Vehicle Braking Force Control for Steered Start Stability

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing vehicle braking force controlling systems fail to enhance turning capability and stability during steered starts, especially on low-friction surfaces, while maintaining the braking force keeping function and avoiding driver discomfort from dragging sensations and abnormal noise.

Innovation Solution

A vehicle braking force controlling apparatus that detects steered starts and applies braking force to the turning inner front wheel and outer rear wheel, with a controller managing braking force distribution based on steering angle, accelerator position, and pedal speed to improve yaw moment and prevent slip, while maintaining the braking force keeping function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If braking force is applied to the turning inner rear wheel to improve turning performance, then turning capability is improved, but driver discomfort (sense of dragging and abnormal noise) increases

Engineering Contradiction:

Improveturning capabilityVSAvoiddriver discomfort

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent segments the braking force application by wheel position, applying braking force to the turning inner front wheel and turning outer rear wheel instead of the conventional turning inner rear wheel. This segmentation allows independent control of braking forces on different wheels to achieve both turning improvement and noise reduction

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies different braking force characteristics to different wheels based on their specific roles during steered start. The turning inner front wheel receives braking force to improve turning capability, while the turning outer rear wheel receives braking force to suppress abnormal noise and prevent drive slip, creating local quality differences in braking application

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If braking force is reduced upon start to suppress abnormal noise, then abnormal noise is reduced, but turning-round capability deteriorates

Engineering Contradiction:

Improveabnormal noiseVSAvoidturning-round capability

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

Instead of uniformly reducing braking force across all wheels, the patent segments braking force application by applying it selectively to specific wheels (turning inner front wheel and turning outer rear wheel) with different characteristics, maintaining turning capability while suppressing noise

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameters of braking force application by selecting specific wheels and adjusting braking force magnitude and timing differently for each wheel based on steering angle, vehicle speed, and accelerator position, achieving noise suppression without sacrificing turning capability

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If braking force keeping function is active during transition from stopped to start state, then vehicle stability is improved, but application of conventional turning brake control becomes inapplicable

Engineering Contradiction:

Improvevehicle stabilityVSAvoidcontrol applicability

Core Design Contradiction:

Stability of the object's compositionVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic control by detecting steered start conditions and dynamically adjusting braking force application based on real-time parameters such as steering angle, vehicle speed, and accelerator position, allowing the system to adapt to changing conditions while maintaining vehicle stability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms by continuously monitoring vehicle state parameters (steering angle, vehicle speed, accelerator position) and using this information to control braking force application, ensuring the braking control works effectively with the braking force keeping function active

Inventive Principle:

Principle #23Feedback

4Reliability

If braking force is applied to rear wheel to prevent drive slip, then drive slip prevention is improved, but turning capability may be compromised

Engineering Contradiction:

Improvedrive slip preventionVSAvoidturning capability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies braking force to the turning outer rear wheel specifically to prevent drive slip during steered start, while simultaneously applying braking force to the turning inner front wheel to maintain turning capability. Each wheel receives braking force with locally optimized characteristics for its specific function

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS10220821B2Vehicle braking force controlling apparatus

Publication Date: 2019.03.05 SUBARU CORP

AI summary

A vehicle braking force controlling apparatus includes a steered start detector and a controller. The steered start detector detects steered start of a vehicle on a basis of a driving state of the vehicle. The vehicle has a plurality of wheels. The steered start is start of the vehicle in which steering is performed. The controller applies braking force to a turning inner front wheel and braking force to a turning outer rear wheel when the steered start of the vehicle is detected by the steered start detector. The turning inner front wheel is a front wheel of the plurality of wheels which is located on inner side upon turning of the vehicle. The turning outer rear wheel is a rear wheel of the plurality of wheels which is located on outer side upon the turning of the vehicle.