JPH10132920A - On-vehicle radar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an on-vehicle radar device which can detect deviation of an optical axis regardless of the number of installed radar heads. SOLUTION: An on-vehicle radar device is equipped with an attached angle monitoring component 1, 11, 12, 14 which monitor deviation from a reference value of an attachment angle between a radar head such as a laser-radar head 3 and the vehicle. If the deviation is a prescribed value or more, the components inform a driver of that. The radar device is preferably equipped with an display 13 which displays deviation of the attachment angle under monitoring.

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 used in a vehicle collision warning system and the like, and more particularly to an on-vehicle radar device having a function of monitoring an angle of attachment to a vehicle. .

[0002]

2. Description of the Related Art Hitherto, a collision warning system using a radar apparatus for transmitting and receiving a beam such as a laser beam, an electromagnetic wave or a sound wave has been developed. This collision warning system
When using a laser radar, the inter-vehicle distance to the preceding vehicle is detected from the required propagation time required for the emitted laser beam to travel back and forth to the preceding vehicle, which is a reflector. When the distance between the vehicles is less than the safe inter-vehicle distance calculated from the above, the driver is warned by a buzzer or the like of a danger of a collision with the preceding vehicle.

[0003] In the radar apparatus of the above-mentioned conventional collision warning system, how to adjust the optical axis of a radar head for transmitting and receiving a beam to an optimum state has become a technically important issue. In particular, the adjustment of the optical axis of a laser head for transmitting and receiving a laser beam having a sharp directivity is an important technical problem, which is described in Japanese Utility Model Publication No.
Various proposals have been made in 7843 and the like.

[0004] In parallel with the above-mentioned problem of the optical axis adjustment, it is also an important technical problem to detect the deviation of the adjusted optical axis during use and to return the optical axis to the original state. This is because not only the vibration and impact accompanying the running of the vehicle, but also the misalignment of the optical axis due to mischief of a passenger such as a child can be considered. However, there are few proposals for detecting the deviation of the optical axis. Typically, two laser heads are installed adjacent to each other, and an auxiliary light transmission / reception path is formed between the two laser heads. Japanese Patent Application Laid-Open No. 63-163600 proposes a method for detecting the occurrence of a positional deviation, and thus an optical axis deviation.

[0005]

The method of detecting an optical axis shift proposed in the above-mentioned patent publication is considered effective when a plurality of laser heads are installed on the back side of a bumper or the like. However, such a laser head is mounted on a dashboard in a vehicle compartment where there is not much room in space.
This detection method cannot be applied when only a stand is installed.
Accordingly, it is an object of the present invention to provide an on-vehicle radar device having a function of detecting an optical axis shift applicable regardless of the number of laser heads installed.

[0006]

The on-vehicle radar device according to the present invention monitors the amount of deviation of a mounting angle of a radar head from a vehicle from a reference value (such as a value immediately after optical axis adjustment), and monitors the deviation amount. A mounting angle monitoring unit and a display unit are provided for notifying the driver when the value exceeds a predetermined value or displaying the amount of deviation being monitored. Another on-vehicle radar apparatus according to the present invention includes a mounting angle control / monitoring means for monitoring a change amount of a mounting angle of a radar head to a vehicle and automatically controlling the mounting angle in a direction to reduce the change amount. ing.

[0007] According to a preferred embodiment of the present invention, the mounting angle monitoring means monitors the amount of deviation of the mounting angle separately for a horizontal component and a vertical component, and further includes means for displaying the amount of deviation being monitored. Preferably, the radar device is configured to stop the distance detection function of the radar device when the amount of deviation during monitoring becomes equal to or more than a predetermined value.

[0008]

FIG. 1 is a functional block diagram showing the configuration of a vehicle collision warning system including an on-board laser radar device according to an embodiment of the present invention. Is a laser radar head, 4 is an input interface unit, 5 is a data memory, 6 is an alarm generator, 7
Is a key input unit. Further, 10 is a rotation holding mechanism of the laser radar head, 11 is a horizontal angle detection unit, 12 is a vertical angle detection unit, 13 is a deviation angle display unit, and 14 is a warning light.

The laser radar head 3 is installed on a dashboard or the like in a vehicle compartment, and emits a pulsed laser beam from a light transmitting unit toward the front of the host vehicle. The emitted laser beam is reflected by a reflector such as a preceding vehicle existing in front of the host vehicle and received by a light receiving unit of the laser radar head 3. The transmission and reception of the laser pulse is performed within an appropriate angle range in front of the host vehicle based on mechanical scanning of a reflecting mirror performed in the laser radar head 3 and the like.

The inter-vehicle distance detection unit 2 calculates the propagation distance of the laser beam from the propagation time required for the laser radar head 3 to transmit the laser beam and receive the reflected beam, ie, the distance from the preceding vehicle. Detect inter-vehicle distance.
The data processor 1 receives the inter-vehicle distance from the preceding vehicle detected by the inter-vehicle distance detection unit 2 from the inter-vehicle distance detection unit 2 and stores it in the data memory 5. Further, the data processor 1 includes various data indicating a running state of the vehicle such as a vehicle speed, an acceleration, and a steering angle, an on / off signal of a light indicating a daytime / nighttime zone, and a wiper indicating a fine weather / rainy weather. A driving environment signal including an ON / OFF signal of the vehicle is received from various sensors and devices through the input interface unit 4 and stored in the data memory 5.

The data processor 1 is prepared in advance based on a running algorithm such as the running speed of the own vehicle based on an appropriate algorithm and registered in the data memory 5 in parallel with the process of storing the various data in the data memory 5. The safe inter-vehicle distance from the preceding vehicle is read from the data memory 5 and compared with the safe inter-vehicle distance and the actual inter-vehicle distance detected by the inter-vehicle distance detection unit 2. When the actual inter-vehicle distance becomes smaller than the safe inter-vehicle distance, the data processor 1 issues a warning about a danger of a rear-end collision to the driver via the warning generation unit 6.

In the functional block diagram of FIG. 1, a rotation holding mechanism 10, a horizontal angle detecting unit 11, a vertical angle detecting unit 12, a deviation angle displaying unit 13, and a warning light 14 of the laser radar head 3 are shown separately for each function. Are physically combined while maintaining the relationship as shown in the exploded perspective view of FIG. The rotation holding mechanism 10 of the laser radar head holds the laser radar head 3 via a rotation holding mechanism capable of adjusting the angle in each of the horizontal direction and the vertical direction, and also holds the rotation holding mechanism in the horizontal direction and the vertical direction. A horizontal angle detection unit 11 and a vertical angle detection unit 12 are each formed by a well-known rotary encoder and potentiometer.

Although not shown for simplicity, each of the horizontal and vertical rotation holding mechanisms is naturally provided with a well-known lock for the rotation angle and a release mechanism therefor. In the unlocked state for the rotation angle,
The optical axis of the laser radar head 3 is adjusted in each of the horizontal direction and the vertical direction by using a known appropriate method. When the optical axis adjustment is completed, the lock is performed, and the horizontal and horizontal angles are adjusted. The value is fixed at the end of the optical axis adjustment.

The laser radar head 3 held by the rotation holding mechanism 10 is accommodated in a rectangular parallelepiped housing, and a light transmitting lens TL is provided on the side of the housing facing the front of the vehicle. And a light receiving lens RL. A displacement angle display section 13 composed of a liquid crystal panel and a warning light 14 are arranged on the rear side of the housing facing the driver.

When the above-mentioned adjustment of the optical axis and the locking of the rotation holding mechanism are completed, the vehicle maintenance / inspection operator or driver performs a key input for notifying the end from the key input unit 7. The data processor 1 includes an input / output interface unit 4
When the key input is received via the
1 and the vertical angle detection unit 12 read the detected horizontal angle and vertical angle via the input / output interface unit 4 and store them in the data memory 5 as initial values or reference values of the horizontal angle and vertical angle, respectively.

The rotation angle of the rotation holding mechanism 10 fixed at the end of the optical axis adjustment in this manner is changed by the vibration or impact applied by the running of the vehicle or the mischief of the infant.
A gap may occur. The data processor 1 performs the detection of such an angle deviation at a constant period while the vehicle is running. The method of detecting the deviation amount will be described with reference to the flowchart of FIG.

When the data processor 1 starts the detection processing, it reads the initial values of the horizontal angle and the vertical angle from the data memory 5 and sets them in a built-in register (step 31).
Subsequently, the horizontal angle and the vertical angle being detected are read from the horizontal angle detector 11 and the vertical angle detector 12 via the input / output unit 4 (step 32). Next, the data processor 1 calculates each initial value (reference value) from the horizontal and vertical angles being detected.
Is subtracted to calculate a horizontal angle deviation amount (horizontal deviation angle Eh) and a horizontal angle deviation amount (vertical deviation angle Ev) (step 33). The data is transferred to the display unit 13 and is displayed there (step 34).

The data processor 1 determines whether or not the calculated horizontal deviation angle Eh is less than a predetermined threshold value E1 (step 35). If this is less than the threshold value E1, then the calculated vertical deviation angle Ev is determined. Is smaller than a predetermined threshold value E2 (step 36). When the data processor 1 detects that either the horizontal deviation angle or the vertical deviation angle is equal to or larger than a predetermined threshold, the data processor 1 determines whether or not the warning lamp 14 is already lit (step 37). If not, the warning light 14 is illuminated in amber to notify the driver of the fact, and the transmission of the laser beam from the laser head 3 is stopped to stop the operation of detecting the inter-vehicle distance as a radar. (Step 38) After this,
It returns to step 32.

When the driver notices abnormality of the radar device by turning on the warning light 14 or the like, the driver temporarily releases or relaxes the lock mechanism for fixing the angle of the holding mechanism, and sets the deviation angle displayed on the deviation angle display section 13 to zero. After adjusting the horizontal angle and the vertical angle, lock again. When the data processor 1 detects in steps 35 and 36 that the horizontal deviation angle Eh and the vertical deviation angle Ev have become smaller than the respective threshold values E1 and E2, it is determined whether the warning lamp 14 is on. Then, if it is being turned on, the light is turned off and the laser head 3 is restarted to resume the radar distance detection operation (step 40).

FIG. 4 is a functional block diagram showing a configuration of a vehicle collision warning system including a vehicle-mounted laser radar device according to another embodiment of the present invention. The on-vehicle laser radar device of this embodiment differs from the on-vehicle laser radar device described with reference to FIG. 1 in that a horizontal angle detection / adjustment unit 21 and a vertical angle detection / adjustment unit 22 are a rotary encoder or a potentiometer. In addition to the angle detection function of the present invention, an automatic correction function of a deviation angle by a pulse motor or the like is provided.

That is, as shown in the flowchart of FIG. 5, in step 38, the warning lamp 14 is turned on,
After the radar operation is stopped, in step 41, the deviation angle detected by the horizontal angle detection / adjustment unit 21 or the vertical angle detection / adjustment unit 22 is reduced by rotating a pulse motor or the like so as to approach zero. Automatic adjustment is performed. In the flowchart of FIG. 5, steps denoted by the same reference numerals as the steps of the flowchart of FIG. 3 are the same as the corresponding steps already described with reference to FIG. 3, and the duplicate description thereof will be omitted.

The flowchart of FIG. 5 illustrates only the main part of the processing executed by the data processor 1, and actually, more complicated processing is added. For example,
When the deviation angle is too large, automatic adjustment cannot be performed.Steps to determine whether adjustment is possible.If adjustment is not possible, a specific error code is displayed. A step of notifying is added as needed.

As described above, in the embodiment shown in FIG. 1, a configuration in which the warning lamp is turned on when the deviation angle becomes a predetermined value or more is exemplified. However, when the deviation angle is equal to or larger than a predetermined value, other lamps such as turning off a lamp displaying a normal operation state, sounding a buzzer, and displaying a message to that effect on an inter-vehicle distance display panel, etc. A configuration can also be employed. Alternatively, a simple configuration may be adopted in which the detected deviation amount is simply displayed without generating an alarm even if the deviation amount increases, and the timing of returning the angle to the reference value is left to the driver.

Also, the configuration in which the deviation angle is displayed on the back surface of the laser head has been exemplified. However, the deviation angle is displayed on another appropriate display panel related to the laser device or the alarm system, such as a display panel of the detected inter-vehicle distance. It can also be configured.

Further, the configuration has been exemplified in which the operation of the radar is automatically stopped when the deviation amount exceeds the threshold value. However, when the threshold value is set to a small value, the radar operation may be continued without stopping.

Further, the case of a laser radar device for transmitting and receiving a laser beam has been described as an example, but the present invention can be applied to other types of radar devices for transmitting and receiving a radio wave or a sound wave beam.

[0027]

As described above in detail, the on-vehicle radar device of the present invention notifies the driver when the amount of deviation of the mounting angle of the radar head from the reference vehicle exceeds a predetermined value. Display the amount of deviation being monitored,
Since the automatic adjustment is performed in the direction in which the shift amount is reduced, the optical axis shift can be detected regardless of the number of laser heads installed.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a configuration of a vehicle-mounted collision warning system including a laser radar device according to one embodiment of the present invention.

FIG. 2 shows a laser head 3, a rotation holding mechanism 10 in FIG.
FIG. 3 is an exploded perspective view illustrating a physical combination state of a horizontal angle detection unit 11, a vertical angle detection unit 12, a deviation angle display unit 13, and a warning light 14.

FIG. 3 is a flowchart for explaining the content of a deviation angle detection process executed by a data processor 1 in the embodiment.

FIG. 4 is a functional block diagram showing a configuration of a vehicle-mounted collision warning system including a laser radar device according to another embodiment of the present invention.

FIG. 5 is a flowchart for explaining the content of a deviation angle detection / adjustment process executed by the data processor 1 in the other embodiment.

[Explanation of symbols]

 1 Data Processor 2 Inter-Vehicle Distance Detector 3 Laser Head 10, 20 Rotation Holding Mechanism 11 Horizontal Angle Detector 12 Vertical Angle Detector 13 Deflection Angle Display 14 Warning Light 21 Horizontal Angle Detector / Adjuster 22 Vertical Angle Detector / Adjuster

Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01S 17/93 G01S 17/88 A

Claims (9)

[Claims] A radar head for transmitting a beam and receiving a reflected beam of the beam from a reflector, and a function of detecting a distance to the reflector based on a time from transmission to reception of the beam by the radar head. An on-vehicle radar device comprising: a mounting angle monitoring unit that monitors a deviation amount of a mounting angle of the radar head to a vehicle from a reference value and, when the deviation amount is equal to or greater than a predetermined value, notifies a driver of the deviation amount. An on-vehicle radar device comprising: 2. The on-vehicle radar device according to claim 1, wherein the attachment angle monitoring means further includes means for displaying a deviation amount of the attachment angle being monitored. 3. A radar head for transmitting a beam and receiving a reflected beam of the beam from a reflector, and a function of detecting a distance to the reflector based on a time from transmission to reception of the beam by the radar head. An on-vehicle radar device comprising: means for detecting and displaying a deviation amount of a mounting angle of the radar head to a vehicle from a reference value, and displaying the detected amount. 4. The apparatus according to claim 1, wherein said mounting angle monitoring means monitors, detects, or displays a deviation amount of said mounting angle separately for a horizontal component and a vertical component. In-vehicle radar device. 5. The apparatus according to claim 1, wherein the mounting angle monitoring means stops the distance detection operation by the radar device when a deviation amount of the mounting angle becomes a predetermined value or more. In-vehicle radar device. 6. A radar head for transmitting a beam and receiving a reflected beam of the beam from a reflector, and a function of detecting a distance to the reflector based on a time from transmission to reception of the beam by the radar head. An on-vehicle radar device comprising: a mounting angle monitoring / control means for monitoring a deviation amount of a mounting angle of the radar head to a vehicle from a reference value and changing the mounting angle in a direction to reduce the deviation amount. An in-vehicle radar device characterized in that: 7. The on-vehicle radar device according to claim 6, wherein the mounting angle monitoring / control means changes the mounting angle when the amount of deviation during the monitoring becomes a predetermined value or more. 8. The on-vehicle radar device according to claim 6, wherein the mounting angle monitoring means monitors the amount of deviation of the mounting angle separately for a horizontal component and a vertical component. 9. The on-vehicle radar device according to claim 1, wherein the radar head is a laser radar head that transmits and receives a laser beam.