Steering control system for vehicle

• US 6,338,015 B1
• Filed: 09/11/1998
• Issued: 01/08/2002
• Est. Priority Date: 09/13/1997
• Status: Expired due to Term

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Kawagoe, Hiroyuki, Matsuno, Kaoru, Ishida, Shinnosuke, Teramoto, Tomoaki
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): To, Tuan C
• Application Number:
  US09/151,760
• Time in Patent Office: 1,215 Days
• Field of Search: 701/41, 701/28, 701/42, 364/424.02, 180/446, 180/168, 180/167, 180/233, 180/140, 180/443, 180/79.1, 318/580
• US Class Current: 701/41
• 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 1/286 Systems for interrupting non-mechanical steering due to driver intervention
• 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

A system for controlling steering of a vehicle, including a steering means such as a steering wheel with an electric motor which assists steering of the driven wheels of the vehicle, first steering control means for controlling the motor, a CCD camera for detecting a lane condition of a road on which the vehicle travels, a yaw rate sensor for detecting motion of the vehicle, steering assist torque calculating means for calculating a steering assist torque necessary for holding the lane, a torque sensor for detecting an actual steering torque manually applied to the steering means by the driver, and second steering control means for calculating a torque command to be output to the first steering control means based on the steering assist torque calculated by the steering assist torque calculating means and the actual steering torque such that the torque command decreases. In the system, the second steering control means transfers to the first steering control means an index indicative of a condition under which the steering assist torque was calculated, or an index indicative of an order in which the values of the steering assist torque are tansferred, thereby ensuring appropriate and highly reliable communication between the two control means.

Claims

1. A system for controlling steering of a vehicle, comprising:

steering means having an actuator which steers driven wheels of the vehicle;

first steering control means for controlling the actuator;

first detecting means comprising a camera that images a road ahead of the vehicle for detecting a lane boundary condition of the road on which the vehicle travels;

second detecting means for detecting motion of the vehicle;

steering assist torque calculating means for calculating a steering assist torque necessary for holding a positional relationship between the vehicle and the lane condition;

torque detecting means for detecting a steering torque manually applied to the steering means by the driver; and

second steering control means for calculating a torque command to be output to the first steering control means based on the steering assist torque calculated by the steering assist torque calculating means and the detected steering torque detected by the torque detecting means to control the actuator such that the torque command decreases;

wherein;

the second steering control means transfers to the first steering control means an index indicative of a condition under which the steering assist torque was calculated, when the second steering control means transfers the steering assist torque to the first steering control means.

2. A system according to claim 1, wherein the second steering control means transfers to the first steering control means an index indicative of an order in which the steering assist torque are transferred, when the second steering control means transfers the steering assist torque to the first steering control means.

3. A system according to claim 1, wherein the second steering control means transfers to the first steering control means an index indicative of a condition of a communication system.

4. A system according to claim 1, wherein the second steering control means transfers to the first steering control means an index indicating which of control by the first steering control means and control by the second steering control means is in effect.

5. A system according to claim 1, wherein the first steering control means transfers to the second steering control means the detected steering torque in response to the transferred steering assist torque.

6. A system according to claim 2, wherein the first steering control means transfers to the second steering control means the detected steering torque in response to the transferred steering assist torque.

7. A system according to claim 1, wherein the first steering control means transfers to the second steering control means an index indicative of an order in which the detected torques are transferred in response to the transferred steering assist torque.

8. A system according to claim 2, wherein the first steering control means transfers to the second steering control means an index indicative of an order in which the detected torques are transferred in response to the transferred steering assist torque.

9. A system according to claim 1, wherein the first steering control means transfers to the second steering control means an index indicative of a fail condition of the first steering control system.

10. A system according to claim 1, wherein the first steering control means transfers to the second steering control means an index indicative of a condition of the communication system.

11. A system according to claim 1, wherein the first steering control means transfers to the second steering control means an index indicating which of control by the first steering control means and control by the second steering control means is in effect.

12. A method of controlling steering of a vehicle, having:

steering means having an actuator which steers driven wheels of the vehicle;

first steering control means for controlling the actuator;

first detecting means comprising a camera that images a road ahead of the vehicle for detecting a lane boundary condition of the road on which the vehicle travels;

second detecting means for detecting motion of the vehicle;

steering assist torque calculating means for calculating a steering assist torque necessary for holding a positional relationship between the vehicle and the lane condition;

torque detecting means for detecting a steering torque manually applied to the steering means by the driver; and

second steering control means for calculating a torque command to be output to the first steering control means based on the steering assist torque calculated by the steering assist torque calculating means and the detected steering torque detected by the torque detecting means to control the actuator such that the torque command decreases;

wherein said method comprises the step of;

transferring to the first steering control means an index indicative of a condition under which the steering assist torque was calculated, when the second steering control means transfers the steering assist torque to the first steering control means.

13. A method according to claim 12, wherein transferring to the first steering control means an index indicative of an order in which the steering assist torque are transferred, when the second steering control means transfers the steering assist torque to the first steering control means.

14. A method according to claim 12, wherein transferring to the first steering control means an index indicative of a condition of a communication system.

15. A method according to claim 12, wherein transferring to the first steering control means an index indicating which of control by the first steering control means and control by the second steering control means is in effect.

16. A method according to claim 12, wherein transferring to the second steering control means the detected steering torque in response to the transferred steering assist torque.

17. A method according to claim 13, wherein transferring to the second steering control means the detected steering torque in response to the transferred steering assist torque.

18. A method according to claim 13, wherein transferring to the second steering control means an index indicative of an order in which the detected torques are transferred in response to the transferred steering assist torque.

19. A method according to claim 13, wherein transferring to the second steering control means an index indicative of an order in which the detected torques are transferred in response to the transferred steering assist torque.

20. A method according to claim 12, wherein transferring to the second steering control means an index indicative of a fail condition of the first steering control system.

21. A method according to claim 12, wherein transferring to the second steering control means an index indicative of a condition of the communication system.

22. A method according to claim 12, wherein transferring to the second steering control means an index indicating which of control by the first steering control means and control by the second steering control means is in effect.

23. A computer program embodied on a computer-readable medium for controlling steering of a vehicle having:

steering means having an actuator which steers driven wheels of the vehicle;

first steering control means for controlling the actuator;

first detecting means comprising a camera that images a road ahead of the vehicle for detecting a lane boundary condition of the road on which the vehicle travels;

second detecting means for detecting motion of the vehicle;

steering assist torque calculating means for calculating a steering assist torque necessary for holding a positional relationship between the vehicle and the lane condition;

torque detecting means for detecting a steering torque manually applied to the steering means by the driver; and

second steering control means for calculating a torque command to be output to the first steering control means based on the steering assist torque calculated by the steering assist torque calculating means and the detected steering torque detected by the torque detecting means to control the actuator such that the torque command decreases;

wherein said computer program comprising the step of;

transferring to the first steering control means an index indicative of a condition under which the steering assist torque was calculated, when the second steering control means transfers the steering assist torque to the first steering control means.