Vehicle Control Method for Turning Performance During Deceleration

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Solution Overview

Problem

Conventional vehicle posture control methods fail to improve turning performance during deceleration, as the vehicle front portion's suspension rigidity increases, leading to insufficient lowering and reduced turning capability.

Innovation Solution

The method involves increasing deceleration during vehicle posture control when the steering system is turned, with higher deceleration applied when the brake pedal is depressed more and when the vehicle is decelerating, to enhance yaw rate generation and improve turning performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If deceleration is added to the vehicle during turning operation to control vehicle posture, then vehicle turning performance is improved, but during deceleration the vehicle front portion is already lowered and suspension rigidity is increased, causing insufficient lowering effect and reduced turning capability

Engineering Contradiction:
Improvevehicle turning performanceVSAvoidsuspension rigidity
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The control device adds deceleration to the vehicle before the turning operation is completed, when the steering wheel angle is increasing. This preliminary deceleration action lowers the vehicle front portion in advance, creating space for the subsequent lowering effect during turning, thereby preventing the insufficiency that would occur if deceleration were applied only after the vehicle was already decelerating

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control device dynamically adjusts the deceleration amount based on the vehicle's current deceleration state. When the vehicle is already decelerating, the control device reduces or stops adding deceleration to avoid excessive suspension compression and maintain effective vehicle posture control. This dynamic adjustment ensures optimal turning performance across varying deceleration conditions

Inventive Principle:
Principle #15Dynamics

2Speed

If deceleration is increased to promptly generate yaw rate during turning, then steering responsiveness is improved, but excessive deceleration during already-decelerating vehicle causes insufficient lowering due to increased suspension rigidity

Engineering Contradiction:
Improveyaw rate generation speedVSAvoidturning capability
Core Design Contradiction:
SpeedVSEase of operation

Solution Approach 1:

The control device applies deceleration in advance when the steering wheel angle is increasing, before the vehicle enters a decelerated state. This preliminary action ensures the vehicle front portion is lowered when there is still sufficient suspension compliance, enabling effective yaw rate generation without the limitation of increased suspension rigidity

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control device changes the deceleration parameter dynamically based on the vehicle's current state. When the vehicle is already decelerating, the control device reduces the deceleration amount to maintain suspension flexibility and ensuring continued effectiveness of the lowering action for improving turning capability

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3738816B1Vehicle control method, and control device for vehicle system and vehicle
Publication Date: 2022.12.07 MAZDA MOTOR CORP
  • EP3738816B1 patent drawingFigure 1
  • EP3738816B1 patent drawingFigure 2
  • EP3738816B1 patent drawingFigure 3~4

AI summary

A control method for a vehicle has: a step of determining whether a turning operation of a steering system including a steering wheel 6 and the like is performed on the basis of a steering angle that is detected by a steering angle sensor 8; a step of causing a motor generator 4 to generate regenerative power and adding deceleration to a vehicle 1 so as to control a vehicle posture when it is determined that the turning operation of the steering system is performed; and a step of increasing the deceleration, which is added to the vehicle 1 in order to control the vehicle posture, to be higher when the deceleration generated on the vehicle 1 has a first value than when the deceleration generated on the vehicle 1 has a second value that is lower than the first value.