Communications: directive radio wave systems and devices (e.g. – Return signal controls external device – Radar mounted on and controls land vehicle
Reexamination Certificate
2002-10-22
2004-10-26
Pihulic, Daniel (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Return signal controls external device
Radar mounted on and controls land vehicle
C342S072000
Reexamination Certificate
active
06809680
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an apparatus of detecting an obstacle of a vehicle such as an unmanned vehicle.
2. Description of the Related Art
An unmanned vehicle such as an unmanned dump truck operated in a wide site such as a quarrying site or a mine, automatically detects an obstacle in front of the vehicle and is automatically controlled to run based on a result of the detection. In this case, an unmanned vehicle such as an unmanned dump truck is generally wide in the vehicle width, a width of a running road therefor is also wide and therefore, in an obstacle detecting apparatus mounted on the unmanned vehicle, there is requested a function capable of catching an obstacle in a wide detection area.
As an obstacle detecting apparatus, there have conventionally known various kinds of radars such as an optical laser, a millimeter wave radar, and a visual sensor.
The radar is provided with an advantage of high accuracy and is preferable for mounting on an unmanned vehicle. In mounting the radar on the unmanned vehicle, there are various systems for covering the wide detection area as shown by items 1), 2), and 3), described below.
1) Fixed Scanning Radar System:
According to the system, as shown by FIG.
11
(
a
), a radar
2
is mounted on an unmanned vehicle
1
and radar beam
3
is scanned at high speed in a left and right direction in a range of about ±10° to thereby detect an obstacle
60
on a running road
50
.
2) Rotary Radar System:
According to the system, as shown by FIG.
11
(
b
), the radar
2
is mounted on the unmanned vehicle
1
and the radar beam
3
is rotated by 360° centering on the unmanned vehicle
1
to thereby detect the obstacle
60
on the running road
50
.
3) Pivoting Scanning Radar System:
According to the system, as shown by FIG.
11
(
c
), the radar
2
is mounted on the unmanned vehicle
1
via a pivoting base, the radar beam
3
is scanned at high speed in the left and right direction in a range of about ±10° and the radar beam
3
is pivoted by pivoting the pivoting base at low speed to thereby detect the obstacle
60
on the running road
50
.
An absolute position of the obstacle
60
can be measured by measuring an azimuth angle (scanning angle) of the radar beam
3
and a distance from the radar
2
to the obstacle
60
and based on measured values of these and the position and the azimuth angle of the unmanned vehicle
1
. Further, in the case of the pivoting scanning radar system of the above-described item 3), it is necessary to measure the absolute position of the obstacle
60
by measuring a pivoting angle of the pivoting base.
Further, there is also known a technology combined with the above-described items 1) and 3). For example, according to JP-A-4-163250, there is described invention with regard to a rear view sensor of a general automobile combining the fixed radar system of item 1) and the pivoting radar system of item 3) and the pivoting radar is pivoted in a direction of the obstacle caught by the fixed radar to thereby further catch the obstacle by the pivoting radar.
Further, in U.S. Pat. No. 5,612,883, there is described invention changing a scanning range in a pivoting scanning radar system.
Further, according to the literature, there is described invention successively measuring absolute positions of respective objects detected by radar beam to thereby determine whether the respective objects are the same obstacle.
When the fixed scanning radar system of FIG.
11
(
a
) is adopted, although accuracy in measuring the azimuth angle of the radar beam
3
is excellent and the obstacle
60
on a running road having a small curve can be detected, since a scanning area of the radar beam
3
is narrow, dead angle is present at a cross point and a sharp curve and there is a concern of overlooking the obstacle
60
.
Further, when the rotary radar system of FIG.
11
(
b
) is adopted, the radar beam
3
is rotated by 360° and therefore, there is not dead angle, however, since a detection period is long, it is wasteful to only detect the obstacle
60
on the front side and a considerable period of time is required for catching the obstacle
60
. Particularly, when the unmanned vehicle
1
is running at high speed (50 km/h), a considerable distance may be run until detecting the front obstacle
60
and there is a concern of interfering with the obstacle
60
.
When the pivoting scanning radar system of FIG.
11
(
c
) is adopted, there is not the dead angle and also the detection period is short and therefore, the system covers drawbacks of the fixed scanning radar system and the rotary radar system.
However, in order to measure the absolute position of the obstacle
60
, not only the azimuth angle (scanning angle) of the radar beam
3
and the azimuth angle of the unmanned vehicle but also a pivoting angle of the pivoting base must be measured and measurement errors of the angles are accumulated to thereby enlarge measurement error of the position of the obstacle. Since accuracy of the angles are poor in this way, the obstacle
60
at outside of the running road
50
is liable to be detected erroneously as the obstacle
60
in the running road
50
.
The invention has been carried out in view of the actual situation and it is a problem to be resolved to eliminate the dead angle, to be able to shorten the detection period and to reduce erroneous detection of the obstacle in detecting the obstacle of the vehicle.
Now, as described above, according to U.S. Pat. No. 5,612,833, in order to determine the same obstacle, the absolute positions of the respective objects are successively measured.
However, when the absolute positions of the objects are successively measured, the operational processing becomes complicated.
Hence, according to the invention, it is a problem to be resolved to be able to determine the same obstacle without carrying out the complicated operational processing.
SUMMARY OF THE INVENTION
According to a first aspect of the invention, there is provided an obstacle detecting apparatus of a vehicle for detecting an obstacle of a vehicle by using a radar, the obstacle detecting apparatus comprising a fixed radar fixed to the vehicle, and a pivoting radar pivotable relative to the vehicle, wherein the pivoting radar is pivoted in a direction in accordance with a progressing direction of the vehicle such that radar beam is emitted in the direction in accordance with the progressing direction of the vehicle.
According to the first aspect of the invention, as shown by
FIG. 6
, when a vehicle
1
runs on a running road
50
, by pivoting a pivoting radar
24
in a direction in accordance with a progressing direction of the vehicle
1
, a total or a portion of a detection range
3
B of the pivoting radar
24
can be made to be outside of a detection range
3
A of fixed radars
21
through
23
. Therefore, an obstacle
60
in a range outside of the detection range of the fixed radars
21
through
23
can be detected by the pivoting radar
24
.
Therefore, in detecting the obstacle
60
of the vehicle
1
, dead angle can be eliminated. That is, since the fixed radars
21
through
23
and the pivoting radar
24
are provided, the detection range of the obstacle can be covered with respect to both a linear road or the running road
50
having a large radius of curvature shown in FIG.
7
and the running road
50
having a small radius of curvature such as a cross point or a sharp curve shown in FIG.
6
. Further, since both of the fixed radars
21
through
23
and the pivoting radar
24
are used, a detection period can be shortened. Further, since the pivoting radar
24
is used along with the fixed radars
21
through
23
, erroneous detection of the obstacle can be reduced.
According to a second aspect of the invention, there is provided an obstacle detecting apparatus of a vehicle for detecting an obstacle of a vehicle by using a radar, the obstacle detecting apparatus comprising a fixed radar fixed to the vehicle, and a pivoting radar pivotable relative to the
Komatsu Ltd.
Pihulic Daniel
Varndell & Varndell PLLC
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