Control device, electric power steering device, and control method

Patent metadata

Field	Value
Publication number	US-2025010915-A1
Application number	US-202418754625-A
Country	US
Kind code	A1
Filing date	Jun 26, 2024
Priority date	Jun 29, 2023
Publication date	Jan 9, 2025
Grant date	—

Abstract

A control device that controls a steering mechanism mounted on a vehicle includes a first assist controller to execute lane keeping control and generate a first input value. The first assist controller includes a vehicle state calculator to calculate a yaw rate target value and lateral displacement, a yaw rate controller to generate a yaw rate command value based on the yaw rate target value, and a lateral displacement controller to generate a lateral displacement command value based on the lateral displacement. The yaw rate controller includes a yaw rate adjuster to adjust the yaw rate command value according to a frequency. The lateral displacement controller includes a lateral displacement adjuster to adjust the lateral displacement command value according to a frequency.

First claim

What is claimed is:

1 . A control device that controls a steering mechanism mounted on a vehicle, the control device comprising a first assist controller to execute lane keeping control to keep the vehicle in a lane, wherein
the first assist controller includes:
a vehicle state calculator to calculate a yaw rate target value, which is a target value of a yaw rate of the vehicle, and lateral displacement of the vehicle based on input from an imaging device;
a yaw rate controller to generate a yaw rate command value based on the yaw rate target value; and
a lateral displacement controller to generate a lateral displacement command value based on the lateral displacement;
the yaw rate controller includes a yaw rate adjuster to adjust the yaw rate command value according to a frequency; the lateral displacement controller includes a lateral displacement adjuster to adjust the lateral displacement command value according to a frequency; a gain of a transfer function of the yaw rate adjuster in a first frequency band is lower than a gain of the transfer function of the yaw rate adjuster in a second frequency band higher than the first frequency band; and a gain of a transfer function of the lateral displacement adjuster in the second frequency band is lower than a gain of the transfer function of the lateral displacement adjuster in the first frequency band.

2 . The control device according to claim 1 , wherein when the transfer function of the yaw rate adjuster is set to C γ (s), the transfer function of the lateral displacement adjuster is set to C y (s), and a constant that is one or substantially one is set to K γy , C γ (s)=K γy −C y (s) holds.

3 . The control device according to claim 1 , further comprising:
a vehicle stabilization controller to restrict a transfer function of a plant model including an actual steering angle of a tire of the vehicle as input and the yaw rate as output to a transfer function of a nominal model by model following control; wherein the vehicle stabilization controller includes a model following controller to perform model following control; the model following controller is configured or programmed such that the transfer function of the plant model is restricted to the transfer function of the nominal model in a frequency band in which a gain in a gain characteristic of a complementary sensitivity function with respect to a modeling error between the plant model and the nominal model is substantially one; the transfer function of the nominal model includes a parameter corresponding to a natural frequency of the yaw rate; the yaw rate controller includes a yaw rate phase adjuster to adjust a phase of the yaw rate target value; and the transfer function of the yaw rate phase adjuster includes a transfer function by which a parameter corresponding to a natural frequency of the yaw rate in the transfer function of the nominal model can be converted into a different value.

4 . The control device according to claim 1 , further comprising:
a vehicle stabilization controller to restrict a transfer function of a plant model having an actual steering angle of a tire of the vehicle as input and the yaw rate as output to a transfer function of a nominal model by model following control; wherein the vehicle stabilization controller includes a model following controller to perform model following control; the model following controller is configured or programmed such that a transfer function of the plant model is restricted to a transfer function of the nominal model in a frequency band in which a gain in a gain characteristic of a complementary sensitivity function with respect to a modeling error between the plant model and the nominal model is substantially one; the transfer function of the nominal model includes a parameter corresponding to a natural frequency of the yaw rate; and the model following controller configured or programmed to adjust a natural frequency of the yaw rate in the transfer function of the plant model by adjusting a parameter corresponding to the natural frequency of the yaw rate in the transfer function of the nominal model.

5 . The control device according to claim 3 , further comprising:
a second assist controller to generate a second input value input to the vehicle stabilization controller based on a steering input value input from a steering wheel of the vehicle; wherein the first assist controller configured or programmed to generate a first input value; the first input value multiplied by a first gain and the steering input value multiplied by a second gain are input to the second assist controller; the first gain and the second gain are variable values; and when the first gain is K 1 and the second gain is K 2 , K 1 =1−K 2 holds.

6 . The control device according to claim 5 , wherein the first input value multiplied by the first gain is also input to the vehicle stabilization controller.

7 . An electric power steering device comprising:
the control device according to claim 1 ; and the steering mechanism.

8 . A control method of controlling a steering mechanism mounted on a vehicle, the control method comprising executing lane keeping control to keep the vehicle in a lane,
wherein the lane keeping control includes:
calculating a yaw rate target value, which is a target value of a yaw rate of the vehicle, and lateral displacement of the vehicle based on input from an imaging device;
generating a yaw rate command value based on the yaw rate target value;
generating a lateral displacement command value based on the lateral displacement;
adjusting the yaw rate command value according to a frequency in a yaw rate adjuster; and
adjusting the lateral displacement command value according to a frequency in a lateral displacement adjuster;
a gain of a transfer function of the yaw rate adjuster in a first frequency band is lower than a gain of the transfer function of the yaw rate adjuster in a second frequency band higher than the first frequency band; and a gain of a transfer function of the lateral displacement adjuster in the second frequency band is lower than a gain of the transfer function of the lateral displacement adjuster in the first frequency band.

Assignees

• Nidec Corp

Inventors

• Endo Shuji
• Miyake Sohei
• Notsu Daisuke

Classifications

• B60W50/00

  Details of control systems for road vehicle drive control not related to the control of a particular sub-unit {, e.g. process diagnostic or vehicle driver interfaces} · CPC title

• B60W30/12

  Lane keeping · CPC title

• B62D1/20

  Connecting steering column to steering gear · CPC title

• B62D5/0466

  for returning the steering wheel to neutral position · CPC title

• B62D5/0463 Primary

  calculating assisting torque from the motor based on driver input · CPC title