JP2765314B2 - 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 on-vehicle radar device having improved deflection of a radar beam for capturing a preceding vehicle at an entrance or exit of a curve.

[0002]

2. Description of the Related Art Conventionally, there has been known a preceding vehicle detecting device for detecting a distance between vehicles and a relative speed to a preceding vehicle for the purpose of securing a safe inter-vehicle distance or performing automatic following. As such a preceding vehicle detection device, a radar device, a laser radar device, and the like are conventionally used, but when the preceding vehicle and the own vehicle do not exist on the same straight line, for example, on a curved road. If the direction of the radar beam emitted from the radar device is fixed, the preceding vehicle cannot be detected. Therefore, conventionally, a scanning type laser radar device which scans a radar beam within a predetermined range or a steer type radar device which detects a curved road by some means and turns the beam according to the curved road has been proposed. I have.

For example, in a vehicle radar sensor disclosed in Japanese Patent Laid-Open Publication No. Sho 51-30490, a radiator of the radar sensor is linked with a steering wheel of a vehicle, and radiated from the radiator in accordance with a steering angle of the steering wheel. This is to change the direction of the radar beam.

Accordingly, even when the preceding vehicle and the own vehicle are both traveling on a curved road, the steering angle of the preceding vehicle and the own vehicle is almost the same, so that the radar beam is deflected according to the steering angle of the own vehicle. This makes it possible to catch the preceding vehicle.

[0005]

However, when only the preceding vehicle enters a curved road and the own vehicle is traveling on a straight road before the curved road, the steering angle of the own vehicle is equal to the steering angle of the preceding vehicle. In the configuration in which the radar beam is deflected according to the steering angle of the own vehicle, the preceding vehicle cannot be captured (the laser beam is not deflected because the vehicle is traveling on a straight road). was there.

[0006] Further, even when the preceding vehicle is traveling on a straight road out of a curved road, the steering of the preceding vehicle and the own vehicle is similarly performed even when the own vehicle is still traveling on the curved road. There was a problem that the preceding vehicle could not be caught because the angles did not match.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems of the related art, and has as its object to provide a vehicle-mounted radar device that can reliably catch a preceding vehicle even at a curve entrance.

[0008]

In order to achieve the above object, an on-vehicle radar device according to the present invention comprises a communication means 1 for receiving steering angle data transmitted from a preceding vehicle as shown in FIG. A radar 2 for detecting a preceding vehicle, an inter-vehicle distance detecting means 3 for detecting an inter-vehicle distance with the preceding vehicle, a relative speed detecting means 4 for detecting a relative speed with respect to the preceding vehicle, and a vehicle speed for detecting a vehicle speed of the own vehicle. Detecting means 5, steering angle detecting means 6 for detecting the steering angle of the own vehicle, difference calculating means 7 for calculating the difference between the steering angle of the preceding vehicle and the steering angle of the own vehicle obtained by the communication means, When the magnitude of the difference is equal to or greater than a predetermined value and the own vehicle is not traveling on a curved road, the radar is rotated based on the steering angle, the following distance, the relative speed and the vehicle speed of the preceding vehicle, and Captures a car, and the magnitude of the difference is equal to or greater than a predetermined value, and Driving means 8 a car capturing the steering angle of the vehicle, the following distance, the preceding vehicle by rotating the radar based on the relative velocity and the vehicle speed when the vehicle is traveling on a curved track
And characterized in that:

[0009]

The on-vehicle radar device according to the present invention has such a configuration, and the preceding vehicle moves on a curved road using the difference between the steering angle of the preceding vehicle and the steering angle of the own vehicle obtained by the inter-vehicle communication. Detects whether the vehicle has entered or exited the curved track, and if the preceding vehicle has entered the curved road, turns the radar based on the steering angle, inter-vehicle distance, relative speed and vehicle speed of the preceding vehicle to capture the preceding vehicle On the other hand, when the preceding vehicle exits the curved lane, the radar is rotated based on the steering angle, the following distance, the relative speed and the vehicle speed of the own vehicle to catch the preceding vehicle.

[0010]

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. A transmitter / receiver 10 for transmitting / receiving a triangular modulated wave as a radar is provided at a predetermined position in the front part of the vehicle, and detects a forward obstacle such as a preceding vehicle. And this transceiver 10
, That is, a composite signal of the transmission triangular modulation wave and the reception triangular modulation wave is input to the microcomputer 16 via the input port. The microcomputer 16 includes a ROM in which a predetermined calculation program is stored, a RAM in which calculation results are stored, and a CPU for performing calculation processing, and calculates a sum and a difference between a transmission triangular modulation wave and a reception triangular modulation wave. Detects the following distance and the relative speed to the preceding vehicle. Then, the detected inter-vehicle distance and relative speed are sequentially changed to RA.
M.

On the other hand, the vehicle speed sensor 12 and the steering angle sensor 1
4 are provided at predetermined positions of the vehicle, and detect the speed and the steering angle of the own vehicle and output them to the microcomputer 16. The microcomputer 16 processes these detection signals and supplies a control signal to the driving device 18 to control the rotation of the transceiver 10. When the inter-vehicle distance from the preceding vehicle is less than a predetermined allowable value, an alarm device is issued. A warning signal is supplied to 20 to notify the driver.

A communication device 15 including an antenna and a data modulator / demodulator is provided at the front of the vehicle. This is a configuration for performing inter-vehicle communication such as vehicle speed.

Hereinafter, the operation of the microcomputer 16 will be described in detail with reference to the flowchart of FIG. First,
It is determined whether or not the own vehicle is following the preceding vehicle (S101). This determination is performed in two stages. First, it is determined whether or not a tracking system switch (not shown) is turned on and whether or not finite inter-vehicle distance data is supplied from the transceiver 10, which is a radar. . In this follow-up running mode, the vehicle speed of the own vehicle is controlled so that the inter-vehicle distance between the own vehicle and the preceding vehicle becomes substantially constant. When the own vehicle is following the preceding vehicle, the steering angle data of the preceding vehicle transmitted from the preceding vehicle via the communication device 15 is stored in the RAM of the microcomputer 16 (S102).

Next, the steering angle θHT of the preceding vehicle obtained by the inter-vehicle communication is compared with the steering angle θHR of the own vehicle obtained by the steering angle sensor 14 (S103). Specifically, the CPU calculates the difference between θHT and θHR stored in the RAM. Then, the absolute value of the difference is compared with a predetermined threshold value θTH stored in the ROM in advance (S104). When the preceding vehicle and the own vehicle have different steering angles, for example, the preceding vehicle enters a curved road and performs steering according to the curve curvature, while the own vehicle is still traveling on a straight road before the curved road. The difference value is equal to or greater than the threshold value when the vehicle is traveling or when the preceding vehicle changes lanes.

On the other hand, when both the preceding vehicle and the own vehicle are traveling on a straight road or a curved road, the steering angles of the two vehicles almost coincide with each other, and the difference value between them is less than the threshold value. In this case, the beam of the triangular modulation wave from the transmitter / receiver 10 is rotated by the steer logic from the own vehicle motion, and the preceding vehicle is captured (S105). The steering logic in the present embodiment is performed using the steering angle of the own vehicle, the inter-vehicle distance to the preceding vehicle, and the vehicle speed of the own vehicle. That is, first, the radius of curvature ρ of the curved road is calculated using the steering angle θHR
Ρ = (1 + K1 · V ² ) · K 2 / θHT, and the radar rotation angle θSL is obtained by using the curve curvature and the inter-vehicle distance L as θSL = sin ⁻¹ (L / 2ρ). The control signal is supplied to the device 18 so that the transceiver 1
Drive 0.

As described above, when the preceding vehicle and the own vehicle are steered at substantially the same steering angle, the preceding vehicle can be captured by the information obtained from the own vehicle motion. When the vehicle and the own vehicle have different steering angles, it is difficult to capture the preceding vehicle with the information obtained from the own vehicle motion.

Therefore, in the present embodiment, when the difference value is equal to or larger than the threshold value, the following processing is performed to catch the preceding vehicle. That is, in order to detect the cause of the difference value, it is first determined whether or not the preceding vehicle has changed lanes (S105). This determination can be made, for example, using the inter-vehicle distance to the preceding vehicle and the temporal change rate of the echo intensity obtained by the transceiver 10. In other words, when the echo intensity is significantly reduced even though the inter-vehicle distance is not largely changed, it can be determined that the preceding vehicle has changed lanes.
Of course, this determination may be made by analyzing the image of the preceding vehicle obtained by the CCD camera mounted on the own vehicle and determining whether the preceding vehicle has operated the direction indicator or transmitted from the preceding vehicle. The course change data may be received and obtained by the communication device 15.

If it is determined by these determination methods that the preceding vehicle has not changed course, then it is determined whether or not the own vehicle is located on a straight line (S106). In this determination, the steering angle of the own vehicle obtained by the steering angle sensor 14 is 0.
Can be determined based on whether or not within a predetermined range including If it is determined that the own vehicle is not on a straight line, that is, it is running on a curved road, the own vehicle is still on the curved road even though the preceding vehicle has already left the curved road and is running on a straight road. Means that the vehicle is traveling (near a curve exit).

In this case, in order to always direct the radar beam toward the preceding vehicle, the radar beam is driven at a predetermined rotation change rate (S107). FIG. 5 is a plan view for explaining the rotation change rate. Own vehicle is on point B on the curved track
, And the preceding vehicle is located at point A on a straight road. Radar rotation angle ShitaSL's own vehicle as described above steering angle θHT traveling a curve track, ShitaSL from the vehicle speed V and the inter-vehicle distance ^{L = sin -1 (L / 2ρ} ) ρ = (1 + K1 · V 2) · K2 / ΘHT. If the angle is maintained as it is, it is not possible to catch the preceding vehicle, so it is necessary to gradually return the turning angle of the radar. Since the time te required for the vehicle to exit the curved track is approximately te = Re / V (inter-vehicle distance L = Re), the radar beam is returned with the rotation change rate β as β = θSL / te. This makes it possible to always catch the preceding vehicle.

On the other hand, when the own vehicle is on a straight line, that is, when the preceding vehicle is already running on a curved road, but the own vehicle is still running on a straight road (curve entrance), It is necessary to know the curvature of the curve where the car is traveling. In this embodiment, therefore, the curvature is estimated using the steering angle data transmitted from the preceding vehicle (S10).
9). That is, the steering angle θHR of the preceding vehicle stored in the RAM is read, and the vehicle speed V and the relative speed VR of the own vehicle are read.
Calculating a preceding vehicle speed V0 from the preceding vehicle is to estimate the curvature of the curve track for running by ρT = (1 + K1 · V0 2) · K2 / θHR using these. Then, the rotation angle θSL θSL = sin ⁻¹ (L / 2ρt) is determined using the curvature. Since the time ti required for the vehicle to enter the curved lane is ti = L / V, the radar beam is gradually deflected so that the rotation change rate α becomes α = θSL / ti, and the preceding vehicle To capture.

Then, after such a radar beam turning is performed for a predetermined time (that is, a time until the own vehicle enters the curved road or the time when the own vehicle leaves the curved road) (S
110), again the difference value between the steering angle of the preceding vehicle and the own vehicle is compared with the threshold value (S111). If there is no change in the traveling state of the preceding vehicle, both the preceding vehicle and the own vehicle are traveling on a curved road or a straight road after the lapse of a predetermined time, so that the steering angles almost coincide with each other.
The process proceeds to the same steer logic as in No. 5, and the following of the preceding vehicle is continued (S112).

On the other hand, when the preceding vehicle changes lanes during a curved road, the steering angles of the preceding vehicle and the own vehicle do not match.
In this case, the preceding vehicle following flag is turned off, and the following vehicle is stopped following (S113).

As described above, in this embodiment, when the vehicle is at the entrance of a curve, the radar beam is gradually changed using the steering angle of the preceding vehicle, and when the vehicle is at the exit of the curve, the steering angle of the vehicle is used. By gradually returning the radar beam,
The preceding vehicle can be reliably captured.

[0025]

As described above, according to the on-vehicle radar device according to the present invention, the preceding vehicle can be reliably captured even at the entrance and exit of the curved road, so that the vehicle can follow the preceding vehicle smoothly. There are effects that can be performed.

[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 an operation flowchart of the embodiment.

FIG. 5 is an explanatory diagram of rotation change rate calculation of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Transceiver 12 Vehicle speed sensor 14 Steering angle sensor 15 Communication device 16 Microcomputer 18 Drive

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01S 13/93 G01S 17/93 G08G 1/16

Claims (1)

(57) [Claims] 1. A communication means for receiving steering angle data transmitted from a preceding vehicle; a radar for detecting a preceding vehicle; an inter-vehicle distance detecting means for detecting an inter-vehicle distance to the preceding vehicle; Speed detection means for detecting the vehicle speed of the own vehicle, steering angle detection means for detecting the steering angle of the own vehicle, and the steering angle of the preceding vehicle obtained by the communication means. Difference calculating means for calculating a difference from the steering angle of the vehicle, the steering angle of the preceding vehicle, the following distance, when the magnitude of the difference is a predetermined value or more and the own vehicle is not running on a curved road, The radar is turned on the basis of the relative speed and the vehicle speed to catch the preceding vehicle, and the steering angle of the own vehicle when the magnitude of the difference is equal to or larger than a predetermined value and the own vehicle is traveling on a curved road. , Based on the following distance, relative speed and vehicle speed Vehicle radar apparatus characterized by having a drive means for capturing a preceding vehicle by.