Lane moving-out prevention system for vehicle and the method thereof

• US 6,009,377 A
• Filed: 12/19/1997
• Issued: 12/28/1999
• Est. Priority Date: 01/09/1997
• Status: Expired due to Fees

• Current Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Original Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Inventors: Hiwatashi, Yutaka
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US08/995,065
• Time in Patent Office: 739 Days
• Field of Search: 701/9, 701/23, 701/41, 701/53, 701/301, 340/937, 340/425.5, 340/436, 340/438, 180/204, 180/6.2, 180/6.24, 382/199
• US Class Current: 701/301
• CPC Class Codes: B60T 2201/08 Lane monitoring; Lane Keeping Systems
• CPC Class Codes: B60T 2201/087 using active steering actuation
• CPC Class Codes: B62D 15/025 Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation B62D1/28 takes precedence

Abstract

When a vehicle is moving out of a lane of a road, an image processing computer unit judges the hazardous condition. Then, a power steering control computer unit calculates a correction reaction force based on the steering angular velocity and increases a steering reaction force so as to generate a large steering effort. This lane moving-out prevention system is constituted such that only when the steering angular velocity is large, i.e., when a driver turns a steering wheel sharply, the steering reaction force is increased, thereby no additional reaction force is produced when the driver makes a normal turn.

Claims

1. A lane moving-out prevention system of a vehicle having a power steering mechanism including a steering wheel and a power assist apparatus for preventing said vehicle from moving out of a lane of a road, comprising:

stereoscopic cameras for taking an image of objects outside said vehicle and for outputting an image signal of said objects;

monitoring means responsive to said image signal for recognizing a lane traced by said vehicle;

reference position establishing means for establishing a reference position of said lane;

steering speed detecting means for detecting a steering speed;

distance detecting means for detecting a distance from said vehicle to said reference position;

departing speed detecting means for detecting a speed of said vehicle departing from said reference position;

returning speed detecting means for detecting a speed of said vehicle returning to said reference position; and

control means for controlling a steering reaction force of said power steering mechanism based on said steering speed of said steering wheel when said vehicle is away from said reference position by more than a specified value.

2. The lane moving-out prevention system according to claim 1, wherein

said steering reaction force is increased according to said steering speed when said steering wheel is turned in the direction of departing from said reference position.

3. The lane moving-out prevention system according to claim 1, wherein

said steering reaction force is reduced according to said steering speed when said steering wheel is turned in the direction of returning to said reference position.

4. The lane moving-out prevention system according to claim 1, wherein

said steering reaction force is increased according to said steering speed and said departing speed when said steering wheel is turned in the direction of departing from said reference position.

5. The lane moving-out prevention system according to claim 1, wherein

said steering reaction force is reduced according to said steering speed and said returning speed when said steering wheel is turned in the direction of returning to said reference position.

6. The lane moving-out prevention system according to claim 1, wherein

said steering reaction force is increased according to said steering speed and said distance when said steering wheel is turned in the direction of departing from said reference position.

7. The lane moving-out prevention system according to claim 1, wherein

said steering reaction force is reduced according to said steering speed and said distance when said steering wheel is turned in the direction of returning to said reference position.

8. The lane moving-out prevention system according to claim 1, wherein

said steering reaction force is increased according to said steering speed, said distance and said departing speed when said steering wheel is turned in the direction of departing from said reference position.

9. The lane moving-out prevention system according to claim 1, wherein

said steering reaction force is reduced according to said steering speed, said distance and said returning speed when said steering wheel is turned in the direction of returning to said reference position.

10. A lane moving-out prevention method of a vehicle having a power steering mechanism including a steering wheel and a power assist apparatus for preventing said vehicle from moving out of a lane of a road, comprising the steps of:

generating an image signal of objects outside of said vehicle by stereoscopic cameras;

recognizing a lane traced by said vehicle responsive to said image signal;

establishing a reference position of said lane;

determining steering speed of the steering wheel;

detecting a distance of said vehicle from said reference position;

detecting a departing speed from said reference position;

detecting a returning speed to said reference position; and

controlling a steering reaction force of said power steering mechanism based on said steering speed of said steering wheel when said vehicle is away from said reference position by more than a specified distance.

11. A lane moving-out prevention system of a vehicle having a power steering mechanism with a steering wheel and a power assist apparatus mounted on said vehicle and mechanically and hydraulically connected between said steering wheel and a vehicle wheel for assisting a driver to steer via a steering column, a steering angle sensor mounted on said steering column for detecting steering angle and for generating a steering angle signal, and a vehicle speed sensor mounted on said vehicle for detecting vehicle speed and for producing a vehicle speed signal, the system further comprising:

stereoscopic cameras for taking an image of objects outside said vehicle and for outputting an image signal of said objects;

monitoring means responsive to said image signal for recognizing a positional relationship between a lane to be traced and said vehicle and for producing a distance signal;

first computing means responsive to said distance signal, vehicle speed and said steering angle signal for establishing a reference position of said lane and a road condition and for generating a recognition signal; and

second computing means responsive to said recognition signal, said steering angle signal and said vehicle speed signal for controlling a steering reaction force of said power steering mechanism as a function of steering speed thereof when a present position of said vehicle deviates from said reference position by more than a predetermined position so as to improve responsiveness of steering operations in accordance with said steering speed even when said steering wheel is suddenly turned and to effectively avoid dangerous situations even when said vehicle moves unintentionally out of said lane.

12. The system of claim 11, wherein

the steering speed is determined by differentiating the steering angle represented by the steering angle signal from the steering angle sensor.

13. The system of claim 12, wherein the differentiating is provided by digital filtering.

14. The system of claim 12, wherein the differentiating is provided by a CR circuit through which the steering angle signal is passed.

15. The system of claim 12, wherein the steering reaction force is obtained from a correction reaction force provided by a map of gain vs. steering speed.

16. The system of claim 15, wherein the gain is a constant when said steering speed is greater than a predetermined value.

17. The system of claim 15, wherein the gain is a linear function of said steering speed when said steering speed is less than said predetermined value.

18. The system of claim 15, wherein the gain has a dead zone at a low range of said steering speed representing a normal turn of the vehicle.

19. The system of claim 15, wherein the steering reaction force is further obtained by a correction reaction force provided by a map of another gain vs. a speed represented by differentiating distance between the vehicle and the reference position.

20. The system of claim 15, wherein the steering reaction force is further obtained by a correction reaction force provided by a map of another gain vs. distance of the vehicle with respect to the reference position.