Steering control device and steering system

Patent metadata

Field	Value
Publication number	US-9387876-B2
Application number	US-201514661192-A
Country	US
Kind code	B2
Filing date	Mar 18, 2015
Priority date	Mar 20, 2014
Publication date	Jul 12, 2016
Grant date	Jul 12, 2016

Abstract

A steering system includes a steering angle detection unit that detects a steering angle of a steering wheel; a steering torque detection unit that detects a steering torque with respect to the steering wheel; an ECU that calculates a corrected steering angle by nonlinearly correcting the steering angle, a first steering parameter as the product of an angular velocity of the steering angle and the steering torque, a second steering parameter as the product of the corrected steering angle and a time differential value of the steering torque, and a target control amount based on the first steering parameter and the second steering parameter; and a steering support unit that applies a rotation torque to the steering wheel based on the target control amount.

First claim

What is claimed is:

1. A steering control device comprising:
a steering angle detection unit that detects a steering angle during a steering operation of a steering wheel performed by a driver;
a corrected steering angle calculation unit that calculates a corrected steering angle by nonlinearly correcting the steering angle detected by the steering angle detection unit in accordance with a steering characteristic of a vehicle;
a first steering parameter calculation unit that calculates the product of a steering angular velocity and a steering torque during the steering operation as a first steering parameter;
a second steering parameter calculation unit that calculates the product of the corrected steering angle and a time differential value of the steering torque during the steering operation as a second steering parameter;
a steering power calculation unit that calculates a steering power showing a steering type of the driver with respect to the steering wheel based on the first steering parameter and the second steering parameter; and
a control amount calculation unit that calculates a target control amount of an actuator of a steering device based on the steering power.

2. The steering control device according to claim 1 , wherein
the corrected steering angle calculation unit calculates the corrected steering angle such that an amount of change of the corrected steering angle per unit time with respect to an amount of change of the steering angle per unit time in a case where the absolute value of the steering angle exceeds a first angle is lower than the amount of change of the steering angle per unit time with respect to an amount of change of the steering angle per unit time in a case where the absolute value of the steering angle is equal to or less than the first angle.

3. The steering control device according to claim 1 , wherein
the corrected steering angle calculation unit maintains the corrected steering angle to be constant at the corrected steering angle when the steering angle is a first angle in a case where the absolute value of the steering angle exceeds the first angle.

4. The steering control device according to claim 2 , wherein
the corrected steering angle calculation unit calculates the corrected steering angle such that the amount of change of the corrected steering angle per unit time with respect to the amount of change of the steering angle per unit time in a case where the absolute value of the detected steering angle is equal to or less than a second angle that is smaller than the first angle is smaller than the amount of change of the corrected steering angle per unit time with respect to the amount of change of the steering angle per unit time in a case where the absolute value of the steering angle exceeds the second angle and is equal to or less than the first angle.

5. The steering control device according to claim 1 , wherein
the corrected steering angle calculation unit calculates the corrected steering angle allowing for a change characteristic of a turning angle of a turning wheel with respect to the steering angle or a change characteristic of a turning force to the turning wheel with respect to the steering angle.

6. A steering system comprising:
a steering angle detection unit that detects a steering angle of a steering wheel;
a steering torque detection unit that detects a steering torque with respect to the steering wheel;
an ECU that calculates a corrected steering angle by nonlinearly correcting the steering angle, a first steering parameter as the product of an angular velocity of the steering angle and the steering torque, a second steering parameter as the product of the corrected steering angle and a time differential value of the steering torque, and a target control amount based on the first steering parameter and the second steering parameter; and
a steering support unit that applies a rotation torque to the steering wheel based on the target control amount.

7. The steering system according to claim 6 , wherein
the ECU calculates the corrected steering angle such that an amount of change of the corrected steering angle with respect to an amount of change of the steering angle in a case where the absolute value of the steering angle exceeds a first angle is smaller than the amount of change of the corrected steering angle with respect to the amount of change of the steering angle in a case where the absolute value of the steering angle is equal to or less than the first angle.

Assignees

• Toyota Motor Co Ltd

Inventors

• Kojo Takahiro
• Suzuki Yoshiaki
• Kunihiro Yoji
• Kudo Yoshio
• UEYAMA Masao
• Kimura Yukihide

Classifications

• B62D5/0463 Primary

  calculating assisting torque from the motor based on driver input · 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

• B62D5/04

  electrical, e.g. using an electric servo-motor connected to, or forming part of, the steering gear · CPC title