the road is detected (FIG. 1).
0).

Thereafter, any distance data is further selected from the group data in step S5, and it is determined in step S6 whether or not one scanning cycle T of FIG. 8 is completed. The process returns to step S1 to execute the same processing as described above in the next cycle T, and repeats thereafter.

<Group data detection, distance data selection control> Next, FIG. 11 shows group data detection control of a plurality of reflected waves in steps S4 and S5 of the main routine shown in FIG. 9 and distance data from the group data. 3 shows a selection control subroutine.

That is, first, in step S1, various data such as the presence / absence of the reflected wave reception input of the laser radar device 6 is read.

Then, in step S2, it is determined whether or not the reflected wave is actually received.

As a result, if YES, the process proceeds to step S3, and it is determined whether or not the reflected wave was received last time. If the result of this determination is that there was no reflected wave received the previous time, but the first time that the reflected wave was received this time for the first time, the operation proceeds to step S4, and the continuous group data for detecting the independent group data is detected. First, the count value of the data counter CK is set to "1" and the first distance data D1 is stored. On the other hand, if the previous reception was received, the process proceeds to step S5, and the count value of the continuous data counter CK is incremented by one (N
+1) to store the distance data Dn + 1.

On the other hand, when the reflected wave is received this time which is determined as NO in the determination in step S2, step S2 is performed.
Proceed to step 6 to determine whether or not the reflected wave was received last time.

As a result, if YES, the process proceeds to step S7, and after confirming the continuous data number N (the number of D1 to Dn) of the continuous data counter CK stored until then, in step S8, for example. It is determined whether or not the value of the continuous data number N is equal to or more than a predetermined set value (minimum value for taking the value of the intermediate angle). As a result of the judgment, YES
If so, the process proceeds to step S9, and the first to the Nth
The N / 2th data (intermediate angle value of a plurality of reflected wave inputs) of the continuous data up to the second is set as selection data (distance calculation data). On the other hand, if NO, the process proceeds to step S10,
Among the continuous data D1 to Dn (however, in this example, n is 2 or less), the data D1 or D2 having the shorter distance is used as the selection data.

On the other hand, when the reflected wave is not received in the previous time and this time when the result of the determination in step S6 is NO,
Admitting that there is no front vehicle ahead of your vehicle, proceed to step S11,
The count value N of the continuous data counter CK is all cleared and the process returns to step S1.

After that, the group data is detected and the distance data is selected by repeating the above operation.

As described above, the plurality of reflected waves showing the distribution state collected as one group are the reflected waves from, for example, the reflector of a specific target object such as a preceding vehicle, and can be specified almost accurately. Among the reflected waves, the one at a predetermined intermediate position of the right and left scanning angles is recognized as an appropriate reflected wave having the highest received light intensity from the central portion such as the reflector of the target specific front object.

Therefore, if the distance to the front object is calculated based on the reflected wave, accurate distance data can be obtained.

( Embodiment 1 ) Next, FIGS. 12 and 13 show a plurality of flowcharts of FIG. 9 according to Embodiment 1 of the present invention in which the reception gain of the AGC circuit in the light receiving circuit 29 of FIG. 4 is used as a parameter. The contents of the group data detection control and the distance data selection control of the reflected waves are shown.

That is, first, in step S1, various data such as the presence / absence of the reflected wave reception input of the laser radar device 6 is read.

Then, in step S2, it is determined whether or not the reflected wave is actually received.

As a result, if YES, the process proceeds to step S3, and it is determined whether or not the reflected wave was received last time. If the result of this determination is that there was no reflected wave received the previous time, but the first time that the reflected wave was received this time for the first time, the operation proceeds to step S4, and the distance data memory DM is set to 1
D1 is stored as the distance data for the first time. On the other hand, if YES in the previous reception, the process proceeds to step S5, where the AGC gain level of the received signal is the same as that of the previous time.
It is determined whether or not it is the C gain level. As a result, N
When the AGC gain level of O changes, the process proceeds to step S6 to store the data of the closer distance as temporary data, and when YES, the data Dn is sequentially stored in the distance data memory DM. As a result, group data corresponding to distances corresponding to a plurality of reflected wave groups is formed.

On the other hand, if the reflected wave determined as NO in the above step S2 is not received, step S8
The process proceeds to step S13 to control the selection of the distance in the distance data group of the distance data memory DM.

That is, first, in step S8, it is determined whether or not the group data is stored by the group data detection control. As a result, when the group data of NO is not stored,
In step S9, it is determined whether the temporary data stored in step S6 is stored.

As a result, if NO, the routine proceeds to step S10, where it is judged whether or not the data of the first time of the above step S4 is stored. If YES, it proceeds to step S11 and the first time of the first time. The data is input to the distance data memory DM.

On the other hand, if the result of the determination in step S9 as to whether or not the temporary data is stored is YES, the process proceeds to step S12, and the average value thereof is calculated and selected as distance data.

On the other hand, if the group data determined to be YES in the step S8 is stored, the process proceeds to step S13 to calculate the average value of each stable group data of the AGC gains and to detect the front object. Select distance data (calculation)
(See FIG. 13). The distance data group where the AGC gain is stable is not the full gain, but is the appropriate data based on the reflected wave that is appropriately reflected by the reflector 40 of the front vehicle and returns, and it is more appropriate to average them. It is possible to calculate various distances.

Other Embodiments Regarding selection of the distance data, for example, the reflector 40
In the case where the way the radar wave hits the object is as shown in FIG. 14, as a reference example , one of the two end sides 1 of the reflector 40 in which the way of hitting the plurality of reflected waves identified as one group is not appropriate
It is also possible to calculate the average value of the group data in the intermediate angle range excluding the data of the second time and the data of the nth time and use it as the distance data.

In that case, when the time-divided scanning widths to to tn are further subdivided by a factor of about 2 as compared with FIG. 14, for example, as a reference example , a plurality of groups identified as one group are identified. Of the reflected wave group data of, the average value of the group data in the intermediate angle range excluding the first and second data and the data on both ends of the n-1 and n-2 reflectors is calculated to obtain distance data. do it.

Further, in the case of FIG. 14, for example, the terminal side data is excluded from the group data of a plurality of reflected waves identified as one group as a reference example .
It is also possible to average each of the n-5, n-4, n-3, n-2, and n-1 times data to obtain distance data.

[Brief description of drawings]

FIG. 1 is a reference diagram of the present invention.

FIG. 2 is a diagram corresponding to claims of the present invention (claim 1,
2, 3).

FIG. 3 is an overall system diagram of a vehicle travel control device according to a reference example of the present invention.

FIG. 4 is a system diagram of a laser radar device section of the device.

FIG. 5 is a plan view of a laser radar head portion of the same laser radar device in a first state.

FIG. 6 is a plan view of a laser radar head section of the same laser radar device in a second state.

FIG. 7 is an explanatory diagram showing a transmission and reception state of a radar wave from the laser radar head to a reflector.

FIG. 8 is a time chart showing a radar wave scanning operation of the laser radar head unit.

FIG. 9 is a flowchart showing a basic control routine of a traveling control device including the laser radar device section.

FIG. 10 is a data table showing an example of group data detection of the control device.

FIG. 11 is a flowchart showing the contents of group data detection and distance data selection control of the control device.

FIG. 12 is a flowchart showing the contents of group data detection and distance data selection control of the vehicle travel control device according to the first embodiment of the present invention.

FIG. 13 is a time chart showing a distance data selection control operation of the control device.

FIG. 14 is an explanatory diagram showing a radar wave transmission / reception state of a laser radar head portion of a vehicle travel control device according to another embodiment of the present invention.

[Explanation of symbols]

4 is a traveling control unit, 6 is a laser radar device, 17 is a light emitting element, 18 is a first light receiving element, 19 is a second light receiving element, 20 is a time measuring unit, 28 is an LD drive circuit, 29 is a light receiving circuit, 30 is a signal processing unit, 3
1 is a distance measuring unit.

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01S ⁷ /00-17/88 B60R 21/00 621 G08G 1/16

Claims (3)

(57) [Claims] 1. A radar wave is transmitted to an object in the left and right scanning angle range in front of the own vehicle for each predetermined scanning width,
Radar means having a reception gain control function for receiving and detecting the reflected wave with a predetermined reception gain for each scanning width, and a reflected wave for identifying a plurality of reflected waves from the preceding object for each scanning width as one group Identification means, and distance calculation means for calculating a distance to the front object by using a reflected wave having a stable reception gain control level among the plurality of reflected waves identified as one group by the reflected wave identifying means. A traveling control device for an automobile, comprising: 2. When the front object is a moving object, a follow-up running control means is provided for causing the subject vehicle to run following the front object whose distance has been calculated. The vehicle running control device according to claim 1, wherein the following running control is performed based on the correlation data of both the relative speed with respect to the object. 3. The vehicle traveling control device according to claim 1 , wherein the radar means is a laser radar device.