Steering Actuator Roadway Condition Detection

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Solution Overview

Problem

Existing methods for determining roadway conditions require additional sensors, making them costly and inefficient, and fail to accurately detect inhomogeneous road surfaces without precise friction coefficient measurements.

Innovation Solution

A method utilizing existing steering actuators in vehicles to detect and compare steering forces on opposite wheels, generating an inhomogeneity signal to determine homogeneous or inhomogeneous road conditions, which is then used to stabilize the vehicle by applying compensation torques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional sensors are used to detect roadway conditions, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improveroadway condition detection accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The steering actuators, originally designed for steering control, are repurposed to also detect roadway conditions by monitoring steering torque and force values. This multi-functional use of existing components eliminates the need for additional dedicated sensors, resolving the contradiction between measurement precision and device complexity

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

Solution Approach 2:

The steering actuators perform self-diagnosis and self-characterization by analyzing their own operational parameters (steering torque, steering force) to determine roadway conditions. This self-service approach allows the system to gather roadway information without external sensing equipment, addressing the contradiction effectively

Inventive Principle:
Principle #25Self-service

2Device complexity

If steering actuators are used to detect roadway conditions, then device complexity is reduced, but measurement precision may worsen

Engineering Contradiction:
Improvedetection system complexityVSAvoidroadway condition detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces traditional mechanical sensing systems with an electronic/electromechanical approach by using the steering actuators' existing sensors and control electronics to detect roadway conditions. This substitution maintains measurement precision while reducing overall system complexity

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

Solution Approach 2:

The system continuously monitors steering torque and steering force values from the actuators, compares them against reference data, and uses this feedback loop to accurately determine roadway conditions. The feedback mechanism ensures high measurement precision is maintained despite using existing actuators rather than dedicated sensors

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3863898B1Method for determining a roadway condition and vehicle having at least two wheel-selective steering actuators
Publication Date: 2022.08.24 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP3863898B1 patent drawingFigure 1~2

AI summary

The present invention relates to a method for determining a roadway condition by means of steering actuators, at least two steering actuators being arranged on respective vehicle wheels (01). The method provides that, in a first step, a measurement variable of the first steering actuator is sensed. In a further method step, a measurement variable of the second steering actuator is sensed. According to a further method step, the sensed measurement variables of the two steering actuators are compared with one another, and in a further method step an inhomogeneity signal is determined from the deviation between the sensed measurement variables of the two steering actuators. If the inhomogeneity signal lies within a tolerance range, a homogeneous roadway condition exists. If the inhomogeneity signal lies outside the tolerance range, an inhomogeneous roadway condition exists. The invention furthermore relates to a vehicle having at least two wheel-selective steering actuators.