Electromechanical Steering Rotor Position Road State Analysis

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electromechanical steering systems and methods for determining roadway conditions are limited in accurately assessing road state, particularly in distinguishing between various road features like transverse joints, cobblestones, bumps, and potholes, and adapting vehicle systems accordingly.

Innovation Solution

An electromechanical steering system incorporating an electric servomotor, motor position sensor, and evaluation and control unit that detects changes in rotor position independently of driver inputs, using frequency analysis of time signals from the motor position sensor, vehicle speed, yaw rate, and manual steering torque to classify road conditions, and optionally considering ambient temperature and rain information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If motor current evaluation is used to determine roadway condition, then the system complexity is reduced, but the measurement precision of roadway state deteriorates

Engineering Contradiction:
Improvesystem complexityVSAvoidroadway state determination accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces mechanical/current-based sensing with a motor position sensor that detects rotor position changes. This substitution enables more precise measurement of roadway conditions by directly measuring positional deviations caused by road disturbances, rather than inferring them from motor current variations.

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

Solution Approach 2:

The motor position sensor acts as an intermediary between the roadway disturbances and the control system. It translates physical road-induced rotor position changes into measurable signals, providing an indirect but accurate method of roadway state detection without requiring direct contact with the road surface.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple parameters (vehicle speed, yaw rate, manual steering torque) are taken into account for roadway state determination, then the measurement precision improves, but the device complexity increases

Engineering Contradiction:
Improveroadway state determination accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The evaluation and control unit is designed to perform multiple functions: it processes motor position sensor data, integrates additional vehicle parameters (speed, yaw rate, steering torque), and adapts both steering and suspension systems. This multi-functional approach consolidates complexity into a single control unit rather than requiring separate systems for each function.

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

Solution Approach 2:

The patent merges the evaluation of multiple independent parameters (motor position changes, vehicle speed, yaw rate, manual steering torque) into a unified roadway state assessment process. By combining these data streams in the evaluation unit, the system achieves comprehensive road condition detection without requiring separate processing systems for each parameter.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the steering system is adapted based on determined roadway state, then the handling and safety improve, but the loss of time for system adjustment occurs

Engineering Contradiction:
Improvehandling and safetyVSAvoidsystem adaptation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system continuously monitors motor position changes and evaluates roadway conditions in real-time, maintaining an updated assessment of road state. This preliminary evaluation ensures that when adaptation is needed, the control unit can immediately implement appropriate adjustments without delay for initial detection or analysis.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements continuous feedback through the motor position sensor that detects rotor position changes caused by roadway disturbances. This feedback loop enables the evaluation unit to rapidly identify road conditions and trigger adaptive responses, minimizing the time between disturbance occurrence and system adaptation.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP2196379B1Electromechanical steering and method for determining the status of a route
Publication Date: 2012.08.01 VOLKSWAGEN AG
  • EP2196379B1 patent drawingFigure 1~2D

AI summary

The element (1) has an electrical servo motor (3) whose rotor position is detected by a motor position sensor (5). Changes of the rotor position of the electrical servo motor caused by steering inputs of a driver are detected by the motor position sensor. A route status e.g. transverse joints, of the electrical servo motor is determined based on changes of the rotor position of the electrical servo motor. Vehicle speed and/or surrounding temperature of the vehicle and/or yaw rate and/or manual steering torque of the driver and/or information about rain quantity are determined. An independent claim is also included for a method for determining a route status of a motor vehicle.