JPS6326590A - Measuring instrument for vehicle-to-vehicle distance - Google Patents

Abstract

PURPOSE:To securely detect a precedent vehicle even during a run on a curved road by detecting the precedent vehicle on condition that the steering angle when the precedent vehicle runs at the current position of a following vehicle is equal to the current steering angle of the following vehicle. CONSTITUTION:A vehicle speed (v) and a steering angle delta detected by a vehicle speed sensor 12 and a steering angle sensor 14 are supplied to a processing circuit 16. A radar device 10 is equipped with a light transmitter 24 which emits a vertically flat radar beam 102 to in front of a vehicle in its running direction and a light receiver 26 which receives its reflected wave 104. The light transmitter 24 obtains the pulsating laser beam 102 synchronized with the clock signal of a clock generator 28 and the light reception signal of the light receiver 26 is supplied to a distance detecting circuit 32 through an amplifier 30. The circuit 32 finds the distance to a body present in front of the vehicle from the delay time from the input of the clock signal of the generator 28 to the input of the light reception signal of the light receiver 26. A scanning device 34 scans the beam 102 of the light transmitter 24 in a horizontal plane in the width direction of the vehicle and supplies its scanning angle to the circuit 16 as the azimuth of the body which is present in the running direction to the this vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for measuring inter-vehicle distance using radar.

(Prior Art) This type of device is known from Japanese Patent Publication No. 51-7892, and an example thereof is shown in FIG.

In the figure, radar waves such as radio waves, light, and ultrasonic waves are emitted from a radar device 10 toward the front in the vehicle traveling direction, and reflected waves thereof are received.

The vehicle speed (vehicle speed) and steering angle are detected by a vehicle speed sensor 12 and a steering angle sensor 14, respectively, and these detection signals are supplied to a processing circuit 16 together with a measurement signal from the radar device 10.

The processing circuit 16 detects the inter-vehicle distance based on the measurement signal from the radar device 10, and the radar drive device 18 is controlled by the processing circuit 16.

The radar device 10 is rotated in a horizontal plane by the radar drive device 18, so that the radar waves are directed in a direction according to the vehicle steering angle detected by the steering angle sensor 14.

As a result, as shown in FIG. 3, when the host vehicle 20 is traveling on a curved road, radar waves 100 are emitted toward the preceding vehicle 22 in accordance with its steering, and the preceding vehicle 22 can be detected while traveling on the curved road. It becomes possible to extend the distance.

(Both points are to be solved by the invention) However, in this conventional device, radar waves of 100
Since the direction is controlled according to the vehicle steering, the preceding vehicle 22
When the own vehicle 20 enters a curved road after a certain delay, the radar waves 100 are not directionally controlled in the direction of the preceding vehicle 22, which causes a problem that it becomes difficult to detect the preceding vehicle 22.

The present invention has been made in view of the above-mentioned conventional problems,
The purpose is to provide an inter-vehicle distance measuring device that can reliably detect a preceding vehicle even when driving on a curved road.

(Means for Solving the Problems) In order to achieve the above object, an apparatus according to the present invention is configured as shown in FIG.

In the figure, radar means a emits radar waves that spread toward the interior of the vehicle, and the distance to an object in front of the vehicle in the direction of travel and the direction of the object relative to the vehicle are detected.

The steering angle of the vehicle at the position of the object is predicted by the steering angle prediction means based on the detected distance and direction.

Further, the predicted steering angle is sequentially written by the steering angle storage means C.

Further, the traveling speed of the own vehicle is detected by the vehicle speed detecting means d, and the time required for the own vehicle to travel the detected distance is calculated by the traveling time calculating means e from the detected speed.

The steering angle reading means f reads out the predicted steering angle at the current position of the vehicle from the steering angle storage means C based on the calculated travel time.

Further, the steering angle detecting means q is about to output the steering angle of the own vehicle, and the following distance determining means indicates that an object whose read steering angle approximately matches the current detected steering angle is the vehicle ahead of the own vehicle. The detected distance for the object is determined as the inter-vehicle distance.

(Function) In the present invention, radar waves that spread in the vehicle width direction are emitted toward the front of the vehicle, and the reflected waves detect the distance to an object in front of the vehicle in the traveling direction and the orientation with respect to the own vehicle.

The vehicle steering angle at the position of the object is always determined from the detected distance and direction, and these steering angles are sequentially stored.

Further, the time required for the host vehicle to travel the detected distance at the current vehicle speed is determined, and the stored steering angle at the host vehicle's current position is read out using this calculation time.

When the vehicle steering angle substantially matches the current steering angle of the own vehicle, the object is determined to be the preceding vehicle, and the detected distance to this object is determined as the inter-vehicle distance to the preceding vehicle.

(Embodiments) Hereinafter, preferred embodiments of the apparatus according to the present invention will be described based on the drawings.

In FIG. 4, the vehicle speed V and steering angle δ detected by the vehicle speed sensor 12 and the steering angle sensor 14 are provided to a processing circuit 16, and the processing circuit 16 is constituted by a microcomputer.

Furthermore, the radar device 10 is of a laser type, so the radar device 10 includes a light transmitter 24 that emits a vertically flat laser beam 102 forward in the vehicle running direction, and a light receiver 26 that receives the reflected wave 104. It is provided.

A pulsed laser beam 102 synchronized with a clock signal from a clock generator 28 is obtained from the light transmitter 24, and a light reception signal from the light receiver 26 is given to a distance detection circuit 32 via an amplifier 30.

The distance detection circuit 32 is also given a clock signal from the clock generator 28, and the distance detection circuit 30 has a delay from when the clock signal from the clock generator 32 is input until when the light reception signal from the light receiver 26 is input. The distance to the object in front of the vehicle is determined by the time td.

The laser beam 1 of the light transmitter 24 is then scanned by the scanning device @34.
02 is scanned in the vehicle width direction within a horizontal plane, and the scanning angle θ is given to the processing circuit 16 as the orientation of the object in front of the vehicle 20 in the traveling direction.

Note that the scanning angle θ of the laser beam 102 is limited to the deflection angle θR on the right side of the vehicle and to the deflection angle OL on the left side, and the viewing angle φ of the receiver 26 is limited to the maximum deflection angle (=θR + θL). It is considered to be sufficiently spacious.

As described above, the radar waves 100 that spread in the vehicle width direction are emitted from the radar device 1.0 to the front in the traveling direction of the host vehicle 20, and in the radar device 10, the radar waves 100 are transmitted from the host vehicle 20 to an object in front of the host vehicle 20 in the travel direction. distance! and the orientation θ of the object relative to the own vehicle 20.

And those detection distances! , azimuth θ, vehicle speed 2, and steering angle δ, the processing circuit 16 performs the processing shown in FIG.

In the figure, in the first step 200, the radar device 1
The distance mz and azimuth θ detected at 0, the vehicle speed V detected by the vehicle speed sensor 12, and the steering angle δ detected by the steering angle sensor 14 are read.

Then, in the next step 202, the vehicle steering angle δS at the object position is the detected distance! and the orientation θ.

The predictive effect is explained with reference to FIG. 6, in which the preceding vehicle 22 is traveling on a curved road with a curvature R.

Then, the laser beam 10 is directed toward the front direction of the own vehicle 20.
2 is the deflection angle θ, the preceding vehicle 22 is detected as an object in front of the host vehicle 20, and the host vehicle 20
The radar device 10 detects a short distance m from the vehicle 22 to the preceding vehicle 22.

Here, between the curvature R1, the deflection angle θ, and the distance l, g/2=
The relationship Rs i nθ is established, and the curvature R is a modification of the above equation R=, g/
2s i nθ, and when the vehicle travels on a curved road with a curvature R, the curvature R and the vehicle steering angle δ are expressed as δ=f(1/R>
Since the relationship ΦK·1/R ゛ holds, in this embodiment, the vehicle steering angle -δS is estimated using the formula “δs=f (2S inθ/ri).

Once the vehicle steering angle .delta.S is estimated in this manner, it is stored in step 204. Therefore, the vehicle steering angle .delta.S is estimated and stored one after another each time the process shown in FIG. 5 is performed.

Then, in step 206, the time Δt required for the host vehicle 20 to travel the detected distance l is determined from the detected speed ■, and its calculation is expressed by the following equation.

Δt =, g/v Furthermore, in step 208, the predicted steering angle δS at the current position of the own vehicle 20 is read out using the calculated travel time Δt.

In the next step 210, the predicted steering angle δS read out in step 208 is determined as the current detected steering angle δ of the host vehicle 20.
It is determined whether or not they substantially match. If it is confirmed that the two substantially match, the process proceeds to step 212, and if not, the process proceeds to step 214.

In step 2]2, it is determined that the object whose steering angle δS is predicted is the vehicle preceding the own vehicle, and the detected path for the object is output as the inter-vehicle distance.

Further, in step 212, it is determined that there is no preceding vehicle ahead of the own vehicle 20.

When these steps 212 and 214 are processed,
Finally, in step 216, the timer counter is incremented, and thereafter the processing from step 200 onwards is repeated.

As understood from the above explanation, the laser beam 102
is scanned, the processing circuit 16 detects the own vehicle 20.
A plurality of objects are detected in front of (Step 200>
.

Then, in the processing circuit 16, when each forward object is a preceding vehicle, the current steering angle δ of all preceding vehicles at those positions is determined.
S are constantly estimated, and these steering angles δS are sequentially stored each time they are estimated. (Steps 202 and 204) Furthermore, the estimated steering angle δS at the time when the preceding vehicles 22 would have passed the current position of the host vehicle 20 is read out (Step 208), and An object in front of which the steering angle δS is estimated to be approximately equal to the steering angle δ is detected as the preceding vehicle 22, and its detected distance l is determined and output as the inter-vehicle distance (steps 210 and 212).

As explained above, according to this embodiment, when the object in front of the own vehicle 20 is the preceding vehicle 22, the steering angle δS when the preceding vehicle 22 travels at the current position of the own vehicle 20 is Since the preceding vehicle 22 is detected on the assumption that the current steering angle δ matches the current steering angle δ, the preceding vehicle 22 can be reliably detected even when traveling on a curved road.

(Effects) As explained above, according to the present invention, an object in front of the own vehicle is detected using radar waves spreading in the vehicle width direction, and the current steering of the preceding vehicle at that position is performed by detecting an object in front of the own vehicle as the preceding vehicle. The angle δS is constantly estimated and stored sequentially for each estimation, and the estimated steering angle at the time when the preceding vehicle would have passed the current position of the own vehicle is read out, and the steering angle is approximately equal to the current steering angle of the own vehicle. Since the vehicle ahead is determined to be the preceding vehicle, it is possible to reliably detect the preceding vehicle even when driving on a curved road.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to claims, FIG. 2 is an explanatory diagram of the configuration of a conventional device, FIG. 3 is an explanatory diagram of the operation of the conventional device, FIG. 4 is a block diagram showing a preferred embodiment of the device according to the present invention, and FIG. 5 is a flowchart for explaining the processing procedure of the processing circuit in the embodiment of FIG. 4, and FIG. 6 is an explanatory diagram of the operation of the embodiment of FIG. 4. 10...Radar device 12...Vehicle speed sensor 14...Steering angle sensor 16...E in the processing circuit frame Figure 2 Figure 5 @ Figure 6

Claims (1)

[Claims] (1) Radar means that detects the distance from the own vehicle to an object in front of the own vehicle and the direction of the object relative to the own vehicle by emitting radar waves that spread in the vehicle width direction forward in the direction of travel of the own vehicle; , a steering angle prediction means for predicting the vehicle steering angle at the position of the object based on the detected distance and direction; a steering angle storage means for sequentially writing the predicted steering angle; and a vehicle speed detection means for detecting the traveling speed of the host vehicle. A travel time calculation means for determining the time required for the host vehicle to travel the detected distance based on the detected speed; a steering angle reading means for reading out a predicted steering angle at the current position of the host vehicle from the steering angle storage means based on the calculated travel time; a steering angle detection means for detecting a steering angle; and determining that an object for which a read steering angle substantially matching the currently detected steering angle is predicted to be a preceding vehicle of the host vehicle, and determining a detected distance of the object as an inter-vehicle distance. An inter-vehicle distance measuring device comprising: inter-vehicle distance determining means for determining an inter-vehicle distance.