Automobile steering system including reaction feedback to operator

• US 5,908,457 A
• Filed: 11/21/1996
• Issued: 06/01/1999
• Est. Priority Date: 11/24/1995
• Status: Expired due to Term

• Current Assignee: Koyo Seiko Co., Ltd. (Toyota Motor Corporation)
• Original Assignee: Koyo Seiko Co., Ltd. (Toyota Motor Corporation)
• Inventors: Nakano, Shiro, Higashira, Hideki
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US08/754,525
• Time in Patent Office: 922 Days
• Field of Search: 701/41, 701/42, 701/43, 701/36, 180/169, 180/272, 180/416, 180/422, 180/446, 180/421, 180/427, 180/402, 180/441, 180/443, 180/444, 180/423, 180/429, 180/197, 180/412
• US Class Current: 701/41
• CPC Class Codes: B62D 5/006 power actuated
• 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 reaction force actuator 3 for giving reaction force to a steering wheel 2 disengaged from a steering mechanism 1 is provided. A steering control unit 4 is provided to control so that the reaction force decided in accordance with the detected results of the running speed by a vehicle speed sensor 6 and the detected results of a road surface condition by a current sensor 7a, an open air temperature sensor 7b, a wiper switch 7c and a supersonic wave sensor 7d. Also, the steering motor 5 for applying the steering force to the steering mechanism 1 is operated smaller at higher speed and larger at slower speed at running by the operation of the steering control unit 4 in accordance with the detected results of the running speed by the vehicle speed sensor 6. Therefore, the same steering feelings as those of the coupling type steering system are obtained to realize a steering system enabling the reliable steering operation to effect under the various different running conditions. Also, the bother of the steering operation at the slow speed or at the stop time is dissolved by simple construction.

Claims

1. A steering system for an automobile including a steering mechanism, comprising:

steering operating means which is mechanically disengaged from the steering mechanism;

a steering actuator applying a steering force to said steering mechanism in accordance with the operating direction and operation amount of said steering operating means;

a reaction force generator providing a reaction force to said steering operating means opposite to the operating direction of said steering operating means;

a steering controller controlling the steering force generated by said steering actuator in accordance with the magnitude of the steering force applied to said steering operating means against the reaction force provided by said reaction force generator;

a vehicle speed detector detecting the running speed of the automobile;

a road surface condition detector detecting the traction of the road surface on which the automobile is running; and

a reaction force controller controlling the reaction force generated by said reaction force generator in accordance with the traction detected by said road surface condition detector and the vehicle speed detected by said vehicle speed detector.

2. A steering system for an automobile as set forth in claim 1, wherein said road surface condition detector includes at last one of a sensor for detecting the road surface reaction force applied to the wheels for steering use, a temperature sensor for detecting the open air temperature, a sensor for detecting the operating state of a window wiper, and a sensor for detecting the unevenness of the road surface.

3. A steering system for an automobile as set forth in claim 2, wherein said steering actuator includes a motor and said sensor for detecting the road surface reaction force applied to the wheels for steering use includes a current sensor for detecting the motor current of said motor.

4. A steering system for an automobile including a steering mechanism, comprising:

steering operating means which is mechanically disengaged from the steering mechanism;

a steering actuator applying a steering force to said steering mechanism in accordance with the operating direction and operation amount of said steering operating means;

a reaction force generator providing a reaction force to said steering operating means opposite to the operating direction of said steering operating means;

a steering controller controlling the steering force generated by said steering actuator in accordance with the magnitude of the steering force applied to said steering operating means against the reaction force provided by said reaction force generator; and

a vehicle speed detector detecting the running speed of the automobile;

said steering controller being constructed to control the variation ratio of the operation amount of said steering actuator with respect to the operating amount of said steering operating means based on the detected result of said vehicle speed detector.

5. A steering system for an automobile as set forth in claim 4, wherein said road surface condition detector includes at least one of a sensor for detecting the road surface reaction force applied to the wheels for steering use, a temperature sensor for detecting the open air temperature, a sensor for detecting the operating state of a window wiper, and a sensor for detecting the unevenness of the road surface.

6. A steering system for an automobile as set forth in claim 5, wherein said steering actuator includes a motor and said sensor for detecting the road surface reaction force applied to the wheels for steering use includes a current sensor for detecting the motor current of said motor.

7. A steering system for an automobile including a steering mechanism, comprising:

steering operating means which is mechanically disengaged from the steering mechanism;

a steering actuator applying a steering force to said steering mechanism in accordance with the operating direction and operation amount of said steering operating means;

a reaction force generator providing a reaction force to said steering operating means opposite to the operating direction of said steering operation means;

a steering controller controlling the steering force generated by said steering actuator with the magnitude of the steering force applied to said steering operating means against the reaction force provided by said reaction force generator;

a vehicle speed detector detecting the running speed of the automobile;

a road surface condition detector detecting the traction of the road surface on which the automobile is running; and

a reaction force controller controlling the reaction force generated by said reaction force generator in accordance with the traction detected by said road surface condition detector and the vehicle speed detected by said vehicle speed detector;

said steering controller being constructed to control the variation ratio of the operation amount of said steering actuator with respect to the operation amount of said steering operating means based on the detected result of said vehicle speed detector.

8. A steering system for an automobile as set forth in claim 7, wherein said road surface condition detector includes at least one of a sensor for detecting the road surface reaction force applied to the wheels for steering use, a temperature sensor for detecting the open air temperature, a sensor for detecting the operating state of a window wiper, and a sensor for detecting the unevenness of the road surface.

9. A steering system for an automobile as set forth in claim 8, wherein said steering actuator includes a motor and said sensor for detecting the road surface reaction force applied to the wheels for steering use includes a current sensor for detecting the motor current of said motor.