JP2005043247A - Preceding vehicle detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a preceding vehicle detection device capable of detecting accurately preceding vehicles on both front sides of one's own vehicle. <P>SOLUTION: When determined that the preceding vehicle is performing a lane change movement, the elevation angle including the height of a reflector of the detected preceding vehicle is set as an elevation angle when scanning the right and left sides next time in a prescribed range in the right and left directions including the preceding vehicle, and a prescribed elevation angle is set as an elevation angle when scanning the right and left sides next time in a range not including the preceding vehicle. Hereby, for example, even when another preceding vehicle exists on a farther position than the preceding vehicle performing the lane change movement on a running route where own vehicle is running, right and left scanning can be performed at the prescribed elevation angle from own vehicle in the range not including the near preceding vehicle, to thereby discover accurately another preceding vehicle. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a preceding vehicle detection apparatus that scans a laser beam to detect a preceding vehicle.

Conventionally, laser light is scanned to the left and right in front of the host vehicle at a predetermined elevation angle, the reflected light reflected by the preceding vehicle is received, and the preceding vehicle and the host vehicle are determined according to the time from the emission of the laser beam to the reception of the reflected light. A preceding vehicle detection device that detects a distance, a relative speed, and the like is known (for example, Japanese Patent Application Laid-Open No. 2003-57339, Japanese Patent Application Laid-Open No. 2003-121546). In such a preceding vehicle detection device, in order to ensure the intensity of reflected light from the preceding vehicle, the elevation angle and the vertical spread angle of the emitted laser light are usually determined by the laser beam on the reflector of the preceding vehicle ahead of the vehicle by a predetermined distance. Is set to the angle of irradiation.
JP 2003-57339 A JP 2003-121546 A

However, in such a conventional preceding vehicle detection device, when the distance between the preceding vehicle and the host vehicle is shorter than the predetermined distance, the laser beam may not be applied to the reflector of the preceding vehicle. As a result, the reflection intensity may decrease and the detection accuracy of the preceding vehicle may deteriorate.
In order to solve this, for example, it is conceivable to change the vertical position when scanning the laser beam to the left and right to a position including the reflector height of the preceding vehicle. However, when the preceding vehicle changes lanes, There is a problem that the laser beam is not irradiated to the reflector of another vehicle on the vehicle lane (for example, another preceding vehicle traveling ahead of the preceding vehicle), and the detection accuracy of the preceding vehicle is poor.

  Therefore, in view of such problems, the present invention has an object of providing a preceding vehicle detection device that can accurately detect a preceding vehicle ahead of the host vehicle.

  The present invention includes an emitting unit that emits laser light, a scanning unit that scans the laser beam emitted from the emitting unit in the left-right direction in front of the host vehicle, a light receiving unit that receives reflected light of the laser beam, and the light receiving unit. In a preceding vehicle detection device comprising a preceding vehicle detection means for detecting a preceding vehicle from a laser beam received by the means, reflector height detection means for detecting the height of the reflector provided at the rear of the detected preceding vehicle; Lane change operation detection means for detecting the lane change operation of the preceding vehicle or the lane change operation of the host vehicle, and the scanning means scans the laser beam in the left and right directions at a predetermined elevation angle that is predetermined as an initial value. If the preceding vehicle is detected by the vehicle detecting means, and further the lane changing operation of the preceding vehicle or the host vehicle is detected by the lane changing operation detecting means, the next scanning is performed. In addition, in a predetermined lateral range including the detected preceding vehicle, laser light is scanned in the lateral direction at an elevation angle that includes the reflector height of the preceding vehicle detected by the reflector height detecting means in the irradiation range. Except for the direction range, the laser beam was scanned in the left-right direction at a predetermined elevation angle.

  According to the present invention, when a lane change operation of the preceding vehicle or the host vehicle is detected, the preceding vehicle is scanned left and right at a predetermined elevation angle except for a predetermined lateral range including the preceding vehicle. When the lane change operation is performed, it is possible to accurately detect other preceding vehicles other than the preceding vehicle ahead of the host vehicle, and when the host vehicle performs the lane change operation, the lane change destination It is possible to accurately detect other preceding vehicles on the road.

  Next, embodiments of the present invention will be described by way of examples.

First, the first embodiment will be described.
FIG. 1 shows the mounting position of the preceding vehicle detection device, and FIG. 2 shows the overall configuration of the preceding vehicle detection device.
As shown in FIG. 1, a preceding vehicle detection device 16 that detects a vehicle in front of the host vehicle 12 is installed at the center position in the width direction of the front portion of the host vehicle 12. The preceding vehicle detection device 16 emits a laser beam toward the front of the host vehicle 12 and detects the inter-vehicle distance from the preceding vehicle based on the time until the reflected light returns.

Next, the configuration of the preceding vehicle detection device 16 will be described with reference to FIG.
The case 17 of the preceding vehicle detection device 16 is provided with a light projection window 201 and a light reception window 202 having a lens function. Inside this case 17 is a laser light emitting element (LD) 206 in the near-infrared wavelength region, and a laser light receiving element that receives the laser light that is returned from the laser light transmitted from the laser light emitting element 206 and reflected by a preceding vehicle or the like. PD) 205, a driving circuit 208 for driving the laser light emitting element 206, and an amplifying circuit 207 for amplifying a weak received light signal from the laser light receiving element 205.

  Furthermore, a reflection mirror 203 that reflects the laser beam transmitted from the laser light emitting element 206 to the front of the host vehicle is provided inside the case 17. The reflection mirror 203 rotates vertically and horizontally, and the reflection mirror 203 is rotated with a predetermined angular resolution (n × m) by a stepping motor 204 driven by a motor drive circuit 209. As a result, scanning ahead of the host vehicle is performed with n beams in a predetermined angular range in the left-right direction and m beams in a predetermined angular range in the vertical direction.

  Further, a CPU 210 that controls the amplifier circuit 207, the drive circuit 208, and the motor drive circuit 209 is provided. When the CPU 210 controls the drive circuit 208 and the amplifier circuit 207, laser light is transmitted as emitted light from the laser light emitting element 206, and reflected light is received by the laser light receiving element 205.

The CPU 210 receives as input information the steering angle detected by the steering angle sensor 11, the turn signal lamp on / off signal detected by the turn signal lamp sensor 21, the speed of the host vehicle detected by the vehicle speed sensor 22, and the like. The CPU 210 records the intensity of the received light signal received by the laser light receiving element 205 in a time-resolved manner, calculates the distance from the preceding vehicle, the detection direction, the relative speed, and the like, and from the detection result detected by the steering angle sensor. Estimate the curvature of the traveling path in the traveling direction.
The calculation result by the CPU 210 is output as output information to a display device (not shown) or to a vehicle control device.

FIG. 3 explains the relationship between the laser light irradiation range and the reflector attached to the preceding vehicle.
Here, the reflector installed behind the vehicle is mounted at a position where the height from the road surface is 250 mm or more and 1500 mm or less, for example, according to the safety standard for road transport vehicles.

The preceding vehicle detection device 16 is installed, for example, on the upper part of the front bumper of the vehicle, and the mounting angle is the optical axis of the initial value of the emitted light at a distance (for example, 100 m) where detection from the own vehicle 12 to the preceding vehicle 13 is desired. The upper limit and the lower limit of the height of the reflector 19 attached to the rear part of the preceding vehicle 13 are included in the beam of the emitted light when scanned.
Hereinafter, the elevation angle when the preceding vehicle detection device 16 scans the emitted light left and right at the initial value is referred to as a predetermined elevation angle.

Next, the flow of elevation angle setting processing performed by the CPU 210 will be described with reference to the flowchart of FIG.
In step 400, left and right scanning is performed at a predetermined elevation angle at the initial value. Alternatively, if the vertical elevation angle when scanning left and right is set in steps 405, 408, 409, and 410, which will be described later, the horizontal scanning is performed at the set elevation angle.

In step 401, it is checked whether or not a preceding vehicle has been detected at the previous scanning, and if a preceding vehicle has been detected, the process proceeds to step 402. If not, the process proceeds to step 407. . In the initial flow, since no preceding vehicle is detected, the process proceeds to step 407. In step 402, it is determined whether or not there is a reflected light from the reflector of the preceding vehicle by the current scan executed in step 400 and the preceding vehicle is detected. judge. If a preceding vehicle is detected, the process proceeds to step 403, and if not detected, the process proceeds to step 410.

In step 403, the height of the reflector of the preceding vehicle is detected.
In step 404, it is determined whether or not the preceding vehicle is performing a lane change operation from the traveling lane in which the vehicle is currently traveling.
Here, the travel route of the host vehicle 12 can be estimated from the output value of the rudder angle sensor 11 attached to the host vehicle 12. If the host vehicle 12 is traveling in the lane center of the travel lane 15, the estimated travel route can be estimated as the lane center 14 of the travel lane 15.
As shown in FIG. 5, the lane change operation is determined when the lateral deviation amount between the lane center 14 estimated from the curvature detected by the rudder angle sensor 11 and the preceding vehicle center of the preceding vehicle 13 exceeds a predetermined value. Furthermore, it is determined that the preceding vehicle 13 is performing a lane changing operation from the traveling lane 15.

In addition, as the predetermined value of the lateral deviation amount, a value that a vehicle with a standard vehicle width crosses the lane marking is set, or a value that a human judges as the preceding vehicle deviates from the driving lane experimentally. Set by asking.
The preceding vehicle center is the center position between the pair of reflectors detected by the preceding vehicle 13.

If it is determined that the preceding vehicle is performing a lane change operation, in step 405, the elevation angle for the next left / right scanning is set.
As shown in FIG. 6, the elevation angle is set in the predetermined left-right range (right side in the figure) including the preceding vehicle detected in step 402. The height of the reflector 19 of the detected preceding vehicle is determined by the emitted light. The elevation angle for the next left / right scanning is set so as to be included in the beam (laser irradiation range 18).

In addition, the range of the maximum width | variety (for example, 2.5 m) which exists as a vehicle in the left-right direction centering on the preceding vehicle center is set as a range of the predetermined left-right direction including a preceding vehicle.
On the other hand, in the range in the left-right direction that does not include the preceding vehicle (the left side in the figure), a predetermined elevation angle at the initial value is set as the elevation angle for the next horizontal scan.

  By setting the elevation angle in this way, as shown in FIG. 6, for a predetermined range including the preceding vehicle, the laser irradiation range 18 is scanned left and right at an elevation angle including the reflector height of the preceding vehicle, and the preceding light is scanned. The vertical direction of the emitted light changes at the boundary between the range including the vehicle and the range not including the vehicle, and left and right scanning is performed at a predetermined elevation angle in the range not including the preceding vehicle.

In step 406, whether or not a preceding vehicle has been detected by the scan executed in step 400, the distance to the preceding vehicle, the relative speed with respect to the preceding vehicle, and the like are output as output information.
When the preceding vehicle is not changing lanes in the check in step 404, in step 409, when the elevation angle including the reflector height of the preceding vehicle detected in step 403 in the laser irradiation range 18 is scanned left and right next time And the process proceeds to Step 406.

If it is determined in step 401 that no preceding vehicle has been detected in the previous scan, it is determined in step 407 whether a preceding vehicle has been detected by the scan executed in step 400. If a preceding vehicle has been detected, the process proceeds to step 403, and if not, the process proceeds to step 408.
In step 408, the predetermined elevation angle is set as the elevation angle for the next horizontal scan, and the process proceeds to step 406.

If the preceding vehicle is not detected in the scan in step 402, the elevation angle at which the reflector of the preceding vehicle can be captured is estimated based on the position of the preceding vehicle detected in the previous scan in step 410. The estimated elevation angle is set as the elevation angle for the next horizontal scan.
When estimating the elevation angle, for example, it is determined whether or not the vehicle has approached the preceding vehicle based on the speed of the host vehicle. Change above the previously set elevation angle.

  In this embodiment, steps 400, 405, 408, 409 and 410 constitute the scanning means in the present invention. Step 402 constitutes the preceding vehicle detection means in the present invention, and Step 403 constitutes the reflector height detection means in the present invention. Further, step 404 constitutes a lane change operation detecting means in the present invention. The laser light receiving element 205 constitutes the light receiving means in the present invention, and the laser light emitting element 206 constitutes the emitting means in the present invention.

The present embodiment is configured as described above, and when it is determined that the preceding vehicle is performing a lane change operation, the height of the detected reflector of the preceding vehicle is detected for a predetermined range including the preceding vehicle by laser irradiation. The elevation angle included in the range is set as the elevation angle when the next scanning is performed to the left and right, and the predetermined elevation angle is set as the elevation angle when performing the next horizontal scanning for the range not including the preceding vehicle.
As a result, for example, even if another preceding vehicle exists at a position farther than the preceding vehicle that is performing the lane change operation on the travel route on which the own vehicle is traveling, the preceding vehicle that is closest to the own vehicle is not included. With respect to the range in the left-right direction, scanning can be performed at a predetermined elevation angle, and other preceding vehicles can be found accurately.

Further, as shown in FIG. 7, even when the preceding vehicle 13 performs a lane change operation in a state where the height of the reflector 19 of the preceding vehicle 13 is high and the irradiation range Z of the laser beam faces upward. In the horizontal scanning range not including the preceding vehicle 13, the laser beam is irradiated at a predetermined elevation angle. The reflector 19A of the preceding vehicle 13A can be captured by the irradiation range W of the laser beam irradiated at the predetermined elevation angle.
Therefore, another preceding vehicle 13A that is farther than the preceding vehicle 13 has entered the lower part of the laser light irradiation range Z and cannot be detected, or has been reflected by a distant high-position sign 23 or the like. There is no possibility of receiving reflected light and erroneously detecting the sign 23 as a preceding vehicle.

The lane change operation is easily determined by determining that the preceding vehicle is performing the lane changing operation when the lateral deviation amount between the center in the width direction of the preceding vehicle and the center of the lane exceeds a predetermined value. be able to.
In addition, by setting the center position between a pair of reflectors having high reflection intensity and easy identification as the center of the preceding vehicle, it is possible to easily detect the center of the preceding vehicle without using other sensors.
Since the curvature of the lane is calculated from the output value of the rudder angle sensor 11, it is not necessary to provide a road map for obtaining the curvature of the lane, and the curvature of the lane can be easily obtained by calculation.

Next, a second embodiment will be described.
In this embodiment, only the processing contents performed by the CPU 210 in the first embodiment are changed. Other configurations are the same as those of the first embodiment, and a description thereof will be omitted.
The flow of elevation angle setting processing performed by the CPU 210 will be described with reference to the flowchart of FIG.
Steps 700 to 703 are the same as steps 400 to 403 in the first embodiment, and a description thereof is omitted.

In step 704, it is determined whether or not the host vehicle is performing a lane change operation.
This determination is that the lane change operation is being performed when the turn signal lamp of the host vehicle is ON and the steering angle of a predetermined value or more is in the same direction as the direction in which the turn signal lamp is operated. To do.

If it is determined that the host vehicle is performing a lane change operation, in step 705, the elevation angle for the next left / right scan is set.
As shown in FIG. 9, in the setting of the elevation angle, the predetermined elevation angle is set as the elevation angle for the next horizontal scan in the horizontal range (right side in the figure) that does not include the preceding vehicle within the scannable range.

  On the other hand, in the predetermined range in the left and right direction including the preceding vehicle detected in step 702 (left side in the figure), the height of the detected reflector 19 of the preceding vehicle is included in the beam of emitted light next time. Set the elevation angle when scanning left and right.

  By setting the elevation angle in this way, as shown in FIG. 9, the emission light is scanned left and right at a predetermined elevation angle in the range not including the preceding vehicle, and the emission light is at the boundary between the range including the preceding vehicle and the range not including the preceding vehicle. As for the predetermined range including the preceding vehicle, the emitted light is scanned left and right at an elevation angle where the laser irradiation range 18 includes the reflector height of the preceding vehicle.

In step 706, whether or not the preceding vehicle has been detected by the scan executed in step 700, the distance to the preceding vehicle, the relative speed with the preceding vehicle, and the like are output as output information.
When the vehicle is not changing lanes in the check of step 704, in step 709, the elevation angle including the reflector height of the preceding vehicle detected in step 703 in the laser irradiation range 18 is scanned left and right. Set as the elevation angle and go to step 706.

If it is determined in step 701 that a preceding vehicle has not been detected in the previous scan, it is determined in step 707 whether a preceding vehicle has been detected in the scan in step 700. If a preceding vehicle is detected, the process proceeds to step 703. If not detected, the process proceeds to step 708.
In step 708, the predetermined elevation angle is set as the elevation angle for the next horizontal scan, and the process proceeds to step 706.

  If the preceding vehicle is not detected in the scan in step 702, the elevation angle that can capture the reflector of the preceding vehicle is estimated based on the position of the preceding vehicle detected in the previous scan in step 710. The estimated elevation angle is set as the elevation angle for the next left / right scan.

  In this embodiment, steps 700, 705, 708, 709 and 710 constitute scanning means in the present invention. Step 702 constitutes the preceding vehicle detection means in the present invention, and step 703 constitutes the reflector height detection means in the present invention. Further, step 704 constitutes a lane change operation detecting means in the present invention.

The present embodiment is configured as described above, and when the host vehicle is in a lane change operation, an elevation angle that includes the detected height of the reflector of the preceding vehicle in the laser irradiation range for a predetermined range including the preceding vehicle. Next, the elevation angle is set as the elevation angle when the left and right scanning is performed next time, and the predetermined elevation angle is set as the elevation angle when the next horizontal scanning is performed for the range not including the preceding vehicle.
Thus, for example, when there is a preceding vehicle on the travel path before the lane change, and there is another preceding vehicle on the travel path before the lane change, the preceding vehicle existing on the travel path before the lane change is changed. Since the horizontal range that is not included is scanned at a predetermined elevation angle, other preceding vehicles existing at the lane change destination can be accurately found.

  In particular, when the height of the reflector of the preceding vehicle existing on the travel path before the lane change is at a high position, the laser scanning range is facing upward, but in the left-right range not including the preceding vehicle, Because the vehicle scans left and right at a predetermined elevation angle, if the vehicle performs a lane change operation, another preceding vehicle that is present on the lane change destination travels underneath the laser scanning range or a distant sign And the like are not erroneously detected.

When the direction indicated by the turn signal lamp matches the detected rudder angle direction, it is easy to determine the lane change operation of the host vehicle by determining that the host vehicle is performing the lane change operation. Can do.
In each of the above embodiments, the road curvature is calculated using the rudder angle detected by the rudder angle sensor 11, but the yaw rate sensor is attached to the host vehicle 12, and the road curvature is calculated from the detected yaw rate. You can also.
Alternatively, using the yaw rate instead of the rudder angle, it can be determined that the host vehicle is performing a lane change operation when the indicated direction of the turn signal lamp matches the yaw rate.
Further, as shown in FIGS. 6 and 9, it is preferable to set the elevation angle so that the reflector 19 can be captured at the center position in the height direction of the laser irradiation range 18.

It is a figure which shows the attachment position of a preceding vehicle detection apparatus. It is a figure which shows the structure of a preceding vehicle detection apparatus. It is a figure which shows the relationship between the irradiation range of a laser beam, and the reflector attached to the preceding vehicle. It is a figure which shows the flow of the setting process of the elevation angle which CPU performs. It is a figure which shows the lane change operation | movement of a preceding vehicle. It is a figure which shows the elevation angle at the time of scanning a laser beam right and left. It is a figure which shows the irradiation range of a laser beam. It is a figure which shows the flow of the setting process of the elevation angle which CPU performs. It is a figure which shows the elevation angle at the time of scanning a laser beam right and left.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Rudder angle sensor 12 Own vehicle 13 Leading vehicle 14 Lane center 15 Driving lane 16 Leading vehicle detection apparatus 17 Case 18 Laser irradiation range 19 Reflector 21 Turn signal lamp sensor 22 Vehicle speed sensor 23 Mark 201 Light projection window 202 Light reception window 203 Reflection mirror 204 Stepping motor 205 Laser light receiving element 206 Laser light emitting element 207 Amplifying circuit 208 Driving circuit 209 Motor driving circuit 210 CPU

Claims (6)

Light emitting means for emitting laser light, scanning means for scanning the laser light emitted from the light emitting means in the front left and right direction of the host vehicle, light receiving means for receiving reflected light of the laser light, and light received by the light receiving means In a preceding vehicle detection device comprising preceding vehicle detection means for detecting a preceding vehicle from a laser beam,
Reflector height detecting means for detecting the height of the reflector provided at the rear of the detected preceding vehicle;
Lane change operation detection means for detecting the lane change operation of the preceding vehicle or the lane change operation of the host vehicle,
The scanning means scans the laser beam in the left-right direction at a predetermined elevation angle predetermined as an initial value, the preceding vehicle detection means detects the preceding vehicle, and the lane change operation detection means detects the preceding vehicle or the host vehicle. When a lane change operation is detected, the reflector height of the preceding vehicle detected by the reflector height detecting means is determined in a predetermined lateral range including the detected preceding vehicle at the next scanning. A preceding vehicle detection device, wherein laser light is scanned in the left-right direction at an elevation angle included in an irradiation range, and laser light is scanned in the left-right direction at the predetermined elevation angle except for the predetermined left-right direction range. The lane change operation detecting means detects a lane center of a lane in which the host vehicle travels,
When the lateral deviation amount between the center position in the width direction of the preceding vehicle detected by the preceding vehicle detecting means and the center of the lane exceeds a predetermined value, it is detected that the preceding vehicle is performing a lane changing operation. The preceding vehicle detection device according to claim 1. The lane change operation detecting means uses a center position of two reflectors provided at a rear portion of the preceding vehicle detected by the preceding vehicle detecting means as a center position in the width direction of the preceding vehicle. Item 3. The preceding vehicle detection device according to Item 2. A yaw rate sensor for detecting the yaw rate of the host vehicle or a rudder angle sensor for detecting the rudder angle;
When the lane change operation detecting means detects the lane center, a curvature of the lane is obtained from an output value of the yaw rate sensor or rudder angle sensor, and the lane center is estimated based on the curvature. Item 4. The preceding vehicle detection device according to Item 2 or 3. It has a turn signal lamp sensor that detects turning on / off of the turn signal lamp of its own vehicle,
The lane change operation detecting means detects the turn signal lamp when the turn signal lamp sensor detects lighting of the turn signal lamp, and when the direction indicated by the turn signal lamp coincides with the detected yaw rate or rudder angle direction, The preceding vehicle detection device according to claim 4, wherein it is detected that a lane change operation is being performed. A turn signal lamp sensor for detecting turning on / off of the turn signal lamp of the own vehicle;
A yaw rate sensor for detecting the yaw rate of the host vehicle or a rudder angle sensor for detecting a rudder angle;
The lane change operation detecting means detects the turn signal lamp when the turn signal lamp sensor detects lighting of the turn signal lamp, and when the direction indicated by the turn signal lamp coincides with the detected yaw rate or rudder angle direction, The preceding vehicle detection device according to any one of claims 1 to 3, wherein it is detected that a lane change operation is being performed.

Images