JP2803393B2 - Automotive radar equipment - Google Patents

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, and more particularly to an improved on-vehicle radar device for reliably detecting a preceding vehicle even on a curved road.

[0002]

2. Description of the Related Art Conventionally, a preceding vehicle detecting device for a vehicle for detecting an inter-vehicle distance to a preceding vehicle, a relative speed, and the like for the purpose of performing automatic following travel or the like has been known. Conventionally, a laser radar device has been used as such a preceding vehicle detection device. However, when the preceding vehicle and the own vehicle do not exist on the same straight road, for example, on a curved road, the laser radar device is used. If the direction of the laser beam emitted from the device is fixed, the preceding vehicle cannot be detected. Therefore, conventionally, a scanning laser radar device that scans a laser beam within a predetermined range or a steer type laser radar device that detects a curved track by some means and changes the beam in accordance with the curve direction has been proposed. ing. For example, in a vehicle radar sensor disclosed in Japanese Patent Application Laid-Open No. 51-30490, a radiator of the radar sensor is linked with a steering wheel of a vehicle, and a radar beam radiated from the radiator in accordance with a steering angle of the steering wheel. It changes the direction.

[0003]

However, in such a configuration in which the radar device is rotationally driven in accordance with the steering angle of the steering wheel, the preceding vehicle is not always required depending on the running state of the vehicle and the positional relationship with the preceding vehicle which is the target vehicle. There was a problem that the car could not be tracked. FIG. 4 shows the relationship between curved roads having various radii of curvature and the steering angles at that time when the vehicle speed is taken as a parameter. As can be seen from the figure, even when traveling on a curved road having the same radius of curvature, the steering angle of the steering wheel takes a different value depending on whether the vehicle speed of the host vehicle increases or decreases. Therefore, in this case, when the radar device is rotationally driven based only on the steering wheel angle, when the vehicle speed is high, the radar device is largely rotated and driven in accordance with the large steering wheel angle. Will occur. In addition, as shown in FIG. 5, when the distance between the target vehicle and the host vehicle is large on a curved road having the same radius of curvature, the turning angle of the radar device for tracking should be different between L2 and L1 when the distance is small. In spite of the fact that the steering angle of the steering wheel of the own vehicle is the same, there is a problem that the radar device is also driven to rotate by the same angle and therefore cannot be tracked.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide an on-vehicle radar device capable of reliably tracking a preceding vehicle irrespective of its own vehicle speed or the inter-vehicle distance to the preceding vehicle. Is to provide.

[0005]

In order to achieve the above object, a vehicle-mounted radar device according to the present invention has a radar means 1 for detecting an obstacle ahead and a vehicle speed for detecting the own vehicle speed as shown in FIG. Detecting means 2; steering angle detecting means 3 for detecting a steering angle of the own vehicle; inter-vehicle distance calculating means 4 for calculating an inter-vehicle distance to a preceding vehicle based on a detection signal from radar means; Determining means 5 for determining whether or not the vehicle is traveling on a curved road based on the detection signal; and when the determining means determines that the vehicle is traveling on a curved road, the vehicle speed, the steering angle and the preceding vehicle And a tracking means 6 for rotatingly driving the radar means 1 based on the inter-vehicle distance.

[0006]

As described above, the on-vehicle radar device of the present invention does not rotate the radar means 1 in association with only the steering angle of the vehicle, but also considers the own vehicle speed and the inter-vehicle distance to the preceding vehicle. By rotating and driving the radar means 1, the preceding vehicle is reliably captured regardless of the traveling state of the own vehicle or the positional relationship with the preceding vehicle.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a vehicle-mounted radar device according to the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of this embodiment. In the figure, a transmitter / receiver 10 for transmitting and receiving a triangular modulated wave as a radar means is provided at a predetermined position in front of a vehicle, and detects a forward obstacle such as a preceding vehicle. The detection signal from the transmitter / receiver 10 is input to the distance / relative speed calculation circuit 12, where the distance to the obstacle ahead and the relative speed are calculated. Specifically, the distance and the relative speed are calculated by calculating the sum and difference between the transmission triangular modulation wave and the reception triangular modulation wave. The output of the distance / relative speed calculation circuit 12 is input to the preceding vehicle distance determination circuit 14.
The preceding vehicle distance determination circuit 14 determines the current distance to the preceding vehicle based on the output from the distance / relative speed calculation circuit 12 and the current vehicle momentum. The output from the distance / relative speed calculation circuit 12 is also input to the danger determination circuit 16, and when the distance to the obstacle ahead or the relative speed exceeds a predetermined allowable value, a warning sound or the like is given to the vehicle driver. Give an alarm.

The distance information to the preceding vehicle calculated by the preceding vehicle distance determination circuit 14 is further output to a rotation angle determination circuit 18. In the turning angle determination circuit 18, a steering angle signal from a steering angle detection device 20 and a distance between the vehicle and the preceding vehicle,
Based on the vehicle speed signal from the vehicle speed detection device 22, the transceiver 10
Is determined.

In the present embodiment, the turning angle determination circuit 18 determines the turning angle θS of the transceiver 10 from the following distance L from the preceding vehicle, the steering angle θH of the own vehicle, and the vehicle speed V according to the following equations. . ^{That, sin -1 (L / 2ρ)} ρ = (1 + K1 V 2) · K2 / θH where, K1 and K2 are constants.

After the rotation angle θS is determined in this manner, the rotation angle determination circuit 18 sends a rotation angle signal θS to the transmitter / receiver rotation device 24 to rotate the transceiver 10.

Hereinafter, the operation of the on-vehicle radar device according to the present embodiment will be described in detail with reference to the flowchart of FIG. First, in S301, it is determined whether or not the vehicle is traveling substantially straight. In this determination, the steering angle detection device 2
The steering angle θH signal output from 0 is used. If the steering angle θTHL is equal to or greater than the predetermined steering angle θTHL for a certain period of time, it is determined that the vehicle is traveling on a curved road. Road, that is, determined as YES. If it is determined in this step that the vehicle is traveling on a substantially straight road, the flow shifts to the next step S302 to monitor the distance and the relative speed. Then, it is determined in S303 whether or not the preceding vehicle as the target has been detected. When the preceding vehicle is detected, the process proceeds to the next S304, and it is determined whether the relative speed monitored in S302 is equal to or lower than a predetermined relative speed Vro. If NO in this step, that is, if it is determined that the relative speed is equal to or higher than Vro, it means that there is a preceding vehicle and the relative speed with the preceding vehicle is equal to or higher than a predetermined value, so that a dangerous case may occur. Means S3
The process proceeds to the danger determination step 18, and if dangerous, S 3
At 19, an alarm and a brake control are performed.

On the other hand, if YES in S304, that is, if the preceding vehicle is detected and the relative speed with respect to the preceding vehicle is equal to or lower than the predetermined value Vro, the process proceeds to S305. In S305, it is determined whether or not the preceding vehicle is following, that is, the target preceding vehicle is detected, and the relative speed with respect to the preceding vehicle is equal to or lower than the predetermined value Vro for a predetermined time T0. In this case, it is determined that the vehicle is following the preceding vehicle, and the preceding vehicle following flag is turned ON. Then, the flow shifts to S306, where the temporal change of the distance to the preceding vehicle and the relative speed are stored in the memory. on the other hand,
If the target preceding vehicle is not detected in S303, that is, if NO is determined in this step, the process proceeds to S307, and the preceding vehicle following flag is turned off.

As described above, when the own vehicle is traveling on a straight road, it is determined whether or not the vehicle is following the preceding vehicle, and the preceding vehicle following flag is set to ON or OFF, and the vehicle follows the preceding vehicle. When the vehicle is traveling on a curved road, it is necessary to drive the radar means to supplement the preceding vehicle, as described above. The processing for this is the step after S308, and in S301, N
If O, that is, if it is determined that the vehicle is traveling on a curved road, the process first proceeds to S308. In this S308, it is determined whether or not the preceding vehicle following flag is ON. S3 mentioned above
If the preceding vehicle following flag is set to ON in 05, YES is determined in this step, and the next S309
And the following distance L to the preceding vehicle, steering angle θH, vehicle speed V
Enter Then, it calculates the rotation angle θS transceiver by the aforementioned formula in ^{S310, sin -1 (L / 2ρ} ) ρ = (1 + K1 V 2) · K2 / θH. And S3
13, the rotation angle θS calculated by the transmitter / receiver rotation device 20
Only the transceiver 10 is driven to track the preceding vehicle.

On the other hand, if NO in S308, that is, if the preceding vehicle follow-up flag is set to OFF in S307, the inter-vehicle distance to the preceding vehicle is fixed to a certain value and the rotation angle of the transceiver is determined. I do. That is, in S311, the steering angle θH and the vehicle speed V are input, and in S312, a fixed value R0 is input as the inter-vehicle distance L to the preceding vehicle, and the rotation angle is calculated in accordance with the above-described equation.

After the rotation angle of the transceiver 10 is calculated and driven in this way, the distance and the relative speed are monitored again, and it is determined in S315 whether or not the preceding vehicle as the target has been detected. If the preceding vehicle is detected, S is used to determine whether the current distance and relative speed are safe.
If the process proceeds to 318 and it is determined that there is danger, an alarm is given or brake control is performed in S319. On the other hand, if the preceding vehicle has not been detected, the flow shifts to S316 to proceed to S31.
The value of the distance R0 set in step 2 is changed and the transceiver 10 is driven to rotate to detect the target again. If a target is detected, a danger determination is made in S318. If no target is detected for a predetermined time T0, it is determined that there is no preceding vehicle, and the preceding vehicle flag is set to OF.
Set to F.

As described above, in this embodiment, the preceding vehicle is not rotated based on the steering angle alone, but is rotated in consideration of the vehicle speed and the inter-vehicle distance to the preceding vehicle. Supplementation can be made surely, and the reliability of the automatic tracking system and the collision warning system can be improved.

[0018]

As described above, according to the on-vehicle radar device according to the present invention, it is possible to follow the preceding vehicle by rotating the radar means at an optimum rotation angle even on a curved road, so that the roadside can be tracked. The preceding vehicle can be reliably detected without erroneously detecting the object as the preceding vehicle, and a highly reliable system can be constructed by incorporating the object into the automatic following system or the collision warning system.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram of the present invention.

FIG. 2 is a configuration block diagram of one embodiment of the present invention.

FIG. 3 is an operation flowchart of the embodiment.

FIG. 4 is a graph illustrating a relationship between a radius of curvature of a curved road, a vehicle speed, and a steering angle. FIG. 4 is an explanatory diagram illustrating a relationship between an inter-vehicle distance and a steering angle.

FIG. 5 is an explanatory diagram showing a relationship between an inter-vehicle distance and a steering angle.

[Explanation of symbols]

 Reference Signs List 10 transceiver 14 preceding vehicle distance determination circuit 18 rotation angle determination circuit 20 steering angle detection device 22 vehicle speed detection device 24 transceiver rotation device

Claims (1)

(57) [Claims] A radar detecting means for detecting an obstacle ahead of the vehicle, a vehicle speed detecting means for detecting a speed of the vehicle, a steering angle detecting means for detecting a steering angle of the vehicle, and a preceding vehicle based on a detection signal from the radar means. An inter-vehicle distance calculating unit that calculates an inter-vehicle distance between the vehicle and the vehicle; a determining unit that determines whether the own vehicle is traveling on a curved road based on a detection signal from the steering angle detecting unit; And tracking means for rotating and driving the radar means based on the vehicle speed, the steering angle, and the inter-vehicle distance to the preceding vehicle when it is determined that the vehicle is traveling.