Motor-driven steering controller and automobile anti-skid controller

• US 20030221898A1
• Filed: 04/08/2003
• Published: 12/04/2003
• Est. Priority Date: 04/08/2002
• Status: Active Grant

• Current Assignee: Advics Company Limited (Aisin Corp.), Aisin Seiki Co., Ltd. (Aisin Corp.), Jtekt Corporation (Toyota Motor Corporation)
• Original Assignee: Aisin Seiki Kabushiki Kaisha Toyoda KOKI Kabushiki Kaisha and Advics Company Limited
• Inventors: Tanaka, Wataru, Kato, Hiroaki, Ono, Eiichi, Asano, Katsuhiro, Asano, Kenji, Yasui, Yoshiyuki, Muragishi, Yuji, Momiyama, Minekazu
• Granted Patent: US 7,374,014 B2
• Time in Patent Office: Days
• US Class Current: 180/446
• CPC Class Codes: B60T 2220/03 Driver counter-steering; Avoidance of conflicts with ESP control
• CPC Class Codes: B60T 2260/024 Yawing moment compensation during mu-split braking
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60T 8/1764 Regulation during travel on surface with different coefficients of friction, e.g. between left and right sides, mu-split or between front and rear
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2520/10 Longitudinal speed
• CPC Class Codes: B60W 2520/30 Wheel torque
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 2720/14 Yaw
• CPC Class Codes: B62D 5/046 Controlling the motor
• CPC Class Codes: B62D 5/0472 for damping vibrations
• CPC Class Codes: B62D 6/003 in order to control vehicle yaw movement, i.e. around a vertical axis B62D6/007 takes precedence

Abstract

A motor-driven steering controller for controlling a steering wheel of a vehicle. The controller includes a steering torque controlling unit, a braking force estimating unit, a right and left braking force difference estimating unit and an assist steering torque providing unit. The steering torque controlling unit controls a steering torque on the steering wheel depending on a steering operation. The braking force estimating unit estimates braking forces to be imposed on wheels of the vehicle. The right and left braking force difference estimating unit estimates difference between the braking forces to be imposed on the right and left wheels each estimated by the braking forces estimating unit. The assist steering torque providing unit provides an assist steering torque for the steering torque controlling unit on the basis of the difference in braking force between right and left wheels estimated by the right and left braking force difference estimating unit.

Claims

1. A motor-driven steering controller for controlling a steering wheel of a vehicle, comprising:

a steering torque controlling unit for controlling a steering torque on the steering wheel depending on a steering operation of the vehicle;

a braking force estimating unit for estimating braking forces to be imposed on wheels of the vehicle;

a right and left braking force difference estimating unit for estimating difference between the braking forces to be imposed on the right and left wheels each estimated by the braking forces estimating unit; and

an assist steering torque providing unit for providing an assist steering torque for the steering torque controlling unit on the basis of the difference in braking force between right and left wheels estimated by the right and left braking force difference estimating unit.

2. The motor-driven steering controller as claimed in claim 1, further comprising:

a vehicle stability controlling unit for controlling a stability of the vehicle depending on a traveling state of the vehicle;

wherein the assist steering torque providing unit is arranged so as to inhibit provision of the assist steering torque when the stability of the vehicle is controlled by the vehicle stability controlling unit.

3. The motor-driven steering controller as claimed in claim 1, wherein the assist steering torque providing unit is arranged so as to set the assist steering torque depending on a temporal variation in the difference between the braking forces of the right and left wheels estimated by the right and left braking force difference estimating unit.

4. The motor-driven steering controller as claimed in claim 1, wherein the assist steering torque providing unit is arranged so as to set the assist steering torque larger as a velocity of the vehicle increases.

5. The motor-driven steering controller as claimed in claim 1, wherein the assist steering torque providing unit is arranged so as to set the assist steering torque larger when the vehicle takes a turn than when the vehicle goes straight ahead.

6. An anti-skid controller in a vehicle including a motor-driven steering controller for controlling a steering wheel of the vehicle, wherein the motor-driven steering controller includes a steering torque controlling unit for controlling a steering torque on the steering wheel depending on a steering operation of the vehicle, a braking force estimating unit for estimating braking forces to be imposed on wheels of the vehicle, a right and left braking force difference estimating unit for estimating difference between the braking forces to be imposed on the right and left wheels each estimated by the braking forces estimating unit, and an assist steering torque providing unit for providing an assist steering torque for the steering torque controlling unit on the basis of the difference in braking force between right and left wheels estimated by the right and left braking force difference estimating unit;

the anti-skid controller comprising;

a control parameter setting unit for setting a first control parameter when provision of the assist steering torque by the assist steering torque providing unit is not effected and for setting a second control parameter different from the first control parameter when provision of the assist steering torque by the assist steering torque providing unit is effected; and

a braking force controlling unit for controlling the braking forces to be imposed on the wheels depending on the first control parameter set by the control parameter setting unit and the second control parameter set by the control parameter setting unit.

7. The anti-skid controller as claimed in claim 6,

wherein

the control parameter setting unit is arranged so as to set the first control parameter to be a parameter for reduction control of yaw moment that causes a braking force for one of front wheels of the vehicle to rise slowly with time gradient when anti-skid control begins on the other front wheel;

and

the control parameter setting unit is arranged so as to set the second control parameter to be a parameter having a larger time gradient than the first control parameter or a parameter for inhibiting the reduction control of yaw moment.

8. The anti-skid controller as claimed in claim 6,

wherein

the control parameter setting unit is arranged so as to set the first control parameter to be a select low control parameter for controlling a braking force on one of rear wheels of the vehicle in the same manner as on the other rear wheel when anti-skid begins on the other rear wheel;

and

the control parameter setting unit is arranged so as to set the second control parameter to be a parameter for causing the braking force on the one of the rear wheels to rise with time gradient after a predetermined period of time of select low control.

9. The anti-skid controller as claimed in claim 7, wherein the control parameter setting unit is arranged so as to set the second control parameter when the turning condition of the vehicle is not beyond a predetermined value.

10. The anti-skid controller as claimed in claim 8, wherein the control parameter setting unit is arranged so as to set the second control parameter when the turning condition of the vehicle is not beyond a predetermined value.

11. The anti-skid controller as claimed in claim 6, further comprising a steering direction judging unit for judging a direction of steering by the steering operation;

wherein

the control parameter setting unit is arranged so as to inhibit the setting of the second control parameter when the steering direction judging unit judges that steering is not made in the direction for a counter-steering operation regardless of the fact that a provision of assist steering torque by the assist steering torque providing unit is effected.