Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Automatic route guidance vehicle
Reexamination Certificate
2001-09-27
2003-09-09
Nguyen, Tan Q. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Automatic route guidance vehicle
C701S026000, C180S167000, C342S070000
Reexamination Certificate
active
06618653
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a motor vehicle position recognizing system for recognizing or detecting with high accuracy a position of a motor vehicle such as automobile, car, track or the like objects moving or traveling on a road on the basis of magnetic field intensities generated at predetermined positions on a road surface and detected by a magnetic field intensity detecting means mounted on the vehicle.
2. Description of Related Art
In recent years, there have been proposed and developed for practical applications a variety of motor vehicle position recognizing systems in which magnetic field generating means are laid on a road for generating or forming predetermined magnetic fields at predetermined positions on the road surface for thereby detecting with high accuracy the vehicle position on the basis of the magnetic field intensity detected by the magnetic field intensity detecting means mounted on the motor vehicle traveling on the road surface with a view to making it possible to realize an automatic steering control of the motor vehicle and a lane departure alarming function.
By way of example, the hitherto known or conventional motor vehicle position recognizing system disclosed in Japanese Patent Application Laid-Open Publication No. 206173/1998 (JP-A-10-206173) is comprised of magnetic field generating means or magnetic markers laid on the road surface at predetermined positions for generating or forming predetermined magnetic fields and a magnetic field intensity detecting means (magnetic sensor) mounted on a motor vehicle for detecting the magnetic field emanated from the magnetic markers, for thereby arithmetically determining the vehicle position on the basis of the magnetic field intensity detected by the magnetic sensor.
Further, the conventional motor vehicle position recognizing system mentioned above includes a vehicle position arithmetic means which incorporates therein a vehicle position arithmetic operation propriety decision means for making decision as to propriety of the arithmetic determination concerning the position of the motor vehicle so that the arithmetic operation for determining the motor vehicle position on the basis of the field intensity detected by the magnetic sensor is performed in dependence on the result of the decision made by the vehicle position arithmetic operation propriety decision means.
In addition, the conventional motor vehicle position recognizing system mentioned above includes a nonmagnetic field position determining means for determining nonmagnetic field position which is insusceptible to the influence of the magnetic sensor (e.g. mid or intermediate position between the magnetic markers) so that the magnetic field intensity detected by the magnetic sensor can be corrected by referencing the magnetic field intensities at the nonmagnetic field positions recorded in advance.
With the conventional motor vehicle position recognizing system described above, the magnetic field intensity can be determined without suffering the influence of the terrestrial magnetism and the magnetic field(s) emanated from the motor vehicle itself. Thus, the vehicle position can be detected or recognized with reasonable accuracy.
In this conjunction, it is however noted that the characteristics and the types of the magnetic markers may differ from one another. Besides, the height of the magnetic sensor mounted on the motor vehicle relative to the magnetic marker may undesirably change in dependence on the conditions of the road surface (e.g. roughness, unevenness, snowfall, etc.).
FIG. 7
is a block diagram showing generally and schematically a conventional motor vehicle position recognizing system such as disclosed, for example, in Japanese Patent Application Laid-Open Publication mentioned above.
Referring to
FIG. 7
, a magnetic field generating means implemented as a magnetic marker or markers
1
are laid on a road for the motor vehicles.
Parenthetically, only one magnetic marker
1
is representatively shown in the figure. It should however be appreciated that a plurality of the magnetic markers
1
may of course be laid on the road, for example, in the form of a marker row or rows.
In this conjunction, the magnetic markers
1
of a marker row laid at a center position on a lane may be arrayed such that the magnetic polarities of the magnetic markers change alternatively, e.g. in the order of N, S, N, S, . . . . On the other hand, in the marker row laid on the lane, being offset to the right from the center marker row by e.g. 1 m, the magnetic markers may be arrayed with a uniform polarity, e.g. in the sequence of N, N, N, N, . . . . Similarly, in the marker row laid with the offset to the left from the center marker row by e.g. 1 m, the magnetic markers may be arrayed with the opposite polarity, e.g. in the sequence of S, S, S, S . . . .
Installed on the motor vehicle running on the road surface on which the magnetic markers
1
are laid is a motor vehicle position recognizing apparatus
4
which is composed of magnetic sensors
2
and a vehicle-onboard detection unit
3
. The magnetic sensors
2
are disposed at positions opposite to the magnetic marker rows, respectively. The output signals of the magnetic sensors
2
are supplied to the vehicle-onboard detection unit
3
.
More specifically, a plurality of the vehicle-onboard magnetic sensors
2
are disposed in the transverse direction of the motor vehicle (i.e., in the direction orthogonal to the running or traveling direction), e.g. at right, center and left positions, respectively, as is illustrated in FIG.
7
.
Further, the motor vehicle is equipped with various types of sensors inclusive of a vehicle speed sensor
5
and others, wherein detection signals outputted from these sensors are inputted to the vehicle-onboard detection unit
3
as well.
The vehicle-onboard detection unit
3
is designed to determine arithmetically a transverse position Phr of the relevant motor vehicle on the basis of the output signals of the magnetic sensors
2
, the vehicle speed sensor
5
and others.
Next, by referring to
FIGS. 8A
,
8
B and
8
C, description will briefly be made of the operation of the conventional motor vehicle position recognizing system shown in FIG.
7
.
FIGS. 8A
,
8
B and
8
C are views for illustrating, respectively, the strength distribution of the output signal of the magnetic sensor
2
and intensities of a vertical magnetic field intensity signal (hereinafter also referred to as the vertical field intensity signal) and a horizontal magnetic field intensity signal (hereinafter also referred to as the horizontal field intensity signal) detected in correspondence to the position of the motor vehicle in the running or traveling direction in dependence on the positional relations between the magnetic sensors
2
and the magnetic markers
1
(i.e., positional deviation Ph of the motor vehicle in the transverse direction).
Each of the magnetic markers
1
laid on the road at predetermined positions generates or forms a magnetic field of a predetermined intensity on or above the road surface. Thus, the motor vehicle equipped with the motor vehicle position recognizing apparatus
4
moves through the magnetic fields mentioned above.
At that time, the plural onboard magnetic sensors
2
output the magnetic field intensity signals in response to the intensities of the magnetic fields generated by the magnetic markers
1
, respectively.
The vehicle-onboard detection unit
3
fetches the magnetic field intensity signals from the outputs of the magnetic sensors
2
while sampling the magnetic field intensity signals in dependence on the engine operation state detection signals derived from the outputs of the vehicle speed sensor
5
and others.
The vehicle-onboard detection unit
3
is so designed as to detect the magnetic field intensity distribution in the magnetic field space to thereby determine arithmetically the position Phr of the motor vehicle in the transverse direction on the basis of the spatial field intensity d
Mitsubishi Denki & Kabushiki Kaisha
Nguyen Tan Q.
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