Vehicle Control Braking Force Gradient Adjustment

Solution Overview

Problem

Existing vehicle control systems experience abrupt braking force reductions during behavior stabilization control, leading to uncomfortable sensations for drivers, especially when transitioning from oversteer control or on low-friction surfaces, and can result in delayed control termination and unnecessary continued intervention.

Innovation Solution

A vehicle control system that includes a reduction gradient setting module for braking force, based on steering angle and road surface friction coefficient, to smoothly end behavior stabilization control, thereby reducing driver discomfort and ensuring timely control termination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the braking force is reduced in one breath when ending the behavior stabilization control, then the control termination is quick, but the driver feels the sensation of abruptness

Engineering Contradiction:

Improvecontrol termination timeVSAvoiddriver sensation of abruptness

Core Design Contradiction:

Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making the braking force reduction gradient variable rather than fixed. The control ECU dynamically adjusts the reduction gradient based on real-time steering angle and road surface friction coefficient, allowing the system to optimize between quick termination and comfort based on current driving conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of braking force reduction gradient based on steering angle and road surface friction coefficient. By modifying this parameter according to driving conditions, the system achieves both quick control termination when appropriate and reduced abruptness sensation when needed

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If the braking force is reduced gradually when ending the behavior stabilization control, then the driver does not feel the sensation of abruptness, but the control termination is delayed

Engineering Contradiction:

Improvedriver sensation of abruptnessVSAvoidcontrol termination time

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The system dynamically adjusts the braking force reduction gradient based on real-time steering angle and road surface friction coefficient, allowing optimization between comfort and speed of termination based on current driving conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control ECU modifies the braking force reduction gradient parameter according to steering angle and road surface friction coefficient, achieving both quick control termination when appropriate and reduced abruptness sensation when needed

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If the behavior stabilization control continues unnecessarily, then the driver does not feel abruptness, but the control involvement is unnecessary

Engineering Contradiction:

Improvedriver sensation of abruptnessVSAvoidcontrol efficiency

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The system dynamically adjusts the braking force reduction gradient based on real-time steering angle and road surface friction coefficient, allowing optimization between comfort and speed of termination based on current driving conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control ECU modifies the braking force reduction gradient parameter according to steering angle and road surface friction coefficient, achieving both quick control termination when appropriate and reduced abruptness sensation when needed

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS9592803B2Vehicle control system

Publication Date: 2017.03.14 AUTOLIV NISSIN BRAKE SYST JAPAN CO LTD

AI summary

There is provided a vehicle control system. The vehicle control system includes a steering angle acquiring module, a yaw rate acquiring module that acquires a yaw rate, and a road surface friction coefficient estimation module. The vehicle control system further includes a behavior stabilization control module and a reduction gradient setting module. The behavior stabilization control module executes a behavior stabilization control to exert a braking force on a wheel brake when a vehicle is turning to thereby reduce a deviation between the yaw rate and a target yaw rate. And, the reduction gradient setting module sets a reduction gradient of the braking force when the behavior stabilization control is to be ended, based on the steering angle and the road surface friction coefficient.