Integrated control system for vehicle

Patent metadata

Field	Value
Publication number	US-11260840-B2
Application number	US-201916254013-A
Country	US
Kind code	B2
Filing date	Jan 22, 2019
Priority date	Oct 29, 2018
Publication date	Mar 1, 2022
Grant date	Mar 1, 2022

Abstract

An integrated control system for a vehicle is provided. The system includes a friction coefficient calculation unit that calculates friction coefficients of left side and right side road surfaces, respectively, based on vehicle wheel state information and a predetermined setting information collected during ABS operation. A feedforward braking pressure calculation unit calculates a feedforward braking pressure of each vehicle wheel using the friction coefficients. An ABS braking pressure calculation unit calculates an ABS braking pressure of the each vehicle wheel based on the feedforward braking pressure and slip rate information. A rear wheel steering control amount calculation unit calculates a rear wheel steering control amount for yaw compensation using the ABS braking pressure of each vehicle wheel and a rear wheel steering controller executes a rear wheel steering control according to the rear wheel steering control amount.

First claim

What is claimed is:

1. An integrated control system for a vehicle, comprising:
a friction coefficient calculation unit configured to calculate a friction coefficient of a left side road surface and a right side road surface, respectively, on which a left side wheel and a right side wheel are grounded in a road surface based on vehicle wheel state information and a predetermined setting information collected from the vehicle upon anti-lock brake system (ABS) operation;
a feedforward braking pressure calculation unit configured to calculate a feedforward braking pressure of each vehicle wheel using the calculated friction coefficients of the left side road surface and the right side road surface;
an ABS braking pressure calculation unit configured to calculate an ABS braking pressure of the each vehicle wheel based on the calculated feedforward braking pressure and information of the vehicle wheel;
a rear wheel steering control amount calculation unit configured to calculate a rear wheel steering control amount for yaw compensation using the calculated ABS braking pressure of each vehicle wheel; and
a rear wheel steering controller configured to perform a rear wheel steering control of the vehicle based on the calculated rear wheel steering control amount,
wherein the feed forward braking pressure calculation unit is configured to calculate a limit braking pressure using the calculated friction coefficient, and add or subtract the braking pressure for compensating a slip rate of each vehicle wheel within the calculated limit braking pressure to mitigate chattering,
wherein the friction coefficient calculation unit includes a friction coefficient convergence section configured to calculate the friction coefficient of the left side road surface and the right side road surface using the longitudinal force based left side road surface friction coefficient, the longitudinal force based right side road surface friction coefficient, and the lateral force based on the calculated road surface friction coefficient, and
wherein the friction coefficient convergence section is configured to:

calculate the current friction coefficient of the left side road surface and the current friction coefficient of the right side road surface using the longitudinal force based left side road surface friction coefficient, the longitudinal force based right side road surface friction coefficient, the lateral force based road surface friction coefficient, the weighting factors, and the friction coefficient determined in the previous control cycle using the following E1 and E2,
μ FL ( k )= w Lat_FL μ Lat +w Long_FL μ Long_FL +(1− w Lat_FL −w Long_FL )μ FL ( k− 1)  E1

μ FR ( k )= w Lat_FR μ Lat +w Long_FR μ Long_FR +(1− w Lat_FR −w Long_FR )μ FR ( k− 1)  E2

wherein, μ FL (k) refers to the current friction coefficient of the left side road surface, μ FR (k) to the current friction coefficient of the right side road surface, μ FL (k−1) to the friction coefficient of the left side road surface determined in the previous control cycle, μ FR (k−1) to the friction coefficient of the right side road surface determined in the previous control cycle, w Lat_FL to the left side wheel lateral weighting factor, μ Lat to the lateral force based road surface friction coefficient, w Long_FL to the left side wheel longitudinal weighting factor, μ Long_FL to the longitudinal force based left side road surface friction coefficient, w Lat_FR to the right side wheel lateral weighting factor, w Long_FR to the right side wheel longitudinal weighting factor, and μ Long_FR to the longitudinal force based right side road surface friction coefficient.

2. The integrated control system for the vehicle of claim 1 , wherein the friction coefficient calculation unit further includes:
a tire force calculation section configured to predict and calculate a tire force of the left side wheel and a tire force of the right side wheel for each road surface friction coefficient using a predetermined tire model for each road surface friction coefficient from the vehicle wheel state information, respectively; and
a friction coefficient estimation section configured to calculate a longitudinal force based left side road surface friction coefficient, a longitudinal force based right side road surface friction coefficient, and a lateral force based road surface friction coefficient from the tire force of the left side wheel and the right side wheel for each predicted road surface friction coefficient, and the estimated longitudinal and lateral tire force.

3. The integrated control system for the vehicle of claim 2 , wherein the tire force calculation section includes:
a left side tire force calculation section configured to calculate the tire force of the left side wheel in a front side wheel of the vehicle for each road surface friction coefficient using the predetermined tire model for the each road surface friction coefficient; and
a right side tire force calculation section configured to calculate the tire force of the right side wheel in the front side wheel of the vehicle for each road surface friction coefficient using the predetermined tire model for the each road surface friction coefficient.

4. The integrated control system for the vehicle of claim 2 , wherein the tire force calculation section is configured to calculate the longitudinal tire force and the lateral tire force for each road surface friction coefficient of the corresponding wheel, respectively, as the tire force of the left side wheel and the tire force of the right side wheel.

5. The integrated control system for the vehicle of claim 4 , wherein the estimated longitudinal tire force used in the friction coefficient estimation section includes the longitudinal tire force of the left side wheel and the right side wheel in the front side wheel of the vehicle.

6. The integrated control system for the vehicle of claim 5 , wherein the friction coefficient estimation section includes:
a first longitudinal force based friction coefficient estimation section configured to calculate the longitudinal force based left side road surface friction coefficient using the longitudinal tire force of the left side wheel for each road surface friction coefficient and the estimated longitudinal tire force of the left side wheel;
a second longitudinal force based friction coefficient estimation section configured to calculate the longitudinal force based right side road surface friction coefficient using the longitudinal tire force of the right side wheel for each road surface friction coefficient and the estimated longitudinal tire force of the right side wheel; and
a lateral force based friction coefficient estimation section configured to calculate the lateral force based road surface friction coefficient using the lateral tire force of the left side wheel for each road surface friction coefficient, the lateral tire force of the right side wheel for each road surface friction coefficient, and the estimated lateral tire force.

7. The integrated control system for the vehicle of claim 6 , wherein the first longitudinal force based friction coefficient estimation section is configured to:
determine a weighting factor for each road surface friction coefficient using a predetermined equation from the longitudinal tire force of the left side wheel for each road surface friction coefficient and the estimated longitudinal tire force of the left side wheel; and
calculate the longitudinal force based left side road surface friction coefficient by multiplying each road surface friction coefficient of the predetermined tire model by the determined weighting factor for each road surface friction coefficient and summing them.

8. The integ

Assignees

• Hyundai Motor Co Ltd
• Kia Motors Corp

Inventors

• Cho Wan Ki

Classifications

• B60W40/114

  Yaw movement · CPC title

• B60W10/20

  including control of steering systems · CPC title

• B60T2210/124

  Roads with different friction levels · CPC title

• B60T2260/022

  Rear-wheel steering; Four-wheel steering · CPC title

• B60W30/02 Primary

  Control of vehicle driving stability · CPC title