JPH07128443A - In-vehicle radar device - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to an on-vehicle radar device, and an object thereof is to prevent a traveling vehicle in a lane adjacent to a traveling lane of the own vehicle from being erroneously detected as a preceding vehicle. [Structure] The radar device M1 detects a relative distance to a preceding vehicle in the traveling direction of the own vehicle. Spreading angle varying means M
2 changes the spread angle of the radar beam emitted by the radar device M1. The divergence angle control means M3 controls the divergence angle varying means M2 so that the divergence angle of the radar beam becomes narrower as the detected relative distance becomes longer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle radar device,
The present invention relates to an on-vehicle radar device mounted on a vehicle to detect a target object.

[0002]

2. Description of the Related Art Conventionally, various devices have been developed and mounted on a vehicle for the purpose of improving a driver's driving low range and safety, and the distance and relative speed to a surrounding object such as a preceding vehicle. Development of a radar device for detecting the is also active. As a radar device, one using a radio wave such as a millimeter wave or one using a laser beam has been proposed.

A conventional radar apparatus is, for example, an actual Kaihei 3-9.
As described in Japanese Patent No. 5980, the divergence angle of the laser light is changed according to the vehicle speed to detect a preceding vehicle in a short distance and a wide range at low speed traveling, and to detect a preceding vehicle in a long distance and a narrow range at high speed traveling. ing.

[0004]

The conventional radar device is
Since the detection range is short and wide during low-speed traveling, there is a problem that a traveling vehicle in an adjacent lane is likely to be detected when there is no preceding vehicle on the traveling lane of the own vehicle.

Further, there is also a method of recognizing the white line from the correlation between the image data obtained by the image sensor and the template of the white line to detect the width of the traveling lane of the own vehicle and use only the inside of the traveling lane of the own vehicle as the detection area. Although it is known, there is a problem in that the recognition device for detecting the width of the traveling lane of the own vehicle is required, resulting in high cost and impracticality.

The present invention has been made in view of the above points,
An object of the present invention is to provide an in-vehicle radar device that does not erroneously detect a traveling vehicle in a lane adjacent to the own vehicle's traveling lane as a preceding vehicle by narrowing the spread angle of the radar beam as the relative distance to the preceding vehicle increases. And

[0007]

FIG. 1 shows the principle of the present invention.

In the figure, the radar device M1 detects the relative distance to the preceding vehicle in the traveling direction of the own vehicle.

The divergence angle varying means M2 varies the divergence angle of the radar beam emitted by the radar device M1.

The divergence angle control means M3 controls the divergence angle varying means M2 so that the divergence angle of the radar beam becomes narrower as the detected relative distance becomes longer.

[0011]

According to the present invention, according to the relative distance to the preceding vehicle, the longer the relative distance is, the narrower the spread angle of the radar beam is. Therefore, only the preceding vehicle in the traveling lane of the own vehicle is detected and the traveling in the adjacent lane is detected. False detection of the vehicle as a preceding vehicle is prevented.

[0012]

FIG. 2 is a block diagram of an embodiment of an on-vehicle radar device according to the present invention.

In the figure, a transmitter / receiver 10 for transmitting and receiving a triangular modulated wave is provided at a predetermined position on the front of the vehicle to detect a target object such as a preceding vehicle. And this transceiver 10
The detection signal from is supplied to the distance / relative speed calculation circuit 12, and the relative distance and relative speed to the front obstacle are calculated. Specifically, the relative distance and the relative velocity are calculated by taking the sum and difference of the transmission triangular modulation wave and the reception triangular modulation wave. The output of the distance / relative speed calculation circuit 12 is supplied to the preceding vehicle distance determination circuit 14. In the preceding vehicle distance determination circuit 14, this distance / relative speed calculation circuit 12
The current distance to the preceding vehicle is determined from the output from the vehicle and the momentum of the current vehicle. The output from the distance / relative speed calculation circuit 12 is also supplied to the danger determination circuit 16, and when the distance to the front obstacle or the relative speed exceeds a predetermined allowable value, a warning sound is given to the vehicle driver. Gives an alarm.

The distance information to the preceding vehicle calculated by the preceding vehicle distance determining circuit 14 is further supplied to the turning angle determining circuit 18. The rotation angle determination circuit 18 determines the rotation angle θ for rotating the transceiver 10 based on the inter-vehicle distance from the preceding vehicle, the steering angle signal from the steering wheel steering angle detection device 20, and the vehicle speed signal from the vehicle speed detection device 22. To do.

After the turning angle θ _S is determined in this way, the turning angle determining circuit 18 sends a turning angle signal θ _S to the transceiver turning device 24 to turn the transceiver 10.

FIG. 3 shows a flowchart of the tracking process of the device of the present invention. In the figure, in step S10, it is determined whether or not the target preceding vehicle is detected. Specifically, when the radar reflected wave from the preceding vehicle is received by the transmitter / receiver 10 and the relative distance and relative speed with respect to the preceding vehicle are calculated by the distance / relative speed calculation circuit 12, there is a preceding vehicle, and the relative distance and relative speed. When is not calculated, it is determined that there is no preceding vehicle.

If it is determined in step S10 that there is a preceding vehicle, the process proceeds to step S20. If it is determined that there is no preceding vehicle, the relative distance R _i is set to a predetermined value R ₀ in step S30, and the process proceeds to step S20. The predetermined value R ₀ is, for example, 5
It is 0m.

Next, in step S20, the steering angle θ _{H of the} vehicle is
Then, it is determined whether or not the vehicle is in a curve, that is, whether or not the absolute value of the steering angle is equal to or greater than the predetermined angle θ _{THL for a} certain period of time. If it is not in the curve, the process proceeds to step S40 and the relative distance R _i and the lane width W of the road (W is a constant value, for example, W =
3.5 m) is used to determine the scanning range θ by the following equation.

Θ = ± tan ⁻¹ W / R _i (1) As shown in FIG. 4, when the relative distance R ₁ from the own vehicle 30 to the preceding vehicle 31 is, the scanning range θ ₁ is θ ₁ = ± tan ^{− 1}
W / R ₁ and the relative distance to the preceding vehicle 32 is R ₂
, The scanning range θ ₂ is θ ₂ ± tan ^-1 W / R
It becomes ₂ . Thereafter, in step S50, the transmitter / receiver rotating device 20 is driven to rotate the transmitter / receiver 10 at every minute angle within the scanning range θ of the equation (1) to perform scanning, and then the process proceeds to step S90.

If it is determined in step S20 that the vehicle is in a curve, the process proceeds to step S60, where the curve R of the curve R is calculated based on the steering angle θ _H from the steering wheel steering angle detection device 20 and the vehicle speed V from the vehicle speed detection device 22. Calculate the radius of curvature ρ.

Ρ = (1 + K ₁ × V ² ) × K ₂ / θ _H (2) However, K ₁ K ₂ is a constant.

The vehicle speed V, the steering angle θ _H, and the radius of curvature ρ
The relationship with is as shown in FIG.

Next, in step S70, the steering angle θ _S is calculated by the following equation using the relative distance R _i and the radius of curvature ρ.

Θ _S = sin ⁻¹ R ₁ / 2ρ (3) Further, the scanning range θ is calculated by the following equation.

Θ = θ _S ± tan ⁻¹ W / R _{i In other} words, when the vehicle is traveling in a curve, the steering angle θ _S based on the radius of curvature ρ of this curve is calculated and the scanning range θ _{i of the} straight road is calculated. = ± tan ⁻¹ W / R _i and the above steering angle θ _s , the scanning range θ _i = θ _S ± tan ⁻¹
W / R _i is set.

Thereafter, in step S80, the transmitter / receiver rotating device 20 is driven to rotate the transmitter / receiver 10 at every minute angle within the scanning range θ of the above formula (3) to perform scanning, and then in step S90. Proceed to.

In step S90, step S50 or S
In the scan performed at 80, the transmitter / receiver rotating device 20 is driven to rotate the transmitter / receiver 20 such that the reception angle of the radar reflected wave becomes the maximum scan angle θ _T.

Next, in step S100, the relative distance and relative speed calculated by the distance / relative speed calculating circuit 12 are monitored by the danger judging circuit 16, and in step S110, the relative distance and relative with the preceding vehicle monitored by the danger judging circuit 16 are monitored. From the speed, it is determined whether or not the vehicle is in a dangerous state. In the dangerous state, an alarm such as a buzzer or blinking of a lamp is issued in step S120, and then the process returns to step S10.
The process returns from step 10 to step S10 and the process is repeated.

As described above, since the scanning range is determined so that the road width at a position separated by the relative distance can be scanned according to the relative distance to the preceding vehicle, the radar beam scans only the traveling lane of the own vehicle. Therefore, it is possible to detect only the preceding vehicle in the traveling lane of the own vehicle without scanning the vehicle in the adjacent lane without scanning the adjacent lane.

Although the divergence angle of the radar beam is changed by scanning in the above embodiment, the divergence angle may be changed by changing the focal position of the emitted radar beam.

However, in the method of varying the focal position of the radar beam to vary the spread angle of the radar beam, when the spread angle of the radar beam is set to the wide angle side, the energy per unit angle of the radar beam decreases and the detection The accuracy decreases. On the other hand, in the method of varying the rotation angle of the radar device to vary the divergence angle of the radar beam as in the present embodiment, it is possible to obtain the detection accuracy in which the divergence angle of the radar beam is constant from the wide angle side to the narrow angle side. it can.

[0032]

As described above, according to the in-vehicle radar device of the present invention, the longer the relative distance to the preceding vehicle is, the narrower the spread angle of the radar beam is. It is extremely useful in practice, because it will not be erroneously detected as a preceding vehicle.

[Brief description of drawings]

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

FIG. 2 is a block diagram of the device of the present invention.

FIG. 3 is a flowchart of tracking processing according to the present invention.

FIG. 4 is a diagram for explaining a scanning range.

FIG. 5 is a diagram showing a relationship between a radius of curvature, a vehicle speed, and a steering angle.

[Explanation of symbols]

 10 Transceiver 14 Preceding vehicle distance determination circuit 18 Rotation angle determination circuit 20 Steering wheel steering angle detection device 22 Vehicle speed detection device 24 Transceiver rotation device M1 Radar device M2 Spreading angle varying means M3 Spreading angle control means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G01S 17/93

Claims (2)

[Claims] 1. A radar device for detecting a relative distance to a preceding vehicle in a traveling direction of the host vehicle, a spread angle varying means for varying a spread angle of a radar beam emitted by the radar device, and the detected relative distance. The vehicle-mounted radar device having a divergence angle control means for controlling the divergence angle varying means so as to narrow the divergence angle of the radar beam as the length becomes longer. 2. The on-vehicle radar device, wherein the divergence angle changing means rotates the radar device and sets the rotation angle as a divergence angle of the radar beam.