Steering control apparatus

Patent metadata

Field	Value
Publication number	US-10099722-B2
Application number	US-201615292505-A
Country	US
Kind code	B2
Filing date	Oct 13, 2016
Priority date	Oct 27, 2015
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

A steering control apparatus is provided which suppresses possible vibration of a steering system resulting from differential steering processing when a steering angle or a steered angle has a large value. A differential steering processing circuit calculates a differential steering correction amount based on a difference value of a target steering angle, and increases or reduces the target steering angle using the calculated amount to obtain a target steered angle. A limiting reaction force setting processing circuit increases a limiting reaction force when a maximum value of the target steering angle and the target steered angle is equal to or larger than a common threshold. When the maximum value approaches the common threshold, an angle-sensitive gain setting processing circuit reduces an angle-sensitive gain so as to correct and reduce the differential steering correction amount.

First claim

What is claimed is:

1. A steering control apparatus that outputs an operation signal to a steering system, the steering control apparatus comprising:
a central processor operatively communicating with the steering system to control a steering operation actuator and a reaction force actuator, the central processor being configured to:
transmit the operation signal to the steering system, the operation signal causing the steering system to steer steered wheels of a vehicle, in accordance with an operation of a steering wheel;
increase or decrease an amount of steering operation performed by the steering system on the steered wheels due to the operation signal, the amount of steering operation being increased or decreased according to a variation speed of a steering angle due to the operation of the steering wheel causing the steering angle to vary, which is a rotation angle of the steering wheel, the increase or decrease of the steering operation being performed by adding a correction amount of a force to the amount of steering operation in a direction of the variation speed of the steering angle; and

limit the increase or decrease of the steering operation in response to at least one of the steered angle of the steered wheels and the steering angle reaching a predetermined threshold value, such that fluctuations in the increase or decrease of the steering operation is limited at predetermined values of at least one of the steered angle of the steered wheels and the steering angle, which reduces vibration in the steering system.

2. The steering control apparatus according to claim 1 , wherein the processor is configured to:
limit the increase or decrease of the steering operation when at least the steered angle reaches a steered angle threshold,
set a target steered angle that is a target value of the steered angle in accordance with operation of the steering wheel, and output an operation signal to the steering operation actuator in order to controllably adjust the steered angle to the target steered angle, and
correct a magnitude of the target steered angle by increasing or decreasing the magnitude according to the variation speed of the steering angle.

3. The steering control apparatus according to claim 2 , wherein the processor is configured to:
controllably increase a reaction force that is a force resisting operation of the steering wheel by outputting an operation signal to the steering system when the steered angle is equal to or larger than the steered angle threshold, and
based on one of: (i) the corrected target steered angle, (ii) the target steered angle, and (iii) a detection value of the steered angle, perform increase control on the reaction force and limit the increase or decrease of the amount of steering operation.

4. The steering control apparatus according to claim 3 , wherein:
the reaction force actuator applies the reaction force resisting operation of the steering wheel to the steering wheel,
the steering operation actuator applies a force that steers the steered wheels at least during a state in which power transmission between the steering wheel and the steered wheels is blocked, and
the processor is configured to:
limit a limiting reaction force to a value larger than zero when the steered angle is equal to or larger than the steered angle threshold,
set a target steering angle that is a target angle of the steering angle based on the set limiting reaction force, and
control the reaction force actuator in order to perform feedback control for causing the detection value of the steering angle to be adjusted to the target steering angle.

5. The steering control apparatus according to claim 2 , wherein the processor is configured to:
calculate a correction amount by which the target steered angle is corrected according to the variation speed of the steering angle, and
correct and decrease a magnitude of the correction amount to limit the increase or decrease of the amount of steering operation when the steered angle reaches the steered angle threshold, and correct and decrease the magnitude of the correction amount when deviation of the steered angle with reference to a neutral position is equal to or smaller than a specified amount.

6. The steering control apparatus according to claim 1 , wherein the processor is configured to:
limit the increase or decrease of the steering operation when at least the steering angle reaches a steering angle threshold,
set a target steered angle that is a target value of the steered angle in accordance with operation of the steering wheel, and output an operation signal to the steering operation actuator in order to controllably adjust the steered angle to the target steered angle, and
correct the magnitude of the target steered angle by increasing or decreasing the magnitude according to the variation speed of the steering angle.

7. The steering control apparatus according to claim 6 , wherein the processor is configured to:
controllably increase a reaction force that is a force resisting operation of the steering wheel by outputting an operation signal to the steering system when the steering angle is equal to or larger than the steering angle threshold,
limit the increase or decrease of the amount of steering operation when the steering angle reaches the steering angle threshold, and
based on a detection value of the steering angle, increase the reaction force, and limit the increase or decrease of the amount of steering operation.

8. The steering control apparatus according to claim 6 , wherein:
the processor is configured to controllably increase a reaction force that is a force resisting operation of the steering wheel by outputting an operation signal to the steering system when the steering angle is equal to or larger than the steering angle threshold,
the reaction force actuator applies a reaction force resisting operation of the steering wheel to the steering wheel,
the steering operation actuator applies a force that steers the steered wheels at least during a state in which power transmission between the steering wheel and the steered wheels is blocked, and
the processor is configured to:
set a limiting reaction force to a value larger than zero when the steering angle is equal to or larger than the steering angle threshold,
set a target steering angle that is a target angle of the steering angle based on the set limiting reaction force,
control the reaction force actuator in order to controllably adjust a detection value of the steering angle to the target steering angle, and
based on the target steering angle, increase the reaction force, and limit the increase or decrease of the amount of steering operation.

9. The steering control apparatus according to claim 6 , wherein the processor is configured to:
calculate a correction amount by which the target steered angle is corrected according to the variation speed of the steering angle,
correct and decrease a magnitude of the correction amount as processing for limiting the increase or decrease of the amount of steering operation when the steering angle reaches the steering angle threshold, and
correct and decrease the magnitude of the correction amount when deviation of the steering angle with respect to a neutral position is equal to or smaller than a prescribed amount.

10. The steering control apparatus according to claim 1 , wherein the processor is configured to:
correct and decrease the magnitude of an amount of increase or decrease in the amount of steering operation,
gradually increase a decreased correction amount that is an amount by which the amount of increase or decrease is corrected and decreased as at least one of the steered angle an

Assignees

• Jtekt Corp

Inventors

• Kodera Takashi
• Yamano Naoki
• Itamoto Hidenori
• Yamashita Yoshihiro
• Anraku Koji

Classifications

• B62D5/008

  Changing the transfer ratio between the steering wheel and the steering gear by variable supply of energy, e.g. by using a superposition gear · CPC title

• B62D6/002 Primary

  computing target steering angles for front or rear wheels (B62D7/159 takes precedence) · CPC title

• B62D6/008

  Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications · CPC title

• B62D5/0472

  for damping vibrations · CPC title

• B62D5/046 Primary

  Controlling the motor · CPC title