Steering Wheel Return Setpoint Adjustment for Acceleration Centering

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Solution Overview

Problem

Existing steering assistance systems in vehicles, particularly those with rear-mounted engines, experience reduced centering efforts during acceleration phases due to dynamic lightening of the front axle, leading to distorted driver feelings and vehicle control.

Innovation Solution

A method that dynamically adjusts the steering wheel return setpoint based on instantaneous longitudinal acceleration, intensifying the return force during increased acceleration to compensate for the reduced centering effect, ensuring continuous and effective centering of the steering wheel and directional train.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the vehicle uses a rear-mounted engine configuration, then the front axle becomes less stressed and steering is less subject to spontaneous centering, but the centering effort is reduced during acceleration phases

Engineering Contradiction:
Improvespontaneous centering tendencyVSAvoidcentering effort during acceleration
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent dynamically changes the recall setpoint parameter based on longitudinal acceleration conditions. During acceleration phases, the recall setpoint is increased to compensate for the reduced natural centering effect caused by rear-engine vehicle dynamics, ensuring consistent steering centering effort across all driving conditions

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements a dynamic control system that continuously monitors longitudinal acceleration and adjusts the recall setpoint in real-time. This dynamic adaptation allows the steering assistance system to compensate for varying front axle loading conditions during acceleration, maintaining reliable centering effort despite changes in vehicle dynamics

Inventive Principle:
Principle #15Dynamics

2Reliability

If the recall setpoint is increased during acceleration to compensate for reduced centering effect, then centering effectiveness is maintained, but system complexity increases

Engineering Contradiction:
Improvecentering effectivenessVSAvoidcontrol system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent utilizes the existing longitudinal acceleration sensor already present in the vehicle for other functions (such as traction control or stability control) and repurposes this data for steering centering compensation. This multi-functional use of existing sensors avoids adding dedicated hardware while achieving the required centering effectiveness during acceleration

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces potential mechanical complexity with electronic control logic. Instead of adding mechanical linkages or physical adjustment mechanisms, the system uses electronic processing of acceleration data and electronic adjustment of the recall setpoint through the existing power steering control unit, simplifying the overall system architecture

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2870051B1Method for centring the steering wheel of a motor vehicle power assisted steering
Publication Date: 2016.12.07 JTEKT EUROPE SAS
  • EP2870051B1 patent drawingFigure 1~2(d)

AI summary

The invention relates to a method to assist with turning a vehicle power assisted steering wheel, during which method a return setpoint (final return setpoint) quantifying a return force intended to be applied to said steering wheel in order to assist with returning said steering wheel to a predetermined central position is formulated, said method involving at least one step (a) of determining longitudinal acceleration during which step the instantaneous longitudinal acceleration of the vehicle is evaluated, followed by a step (b) of adapting the return setpoint during which step the steering wheel return setpoint is adjusted according to said instantaneous longitudinal acceleration so as to increase the intensity of the return force if said longitudinal acceleration increases, and thus notably compensate for the lessening of the natural centring effect that is caused by the lightening of the steering under acceleration conditions.