Vehicle steering control apparatus and steering control method

摘要

A vehicle steering control apparatus and vehicle steering control method make it possible to suppress a steering state of a steering operation element from being different from the driver's intention, in starting the driving source. A backup clutch, which is switchable between a release state where a torque transmission path is mechanically decoupled and an engagement state where the torque transmission path is mechanically coupled, is set to the engagement state in starting the engine. When the steering torque detected after the engine starts becomes equal to or lower than a clutch release start torque, the backup clutch in the engagement state is switched to the release state.

主权项

1. A vehicle steering control apparatus, comprising:
a driving source configured to drive a driving wheel; a turning motor configured to turn a turning wheel; a backup clutch configured to be switchable between a release state of mechanically decoupling a torque transmission path between a steering operation element operated by a driver and the turning wheel and an engagement state of mechanically coupling the torque transmission path; a steering torque detector configured to detect a steering torque to be applied to a steering shaft included in the torque transmission path, when the driver operates the steering operation element; a clutch controller configured to set the backup clutch to the engagement state at a time when starting the driving source, and to switch the backup clutch in the engagement state to the release state when the steering torque detected by the steering torque detector after the driving source starts becomes equal to or lower than a clutch release start torque that is set beforehand, and to determine that shifting from the engagement state of the backup clutch to the release state is completed, when the steering torque detected by the steering torque detector is equal to or lower than a predefined clutch release estimate torque which is lower than the clutch release start torque, and when an elapsed time while the steering torque is equal to or lower than the predefined clutch release estimate torque is equal to or longer than a predefined SBW switch determination time, by which it is estimated that the backup clutch is completely shifted to the release state after switching of the engagement state of the backup clutch to the release state starts; and a turning motor controller configured to make the turning motor output a turning assistance torque for assisting turning of the turning wheel in response to an operation of the steering operation element, when the clutch controller sets the backup clutch to the engagement state, and configured to make the turning motor output the turning torque depending on a target turning angle in response to the operation of the steering operation element, when the clutch controller switches the backup clutch in the engagement state to the release state, wherein the turning motor controller is configured to make the turning motor output the turning assistance torque for assisting the turning of the turning wheel in response to the operation of the steering operation element until the clutch controller determines that the shifting from the engagement state of the backup clutch to the release state is completed, and to output the turning torque depending on the target turning angle to control driving of the turning motor, when the clutch controller determines that the shifting from the engagement state of the backup clutch to the release state is completed.