Steering control apparatus

• US 6,032,757 A
• Filed: 01/12/1998
• Issued: 03/07/2000
• Est. Priority Date: 01/22/1997
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kawaguchi, Hiroshi, Sugitani, Nobuyoshi, Okada, Akio
• Primary Examiner(s): Graham, Matthew C.
• Assistant Examiner(s): RODRIGUEZ, PAMELA
• Application Number:
  US09/005,028
• Time in Patent Office: 785 Days
• Field of Search: 180/446, 180/443, 180/402, 180/412, 180/421, 180/422, 180/423, 180/427, 180/416, 180/197
• US Class Current: 180/446
• CPC Class Codes: B62D 6/002 computing target steering angles for front or rear wheels B62D7/159 takes precedence
• CPC Class Codes: B62D 6/008 Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications

Abstract

A steering control apparatus of the present invention comprises: a steering shaft on which a steering effort is exerted through a steering wheel; a steering angle detecting device for detecting an angle of rotation of the steering shaft; a turning device for turning a steered wheel, the turning device being mechanically separated from the steering shaft; a target control amount calculating device for calculating a target control amount as a target of turning control, based on a detection result of the steering angle detecting device; a turning control device for outputting a turning control signal according to the target control amount to the turning device and controlling drive of the turning device so that a turning amount of the steered wheel becomes the target control amount; and a correction device for correcting the turning control signal outputted, based on a running status of a vehicle.

Claims

1. A steering control apparatus, comprising:

a steering shaft to which a steering wheel is mounted and on which the steering wheel exerts a steering effort;

steering angle detecting means for detecting an angle of rotation of said steering shaft;

turning means for turning a steered wheel, said turning means being mechanically separated from said steering shaft;

target control amount calculating means for calculating a target control amount as a target of turning control, based on a detection result of said steering angle detection means;

turning control means for outputting a turning control signal according to said target control amount to said turning means and controlling drive of said turning means so that a turning amount of said steered wheel becomes said target control amount; and

correction means for correcting said turning control signal outputted, based on a running status of a vehicle;

wherein said turning control means calculates a control displacement amount Ms defined by the following equation;

space="preserve" listing-type="equation">Ms=Gs×

(θ

-bX)

where θ

is said target control amount, bX is said turning amount, and Gs is a turning gain coefficient, and said turning control means outputs information including this control displacement amount Ms as the turning control signal, and said turning means turns the steered wheel according to said control displacement amount Ms obtained from said turning control means.

2. A steering control apparatus according to claim 1, wherein the correction of said turning control signal by said correction means is effected by changing said turning gain coefficient Gs, based on the running status of the vehicle.

3. A steering control apparatus according to claim 2, wherein said running status is a status concerning a vehicle speed.

4. A steering control apparatus according to claim 2, wherein said running status is a status concerning the angle of rotation of said steering shaft.

5. A steering control apparatus according to claim 2, wherein said running status is a status concerning a road friction coefficient.

6. A steering control apparatus according to claim 2, wherein said running status is a combination of two or more of those concerning a vehicle speed, the angle of rotation of said steering shaft, and a road friction coefficient.

7. A steering control apparatus according to claim 2, further comprising steering shaft driving means for rotating said steering shaft, steering shaft control means for controlling the steering shaft driving means, steering effort detecting means for detecting the steering effort exerted on said steering shaft through said steering wheel, and turning reaction force detecting means for detecting a turning reaction force exerted on said steered wheel,

wherein said steering shaft control means calculates a steering rotation control amount Mm defined by the following equation:

space="preserve" listing-type="equation">Mm=Gm×

(aT-F)

where aT is a force proportional to said steering effort, F is a force according to said turning reaction force, and Gm is a steering gain coefficient; and

wherein said steering shaft driving means rotates said steering shaft according to said steering rotation control amount Mm obtained from said steering shaft control means.