Steering Assist Device

Patent metadata

Field	Value
Publication number	US-2016362136-A1
Application number	US-201615176843-A
Country	US
Kind code	A1
Filing date	Jun 8, 2016
Priority date	Jun 15, 2015
Publication date	Dec 15, 2016
Grant date	—

Abstract

In a steering assist device, a correction gain setting unit sets correction gain to one if it determines that that the sign of a lateral deviation change rate is different from that of a second derivative value of a lateral deviation. The correction gain setting unit sets the correction gain to a predetermined value that is larger than one, if it determines that that the sign of the lateral deviation change rate is the same as that of the second derivative value of the lateral deviation.
A gain multiplication unit corrects a lane keep assist current value calculated by a lane keep assist current value calculation unit by multiplying the lane keep assist current value by the correction gain set by the correction gain setting unit.

First claim

What is claimed is:

1 . A steering assist device, comprising:
an electric motor that applies a steering driving force to a steering operation mechanism of a vehicle; an information obtaining unit that obtains a lateral deviation of the vehicle from a target travel line, a lateral deviation change rate or a rate of change in the lateral deviation per unit time, and a rate of change in the lateral deviation change rate per unit time; a steering assist current value setting unit that sets a steering assist current value corresponding to a target value of steering assist torque; a lane keep assist current value calculation unit that calculates a lane keep assist current value that makes the lateral deviation and the lateral deviation change rate closer to zero, based on the lateral deviation and the lateral deviation change rate obtained by the information obtaining unit; a correction unit that corrects the lane keep assist current value calculated by the lane keep assist current value calculation unit so that an absolute value of the lane keep assist current value increases, if the lateral deviation change rate and the rate of change in the lateral deviation change rate per unit time obtained by the information obtaining unit have the same sign; a target current value calculation unit that calculates a target current value by using the steering assist current value set by the steering assist current value setting unit and the lane keep assist current value corrected by the correction unit; and a control unit that drivingly controls the electric motor based on the target current value calculated by the target current value calculation unit.

2 . The steering assist device according to claim 1 , wherein
the correction unit corrects the lane keep assist current value calculated by the lane keep assist current value calculation unit by multiplying the lane keep assist current value by correction gain that is larger than one, if the lateral deviation change rate and the rate of change in the lateral deviation change rate per unit time obtained by the information obtaining unit have the same sign.

3 . The steering assist device according to claim 2 , wherein
the correction gain is calculated based on the lateral deviation change rate and the rate of change in the lateral deviation change rate per unit time obtained by the information obtaining unit.

4 . The steering assist device according to claim 1 , wherein
the correction unit corrects the lane keep assist current value calculated by the lane keep assist current value calculation unit by adding a correction value having the same sign as that of the lane keep assist current value to the lane keep assist current value, if the lateral deviation change rate and the rate of change in the lateral deviation change rate per unit time obtained by the information obtaining unit have the same sign.

Assignees

• Jtekt Corp

Inventors

• Oya Toshiaki

Classifications

• B62D15/025 Primary

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

• B62D5/0454

  Worm gears · CPC title

• B60R1/00

  Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles · CPC title

• B62D5/0409

  Electric motor acting on the steering column · CPC title

• B60W30/12 Primary

  Lane keeping · CPC title