Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Vehicle subsystem or accessory control
Reexamination Certificate
1998-10-09
2001-01-09
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Vehicle subsystem or accessory control
C701S028000, C701S042000, C180S421000, C180S446000
Reexamination Certificate
active
06173222
ABSTRACT:
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to an autonomous intelligent vehicle. More particularly, the present invention relates to a steering control system and method for an autonomous intelligent vehicle in which information of near and distant road conditions is received through cameras and used to control the steering of a vehicle.
(b) Description of the Related Art
There has been continued, rapid development in automotive technology since the inception of the automobile industry. In recent times, advances have been concentrated more in the area of electronics than in mechanics. For example, there have been many electronics-related developments that improve engine performance and efficiency, in addition to more recent advances that provide intelligent safety capabilities (e.g., air bags that are activated for operation only if the passenger is over a predetermined weight) and technology that will enable the application of vehicles that can drive without the aid of a driver.
With regard to such autonomous intelligent vehicles, various institutions and organizations are vigorously pursuing research to perfect this technology. An example is the NAVLAB vehicle developed in the United States which is capable of driving by itself on a road that is clear of obstacles. The GRAFE vehicle developed in Germany has capabilities that its developers claim enable the vehicle to travel driver-free on the Autobahn. These and other conventional autonomous intelligent vehicles utilize a camera that supplies road images which are processed and analyzed. From the analysis, automatic controls are performed to maintain the vehicle in a certain lane or side of the road by steering the vehicle, and to maintain the vehicle at a suitable speed.
However, since only a single camera is used in these conventional vehicles to detect road conditions, either smooth cornering or precise lane maintenance is compromised. That is, if the single camera is positioned at an optimal location on the vehicle to maintain the vehicle precisely in the car lane, approaching curves in the road can not be detected such that steering control through the curve is not smooth. On the other hand, if the camera is positioned to detect approaching turns in the road, minute adjustments to maintain the vehicle precisely in the center of the car lane can not be made.
SUMMARY OF THE INVENTION
The present invention has been made in an effort to solve the above problems.
It is an object of the present invention to provide a steering control system and method for autonomous intelligent vehicles in which two or more cameras are utilized and detected image signals are processed in parallel such that control for both approaching curves and to maintain the vehicle precisely between the road lane markers can be performed.
To achieve the above object, the present invention provides a steering control system and method for autonomous intelligent vehicles. The system includes image input means for supplying images of in front of the vehicle, and a plurality of elements of which are mounted at predetermined locations on the vehicle; a plurality of image grabbers which receive images from the image input means and capture image signals corresponding to the road; a first controller determining if the vehicle is being driven within the lane using near image signals received from the image grabbers; a second controller determining a driving direction of the vehicle and detecting curves in the road using distant image signals received from the image grabbers; a steering controller analyzing the information received from the first and second controllers to determine a steering angle and direction, and which outputs control signals corresponding to the analysis; and drive means for driving a steering system of the vehicle in a direction and angle corresponding to the control signals received from the steering controller.
According to a feature of the present invention, the image input means comprises first and second cameras mounted on opposite sides of the front of a vehicle; and a third camera mounted to an upper, center portion of the windshield of a vehicle.
According to another feature of the present invention, the plurality of image grabbers comprises a first, second and third image grabber corresponding respectively to the first, second and third cameras, the image grabbers processing image data received from the cameras.
The method of the present invention includes the steps of supplying near and distant images of in front of a vehicle after the images are processed to a predetermined state; capturing image signals corresponding to the road from the near and distant images, and determining a driving direction of the vehicle and detecting curves in the road from the distant images, and determining if the vehicle is being driven off-center from road lane markers using the near images; determining a steering angle and direction by analyzing the information on the driving direction, curves in the road and whether the vehicle is being driven off-center from the road lane markers; and driving a steering system of the vehicle according to the determined steering angle and direction to control steering of the vehicle.
According to a feature of the present invention, curves in the road are detected from the distant images using Equation 1 below:
&agr;
n&thgr;n
+&agr;(
n+
1)&thgr;(
n+
1)+
a
(
n+
2)&thgr;(
n+
2)+. . .=&thgr;total Equation 1
According to another feature of the present invention, the steering angle is determined using Equation 2 below:
Steering Control=&bgr;×off-center rate+&ggr;×driving direction+&dgr;×vehicle speed, Equation 2
where &bgr;, &ggr; and &dgr; are measured ratio constants, and &bgr;>&ggr;>&dgr;.
REFERENCES:
patent: 5559695 (1996-09-01), Daily
patent: 5568406 (1996-10-01), Gerber
patent: 5762157 (1998-06-01), Uehara
patent: 5908457 (1999-06-01), Higashira et al.
Kim Gi-seok
Seo Jae-hyung
Arthur Gertrude
Christie Parker & Hale LLP
Cuchlinski Jr. William A.
Hyundai Motor Company
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