Steering Control Device

Patent metadata

Field	Value
Publication number	US-2018093701-A1
Application number	US-201715713016-A
Country	US
Kind code	A1
Filing date	Sep 22, 2017
Priority date	Oct 3, 2016
Publication date	Apr 5, 2018
Grant date	—

Abstract

A steering control device includes a controller configured to execute turning processing of controlling a controlled variable to a command value corresponding to an operation of a steering wheel by controlling a turning-side actuator in a cutoff state, the controlled variable being at least one of a turning angle of the steered wheels and a turning angle rate that is a changing rate of the turning angle; and transmission switching processing of controlling a switching device such that the switching device is switched from the cutoff state to a transmission state on condition that an absolute value of a difference between the controlled variable and the command value continues to be equal to or larger than a threshold when the turning processing is executed.

First claim

What is claimed is:

1 . A steering control device configured to control a steering system including a switching device that is switched between a transmission state and a cutoff state, the transmission state being a state where power is transmitted from a steering wheel to steered wheels, and the cutoff state being a state where transmission of the power from the steering wheel to the steered wheels is cut off; a steering-side actuator configured to apply a steering reaction force to the steering wheel in the cutoff state; and a turning-side actuator configured to turn the steered wheels, the steering control device comprising
a controller configured to execute: turning processing of controlling a controlled variable to a command value corresponding to an operation of the steering wheel by controlling the turning-side actuator in the cutoff state, the controlled variable being at least one of a turning angle of the steered wheels and a turning angle rate that is a changing rate of the turning angle; and transmission switching processing of controlling the switching device such that the switching device is switched from the cutoff state to the transmission state on condition that an absolute value of a difference between the controlled variable and the command value continues to be equal to or larger than a threshold when the turning processing is executed.

2 . The steering control device according to claim 1 , wherein the controller is configured to execute assist processing of assisting in turning of the steered wheels caused by the operation of the steering wheel, with use of at least one of the steering-side actuator and the turning-side actuator in a case where the switching device is switched to the transmission state by the transmission switching processing.

3 . The steering control device according to claim 2 , wherein:
in the turning processing, the turning-side actuator is controlled based on an output value of an integral element obtained by using, as an input, the difference between the controlled variable and the command value; and in the assist processing, in the case where the switching device is switched to the transmission state by the transmission switching processing, a value held by the integral element at a time point at which the switching device is switched to the transmission state is not reflected in control of the turning-side actuator.

4 . The steering control device according to claim 1 , wherein:
in the turning processing, the controlled variable is the turning angle; the controller is configured to execute determination processing of determining whether the absolute value of the difference between the controlled variable and the command value continues to be equal to or larger than the threshold when the turning processing is executed by using, as inputs, a detected value of the turning angle and a command value of the turning angle; and the controller is configured to execute the transmission switching processing based on a result of the determination processing.

5 . The steering control device according to claim 1 , wherein the controller is configured to execute: acquisition processing of acquiring a temperature of one of the steering-side actuator and the turning-side actuator; current limit processing of limiting a current flowing through one of the steering-side actuator and the turning-side actuator in a case where the temperature acquired by the acquisition processing is equal to or higher than a first threshold temperature when the switching device is in the transmission state; and switching processing of controlling the switching device such that the switching device is switched from the cutoff state to the transmission state in a case where the temperature acquired by the acquisition processing is equal to or higher than a second threshold temperature that is lower than the first threshold temperature when the switching device is in the cutoff state.

6 . The steering control device according to claim 5 , wherein:
the acquisition processing is turning-side temperature acquisition processing of acquiring the temperature of the turning-side actuator; and the controller is configured to execute assist processing of controlling at least one of the steering-side actuator and the turning-side actuator to assist in turning of the steered wheels caused by the operation of the steering wheel in a case where the switching device is switched to the transmission state by the switching processing.

7 . The steering control device according to claim 6 , wherein the controller is configured not to use the turning-side actuator in the assist processing in the case where the switching device is switched to the transmission state by the switching processing.

8 . The steering control device according to claim 5 , wherein:
the controller is configured to execute switching temperature acquisition processing of acquiring a temperature of the switching device; the switching device is a normally-closed switching device; the switching processing includes processing of controlling the switching device such that the switching device is switched from the cutoff state to the transmission state in a case where the temperature acquired by the switching temperature acquisition processing is equal to or higher than a specified temperature when the switching device is in the cutoff state; and the controller is configured to execute assist processing of controlling at least one of the steering-side actuator and the turning-side actuator to assist in turning of the steered wheels caused by the operation of the steering wheel in a case where the switching device is switched to the transmission state by the switching processing based on a fact that the temperature acquired by the switching temperature acquisition processing is equal to or higher than the specified temperature.

9 . The steering control device according to claim 5 , wherein:
the acquisition processing is steering-side temperature acquisition processing of acquiring the temperature of the steering-side actuator; and the controller is configured to execute assist processing of controlling at least one of the steering-side actuator and the turning-side actuator to assist in turning of the steered wheels caused by the operation of the steering wheel in a case where the switching device is switched to the transmission state by the switching processing.

10 . The steering control device according to claim 9 , wherein the controller is configured not to use the steering-side actuator in the assist processing in the case where the switching device is switched to the transmission state by the switching processing.

11 . The steering control device according to claim 5 , wherein
the controller is configured to execute:
steering angle command value setting processing of setting a steering angle command value based on the operation of the steering wheel;
steering-side control processing of controlling the steering-side actuator to control a steering angle to the steering angle command value through feedback;
turning angle command value setting processing of setting a turning angle command value based on the operation of the steering wheel;
turning-side control processing of controlling the turning-side actuator to control the turning angle to the turning angle command value through feedback;
variable setting processing of variably setting a command value of a steering angle ratio that is a ratio between the turning angle command value and the steering angle command value when the switching device is in the cutoff state; and
stop processing of stopping variably setting the ratio between the turning angle command

Assignees

• Jtekt Corp

Inventors

• Kodera Takashi

Classifications

• B62D5/0478 Primary

  Clutches · CPC title

• B62D5/001 Primary

  Mechanical components or aspects of steer-by-wire systems, not otherwise provided for in this maingroup · CPC title

• B62D5/003

  Backup systems, e.g. for manual steering (B62D5/30 takes precedence) · CPC title

• B62D6/007

  adjustable by the driver, e.g. sport mode · CPC title

• B62D6/00

  Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits (means for initiating a change in direction B62D1/00; steering valves B62D5/06; combined with means for inclining the vehicle body or wheels on bends B62D9/00) · CPC title