Vehicle Steering Device

• US 20170151978A1
• Filed: 11/23/2016
• Published: 06/01/2017
• Est. Priority Date: 11/30/2015
• Status: Active Grant

• Current Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Original Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Inventors: OYA, Toshiaki, OKADA, Kotaro
• Granted Patent: US 10,011,297 B2
• Time in Patent Office: Days
• CPC Class Codes: B62D 15/022 on or near the connection between the steering wheel and steering column
• CPC Class Codes: B62D 15/0235 by measuring or deriving directly at the electric power steering motor
• CPC Class Codes: B62D 5/001 Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup
• CPC Class Codes: B62D 5/005 means for generating torque on steering wheel or input member, e.g. feedback
• CPC Class Codes: B62D 5/0415 the axes being coaxial
• CPC Class Codes: B62D 5/0418 Electric motor acting on road wheel carriers
• CPC Class Codes: B62D 5/046 Controlling the motor
• CPC Class Codes: B62D 5/0481 monitoring the steering system, e.g. failures
• CPC Class Codes: B62D 5/0484 for reaction to failures, e.g. limp home
• CPC Class Codes: B62D 5/0487 detecting motor faults B62D5/0496 takes precedence
• CPC Class Codes: B62D 6/002 computing target steering angles for front or rear wheels B62D7/159 takes precedence

Abstract

A vehicle steering device includes: a target-steered-angle setting unit configured to set a left target steered angle that is a target value of the steered angle of a left steered wheel and a right target steered angle that is a target value of the steered angle of a right steered wheel; left motor controllers configured to control a left steering motor based on a left-steered-angle deviation that is a difference between the left steered angle and the left target steered angle; right motor controllers configured to control a right steering motor based on a right-steered-angle deviation that is a difference between the right steered angle and the right target steered angle; and an abnormality determination unit configured to determine that an abnormality has occurred when an absolute value of difference between the left-steered-angle deviation and the right-steered-angle deviation is equal to or larger than a first threshold.

Claims

1. A vehicle steering device comprising:

a steering member that is operated for steering;

a left steering operation mechanism configured to turn a left steered wheel;

a right steering operation mechanism configured to turn a right steered wheel, the steering member and the left steering operation mechanism being not mechanically coupled together, the steering member and the right steering operation mechanism being not mechanically coupled together, the left steering operation mechanism being driven by a left steering motor, and the right steering operation mechanism being driven by a right steering motor;

a target steered angle setter configured to set a left target steered angle that is a target value of a steered angle of the left steered wheel and a right target steered angle that is a target value of a steered angle of the right steered wheel;

a left-steered-angle acquisition device configured to acquire a left steered angle that is the steered angle of the left steered wheel;

a right-steered-angle acquisition device configured to acquire a right steered angle that is the steered angle of the right steered wheel;

a left motor controller configured to control the left steering motor so that a left-steered-angle deviation that is a difference between the left steered angle and the left target steered angle decreases;

a right motor controller configured to control the right steering motor so that a right-steered-angle deviation that is a difference between the right steered angle and the right target steered angle decreases; and

a determiner configured to determine that an abnormality has occurred when an absolute value of difference between the left-steered-angle deviation and the right-steered-angle deviation is equal to or larger than a first threshold.

2. The vehicle steering device according to claim 1, further comprising:

a determiner configured to determine that an abnormality has occurred when at least one of an absolute value of a time rate of change of the left-steered-angle deviation and an absolute value of a time rate of change of the right-steered-angle deviation is smaller than a second threshold.

3. The vehicle steering device according to claim 1, further comprising:

a determiner configured to determine that an abnormality has occurred when an absolute value of the left-steered-angle deviation is larger than a third threshold and an absolute value of a time rate of change of the left-steered-angle deviation is smaller than a fourth threshold, or when an absolute value of the right-steered-angle deviation is larger than the third threshold and an absolute value of a time rate of change of the right-steered-angle deviation is smaller than the fourth threshold.

4. The vehicle steering device according to claim 1, further comprising:

a vehicle-speed acquisition device configured to acquire a vehicle speed; and

a first threshold changer configured to change the first threshold in accordance with the vehicle speed acquired by the vehicle-speed acquisition device.

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

a vehicle-speed acquisition device configured to acquire a vehicle speed;

a first threshold changer configured to change the first threshold in accordance with the vehicle speed acquired by the vehicle-speed acquisition device; and

a second threshold changer configured to change the second threshold in accordance with the vehicle speed acquired by the vehicle-speed acquisition device.

6. The vehicle steering device according to claim 3, further comprising:

a vehicle-speed acquisition device configured to acquire a vehicle speed;

a first threshold changer configured to change the first threshold in accordance with the vehicle speed acquired by the vehicle-speed acquisition device;

a third threshold changer configured to change the third threshold in accordance with the vehicle speed acquired by the vehicle-speed acquisition device; and

a fourth threshold changer configured to change the fourth threshold in accordance with the vehicle speed acquired by the vehicle-speed acquisition device.