Steering control device and electric power steering device

Patent metadata

Field	Value
Publication number	US-12384452-B2
Application number	US-202217840732-A
Country	US
Kind code	B2
Filing date	Jun 15, 2022
Priority date	Jul 29, 2021
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

A steering control device that controls steering of a vehicle in which automatic driving or driving assistance is performed includes a reference steering angle calculation unit that calculates a reference steering angle of the vehicle based on a target steering angle and a vehicle speed of the vehicle, and a compensation unit that determines whether a deviation between the calculated reference steering angle and the target steering angle is equal to or greater than a predetermined value, and when determination is made that the deviation is equal to or greater than the predetermined value, compensates for the calculated reference steering angle such that the calculated reference steering angle follows the target steering angle.

First claim

What is claimed is:

1. A steering control device that controls steering of a vehicle in which automatic driving or driving assistance is performed, the steering control device comprising:
an electronic control unit (ECU) that includes a processor configured to:
calculate a friction torque value to be compensated for a steering mechanism of the vehicle based on a predetermined category of parameters indicating a state of the vehicle including a vehicle speed and a target steering angle, wherein the friction torque value is set to zero when the vehicle speed V is zero,
wherein the friction torque value to be compensated when the vehicle speed is a first vehicle speed value is smaller than the friction torque value to be compensated when the vehicle speed is a second vehicle speed value that is smaller than the first vehicle speed value,
wherein the friction torque value to be compensated when the target steering angle is a first target steering angle is smaller than the friction torque value to be compensated when the target steering angle is a second target steering angle that is larger than the first target steering angle;
calculate a reference steering angle of the vehicle based on the target steering angle and the calculated friction torque value;
determine whether a deviation between the calculated reference steering angle and the target steering angle is equal to or greater than a predetermined value; and
when determination is made that the deviation is equal to or greater than the predetermined value, compensate for the calculated reference steering angle such that the calculated reference steering angle follows the target steering angle.

2. The steering control device according to claim 1 , wherein, as compensation for the calculated reference steering angle, the ECU changes the reference steering angle in a direction in which an absolute value of the deviation between the calculated reference steering angle and the target steering angle decreases when the absolute value of the deviation is greater than a deviation upper limit value set based on the calculated friction torque value, and does not change the reference steering angle when the absolute value of the deviation is not greater than the deviation upper limit value.

3. The steering control device according to claim 1 , wherein the ECU calculates, as the compensation for the calculated reference steering angle, a friction compensation control amount by multiplying the deviation between the calculated reference steering angle and the target steering angle by a gain.

4. The steering control device according to claim 3 , further comprising a low-pass filter that performs a low-pass filter process on the calculated friction compensation control amount.

5. The steering control device according to claim 3 , wherein, as the compensation for the calculated reference steering angle, the ECU:
sets a deviation upper limit value by dividing the calculated friction torque value by the gain;
when a deviation obtained by subtracting the calculated reference steering angle from the target steering angle is greater than the set deviation upper limit value, changes the calculated reference steering angle to a value obtained by subtracting the set deviation upper limit value from the target steering angle;
when the subtracted deviation is smaller than a negative value of the set deviation upper limit value, changes the calculated reference steering angle to a value obtained by adding the set deviation upper limit value to the target steering angle; and
when an absolute value of the subtracted deviation is equal to or smaller than the set deviation upper limit value, maintains the calculated reference steering angle unchanged.

6. The steering control device according to claim 1 , wherein the ECU is further configured to:
calculate a target torque based on the target steering angle; and
output a compensated target torque to an electric actuator of a steering mechanism of the vehicle by adding a friction compensation control amount calculated corresponding to the compensated reference steering angle to the calculated target torque.

7. An electric power steering device comprising:
the steering control device according to claim 1 ; and
an electric actuator of which required torque is controlled based on the compensated reference steering angle.

8. The steering control device according to claim 1 , wherein the calculation of the friction torque value to be compensated is further based on a steering torque output from a torque sensor of a steering wheel of the vehicle, and
the friction torque value to be compensated when the steering torque is a first steering torque is smaller than the friction torque value to be compensated when the steering torque is a second steering torque that is larger than the first steering torque.

Assignees

• Toyota Motor Co Ltd

Inventors

• Ito Ryosuke
• Masumoto Ryusuke
• Ono Kimiaki
• Yoshino Hayato

Classifications

• B62D6/008

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

• B62D15/025

  Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation (B62D1/28 takes precedence) · CPC title

• B62D6/002 Primary

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