Data processing: vehicles – navigation – and relative location – Relative location – Collision avoidance
Reexamination Certificate
2002-06-03
2004-11-30
Louis-Jacques, Jacques H. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Relative location
Collision avoidance
C701S096000, C701S300000, C180S168000, C340S903000
Reexamination Certificate
active
06826479
ABSTRACT:
BACKGROUND
Conventional cruise control systems regulate the speed of a vehicle at a pre-determined value. Basically, conventional cruise control systems control the speed of a vehicle by actuating the vehicle's throttle. Adaptive cruise control (“ACC”) systems provide enhancements to conventional cruise control systems. Generally, ACC systems control the speed of a vehicle (the “ACC vehicle”) based on the identification of vehicles preceding the ACC vehicle (“preceding vehicles”) that are in the path of or in the same lane as the ACC vehicle (“target vehicles”). A preceding vehicle is considered to be “in the path” of an ACC vehicle if the positional relationship between the preceding and ACC vehicles is such that if the ACC vehicle remains on its course and travels faster than the preceding vehicle, it will eventually collide with the preceding vehicle. ACC systems control the ACC vehicle's speed to follow a value set by the ACC vehicle operator when no target vehicles have been identified. However, when the target vehicle has been identified and is moving more slowly than the ACC vehicle, the ACC system will track the target vehicle and control the speed of the ACC vehicle so that the ACC vehicle will follow the target vehicle at a safe distance. When the target vehicle moves out of the path or lane of the ACC vehicle, the ACC system ceases tracking the preceding vehicle and returns the ACC vehicle to the value set by the ACC vehicle operator.
ACC systems generally include sensors, a target identification system, a control system, and a mechanism for controlling the ACC vehicle's speed. In general, the sensors obtain information regarding the speed and position (including the location and bearing)_of the ACC vehicle and the speed and relative position (including the location and azimuth angle relative to the ACC vehicle) of any preceding vehicles. This information is used by the target identification system to determine which, if any, of the preceding vehicles are target vehicles. The information is also used by the control system to control the speed of the ACC vehicle by sending the appropriate signals to the mechanism for controlling the ACC vehicle's speed.
The sensors include a sensor for sensing the relative speed, location and azimuth angle of the preceding vehicle (the “preceding vehicle sensor”) and sensors for sensing the speed, location and bearing of the ACC vehicle (the “ACC vehicle sensors”). The preceding vehicle sensor generally includes a radar source and detector. Alternatively, the preceding vehicle sensor may include any other electromagnetic (including millimeter wave and laser) and sound sources and/or detectors. The preceding vehicle sensor can obtain the location, and azimuth angle of the preceding vehicle relative to the ACC vehicle (the “relative position”) and the speed of the preceding vehicle. The ACC vehicle sensors generally include a speedometer to measure the speed of the ACC vehicle and a yaw rate sensor or a steering wheel sensor to determine the location and bearing (the “position”) of the ACC vehicle and/or the curvature of the ACC vehicle's present path from the angular velocity of the ACC vehicle.
The target identification system determines which of the preceding vehicles is a target vehicle. Additionally, the target identification system may distinguish preceding vehicles from road-side objects. The target identification system may determine which of the preceding vehicles is a target vehicle by determining which of the preceding vehicles is in the same lane as or is in the path of the ACC vehicle. Once a preceding vehicle is identified as a target vehicle, its position is monitored (“tracked”) as a target by the target vehicle sensor and its location and azimuth angle are used by the ACC control.
The control system generally includes a system that controls the ACC vehicle's speed on the basis of the position of the target vehicle relative to the ACC vehicle obtained by the preceding vehicle sensor and the speed and position of the ACC vehicle obtained from the ACC vehicle sensors. The mechanism for controlling the ACC vehicle's speed is generally a throttle control and/or a brake control which is generally controlled by the control system.
However, these known ACC systems are not typically able to accurately identify a target vehicle in certain situations. For example,
FIGS. 1A-1F
illustrate the some of the various positional situations that exist for an ACC vehicle and a preceding vehicle traveling on the same road.
FIGS. 1A-1E
illustratrate an ACC vehicle
30
following a target vehicle
40
around a curve
54
in a road
50
while
FIG. 1F
illustrates an ACC vehicle
30
following a target vehicle
40
on a road
80
. More specifically,
FIG. 1A
illustrates the positional situation where both the ACC and target vehicles
30
and
40
, respectively, have not yet entered the curve
54
and are in location
52
on road
50
.
FIG. 1B
illustrates the positional situation where the ACC vehicle
30
has not yet entered the curve
54
and is in location
52
and the target vehicle
40
is in the curve
54
.
FIG. 1C
illustrates the positional situation where both the ACC and target vehicles
30
and
40
, respectively, are in the curve
54
.
FIG. 1D
illustrates the positional situation where the ACC vehicle
30
is still in the curve
54
and the target vehicle
40
has left the curve
54
and is in location
56
.
FIG. 1E
illustrates the positional situation where both the ACC and target vehicles
30
and
40
, respectively, have left the curve and are in location
56
.
FIG. 1F
illustrates a positional situation on a road
80
where both the ACC vehicle
30
and the target vehicle
40
are on a curve in the road
80
wherein the curvature or radius of the curve is not constant. For the positional situations shown in
FIGS. 1A
,
1
C and
1
D (the “non-transient situations” or “uniform situations”), known methods can reasonably determine whether the preceding vehicle is in the same lane as the ACC vehicle. However, these known methods encounter problems when attempting to determine whether the preceding vehicle is in the path of the ACC vehicle when the preceding and ACC vehicles are in the positional situations shown in
FIGS. 1B
,
1
D and
1
F (the “transient situations” or “non-uniform situation”).
Known ACC systems have difficulty tracking target vehicles around curves in the road, namely in the “non-uniform situation.” Often in these situations, known ACC systems will completely_stop tracking the target vehicle. Generally, known ACC systems have no effective way of determining whether the preceding vehicle is in the same lane as or in the future path of the ACC vehicle for all positional situations. This problem is particularly acute in the positional situations shown in
FIGS. 1B
,
1
D and
1
F.
One known ACC system identifies which preceding vehicles are target vehicles by using the theoretical relationship between the azimuth angle and relative velocity between the ACC vehicle and the preceding vehicle as defined in a phase chart (see U.S. patent application Ser. No. 09/815187. This known ACC system works well for identifying a preceding vehicle as a target vehicle in the “non-uniform situation” because it can determine whether the preceding vehicle is in the path of the ACC vehicle. However, this known system cannot be applied to uniform situations for several reasons. One reason is that the relationship between the azimuth angle and relative velocity is determined empirically and therefore requires that a great deal of experimental data be collected and stored in the system. Another reason is that and the system requires many complex calculations.
BRIEF SUMMARY
It is an object to provide a method and apparatus that can identify whether a preceding vehicle is a target vehicle and if a target vehicle is in the same lane as an ACC vehicle in both the uniform and non-uniform situations without the disadvantages of the known systems. It is also an object to provide a method and appar
Gilson & Lione
Hofer Brinks
Louis-Jacques Jacques H.
Visteon Global Technologies Inc.
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