Steering control device

• US 20040104066A1
• Filed: 10/10/2003
• Published: 06/03/2004
• Est. Priority Date: 10/11/2002
• Status: Active Grant

• Current Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Original Assignee: Toyoda Koki Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Sakai, Atsuo
• Granted Patent: US 7,325,644 B2
• Time in Patent Office: Days
• US Class Current: 180/402
• CPC Class Codes: B62D 5/0469 End-of-stroke control
• 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 device (200) is provided with a end-of-movement reaction force generation unit (an end reaction force control portion (20)). An end reaction force generating current i₂ which act as return a handle toward a straight-ahead position is rapidly generated in the vicinity of an upper and a lower limit of a vehicle wheel steering range. For example, a reaction force motor (4) may be additionally commanded using a newly generated command current i₂. Accordingly, an output torque of the reaction force motor (4) becomes proportional to a new command value in of an Equation i_n =i₁ +12, where i₁ is a current command of a reaction force control portion (5). As a result of configuring the end-of-movement reaction force generation unit is this manner, for example, it is possible to generate a virtual contact resistance force (a steering reaction force) for a steering angle 6 without causing heat build-up, or the like, of a motor, when no physical limit (an end-of-movement of contact point) is provided for a rotation range of a steering wheel (handle).

Claims

1. A steering control device including a steering wheel steering mechanism having a steering actuator that imparts a steering reaction force to a steering wheel, and a vehicle wheel steering mechanism having a vehicle wheel steering actuator that drives a vehicle wheel steering shaft, comprising:

a steering angle sensor that detects a steering angle θ

of the steering wheel; and

a steering change amount sensor that detects a steering change amount X_a in the vehicle wheel steering mechanism;

wherein

the steering wheel steering mechanism includes an end-of-movement reaction force generation unit that respectively generates, in a vicinity of an upper limit point θ

_E of the steering angle θ and

a vicinity of a lower limit point −

θ

_E of the steering angle θ

, a virtual contact resistance force that inhibits the steering angle θ

from exceeding threshold values of a predetermined permissible range (−

θ

_E <

θ

<

θ

_E) of the steering angle θ

, based on the steering angle θ

, the steering change amount X_a or a command value X_n for the steering change amount X_a.

2. The steering control device according to claim 1, wherein the steering control device is configured such that the steering wheel steering mechanism and the vehicle wheel steering mechanism are mechanically separate, and are operationally connected by an electronic mechanism rather than by a mechanical connection.

3. The steering control device according to f claim 2, further comprising:

a steering angle threshold value variation unit that dynamically changes the upper limit point θ

E and the lower limit point −

θ

_E of the permissible range (−

θ

_E <

θ

<

θ

_E), based on a vehicle speed v.

4. The steering control device according claim 3, further comprising:

a steering change amount threshold value variation unit that dynamically changes respective upper and lower limits of a permissible range (−

X_E <

X_n <

X_E) of the command value X_n, based on the vehicle speed v.

5. The steering control device according to claim 2, further comprising:

a steering change amount threshold value variation unit that dynamically changes respective upper and lower limits of a permissible range (−

X_E <

X_n <

X_E) of the command value X_n, based on the vehicle speed v.

6. The steering control device according claim 1, further comprising:

a steering angle threshold value variation unit that dynamically changes the upper limit point θ

_E and the lower limit point −

θ

_E of the permissible range (−

θ

_E <

θ

<

θ

_E), based on a vehicle speed v.

7. The steering control device according to claim 6, further comprising:

a steering change amount threshold value variation unit that dynamically changes respective upper and lower limits of a permissible range (−

X_E <

X_n <

X_E) of the command value X_n, based on the vehicle speed v.

8. The steering control device according claim 1, further comprising:

a steering change amount threshold value variation unit that dynamically changes respective upper and lower limits of a permissible range (−

X_E <

X_n <

X_E) of the command value X_n, based on the vehicle speed v.

9. The steering control device according to claim 1, further comprising:

a vehicle wheel steering limiter for inhibiting or preventing a command value for the vehicle wheel steering actuator from exceeding threshold values, this vehicle wheel steering limiter being configured from a steering angle limiter for inhibiting the steering angle θ

from exceeding threshold values.

10. The steering control device according to claim 1, wherein the vehicle wheel steering limiter for inhibiting or preventing a command value for the vehicle wheel steering actuator from exceeding the threshold values is configured from a position command limiter for inhibiting the command value X_n from exceeding threshold values.