JP3719691B2 - Vehicle recognition device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle recognition device that uses a radar tracking device that tracks a front vehicle, and more particularly, to a vehicle recognition device that can appropriately determine whether a front vehicle is traveling on a vehicle lane on a curved road.
[0002]
[Prior art]
There is a millimeter wave radar device that emits millimeter wave radio waves toward the front of a vehicle to prevent a rear-end collision and the like, and calculates the traveling speed and distance between vehicles from the reflected wave. When the radar apparatus detects the front vehicle, the inter-vehicle distance D and the relative speed (V2 -V1) are calculated to determine whether or not speed control for preventing a rear-end collision is necessary.
[0003]
FIGS. 4A and 4B are diagrams for explaining vehicle recognition based on the positional relationship of the vehicles. FIG. 4A shows a target (front vehicle) undetected and FIG. 4B shows a target detection. This will be described below with reference to the drawings.
On a road with two driving lanes on one side, vehicle A (own vehicle) does not detect vehicle B in the adjacent lane (front vehicle) in the vehicle positional relationship at time t1 as shown in FIG. However, in the positional relationship of the vehicle at time t2 as shown in FIG. 4B, the A vehicle detects the B vehicle in the adjacent lane. However, the detection by the radar device can only be found that there is a target (vehicle) in the radar beam, and the vehicle traveling in the traveling lane of the own vehicle has been detected, or the road ahead is curved. It is difficult to clearly distinguish whether the vehicle running in the adjacent lane has been detected (corresponding to FIG. 4B) because it has been on the extension line of the own vehicle lane. Therefore, in spite of the detected vehicle traveling in the adjacent lane, there is a problem that the vehicle is decelerated when traveling in the inter-vehicle distance control.
[0004]
Vehicles traveling in front of the vehicle lane will continue to be detected by the radar device, and vehicles traveling in the curved adjacent lane will no longer be detected by the radar device if they cross the front of the vehicle lane. It is possible to distinguish between the two by using. Therefore, even if the front vehicle is detected by the radar device, the speed control or the like is not performed immediately, the delay time is provided and the front vehicle is detected again by the radar device (or continuously detected during that time), Judging that there was a vehicle in front of the vehicle lane, measures such as inter-vehicle distance control were taken.
[0005]
[Problems to be solved by the invention]
In the above method, in order to determine whether the preceding vehicle is in the own vehicle lane or the adjacent lane, the longer the delay time is, the more reliable the determination is. However, holding the determination for a long time causes a problem that if it is determined that the preceding vehicle is in the own vehicle lane, the vehicle will collide with the preceding vehicle with a delay in deceleration. In other words, there is a conflict between improving the reliability of judgment and the timing for appropriate deceleration.
[0006]
The present invention is a vehicle recognition system that can determine the position of the front vehicle at an appropriate timing without sacrificing reliability while minimizing the time required to determine whether the front vehicle is in the own vehicle lane. An object is to provide an apparatus.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a vehicle recognition device that is provided in a host vehicle, outputs a detection radar in front of the host vehicle, and recognizes a front vehicle located in the area of the detection radar.
Calculation means for calculating an inter-vehicle distance D from the host vehicle to the front vehicle and a speed V of the front vehicle;
A radius of curvature estimating means for estimating a radius of curvature R of the traveling lane of the preceding vehicle;
Estimating means for estimating a traveling time T for the front vehicle to pass through the detection radar area on a curved road based on the inter-vehicle distance D speed V and the curvature radius R;
Judgment means for judging that the front vehicle is traveling in the own vehicle lane when it is detected that the front vehicle continues to be located within the area of the detection radar beyond the time estimated by the estimation means. It is characterized by comprising.
[0008]
Further, the estimation means includes a movement distance calculation means for calculating a movement distance L that the front vehicle moves across the detection width X of the detection radar based on the curvature radius R and the inter-vehicle distance D.
From the travel distance L and the speed V, a travel time T for the front vehicle to travel the travel distance L is estimated,
The determination means includes a time measuring means for measuring a detection time t for continuously detecting the front vehicle in the detection radar,
When the detection time t is longer than the travel time T, it is determined that the preceding vehicle is traveling in the own vehicle lane.
[0009]
The curvature radius estimating means is characterized in that the curvature radius R of the traveling lane is calculated based on map information installed in the own vehicle and corresponding to the position of the preceding vehicle.
Further, the determination means has a curve road detection means for detecting that the host vehicle is traveling on a curved road, and detects that the host vehicle is traveling on the curve road by the curve road detection means. , The judgment is canceled.
[0010]
【Example】
FIG. 1 is a diagram for explaining a system configuration of a vehicle recognition device according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining a principle of the vehicle recognition device according to an embodiment of the present invention. This will be described below with reference to the drawings.
Reference numeral 1 denotes a millimeter wave radar device using the Doppler effect installed in front of the own vehicle (A vehicle), which detects a reflected wave of a beam irradiated toward the front and outputs it to the subsequent stage. Reference numeral 2 denotes a vehicle speed sensor for measuring the speed V1 of the own vehicle (A vehicle). Reference numeral 3 denotes a navigation device that detects the vehicle position and calculates a curved road radius R of the road ahead based on the map information stored in the CD-ROM 31. A yaw rate sensor 4 detects whether or not the vehicle is traveling on a curved road. 5 performs signal processing of the reflected wave detected by the radar device 1 and measures the inter-vehicle distance D and the relative speed (V2 -V1) to the front vehicle (B vehicle). A microcomputer 51 that performs control, and further determines whether the preceding vehicle is in the own vehicle lane using equations (1) to (5) described later based on data from the vehicle speed sensor 2 and the navigation device 3; This is a millimeter wave radar signal processing ECU composed of memories such as ROM 52 and RAM 53 in which various data are stored. A cruise ECU 6 controls the speed by adjusting the throttle actuator 7 according to an instruction from the millimeter wave radar signal processing ECU 5. As a result, a certain distance between the vehicle and the front vehicle is maintained.
[0011]
FIG. 2 shows a state in which the vehicle B crosses (diagonally) the beam area of the radar device 1 of the vehicle A having a detected beam width X (m) while the vehicle B travels on a road having a curved road radius R (m). . In the L section, the radar apparatus 1 detects the B car, and the radar apparatus 1 does not detect the B car before and after that.
At the position of the B vehicle immediately before entering the beam area of the radar device 1,
R × Sin θ1 = D (1), that is, θ1 = Sin ⁻¹ (D / R) (1) ′ is established, and the beam area of the radar apparatus 1 is determined. At the position of Car B just after leaving,
R × Cos θ ² + X = (R ² −D ² ) ^1/2 ... (2) Formula, that is, θ 2 = Cos ⁻¹ (((R ² −D ² ) ^1/2 −X) / R).・ ・ (2) 'relationship is established. In addition, the movement angle θ of the B car in the meantime is
θ = θ2−θ1 (3), that is, θ = Cos ⁻¹ (((R ² −D ² ) ^1/2 −X) / R)
−Sin ⁻¹ (D / R)... (3) ′, and the travel distance L (m) of the B vehicle during this period is
L = (πR / 180) × (Cos ⁻¹ (((R ² −D ² ) ^1/2 −X) / R) −Sin ⁻¹ (D / R)) (4) . That is, the travel distance L that travels while the B vehicle is detected by the radar is obtained from R and D.
[0012]
Here, the information from the navigation device 3 is used as the curved road radius R (m). The speed V2 (m / s) of the B vehicle is known from the millimeter wave radar device 1 using the Doppler effect, and the vehicle speed V1 (m / s) is obtained from the vehicle speed sensor 2. Therefore, the speed V2 of the B car can be calculated. Therefore, the travel time T (s) for the vehicle B to travel the travel distance L (m) is
T = L / V2 (5) That is, if a forward vehicle is detected continuously for a time T or more after the target (in this case, vehicle B) is detected for the first time, it can be determined that the forward vehicle is present in the own vehicle lane.
[0013]
If there is no information from the navigation device 3 regarding the curved road radius R, a preset value (for example, a curved road radius of 1000 m) is substituted. On a curved road with a radius of less than this, there will be no practical inconvenience because it will be shifted to the side where the judgment time has a margin (to the safe side).
When determining whether the preceding vehicle (vehicle B) is in its own lane or in an adjacent lane by the above method, the direction of the radar beam does not change, that is, the own vehicle goes straight ahead. It is assumed that Therefore, if the vehicle enters a curved road, this method makes an erroneous determination. Therefore, if the radar device 1 detects that the vehicle is traveling on a curved road based on the output from the yaw rate sensor 4 of the vehicle within the determination hold time T after the detection of the preceding vehicle, the determination is stopped. There is a need to.
[0014]
FIG. 3 is a flowchart of the processing performed by the microcomputer of the vehicle recognition apparatus according to the embodiment of the present invention. This will be described below with reference to a flowchart.
In step S1, it is determined whether or not a preceding vehicle has been detected, and if detected, the process proceeds to step S2, and if not detected, the process proceeds to step S13. That is, it is determined that the radar apparatus 1 of the own vehicle has changed from the state that has not been detected until now to the detection state (detection of entering the section L).
[0015]
In step S2, the counter is incremented by one and the process proceeds to step S3. That is, the counter (clock) is advanced by one in order to count the time continuously detected by the radar device 1 of the own vehicle.
In step S3, the speed V2 of the front vehicle is calculated and the process proceeds to step S4. That is, the relative speed (V1−V2) is obtained by the millimeter wave radar device 1 using the Doppler effect, and the speed V1 of the own vehicle is obtained from the vehicle speed sensor 2 to calculate the speed V2 of the front vehicle.
[0016]
In step S4, the inter-vehicle distance D is calculated, and the process proceeds to step S5. That is, the distance from the front vehicle is calculated by the radar device 1.
In step S5, it is determined whether there is data on the curvature radius R of the curved road by the navigation device 3. If there is data, the process proceeds to step S6, and if not, the process proceeds to step S7. That is, it is determined whether or not there is a curved road radius R for performing calculation according to the equation (4).
[0017]
In step S6, based on the curved road radius R detected by the navigation device 3, the moving distance L of the front vehicle is calculated by the equation (4). That is, the distance that the front vehicle crosses in front of the host vehicle (continuously detected by the radar) is calculated using the radius of curvature R of the section in which the front vehicle is traveling, obtained by the navigation device 3. The calculation accuracy is improved by using the radius of curvature by the navigation device.
[0018]
In step S7, the moving distance L of the front vehicle is calculated by equation (4) with the curve road radius R as a predetermined value. That is, if there is no information from the navigation device 3 regarding the curve road radius R, a preset value (for example, a curve road radius of 1000 m) is substituted. On a curved road with a radius of less than this, there will be no practical inconvenience because it will be shifted to the side where the judgment time has a margin (to the safe side).
[0019]
In step S8, a travel time T corresponding to the travel distance L of the preceding vehicle is calculated, and the process proceeds to step S9. That is, the traveling time T in which the front vehicle theoretically crosses the front of the own vehicle lane is calculated by the equation (5). That is, on a curved road, a time T from the time when the front vehicle normally approaches the detection radar area to the time when it exits (passes through the area) is estimated.
In step S9, it is determined whether the yaw rate sensor 4 has detected a curve, and if a curve is detected, the process proceeds to step S12, and if no curve is detected, the process proceeds to step S10. That is, when it is determined whether the preceding vehicle (B vehicle) is in the own vehicle lane or in the adjacent lane, it is assumed that the own vehicle goes straight and the direction of the radar beam does not change.
[0020]
In step S10, it is determined whether or not the counter has reached T. If T, the process proceeds to step S11, and if not, the process returns to step S1. That is, it is determined whether or not the radar apparatus 1 has detected the front vehicle for the moving time T.
In step S11, it is determined that the preceding vehicle is in the own vehicle lane, and the process ends. That is, since it is determined that the front vehicle is in the self-running lane, the millimeter wave radar signal processing ECU 5 instructs the cruise ECU 6 to perform the inter-vehicle distance control according to the inter-vehicle distance and the relative speed.
[0021]
In step S12, the determination is stopped and the process proceeds to step S13. That is, since the direction of the radar beam changes when the own vehicle enters the curved road, this method makes an erroneous determination. Therefore, when the yaw rate sensor 4 of the own vehicle detects a curve within the determination hold time T after the radar device 1 detects the front vehicle, the processing from step S1 to step S13 is stopped and the processing proceeds to another processing. For example, an alarm or the like informs that the judgment has been stopped, and the driver uses manual control as necessary. By using the yaw rate sensor, the accuracy of judgment is improved.
[0022]
In step S13, the counter is reset and the process ends. In other words, this determination can be made only when the preceding vehicle is continuously detected or when the host vehicle is traveling straight, so the counter is reset and the procedure is repeated from the beginning. In this case, it is determined that the vehicle crosses the curve road or is temporarily interrupted, and the inter-vehicle distance control such as decelerating the vehicle is not performed.
[0023]
In this flowchart, the processing from step S3 to step S8 may be performed only once for the first time and may be omitted for the second and subsequent times. That is, even if the travel time T is calculated assuming that the speed V2, the inter-vehicle distance D, and the curve road radius R of the front vehicle do not change while the front vehicle travels the travel distance L, there is almost no error.
As described above, in the present embodiment, the determination suspension time for determining whether or not the vehicle is in the own vehicle lane is determined based on the theoretical time when the front vehicle crosses the radar beam while traveling on a curved road. Inconvenience due to delayed judgment does not occur.
[0024]
【The invention's effect】
As described above, according to the present invention, the time required to determine whether the preceding vehicle is in the own vehicle lane can be minimized, and determination can be made at an appropriate timing without sacrificing reliability.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a system configuration of a vehicle recognition apparatus according to an embodiment of the present invention.
FIG. 2 is a diagram for explaining the principle of a vehicle recognition apparatus according to an embodiment of the present invention.
FIG. 3 is a flowchart of processing performed by a microcomputer of the vehicle recognition apparatus according to the embodiment of the present invention.
FIGS. 4A and 4B are diagrams for explaining vehicle recognition based on a vehicle positional relationship, in which FIG. 4A is a target (front vehicle) undetected and FIG. 4B is a target detection;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Radar apparatus 4 ... Yaw rate sensor 2 ... Vehicle speed sensor 5 ... Millimeter wave radar signal processing ECU
3 ... Navigation device 6 ... Cruise ECU

Claims (4)

In the vehicle recognition device provided in the own vehicle, outputting a detection radar in front of the own vehicle, and recognizing a front vehicle located in the area of the detection radar,
Calculating means for calculating an inter-vehicle distance D from the host vehicle to the front vehicle and a speed V of the front vehicle;
A radius of curvature estimating means for estimating a radius of curvature R of the traveling lane of the preceding vehicle;
Estimating means for estimating a traveling time T for the front vehicle to pass through the detection radar area on a curved road based on the inter-vehicle distance D speed V and the curvature radius R;
Judgment means for judging that the front vehicle is traveling in the own vehicle lane when it is detected that the front vehicle continues to be located within the area of the detection radar beyond the time estimated by the estimation means. And a vehicle recognition device. The estimation means includes a movement distance calculation means for calculating a movement distance L that the front vehicle moves across the detection width X of the detection radar based on the curvature radius R and the inter-vehicle distance D.
From the travel distance L and the speed V, a travel time T for the front vehicle to travel the travel distance L is estimated,
The determination means includes a time measuring means for measuring a detection time t for continuously detecting the front vehicle in the detection radar,
2. The vehicle recognition apparatus according to claim 1, wherein when the detection time t is longer than the travel time T, the front vehicle determines that the vehicle is traveling in its own lane.   3. The vehicle according to claim 1, wherein the curvature radius estimation unit is configured to calculate a curvature radius R of a traveling lane based on map information installed in the own vehicle and corresponding to a position of the front vehicle. Recognition device.   The determination means has a curve road detection means for detecting that the host vehicle is traveling on a curved road, and if the curve road detection means detects that the host vehicle is traveling on a curve road, The vehicle recognition device according to claim 1 or 2, wherein

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