Power Steering Torque Control Across Drive Wheel Modes

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Solution Overview

Problem

Existing power steering systems lack flexibility in providing power assisted steering torque, failing to meet the diverse requirements of different driving scenarios.

Innovation Solution

A power steering method and device that dynamically adjust power assisted gear positions based on whether the direction changing wheel is a driving wheel, allowing for varying power steering torques in two-wheel, first all-wheel, and second all-wheel drive modes, with further adjustments through sub-gear positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the power assisted steering torque is kept unchangeable in existing EPS systems, then the system structure remains simple, but the system lacks flexibility to meet different application requirements for various scenarios

Engineering Contradiction:
Improveflexibility to meet different application requirementsVSAvoidsystem structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic adjustment of power assisted steering torque by introducing multiple gear positions (first, second, and third gear positions) that correspond to different driving modes (two-wheel drive, first all-wheel drive with unlocked differential, second all-wheel drive with locked differential). The EPS system automatically switches between these gear positions based on the detected driving mode, making the steering torque dynamic rather than fixed, thereby resolving the contradiction between adaptability and structural simplicity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of power assisted steering torque by associating different gear positions with different torque characteristics. The first gear position provides lower torque for two-wheel drive mode, while the second and third gear positions provide progressively higher torque for all-wheel drive modes. This parameter change enables the system to adapt to different driving scenarios without requiring a completely new system architecture

Inventive Principle:
Principle #35Parameter changes

2Force

If the power steering torque is increased for all-wheel drive modes, then the steering assistance is improved for driving wheels, but the system cannot provide appropriate torque for non-driving wheels in two-wheel drive mode

Engineering Contradiction:
Improvepower steering torqueVSAvoidadaptability to different drive modes
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by providing different power assisted steering torque characteristics for different driving modes. In two-wheel drive mode where the direction changing wheel is not a driving wheel, the system uses the first gear position with lower torque. In all-wheel drive modes where the direction changing wheel is a driving wheel, the system switches to second or third gear positions with higher torque. This localized adaptation of torque characteristics to specific operational conditions resolves the contradiction between providing sufficient torque and maintaining adaptability

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the power steering assembly uses a fixed gear position, then the device complexity is reduced, but the user experience and ride comfort cannot be optimized for different driving conditions

Engineering Contradiction:
Improveuser experience and ride comfortVSAvoidgear position control system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements self-service by enabling the power steering assembly to automatically detect the driving mode (two-wheel drive or all-wheel drive with locked/unlocked differentials) and autonomously switch between different gear positions without requiring manual intervention from the user. The control system monitors vehicle operating conditions and adjusts the steering torque accordingly, thereby optimizing user experience and ride comfort while maintaining relatively simple operation

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3925861B1Power steering method and device, vehicle, and computer storage medium
Publication Date: 2026.03.25 SEGWAY TECH CO LTD
  • EP3925861B1 patent drawingFigure 1~2
  • EP3925861B1 patent drawingFigure 3~4
  • EP3925861B1 patent drawingFigure 5

AI summary

Provided are a power steering method and a power steering device applied in a vehicle including a power steering assembly. The method includes detecting whether a direction changing wheel of the vehicle is a driving wheel; determining a power assisted gear position of the power steering assembly according to whether the direction changing wheel of the vehicle is the driving wheel; and controlling the power steering assembly to generate a power steering torque according to the power assisted gear position of the power steering assembly. The direction changing wheel of the vehicle is a front wheel or a rear wheel of the vehicle.