Vehicle Motion Control Device for Sideslip Prevention

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing vehicle motion control systems fail to reliably reduce sideslip in critical driving regions without causing an unnatural feel, and they often require excessive deceleration to correct understeer, which can lead to reduced effectiveness and an unnatural driving experience.

Innovation Solution

A vehicle motion control system that independently controls the driving and braking forces of four wheels, switching between two modes: one for coordinated longitudinal acceleration/deceleration with lateral motion, and another for differential braking/acceleration based on sideslip information to generate a yaw moment, ensuring effective sideslip prevention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If differential braking forces are applied to generate yaw moment for sideslip prevention, then vehicle stability is improved, but driving naturalness deteriorates

Engineering Contradiction:
Improvesideslip prevention effectivenessVSAvoiddriving naturalness
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The control system dynamically switches between two modes: a first mode for normal coordinated acceleration/deceleration control, and a second mode for differential braking control when sideslip occurs. This dynamic adaptation allows the system to provide strong intervention only when necessary, maintaining natural driving feel during normal operation while ensuring safety during critical situations

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses a phase plane model that replicates expert driver behavior patterns. By copying the coordinated control strategy that expert drivers naturally employ, the system achieves both sideslip prevention and natural driving feel without requiring aggressive differential braking

Inventive Principle:
Principle #26Copying

2Reliability

If excessive deceleration is applied to correct understeer, then vehicle stability is improved, but control effectiveness deteriorates

Engineering Contradiction:
Improveundersteer correction capabilityVSAvoidcontrol effectiveness
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system changes the control parameter from simple deceleration amount to phase plane position (combining sideslip angle and yaw rate). By detecting the vehicle's state in the phase plane, the system can apply precise, minimal intervention rather than excessive deceleration, improving both stability and control effectiveness

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system continuously monitors vehicle state through phase plane detection and provides feedback-based control. This allows the system to apply only the necessary correction force to address understeer, avoiding over-correction and maintaining optimal control effectiveness

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2484572B1Vehicle motion control device
Publication Date: 2017.07.05 HITACHI AUTOMOTIVE SYST LTD
  • EP2484572B1 patent drawingFigure 1
  • EP2484572B1 patent drawingFigure 2~3
  • EP2484572B1 patent drawingFigure 4

AI summary

There is provided a vehicle drive control system that feels less unnatural and that enables an improvement in safety performance. A vehicle motion control system capable of independently controlling a driving force and a braking force of four wheels comprises: a first mode (G-Vectoring control) in which substantially the same driving force and braking force are generated with respect to left and right wheels among the four wheels based on a longitudinal acceleration/deceleration control command that is coordinated with the vehicle's lateral motion; and a second mode (sideslip prevention control) in which different driving forces and braking forces are generated with respect to the left and right wheels among the four wheels based on a target yaw moment derived from the vehicle's sideslip information, wherein the first mode is selected when the target yaw moment is equal to or less than a pre-defined threshold, and the second mode is selected when the target yaw moment is greater than the threshold (Figure 11).